Tape Cartridge Apparatus Including A Silence Responsive Positioning Control

Abstract

A control for fast forward run or rewind operation of tape transports which automatically causes the tape to resume its normal operating speed, responsive to the detection of a silence between recorded passages on the tape during the fast movement of the tape.

Description

BACKGROUND OF THE INVENTION

In using tape transports with provision for fast forward and rewind operation, when the listener desires to skip a portion of the tape being played or to play back a passage of the tape which has already been played, the tape drive is shifted to transport the tape typically at a speed which is 20 to 30 times the normal playing speed. One major problem with such operation of tape transports lies in determining the exact point at which the tape will stop when the high speed drive is deactivated if the listener must use a hit and miss technique with only the diameter of the tape wound on the spool as a guide. In recent years cartridge and cassette type pre-recorded tapes and play back devices which are loaded simply by introducing the cartridge or cassette into a recess provided for the purpose have appeared on the market and have extended the use of tape machines to automobiles and other activities in which more extensive manipulations than the mere loading cannot be allowed to distract attention from a main activity.

Various methods have been suggested for overcoming the uncertainty in stopping the fast movement of the tape. For example, a counter can be used to determine the number of turns of a take-up spool which separate certain passages from a reference point, such as the beginning of the tape. Control devices automatically stop the tape as soon as the take-up spool has completed a predetermined number of rotations. However, this technique requires the laborious and painstaking determination of the number of turns on the take-up spool which separate the different passages on the tape, and also requires a precise positioning of control members producing the automatic deactivation of the fast forward or rewind drive.

The different passages recorded on a commercially recorded tape are conventionally separated from one another by periods of silence the duration of which is about 3 to 7 seconds. In playing this type of a recording, the user may want to skip a selection, or passage, which is about to be played and go on to one which he likes better, or he may desire to repeat a selection which he has already heard and likes. In either case, he would like playback to begin at the start of his desired selection.

DESCRIPTION OF THE INVENTION

It is an object of this invention to provide a control device for stopping the fast forward run or rewind of the tape in tape machines, so that the playing back of the tape can be resumed in a silence interval preceding the recorded passage which is desired to be played back.

Another object of the invention is to provide a control device for stopping the fast forward or rewind of the tape in response to a detected silence irrespective of when this silence occurs on the tape with respect to the start of the tape or the revolutions of the reels. A further object of the invention is to provide a tape transport in which the silence responsive control device is operative only during the fast forward or rewind operation of the tape.

Still another object of the invention is to provide a control device for automatically stopping the fast forward or rewind of the tape responsive to a conventional commercial sound recording.

A still further object of the invention is to provide a control device for stopping the fast forward or rewind of tape in a tape transport responsive to a silence interval between recorded passages on a tape without interferring with any of the other functions of the tape recorder.

Another object of the invention is to provide a device which automatically stops the fast forward run or rewind of the tape in the silence preceding that portion of the recorded passage which is to be played back, while simultaneously bringing the normal playback members and drives into operation.

A still further object of this invention is to provide the above-mentioned silence response feature in a tape transport for playing cassette type cartridges, said transport having the silence controlled elements efficiently and economically integrated with the electromechanical switches and linkages of the tape transport.

Other objects and advantages of the invention will become apparent from the following detailed description and the accompanying drawings.

FIG. 1 is a plan view of a tape transport with the silence responsive control device of the present invention incorporated therein and the circuit of the control device shown in partial block form;

FIGS. 1a and 1b are detail views showing the latching mechanism (illustrated in FIG. 1 in the released position) in the playing and intermediate positions, respectively;

FIG. 2 is a fragmentary partial horizontal section of the tape transport showing the actuating lever;

FIG. 3 is a plan view illustrating the tape transport of FIG. 1 with a cassette partially inserted;

FIG. 4 is a plan view similar to FIG. 1 and showing the cassette and carriage shifted to the playing position for normal sound playback;

FIG. 5 is an overall view of the tape transport similar to FIG. 1 and FIG. 4 except that the cassette and carriage are shown in the intermediate position for fast forward or rewind;

FIG. 5a is a detail view of the locking mechanism which holds the shiftable carriage and the cassette in the intermediate position as shown in FIG. 5;

FIG. 6 is a fragmentary partial horizontal section corresponding to FIG. 5 showing the actuating lever position for fast forward or rewind operation;

FIG. 7 is a plan view similar to FIGS. 1, 4 and 5 showing the tape mechanism during the ejection of the cassette resulting from an inward thrust on the actuating lever;

FIG. 8 is a detail drawing showing the second scanning head in contact with the tape in the cassette and slidably mounted on the frame;

FIGS. 9 and 10 are simplified plan views of an alternative form of lever mechanism and show in partial block form a switching control; and

FIGS. 11 and 12 are diagrams in partial block form showing the circuits of the silence responsive control.

While the invention has been described in connection with certain preferred embodiments, it will be understood that I do not intend to be limited to the particular embodiments shown but intend, on the contrary, to cover the various alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined in the appended claims.

Turning then to the drawings, there is shown in FIG. 1 a tape transport which is adapted to receive a tape cartridge of the cassette type. The principal features and method of operation of the tape transport will be briefly described as they relate to the present invention, and a more detailed description of the mechanism can be obtained by referring to my U.S. Pat. No. 3,385,534.

The tape transport comprises a fixed frame or chassis 1 having a pair of longitudinal guides 2, 3 attached to the opposite lateral sides of the frame 1 and defining a slot into which a cassette 4 (see FIG. 3) can be introduced and by which the cassette 4 is confined to movement in a single plane at all times. The drive elements of the tape transport are supported on a movable plate or carriage 5, hereinafter sometimes called the drive carriage, and include a capstan 6 and reel drive spindles 7, 8. This carriage 5 forms a movable frame which is carried parallel to the plane of cassette movement and which moves together with the cassette and toward the face of the cassette as the cassette after being inserted into the machine moves to the playing position, so as to bring the drive elements on the carriage 5 into engagement with the operative elements of the cassette 4. For this purpose, the drive carriage 5 may be suspended from the chasses 1 by four links (not shown) which are disposed at each corner of the plate to form a parallelogram linkage which is collapsable upon the introduction of the cassette 4 to allow the carriage plane to move toward the cassette plane. This structure is further explained in my U.S. Pat. No. 3,385,534 previously mentioned.

So that the movable frame follows the movement of the cassette as it is introduced into the slot and along the guides, a pair or tubes 11, 12 are provided which move in slots in the fixed frame 1. The tubes 11, 12 are borne by a pair of rods 13, 14 which extend perpendicularly from and are fixed to the drive carriage 5. Thus, as the cassette is introduced into the guides 2, 3, it will first come in contact with the tubes 11, 12, forcing the rods 13, 14, and therefore the movable carriage 5 to which the rods are fixed, to move with the cassette and toward the face of the cassette 4 (due to the collapse of the parallelogram). The movement of the carriage toward the cassette brings the drive elements through the openings in the side of the cassette to engage the operative elements therein.

As the cassette 4 containing a tape 4a reaches playing position (FIGS. 3 and 4) the forward surface of the tape in the cassette comes in contact with a playback sound head 15 and a pinch roller 16, the playback head 15 being fixed directly to the fixed frame 1 and the roller 16 being journalled to a pivot arm 18 which is carried on the fixed frame 1 and tensioned by a spring 19. While a single sound head 15 is shown attached to the frame, it will be understood that a plurality of sound heads including a recording head, reproducing head and an erase head, could be employed in the same manner.

In the playing position, as shown in FIG. 4, the capstan 6 engages the tape against the resiliently held pinch roller 16 to draw the tape past the playback sound head 15. In addition, the take-up and supply reels 7a, 8a, respectively within the cassette 3 are engaged by the take-up reel spindle 7 and the supply reel spindle 8 which are carried by the drive carriage 5.

Means are also provided for latching the drive carriage 5 in the playing position in a manner which permits shifting of the carriage 5 and the cassette 4 to an intermediate position (see FIG. 5) in which the cassette is withdrawn from the pinch roller 16 and the sound head 15 while the drive elements borne by the carriage 5 cause rapid movement of the supply and take-up reel spindles 7, 8 and are effective to transport the tape in the fast forward run or rewind functions. This aspect of the construction is described in detail in my U.S. Pat. No. 3,429,519, and involves a latching lug 25 coupled to the drive carriage 5 and movable in a slot 26 of the fixed frame 1 to a latch position behind a pivotable latch 27 which is secured to the fixed frame 1 and holds the drive carriage 5 in the playing position. In order to afford a limited degree of movement for the drive carriage 5 while still being held by the latch 27, the latching lug 25 is not fixed directly to the drive carriage 5 but rather is secured to the end of a lever 28 the opposite end of which is held by a pivot pin 29 fixed to the carriage. This lever 28, as shown in FIGS. 1a and 1b, is resiliently held by a strong spring 30 against a stop 31. Both the stop 31 and a spring attachment spindle 32 are borne by the movable carriage, thereby restricting the swing of the latching lever 28 solidly in one direction and resilient in the other direction. The pivotable latch 27 pivots around a spindle 35 which is fastened to the frame 1 while being resiliently urged by a spring 36 toward movement in a counterclockwise direction about said spindle 35. The latch 27 is provided with a shoulder 38 behind which the lug 25 is latched in the playing position and also has a second shoulder 39 which is functional during the manual release operation later described.

As the cassette 4 is inserted into the guides 2, 3 and the drive carriage 5 moves to the operating position, the lug 25, moving in the slot 26, momentarily displaces the latch 27 as shown in FIG. 3 due to the cam effect of the lug 25 on the angled portion of the shoulder 38. As the lug 25 rides over the shoulder 38 the force of the spring 36 brings the latch essentially back to its original position, retaining the lug 25 on the shoulder 38 and holding the carriage in the playing position. A pair of carriage return springs (not shown) may be provided to urge the carriage to the released position. When provided, such return springs oppose the latch spring 30 which must be strong enough to overpower such carriage return springs and to hold the pin 25 against the shoulder 38 and the lever 28 firmly against the stop 31 during operation.

Means are also provided of the type described in detail in my U.S. Pat. No. 3,429,519, for manually shifting the drive carriage 5 and the cassette 4 from the playing position to an intermediate position in which the tape is released from contact with the pinch roller 16 and the sound playback head 15 to assume a position for fast forward run or rewind functions, and the fast drive is engaged for forward or rewind operation. This shift is accomplished against the force of the latch spring 30 which tends to urge the carriage 5 to the normal operating position. In the present configuration a control lever 40 is provided for this purpose (FIG. 2) having a manually engageable button 41 on the end extending beyond the frame 1. This lever 40 extends substantially parallel to the guides 2, 3 into the mechanism of the transport and is pivotable about a spindle 43 fixed to the frame 1.

Connected functionally and mechanically to the lever 40 is a cross member 44 having transverse arms 45 and 46 extending perpendicular from the lever 40. Although the lever 40 is capable of an independent longitudinal movement for a short distance into the transport for a purpose hereinafter described, said lever 40 can be presently viewed as forming a rigid cross with the cross member 44 for shifting the carriage to the intermediate position for the fast forward or rewind function. To this end, the lever 40 bears a pin 48 which interacts with a slot 49 of the cross member 44. Also the pin 43 borne by the frame 1 passes through the cross member 44 to engage a slot 50 in the lever 40 (FIG. 2).

In operation, a lateral thrust (FIGS. 5 and 6) in either direction on the button 41 will cause both the lever 40 and the cross member 44 to pivot about the common fulcrum point at pin 43, the result being that the arm of the cross member opposite the direction of lateral thrust will inpinge on the tube 11 or 12 which is coupled to the movable drive carriage 5 via the rod 13 or 14. This in turn causes the entire carriage to shift against the force of the latch spring 30 to the second position for fast forward run or rewind operation.

FIG. 6 shows this shifting operation in detail. As the button 41 is pushed to the right, the transverse arm 45 pivots counterclockwise and exerts a force on the drive carriage 5 via the rod 13 attached thereto. As the button 41 is pushed further, the carriage moves back from the operating position against the force of the spring 30. Note the function of the lever 28 which, although still latched at the lug 25, nevertheless pivots about the spindle 29 to allow movement of the drive carriage 5. As the carriage swings back to the second position, the tape 4a is released from the pinch roller 16 and the playback head 15, but other elements, namely the reel drives 7 and 8, still engage the reels 7a and 8a, respectively. Thus the fast forward run or rewind of the tape can be accomplished by these same drive elements. For a detailed explanation of the other drive elements and mechanical linkage employed for driving the reels once they have assumed the second position for rapid movement (see FIG. 6) see my U.S. Pat. No. 3,429,519 dated Feb. 25, 1969.

One of the problems found by the operator using the fast forward or rewind drive functions of a tape transport such as disclosed in my said prior patent, is in keeping track of the tape as it moves at fast speed in the cassette. The present invention is aimed at this problem and as one of its main features provides for automatically stopping the fast forward or rewind movement of the tape. In the present case, the movement is stopped in the silence interval before the next preceding (in rewind) or next following (in fast forward) recording on the tape. The invention also provides for manual override of the automatic stop feature, but with the feature in operation the present invention allows the operator to advance the tape so that he may hear the next recording, or to rewind the tape so that he may rehear the same recording, easily and fully automatically merely by pressing and then releasing the fast forward-rewind actuating lever.

In carrying out the invention means are provided for automatically locking the drive carriage 5 in the intermediate (fast forward-rewind) position against the resilient force urging said carriage toward the playing position after the button 41 has been pushed to engage the fast forward and rewind drive and the drive carriage 5 has been shifted to its intermediate position. For this purpose locking means are provided comprising a locking lever 60 having an extension arm 61 with a roller wheel 62 at its end (FIG. 5), said roller wheel acting in concert with a holding finger 63 which is also a part of the locking lever 60. The lever 60 pivots about a spindle 64 attached to the fixed frame 1 to assume the several positions shown in FIGS. 1, 4, 5 and 7. In accordance with the automatic nature of this locking means, the lever 60 is resiliently urged toward the position shown in FIG. 1 by a spring 65. Also essential to the control of the locking lever 60 is a control rod 67 connected to the lever 60 by a pin 68 and interposed between the lever 60 and the latch 27 so as to transfer the swinging motion of the latch 27 to rotate the lever 60 so that the lever 60 is swung out of the way by the rod 67 as the carriage 5 moves to the operational position as hereinafter described.

In the present embodiment a tripping arm 70 is rigidly attached to the locking lever 60 and pivots therewith about the spindle 64 to cooperate with a switching plate 71 via a pin 72 attached thereto so as to make and break the various circuit connections for engaging the silence detection circuitry (as later described). The switching plate 71 is normally held in the position shown in FIG. 1 by the force of the spring 73 attached to a fixed post 74 which is supported by the frame 1. The switching plate 71 slides in a switch housing 75 under the force of the spring 73, but movement in the forward direction is restricted by a stopper 76 at the rear end of said plate 71 as viewed in FIG. 1.

Means are also provided for unlocking the carriage 5 from the intermediate or second operating position for movement back to the first operating position for normal playback, said unlocking to be accomplished upon detection of a period of silence on the tape during fast forward run or rewind. As herein shown, said means includes a second sound head 80 for scanning the tape during fast forward run or rewind, a silence detection circuit 85 which receives the signal from the sound head 80 after amplification by an initial amplifier 90, and an unlocking electromagnet 100 which responds to the signal generated by said silence detection circuit 85 upon detection of the silence interval.

As shown in FIG. 1 and more detailedly shown in FIG. 8, this sound head 80 is slidably connected to the frame 1 via a slide member 81 which moves in a channel 82 fixed to the frame 1. In order that the second sound head 80 might maintain a pressure on the tape 4 in both the playing and intermediate positions, a spring 83 is provided which is fixed to the frame 1 at one end and to the slide member 81 at the other.

The electromagnet 100, when energized, acts to pull in a core shaft 101. A pin 102 is unitary with the shaft 101 and impinges on the outer edge of the locking lever 60 to force the lever 60 to the unlocked position when the electromagnet 100 is energized. Referring to FIG. 5, which shows the carriage 5 in the fast forward or rewind position, it is seen that the movement of the core shaft 101 into the electromagnet 100 will rotate the lever 60 about the spindle 64, causing the roller 62 to pass over the tube 12 and thereby release the carriage 5 for movement under the force of the latch spring 30 to the playing position shown in FIG. 4.

It is desirable to have the pick-up circuitry connected to the proper sound head during the various phases of operation described above, and for that purpose, two primary channels are utilized for detecting activity on the tape: a sound playback channel, and a silence-detect channel.

The sound playback channel is comprised of the sound head 15 having an output lead 110, a preamplifier 90 having input and output leads 91 and 92 respectively, and a conventional audio amplifier 120 having an input lead 121 and an output speaker 122. These elements are properly connected together by the action of a pair of contact arms 71a and 71b of the switching plate 71, if and only if the carriage is in the playing position as shown in FIG. 4. Note the heavy lines of the figure showing the signal path for sound playback.

The silence-detect channel utilizes the second sound head 80 having an output lead 81, the same preamp 90 used for normal playback, and a silence detecting circuit 85 having an input leads 86 and a pair of output leads 87, 88 running to the unlocking electromagnet 100. These elements are operational only when the carriage is in the fast forward run or rewind position as shown in FIG. 5, in which the switching plate 71 is in the lower position, closing the signal path as shown by the heavy lines.

Thus, the upper contact arm 71a of the switching plate 71 serves to switch the output line 92 of the preamp 90 between the input line 121 of the audio amplifier 120 and the input line 86 of the silence detection channel 85. Similarly, the second contact arm 71b switches the input line 91 of the preamp 90 between the output lines 110 and 81 of the respective sound heads 15 and 80.

The operational aspects of this transport are summarized briefly as follows:

RELEASE POSITION TO PLAYING POSITION

Before insertion of the cassette into the transport the mechanism is in the state shown in FIG. 1. Note particularly the position of the locking lever 60 and the switching plate 71. As the cassette 4 is inserted in the guides 2, 3, the forward edge of its plastic case (FIG. 8) will impinge on the slide member 81 of the second sound head 80 as the head engages the tape 4a. This sound head 80, under the force of the spring 83, will maintain a pressure on the tape at all times until the cassette is again released from the transport. As the cassette is forced further into the transport, its leading edge will impinge on the tubes 11, 12 to engage the shiftable carriage 5. As the carriage moves forward into the transport, it also moves upward toward the cassette and the drive elements on the drive carriage 5 (capstan 6 and reel drives 7 and 8) engage the operative elements of the cassette through the holes provided. At the same time, the lug 25 of the latching lever 28 moves up the left edge of the latch 27 and exerts a force on the angled back of the shoulder 38, causing the latch 27 to pivot, as shown in FIG. 3. This in turn causes the locking lever 60 to be moved out of the way via the control rod 67, thereby allowing the tube 12 to pass to the left of the roller 62 of the locking lever 60. As the tube 12 moves past the roller 62, it forces the locking lever 60 even more to the right, causing the tripping arm 70 to move the switching plate 71 rearward. As the cassette 4 and the carriage 5 reach the position shown in FIG. 4, the playback sound head 15 and the pinch roller 16 assume their paying position, and the drive elements of the carriage 5 fully engage the elements in the cassette 4. The lug 25 passes over the shoulder 38 as the latch 27 swings back to lock the carriage 5 in place. Thus the cassette 4 reaches the playing position and the capstan 6 drives the tape in the forward direction. Note that the switching plate 71 has finished its travel and closed the contacts to complete the sound playback channel as indicated by the heavy lines in FIG. 4.

PLAYING POSITION TO INTERMEDIATE POSITION

The cassette 4 may be manually moved to an intermediate position for fast forward run or rewind of the tape 4a and automatically released and returned to the playing position after a length of tape has been moved from reel to reel in the forward or rewind direction. If the manually engageable button 41 is thrust to the right as shown in FIGS. 5 and 6, as the fast drive is engaged to drive the tape from left to right in the cassette, the transverse arm 45 of the cross member 44 acts on the rod 13 to move the carriage 5 back to the intermediate position shown in FIG. 5. Although the latching lug 25 remains latched by the shoulder 38, the carriage 5 moves back against the force of the spring 30 acting on the lever 28. Also the tube 12 has been backed off far enough to allow the roller 62 to pass in front of it and, in cooperation with the extended finger 63, lock the carriage in the intermediate position. (See FIG. 5a). Also the return of the locking lever 60 has allowed the switching plate 71 to move forward to complete the signal path for silence detection as shown in FIG. 5 by the heavy lines. The second sound head 80 remains in contact with the tape 4a to scan for silence intervals thereon while the pinch roller 16 and the playback sound head 15 are no longer functional. The arrow in FIG. 5 shows the direction of the tape as it moves rapidly in this fast mode. In this position the reel drives 7 and 8 are still in engagement with the cassette and serve to effect the fast movement of the tape as described in my U.S. Pat. No. 3,429,519

INTERMEDIATE POSITION TO PLAYING POSITION

SILENCE RESPONSE

In accordance with this invention, the fast movement of the tape 4a is terminated responsive to the silence interval between selections on the tape 4a, which interval is of a predetermined minimum duration at high speed corresponding to 3 to 7 seconds of playback speed. In the present case, upon detection of the silence interval by the control circuit, the locking lever 60 is disengaged to release the drive carriage 5 and allow it to return to the playing position.

For the detection of the silence, the second sound head 80 reads the sound track; the signal picked up by the head is conveyed to the silence detecting circuit 85 which is effective when a silence interval appears on the sound track to produce on the output lines 87 and 88 a signal sufficient to energize the electromagnet 100. This induces the core shaft 101 to "pull-in" and, via the attached pin 102, rotate the locking lever 60 about its pivot point at 64. This causes the locking wheel 62 to roll to a position slightly beyond the rectilinear trajectory of the tube 12, the offset from the tube 12 being opposite that shown in FIG. 5a. As the tube 12 moves to the left of the wheel 62 the force of the spring 30 becomes effective to urge the carriage 5 back to the playing position. The locking lever 60 and the switch plate 71 move to the position shown in FIG. 5 as the tape moves back into contact with the pinch roller 16 and the playback sound head 15 for normal playback.

PLAYING POSITION TO RELEASED POSITION

As noted previously, the control lever 40 is not permanently fixed to the cross member 44 nor to the spindle 43. Rather the spindle 43 rests in a groove 50 of the lever 40, which allows said lever to be moved by a thrust longitudinally on the button 41. Since the cross member 44 is prohibited from moving further into the transport by its attachment to the frame at the spindle 43, the lever 40 is also slidably connected to said cross member 44 due to a pin 48 of said control lever 40 which acts in a slot 49 of the cross member 44. As shown in FIG. 7, the lever can be moved for a short distance into the transport to the point where an attached stud 51 impinges on the inclined plane which forms the back of the shoulder 52 of the latch 27. This movement of the stud 51 will cause the latch 27 to shift about the spindle 35, releasing the latching lug 25 from the shoulder 38. This in turn will release the entire carriage from the playing position to be carried, under the force of release springs (not shown), to the released position shown in FIG. 1.

While the embodiment of the invention shown in FIGS. 1-7 has shown the fast rewind operation of the tape, it is understood that the fast forward run of the tape is controlled in a similar fashion. Thus, referring to FIG. 2, the actuating lever 40 when pushed to the left produces fast forward movement of the tape from right to left within the cassette. The pivoting movement of the cross 44 shifts the drive carriage 5 to the intermediate position, and the fast drive elements are engaged, in the manner described hereinbefore. The automatic release of the drive carriage and its return to the playing position is achieved responsive to a silence interval on the tape, in the same manner previously described.

An alternative manually actuable means for controlling the operation of the tape deck is shown in FIGS. 9 and 10, including push buttons and means for latching the push buttons and thereby the associated control linkages in their operating positions. For purposes of illustration of the function of this alternate form of manually actuable means, the silence detection control system detailed in FIGS. 1-7 has been simplified and shown diagrammatically. Thus, only a single sound head 15 and a single capstan-pinch roller combination 6, 16 are utilized for both the playback function and the fast forward run or rewind function.

Instead of the locking lever 60 used in the preferred embodiment, FIG. 9 and FIG. 10 show a locking member 150 directly controlled by a pair of buttons 152 and 153 for the fast forward or rewind function. FIG. 9 shows the locking member 150 held on one end by a spring 156 and on the other end by the electromagnet 100. The output signals from the sound head 15 are carried by a pair of leads 159 and 160 to the preamplifier 90 having an output lead 92. This output lead 92 is switched via the single-pole double-throw switch 71a to either the conventional playback amplifier 120 or the silence detection circuit 85, which may be of the type shown in FIG. 11. As in the preferred embodiment, the output from the silence detection circuit is fed over a pair of lines 87 and 88 to energize the electromagnet 100. The locking member 150 bears members 164 and 165 each comprising an inclined surface 167, 168 respectively and a retaining latch 172, 173 respectively. The manually actuable fast forward button 152 bears a lug 175 which acts on the inclined surface 167 to cam the locking member to the right when the button is pushed in. The rewind button 153 bears a lug 176 which acts in a similar fashion on the inclined surface 168. The lugs 175, 176 also slip behind the latch 172, 173 to hold the respective button in and the locking member to the right as shown in FIG. 10. Although they are not shown as being functionally related, the contact arm 71a can be considered as acting in unison with the locking lever 150, so that it assumes the position shown in FIG. 9 during normal playback while moving to the position shown in FIG. 10 during fast forward run or rewind.

FIG. 9 shows the locking member 150 in the normal playback position with both the fast forward and rewind buttons 152, 153 in their released positions. In this mode, the normal recording channel is being utilized, this channel comprising the sound head 15, the preamplifier 90; the audio playback amplifier 120 and the output speaker 122. The contact arm 71a makes the connection between the output lead 92 of the preamp 90 and the input lead 121 of the audio amplifier 120, while the input lead 86 to the silence detection circuit 85 remains electrically free.

When the fast rewind button 153 is pushed, due to the force of the lug 176 on the inclined surface 173, the locking member 150 moves against the force of the spring 156 toward the electromagnet 100. As the lug 176 reaches the end of the plane 168, the locking member 150 snaps back to lock the lug 176 behind the retaining catch 173. While the locking member 150 moves, the contact arm 71a closes the connection between the output lead 92 of the preamp 90 and the input lead 86 of the silence detection circuit 85. When an interval of silence appears on the tape the silence detection circuit 85 produces an output signal on the lines 87, 88 to energize the electromagnet 100. This causes "pull in" of the core shaft 101. The buttons 152, 153 are urged toward the released position by resilient means (not shown), so that movement of the locking member 150 by the core shaft 101 will free the lug 176 from the retaining catch 173, thereby allowing the button 153 to return to its released position. As soon as the signal from the silence detection circuit 85 subsides, the core shaft 101 will be released from the electromagnet 100, and the entire locking member 150 will be pulled by the spring 156 to the position shown in FIG. 9. Also the contact arm 71a resumes its connection as shown in FIG. 9.

Here also it will be observed that the fast forward button 86 could have been pushed to achieve the same result electrically. Once again it should be noted that a more detailed explanation of the linkage and drive members for the fast forward run or rewind will be found in my U.S. Pat. No. 3,429,519

One of the principal features of the present invention lies in the control of the tape during the fast forward or rewind operation.

As described above, means are provided for locking the tape transport mechanism in the intermediate position during fast forward or rewind. At the same time, the normal playback circuitry is disconnected and the sound signal from the tape is instead fed to a silence detection circuit which effectively scans the tape for intervals of silence exceeding a predetermined minimum duration, discriminating between short pauses between words and the longer pauses between consecutive passages or musical selections on the soundtrack. Upon detection of said silence interval, elements are activated for unlocking the transport from the fast forward or rewind mode to allow the transport to resume normal playback operation. The silence responsive circuitry also includes means subordinating the detection of silence intervals to the preliminary playback of a period of sound on the tape so that the fast forward or rewind may be activated during the interval between selections without causing immediate trip out thereof, but rather to allow the fast movement of the tape through an entire selection. A second embodiment of the control portion of the present invention includes means for delaying the operation of the silence detection function for a period of time after the fast forward or rewind mode is initiated. This will alleviate not only the problem of starting the fast tape transport in a silence but also the problem which would exist if the user had started to listen to a certain selection before deciding that he would rather hear the previous selection over again. Without this feature the deactivation of the fast forward or rewind mode would occur at the beginning of the present rather than the previous selection, clearly an unwanted result.

Since both the normal playback function and the silence detection function require reproduction of the signal from the tape, the present embodiments show a single initial amplifier, the input and output of which are switched between the silence detection circuitry and the normal playback channel at the proper times. Since the fast forward or rewind of the tape will result in the pick up of frequencies above the audio band, the initial amplifier may include means for enlarging its effective bandwidth of amplification during the fast movement of the tape, as shown in the embodiment of FIG. 11.

DETAILED DESCRIPTION OF CONTROL CIRCUIT

Turning now to the control circuit portion of the present invention, there is shown in FIG. 11 a block diagram of the silence detection circuit and the means responsive thereto. This particular embodiment utilizes a third single pole double throw switch which is designed to act in unison with the two switches 71a and 71b of the locking mechanism illustrated in FIGS. 1 through 7. FIG. 11 shows a playback sound head 15 and the silence detecting sound head 80. A preamplifier 90 having an input lead 91 and an output lead 92 is provided which is functional in both the normal playback mode and the silence detection mode. As described previously, the switching plate 71 performs the following connections during normal playback: it connects the output lead 110 of the sound head 15 to the input lead 91 of preamplifier 90; and the output lead 92 of the preamplifier 90 to the input lead 121 of the conventional audio amplifier 120. The switching plate 71 serves also to connect the silence detecting sound head 80 to the silence detection circuit to provide a means for reading the sound track for silence intervals after the drive carriage 5 has been shifted to the intermediate position for the fast forward or rewind functions and the cassette has been shifted away from the main sound head 15 so that the tape is no longer in operative engagement therewith. The switching plate 71 connects the output lead 81 of the second sound head 80 to the input lead 91 of the preamplifier 90; and the output lead 92 of the preamplifier 90 to the input lead 86 of the silence detection circuit.

The preamplifier 90 is a three stage device with interstage switching for disconnecting response curve correctors and changing the effective band width of amplification. The first stage consists of an input capacitor 201 feeding a transistor T1 having a bias resistor 202, a bypass capacitor 203 and a collector load resistor 204. The collector of T1 feeds the second stage consisting of a transistor T2 driving a collector load resistor 205 and having an emitter bias resistor 206 which is bypassed by a capacitor 207. A third stage is driven from the collector of T2 via a coupling capacitor 210. This stage is arranged in emitter follower form and consists of a transistor T3 having a bias resistor 211 and driving an emitter load resistor 212. While the first two stages contribute voltage amplification, the third stage contributes current amplification for driving other elements in the channel. Connected between the collectors of the transistors T1 and T2 is a frequency compensation circuit for varying the bandwidth of the preamplifier 90. During normal playback operation, a single-pole double-throw switch 215 connects the two collectors together via a capacitor 216 and a resistor 217. These elements are chosen such that, when inserted in the feedback path between the transistors T1 and T2, they improve the frequency response curve of the amplifier. Driving the tape at a high speed effectively multiplies the frequencies recorded on the tape, so that the second sound head 80 picks up a signal containing frequencies far above the audio band. Therefore, during the fast forward or rewind operation the switch 215 connects a feedback resistor 218 between the collectors of T1 and T2 to render the preamplifier uniformly sensitive over the entire frequency range. This mode is illustrated in FIG. 11 in which the switch 215 has disconnected the capacitor resistor combination 216, 217 from the feed back path and instead connected the resistor 218. The output from the preamplifier 90 is AC coupled to the contact arm 71a by a coupling capacitor 219.

For the purpose of producing a DC signal indicating the presence of sound on the tape during the fast forward or rewind there is provided a detector 225, in which a diode 231 rectifies the signal and passes the positive half cycles to an integrating capacitor 232.

The size of the capacitor 232 determines the minimum silence interval which will be effective to trigger the circuitry since it serves to smooth out transients at the terminal 233. This results in a DC signal at the terminal 233 which is high in voltage in the case where there is sound on the tape, and low in voltage when there is a period of silence on the tape. A DC amplifier 240 responds to the signal at the terminal 233 of the detector 225 to amplify and effectively invert the detector output. The amplifier 240 consists of a transistor T4 in a common emitter configuration with a collector load resistor 241 and an output terminal 242. As the DC level at terminal 233 rises, the transistor T4 is driven to saturation and the voltage at its output terminal 242 falls to a low level. When a period of silence appears on the tape, and the DC level at terminal 233 falls, the transistor T4 goes to cut off and the voltage at its terminal 242 goes high.

A problem may arise when the fast forward or rewind is brought into operation during a period of silence on the tape. It would be undesirable for the drive carriage 5 to unlock from the fast forward or rewind (intermediate) position during the same interval of silence, since it is intended that the tape should move rapidly to the previous silence interval or to the next silence interval depending upon whether the user has activated the rapid rewind or the fast forward run of the tape. Thus the present invention includes means for subordinating the silence control to the preliminary playback of a portion of the tape carrying audio activity. To this end, a sound to silence indicator 245 is provided. This circuit 245 includes an invertor 246, a flip-flop 247 of the set-reset (RS) variety, and an AND gate 248. Interposed between the set output 249 of the flip-flop 247 and the input 250 of the AND gate 248 is an integrator consisting of a resistor 251 and a capacitor 252. The reset output 254 is coupled to the other input 255 of the AND gate 248. The output of the DC amplifier 240 is fed directly to the reset input 257 while being fed to the set input 258 through the invertor 246. In operation, the presence of sound on the tape causes the detector output at terminal 233 to be high in voltage and the amplifier output at terminal 242 to be low. Because of the invertor 246, the set input 258 to the flip-flop 247 will be high while the reset input 257 is low. Assuming positive logic throughout the circuit, such an input condition will put the flip-flop 247 into the stable state in which the output terminal 249 is at a high voltage and the terminal 254 is at a low voltage. Since the AND gate 248 requires a high voltage at both of its inputs to produce a high voltage output, its output will be at a low voltage during the presence of sound. If a period of silence now appears on the tape (which is of sufficient duration to allow discharge of the integrating capacitor 232) the output of the detector at terminal 233 will fall to a low voltage, and the voltage at the terminal 242 of the DC amplifier 240 will go high as T4 goes to cutoff. This reverses the input conditions to the flip-flop 247, causing the output at the terminal 249 to fall sharply to a low voltage while the output at the terminal 254 exhibits a step increase in voltage. The step change in voltage as the set output 249 will not be seen at the input 250 to the AND gate 248 due to the storage action of the capacitor 252. Until the capacitor 252 becomes substantially discharged both inputs 250, 255 of the AND gate 248 will be high in voltage, causing a high voltage at the output terminal 259. The cumulative effect of the above described circuit will be to produce an output only when a period of silence is detected on the tape subsequent to the playback of a portion of tape carrying sound.

Although the output signal of the AND gate 248 may be sufficient to drive the electromagnet 100 in some cases, more often such an AND gate will be housed in an integrated circuit and will be vulnerable to inductive transients. For this reason, a final common emitter transistor T5 is provided to isolate the electromagnet 100 from the AND gate 248 and to provide current amplification for driving said electromagnet 100. Connecting the final stage T5 with the electromagnet 100 is a line 88, while a second line 87 runs to a DC power source 89. In order that the electromagnet 100 might become fully energized and remain energized long enough to unlock the fast forward and rewind linkages and switches as previously described, it is necessary that the time constant of the resistor capacitor network 251, 252 be long enough to sustain coincidence at the inputs of the AND gate 248 for the required duration. Another time constant which is significant is the inherent time constant in the detector 225. Detectors of this type perform an integration on the AC signal, and consequently provide a smoothing effect at their output. Therefore, the silence interval must be sufficiently long to cause the output of the detector 225 to go to a low voltage. This feature prevents false triggering from spurious periods of inactivity which may be present during a selection on a tape.

In an alternative embodiment of the present invention, shown in FIG. 12, means are provided to delay the operation of the silence detection circuitry so that it operates to stop the fast movement of the tape only after a period of time has elapsed following the initiation of the fast forward or rewind of the tape. With this arrangement, the user may initiate fast transport of the tape in a silence or begin listening to a selection, and if he doesn't like it he can go on and listen instead to the previous selection again or to the following selection.

Referring to FIG. 12, the switching plate 71 of FIGS. 1 through 7 is shown as acted upon directly by the core shaft 101 of the electromagnet 100 in a manner functionally, but not physically, identical to that shown in FIGS. 1 through 7. The contact arms 71a and 71b are controlled directly by the switching plate 71, however an additional single-pole double-throw switch 270 is also interconnected with the switching plate 71 in the circuit illustrated in FIG. 12. The silence detection circuitry in the signal path is identical to that shown for FIG. 11 up through and including output terminal 242 of the DC amplifier 240.

Therefore, in accordance with the present invention the DC inverting amplifier 240 (FIG. 12) feeds a delay circuit 275 having a pair of transistors T8 and T9 connected in a multi vibrator arrangement. The transistor T8 has an input resistor 280 and a pair of bias resistors 281 and 282 running to a positive supply 283 and ground respectively. A collector dropping resistor 285 and a feedback resistor 286 are also provided for T8. The second transistor T9 is normally biased off by a bias resistor 290 connecting its base to the positive supply 283. The collector load for the transistor T9 includes a large capacitor 291 which is in parallel with the electromagnet 100 via the output lines 87 and 88 previously described. The multi vibrator feedback path includes a delay capacitor 292 and a discharge resistor 293 acting in series with the switch 270 and the feedback resistor 286.

Functionally described, it should first be noted that the switching plate 71 and the contact arms connected thereto are shown in FIG. 12 in a position which they occupy during the fast forward or rewind function. For a logical understanding of the operation of the delay circuit 275, let us first assume that the transport is operating in the normal playback mode and that switches 71a, 71b, 170 and 270 are in the opposite states from those shown in FIG. 12. Since the connection between the collector of T8 and base of T9 is interrupted by the opening of switch 170, T9 is maintained in non-conductive state.

As the fast forward or rewind is activated, the switches controlled by the switching plate 71 make the connections shown in FIG. 12. T8 is forced into hard saturation by the current flowing through capacitor 292 and resistors 293 and 286, causing the collector voltage at terminal 300 to go high, effectively to the source voltage at the supply 283. This high voltage holds T9 in the OFF condition. Irrespective of whether the voltage at the output 242 of the inverting amplifier 240 is high or low, T8 will remain in saturation until the capacitor 292 has charged to a sufficient voltage to curtail the input current flowing through the resistor 286, thereby providing the delayed response which this circuit is intended to provide. When the current through the feedback resistor 286 becomes nominal, T8 becomes substantially controlled by the bias resistors 281 and 282 acting in cooperation with the output from the DC inverting amplifier 240. If that output is low, corresponding to the presence of sound on the tape 4a, T8 will remain in saturation due to the strong input current supplied through the resistor 280. However, when silence is detected on the tape, the output 242 of the amplifier 240 goes to a high voltage, and T8 falls out of saturation to resume a marginal state of conduction. As the current through T8 decreases, the voltage across the resistor 285 also decreases, and the base-emitter junction of T9 becomes forward biased so that T9 starts conducting and energizes the electromagnet 100. This unlocks the transport from the fast forward or rewind mode for the resumption of normal playback. At the instant when the electromagnet 100 becomes energized, the core shaft 101 "pulls in" to trip the switching plate 71 and all of its associated contacts for operation in the normal playback mode. When this happens, the capacitor 292 discharges to ground through the discharge resistor 293 and the switch 270, putting the delay circuit 275 in condition for the next shift to the fast forward or rewind mode.

Claims

I claim as my invention:

1. In combination: a tape transport having a playback speed drive and a fast forward or rewind drive, and manually actuated means for disengaging the playback speed drive thereby to discontinue playback operation and for engaging the fast forward or rewind drive to drive the tape at fast speed selectively in either direction; a sound track pick-up head operatively positioned to engage the tape during playback speed movement; and a control for said transport including, a silence detection pick-up head resiliently mounted and operatively positioned to engage the tape during both fast speed and playback speed movement, and operable while the tape is driven at fast speed in either direction for scanning the sound track of said tape, an amplifier connected to receive and amplify signals from said sound track pick-up head while the tape is driven at playback speed, switching means for disconnecting said amplifier from said sound track pick-up head in response to the manual actuation of said fast forward or rewind drive and for connecting said amplifier to receive and amplify audio signals from said silence detection pick-up representing audio recordings on the sound track of said tape, silence detection circuit means for receiving said audio signals from said amplifier during either fast forward or rewind drive and for producing an actuating signal in response to a silence interval of predetermined minimum duration in said audio signals respectively, in either the forward or reverse direction indicating a silence period between recordings on said sound track, and means operated by said actuating signal for disengaging said fast forward or rewind drive and for re-engaging said playback speed drive to discontinue fast speed operation and resume playback operation automatically upon detection of such an interval in either direction.

2. In combination, a tape transport having a forward playback speed drive and fast forward and rewind drives; and means for disengaging the playback speed drive thereby to discontinue playback operation and for engaging the fast forward or rewind drive to drive the tape at fast speed, and a control for said transport comprising: silence detection circuit means operable during fast speed movement in both directions and including a pick-up head for scanning the sound track of said tape in the direction of movement, means responsive to the engagement of either of said fast speed forward or rewind drives for activating said scanning means for operation while the tape is driven at fast speed in either the forward or the rewind direction, means connected to said scanning means for producing an audio signal representing recording on said sound track, means including a first time delay circuit for producing an actuating signal in response to a silence interval of predetermined minimum duration in said audio signal during movement of the tape at fast speed in either the forward or rewind direction indicating a silence period between recordings on said sound track, means operated by said actuating signal for disengaging the fast speed rewind drive and for engaging the forward playback speed drive to reverse the direction of movement of the tape when the tape is moved fast in the rewind direction, and for disengaging the fast speed forward drive and for engaging the forward playback speed drive when the tape is moved fast in the forward direction to resume normal playback operation in the forward direction automatically after silence interval detection regardless of the direction of fast speed movement of the tape, and a second time delay circuit responsive to the engagement of said fast forward or rewind drive for subordinating the operation of said means for disengaging said fast forward or rewind drive and for re-engaging said forward playback speed drive to the lapse of a preliminary time interval while maintaining the engagement of said fast forward or rewind drive prior to the lapse of said preliminary time interval, thereby subordinating the response to the detection of a silence interval to a preliminary lapse of time so as to permit engagement of the fast forward or rewind drive during a silence interval in the recording, to permit engagement of the fast forward drive just prior to a silence interval in the recording, or to permit engagement of the fast rewind drive just after a silence interval in the recording without causing said fast forward or rewind drive to disengage during said same silence interval.

3. A control for a tape transport, said transport having a normally operable forward playback speed drive and selectively engageable fast speed forward and rewind drives, said control comprising, means operable during fast speed movement in both directions for scanning the sound track of said tape in the direction of movement, means responsive to the engagement of either of said fast speed forward or rewind drives for activating said scanning means for operation while the tape is driven at fast speed in either the forward or the rewind direction, means connected to said scanning means for producing an audio signal during movement of the tape at fast speed in either the forward or rewind direction representing recording on said sound track, means for detecting a silence interval of predetermined minimum duration in said audio signal during either fast forward or rewind operation indicating a silence interval between recordings on said track and for producing an actuating signal upon detection of such an interval, and means operated by said actuating signal for disengaging the fast speed rewind drive and for engaging the forward playback speed drive to reverse the direction of movement of the tape when the tape is moved fast in the rewind direction, and for disengaging the fast speed forward drive and for engaging the forward playback speed drive when the tape is moved fast in the forward direction to resume normal playback operation in the forward direction automatically after silence interval detection regardless of the direction of fast speed movement of the tape; said means for detecting a silence interval in said audio signal and thereupon producing an actuating signal including a rectifier for detecting a minimum amount of audio signal and producing a DC signal therefrom, bistable means set to a first condition by said DC signal and reset to a second condition when said audio signal falls below a minimum level and said DC signal disappears, and first and second gates connected respectively to the complimentary outputs of said bistable means and respectively enabled by said first and second conditions of the bistable means, said first gate responsive to said first condition and remaining energized for a short time after said second condition occurs, thereby to make the outputs of the two gates coincident for a period of time sufficiently long to energize the means for disengaging the fast forward or rewind drive.

4. In a cartridge tape transport having tape drive elements mounted on a movable plate for operatively engaging elements in a cartridge and moving therewith from a release position through a second operating position to a first operating position for normal forward movement of the tape and from said first operating position back to said second operating position for fast forward or rewind movement of the tape, the combination comprising, latching elements for holding said movable plate in said operating positions, including resilient means for connecting said latching means to said plate and for urging said plate toward said first operating position while allowing said plate to be moved to said second operating position, means including a fast scanning pick-up head operable during fast forward and rewind operation for detecting an interval of silence of predetermined minimum duration on the sound track of a tape during either fast forward or rewind operation and for producing an actuating signal in response thereto, said fast scanning head being resiliently mounted on said movable plate so as to apply a constant pressure to the tape during movement to and operation in the second operating position, locking means normally urged toward a position in which said locking means are interposed to prevent movement of said plate to said first operating position for holding said plate in said second operating position, means for disabling said locking means during the movement of said plate from the release position to the first operating position, whereby said plate passes through said second operating position during said movement, means for conveying said actuating signal to unlock said locking means upon detection of a silence interval, and means responsive to said actuating signal for unlocking said locking means to free said plate from said second operating position for movement by said resilient means to said first operating position.

5. In a cartridge tape transport having tape drive elements mounted on a movable plate for operatively engaging elements in a cartridge and moving therewith from a release position to a first operating position for playback speed forward movement of the tape and from said first operating position to a second operating position for fast forward or rewind movement of the tape, the combination comprising: means for manually shifting said plate from the first to the second operating position, said means comprising a spindle fixed to the transport frame, a lever which extends substantially parallel to the path of movement of said plate and which is coupled at one end to said spindle so as to allow rotation about said spindle by a lateral force at the other end, and a cross member connected to an forming a T with said lever near said spindle and extending out in both directions from said lever to abut the forward elements of said movable plate when said movable plate is in the first operation position so that by a lateral thrust on the movable end of said lever and the resultant tilting of said cross member about said spindle said plate under the force of one of the cross member arms will be shifted to the second operating position; and latching means for holding said movable plate in said operating positions, including resilient means for connecting said latching means to said plate and for urging said plate toward said first operating position while allowing said plate to be moved to said second operating position, locking means for holding said plate in said second operating positions against said resilient means, and means for unlocking said locking means to free said plate from said second operating position for movement by said resilient means to said first operating position.

6. In combination: a tape transport providing tape movement at either playback speed or fast speed; a sound track channel including a pick-up head operable while the tape is moved at playback speed for sound reproduction; a silence detection channel including a second pick-up head operable while the tape is moved at fast speed in either a forward or rewind direction for scanning the sound track of said tape, detection circuit means for receiving a signal from said second pick-up head representing recording on the sound track of said tape and for producing an actuating signal in response to a silence interval of predetermined minimum duration in said signal during either fast speed forward or rewind movement of the tape; and means operated by said actuating signal for changing the speed of the tape from fast speed to playback speed upon detection of such an interval; an amplifier; switching means for connecting said amplifier in said sound track channel while the tape is moved at playback speed and in said silence detection channel while the tape is moved at fast speed in either direction; and circuit means connected to said amplifier for enlarging its effective band width of amplification while the tape is moved at fast speed in either direction so that it operates on the higher frequency signals produced by said second pick-up head when the tape is moved at fast speed past said head.

7. In combination, a tape transport having a forward playback speed drive and a fast forward or rewind drive, means for disengaging the playback speed drive thereby to discontinue playback operation and for engaging the fast forward or rewind drive to drive the tape at fast speeds, and a control for said transport comprising; silence detection circuit means operable during fast speed movement and including a pick-up head for scanning the sound track of said tape, means responsive to the engagement of said fast speed drive for activating said scanning head for operation, means including a first time delay circuit connected to said scanning head for producing an audio signal representing recording on said sound track, means for producing an actuating signal in response to a silence interval of predetermined minimum duration in said audio signal during movement of the tape at fast speed indicating a silence period between recordings on said sound track, means operated by said actuating signal for disengaging said fast speed drive and for re-engaging said playback speed drive, and a second time delay circuit responsive to the engagement of said fast speed drive for subordinating the operation of said means for disengaging said fast speed drive and for re-engaging said forward playback speed drive to the lapse of a preliminary time interval while maintaining the engagement of said fast speed drive prior to the lapse of said preliminary time interval, thereby subordinating the response to the detection of a silence interval to a preliminary lapse of time so as to permit engagement of the fast speed drive during a silence interval in the recording without causing said fast speed drive to disengage during said same silence interval.

8. In combination, a tape transport having a forward playback speed drive and a fast forward or rewind drive, means for disengaging the playback speed drive to thereby discontinue playback operation and for engaging the fast forward or rewind drive to drive the tape at fast speeds, and a control for said transport comprising: silence detection circuit means operable during fast speed movement and including a pick-up head for scanning the sound track of said tape, means responsive to the engagement of said fast speed drive for activating said scanning head for operation, means connected to said scanning head for producing an audio signal representing recording on said sound track, means for producing an actuating signal in response to a silence interval of predetermined minimum duration in said audio signal during movement of the tape at fast speed indicating a silence period between recordings on said sound track, means operated by said actuating signal for disengaging said fast speed drive and for re-engaging said playback speed drive, and means responsive to the engagement of said fast forward or rewind drive for subordinating the operation of said means for disengaging said fast speed drive and for re-engaging said playback speed drive to the preliminary detection of an audio signal from said pick-up head while maintaining the engagement of said fast speed drive prior to the detection of said preliminary audio signal, thereby subordinating the response to the detection of a silence interval to the preliminary detection of sound recordings on the sound track of the tape so as to permit engagement of the fast speed drive during a silence interval in the recording without causing said fast speed drive to disengage during the same silence interval.

9. In combination, a tape transport having a forward playback speed drive and fast forward and rewind drives; and means for disengaging the playback speed drive thereby to discontinue playback operation and for engaging the fast forward or rewind drive to drive the tape at fast speed, and a control for said transport comprising: silence detection circuit means operable during fast speed movement in both directions and including a pick-up head for scanning the sound track of said tape in the direction of movement, means responsive to the engagement of either of said fast speed forward or rewind drives for activating said scanning means for operation while the tape is driven at fast speed in either the forward or the rewind direction, means connected to said scanning means for producing an audio signal representing recording on said sound track, means for producing an actuating signal in response to a silence interval of predetermined minimum duration in said audio signal during movement of the tape at fast speed in either the forward or rewind direction indicating a silence period between recordings on said sound track, means operated by said actuating signal for disengaging the fast speed rewind drive and for engaging the forward playback speed drive to reverse the direction of movement of the tape when the tape is moved fast in the rewind direction, and for disengaging the fast speed forward drive and for engaging the forward playback speed drive when the tape is moved fast in the forward direction to resume normal playback operation in the forward direction automatically after silence interval detection regardless of the direction of fast speed movement of the tape, and means responsive to the engagement of said fast forward or rewind drive for subordinating the operation of said means for disengaging said fast forward or rewind drive and for re-engaging said forward playback speed drive to the preliminary detection of an audio signal from said pick-up head while maintaining the engagement of said fast forward or rewind drive prior to the detection of said preliminary audio signal, thereby subordinating the response to the detection of a silence interval to the preliminary detection of sound recordings on the sound track of the tape so as to permit engagement of the fast forward or rewind drive during a silence interval in the recording without causing said fast forward or rewind drive to disengage during the same silence interval.

10. A control according to claim 9 wherein the means for detecting an interval in said audio signal and for thereupon producing an actuating signal comprises means for producing a DC signal in response to a minimum audio signal level and means including a bistable element, having a long time constant associated with one of its outputs, serving as a sequencing device for producing a signal upon a change from sound to no sound recorded on the sound track of the tape only when the silence interval has been preceeded by a preliminary interval of sound.

11. In a cartridge tape transport having a fixed frame and tape drive elements mounted on a movable plate for operatively engaging elements in a cartridge and moving therewith from a release position to a first operating position for playback speed forward movement of the tape and from said first operation position to a second operating position for fast forward or rewind movement of the tape, the combination comprising latching means for holding said movable plate in said operating positions including resilient means for connecting said latching means to said plate and for urging said plate toward said first operating position while allowing said plate to be moved to said second operating position, locking means for holding said plate in said second operating position against said resilient means, said locking means including a lever rotatable about a spindle fixed on said frame and movable to a locked position situated longitudinally between said spindle and an element fixed to said movable plate so as to prevent said plate from being pulled back to the first operating position by said resilient means, and means for unlocking said locking means to free said plate from said second operating position for movement by said resilient means to said first operating position.

12. A cartridge tape transport according to claim 11 in which one end of said lever bears a roller and an extended finger which combine to wedge said element between them when said lever is in the locked position, and in which said lever further extends beyond said spindle away from said end to an unlocking end which is coupled to said unlocking means such that the actuation of said unlocking means causes said lever to pivot about said spindle and, by overcoming the slight amount of resistance of said roller movement over said element, releases said plate to the force of said resilient means, so as to allow its return to said first operation position.

13. A cartridge tape transport according to claim 11 in which said lever further impinges, by a projection thereon, on elements of said latching means, and in which said lever is resiliently connected to said transport frame and is formed with a slot in which said spindle will remain during movement of said lever toward said latching means, whereby a longitudinal thrust on said lever will cause said latching means to disengage and thereby free said plate from the operating positions.