Electrically Operated Door Bolt

Abstract

A solenoid-controlled door bolt locking mechanism designed for use in conjunction with a rotary permutation arrangement, in which a proper setting of a series of rotary multiconductor wafers comprising the permutation arrangement completes an electrical circuit which enables operation of the locking mechanism. The proper permutation setting simultaneously causes a solenoid to retract a holding plunger, which rendered the door locking bolt immobile in the locked position, and the rotary control knob of the permutation arrangement to become mechanically coupled to the door locking bolt. A further rotation of the control knob, subsequent to a proper permutation setting, withdraws the locking bolt and, in reverse direction, locks it again.

Description

BACKGROUND OF THE INVENTION

The invention relates to an electromechanically controlled lock mechanism.

Lock mechanisms are known in which, in the locked position, a door knob or the like, normally used for opening the door, may be rotated without effect until a key is inserted to unlock the mechanism and couple it to the door knob. The mechanism of the present invention behaves similarly except that it is designed for use in combination with a permutation mechanism, correct actuation of which, in accordance with a given sequence of setting operations by alternate rotation of a control knob first in one direction and then in the other to prescribed settings, is utilized to complete an electric circuit path enabling the lock mechanism to be operated.

SUMMARY OF THE INVENTION

In accordance with the present invention there is provided an electromechanically controlled lock mechanism including a bolt, a locking plunger arranged when the bolt is shot to engage in the bolt and hold it in position, a bolt-driving member, a link pin mounted on the bolt for coupling the bolt-driving member to the bolt, a mechanical linkage coupling the locking plunger to the link pin in such manner that as either of the two members is shifted to its active position the other is withdrawn, the arrangement being spring-loaded to urge the plunger into engagement with the bolt, and a magnetic solenoid arranged when energized to withdraw the plunger from the bolt.

Although the lock mechanism of the present invention may be arranged for remote control operation, the bolt driving member being actuated electromechanically, it has been specifically designed to enable the bolt driving member to be mechanically coupled to the control knob of a permutation mechanism so that when the correct combination has been set up, further rotation of the control knob withdraws the bolt and, in reverse action, locks it again. In any permutation lock system for ensuring security of an enclosure against unauthorized access, the system should be such that the combination required to open the door should not be able to be detected by means of touch or stethoscopically assisted hearing, for which purpose electric circuitry is well adapted, while for an electrically controlled system, it should not be possible to ascertain the combination by use of magnetic sensing devices outside the door. No current should therefore flow in the control circuit until the correct combination is set up. It is best that there should be no external leads, which means that the mechanism should contain its own power supplies. This has the disadvantage of risk of battery failure or at least short life of the contained battery. The advantages, however, offered by the self-contained system often outweigh the inherent disadvantages and in the embodiment of the present invention described herein the current drain on the battery is reduced to a minimum, no battery power being required for withdrawing the actual bolt. Other embodiments of the lock mechanism of the invention may incorporate, for remote control purposes utilizing external power supplies, modifications of that described herein, some of these modifications are described in our copending application Ser. No. 84,391 which is primarily concerned with a permutation mechanism mentioned above.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the invention will be described with reference to the accompanying drawings in which:

FIG. 1 is a diagrammatic view of a portion of a door incorporating a lock mechanism according to the invention in association with a permutation mechanism;

FIG. 2 is a diagrammatic illustration of the lock mechanism of the invention;

FIG. 3 illustrates the electrical arrangement of the associated permutation mechanism and the mechanical linkage between control knob and bolt driving member;

FIG. 4 shows one possible combination of control knob settings;

FIGS. 5A-5G illustrate diagrammatically sequence of positions of the lock mechanism of FIG. 2 during unlocking and locking operations; and

FIGS. 6A-6E combined form a timing diagram for the operation of the lock mechanism when combined with the permutation arrangement of FIG. 3.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In FIG. 1 a part of a door 1 is shown closed against its door jamb 2 with a bolt 3 engaged in a socket 4 of the door jamb. A metal box 5 is shown projecting behind the door and contains the lock mechanism for controlling the bolt 3 and a permutation mechanism, actuated by a control knob 6 on the front of the door, by means of which, after performance of a given series of rotations of the control knob in alternate directions to predetermined settings, the control knob becomes mechanically coupled to the bolt and by further rotation may withdraw it and allow the door to be pushed open.

FIG. 2 shows in diagrammatic form the principle of the lock mechanism of the present invention. The bolt 3 is a dead bolt slidable in bearings 7 and 8 fixed in the door, its movement in and out of the socket 4 being limited by means of stops 9 and 10. In some other embodiments within the scope of the invention claimed herein the bolt may be sprung. When the door is locked the bolt is held in its locked position by means of a plunger 11 which enters an aperture 12 in the bolt. The plunger carries a flange 13 which is pressed downwards by means of a lever 14 mounted on a fixed pivot 15, the other arm 16 of the lever riding on the upper surface of a platform 17 surmounting a link pin 18 carried in the bolt. The link pin is urged upwards as viewed in the drawing by means of a compression spring 19. The plunger 11 is mounted in a fixed bearing 20 and may be withdrawn from the bolt by energization of a magnetic solenoid 21. A bolt-driving member 22 is free to slide in bearing 8 along the under surface of bolt 3 and is coupled to the bolt by means of an aperture 23 in the driving member in alignment with link pin 18 when the latter is depressed. This can only happen when the plunger 11 is raised out of its aperture 12. When it is so raised and the bolt is withdrawn by the driving member 22, plunger 11 may be allowed to ride on the surface of the bolt while the lever arm 16 rides on the platform 17 to keep the link pin 18 depressed. The simple lever arrangement illustrated is but one of the possible linkages which may be employed to ensure that when either of the two members, the link pin and the plunger, is in active position, the other member is withdrawn. Similarly the spring-loading of the arrangement may be assisted by or replaced by direct spring-loading of the plungers. In the latter case, with omission of the spring 19 under the platform 17, the lever arm 16 could be provided with a side pin to ride in a longitudinal slot in the platform 17 and the flange 13 on the plunger replaced by a double flanged collar to receive the other end of the lever.

Current for operating solenoid 21 is provided by a battery 24 one terminal of which is earthed and the other terminal of which is connected to the solenoid through a permutation mechanism 25 and a further switch 26, which is represented as being operated by a cam 27. The permutation mechanism 25 contains an arrangement of multi-contact switches, each of which may be set to different angular positions by sequential rotation in alternate directions of the control knob 6, and hence may be referred to as dialing switches, there being only one particular combination of switch settings which provides a through current path. The cam 27 and the control knob 6 are mounted on a common shaft 30. A suitable permutation mechanism 25 is disclosed in our copending application Ser. No. 84,391. The bolt-driving member 22 is actuated, through any convenient rotary-to-reciprocal motion device permitting unlimited rotation of the rotary part, by rotation of the control knob 6 of the permutation mechanism. Cam operation of switch 26 may be replaced by other equivalent arrangements, for example a rotary switch member carrying a wiper, and, although shown separately therefrom, will in practice form part of the permutation mechanism 25.

Insofar as is relevant to the present purpose a suitable arrangement of the permutation mechanism 25 will now be described with reference to FIG. 3 of the accompanying drawings.

The control knob 6 is mounted on a shaft 30 which passes through, without engaging them, a set of three rotors marked Rotor 1, Rotor 2 and Rotor 3. The shaft 30 carries an eccentrically mounted circular disc 31 which rides in a surrounding cam follower member 32 attached to the bolt driving member 22 so that the bolt driving member is reciprocated by rotation of the control knob and remains permanently linked thereto. As stated above, any other convenient type of rotary to reciprocal motion converting device permitting continuous rotation of the shaft 30 may be employed. The rotors are mounted in fixed switch plates 33 and carry wiper arms 34 each of which provides bridging contact between a conductor track 35 and any one of a respective set of contacts 36. The rotors carry a driving peg 37 on one side and a tab 38 on the other side for engagement with the driving peg of the next adjacent rotor. A similar tab 38' is carried by the shaft 30 for engagement with the driving peg on either Rotor 1 or Rotor 3. When the control knob 6 is turned in either direction through a complete revolution it will, in the course of its rotation, pick up an end one of the assembly of three rotors by means of the tab 38' and rotor driving peg. Continued rotation will entrain, by means of their tabs and driving pegs, the other two rotors. When now the control knob is rotated in the opposite direction, it will move through nearly a complete revolution, leaving the three rotors stationary until it again picks up, and entrains, but in the opposite direction, the end rotor which it first engaged. A further near complete revolution will then entrain the second rotor and it may thus be moved to any position short of which its tab engages the third rotor. The direction of rotation of the control knob may now be reversed again and the last of the three rotors set to a position intermediate those to which the other two have been left. Finally the control knob is reversed in direction of rotation again through a specified position intermediate the settings for the last two rotors in which a fourth rotor, keyed to the spindle 30, makes contact with its bridging arm between its associated wiper track 35 and an elongated contact 36'. This arrangement provides the equivalent of the cam 27 and switch 26 in FIG. 2. Only one of each of the set of contacts on the switch plates 33 is connected to carry current through the permutation mechanism. Thus in FIG. 3 the battery 24 is shown connected to the wiper track 35 of Rotor 1, a connection from one of the contacts on its switch plate is made through lead 40 to one of the contacts on the switch plate associated with Rotor 2, the wiper track of Rotor 2 is joined by lead 41 to the wiper track of Rotor 3, and one of the contacts on the switch plate of Rotor 3 is connected to the wiper track of switch 26. The elongated contact 36' on the switch plate of switch 26 is connected to solenoid 21. Thus only when each dialing switch has been set to one particular position and finally the switch 26 set correctly can current flow to solenoid 21. Although direct connections 40, 41 and 42 are shown in FIG. 3 between the three dialing switches and switch 26, a set of three auxiliary setting switches may be used, having a similar arrangement of contacts as on the dialing switches, and the appropriate interconnections made through the setting switches, which thus provide means for changing the combination required to unlock the door. Three dialing switches are shown for convenience, but as many as desired may be used, while the switch plates may typically carry 26 contacts, one for each letter of the alphabet. Thus if, say, 2 of these contacts on Rotor 1 and Rotor 2 cannot be used (so as not to interfere with the settings of Rotor 3 and Rotor 2, respectively) while a further 4 on Rotor 1 are within a prohibited range -- to be explained later -- there are still 26 .times. 24 .times. 20 (= 12,480) permutations provided, while addition of a fourth rotor would provide 24 times as many.

The operation of the arrangement of FIGS. 2 and 3 in unlocking and relocking the door 1 will now be described. Let it be assumed that the bolt-driving member 3 is at its extreme left hand position (as viewed in FIG. 2) when the control knob is set to 180.degree. and that a through current path is set up when Rotor 1 is at 270.degree., Rotor 2 at 45.degree. and Rotor 3 at 300.degree., as indicated in FIG. 4. Let it also be assumed that the pegs 37 and 38 are arranged so that tab 38' on shaft 30 engages with the driving peg on Rotor 1 (rather than Rotor 3). The procedure for unlocking the door is now as follows:

1. Turn control knob clockwise through at least three revolutions and continue to 300.degree..

2. Turn knob anticlockwise through two revolutions (counting from the 300.degree. setting) and continue to 45.degree..

3. Turn knob clockwise through one complete revolution, (counting from the 45.degree. setting) and continue to 270.degree..

4. Turn knob anticlockwise past 180.degree. until it can be turned no further. The bolt is now withdrawn.

For relocking:

5. Turn control knob clockwise past 180.degree. (when the door will be relocked) to 270.degree. and continue for another two complete revolutions to ensure all three rotors have been displaced.

In the unlocking procedure, step one ensures that all three rotors are being carried round with the control knob. In step two, Rotor 3 has been left at 300.degree., the first complete revolution will pick up Rotor 1 by tab 38' engaging its peg on the opposite side to that engaged during step one, and a further revolution is required to pick up Rotor 2. Similarly in step three the complete revolution is required to pick up Rotor 1, Rotor 2 being left at 45.degree.. During step four Rotor 1 is left at 270.degree. so that the correct combination of settings for the dialing switches has been established and the unique current path through them is made. The further sequence of operations during step four will be described in fuller detail with reference to FIGS. 5A-5G and 6A-6E.

The relative positions of the bolt-driving member 22, the bolt 3, the plunger 11 and the link pin 18 are shown diagrammatically at sequential stages (FIGS. 5A to 5D) of the unlocking process and at sequential stages (FIGS. 5E to 5G) of the relocking process. Displacements of the bolt-driving member, the bolt and the plunger are plotted at FIGS. 6A, 6C and 6D respectively, as functions of control knob positions, marked Dial Rotation, while the switch 26 (Cam Switch) and the dialing switch of Rotor 1 are indicated at FIGS. 6B and 6E respectively. In these drawings, as also in FIG. 2, the dimensions of parts, and ranges of movement have been chosen purely for ease of illustration; in particular clearances and tolerance margins have been exaggerated where this is helpful to understanding the operation of the mechanism.

During the initial phase of stage four of the unlocking procedure specified above, as the control knob is moved anticlockwise from its 270.degree. position the current path through Rotor 1 remains established and the bolt-driving member moves to the right as viewed in FIG. 5A. In FIG. 5A the driving member has reached a position with its aperture 23 beneath the link pin 18 but short of the position where the driving member would engage the link pin if dropped. The cam switch is about to close, the corresponding dial setting being represented in FIG. 6A as approximately 105.degree.. The solenoid raises plunger 11 clear of the bolt and the link pin enters aperture 23. In FIG. 5B the bolt-driving member is just in contact with the link pin and is about to start withdrawing the bolt (dial rotation 90.degree., FIG. 6A). At FIG. 5C the bolt has been withdrawn to the extent that the plunger is sufficiently far over the edge of the aperture 12 for it to be held up, if the solenoid is switched off, by the surface 28 of the bolt. After a little further travel, indicated at dial rotation 60.degree. in FIG. 6A, the cam switch is deactivated and the plunger descends on to bolt surface 28, the link pin 18 being thereby maintained in the aperture 23 of the bolt-driving member. The motion continues until the bolt comes against a stop 9, as shown in FIG. 5D. The bolt is now fully withdrawn and the cam switch is open so that there is no drain on the battery. The control knob can be turned no further in the anticlockwise direction from the position then reached, shown in FIG. 6A as just less than 30.degree..

To relock the door the control knob is turned clockwise and the motions described for unlocking are reversed. However, the cam switch operates again during the return motion and, if there were a simple reversal with all parts in the same relative positions as during unlocking, the bolt would be fully shot while still coupled to the driving member by the link pin. This would prevent further rotation of the control knob, so that the solenoid current could not be broken with the door locked. This difficulty is overcome by providing sufficient lost motion in the overall coupling between the control knob (and therefore the switch 26 operating member) and the bolt so that the switch is off by the time the bolt is fully home.

Referring now to FIGS. 5E and 6A-6E, during the first part of the locking motion, the bolt does not move because of lost motion in the mechanism. This lost motion is shown for purposes of illustration to be provided by a considerable elongation of the aperture 23 in the bolt-driving member, though in practice there would be some backlash in the drive between the control knob shaft and the bolt-driving member and the whole of the lost motion required can conveniently be distributed over different parts. Comparing FIGS. 5D and 5E, it will be seen that at the end of the unlocking procedure the left hand end wall of the aperture 23 presses against the link pin 18, but to reverse the motion of the bolt 3 the link pin must be engaged by the opposite end wall of the aperture. Thus in the embodiment illustrated the control knob must be rotated from just under the 30.degree. position to 90.degree. before the bolt starts to move. The cam switch closes at 60.degree., so the solenoid is energized and the plunger 11 fully raised when the bolt starts to move. As the clockwise rotation of the control knob continues, the cam switch falls off at 105.degree. and the plunger is supported again on the bolt surface 28, as shown in FIG. 5F, until it is over the edge of the aperture 12. The end of the plunger is preferably rounded so that as the bolt moves still further to the left of the plunger, urged by its spring-loading slips into the aperture 12, at the same time exerting pressure to drive the bolt home, while the link pin 18 is withdrawn from aperture 23. This is illustrated at X in FIG. 6D.

The door is now locked and the bolt-driving member is free to move further to the left, as shown in FIG. 5G. Clockwise rotation of the control knob should be continued until at 270.degree. it picks up Rotor 1 and then, during two further revolutions, Rotor 2 and finally Rotor 3, so upsetting the dialing switches and preventing the door being unlocked again without repeating the complete unlocking procedure given above. Were the control knob to be left between 150.degree. and 270.degree. immediately after the bolt had been shot, the door could be unlocked again merely by turning the control knob anticlockwise as in step four of the unlocking procedure.

It will be observed that there is some restriction in the setting of Rotor 1 which entails a small reduction in the possible number of permutations provided by the dialing switches. Whereas choice of the setting position for Rotor 3 is arbitrary and that of Rotor 2 is limited only by the few degrees of clearance needed between its tab and the driving peg of Rotor 3, the setting position for Rotor 1 should not lie within the range over which the cam switch is closed, that is in the range of 60.degree. to 105.degree. in the arrangement of FIGS. 5A-5G and 6A-6E. However, if the setting for Rotor 1 were chosen within the range in between the angle, during unlocking, at which the cam switch reopens and that at which the bolt is fully withdrawn (that is within the range 30.degree. to 60.degree. for the embodiment of FIGS. 5A-5G and 6A-6E), then during the last phase of the unlocking procedure at least Rotor 1 would be upset; during locking, in spite of the cam switch closing, the solenoid would not operate and the lost motion provided for in FIGS. 5A-5G and 6A-6E would not be needed. This would also provide a safeguard against the door being locked but, through inadvertence, the full locking process to upset the dialing switches being omitted. Compensation for the loss of the number of permutations available through restriction of the range of settings for Rotor 1 may readily be made by providing a fourth rotor.

While the principles of the invention have been described above in connection with specific apparatus, it is to be understood that this description is made only by way of example and not as a limitation to the scope of the invention as set forth in the accompanying claims.

Claims

We claim:

1. An electromechanically controlled lock mechanism including a bolt, a locking plunger arranged when the bolt is shot to engage in the bolt and hold it in position, a bolt-driving member, a link pin mounted on the bolt for coupling the bolt-driving member to the bolt, a mechanical linkage coupling the locking plunger to the link pin in such manner that as either of the two members is shifted to active position the other is withdrawn, the arrangement being spring-loaded to urge the plunger into engagement with the bolt, and a magnetic solenoid arranged when energized to withdraw the plunger from the bolt.

2. The lock mechanism as claimed in claim 1 arranged such that as the bolt is withdrawn and current to the solenoid is switched off, the plunger rides on a surface of the bolt and, through the mechanical linkage, maintains the link pin in engagement with the bolt-driving member.

3. The lock mechanism as claimed in claim 2 wherein the link pin is spring-loaded and carries a platform, and wherein the mechanical linkage includes a lever one arm of which rides on the platform and the other of which due to the spring-loading, urges the locking plunger to engage in the bolt.

4. The lock mechanism as claimed in claim 2 wherein the bolt is a dead bolt, and the bolt-driving member is coupled through a switch-operating member to a switch having contacts which have to be made to enable current to flow to the solenoid, the coupling being such that the switch contacts are made when the bolt-driving member is moved into position for withdrawing the bolt and are broken again, during withdrawl movement, before the bolt is fully withdrawn.

5. The lock mechanism as claimed in claim 4 wherein the contacts are made and broken again during movement in the opposite locking direction, and wherein lost motion is provided in the overall mechanical coupling between the switch operating member and the bolt sufficient to ensure that during locking movement the switch contacts are broken by the time the bolt is fully shot.

6. The lock mechanism as claimed in claim 4 wherein the bolt-driving member is coupled for reciprocatory motion to a shaft rotatable in either direction and wherein the switch-operating member is mounted upon the shaft.

7. The lock mechanism as claimed in claim 1 further including a permutation mechanism which includes a plurality of dialing switches movable by a control knob and electrically interconnected in such manner that the control knob must be rotated alternately in opposite directions to a sequence of prescribed angular positions in order to set the switches to provide a current path through the permutation mechanism, current to the solenoid being fed along this path, and wherein the control knob is mechanically coupled to the bolt-driving member to actuate it by rotation of the control knob.

8. A combination as claimed in claim 7 wherein the control knob and said plurality of dialing switches are mounted upon a common shaft.