Timer For Controlling The Operation Of Devices And Implements, Especially Stoves

Abstract

A timing mechanism especially for cooking appliances, in which a pointer is adjustable over a clock face to indicate the end of a cooking period, while a dial is adjustable to indicate the duration of the cooking period. A planetary gear arrangement interconnects the dial and the pointer and adjusts one of a pair of clutch elements, the other of which is driven by the timer motor. Adjustment of the dial presets a power control device and when the clutch parts are in a certain relative position they clutch together and initiate the supply of power to the appliance, and which is automatically terminated when the preselected time expires.

Description

The present invention relates to a timer for controlling the operation of devices and implements, especially stoves. In particular the operation concerns a device for kitchen stoves with means for setting the end of a cooking period, the duration of a cooking period, a particularly short cooking period, and the start of the cooking period while indicating means are provided for the three last-mentioned setting means. The device is furthermore provided with a planetary gear transmission for calculating and setting the time for the start of the cooking period from the present termination of the cooking period and the duration of the cooking period. The device also comprises a drive for the timer which simultaneously furnishes the energy for the mechanical control operations and furthermore comprises electric control means for controlling the functions of the device.

A timer of this type for use in kitchen stoves is known. Such known timers comprise a total of three actuating shafts for setting the time of day for the timer, for setting the cooking duration, and for setting a particularly short cooking period while the actuating shaft for the timer is additionally equipped with a hollow shaft for setting the end of the cooking period. For visually indicating the set time concerning the end of the cooking period, the duration of the cooking period and the particularly short cooking period there are provided a total of three indicating devices. The most important feature of such a timer is its planetary gear transmission by means of which after having set the end of the cooking period and the cooking duration, the start of the cooking period is automatically set in the timer so that the person operating the stove does under no circumstances have to make time consuming calculations in this respect. The timer, however, requires a considerable space in view of the fact that three actuating shafts are arranged adjacent to each other including the pertaining indicating devices.

It is, therefore, an object of the present invention to improve a timer of the above-mentioned type so that a timer will be realized which has a considerably decreased height and width while the functions and indicating possibilities of the heretofore known timers will be retained to their full extent.

This object and other objects and advantages of the invention will appear more clearly from the following specification in connection with the accompanying drawings, in which:

FIG. 1 is a front view of a timer according to the invention.

FIG. 2 is a diagrammatic illustration for purposes of explaining the function of the timer according to the invention.

FIG. 3 is a lateral section through the timer according to the invention while the transmission for setting the time for a particularly short cooking period has been omitted.

FIG. 4 is a lateral section similar to that of FIG. 3 while only the transmission for the setting of a particularly short cooking period is illustrated.

FIG. 5 is a top view of the transmission of FIG. 4.

FIG. 6 is a perspective view of the structures shown in FIGS. 1-5.

The present invention is characterized primarily in that a timer is mounted on the front plate of the stove while a first actuating shaft for setting the end of the cooking period is provided which carries a hollow shaft for setting a particularly short cooking period. The invention is furthermore characterized in that a second actuating shaft for setting the beginning of the cooking period is provided and carries a hollow shaft for setting the cooking period. The invention is furthermore characterized in that the first actuating shaft with the indicating device for the cooking period and the hollow shaft mounted on said first actuating shaft and provided with an indicating device for the particularly short cooking period and the hollow shaft on the second actuating shaft are mechanically connected or coupled to the indicating device for the cooking time.

Thus, according to the present invention, the number of the actuating shafts is reduced. This in turn permits a considerable decrease in the overall size of heretofore known timers inasmuch as in view of the new arrangement of the actuating shafts simultaneously also the gear transmission arranged behind the front plate can be compacted to a considerable extent.

A further decrease in the overall size of the timer has been made possible according to the invention by the fact that the indicating device for the end of the cooking period consists of an indicator which by means of a hollow shaft is arranged on the shaft of the timer. Consequently, no indicating device for the end of the cooking period is necessary which would require a space of its own. The indicating devices for the cooking period and for the particularly short cooking period respectively consist of an indicating disc with corresponding numbers which are partly visible behind a window of the front plate. These indicating devices are similar to the indicator for the end of the cooking period coupled through gears with the actuating shafts and the hollow shafts arranged thereon.

According to a further development of the device according to the invention, the indicating discs for the cooking period are also coupled to the drive for the timer in such a way that the discs rotate with the expiration of the set time in a direction counter to the setting direction so that always the time still left is indicated.

According to a still further development of the present invention, the first actuating shaft (end of the cooking period) is through driving means operatively connected to the sun wheel of the planetary gear transmission while the hollow shaft on the second actuating shaft (cooking time) is coupled to the outer wheel of said planetary gear transmission. Furthermore, the planetary gear wheel is operatively connected to coupling means which at the start of the cooking period actuate an electric switch for the supply of current, and connect the planetary gear transmission to the drive for the timer. The outer wheel of the planetary gear transmission cooperates with a control lever which at the end of the cooking period--a certain position of the outer wheel being associated with the control lever--actuates an electric breaker for the current supply and furthermore through the intervention of the coupling means separates the planetary gear transmission from the drive for the timer.

The coupling means according to a further development of the invention comprises an axially displaceable coupling disc provided with a bore or groove and also comprises a clutch jaw connected to the planetary gear which jaw cooperates with the bore or groove of the coupling disc in a positive manner when the clutch is engaged.

Furthermore, according to the invention, there may be provided a brake between the sun wheel of the planetary gear transmission and the first actuating shaft which brake has such a braking moment that on one hand the driving energy of the drive for the timer will not be sufficient to turn the sun wheel while on the other hand a setting of the end of the cooking period through the first actuating shaft will be possible without difficulties.

Referring now to the drawings in detail, FIG. 1 illustrates the dial face of the timer 1 mounted on a front plate F. The timer furthermore comprises a pointer 2 for indicating the hours and a pointer 3 for indicating the minutes while the seconds are indicated by the pointer 4. For purposes of setting the end of the cooking period, there is provided a setting indicator 5. The actuation of the functions of the timer is effected by a total of four control knobs arranged on two double shafts. By means of the knob 6 the end of the cooking period is set while at the same time the adjusting indicator 5 is moved. By means of a knob 7 a timer for a particularly short cooking period is set which at the expiration of said short time sounds off. The setting of the pointers 2 and 3 is effected by a knob 8. A fourth knob 9 serves for setting the intended cooking duration. For purposes of indicating the particularly short cooking period and the longer cooking periods, there are respectively provided two indicating devices 10 and 11 with dials visible through a window 10' and 11; of the front plate F. The arrangement of the indicating dials is such that the respective still remaining time of the set time is indicated.

The operations of the timer according to the invention will now be explained in connection with the diagrammatic illustration of FIG. 2. A coupling disc 20 rotates synchronously with the hour wheel 2 of the timer, said coupling disc being provided with a cutout 21. Simultaneously with the turning of the pointer 5 for the end of the cooking period, a clutch jaw 22 is by means of a differential turned to the same extent. Through the intervention of the outer wheel 23 of a planetary gear transmission, the cooking period is set while the outer wheel is turned in the direction of the arrow 24. A cam switch 25 cooperating with a groove 26 provided at the circumference of the outer wheel 23 serves for controlling the electric functions of the kitchen stove. The numbering provided on the outer wheel 23 is in this figure shown merely for facilitating the understanding.

There will now be explained the operation of the timer for a freely selected example. It may be assumed that at the time of day shown in FIG. 1, namely 4:48 PM, the timer is started and the end of the cooking period is to be set for 7 PM while the cooking period proper should be one hour. By means of the setting knob 6 the indicating pointer 5 and together with the latter the clutch jaw 22 is set for the time 7 PM (position 22' in FIG. 2). Thereupon the outer wheel 23 is by means of the knob 9 turned in the direction of the arrow 24 by one hour which means that the number one on the outer wheel 23 occupies the position where previously the number 12 had been. In view of this turning movement, through the intervention of the set differential, the coupling jaw 22 is turned back from its position 22' by a corresponding angle to the position 22" and now indicates the start of the cooking period. By turning the outer wheel 23, the release lever 25 was also lifted out of the groove 26.

With progressing time, the clutch disc 20 with the recess 21 moves in clockwise direction and eventually reaches the time 6 PM. At this time, the clutch jaw 22 which occupies the position 22" drops into the recess 21 and is by means of the clutch disc 20 positively taken along. Due to the dropping of the clutch jaw 22 into the cutout 21, simultaneously the current supply to the kitchen stove is turned on. In view of the fact that the clutch jaw 22 is moved, simultaneously through the intervention of the set differential also the outer wheel 23 is turned counter to the direction of the arrow 24 until the time of 7 PM has been reached. At this time, the release lever 25 drops back into the groove 26 and thus turns off the current supply to the stove. Furthermore the clutch jaw 22 is again lifted out of the cutout 21.

The mechanical construction of the timer will be evident from FIG. 3. The shafts on which the knobs 6-9 referred to in connection with FIG. 1 are arranged are designated with the reference numerals 6'-9'. The remaining structural elements referred to and discussed in FIGS. 1 and 2 are in FIG. 3 designated with the same reference numerals as in FIGS. 1 and 2. The gear train for setting a particularly short cooking time by means of shaft 7' with the gear 30 has been omitted in FIG. 3 to avoid clogging up the latter and is illustrated separately in FIGS. 4 and 5.

Shaft 6' has mounted thereon a gear 31 which meshes with the gear 32. The pointer 5 for indicating the end of the cooking period is connected to the shaft 33 of gear 32 which shaft 33 forms a hollow shaft and is arranged on the shaft of the pointers 2, 3 and 4. A braking disc 35 provided with a brake liner is pressed against the gear 32 by means of two springs 34 resting against the front plate F. This braking disc exerts upon the gear 32 and thereby the pointer 5 such a braking moment that while it is possible to turn the pointer 5 manually through shaft 6', a turning of the pointer 5 by the drive of the timer will not be possible.

A gear 36 which is connected to the main shaft 37 of the planetary gear transmission meshes with the gear 32. This planetary gear transmission comprises the above-mentioned outer wheel 23 which is freely journaled on shaft 37 and has inner and outer teeth. The planetary gear transmission furthermore comprises a sun wheel 38 connected to shaft 37, and also a planetary gear wheel 39 arranged between the sun wheel 38 and the inner teeth of the outer wheel 23. Planetary gear wheel 39 is rotatably mounted on a disc 40 which latter is freely rotatable on shaft 37. Disc 40 has fixedly connected thereto the above mentioned clutch jaw 22.

Axially displaceably mounted on shaft 37 is the above mentioned clutch disc 20 with the cutout 21. This clutch disc 20 is driven through a gear 41 which is operatively connected to the drive for the timer. By means of a lever 42, the clutch disc 20 is by a force 42' pressed against the clutch jaw 22 against the thrust of a spring 43.

The setting of the pointers 2 and 3 is effected through shaft 8' and a gear 44. Shaft 9' has mounted thereon a gear 45 which on one hand meshes with the indicating disc 11 visible through a window 11' in the front plate F and intended for the cooking period and on the other hand with the outer teeth of the outer gear 23 of the planetary gear transmission.

In view of the general explanation of the operation of the timer in connection with FIG. 2, the mode of function of the arrangement of FIG. 3 will be evident. By turning the shaft 6', the pointer 5 for the end of the cooking time will be set through the intervention of the gear 31 and the gear 32. Simultaneously, the sun wheel 38 is rotated through the gear 36, and the rotation of the sun wheel 38 brings about that the planetary gear 39 rolls on the inner teeth of the outer wheel 23 of the planetary gear transmission. In this way, however, the disc 40 on which the planetary gear is journaled and thus also the clutch jaw 22 will be rotated to a corresponding extent. In conformity with the above-mentioned example of operation, it is assumed that the clutch jaw cannot drop into the cutout 21 of the clutch wheel 20. By turning the shaft 9' the setting for the cooking period is now effected. In view of this turning movement, not only the indicating disc 11 is turned through the intervention of the gear 45 but at the same time also the outer wheel 23 of the planetary gear transmission is turned through the intervention of the outer teeth. Furthermore, the release lever 25 not visible in FIG. 3 is lifted out of the groove 26 (FIG. 2) and the clutch is prepared for the later coupling operation. In view of the turning of the outer wheel 23, due to the inner teeth of wheel 23, simultaneously also the planetary gear wheel 39 is rotated and rolls on the inner teeth. In order to assure that the setting movement of shaft 9' acts through the outer wheel 23 fully upon the planetary wheel 39, it is necessary that the sun wheel 38 is braked fast. This is effected by means of the braking disc 35 and the gears 32 and 36. By means of the outer wheel 23, the planetary gear wheel is rotated in a direction opposite to the direction of rotation when the end of the cooking period is set. Consequently, disc 40 with the clutch jaw 22 is turned back by a step in conformity with the set cooking period.

The drive for the timer drives also the gear 41 as mentioned above so that the clutch wheel 20 will rotate synchronously with the expiring time. As soon as the clutch jaw 22 faces the cutout 21, the clutch wheel 20 due to the pressure exerted by the relief lever 42 is displaced against the thrust of the spring 43 and will when turned further positively engage and move the clutch jaw 22 and disc 40. The planetary gear wheel will in view of the movement of the disc 40 continue to roll on the inner teeth of the outer wheel 23 while the sun wheel 38 remains braked fast and now turns back the indicating disc 11 through the intervention of the outer wheel 23 and the gear 45. When eventually the cooking time has ended, the relief lever 25 drops into the groove 26 on the outer wheel 23 (FIG. 2) and simultaneously brings about a return pivoting of the lever 42 and makes the force ineffective in the direction of the arrow 42'. The clutch wheel will thereby in view of the spring pressure 43 be displaced axially and will again occupy its end position while not being engaged by the clutch jaw 22.

The setting of a short cooking period will be evident from FIGS. 4 and 5. The indicating disc 10 which is provided with numbers and which is visible from the outside through a window 10' in the front plate F meshes with the gear 30 connected to the hollow shaft 7'. Connected to the shaft 50 of disc 10 is a gear 51 and a cam disc 52. The gear 51 meshes with a gear 53 which is freely rotatable on a shaft 54. This gear 53 through a clutch liner 55 cooperates with a disc 56 connected to shaft 54. For purposes of producing the necessary pressure, there is provided a spring 57 which is coaxially arranged with shaft 54 and rests against a disc 58 connected to the shaft 54. A nose 61' of a lever 61 pivotable about a shaft 60 cooperates with a groove 59 in the cam disc 52. Lever 61 is under the influence of a force acting in the direction indicated by the arrow 62. The free end of lever 61 is provided with a member 63 which is adapted to hit against a bell 64.

The gear 51 is within the range between the teeth 51' and 51" free from teeth to disengage the timer for setting a short cooking period from the shaft 54 which is driven by the drive for the timer when no short cooking period has been set. The clutch on the shaft 54 serves for making possible the setting of a very short cooking period via shaft 7' without simultaneously damaging the drive running in the opposite direction.

The setting of a very short cooking period is effected in such a way that the shaft 7" and therefore through gear 30 also the indicating disc 10 is turned in a corresponding manner. Simultaneously the gear 51 and the cam disc 52 are turned. Due to this turning movement, the lever 61 with its nose 61' is lifted out of the groove 59 of the cam disc 52 and simultaneously the teeth of gear 51 are brought into meshing engagement with the gear 53. If now the shaft 7' is relieved, the drive for the timer will through the intervention of gear 53 bring about that the gear 51 and the cam disc 52 as well as the indicating disc 10 turn in a direction opposite to the setting direction. As soon as the gear 53 leaves the effective range of the teeth at 51', the nose of lever 61 drops into groove 59 and simultaneously the member 63 hits against the bell 64.

While the present invention has been described in connection with a timer for setting a short cooking period operating in such a way that the member 63 hits against the bell 64, it is, of course, obvious that the movement of the lever 61 may also actuate another indicating device as, for instance, an electric switch which in its turn makes effective a bell or a buzzer for a desired period of time. Parts relationship of the structures identified by the foregoing reference numerals can be seen more readily in FIG. 6.

It is, of course, also to be understood that the present invention is by no means limited to the particular showing in the drawings but also comprises any modifications within the scope of the appended claims.

Claims

What is claimed is:

1. A timer mechanism, especially for use with appliances such as cooking stoves, comprising: a frame with a clock, first manual means for adjusting the end of a time period with a pointer, second manual means in coaxial relation to the first manual means for adjusting a short-time period, third manual means for adjusting the time, fourth manual means in coaxial relation to that third manual means for adjusting a selected time period which is to end at the time indicated by the pointer, the second manual means being mechanically connected with a first dial for indicating the short time period and the fourth manual means being mechanically connected with a second dial indicating the said time period, the said clock having a face and hands, a tubular shaft telescoping the shafts for said hands, the said pointer being mounted on said tubular shaft and indicating the end of the selected time period on said clock face, a clutch having a first disc driven by the driven shaft means of the clock and also having a second disc coaxial with said first disc, a spring urging said discs apart and clutch actuating means operable for resiliently urging said discs toward each other, clutch elements on said discs engageable only when in registration and said clutch discs are urged toward each other by said clutch actuating means, a control arm biased toward a first position and having a second position and said positions corresponding respectively to appliance power-off and appliance power-on, a rotatable cam engaging said arm and permitting said arm to move to said first position thereof in only one rotated position of said cam, means making said clutch actuating means ineffective in said one position of said arm, and a three element planetary gear drive having a first element connected to said second disc and a second element connected to said pointer and to said first manual means and a third element connected to said cam and to said second dial and to said fourth manual means.

2. A timer mechanism according to claim 1 which includes a clock in said frame having a face and hands, and a tubular shaft telescoping the shafts for said hands, said pointer being mounted on said tubular shaft and indicating the end of the selected time period on said clock face.

3. A timer mechanism according to claim 2, in which said frame has a front portion, said clock face and first dial being observable from front of said frame, said first and fourth manual means comprising first and second knobs respectively at the front portion of said frame.

4. A timer mechanism according to claim 3, a said second manual means being in the form of a second knob connected to said first dial for rotation thereof, timer further includes friction drive means for connecting said first dial with said timer driven shaft means, said first dial being disengaged from said friction drive means in one adjusted position only of the first dial, and signal means actuated by said first dial in response to movement thereof into said one position.

5. A timer mechanism according to claim 4, wherein said third manual means includes a third knob for adjusting said clock hands, said first and second knobs being arranged in coaxially relation at said front panel, and said second and third knobs being arranged in coaxial relation at said front panel in spaced relation to said first and third knobs.

6. A timer mechanism according to claim 5, in which said frame has a front panel with a window formed therein for said clock face and with apertures therein through which marginal regions of said first and second dials are visible.

7. A timer mechanism according to claim 6, in which said first and second dials have gear teeth, and gears meshing with said gear teeth and connected to the respective knobs.

8. A timer mechanism according to claim 6, in which the first and second dials are moveable by the respective knobs therefor away from a zero position into position to indicate respective time periods and are moved in the direction of decreasing time display by said timer driven shaft means.

9. A timer mechanism according to claim 8, in which the said first and second dials and the respective viewing apertures therefor are adjacent the respective knobs.

10. A timer mechanism according to claim 4, in which coaxial ones of said knobs are mounted on telescoping rotary shafts.

11. A timer mechanism according to claim 6, in which said first element of said planetary gear drive is the planet gear and a shaft mounted on said second disc rotatably supports said planet gear, said second element comprising the sun gear and means connecting the sun gear to said pointer and said first manual means, said third element comprising the ring gear, and means connecting said ring gear to said cam and to said first dial and to said second manual means.

12. A timer mechanism according to claim 11, in which said cam is coaxial with and mounted on said ring gear.

13. A timer mechanism according to claim 11, in which said clutch elements comprise a hole in one of said discs and a projection on the other of said discs receivable in said hole.

14. A timer mechanism according to claim 12, in which said cam is circular with a single peripheral notch therein, said control arm having a follower bearing on the periphery of said cam and receivable in said notch.

15. A timer mechanism according to claim 14, in which the resistance offered to rotation of said pointer and sun gear by said friction means is adequate to prevent rotation of said sun gear when said planetary gear is driven about the sun gear by rotation of said second disc and also when said ring gear is rotated by said second manual means.