US2301942A

US2301942A - Timing mechanism

Info

Publication number: US2301942A
Application number: US384719A
Authority: US
Inventors: William P Gallagher
Original assignee: International Register Co
Current assignee: International Register Co
Priority date: 1941-03-22
Filing date: 1941-03-22
Publication date: 1942-11-17
Anticipated expiration: 1959-11-17

Description

Nov. 17, 1942. w P, GALLAGHER 2,301,942

TIMING MECHANISM Filed March 22, 1941 3 Sheets-Sheet l Nov. '17, 1942. w. P. GALLAGHER TIMING MECHANISM Filed March 22, 1941 3 SheetsSheet 3 Z6 275552 #2 2 GE [Jay/Lew Patented Nov. 17, 1942 UNlTED STATES PATENT OFF-ICE THVHNG MECHANISM William P. Gallagher, Chicago, 111., assignor to International Register Company, Chicago, 111., a corporation of Illinois r Application March 22, 1941, Serial No. 384,719

20 Claims. (01. 20039) The present invention relates to timing mechanism, and more particularly to time controlled switches, time controlled valves and the like. This application embodies improvements upon the electrical timing apparatus disclosed in the copending application of myself and Alfred W. Gardes, Serial No. 319,010, filed February 15, 1940. Although not essentially limited thereto, the timing mechanism of this application and of said copending application has its principal use on electric ranges and the like, which are adapted to be set by the housewife to automatically control the starting and stopping of a cooking operation.

One ofthe principal objects of the invention is to simplify the operation of the timer, so as to avoid confusion and mistakes by the housewife in the use of the device. The greater the likelihood of mistakes in the use of an automatic timer, the greater becomes its sales resistance, and the greater becomes its maintenance cost because of having to make service calls to explain such. mistakes. The improved timer herein disclosed preferably has one adjustment which is set corresponding to the time when the cooking operation is to stop, and another adjustment which is set corresponding to the'number of hours or fraction of an hour required for the performance of the cooking operation. This is the preferred arrangement because it requires no arithmetical computation by the housewife in order to insure that the cookin operation will be completed at the desired hour, since it is only necessary for her to set one adjustment corresponding to that hour, and to set the other adjustment corresponding to the prescribed length of time for cooking, and everything is then in readiness without her having to do any computing in making these settings. In the preferred embodiment of the invention herein disclosed, these two adjustments are grouped concentrically with respect to the clock dial of the timer. This simplifies the making of the adjustments because the two adjustments are thus directly related by such concentric grouping; also, because the setting f the stop cooking adjustment can then be made directly with reference to the hour and fractional hour markings on the clock dial. These clock dial markings are large and widely spaced, and the above adjustments can therefore be made more easily and more accurately than when small separate dials are used. The above described arrangement of the stop cooking and start cooking closed in the aforementioned copending application.

The principal feature of the present application resides in combining with the above time-setting adjustments an improved manually actuated control by which the apparatus is placed under the above described automatic time sequence at the start of a cooking cycle, and by which the apparatus is also restored to a normal condition at the end of the cooking cycle. Moreover, this manually actuated control permits the housewife to reset the apparatus in the event that she has made a mistake either in setting up the stop cooking time or in setting up the cooking hours time. The rectification of such a mistake may be a source of confusion to her, particularly if she has proceeded to the next step of placing the timer under automatic time control before discovering the mistake. Under such circumstances, it is frequently less confusing to her if she can go back and. start all over again. In my improved construction of timer herein disclosed, this can be accomplished very easily and with no confusion by merely rotating th manually actuated control knob back to its normal position.

Another feature of this manually actuated control is a simple rotary motion of the control, combined with an improved sequence of its positions or steps. In the preferred embodiment herein disclosed, this sequence of positions or steps is as follows: (1) A closed-circuit normal position; (2) an open circuit set position which sets the device under automatic control; (3) a closed-circuit automatic cooking position; and (4) an open circuit automatic stop cooking position. This sequence of positions in the rotary motion of the control is advantageous because it follows the order of the actual steps which take place in the proper use of the timer, and because it also indicates more clearly to the housewife that if she makes a mistake in setting up the automatic time cycle she should rotate the control back to a starting point in order to start over again.

Another feature of the invention resides in providing improved visual indicating means for giving an immediately understandable indication whenever the timer is not in its' normal closed circuit position. This greatly simplifies the use of the timer, and avoids many service calls in those adjustments in concentrically grouped relation to g the clock dial constitutes one of the features disual switch on th range by which the housewife situations where the housewife is endeavoring to operate the range under manual control while the timer stands in the position of automatic control. The circuit controlling switch of the timer is usually connected in series with a separate mancan manually control the heating element when she does not desire automatic time control. However, in order that this conventional manual switch be efiective to energize the heating element, the switch of the automatic timer must stand in a closed circuit position. Frequently, the automatic timer is not immediately reset to its normal closed circuit position after the completlon of a cooking operation, but is allowed to stand in the open circuit position to which it has moved automatically in the performance of the final stop-cooking step of the automatic cycle. The housewife will sometimes fail to note that the timer has not been restored to its normal closed circuit position when she is endeavoring to energize the heating element through the manual switch, and will conclude that the heating element or the range is defective, requiring the attendance of a service man. My improved visual indicating means greatly reduces the frequency, expense and inconvenience of these service calls.

Another advantage gained by my invention is a simplified construction and a reduced cost of manufacturing the timer. This simplified construction is also characterized by a reduced number of parts likely to get out of order.

Other features, advantages and objects of the invention will appear from the following detail description of one preferred embodiment thereof. In the accompanying drawings illustrating such embodiment:

Figure l is the front elevational view of the timer enclosed within a suitable housing, or disposed behind a suitable panel;

Figure 2 is a transverse sectional view through the timer, taken approximately on the plane of the line 22 of Figure 1;

Figure 3 is a sectional view at right angles to Figure 2, represented approximately by the section plane 33 on Figure 2;

Figures 4, 5, 6 and 7 are fragmentary diagrammatic views showing the successive steps or positions in the motion of the switch actuating cam and manually actuated control of the timer;

Figure 8 is a circuit diagram of the timer; and

Figure 9 is a detail view of the detent spring.

A considerable part of the construction shown in this application follows in main essentials the construction shown in the aforementioned copending application of myself and Alfred W. Gardes, Serial No. 319,010. Accordingly, attention is directed to said copending application for certain parts of the construction not described in minute detail in this application.

Referring to Figure 1 of the present drawings, the timer is shown as being housed in a casing or housing 2| of box-like form comprising a front wall and four side walls extending rearwardly therefrom; it being understood, however, that in some situations the timer might merely be set back of a panel or false front built into the cooking range. The front wall of said housing or panel has a large central opening therein through which appears the dial 22 of the electric clock, this dial having the usual hour and fractional hour markings 23, and the hour and

minute hands

24 and 25 respectively. A resetting knob 26 extends forwardly from the front side of the cover glass 21, this knob being operative to reset the hands of the clock if the clock motor should stop by reason of current failure or any other cause.

Concentric with the clock dial are the two rotatable adjusting

members

28 and 29 which are settable to different positions to predetermine the starting and stopping of the cooking operation. The adjustable member 28 is preferably in the form of a continuous ring surrounding the clock dial and bearing the notation "Stop cooking." The ring is formed with a forwardly extending actuating knob 28, preferably located adjacent to the above notation. Extending inwardly from the ring in registration with this knob is a pointer formation 28" which is adapted to register with the hour and fractional hour markings 23 on the clock dial in the different angular positions to which the adjusting ring is moved. The other adjusting member 29 may likewise be in the form of a continuous ring, surrounding the ring 28. However, in the preferred construction shown, this member is in the form of an arm having a knob or handle extremity 29 which is of substantially the same size and shape as the knob 28 on the ring 28. An inwardly extending pointer formation 29" on the adjustable member 29 overlies a portion of the adjusting ring 28, and is adapted to register with a second series of hour and fractional hour markings ll provided on the adjusting ring 28. These latter marks designate the cooking hours, i. e., the length of time that the cooking operation is to continue, the adjusting member 29 being movable to different ones of these marks for adjusting the length of the cooking time period. In adjusting the

members

28 and 29 to different times, the Stop cooking" ring is first adjusted to the time when it is desired to have the cooking operation completed. In Figure 1 this is represented as four oclock. After adjusting this member, the other adjusting member 29 is now moved into registration with the marking 3| which corresponds with the length of time that the cooking operation is to continue. In the drawings, this is represented as being two hours. Thus, the cooking operation automatically starts at two oclock and stops at four o'clock. It will be noted that in each of the set positions of the adjusting member 29, the pointer formation 29 of this member points to the particular marking 23 of the clock dial which denotes the start-cooking time.

Spaced to the right of the clock dial is the aforementioned manually actuated control which comprises a rearwardly extending oscillatable control shaft 33 to the front end of which is secured the control knob 33'. This control shaft and knob have angular movement into each one of the four positions previously described. Projecting from the knob is an extension portion 33" which serves as a pointer portion and also as a cover portion for indicating each of the four positions into which the shaft and the knob are movable. Marked on the housing or panel 2| is a visual indicator 34, such as a brightly colored dot or target area, preferably a bright red to be as conspicuous as possible. When the control shaft and knob are in the normal closed circuit position of the timer, as indicated in dotted lines, the pointer or cover portion 33" of the knob lies directly over the visual indicating element 34 so that this element is completely obscured from view. However, as soon as the knob is rotated clockwise to its second position, which is the open circuit time control position, the red indicator area 34 is uncovered, and remains uncovered while the knob moves successively into its third and fourth positions, and continuously remains uncovered until the knob is moved back in a counterclockwise direction to said first position, corresponding to the closed circuit manual control position. The indicator mark 34 is adequate to meet most requirements without any other designation of the different positions of the knob, but, if desired, this indicator marking may be supplemented with an Oif" marking 35 and a "Set marking 38, the latter designating the set position into which the knob is moved for the purpose of placing the timer under automatic control.

Disposed to the other side of the clock dial is the interval timer knob 44. The periphery of this knob is marked with minute graduations 44, ranging say from zero minutes to sixty minutes. These marks are adapted to be brought into registration with an index pointer 45 on the casing when it is desired that the interval timer should sound an audible signal upon the lapse of a selected time interval, as described in deatively long spur pinion I8. Said gears I1 and 18 are mounted on a vertical shaft "which has its lower end supported in a bracket portion extending from the lower frame plate: 48',- ari'd which has its upper end supported in the upper frame plate 41''. {The relatively long pinion 18 transmits rotation ma spur gear 8! which is fixed to the lower end of the hour hand sleeve 18 and which tail in said aforementioned copending application. A later improvement of this interval time also forms the subject matter of. my copending application Serial No. 406,918, filed August 14,

Referring now to Figures 2 and 3, the working parts of the mechanism are supported in a frame structure comprising upper and lower frame plates 41 and 48 which are joined together in spaced relation by suitable screws and spacing posts 55. Mounted in the left hand side of the frame structure is the electric motor 61 which drives the clock and other driven parts of the mechanism. In almost all instances, this electric motor will be a synchronous alternating current motor of any preferred construction, such as are commonly employed in electric clocks and the like. It will of course be understood that if a frequency regulated alternating current is not available for operating such a motor, the latter' might be substituted by conventional spring driven clock mechanism, or by an accurately reg ulated electric motor of another type. Extending downwardly from reduction gearing within the base of the motor unit BI is a pinion shaft 62 carrying pinion teeth 63 which mesh with an idler gear 64 supported on the lower portion of a vertically disposed toothed shaft 66 having gear teeth 51 in its lower end, and gear teeth 68 in its upper end, This toothed shaft has its lower end journaled in a plate or bracket 85 and its upper end journaled in the upper frame plate 41. The gear teeth 68 formed in the upper portion of the shaft 61 are arranged to drive the interval timer.

The aforementioned teeth 61 in the lower portion of the shaft drive a large spur gear H which is disposed at the lower end of the clock assembly. Such gear is adapted to have a frictional clutch drive with the axial shaft or spindle 72 which carries the minute hand at its upper end. The extremity of this minute hand shaft extends out through an opening in the cover glass 21 of the clock dial and has the resetting knob 26 secured thereto. A pinion i3 is fixedly staked to the minute hand shaft 12, and has a hub portion extending downwardly through the large gear H, the lower end of this hub portion having a spring armed spider 14 fixedly secured thereto. The large gear "H is capable of frictional rotation on the pinion hub, between the body of the pinion and the spider 14, the operating relation being such that the gear 1| normally transmits timed rotation to the minute hand shaft 12, but said minute hand shaft is capable of rotation relatively to said gear in the operation of setting the clock hands through manipulation of the resetting knob 28. The hour hand 24 of the clock is secured to the upper end of an transmits one complete rotation to the hour hand every twelve hours. Said long spur gear 18 also transmits'this same identical rate of rotation to a time driven roller which rotates through a circular pathexternally of the hour hand sleeve 18,

as I shall presently describe.

The clock assembly comprising the dial, minute hand shaft, and hour hand sleeve, is supported by a vertical, stationary supporting sleeve 83 which is rigidly anchored to the lower frame plate 48. For example, a radial mounting flange 84 projects outwardly from the lower portion of the sleeve for abutment against the top surface of the frame plate, and a reduced lower portion of said sleeve extends through an aperture in the frame plate and is peened over to rigidly stake the supporting sleeve to the plate. The minute hand shaft 12 and the hour hand sleeve I6 extend upwardly through the supporting sleeve 83. For mounting the clock dial 22 on said supporting sleeve, the dial is carried by a plate 81 having a central aperture which fits down over the upper end of the sleeve. Below the plate 81 is a bushing or collar 88 formed with an outwardly extending lower flange, this bushing or collar having its lower face seating against an annular shoulder formed around the upper portion of the supporting sleeve 83. A nut 9i screws down over an external thread formed on the upper end of the supporting sleeve, the dial supporting plate being clamped rigidly between the nut Bi and the bushing or collar 88. The cover glass 21 extending over the clock dial has any suitable attachment to the dial and to the plate 81 by a peripheral confining ring 94.

The adjustable Stop cooking ring 28 is anchored to a disk which has a central bearing aperture engaging over the bearing bushing 88 for free rotation thereon. The other adjusting member 29, which predetermines the number of hours that the cooking operation is to continue, is carried by an arm 96 which extends downwardly and inwardly below the disk 95, and which-has an alpertured central portion rotatably engaging over the bearing bushing 88 below the rotatable disk 95. Extending downwardly from the disk 95 is a pointed cam 98, it being evident that this cam will assume different positions of adjustment around the axis of the assembly as the Stop cooking ring 28 is moved to its different points of adjustment. In similar fashion, a pointed cam 99 projects downwardly from the arm 95, whereby this cam assumes different angular positions of adjustment as the outer adjusting member 29 is moved to different positions for adjusting the cooking interval. Both cams extend down through a relatively large circular opening formed within the upper frame plate 41,

and the cam 39 rotates in a path of movement which is just inside the path of movement of the cam 98. The cams are independently adjustable. but the arm 96 will engage against the cam 98 if the housewife should accidentally attempt to make an erroneous setting with the long cam 88 in position to be engaged by the time driven roller before said roller engages the short cam 99. Moreover, the cooking hours knob 25 will not clear the stop cooking knob 28, so as to further prevent the possibility of erroneous setting of the adjustments. In the normal operation, first the short cam 99 and then the long cam 98 are engaged in that sequence by the aforementioned roller II, which revolves continuously around the outer side of the assembly. Said roller is rotatably mounted on a stud I02 projecting radially outwardly from a time driven shifter sleeve I03 which is mounted for rotation and reciprocation on the outside of the supporting sleeve 83. A gear I04 is rigidly secured to the lower end of the sleeve I03, this gear having the same diametral pitch as the gear 8i and also meshing with the relatively long gear 18 which drives said gear 8|. Thus, sleeve I03 and roller IOI rotate at the same speed as the hour hand 24, i. e., one complete revolution in twelve hours, the gear I04 remaining in continuous mesh with the relatively long gear 18 during axialreciprocation of the sleeve I03 along the supporting sleeve 83. Downward reciprocation of the roller ml and sleeve I03 occurs each time that the roller IOI encounters the cams 88 and 98. As previously described, the two cams are of unequal length in a downward direction, the cooking hours cam 99 being relatively short and causing the sleeve I03 to move down a relatively short distance, whereas the stop cooking cam 98 is relatively longer, and causes the sleeve I03 to move down a greater distance.

An annular groove I05 is formed in the lower portion of the shifter sleeve I03, whereby the shifting movement of the sleeve is transmitted to a time controlled tripping lever I01. A laterally extending arm of said lever is formed with a rounded end portion I08 which engages in the annular groove I06, for transmitting reciprocal motion of the shifter sleeve to the lever. The lower end of the lever I01 is pivotally supported by the lower frame plate 48 in any suitable manner, such as by extending the lever down through a slot in the plate and by having studs or protuberances III projecting through the lever and engaging the top and bottom surfaces of the plate. A spring bias is continuously exerted against the lever tending to swing it to the right (Figure 2), such being effected by a wire II4 coiled about a stud H5, and having one end anchored to the frame plate 41 and its other end engaging in an aperture in the lever I01. The upper extremity of the bell crank tripping lever I01 is arranged to oscillate back and forth in a long narrow guide slot II8 punched in the upper frame plate 41, this guide slot sustaining the lever against the lateral stresses exerted against the lever by the spring impelled control member which is now to be described.

This control member comprises the aforementioned control shaft 33 and control knob 33', with which are combined a multiple stop plate IIS and a switch actuating cam I2I, both of which are mounted directly on the control shaft 33 to have angular movement therewith. The multiple stop plate II9 comprises three successivc stops I22, I23 and I24 adapted to engage successively against the side surface of the tripping lever I01 as the control shaft 33 is angularly advanced, step by step, in a clockwise direction. The stop shoulder I23 projects outwardly to a greater radius than the stop shoulder I22, and the stop I24 is in the form of a roller carried on an arm I24, this arm and roller projecting outwardly to a greater radius than the stop shoulder I23, whereby as the tripping lever I81 is retracted in steps, it will successively release the stop shoulder I22 and then the stop shoulder I23, for producing a step-by-step advancing movement of the control shaft 33. In the final step of advancing movement, the roller I 24 comes up against the side of the tripping lever I01, which concludes the rotary motion of the control shaft 33 in this clockwise direction. The shaft 33 is urged constantly in this direction of rotation by a helical torsion spring I28 which is coiled about the control shaft directly below the multiple stop plate II! (Figure 2). One end of this torsion spring bears against a lug I21 extending from the stop plate IIS, and the other end of the spring bears against an adjacent spacing post 55.

The roller I24 carried by the arm I26 of the rotative stop plate H3 is adapted to cooperate wtih a detent spring I 28 so as to function as a releasable detent when the control shaft 33 and knob 33' are in the closed-circuit normal position illustrated in dotted lines in Figure 1 and in full lines in Figure 4. The fixed end of the detent spring I28 is secured by screws or rivets I29 to a lug I3I extending downwardly from the upper frame plate 41. Said detent spring comprises a main arm portion I28 a reversely extending finger portion I28, and a raised hump I28 formed in the length of said reverse finger portion. "The forward slope of the hump I28 is relatively abrupt for establishing detent cooperation with the roller I24, while the reverse slope of the hump is relatively gradual so as to enable the roller to cam the hump downwardly out of the way when the roller is restored back to its normal position in engagement with the abrupt forward slope. The strength of the detent spring I28 has to be sufficient to be able to hold the roller I24 in the closed-circuit normal position of the control member (Figure 4), against the rotative force of the torsion spring I28. However, this detent spring I28 must also be sufficiently yieldable to enable the housewife to turn the control knob 33' and force the roller I24 past the hump I28 for moving the control device from the closed circuit normal position of Figure 4 to the open circuit Set" position of Figure 5. I have found it advantageous to construct the detent spring I28 in the particular manner above described. In such construction, when the roller I24 is thus manually forced from its detent or restrained position to its released position the reverse finger portion I28 first flexes so as to change the angle of the relatively abrupt forward surface of the hump I28 and then the entire detent spring flexes for accommodating bodily displacement of the hump out of the path of the roller. This change of angle of the hump I2II relatively to the main arm portion I28 facilitates release of the roller from the hump, even though the detent spring has substantial strength for resisting the torsion strength of the coiled spring I26.

The switch actuating cam I 2| is mounted on the lower portion of the control shaft 33 and is arranged to actuate the switch mechanism which is indicated generally at I30. The cam comprises two diametrically opposite cam lobes I2I' set at one angle, and another two diametrically opposite cam lobes I2I" set at another angle. These cooperating pairs or cam lobes are brought to bear successively against the inner surfaces of two parallel contact springs I3I, I3I'. The contact springs are disposed on opposite sides of the switch actuating cam I2I so that as this cam rotates through its successive angular steps first one pair of cam lobes spreads the contact springs outwardly to open circuit position, followed by inward flexing of the contact springs back to their normal closed circuit position, and followed still further by the other pair of cam lobes again spreading the contact springs outwardly into their open circuit position. The contact springs are assembled upon an insulating housing structure built up of two blocks or strips of insulating material I34 and I35. The anchored ends of the contact springs are secured by screws or rivets I36 to these insulating blocks. The flexing ends of the contact springs carry contacts I31, I31 which are normally in engagement with stationary contacts I 38, I38 mounted in the insulating blocks. These blocks may be secured in any suitable manner to the frame structure of the timer, such as by securing them under an upwardly oifset portion of the lower frame plate 48. The two contact springs might control separate circuits where the time switch is employed in a situation where there are two circuits to be thus controlled, although in the average situation these two contact springs and their associated contacts will be connected in series to control a single circuit, as shown in Figure 8. As another alternative arrangement for a single circuit, the two contact springs might be connected in parallel, whereby one contact spring will be sure to close the circuit even if dust, burned points or other abnormal conditions prevent the other contact spring from moving to closed circuit position. Where a single circuit is under the control of the timer in an ordinary electric range, it is usually the circuit of the oven heating element. Figure 8 is a fragmentary diagram of such a circuit, showing the contact springs I3I, I3I in series in the two sides of such' single circuit. It will be understood that a conventional manually actuated switch I40 is also connected in series with the switch I30 of the present timer, in order that the particular heating element I42 which is to be controlled by .the timer can also be controlled manually by switch I40 when automatic operation is not desired. When this. heating element I42 thus controlled by both the timer switch I30 and manual switch I40 is the heating element of the oven, such heating element may be further controlled by an automatic thermostatic switch I4I, which will govern, at a setting determined by the housewife,

the cooking temperature within the oven.

Referring now to the operation of the apparatus, the timer switch normally stands in the closed circuit position illustrated in Figure 4 so that the energization of the heating element I42 can be turned on or off through the medium of the manual switch I40. At this time, the red target area 34 is covered by the pointer extension 33" of the control knob 33'. Assuming now that it is desired to have the timer operate through an automatic cycle, say for starting a slow cooking operation which is to end at four o'clock and which is to be of two hours duration, as mentioned above. ,gor the performance of this time cycle, the stop cooking adjustment 20 is set at four o'clock on the clock dial 22 and the cooking hours adjustment is set at the numeral 2" on the scale 3|, both as indicated in Figure l. Thereupon, the control knob 33" is rotated in a clockwise direction, out of the releasable detent position shown in Figure 4, into the Set position illustrated in Figure 5. The settting operation is now completed, and the timer is in readiness to go through its automatic cycle at the prescribed time. This operation of setting up the times may, of course, be performed in the moming or at any other time not more than twelve hours preceding the time when the cooking operation is to start. In this set position of the parts, the multiple stop plate H9 will occupy the position illustrated in Figure 5, with its first stop shoulder I22 abutting against the trip lever I01. In this position of the control member 33, the main switch cam I 2| has its diametrically opposite lobes I2 I bearing against the contact springs I3I, I3I' for holding the latter in their open circuit positions. As the time approaches for starting the cooking operation, the continuously driven roller IOI encounters the short cam 90, which has an angular setting predetermined by the position of the cooking hours adjustment 29. The roller rides down the slope of said cam, thereby thrusting the sleeve I03 downwardly and imparting a retractive movement to the tripping lever I01. Substantially at the time when the roller reaches the peak of the cam 99, the tripping lever has been retracted just enough to clear the first stop shoulder I22 of the stop plate H0. Instantly upon the tripping of this first stop shoulder, the control assembly rotates quickly through a one step advancement, bringing the second stop shoulder I23 up against the tripping lever I 01, owing to the fact that this second stop shoulder projects outwardly to a greater distance than the first stop shoulder. This position is illustrated in Figure 6. The one step advancement of the control member rotates the cam lobes I2I' out of engagement with the contact springs I3I, I3I', so that said contact springs immediately flex inwardly into circuit closing position. This completes the circuit to the heating element I42, the manually actuated switch I40 having been previously set in its on position. As the time approaches for stopping the cooking operation, the continued time driven motion of the roller IOI finally brings it into engagement with the relatively long cam 98. Substantially at the time that the roller IOI reaches the peak of the cam 90, the tripping lever I 01 has been retracted sufficiently far to clear the second stop shoulder I23 of the stop plate IIII. Hence, the control assembly is permitted to quickly rotate through a second step of advancing movement, thus bringing 'the' detent roller I24 up against the side of the tripping lever I01. This third step of advancing movement of the switch cam I2I brings the cam lobes I2I" into engagement with the contact springs I3I, I3I', thereby flexing the contact springs outwardly to open circuit position. Thus, energization of the heating element I42 is interrupted at the time previously set for stopping the cooking operation. This position of the parts is illustrated in Figure 7. In each of the three last described positions of the control member .(Figures 5, 6 and 7) the control knob 33'. has moved through positions which leave the red target area 34 continuously exposed. Hence, in each of these positions, the exposure of the red target area functions as a continuous indication that the timer switch is not in its normal closed circuit position. At the conclusion of the automatic time cycle, after the cooking operation has been interrupted, the housewife will usually remember to place the time switch back in its normal, closed circuit position, but if she should fail to do so at this time the continuous exposure of the red target area 34 will serve as a reminder that the timer switch is not in its normal closed circuit position. The restoration of the timer switch back to its normal closed circuit position, is, of course, accomplished by merely rotating the control knob 33' backwardly in a counterclock-,

wise direction to the position illustrated in Figure 1, where the pointer extension 33" covers the red target area 34.

Should the housewife make any mistake in setting up the stop cooking time or the cooking hours time, and then turn the control knob to the Set position of Figure 5 before realizing that a mistake had been made, all she has to do to correct the mistake, or start all over again without upsetting the time cycle, is to turn the control knob 33' back to the normal closed circuit position illustrated in Figure 4. This enables either or both of the time adjustments to be shifted to different positions without upsetting the time cycle of the device.

In this same regard, it should also be noted that the housewife can turn the control knob 33' from the cooking position of Figure 6 back to the normal position of Figure 4 any time that she desires, without having to perform any preliminary manipulation of the time setting mem- 1',

bers 2B and 29 for releasing said control knob. Thus, it through any change of plans, after a time cycle has been set or is occurring, she desires to take the control of the switch away from the automatic mechanism and place it under manual control, she can quickly and easily restore the knob 33 from either of the positions shown in Figures 5 and 6 back to the normal position shown in Figure 4, without having to perform any releasing manipulation of the

time setting members

28 and 29.

In the event that the housewife wishes to have the cooking operation start immediately, say at four oclock, and to continue for a definite period, say two hours, she sets the stop-cooking pointer 28" at the six o'clock marking on the clock dial 22 and moves the cooking-hours pointer 29" to the 2 mark 31 on the ring 28. Assuming that the control knob 33 is now turned to the Set position 36, or has already been turned to that position, the switch I30 immediately closes (Figure 6), the cooking operation starts at once, and continues until six oclock, whereupon. the switch automatically moves to the open position (Figure 7), and the cooking operation stops.

While I have illustrated and described what I regard to be the preferred embodiment of my invention, nevertheless it will be understood that such is merely exemplary and that numerous modifications and rearrangements may be made therein without departing from the essence of the invention.

I claim:

1. In timing apparatus of the class described, the combination of an electric switch, timing mechanism for controlling said switch, said timing mechanism being settable to different times, and control mechanism comprising a control member, spring means tending to rotate said control member through successive positions, and

means operative solely by rotational motion of said control member for placing said switch alternatively in a normal position or in a second position under the influence of said timing mechanism.

2. In timing apparatus of the class described, the combination of electric switch means having a normal position, timing mechanism for controlling said switch means, and control mechanism comprising a manually rotatable control member for said switch means, spring means biasing said control member in one direction of rotation, and means responsive to rotation of said control member in said latter direction for changing said electric switch means from said normal position to a position under the control of said timing mechanism.

3. In timing apparatus of the class described, the combination of electric switch actuating means having a normal position, automatic timing mechanism for controlling said switch actuating means, said timing mechanism being settable to different times, and control mechanism comprising a manually rotatable control member, spring means tending to rotate said control member in one direction, and means operative solely by rotational motion of said control member in said latter direction for causing said switch actuating means to shift from said normal position to a set position under the control of said automatic timing mechanism.

4. In timing apparatus of the class described, the combination of an electric switch, switch actuating means having a normal position in which said switch is closed, automatic timing mechanism for controlling said switch actuating means to automatically close and open said switch, said automatic timing mechanism being settable to establish diiierent times for the automatic closing and opening of said switch, and control mechanism comprising a control member responsive to said automatic timing mechanism but manually rotative to cause said switch actuating means to shift from said normal position to a position under the control of said automatic timing mechanism or back to said normal position independently of the operation of said automatic timing mechanism.

5. In timing apparatus of the class described, the combination of an electric switch, switch actuating means having a normal position and movable therefrom through a sequence of successive positions. automatic timing mechanism for controlling said switch actuating means, said timing mechanism being settable to dlflerent times, spring means tending to move said switch actuating means from said normal position to a second position where it is under the influence of said automatic timing mechanism, detent means for holding said switch actuating means in said normal position against the action 01' said spring means, and manually actuated control means for releasing said switch actuating means from said detent means for movement into said second position.

6. In timing apparatus of the class described, the combination of an electric switch, switch actuating means having a normal position in which said switch is closed followed by a plurality of succeeding positions in which said switch is successively opened and closed, spring means tending to rotate said switch actuating means from said normal position through said succeeding positions, timing means for controlling the motion of said switch actuating means through said succeeding positions, and control means for moving said switch actuating means from one of said succeeding positions back to said normal position.

7. In a time switch for cooking ranges and the like, the combination of clock mechanism, an electric motor for driving said clock mechanism, an electric switch for starting and stopping a cooking operation oi? the range, two separately adjustable time-setting mechanisms mounted for rotation about -a common axis and having cooperative connection with said clock mechanism and with said electric switch for approximately predetermining the duration of the cooking operation and the time of day it is to occur, control means including a control knob operative by rotary movement to place said electric switch in a normal closed-circuit position or to render said switch responsive to the automatic control of said time-setting mechanisms, and spring means tending to rotate said knob to successive positions when said knob is under the automatic control of said time-setting mechanisms, said control means being operable solely by rotation 01' said knob to place said switch in said normal closed-circuit position from any of said other positions. V

8. In an electric time switch for cooking ranges and the like, the combination of clock mechanism, an electric motor for driving said clock mechanism, an electric switch for starting and stopping a cooking operation of the range, a rotatable control member governing the position of said switch, said control member having a first position closing said switch, a second position opening said switch, a third position closing said switch, and a fourth position opening said switch, spring means tending constantly to rotate sa d control member toward said fourth position, a knob operative to rotate said control member back to said first position, and'detent means operative to hold said control member in said first position against the action of said spring means, said knob being operative through manual effort exerted thereon to release said control member from said detent means.

9. In a time switch, the combination 01! clock mechanism, an electric motor for driving said clock mechanism, an electric switch, adjustable time-setting mechanism cooperating with said clock mechanism and saidelectric switch for causing automatic operation of said switch at a set time, control means associated with said switch comprisinga manual actuating member, stationary visual indicating means for indicating when said control means has been moved out of a predetermined position, and movable means responsive to said control means for causing said visual indicating means to be obscured when said control means has been restored to said predetermined position.

10. In a time switch, the combination of clock mechanism, an electric motor for driving said clock mechanism, an electric switch, adjustable time-setting mechanism cooperating with said clock mechanism and said electric switch for causing automatic operation of said switch at a set time, control means associated with said switch comprising an operating knob movable from a normal position into three other control positions, a red target area for gi n an identical indication when said control means has been moved out of said normal position into either one of said three other control positions, and means moving with said operating knob for causing said red target area to be covered when said control means has been restored to said normal position.

11. In a time switch, the combination of clock mechanism, an electric switch, adjustable timesetting mechanism cooperating with said clock mechanism for causing automatic operation of said switch at a predetermined time, control means associated with said switch adapted for manual actuation into arid out of a normal switch closing position, spring means tending to rotate said control means out of said normal switch closing position and into succeeding control positions, and releasable detent mechanism for bolding said control means in said normal position in opposition to the action of said spring means, said detent mechanism comprising a detent hump, a relatively movable stop projection adapted to engage behind said hump, and means supporting said hump whereby in releasing said projection therefrom said hump first assumes a reduced angle to the path of said projection and is then displaced from the path of said projection.

12. In a time switch, the combination of clock mechanism, an electric switch, adjustable timesetting mechanism cooperating with said clock mechanism for causing automatic operation oi. said switch at a predetermined time, control means associated with said switch adapted for manual actuation into and out 01' a normal switch closing position, and releasable detent mechanism for holding said control means in said normal position, said detent mechanism comprising a detent hump, and a relatively movable stop projection adapted to engage behind said hump.

13. In a time switch, the combination of clock mechanism, comprising a clock dial, an electric switch, switch actuating means, time-setting mechanism for causing automatic operation of said switch actuating means at a predetermined time, said time-setting mechanism comprising indicating means rotatable concentrically of said clock dial, and control means operative by rotary movement to effect movement of said switch actuating means between a normal position and a position responsive to said time-setting mechanism.

14. In a time switch, the combination of clock mechanism, an electric switch, switch actuating means, two time-setting mechanisms associated with said clock mechanism for causing automatic operation of said switch actuating means at different predetermined times, said two time-settingmechanisms comprising separate indicating means both mounted for rotation about a common axis, and control means operative solely by rotary movement to effect shifting of said switch actuating means alternatively between a normal position and another position or positions responsive to said time-setting mechanisms.

15. In a time switch, the combination of clock mechanism, an electric switch having a normal switch closing position and a plurality of successive control positions, switch actuating means, two time-setting mechanisms associated with said clock mechanism for causing automatic operation of said switch actuating means in said successive control positions, said two timing-setting mechanisms comprising two separately settable rotatable members mounted for adjusting movement about a common axis, time-driven means connected with said clock mechanism and retatable about said common axis for cooperative engagement with said two separately settable .rotatable members, and control means operative solely by rotary movement to return said switch actuating means to said normal position from either of said successive control positions.

16. In an electric time switch for cooking ranges and the like, the combination of clock mechanism for indicating time, an electric motor for driving said clock mechanism, an electric switch for starting and stopping a cooking operation of the range, two separately adjustable timesetting mechanisms cooperating with said clock mechanism and with said electric switch for approximately predetermining the duration of the cooking operation and the time of day it is to occur, and switch control means including a control knob rotative in sequence from a closedcircuit normal position to an open-circuit set position and thence to a closed-circuit third position and finally to an open-circuit fourth position, said switch control means being operative solely by manual rotative movement of said knob to place said electric switch in said closed-circuit normal position or into said open-circuit set position, in which latter position said switch is responsive to the automatic operation of said time-setting mechanism.

17. In an electric time switch for cooking ranges and the like, the combination of clock mechanism for indicating time, an electric motor for driving said clock mechanism, an electric switch for starting and stopping a cooking operation of the range, two separately adjustable time-setting mechanisms cooperating with said clock mechanism and with said electric switch for approximately predetermining the duration of the cooking operation and the time of day it is to occur, means including a control knob operative by rotary movement to a normal position to place said electric switch in a normal closed-circuit position and operative by rotary movement to a set position to render said switch responsive to the automatic operation of Said time-setting mechanisms, spring means tending to rotate said knob from said normal position into said set position, and manually releasable detent means for holding said knob in said normal position. a

18. In timing apparatus for securing the timed operation of a device, the combination of a control member operatively arranged to govern said device, time responsive mechanism for causing automatic operation of said control member, said time responsive mechanism comprising manually actuated adjusting means for adjusting the time of such automatic operation, said control member having rotary movement into a set position where it is under the automatic control of said time responsive mechanism and also having rotary movement into a normal position where it is not under said automatic control, and manual means operative solely by rotary movement to effect the rotation of said control member from said set position to said normal position without disturbing the adjustment given said manually actuated adjusting means.

19. In a time switch of the class described, the combination of a switch, a control member operatively arranged to govern said switch, time responsive mechanism for causing automatic operation of said switch, said time responsive mechanism comprising tripping means and a plurality of stop shoulders coacting therewith, said control member having rotary movement into different set positions where it is under the automatic control of said tripping means and said plurality of stop shoulders, and also having rotary movement into a normal, switch-closing position where it is not under such automatic control, and manual means operative solely by rotary movement to effect the rotation of said control member from any one of said set positions to said normal position.

20. In an electric time switch of the class described, the combination of an electric switch, cam means for actuating said switch, a rotatable control shaft for actuating said cam means, said control shaft having a first or normal position in which said switch is closed, followed by second, third and fourth positions in which said switch is successively open, closed and open, spring means tending to rotate said shaft in a direction from said first to said fourth positions, automatic time mechanism for automatically tripping said shaft between said second, third and fourth positions, a control knob for restoring said shaft from said fourth position back to said first position, and detent mechanism for releasably holding said shaft in said first position, said detent mechanism comprising a roller swinging with said shaft, and a detent spring cooperating therewith, comprising a main resilient arm portion fixed at one end, a resilient finger portion carried by the free end of said resilient arm portion and extending substantially reversely to said arm portion, and a hump associated with said resilient finger portion, said hump having a relatively abrupt rear surface and a relatively gradual front surface, said roller engaging behind said relatively abrupt rear surface when said shaft is in its first or normal position.

WILLIAM P. GALLAGHER.