US3213695A - Interval timer and drive mechanism therefor - Google Patents

Description

1965 F. DRUSEIKIS ETAL 3,213,695

INTERVAL TIMER AND DRIVE MECHANISM THEREFOR Filed Dec. 21, 1961 4 Sheets-Sheet 1 M 6 c im -5 J 38 l O 0 I la:

a Ev??? M r U /4 z nip a v IIIIIIIILIIIIIJ I fl I 1y I U k 48 Q I r M a I ,77 I 64 "4 a MK 0 u; S i I 34 1114;;1 v //////|////y/// I2 INVENTORS FREDERICK DRUSEIKIS RALPH D. UNTERBORN BY aa'm THEIR ATTORNEY 06L 1965 F. DRUSEIKIS ETAL INTERVAL TIMER AND DRIVE MECHANISM THEREFOR Filed Dec. 21, 1961 4 Sheets-Sheet 2 80 8.2 INVENTORfi 6, 4 FREDERICK oauss: a

C3. RALPH D. UNTERBORN BY wfiafaid THEIR ATTORNEY Oct. 26, 1965 Filed Dec. 21, 1961 F. DRUSEIKIS ETAL INTERVAL TIMER AND DRIVE MECHANISM THEREFOR 4 Sheets-$heet 3 FREDERICK DRUSEIKIS THEIR ATTORNEY RALPH D UNTERBOBN Oct. 26, 1965 F. DRUSEIKIS ETAL 3,213,695

INTERVAL TIMER AND DRIVE MECHANISM THEREFOR Filed Dec. 21, 1961 4 Sheets-Sheet 4 FREDERICK DRUSEIKIS RALPH D. UNTERBORN BY THEIR ATTORNEY United States Patent 3,213,695 INTERVAL TIMER AND DRIVE MECHANISM THEREFOR Frederick Druseikis and Ralph D. Unterborn, both of Rochester, N.Y., assignors to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Dec. 21, 1961, Ser. No. 161,209 9 Claims. '(Cl. 74-352) This invention pertains to interval timers, and particularly to an improved drive and control mechanism for interval timers.

Heretofore, appliance timers, such as used to control the various cycles of an automatic washing machine, operated on a fixed time base, and hence included a plurality of cams which were advanced in a step by step manner at periodic intervals, for instance at sixty second intervals. These cams act both as function cams, i.e., to perform the necessary switching operations, and as time cams for determining the interval when their respective switches are closed or opened. Inasmuch as appliance timers must be relatively small and inexpensive, as a practical matter it has been found that with ratchet wheels of two inches in diameter, the maximum number of steps is limited to sixty. Hence, if the timer operates on a time base of sixty seconds, it is apparent that each function performed by the cams must be a minimum of sixty seconds and can have a maximum time which is only a multiple of sixty seconds.

The present invention relates to an interval timer wherein time has been removed from the function cams and a separate time cam coordinated with the function cams is provided to obtain the necessary time pulses for the required function. By having the time cam separate from the function earns, the critical switching conditions which are present in conventional timers are eliminated, and a ratchet drive for the function cams can be designated to accomplish a greater angular movement during each step so as to make the timer more reliable. Moreover, it will be appreciated that the base time pulses can be reduced from the heretofore conventional sixty second pulses to base time pulses in the range of between fifteen and twenty seconds. In this manner the duration of the functions performed by the switching cams can be reduced to the interval of the base time pulses or increased to any desired time interval.

Accordingly, among our objects are the provision of drive mechanism for an interval timer including variable time interval advance means; the further provision of an interval timer including separate time and function cams; and the still further provision of an interval timer including a timing gear and a variable interval time cam for controlling the driving connection between the timer motor and the ratchet advance mechanism.

The aforementioned and other objects are accomplished in the present invention by embodying an interruptible driving connection between the ratchet advance mechanism and the timer motor in combination with means actuated by the time cam for controlling the driving connection between the timer motor and the ratchet advance mechanism so as to advance the function cams at variable time intervals in accordance with a predetermined program.

This is achieved by embodying a segment gear as the driving member for a pulse cam that actuates the ratchet drive, or advance mechanism, in combination with re- 'ice starting means engageable with the segment gear as controlled by the time cam. Specifically, the drive pinion of the timer motor meshes with the segment gear and an idler. The segment gear has a pair of diametrically located toothless sections such that when the motor driven pinion is aligned with a toothless section, movement is not imparted to the segment gear, and hence to the pulse cam. The idler gear, which meshes with the restart pinion is carried on a pivotally movable cam follower engaging the time cam. When the follower engages a rise on the time cam the restart pinion is disengaged from the segment gear, and in this manner the driving connection between the timer motor and the ratchet advance mechanism is interrupted.

The timer motor also has continuous driving engagement with a time gear which is coupled by a friction clutch with the time cam. The time cam has a lost motion driving connection with the ratchet wheel and the function cams which permits the time cam to be advanced relative to the ratchet wheel and the function cams when the driving connection between the restart pinion and the segment gear is interrupted. The intervals between advancements of the ratchet wheel and hence the function cams, are determined by the circumferential, or arcuate, extent of the rises and dwells on the time cam. The time gear may be driven at any selected rate, for example, at per hour so that even advancement intervals as low as fifteen to twenty seconds can be accurately controlled by the function cams when the follower engages a dwell on the time cam. On the other hand, advancement intervals of any desired time length can be obtained in accordance with the arcuate extent of the rises on the time cam. A washing machine timer embodying the drive mechanism of the present invention for carrying out a specific program, or cycle, is disclosed in copending application Serial No. 161,- 199, filed of even date herewith in the name of Frederick Druseikis et al., and assigned to the assignee of this invention.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred embodiment of the present invention is clearly shown and wherein similar numerals depict similar parts throughout the several views.

In the drawings:

FIGURE 1 is a top elevational view of an interval timer embodying the drive mechanism of this invention.

FIGURE 2 is an enlarged view taken along line 22 of FIGURE 1 with certain parts shown broken away.

FIGURE 3 is a view similar to FIGURE 2 with the drive mechanism in another position.

FIGURE 4 is a fragmentary view similar to FIGURE 3 with the drive mechanism in a third position.

FIGURE 5 is a progressive sectional view through the drive mechanism taken along line 5-5 of FIGURE 2, with certain parts shown in phantom.

FIGURE 6 is an enlarged view taken along line 6-6 of FIGURE 1.

FIGURE 7 is an enlarged fragmentary view, taken along line 7--7 of FIGURE 8.

FIGURE 8 is an enlarged fragmentary sectional view taken along line 88 of FIGURE 6.

With particular reference to FIGURE 1, the interval timer comprises front and rear plates 10 and 12 with three transversely extending plates 14, 16 and 18 disposed therebetween. The transversely extending plates 14, 16 and 18 are held in assembled relation between the front and rear plates by interfitting tongues and slots, not shown, and the front and rear plates and 12 are interconnected by a plurality of bolts with the transversely extending plates 14, 16 and 18. A pair of terminal block assemblies 22 are suitably mounted between the front and rear plates 10 and 12, the terminal block assemblies being interlocked with the transversely extending plates 14 and 16. It is to be understood that the terminal block assemblies 22 include a plurality of switches actuated by a cam barrel assembly disposed between the transversely extending plates 14 and 16. A rotatable and axially movable control shaft 24 is journalled in the front and rear plates 10 and 12, the shaft 24 being clutchable to a bevel gear 26 including a hub 28 coaxial with the shaft 24 and having driving engagement with the shaft of the cam barrel assembly for manually advancing the same.

A synchronous motor 30 is attached to the transversely extending plate 18, the synchronous motor embodying an integral reduction unit 32 and having an output pinion 34, FIGURE 2, which rotates at a constant speed of 10 rpm. The motor driven pinion 34 is engageable with a segment pulse gear 36 rotatably supported on a stud 38 carried by the plate 18. The segment gear 36 has teeth removed from its periphery leaving toothless diametrically opposed portions 40 so that when either of the toothless portions 40 is aligned with the motor driven pinion 34, the driving connection between the segment gear 36 and the pinion 34 is interrupted. Any suitable reduction may be used between pinion 34 and gear 36, as for example a five to one reduction, when the gear 34 engages the toothed portion of the gear. 36, the gear 36 will be rotated at 2 r.p.m., or one-half revolution each fifteen seconds which constitutes-the lower time interval advancement limit. A double rise pulse cam 42 is formed integral with the segment gear 36, the pulse cam 42 being engaged by a follower 44 pivotally mounted on a stud 46 supported in the plate 18 and having an extension spring 48 connected between leg 50 of the follower and an anchor lug 52 struck out from the plate 18. The drive mechanism is enclosed by the front and rear plates 10 and 12 and a pair of plates 54 and 56 which are suitably interlocked with the transverse plates 16 and 18.

The motor pinion 34 has continuous meshing engagement with an idler gear 58 journalled on a stud 60 carried by the plate 18. A cam follower 62, in the form of a lever, is pivotally mounted on the stud 60. An adjustment plate 78 is also pivotally mounted on the stud 60 and carries a stud 64 on which a restart pinion 66 is rotatably journalled. The restart pinion 66 is movable into and out of engagement with the segment gear 36 by a follower portion 68 which is resiliently maintained in engagement with a time cam 70 by a hairpin spring 72. The follower lever 62 has elongated holes 76 and 77, FIGURE 5, which receive the studs 60 and 64, respectively, and is interlocked for rotation about the stud 60 with the adjustment plate 78. The adjustment plate 78 carries a screw 80 which bears against the cam follower lever 62 for adjusting the position thereof relative to the stud 60 and the time cam 70. In addition, the plate 78 carries a second screw 82 engageable with a struck out lug 84 on the plate 18 which constitutes a step limiting counterclockwise angular movement of the cam follower under the urge of the hair pin spring 72.

The idler gear 58 meshes with a time gear pinion 86 attached to a shaft 88 journalled in plates 16 and 18. As seen in FIGURE 7, a worm 90 attached to the shaft 88 meshes with a worm gear 92 integral with a transversely extending worm shaft 94 journalled between lugs 96 and 98 struck out from the plate 16. The worm shaft 94 meshes with a time gear 100 which, as seen in FIGURE 8, is attached to a sleeve 102 journalled on the cam barrel shaft 104. A plurality of axially spaced function cams 106 are mounted on a knurled portion 108 of the cam barrel shaft 104 so as to rotate therewith. A bushing 110 4 is journalled on the sleeve 102, and the time cam 70 is rigidly attached to the bushing by staking 112. The time cam 70 has an axially extending lug 114 which extends through an elongate arcuate slot 116 in a ratchet wheel 118 which is staked at 120 to the cam barrel shaft 104. As seen particularly in FIGURE 6, the elongated arcuate slot 116 permits the time cam 70' to advance relative to the ratchet wheel 118 through an angle greater than a tooth on the ratchet wheel, and thus constitutes a lost motion connection which determines the upper time interval advancement limit. The specifically disclosed ratchet wheel 118 has thirty equally angularly spaced teeth 122 on its periphery, and thus the teeth are spaced 12 apart, but the number of teeth can be varied as desired.

The bushing 110, and hence the time cam 70, is drivingly connected to the time gear 100 through a springtype friction clutch 124 which, as shown in FIGURE 7, is keyed to the bushing at 110 and has a plurality of spring arms disposed in a face groove 126 of the time gear 100. In addition, the time gear 100, and hence thesleeve 102 and the bushing 110, are biased downwardly, as viewed in FIGURE 8, relative to the plate 16 by a leaf spring member 129 so as to maintain the snap ring 130 in engagement with the plate 16. A second snap ring 132 engages the sleeve 102 and the bushing 110 to prevent disassembly thereof.

The friction clutch between the time gear 100 and the bushing 110 which carries the time cam 70 enables the bushing 110 and the time cam 70 to be rotated by the ratchet wheel 118 when the end 116a of the slot 116 engages the tang 114 on the time cam as seen in FIG- URE 6. It is to be understood that the ratchet wheel 118 is driven in a counterclockwise direction as viewed in FIGURE 6, and the time gear 100 is also capable of driving the time cam 70 in the counterclockwise direction through the spring friction clutch as will be described hereinafter.

Referring again to FIGURE 2, the cam follower 44 carries a drive pawl 134 for advancing the ratchet wheel 118. The pawl 134 is pivotally mounted on a stud 136 and biased into engagement with the teeth 122 on the ratchet wheel by a torsion spring 138. As is apparent, during rotation of the pulse cam 42 by the gear 36, the extension spring 48 will be stressed, or energy stored therein, as the follower 44 engages the rise on the cam so as to effect counterclockwise pivotal movement of the follower about the stub shaft 46. When the follower engages the sharp fall on the pulse cam 42, the extension spring 48 will immediately effect clockwise pivotal movement of the follower 44 so as to advance the ratchet wheel 118 throughout a distance of one tooth, or in other words, 12. Angular movement of the ratchet wheel 118 will turn the cam barrel shaft 104 and the function cams 106. Likewise, if the tang 114 is in engagement with the end 116a of the slot as shown in FIGURE 6, the time cam 70 will also be advanced through an angle of 12, but if it is not, the cam 70 will be advanced a lesser amount.

With reference to FIGURES 2 and 5, clockwise angular movement of the follower 44 about the stud 46 by the spring 48 is limited by engagement of a stop tang 51 on the arm 50 with an adjustable screw 140 having threaded engagement with a struck out lug 142 in the plate 18. In FIGURE 5 is can be seen that the motor driven pinion 34 is axially elongated and that gears 36 and 58 are axially offset relative to each other. It can further be seen that the restart pinion 66 has axially spaced tooth portions, one of which engages the idler gear 58 and the other of which is engageable with the pulse gear 36. By virtue of the fact that the motor driven pinion 34 and the restart pinion 66 are angularly displaced around the periphery of the gear 36, it will be appreciated that at least one of the two pinion gears will always be capable of driving engagement with a toothed portion of the gear 36. It can also be seen in FIGURE 5 that the plate 78 is pivotally attached to the stud 60 and carries the stud 64 while the lever 62 has elongate openings 76, 77 which receive the ends of the studs 60 and 64 and allow adjustment thereof 'by the screw 80. It can also be seen that the two lobe pulse cam is integral with the segment gear 36, as hereinbefore described.

With reference to FIGURES 2, 3 and 4, the manner in which the drive mechanism operates will be described. When the motor 30 is energized, the motor driven pinion 34 rotates in a clockwise direction at a constant speed of r.p.m. The motor pinion 34 constantly drives the time gear 100through the idler 58, and the gear reduc tion including gear 86, worm 90, worm gear 92 and worm 94 at a speed of one-third revolution per hour, for example. The time cam 70 will be driven through the spring friction clutch 124 at the same speed as the time gear 100, namely one-third revolution per hour, or 2 per minute, in the clockwise direction as seen in FIG- URES 2, 3 and 7. As long as the motor driven pinion 34 is aligned with the toothless section 40 on the pulse gear 36, and the restart pinion 66 is disengaged from the pulse gear 36, as shown in FIGURE 4, the pulse gear remains stationary. The restart pinion 66 is maintained disengaged from the pulse gear 36 when the follower 68 engages a rise 144 on the time cam 70. As seen in FIG- URE 6, the rises 144 are of varying angular extent, and are spaced apart by dwells 146, likewise of varying angular extent. Under these conditions, the ratchet wheel 118 is not advanced, and accordingly the cam barrel shaft 104 and function cams 106 remain stationary.

When the time gear 100 has rotated the time plate 70 to the position of FIGURE 2, the follower .68 engages a dwell 146 on the time plate under the influence of hairpin spring 72 thereby reengaging the restart pinion 66 with the segment gear 36. Accordingly, rotation in the counterclockwise direction will be imparted to the segment gear 36 by the restart pinion 66 through the idler gear 1 58 and the motor pinion 34, thus enabling the extension spring 48 to advance the ratchet wheel 118 through the drive pawl 134 as the follower 44 engages a fall on the pulse cam 42. With a five to one reduction between motor driven pinion 34 and the segment pulse gear 36, as long as the follower 68 engages the dwell 146 on the time plate, the gear 36 and hence the cam 42 will rotate at 2 rpm, and hence the ratchet wheel will be advanced through 12 at fifteen second intervals.

During advancing movement of the ratchet wheel, the time cam 70 is driven therewith after the lost motion has been taken up between the tang 114 and the end 116a of the slot 116 in the ratchet wheel. When the follower 68 engages a subsequent rise 144, the pulse gear 36 continues to rotate until the motor driven pinion is aligned with a toothless portion 40 of the gear 36. It will be noted that the toothless portions 40 are angularly oriented relative to the pulse cam 42such that thefollower 44 engages a slight dwell 43 on each cam lobe when rotation of the gear 36 is arrested. The high point of each cam lobe imparts sufiicient counterclockwise rotation of the follower 44 to enable the drive pawl 134 to engage the next tooth on the ratchet wheel 118.

From the foregoing it is apparent that by utilizing driving mechanism in accordance with the'teachings of this invention in interval timers, the down time intervals between cycles can be reduced to an absolute minimum, and can be varied to suit the requirements of the appliance which is to be controlled. Moreover, intervals of infinitely variable time between predetermined lower and upper limits can be obtained for performing the various functions of the appliance without creating critical switching conditions since the function cams remain stationary during these intervals. Thus, the instant timer enables a greater number of functions to be performed with a fixed cam diameter. The separation of time and function from a single cam enables a timer to 'be built wherein each angular advance can be appreciably increased, for example, from 6 to 12, thus simplifying the manufacture of the switching or function cam-s by reducing the critical tolerance requirements.

While the embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

I1. Drive mechanism for a variable interval timer including, a timer motor, a time gear driven by said motor at a constant speed, a time cam driven by said time gear but capable of movement relative thereto, a ratchet wheel having a lost motion driving connection with said time cam, a pulse gear having an interruptible driving connection with said timer mot-or, a pulse cam driven by said pulsegear, ratchet advance mechanism actuated by said pulse cam, and means actuated by said time cam for controlling the interruptible driving connection between said pulse gear and said timer motor.

2. An interval timer including, a timer motor, a time cam driven by said timer motor, a plurality of function earns, a pulse gear having an interruptible driving connection with said timer motor, a pulse cam driven by said pulse gear, ratchet advance means driven by said pulse cam and operable to impart incremental movement to said function cams, and means actuated by said time cam for controlling the interruptible driving connection between said pulse gear and said timer motor so as to obtain time intervals each of which is independently variable within predetermined lower and upper limits between incremental movements of said function cams.

3. Drive mechanism for a variable interval timer including, a timer motor, a time gear driven by said timer motor, a time cam driven by said time gear but capable of movement relative thereto, ratchet advance means having an interruptible driving connection with said timer motor, said ratchet advance means being operatively connected to a ratchet wheel having function cam means operatively connected thereto, and means actuated by said time cam for controlling said interruptible driving connection to independently vary each interval between successive actuation of said ratchet advance means.

4. The drive mechanism set forth in claim 3 wherein said timer motor includes an output pinion, and wherein said ratchet advance means includes a pulse gear having diametrically opposed toothless arcuate segments such that the driving connection between said output pinion and said pulse gear is interrupted when a toothless segment is aligned therewith.

'5. The drive mechanism set forth in claim 4 wherein said output pinion has continuous meshing engagement with an idler gear, and a restart pinion having continuous meshing engagement with said idler and pivotally movable into and out of engagement with said pulse gear for establishing the driving connection between said output pinion and said pulse gear.

6. The drive mechanism set forth in claim 5 wherein said pivotally movable restart pinion is carried by a cam follower, and resilient means biasing said cam follower into engagement with said time cam.

:7. The drive mechanism set forth in claim 4 wherein said ratchet wheel, said time gear and said time cam are coaxially mounted.

8. The drive mechanism set forth in claim 7 wherein said time cam is drivingly connected to said time gear by a spring friction clutch, and wherein said time cam has a lost motion driving connection with said ratchet wheel.

:9. The drive mechanism set forth in claim 8 wherein the lost motion driving connection between said time cam and said ratchet wheel comprises an arcuate slot in one of said ratchet wheel and time cam, and a lug on the other of said ratchet wheel and time cam whereby said time cam can be advanced relative to said ratchet wheel by said time gear, and said time cam can be advanced relative to said time gear with said ratchet wheel by slippage of said spring friction clutch when the lost motion References Cited by the Examiner UNITED STATES PATENTS 1,542,400 6/25 Ter Meer 74-125.5 2,208,831 7/40 Basset 74-125 8 Reid 74-568 Barth 74-125 Ellis 74-84 X Horner 74-125 X MILTON KAUFMAN, Primary Examiner. BROUGHTON G. DURHAM, Examiner.

Claims (1)

1. 2. AN INTERVAL TIMER INCLUDING, A TIMER MOTOR, A TIME CAM DRIVEN BY SAID TIMER MOTOR, A PLURALITY OF FUNCTION CAMS, A PULSE GEAR HAVING AN INTERRUPTIBLE DRIVING CONNECTION WITH SAID TIMER MOTOR, A PULSE CAM DRIVEN BY SAID PULSE GEAR, RATCHET ADVANCE MEANS DRIVEN BY SAID PULSE CAM AND OPERABLE TO IMPART INCREMENTAL MOVEMENT TO SAID FUNCTION CAMS, AND MEANS ACTUATED BY SAID TIME CAM FOR CONTROLLING THE INTERRUPTIBLE DRIVING CONNECTION BETWEEN SAID PULSE GEAR AND SAID TIMER MOTOR SO AS TO OBTAIN TIME INTERVALS EACH OF WHICH IS INDEPENDENTLY VARIABLE WIT IN PREDETERMINED LOWER AND UPPER LIMITS BETWEEN INCREMENTAL MOVEMENTS OF SAID FUNCTION CAMS.

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