US2906330A - Timer - Google Patents

Description

3 Sheets-Sheet 1 Sept. 29, 1959 P. G. FRERE-:R ET AL TIMER Filed June 19, 1956 G N QN www l :darf

Sept. 29, 1959 P. G. FRERER ETAL 2,906,330

TIMER Filed June 19, 1956 s Smets-sheet 2 Sept. 29, 1959 P. G. FRERER ETAL 2,906,330

TMER

Filed June 19, 1956 3 Sheets-Sheet I5 NVE/Www v @ufm " G? KJ@ M United States Patent O TIMER Paul G. Frerer, Elmhurst, and James N. Yamasaki, Peru,

Ill., assignors to Controls Company of America, a corporation of Delaware Application :lune 19, 1956, Serial No. 592,454 13 Claims. (Cl. 161-1) This invention relates to a timer with a linearly movable adjusting element. The new timer is particularly useful for clothes dryers, although applicable to many other devices.

In such appliances as clothes dryers and the like, timers I `said timing means requiring minimum depth and extending for a distance parallel to the surface of the housing. A timer of this type can accommodate a straight scale and indicating means in distinction to timers having circular scales and requiring deep space inwardly of the housing wall.

While a timer embodying the invention may be used with electric or gas clothes dryers, it is particularly adapted to control the heavy currents required by electric clothes dryers. It follows, therefore, that a timer embodying the present invention will easily fulfill the less rigorous demands made upon the same by a gas-fired dryer. The timer is useful for other appliances, such as electric stoves.

The invention in general utilizes a motor-driven release means for alternately operating on a pair of opposed racks. The racks are disposed in opposed relation and are generally similar. Cooperating with the two racks is a carriage assembly having detent means. The carriage assembly is generally movable along a line parallel to the opposed racks and is preferably biased to one end of a travel range. By alternately rocking each rack clear of the cooperating detent and by providing for staggering of the detent action, the carriage assembly may be stepped along under the control of an electric clock type motor.

The racks for rocking the carriage assembly through the detent means have suitably spaced teeth so that the carriage assembly may have any desired lost motion between successive steps. The lost motion may be utilized for effecting switch or other control action. Manual means are provided for disengaging the coupling between the carriage assembly and the two racks to provide free movement of the carriage assembly along its line of travel for selecting a suitable starting position.

By virtue of this arrangement the load on the driving motor will always remain low and be restricted substantially to rotating the cam. Hence a low power clock type motor may be used. The power available for switch action or control action, however, may be large and will be stored in the carriage assembly biasing means. The amount of carriage assembly bias and length of lost motion travel of the carriage assembly will determine the lCC energy and the amount of movement available for switch or control action.

For more thorough understanding of the invention, reference will now be made to the drawings, wherein embodiments illustrative of the invention are disclosed and described, it being understood that variations may be made without departing from the scope of the invention except as defined by the appended claims.

Figure l is a top View of a timer embodying the present invention, with certain parts broken away;

Figure 2 is a sectional view along line 2-2 of Figure l;

Figure 3 is a detail of the manually controlled detent means for locking the carriage assembly to the two racks, the two racks being shown clear of the carriage;

Figure 4 is a sectional detail upon line 4-4 of Figure l;

Figure 5 is a sectional detail along line 5-5 of Figure l;

Figure 6 is a perspective detail of certain parts of the manual control;

Figure 7 is an exploded View of the means for rocking the two racks from a motor or other source of power;

Figure 8 is a detailed perspective of a modified form of the cam-actuating means for rocking the racks;

Figure 9 is a detail in the plan of a modified form of construction embodying the present invention, wherein the electric motor and cam means are disposed on the carriage; and

Figure l0 is a section along line 10-10 of Figure 9.

The timer comprises elongated housing 10 having bottom 11, ends 12 and 13 and sides 14 and 15. Cover 16 may be provided. The housing may be made of any suitable material such as metal or plastic and may be constructed and assembled in any desired manner. For convenience, bottom 11 of the housing will be assumed to be of insulating material, such as Bakelite. This makes it possible to mount suitable electric contact strips thereon, as will be more fully explained later. As is clearly shown, housing 10 is elongated and may conveniently have a rectangular shape.

Supported near one end of bottom 11 of the housing is electric motor assembly, generally indicated by 20. This assembly may include an electric motor of the type used in electric clocks and may also include suitable gearing for providing a desired slow output speed. The motor assembly, generally indicated by 20, may be attached to bottom 11 in any desired fashion, as by screws 21, and has output shaft 23.

Shaft 23 passes through a suitable clearance opening in bottom 11 of the housing and extends into the interior of housing 10. Shaft 23 carries cam 25 at the end thereof, the cam lying in a generally horizontal plane, as seen, for example, in Figure 7. Cam 25 has drop 26 disposed between rise V27 and the remainder of the cam, generally indicated by 28. The direction of rotation of cam 25 is illustrated by the arrow in Figure 7.

Bottom 11 of the housing has the inside adjacent t0 shaft 23 recessed or cut away to provide a lateral slot for accommodating superposed slide members 31 and 32. These slide members may conveniently be of metal and are provided with centrally disposed slots 33 and 34 for clearing shaft 23. Each of the slide members has a cam follower finger cut out therefrom and bent upwardly out of the plane of the metal. Thus slide member 31 has finger 3S passing through a suitable slot in slide 32, while slide 32 has finger 36. The two lingers are on opposite sides of shaft 23 and are adapted to function as cam followers.

The two slide members are biased so that the cam follower fngers are pressed against cam 25. The arrangement is such that as cam 25 rotates, each of the cam follower iingers is alternately forced outwardly away from shaft 23 by cam rise 27. After cam drop 26 passes a iinger, the spring Ybias on a slide member results in sudden yinward movement of the slide member. Cam drop 26 need not be sharp, since the inward movement of the slide member is useful only to prepare the slide for its next motion. j

It is understood that cam 25 is so shaped that the slide members are forced outwardly at appropriate cam positions. Where one or more cycles per cam revolution are provided, a single cam W-ill suice. In such case the angular extent of the cam rise may be as much as 180 degrees. For slower movement, each slide member may have an individual cam which could have a maximum angular rise something less than 360 degrees, the remainder being required by the drop.

' Slide member 32, which is on top of slide member 31, is provided with slot 38 through which iinger 35 from slide member 31 may project. Slot 38 is so dimensioned as to permit relative movement of the two slide members. Slide member 31 has sloping end portion 4t), while slide mern ber 32 has sloping end portion 41. These two end portions are disposed opposite each other and are adjacent to the inside faces of sides 14 and 15 of the housing.

Longitudinally disposed within housing are opposed racks 43 and 44,v respectively. The two racks have mounting ears at their respective ends and are supported for rocking movement on elongated pins 46 and 47. Pins 46 and 47 extend through suitable apertures in end walls 12 and 13 of the housing and these pins may be locked in position by any suitable means, such as, for example, by headed portions at one end of each pin and spring lock washers at the other end. Any means for securing the pins in position may be utilized.

' Rack 43 has the general shape of an angle iron with y body portion 48 and toothed portion 49 at right angles thereto. Similarly, rack 44 has body portion 50 and toothed portion 51. As is clearly evident in the various iigures, toothed portions 49 and 51 of the two racks extend toward each other. They two racks are preferably similar in construction and have corresponding rack teeth. Racks 43 and 44 may be mounted in such manner that the tips of the teeth of the two racks are not in line with each other transversely across the housing, but instead are staggered with relation to transverse lines.

End portions 40 and 41 of the transverse sliding members are dimensioned so that they engage, respectively, the body portions of the racks, as illustrated in Figure 5. Coil springs 53 and 54 are disposed in suitable recesses in the housing sides and rest against the outside faces of the body portions of the two racks for biasing these racks toward each other. It will be clear that these springs press the racks against the end portions of sliding members 31 and 32 and function to press fingers 35 and 36 to engage the surface of cam 25. Y I

As shaft 23 is rotated by clock motor 20, cam 25 will be turned. As a finger on a slide member rides on rising portion 27 of the cam, the corresponding slide member Will be moved to force its cooperating rack r`utwardlv against its spring bias. Thus, each rack will be alternately rocked away from the opposing rack with cam rotation.

Sides 14 and 15 of the housing have the top portions cut away at 55 and 56 to provide longitudinal guideways. As indicated in Figure 5, these guideways are disposed above rack tooth tooth portions 49 and 51,. This, however, is not essential, as will be apparent later. Operating in guideways 55 and 56 is a carriage, generally indicated by 57. This carriage may consist of a generally rectangular block of material either of metal or non-metal. Carriage 57 is long enough along the length of housing 1@ so that the carriage will slide smoothly and be substantially free of turning. j i i A Carriage plate 57 is sliclable substantially. along theY entire length ef the housing and biasedV toward one end of the housing by cord 59 and spring reel 60. The spring reel may be secured on the carriage if desired, in which case cord 59 would be anchored t0 the hOUSng, As iltlllnS- 4 trated, however, cord 59 is tied to carriage block 57 as by -pin 61. Spring -reel 6i) is carried by bracket 63 supported from end 12 of the housing. As illustrated in Figure 1, spring reel 60 tends to pull the carriage toward it.

Carriage plate 57 has rigidly secured to the bottom thereof detent plate 65 extending transversely of the housing. Detent plate 65 has Support arms 66 and 67 suitably apertured for attaching to carriage plate 57. Detent plate 65 is short enough to lie within body portions 48 and 5.0 of the two racks irrespective of the rack positions. vDetent plate 65 carries detent tee- th 69 and 70 for cooperation, respectively, with the teeth of the two racks. Detent teeth 69 or 70 may engage the opposing rack teeth when the racks are nearest to each other. Upon rocking of either or both racks outwardly away from each other, the teeth of lthe particular rack or racks which have been rocked will clear detent teeth `69 or 70, or both, as the case may be.

Detent teeth 69 and 70 are here illustrated as being in line transversely across the housing. Thus, one detent tooth will be about halfway between two adjacent rack teeth when the other detent tooth will engage a Yrack tooth. This is because the two racks are staggered as previously pointed out. However, `the two racks may be aligned so that their teeth are opposite each other and detent teeth 69 and 70 may be positioned out of line to result in alternate engagement described above. The ral; and detent teeth are so shaped that the carriage cannot be moved in either direction except when both detent teeth are clear of the racks.

It is desirable to provide means for manually moving carriage plate 57 freely along the housing. To this end, detent plate 65 supports stub shaft 72 extending upwardly and carrying knob 73 at the end thereof. Cover 1 6 of the housing is slotted at 74 to clear stub shaft 72 irrespective of the carriage position. Stub shaft 72 carries a member here illustrated as disc 76 upon which are pivotally disposed rods 77 and 78. Rods 77 and 78 extend generally away from each other toward the racks and their free ends are adapted to engage body portions 48 and 50 of the racks. Rods 77 and 78 are slotted near their ends `f or cooperation with guide pins 79 and 79a, respectively, carried by detent plate 65.

By rotation of stub shaft 7,2, rods 77 and 78 may be withdrawn or retracted to clear the racks o r may be extended to rock the two racks outwardly away from each other. In this latter position, the racks will clear detent teeth 69 and 7 t) and permit the carriage plate to be manually moved to any desired position. This is illustrated in Figure 3. In the position illustrated in Figure l, however, the manual control is in a contracted position with rods 77 and 7S clearing the racks.

Assuming that the spring reel exerts a suiiciently strong pull on the carriage, as cam 25 is rotated by the motor, the racks will be alternately rocked. This will permit carriage plate 57 to respond to its spring bias and move half a tooth in successive steps. By having sufficient tension at the spring reel and providing for suflicient movement of the carriage for each step, a powerful actuating force is available for operation of electric or other control means.

As illustrated here, carriage plate 57 is adapted to control electric circuits. To accomplish this, the carriage plate has` electric contact member provided with a number of spring fingers S1 extending downwardly toward bottom'plate 11 of the housing. Bottom plate 11 of the housing may carry a number of contact strips 32 extending lengthwise of the housing, these contact strips being-suitabiy disposed and positioned so that the movable contact fingers may cooperate therewith for eiecting circuit QQntrQI- By controlling positions 0f the` ends. 0f the various come@ strips algue the Carriage travel range. circuits may be opened orclos'ed as the carriage plate moves along the housing at predetermined points of carriage v travel. Since the motor is effectively a clock, the entire device becomes a timer. It is possible to provide circuit connections for opening the clock motor winding circuit when the carriage has reached the end of its travel.

It will be apparent that each rack may be bodily moved transversely instead of being rocked. The racks have three definite positions with reference to the detent teeth. In one extreme position, the racks have their rows of teeth closest to each other to cooperate with both detent teeth. In the other extreme position, the racks have their rows of teeth with maximum separation and clear both detent teeth. In the intermediate position, one or the other rack clears a detent tooth and the remaining rack will cooperate with the corresponding detent tooth.

Instead of having one detent tooth for a rack, a number of such teeth may be provided.

The teeth may be non-uniform in regard to pitch and depth and the teeth of one rack need not be symmetrical with the teeth of the other rack. This make for greater control flexibility.

It is clear that in the form of the invention so far described, and particularly illustrated in Figure 7, at least one operating cycle per cam revolution is involved. Where one cam is used, the maximum angular extent of the cam rise may be as much as 180. It may be desirable in some instances to use a slower moving cam, in which case it is possible to separate the cam functions. Thus, referring to Figure 8, each rack is provided with its own individual operating cam. As illustrated in Figure 8, shaft 23a has cams 25a and 25b, respectively, secured thereon. These two cams are in spaced parallel relation and are generally similar and are angularly offset by substantially 180. Thus, cam 25a has drop 26a and rise 27a. Cam 25h is similarly provided with drop 26b and rise Z7b.

In the modification illustrated in Figure 8, it should be noted that slide members 31a and 32a have cam follower fingers 35a and 36a adjacent the flat ends of these slide members rather than adjacent the upturned ends 40a and 41a as in Figure 7. This, of course, results in a reversal of the cam operation of Figure 7. Thus in Figure 7, the cam rise operates a finger to push a slide member in a direction to rock the corresponding rack outwardly. In short, the cam rise results in outward rocking of a rack. In Figure 8, however, the cam drop is effective for rocking the rack outwardly. In this form it'is necessary to provide a bias force on the sliding members for proper operation. To this end spring 37 has its two ends anchored to fingers 35a and 36a, the spring tending to pull these fingers together. Portion 37a of the spring may be straightened out to extend around shaft 23a. The tension in spring 37 should be greater than the force of spring 53 and 54 for biasing the racks toward each other. It is, of course, possible to provide a positive connection between the bent ends of the sliding members both in Figures 7 and 8 and the corresponding racks to make it unnecessary for the spring bias of the racks to press against the sliding members.

The arrangement illustrated in Figure 8 thus results in the cam drop being effective to move a rack outwardly for clearing the detent teeth. The cam drop in such case may be made quite steep and, by proper application of spring force, the movement of the rack may be speeded up to the point where a sharp release of the carriage is provided. In the modification illustrated in Figure 7, the carriage release occurs on a cam rise, and since this is gradual, it is clear that the entire detaining force of one or more teeth must be provided by a decreasing area of tooth as the rack is moved. Theoretically, in the form illustrated in Figure 7, just before the carriage release, the entire carriage-detaining force, which is due to the tension means, will be concentrated upon a microscopic area of one or more rack teeth depending, of course, upon how many detent teeth are used with each rack. In the form illustrated in Figure 8, however, a rack may be moved outwardly at comparatively high speed with the result that the rack need not creep but can move quickly and without imposing great strain upon the rack teeth tips. Thus, in the form illustrated in Figure 8, the cam drops are preferably steep and the shape does have a function. As has been previously pointed out, the drop in the cam for Figure 7 performs no useful function, since the rack has already been moved to an outer position for tripping the carriage and will now be permitted to move inwardly to assume a new operating position.

In the modification illustrated in Figure 8, it is the cam rise which, generally speaking, has no substantial functional purpose other than to permit the corresponding rack to assume an inward position.

It is, of course, possible to eliminate one of the cams in Figure 8 and have both slide members operated by one cam as in Figure 7. The advantages of a sharp rack release inherent in the construction illustrated in Figure 8 will still be retained. y

The modifications of the invention so far described involve a stationary electric timing motor, provided with suitable means for rocking the racks alternately. It is possible to mount the rocking mechanism, including the motor upon the carriage. Thus, referring to Figures 9 and l0, carriage 57a may have the same general construction as carriage 57 in the previously described forms of the invention. Carriage 57a, in addition, supports electric motor 20a. Electric motor 20a preferably includes as part of the entire assembly suitable reduction gearing and has its power output shaft 123 coupled to a cam rocking means such as illustrated in Figure 7. The cam rocking means and the sliding members are supported on carriage 57a, the sliding members having ends 140 and 141 which are adapted to slidingly engage the inside faces of the bodies of the two racks. Thus, as the carriage moves along its range of travel, the racks may be alternately rocked to permit the carriage to advance. Power for operating the motor may be picked up by wipers, traveling along conductors supported in the base, or may be provided by fiexible wires connecting the traveling carriage to stationary terminals on the base.

It is clear that the cam-rocking means illustrated in Figure 8 may also be used in the modification illustrated in Figures 9 and l0.

In all forms of the invention, the teeth of one particular rack need not necessarily be uniform, nor is it necessary that the two racks match. The only requirement is that every face or surface of a rack tooth, which functions to detain the carriage, should not be directly opposite the corresponding detent face of a tooth on the other rack, assuming that the carriage detent teeth are transversely aligned. A If the detent teeth are not aligned, the only requirement is that the opposing detent teeth do not simultaneously engage the teeth of the two racks.

What is claimed is:

1. A timer comprising a base, a pair of racks, said racks having teeth and being mounted on said base so that the racks are opposite each other, means for securing said racks so that they may be moved to shorten or lengthen the distance between the row of teeth on one rack and the row of teeth on the other rack, said racks having positions of minimum, intermediate and maximum separations, a carriage slidable on said base in a direction parallel to the racks, a detent tooth on each side of said carriage for cooperation with a rack, one said detent tooth for cooperation with one rack and the other said detent tooth for cooperation with the other rack, said detent teeth being spaced so that when said racks are in the intermediate position, one detent tooth will be clear of the teeth of its corresponding rack while the other detent tooth will still be able to cooperate with the teeth of its corresponding rack, said detent teeth being clear of both racks in one said position of maximum separation and cooperating with both racks in said position of minimum separation, said rack teeth and detent teeth being arranged so that a point of tooth engagement between a -,detent tooth and a cooperating rack tooth is staggered -along the length of ,said rack with respect to the point of tooth engagement of the remaining detent tooth andeooperating rack tooth, means for biasing `said carriage toward .011e end Of its travel range, motor means for alternately moving said racks between said position of miniseparation and said intermediate rack position .SO that said carriage may be moved in response to its bias, manual means for moving said racks to said position of maximum separation to permit said carriage to be moved manually along its rangeV of travel, and means operated by the movement of said carriage for etecting a control action.

2, The timer according to claim l, wherein said Vmeans for eifecting a control action includes electric contacts for switching circuits with movement of said carriage.

3. A timer comprising a base, a pair of racks, said racks having teeth and being mounted so that said racks are parallel and opposite to each other, means for mounting said racks for rocking movement so that the separation between the two rows of rack teeth may be varied between minimum and maximum with said racks having an intermediate separation position, a carriage disposed between Said racks and slidable parallel thereto, a detent 190th on each vSide of the carriage for cooperation with a `rack, one detent tooth for cooperation with one rack and the other detent tooth for cooperation with the other ael, Said detent teeth being spaced so that both detent teeth can cooperate with the teeth of both racks in the minimum separation position, the maximum separation permitting said detent teeth to clear both racks while the intermediate separation position permits complete clearance between one rack and detent or the other rack and dent depending upon which rack is moved, the rack and detent teeth of one cooperating pair being positioned with respectV to the other cooperating pair so that in the minimum separation position only one detent tooth is in actual engagement with a rack tooth, the other detent tooth being between adjacent rack teeth, means for biasing the carriage to one end of its travel range and means including a motor for alternately moving one rack and then the other between the minimum and intermediate positions and back again so that said carriage may step along the racks, manual means for moving both racks simultaneously to positions of maximum separation to permit said carriage to be moved along its range of travel, and means operated by the movement of said carriage for effecting a control action.

4. The timer according to claim 3, wherein means are provided for biasing said two racks toward positions of minimum separation.

5. The timer according to claim 3, wherein said means for alternately moving one rack and the other comprise sliding members having portions for engaging their respective racks, each sliding member having a ringer, a cam for operating said iingers to move such sliding members, and means for driving said cam from said motor.

6. The timer according to claim 3, wherein each rack has the general shape of an angle iron with the teeth generally pointed toward each other, the means for alternately moving the two racks including slidable members disposed transversely of the racks and having portions engaging the bodies of the two racks, a cam, said cam cooperating with said sliding members to move the same transversely of the racks for rocking the racks, and means for driving said cam from said motor.

7. A timer comprising a base, a pair of racks, said racks having teeth and being mounted so that said racks are parallelY and opposite to each other with the teeth extending toward each other, means for mounting said racks upon said base for rocking movement so that the separation between the .two rows of rack teeth may be varied .between minimum .and maximum with said racks having lan intermediate separation position, a carriage disposed between said racks and slidable parallel thereto, ,at least one detent tooth on each side of the carriage for cooperation with a rack, one detent tooth for cooperation with one rack and the other detent tooth for cooperation with the other rack, said detent teeth being spaced so that both detent teeth can Vcooperate with the teeth of both racks in the minimum separation position, the maximum separation position permitting both of said detent teeth to clear the two racks, the intermediate separation position permitting one rack or the other to clear the corresponding detent tooth, the rack and detent teeth of one Cooperating pair being positioned with respect to the other cooperating pair so that in the minimum separation position, only one detent tooth is actually engaged by a rack tooth, the other detent tooth being between adjacent rack teeth, means for biasing the carriage to one end of its travel range, means including a motor for moving one rack and then the other rack between the minimum and intermediate positions and back again so that said carriage may step along the racks, said means including fa sliding member for each rack, said tooth sliding members being disposed on said base for movement transversely of said racks, means for biasing said racks toward one of said two positions between which said racks are moved by said motor, cam means connecting said sliding members and said motor for moving said racks to the other of the two positions between which said racks are alternately moved, manual means for moving both racks simultaneously to positions of maximum separation to permit said carriage to be moved along its range of travel, and means operated by the movement of said carriage for etecting a control action. Y

8. The timer according to claim 7, wherein electric contacts are mounted on said base and wherein means are carried by said carriage for cooperating with said electric contacts for controlling circuits in accordance with the movement of said carriage.

9. The timer according to claim 8, wherein said electric contacts on said base consist of elongated metal strips parallel to said racks and wherein the said carriagesupported means include contact fingers for cooperating with the base-supported contacts.

10. The timer according to claim 8, wherein the means for moving said racks include one cam and spring-pressed cam followers for coupling said cam to both racks.

11. The timer according to claim 8, wherein the means for moving said racks include two cams, said cams being coaxial, a cam follower for each cam for coupling the cam to a rack, and spring means for urging said followers against said cams, said spring means being interconnected.

12. The timer according to claim 8, wherein said driving motor and cam means are mounted on said base.

13. The timer according to claim 8, wherein said driving motor and cam means are mounted on said carriage.

References Cited in the le of this patent UNITED STATES PATENTS 810,370 Follett Ian. 16, 1906 1,371,781 Gains Mar. l5, 192,1 2,060,299 Gensburg Nov. l0, 1936 2,182,894 Hammell Dec. 12, 1939 2,475,730 Wandrey July 12, 1949 2,641,661 Puerner et al. June 9, 1953

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