US2821249A - Time switch - Google Patents

Description

E. S. SMITH TIME SWITCH Jan. 28, 1958 5 Sheets-Sheet 1 Filed Jan. 11, 1955 lb Z .Mn. l4

INVENTOK/ e 5 SMITH BY ATTo es Jan. 28, 1958' E. 5. SMITH 2,821,249

TIME SWITCH Filed Jan. 11, 1955 3 Sheets-Sheet 2 INVCNTOR/ E 5. SMITH ATTOIZNEY5 E. 5. SMITH TIME-SWITCH Jan 28, 1958 v Filed Jan. 11, 1955 3 Sheets-Sheet 3 INVENTOR,

E 5 SMITH ATTowevs v United States Patent TIME SWITCH Elmore Stanley Smith, Weston, Ontario, Canada, assignor to Molfats Limited, Weston, Ontario, Canada, a corporation Application January 11, 1955, Serial No. 481,232

Claims. (Cl. 161---1) The present invention relates particularly to time controlled switches, time controlled valves and the like. Although not limited thereto, the invention is primarily for use as a control switch for the surface elements of domestic electric ranges and therefore it is described herein in combination with such switches.

The principal object of the invention is to provide a time controlled switch or valve which at one setting may be adjusted so that initially it is at one condition and so that after a predetermined time has elapsed it automatically shifts to another condition. For example, a time switch having these characteristics may be set initially so that the surface element is at high and after a predetermined time interval it automatically shifts to the off position and remains at that position. As another example, the switch may be set initially so that the surface element is at medium and after a predetermined amount of time has elapsed it will automatically shift to high and will remain in that position until the switch is manually reset to another position.

A further object of the invention is to provide a time switch or valve which is so constructed that it may be operated as a conventional manual switch, Without necessarily using its automatic position shifting feature.

Another object of the invention is to provide an improved time switch construction which is simple and convenient to operate and is relatively inexpensive to manufacture.

The invention is more particularly described with reference to the accompanying drawings, in which like reference characters designate corresponding parts in the several views and in which:

Fig. l is a perspective view of a time switch constructed in accordance with the invention and shown installed on a fragment of a control panel of an electric range;

Fig. 2 is an exploded perspective view of the timeswitch of Fig. l, viewed from above;

Fig. 3 is a cross-sectional view of the said time switch, taken through the line 33 of Fig. 5, with some portions broken away for greater clarity, the timer actuated pawl being shown in disengaged position;

Fig. 4 is a front elevation of the said time switch, with some portions broken away, the timer actuated pawl being shown in engaged position;

Fig. 5 is a partly broken away vertical cross-sectional view taken through the line 55 of Fig. 4, with the switch dial shown in normal or engaged" position; and

Fig. 6 is a view similar to Fig. 5 with the parts of the device in the position which they assume when the switch dial is in disengaged position.

Obviously the invention may be adapted for use with many different types of multi-position rotary shaft control apparatus such as valves and electric switches. The switch 10 which is shown in the drawings is a typical eight-position rotary switch of the kind used on many electric ranges operated on a 115-230 volt electrical power supply. The eight switch settings include an o 2,821,249 Patented Jan. 28, 1958 position and seven other positions whereby the resistance wires of the surface element to which the switch is con nected may be tapped to the supply lines in various manners so as to heat the element to varying degrees, in a manner well known in the art.

The switch 10 is firmly secured to strap 11 of the support 12 by self-tapping screws 13. The strap 11 which forms a constituent part of the support 12 consists of a channel member having a web 11a and upset flanges 11b which are secured to the body of the support 12 by suitable screws, the structure providing a space between the web 11a and the major surface of the body of the support 12.

Fast on the shaft 14 of the switch is a dished disc 15 having dual flanges 16 and 17, the disc being located in the aforesaid space. Teeth are formed in the flange 16 to provide the ratchet of a detent mechanism. On the face of the flange 17 are indicia 18 adapted to register in an opening 19 of the support 12 to indicate conveniently the position to which the switch has been set. One end of a pawl 20 of the detent mechanism is mounted on the support 12 for pivotal movement while its free end is engageable with the ratchet to hold the switch shaft against rotation at any one of its several positions, each tooth corresponding to a position.

Mounted for rotation in an opening 21 of the support 12 is a cylindrical motor unit including a housing 22 having a peripheral flange 22a which engages with the peripheral edge of the opening 21. Rotatably mounted in the housing is an arbor or stub shaft 23 which is con stantly urged to a fixed angular position relative to the housing by a spring motor generally indicated at 24. The spring motor may be of any suitable construction, provided that it is windable by rotation of the housing relative to the stub shaft in one direction so that when the motor is wound the stub shaft is urged to rotate relative to the housing in the opposite direction and to return to a fixed angular position relative to the housing.

As illustrated, the spring motor comprises a spiral spring 25 connected at its outer end to a stationary anchor stud 26 of the housing 22 and at its inner end to a sleeve (not shown) fast to a driving gear 27 coaxially mounted relative to the stub shaft 23. The driving gear 27 is frictionally coupled to the stub shaft 23 by a friction plate 28 firmly secured to the stub shaft and which frictionally engages the face of the driving gear. The driving gear 27 meshes through a pinion 29 with a gear train consisting of gear 30 mounted on the same arbor as pinion 29, idler pinion 31 which meshes with gear 30, idler gear 32 mounted on the same arbor as idler pinion 31., and fly wheel 33 which meshes with idler gear 32 through a fly wheel pinion 34. The train of gears and the fly wheel 33 are provided solely to apply a load to the spring motor so that the stub shaft is rotatable relative to the housing at a moderate speed; in the embodiment illustrated the speed of rotation is approximately 1 revolution per second.

Keyed to the stub shaft 23 is an arm 35 adapted to abut against a stop 36 on the housing, thereby assuring that the spring motor invariably causes the stub shaft and housing to stop at a fixed position relative to each other when the motor is unwound. It will be appreciated that when the spring motor unwinds and the arm 35 strikes the stop 36, the motor parts would be subjected to an appreciable shock were the driving gear 27 coupled directly to the stub shaft 23; however, shock is minimized by the friction disc 28 which frictionally couples the driving gear 27 to the stub shaft 23.

The stub shaft 23 is provided at its free end with a key 37 which registers with a keyway 38 in the free end of the switch shaft 14. Thus, the stub shaft is coupled to the switch shaft in torque transmitting relationship, but provision is made "for a small amount of axial movement of these two shafts relative to each other.

--A bowedv spring =39, havi'ng-a central opening in which is embraced the;stub--shaft 23,;extends diametrically across thehousing -22 and has free ends :which bear on the peripheryof the housing. The central-portion of the bowed spring is adapted to engage and bear against the free end of the switch shaft -14, and the spring thus provides biasing means which urges the housing in one axial direction so that its peripheral flange 22a bears against the major surface of the support 12. Adjacent the periphery of the opening 21 in the support are provided recesses or stops 40 with which abutments 41 of the housing 22 are adapted toengage. The stops 40 and the abutments 41 are positioned at such relative angular locations that when the stub shaft 23 has been rotated to its fixed angular position relative to the housing 22 by the unwound motor the switch shaft 14 keyed to the stub shaft is rotated to one of its settings.

Encasing and gripping the housing is a dial 42 on which are indicia 43. A resilient catch 44 in the housing 22 registers with a recess which is provided in the dial so that the dial and housing are necessarily angularly aligned in a predetermined manner. The indicia 43 are so positioned on the dial that when the housing 22 is at the fixed position relative to the shaft to which it is urged by the spring motor 24 the said indicia are in registration with the indicia 18 on the disc flange 17.

To rotate the housing 22, the user pushes axially inwardly from its normal position as shown in Fig. the dial in which is gripped the housing, that is, in the direction opposite to that to which it is urged by the biasing means 39, thus causing disengagement of the abutments 41 from thestops 40, as shown in Fig. 6, which enables him to turn the dial and housing like an ordinary switch knob. The spring motor 24 is so constructed that the force required to wind it is appreciably greater than that required to rotate, the switch shaft 14 so that when the said shaft is not held against rotation by the pawl of the detent mechanism it is rotatable to selected positions or settings by manual rotation of the dial gripping the housing. On the other hand, if the shaft is held against rotation by the pawl, of the detent mechanism and if the user rotates the dial and housing he will thereby Wind the spring motor and it will be held in wound condition by the engagement of the abutments 41 with the stops as soon as the operator releases the dial. If the pawl 20 of the detent mechanism subsequently is disengaged from the ratchet teeth, thus freeing the switch shaft 14, the spring motor will unwind and rotate the switch shaft to an angular position or setting as predetermined by the angular position to which the user had previously rotated the housing and dial.

' Firmly mounted on the support 12 is an interval timer 45 of known construction having a shaft 46 which extends through an opening 47 in the support and on the free end of which is mounted a dial 48 calibrated preferably from 0 to 60 minutes. The timer preferable used is of the kind which is settable on winding to require a predetermined lapse of time to run down and which when run down rings a bell to indicate that the predetermined time period has elapsed. Although the interval timer has been fully illustrated in the drawings its construction, which is well known, need not be described. The timer has an element 49 which shifts from a first position (as in Fig. 3) to a second position (as in Fig. 4) when the timer is set for a time measuring operation and which returns to said first position when the time measuring operation is completed. Such an element is an essential part of all interval timers, by their very nature. In the timer illustrated, the element 49 consists of a resilient spring which is urged in a counter-clockwise direction when the timer is fully unwound and which is swung in a clock wise "direction whenever the'timer is set fora time measuring operation and thus wound at least to a slight extent. A link 50 has one end connected to the swinging end of the pawl 20 and its other end is engaged with the timer element 49. When the timer is Wound and set for a time measuring operation, thereby swinging the element 49 clockwise tothe second position, the pawl 20 will engage the ratchet teeth andhold the shaft 14 against rotation; when the element 49jswings counter-clockwise and returns to the first position after the, timer has completed "atime measuring-operation, the-pawl will disengage the ratchet teeth thu's freeing the shaft for rotation. To exemplify the operation of the device, let it be assumed thatthe user wishes. toqset the switch 'sothat forthwith it wil1,be at No. 3 position for medium heat and so that 15 minutes hence it will shift to the off" or zero position. With the interval timer in unwound condition so that the pawl of the detent mechanism is not in engagement with. a ratchet -toothion 'the switch shaft, the, user rot'atesthe -dial '421gripping the housing 2210 set. the.'switch'at-1No.;.--3 :position, 'aswindicated. by :the numeral 3 iappearin'g through-Ame opening .19 (see Fig. 4). The usenithen t'urns the dia'lt48 of the intervaltti'mer 45 to a position such thatfithe numeral 15 registers-with an indicium 51 fifteen .rninutesawill thenberequired for the interval timer to unwinditself. Due to the-fact that the interval timer haspbeen set. in operation its element 49 through link =50 causes the pawl-lflcof :the .detent mechanism toiengage avratc'het tooth, thus holding the switch-shaft at No. 3 position zto which it had previously been setby the user. The-user thenipushes axially inwardly the "dial 42gtogether Withrthe motor housing 22 encased by the-dial .to cause disengagement --of the abut ments -4l.from the stops 40,?11'1d'h6 rotates the dialand housing until ythe numeral 0 on;the dial is, l0cated -adja'- cent the aperture 19;, the spring motor- 24 then is in woundcondition, and the stops ;and abutments will be in engagement when the auserereleases thehdial. At the expiry of 'the-15- minute, period-the switch shaft Will be released by the pawl-20,0f thetdetent mechanism and the wound spring motor will then; unwindand causethe switch shaft to-turn to theio-or,?off?;position, Y

It will be appreciatedw-that With the device described the switch initially ma-y be set-at any desiredposition and so that it shifts after-.atime interval as 'predeten mined by the setting of the timer to any other selected position, and notonly to. the off position -as;described in the example above. Of-course, if theuser wishes to operate the switch in the conventional manner he may do so merely by not setting the timer'so that the switch shaftis notheld against rotation bythedetent mechanism but may-be rotated freely -;by-rotation of the-.-dial-42.- Y

The embodiments ofvthe invention herewith shown and described-rare to be taken as preferred =.examples ;'of the same, and various changes -in.the. shape, sizeand arrangement 0f ,the parts :may be resorted to .without departing fromthe scope of the subjoined claims.

What I claim as.my -invention;is: 1 I

1. A device for t-manually rotating the rotary shaft of a control: apparatus =10 anyiof a plurality of selected positions -,and conditionable to automatically rotate :said shaft to any other of the said selected. positions {after a. predetermined lapse of '-time, comprising a. support -fixed rela tive to the control apparatus, a releasabledetent mechanism for holding-the ,shaft against rotation, a motor unit mounted for rotation relative to the support and including an arbor coupled to.the shaft in torque transmitting relationship, a housing manually rotatable relative'to the arbor, and a spring motor interposed between the arbor and the housing, thepspring motor being windable by manual rotation of the housingrelative tothearbor when thesha'ft is held againstrotation by thedetent-mechanism, the s ring motorwhenwound constantlyurging thea'rbor and the housing to a predetermined angular position 'relativejto'each other, theforce required to wind the spring motorbeing "appreciably greater than that re quired to rotate the shaft so that when the shaft is not held against rotation by the detent mechanism it is rotatable to any of the said plurality of selected positions by the manual rotation of the housing, manually releasable means to lock the housing against rotation relative to the support when the rotor has been rotated relative to the arbor to wind the spring motor, the wound spring motor unwinding and rotating the arbor to the said predetermined angular position relative to the housing when the shaft is freed for rotation by the released detent mechanism and consequently rotating the shaft to a corresponding position, a timer having an element which shifts from a first position to a second position when the timer is set for time measuring operation and which returns to said first position when the time measuring operation is completed, means linking the timer element and the detent mechanism to cause the detent mechanism to hold the shaft against rotation when the element is at the second position and to cause the detent mechanism to release the shaft for rotation when the element returns to the first position so that when a time measuring operation is completed by the timer the previously wound spring motor rotates the shaft from the angular position which it had prior to the winding of the spring motor by rotation of the housing to an angular position corresponding to the angular position at which the housing was locked by the manually releasable means after winding of the spring motor.

2. A device for manually rotating the rotary shaft of a control apparatus to any of a plurality of selected positions and conditionable to automatically rotate the said shaft to any other of the said selected positions after a predetermined lapse of time, comprising a support fixed relative to the control apparatus, a releasable detent mechanism for holding the shaft against rotation, a motor unit mounted for rotation relative to the support and including an arbor coupled to the shaft in torque transmitting relationship, a housing manually rotatable relative to the arbor, and a spring motor interposed between the arbor and the housing, the spring motor being windable by manual rotation of the housing relative to the arbor when the shaft is held against rotation by the detent mechanism, the spring motor when wound urging the arbor and housing to a predetermined angular position relative to each other, the force required to wind the spring motor being appreciably greater than that required to rotate the shaft so that when the shaft is not held against rotation by the detent mechanism it is rotatable to any of the said plurality of selected positions by the manual rotation of the housing, manually releasable means to lock the housing in any of a plurality of selected angular positions relative to the support when the housing has been rotated relative to the arbor to wind the spring motor, the said selected angular positions of the housing coinciding with the angular position to which the arbor is urged by the spring motor, the wound spring motor unwinding and rotating the arbor and the shaft fast thereto to the selected angular position as predetermined by the angular position of the housing when the shaft is freed for rotation by the released detent mechanism, a timer having an element which shifts from a first position to a second position when the timer is set for time measuring operation and which returns to said first position when the time measuring operation is completed, means linking the timer element and the detent mechanism to cause the detent mechanism to hold the shaft against rotation when the element is at the second position and to cause the detent mechanism to release the shaft for rotation when the element returns to the first position so that when a time measuring operation is completed by the timer the previously wound spring motor rotates the arbor and the shaft fast thereto from the angular position which they had prior to the winding of the spring motor by the rotation of the housing to the selected angular position at which the housing was locked by the manually releasable means after winding of the spring motor. I

3. A device for manually rotating the rotary shaft 0 a control apparatus to any of a plurality of selected positions and conditionable to automatically rotate the said shaft to any other of the said selected positions after a predetermined lapse of time, comprising a support fixed relative to the control apparatus, a releasable detent mechanism for holding the shaft against rotation, a motor unit mounted for rotation relative to the support and including an arbor connected to the shaft in torque transmitting relationship but axially slidable with respect thereto, a housing manually rotatable relative to the arbor, and a spring motor interposed between the arbor and the housing, the spring motor being windable by manual rotation of the housing relative to the arbor when the shaft is held against rotation by the detent mechanism, the spring motor when wound urging the arbor and the housing to a predetermined angular position relative to each other, the force required to wind the spring motor being appreciably greater than that required to rotate the shaft so that when the shaft is not held against rotation by the detent mechanism it is rotatable to any of the said plurality of selected positions by the manual rotation of the housing, interengaging means on the housing and the support to lock the housing in any of a plurality of selected angular positions relative to the support when the housing has been rotated relative to the arbor to wind the spring motor, biasing means urging the housing in one axial direction to hold the interengaging means in engagement, the said biasing means enabling the interengaging means to be disengaged when the housing is manually forced in the opposite axial direction, the said selected angular positions of the housing coinciding with the angular position to which the arbor is urged by the spring motor, the wound spring motor unwinding and rotating the arbor and the shaft fast thereto to the selected angular position as predetermined by the angular position of the housing when the shaft is freed for rotation by the released detent mechanism, the timer having an element which shifts from a first position to a second position when the timer is set for time measuring operation and which returns to said first position when the time measuring operation is completed, means linking the timer element-- and the detent mechanism to cause the detent mechanism to hold the shaft against rotation when the element isat the second position and to cause the detent mechanism to release the shaft for rotation when the element returns to the first position so that when a time measuring operation is completed by the timer the previously wound spring motor rotates the arbor and the shaft fast thereto from the angular position which they had prior to the winding of the spring motor by the rotation of the housing to the selected angular position at which the housing was locked by the manually releasable means after winding of the spring motor.

4. A device for manually rotating the rotary shaft of a control apparatus to any of a plurality of selected positions and conditionable to automatically rotate the said shaft to any other of the said selected positions after a predetermined lapse of time, comprising a support fixed relative to the control apparatus, a releasable detent mechanism for holding the control apparatus shaft against rotation, a motor unit mounted for rotation on the support and including a stub shaft connected to the control apparatus shaft in torque transmitting relationship but axially slidable with respect thereto, a motor housing manually rotatable relative to the stub shaft and extending through an opening in the support, and a spring motor in the housing and coupled to the stub shaft, the spring motor being windable by manual rotation of the housing relative to the stub shaft when the control apparatus shaft is held against rotation by the detent mechanism, the spring motor urging the stub shaft and housing to a predetermined angular position relative to each other,

mar-249 the force required to wind the spring motor 'bein'g appreciably greater than that required to rotate the control apparatus shaft-so that when the said sha'ftisndt held against rotation by the detent-mecha'nisr'n'it is rotatable to a selected positionby the manual rotation-of the housing, stop means on thesupport, abutment means on the housing engageable with the stop means, t-hefs'topand abutment means being positioned at such relative angular locations that when'they are-intere'nga-ged the predetermined angular position to whichthe-stub shaft and control apparatus shaft connected thereto are urged is o'n'eof the selected control shaft angular positions, biasing means urging the housing in one axial direction to hold the stop and abutment means in engagement but permitting the stop and abutment means to be disengaged when-the housing is pushed in-the opposite axial direction, thew'ound spring motor unwinding and rotating the shafts to the aforesaid one of the selected angular --positions when the control apparatus shaft is freedfor rotation by the re- "leased detent mechanism, a timer having an element which shifts from a first position to a second position when the timer is set for time measuring operation and which returns to said first position when the "time measuring opera- 'tion'is completed, means linking thetimer elementand the detent mechanism to cause the detent mechanism to hold the shafts against rotation when the element is at the second position and to cause the detent mechanism to release the shafts for rotation when the element retur-ns to the first position so that when a time measuring operation is completed by the timer the previously wound spring motor rotates the shafts from the angular position which they had :prior to the winding of the spring motor by the rotation of the housing to the aforesaidone of the selected angular positions.

5. A device for manually rotating the rotary shaft of a control apparatus to any of a plurality of selected positions and conditionable to automatically rotate said shaft to any otherof the said selected positions after a predetermined lapse of time, comprising a support fixed relative to the control apparatus, a wheel fast to the shaft and having ratchet teeth, a pawl pivotally mountedon the support for engagement with the ratchet teeth to hold the shaft against rotation, the shaft when held against rotation by the engagement of the pawl with a tooth of the ratchet Wheel being angularly positioned at one of. the selected positions, a motor unit mounted for rotation on the support and including a stub shaft connected to the control apparatus shaft in torque transmitting relationship but axially slidable with respect thereto, a motor housing r'na'nually rotatable relative to the stub shaft and extending through an opening in the support, andaspring "the housing relative to the's'tu'b shaft, the spring motor urging the shafts and the housing to a fixed angular position relative to each other, the force required to wind the spring "motor being appreciably greater than that required to rotate the-control apparatus shaft so that when the said shaft is not held against rotation as aforementioned it is rotatable to a selected position by the manual rotation of the housing, stop means "on-the support, abutment means on the motor housing engageable with the stop means to hold the housing at fixed angular positions after it has been rotated to wind the motor, hiasingmeans urging the housing in one axial direction to hold thefstop and abutment means in engagement but enabling the stop and abutment -means to be disengaged by a manual push oftthe housing in the opposite axial direction, the stop and abutment means being sopositioned relative to each other that the fixed angular position to which the woundspring motor urges the shafts is one ofthe aforementioned'selected positions, the wound spring motor unwinding and rotating-the shafts to the said-one of the selected angular positions when the control apparatus shaft is freed for rotation, a timer having an element which shifts fromt a first position to a second position when the timerisset for time measuring operation and which returns tosaid first position whenthe time measuring operation is completed, means linking the timer element and the pawl ;to cause the pawl to engage a ratchet tooth when the element is at the second position and to cause the ,pawl to release theratchettooth when the element returns-to the first position so that when a time measuring operation is com pleted by the timer the previously wound spring motor rotates the shafts from the angular position which they had prior to the winding of the spring motor, by the Iota; tion of the-housing to the aforesaid, one of the selected angular positions.

References Cited in the file of this patent -UNITED STATES PATENTS 2,096,620 Robertson Oct. 1 9, 1937

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