US3079812A - Timer - Google Patents

Description

March 5, 1963 w TIBRoss 3,079,312

TIMER Filed Oct. 10, 1958 3 Sheets-Sheet 1 March 5, 1963 w. -r. BROSS 3,079,812

TIMER Filed Oct. 10, 1958 3 Sheets-Sheet 3 3,679,812 TIMER William T. Brass, Cincinnati, Ohio, assignor to Liehei- Flarsheim, (Iincinnati, fihio, a corporation of Ghio Filed Oct. 10, 13358, Ser. No. 766,541 11 (Jiaims. (1. i i-6&5

This invention relates to a dual purpose timing device for selectively determining the duration of an operation. More particularly the invention relates to a device having two rotary members, one for small units of time and the other for large units of time, both of which can be set to initiate an operation after a predetermined time interval, and following the predetermined interval, return to starting condition ready to repeat the interval of time. In the alternative, the present invention contemplates a timer which starting at zero may be used to time an operation and at the conclusion of the operation return to zero. In many types of operations, it is necessary to time an operation for a desired precise predetermined interval and to repeat that operation for the same precise interval of time. It is also desirable to have a timing mechanism in which the precise interval of time may be preselected and be altered in accordance with the necessities of difiering situations. A precision interval timer preferably should be provided with means for setting units of time to provide a rough approximation of the desired interval and to provide means for setting fractional units of time to impart precision timing to a device.

The timer of the present invention includes two contact carriers, one driven at a slow speed for the large units of time and one driven at a faster speed which is a multiple of the speed of the other timer. Bot-h contact carriers have contacts which cooperate with contacts on adjacent dials which may be set for the desired time interval. When there is simultaneous engagement of the contacts of both carriers, the time interval has been completed and an operation is either begun or terminated as the application of the device dictates. It is then necessary to return the contact carriers to their starting positions so that a timed operation can be repeated without requiring manual resetting of the timing instrument.

In accordance with the present invention the contact carriers are returned by means of torsion springs which are strained by the rotating movement of the contact carriers. The driving means associated with the contact carriers operates through clutches which disengage at the termination of the time interval. The disengagement of the clutches will permit the torsion springs to drive the contact carriers to their starting position. However, the design of the torsion spring carrier return system presents the problem to which the present invention is particularly directed. It will be appreciated that whereas one contact carrier moves through only one revolution, the faster contact carrier for fractional units will move through a plurality of revolutions. For example, in the device to be described in detail below, the fractional units carrier may be required to turn through up to 100 revolutions for one revolution of the units carrier.

Specifically then, the invention seeks to avoid the necessity of providing a torsion spring which will return a contact carrier equally efiectively through a fraction of a revolution or through a large number of revolutions. Thus, a spring which could return the carrier through, say, 60 or 100 revolutions probably would he inettective to return the carrier completely through a fraction of one revolution or would be too impractical to use because of the great size required to wind through 100 revolutions. Alternatively, a spring which, with surety would return the carrier through one revolution could not stand the Eatented Mar. 5, 1953 strain of winding through 60 or revolutions as -a practical matter.

An objective of the invention has been to provide, in a timer of the type described above, a torsion spring system for returning rotating contact carriers to their starting positions in which the torsion springs for each carrier are not strained in excess of one revolution.

it has been another objective of the invention to provide a torsion spring return for the contact carrier of a timer in which one end of the torsion spring is connected to the timer and in which the other end of the torsion spring is connected through a slip brake to the shaft about which the car 'er rotates.

In a preferred construction, the invention comprises a timer having a contact carrier rotatably mounted on a shaft, a torsion spring connected at one end to the contact carrier, and a helical or torsion spring brake engageably mounted on the shaft and having one end thereof connected to the other end of the torsion spring, while the free end of the helical brake spring is engageable by the contact carrier to free the helical brake spring from the shaft and thereby disengage the brake. By virtue of this construction, as the contact carrier is rotated by its driving means, the torsion spring is strained sufiiciently to be able to return the contact carrier to its starting position when the drive mechanism is released from the contact carrier, the helical spring brake maintaining one end of the torsion spring fixed to a shaft during the rotation of the carrier until the free end of the helical spring is engaged. At that time the carrier torsion spring and helical spring will move as a unit with the torsion spring being maintained in its strained condition. Thus, at any instant that the carrier is released from its driving means the torsion spring will be under sufficient stress to return the contact carrier to its starting position, but the additional stress on the torsion spring will never be greater than that imparted by full revolution of the carrier.

It has been another objective of the invention to provide a drive transmission for a timer of the type described in which a motor drives both contact carriers through reduction gearing and a pair of disk type clutches mounted on a shaft, an electromagnetic operator being provided to compress the assembly of gearing and clutches in an axial direction and thereby to cause the engagement of the clutches. An electromagnetic-ally operated latch is associated with the operator to hold the clutches in engagement until the completion of a predetermined interval. The closing of the contacts on the carriers can, among other things, energize the latch magnet to release the latch and disengage the clutches, where upon the torsion springs will automatically return the contact carriers to starting position.

It has been still another objective of the invention to provide in a timer, means for rotating two contact carriers at a speed ratio of the order of :1. This speed ratio is obtained by providing a fixed gear and a rotatable gear adjacent the fixed gear. The rotating gear is connected to the slow contact carrier and has a slightly ditferent number of teeth from that of the fixed gear. A planetary gear, driven by the fast carrier drive rotates about the two adjacent gears causing the rotatable gear to move very slowly about its axis.

These and other objectives of the invention will become more readily apparent in the following detailed description taken in conjunction with the accompanying drawings in which:

PEG. 1 is a perspective view of the timer constructed in accordance with the invention;

FIG. 2 is a cross-sectional view taken along lines 2-4 of FIG. 1; Y

'FIG. 3 is a fragmentary top plan view of the invention;

FIG. 4 is an exploded perspective view thereof;

FIG. 5 is a fragmentary detailed view of the clutch operating mechanism; and

FIG. 6 is a cross-sectional view talten along lines 6-6 of FIG 3. r

The timeris mounted on a frame 10 having perpendic} ula'r posts 11 to which. a shaft 12=is fixed mounted. At each end ofithe'shaft 12 are irotatably'mounted knurled dials l3 and 14 hearing indicia15 and 16 respectively. The dial l3is used todetermine' the units of time through whichthetimerioperat es and the dial 14 isused to determine the fractional units of time through which the timer operates. ':In the embodiment illustrated, the ratio of the dialsis 100:1. i i

As best illustrated in FIG. 2, the dials each carry a pair :of contacts 17 and 18 respectively which cooperate with bridging-contacts 20 and 21fixed to the contact'carrier's Hand 23 respectively. The timer. determines the completion of the prescribed interval of time by the simultane 'ous bridging .ofthe contacts associated withthe dials'13 .and.14.-

The bridgingcon'tacts 20 and 21 are semi-circular and the contactsi- 17 and 1815f each pair are spaced tan'gularly by about 170? so that there is a closing-of the contacts for each carrierover an interval of approxi .mately1 I Referring to FIGS. 3. and 6,-.the contact carriers are driven. at 'theirrespective speeds by a gear-system including-a gear 24meshing witha'gear 25 fixed to carrier 22, and=a gear 26. engaging'gearJ-27- fixed to carrier 23. The gears 24 and 26 are driven throughclutches 28- and 29 respectively, which are operated by an-axially =movable hollow shaft '30 slidably mounted on a rod-314F166). Theclutch 29' connects gear 26to a gear- 32 which is directly. dn've'n by a'small gear-33 fixed tea shaft '34 driven by a synchronous motor '(not shown). -A-'p1anet gear 35 rotatably mounted'on the gear 32 cooperates-with a sun. gear 36 fixed to: rod 31 and'hav-ing-99 teeth and a sun gear 37 having 100 teeth. Sun gear 37 is fixed "on a journal b'earing'38 which is 'rotatablymounted on rod 3l. The cooperative-action of planet gear 35 rotating about sun gears 36and "37- provides a 10021 gear reduction betwe'enagears 32 and 37 ;Since clutch 28 connects sun gear {3710 gear 24,*the ratioof the speed-of gear 26 to the speed-of gear 24 is 100:1 Further, since the gear connectionfrorn gears 24 'and'26 to their respective contact carriers is identical the contactcarriers will have a 100:1 speed ratio. 1 I

i It should beunderstood that the 100:1 ratio of contact carriers is specified, in part, to demonstrate the problems attending thereturnof a contact carrier to its starting position after it hasrotated. up to- 100 revolutions.- 'The inventiomof course, has application to other systems utilizing diitering ratios.

'- The c1utches128and29 each include a plate 40 fixed to the respective gears 24 and-26 to which they are connected and aplate 41. The plate 41-.controling gear 24 is fixed on journal bearing 38. The shaft 39 to which gear 24 and its clutch plate 40 are fixed is axially slidable in a post 42 at one end thereof, the rod 31 being mounted a plate43' at the otherend of .the assembly. A lever" 44' pivoted at 4510 the post 42fbearsagainst the shaft 30 as at '46 and is engaged at its other end at.47 by pins 48 fixed to a'plate 49. The plate 49 is fixed to an armature 51 of an 'electromagnet '52 (FIG. Energi zation of electrom'agnet 52 will move the .pla te..49 tothe left to pivot the lever 44 in' a clockwise direction to cause the clutches to engage; whereby the b 'fit f f 5 may be driven at their 100:1, ratio. In'it's extreme leftmost position a latch 53' spring hiased'in an up'warddirection, engages a notch 54in the plate 49', thereby holding the plate-49 in its left-most position against the actidn' or the spring. The latch 53 is mounted on the armature 55 of a second electromagnet 56. Energizationof electromagnet 56 pulls the armature downward to disengage the latch 53 from the notch 54, thereby releasing the pressure of plate 49 and lever 44 .ontheclutch plates.

Contact Carrier. Return Mechanism Contact carrier 22 has a pin 60 c'arried by the gearZ'S which 'is fixed to the contact ca'rrierf22. {The pin 60 is connected to one endofa spirallywound torsion spring 61, the other end of which is fixed to a collar 62 which is :in turn fixed by a set screw V6?: to theJ'shaft-IZ. i Another .pin 64 is carriedby the .gear on the contact carrier'22 and cooperates with one of a pair of spring'biased'stop's :65. The spring biased stop .permits the "pin topass when the contact carrier is rotatedin the normaltiming direc-. tion but blocks the movement of the .contact carrier'wl1'en it. is returned in'the reverse direction under. the 'actionfof the torsion spring. The position of engagement of the pin 64 with the stop 65- is. the starting for zero position of the contact carrierl22. I It can be seen that when theclutch 28 is engaged and .the timer gears are driven, the,tor'sion spring 61will :be

, strained and. will, remain in. the "restrained: condition broughtabout by rotation of the contact carrier 22.

Whenthe clutch; 28 is disengaged, however, the contact carrier. is .free to .rotate and under. the' aetion'jof'th tor- -sionv spring willybe driven around to its starting position and stopatsthat starting position by the; engagemen't of the pin 64 with the stop 65. '1Sincecontact'carrier22 will .normallyrotate nornore than'one revolutiomitis possible to utilize the comparatively 'simplej torsion spring return described above. T. Because the fractional units contactcarrier 23 rotates through a plurality I of1rev.o1utions before 'the carrier 22 completesa'revolution, a more diflicult problem of rem ispresented, requiring a difierent torsion spring returning system. 3 The return sy'stemfor can-ieri23* includes a'pifi 70 hired to thegeari 27 by which 'carrieri23 'is"driveti;

A torsions'pringfil is fixed at one 'endto the pin70 'an'd at the other endqto a collar'72. .JIhe collart72 system, howeven-is freely rotatable withre'spe'ct'to the shaft 12 but is connected to shaft 12 by means of a' 'helic'al brake.spring 73fixedat one end74' to the'collar 72;"The

brakev spring, in its. relaxed condition will have "an inside diameter slightly less than the outside diameter of the shaft -12 whereby thejspring will normally frictionally; grip the shaft. 'I'heother end 75 of the brake spring extends radially outward from the shaft 12 ton position'inwhich v it is engageable' by the pin .70.. .When the"end 75 is engaged the springwill' be. strainedin'a'directionto 'i'n' crease slightlyitsginside diameter whereby the brake spring can slip with respect to the shaft 12: A washer 'ldspaces the end 75 of thespring from a snap washer-"177 fixed to shaft 12 thereby preventing the leg 75 from becoming lodged in the open ends of washer 77. *Washe'rs78a'nd 79 are loosely mounted on collars 62 and '72 r'espectively to maintain springs ,61 and 71 in .proper alignment; A

pin 80 on gear27, similar to the pin 64 on gear 25,""co+ operatesfwith spring biased stop so that the carrier is free for. continued rotation in the driving or timing direction, bu 'on lspring returmis hlocked from passing the'zere'pasinbn.

Th Operation of the carrierreturn is as follows; when the clutch 29 is engaged andthe gear- 27 is being-rotated by'the drive means, the pin 7 0 will tend to tighten the tor sion spring 71 and thereby -to rotate collar ,72.. "The tendency of the torsion spring 7 1 to rotate the collar 72 will be resisted by the tightening of thefhelical brake springf73 on the fixed shaft 12 Asthegear. 27 continues to rotate, the .pin 79 will he carried into engagement "with the free end of .the helical spring andwill tend to untwist the helical spring, thereby freeing it from its braking'engagement with the shaft 12. torsion spring will remain in the strained condition imparted to it by the angular movement of the pin 70 but will not be rained further since the end of the torsion spring connected to the collar 72 will be rotated with the pin 70 for as many revolutions as are necessary to complete the timed interval.

At the completion of the timed interval, clutch 29 will be disengaged freeing the gear 27 and carrier 23 for rotation. The strain imparted to the torsion spring 71 will be suificient to drive the contact carrier to its starting position at which pin Silwill strike stop 65 to bring the carrier to rest.

The timer unit described above is suitable for use with two different types of timing operations. For the one operation, the timer is set for a particular interval of time, started, and at the completion of the interval of time, the contacts of both carriers will be closed and the electromagnet 56 will be energized to unlatch and disengage the clutches. Depending upon the particular type of operation involved, other circuits may be energized by the simultaneous closing of the two sets of contacts for the operation of'signal lights and the like.

In the other basic type of operation of the timer, the timer will be used for measuring time intervals. For example in the counting of the radiation of radio-active isotopes, a measureof activity can be obtained by determining the length of time a material emits a predetermined number of roentgens. With this type of operation, the timer would be set to zero and would be started when a suitable counter is exposed to the material being measured. When the counter has indicated that the radiation has reached the predetermined quantity, the timer motor would be stopped and the length of time read directly. Thereafter, by energizing the electromagnet 56, the carriers would be returned to zero through disengagement of the clutches under the action of the torsion springs thereby placing the timer in readiness for a new, similar operation.

in a general manner, while there has been disclosed in the above description, what is deemed to be the most practical and efiicient embodiment of the invention, it should be well understood that the invention is not limited to such embodiment as there might be changes in the arrangement, disposition and form of the parts without departing from the principle of the present invention as comprehended within the scope of the accompanying claims.

Having described my invention, I claim:

1. In a timing device, a dial resetting mechanism comprising, a fixed shaft, a dial member rotatably mounted on said fixed shaft, a collar rotatably mounted on said fixed shaft, a torsion spring connecting said dial member to said collar, a slip brake connecting said collar to said shaft, and means for disengaging said slip brake when said torsion spring is strained through at least a portion of a revolution and maintaining the strain on said dial member, whereby said torsion spring will return said dial member to starting position upon completion of a timing operation.

2. In a timing device, a dial resetting mechanism comprising a fixed shaft, a dial member rotatably mounted on said fixed shaft, a collar rotatably mounted on said fixed shaft, a torsion spring connecting said dial member to said collar, a helical spring brake on said shaft and connected at one end to said collar, said brake gripping said shaft when said collar is urged by said torsion spring to rotate in the direction of said dial member and means for disengaging said brake when said torsion spring is strained through at least a portion of a revolution and maintaining the strain on said dial member, whereby said torsion spring will return said dial member to starting position upon completion of a timing operation.

3. In a timing device, a dial resetting mechanism comprising, a fixed shaft, a dial member rotatably mounted on said fixed shaft, a collar rotatably mounted on said 6. fixed shaft, a torsion spring connecting said dial member to said collar, a helical spring brake on said shaft and connected at one end to said collar, said brake gripping said shaft when said collar is urged by said torsion spring to rotate in the direction of said dial member and means on said dial member engageable with the free end of said spring brake to relase said brake upon engagement of said free end, whereby said torsion springwill not be strained greater than one revolution of said dial member and will return said dial member to starting position upon completion of a timing operation. v

4. In a timing device, a dial resetting mechanism comprising, a fixed shaft, adial member rotatably mounted on said fixed shaft, a collar rotatably mounted on said fixed shaft, a torsion spring connecting said dial member to said collar, a helical spring brake on said shaft and connected at one end to said collar, said brake gripping said shaft when said collar is urged by said torsion spring to rotate in the direction of said dial member, means on said dial member engageable with the free end'of said spring brake to release said brake upon engagement of said free end, whereby on said torsion spring will not be strained greater than one revolution of said dial member and will return said dial member to starting postion upon completion of a timing operation, and means providing a slidable friction connection between said free end of said spring brake. and said shaft to assure braking action.

5. In a timing device, a dial resetting mechanism comprising, a frame, dial member, means rotatably mounting said dial member on said frame, a torsion spring connected at one end to said dial member, a slip brake means connecting the other end of said spring to said frame and means for disengaging said slip brake means when said torsion spring is strained through at least a portion of a revolution and maintaining the strain on said dial member, whereby said spring will return said dial member to starting position upon completion of a timing operation.

6. In a timing device, a dial resetting mechanism comprising a frame, a dial member, means rotatably mounting said dial member on said frame, a torsion spring connected at one end to said dial member, means connected to the other end of said spring to cause said spring to be strained upon rotation of said dial member sufficiently to return said dial member to a predetermined starting position, said means preventing straining said torsion spring greater than one revolution.

7. A timing device comprising, a fixed shaft, a pair of timing members rotatably mounted on said shaft, drive means for rotating one of said members at a predetermined speed and the other of said members at a speed which is a predetermined multiple of said predetermined speed, clutches between said drive means and said members, a first torsion spring connecting said slower member to said shaft to return said member to starting position when said clutches are disconnected, a collar rotatably mounted on said fixed shaft, a second torsion spring connecting said faster member to said collar, a slip brake connecting said collar to said shaft, and means for disengaging said slip brake when said second torsion spring is strained no greater than one revolution and maintaining the strain on said second torsion spring whereby said torsion spring will return said faster member to starting position upon completion of a timing operation.

8. A timing device comprising, a fixed shaft, a pair of timing members rotatably mounted on said shaft, drive means for rotating one of said members at a predetermined speed and the other of said members at a speed which is a predetermined multiple of said predetermined speed, clutches between said drive means and said members, a first torsion spring connecting said slower member to said shaft to return said member to starting position when said clutches are disconnected, a collar rotatably mounted on said fixed shaft, a second torsion spring conspam ifas ti r men lben-a sys'tem foi' Said-11 1611 11238 atf'thelrrprbpei' relative speeds comprising, a .pair of coaziial gearsdrivably engaging said: :o'tata'ble .mcnibers,

said driving gear and mesh ing with, said: z's'un, .fgears; and

means fo eifee'tin' 'en'g'ag'emefltfif saifi. clutch plates. j 111.- A sy sfem aee' rdin tb claim, 10 -in which elutc'h enf ageme n'n ean eqmpfises means for Cbmpre ssi'ng Q'the abbvewdescribecl "assembly of gearsand clutch plates jt'ogetherin'afi axial airebtion. w

'lg rerehggg c iiea iii the aren' -this pateg't I MT D STATES'MTENTS" j

Claims (1)

1. IN A TIMING DEVICE, A DIAL RESETTING MECHANISM COMPRISING, A FIXED SHAFT, A DIAL MEMBER ROTATABLY MOUNTED ON SAID ON SAID FIXED SHAFT, A COLLAR ROTATABLY MOUNTED ON SAID FIXED SHAFT, A TORSION SPRING CONNECTING SAID DIAL MEMBER TO SAID COLLAR, A SLIP BRAKE CONNECTING SAID COLLAR TO SAID SHAFT, AND MEANS FOR DISENGAGING SAID SLIP BRAKE WHEN SAID TORSION SPRING IS STRAINED THROUGH AT LEAST A PORTION OF A REVOLUTION AND MAINTAINING THE STRAIN ON SAID DIAL MEMBER, WHEREBY SAID TORSION SPRING WILL RETURN SAID DIAL MEMBER TO STARTING POSITION UPON COMPLETION OF A TIMING OPERATION.

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