US2682028A - Time switch for motors - Google Patents

Description

June 22, 1954 -J. M. LAIHO TIME SWITCH FOR MOTORS 2 Sheats$heet 1 Filed June 3, 1949 June 22, 1954 TIME SWITCH FOR MOTORS Filed June 3, 1949 2 Sheets-Sheet 2 INVENTOR.

BY JaZmerMlai/zo J. M. LAIHO I 2,682,028

or the cancelling crank Patented June 22, 1954 TIME SWITCH FOR MOTORS Jalmer M. Laiho, Skokie, Ill.,

assignor to Felt &

Tarrant Manufacturing Company, Chicago, 11]., a corporation of Illinois Application June 3, 1949, Serial No. 97,039

'7 Claims. 1

This invention relates in general to electric circuit controlling mechanism, and more particularly to a novel time switch for automatically opening a motor circuit at the end of a predetermined interval.

A principal object of the invention is the provision, in a motor driven machine having manual control members selectively operable to initiate operation of the machine and cause the closing of a switch which results in energization of the motor, of means automatically effective to open the switch to de-energize the motor at the end of a predetermined time interval after operation of the last-to-be-operated of such manual control members.

Another object of the invention is to cause the motor of a calculating or business machine to be turned oil automatically when the operator has finished using it, so that carelessness on the part of the operator cannot result in the machine motor continuing to run indefinitely.

More specifically, the present invention comprises the addition to a motor driven calculating machine, having the usual digit keys and cancelling crank as manual control members, of time switch mechanism operable to start the motor in response to actuation of any digit key and to stop the motor of a predetermined time such starting of the automatically at the end interval beginning with motor.

Another object is the provision of such time switch mechanism which will be reset automatically by each subsequent operation of a control member which is effected before the expiration of such time interval, starting from the time of manual release of the last control member to have been operated, so as to avoid unnecessary starting and stopping of the motor during the performance of any normal series of related calculations.

Numerous other objects and advantages of the invention will be apparent as it is better under stood from the following description, which, when taken in connection with the accompanying drawings, discloses a preferred embodiment thereof.

In the drawings:

Figure 1 is a fragmentary elevational view of a calculating machine embodying the instant invention, as seen from the right side of the machine, showing the usual cancelling crank and the normal position assumed by the time switch mechanism following dr-energization of the motor;

Fig. 2 is a detail rear elevation of the time switch mechanism, as seen from the right end of Fig. 1;

Fig. 3 is a fragmentary elevation similar to Fig. 1, showing the positions assumed by the various parts of the time switch mechanism upon actuation of a manual control member;

Fig. 4 is a detail view similar to Fig. 3 of the switch-opening rack and immediately associated parts, showing the positions assumed thereby just prior to automatic opening of the switch;

Fig. '5 is a longitudinal elevation of the machine, with parts omitted, as seen from the left side thereof, showing the power drive connections from the motor to the time switch mechanism and the means for actuating the latter in response to digit key operation; and

Fig. 6 is a diagrammatic view of the motor circuit.

Referring more particularly to Fig. 5 of the drawings, reference numeral 2i designates in general a calculating machine of the type disclosed in United States Letters Patent No. 2,063,962, issued December 15, 1936, and my prior U. S. Patent No. 2,410,823, issued November 12, 1946, this figure corresponding generally with Fig. 2 of each of said priorpatents. This calculating machine is provided with a plurality of denominational orders of accumulator and actuating mechanisms, the latter being mounted on skeleton frame members or partition plates 22 held together in spaced relationship by transverse tie rods 23, and registration control means including a column of digital control keys 24 for each such order which are selectively manually depressible to determine the digital degree of actuation to be imparted by their associated actuating mechanism to the accumulator. Such mechanism is fully described in said prior patents, so that a more particular description herein is not necessary, reference being had to those patents for a complete explanation of the specific arrangement of the parts and operation of this type of calculating machine, including an electric motor 44 drivingly connected by suitable gearing (Fig. 5) with a power drive shaft 45 extending transversely of the machine across the several denominational orders and comprising an element of the cyclically operable registering means of the machine.

It is sufficient for a complete understanding of the present invention to know that in this type of calculating machine, which comprises only one of many possible devices with which the instant invention may be employed, depression 3 of any digit key 24 causes its stem All to engage and move downwardly a longitudinally extending bar 28 (Fig. 5) forming part of a parallel motion device, one such device being located in each denominational order of the machine. Each bar 58 is pivoted at the front at 49 and at the rear at 51 to levers 52 and 53, respectively, which in turn are pivoted upon cross shafts or rods 54 extending through the partition plates 22. Completing each parallel motion device is a link E5 which is pivotally connected at 58 to the front lever 52 and at 51 to the rear lever 53. It will thus be seen that depression of any digit key 24 will cause forward movement (to the right in Fig. 5) of the lower link '55 of the associated parallel motion device, and it is this resulting forward movement of the stud 56, comprising the pivotal connection between the link 55 and the lever 52, that is employed in connection with the present invention, in a manner to be fully described hereinafter. For convenience, all of the reference numerals so far used herein are the same as those applied to the same parts in my said prior Patent No. 2,410,823.

As is customary in this type of calculating machine, other registration control means also are provided comprising means for zeroizing or cancelling any registration from the accumulator. In the prior patents previously referred to, such zeroizing of the accumulator is accomplished by rocking the supporting frame of the accumulator to disengage the latter from its actuating gears, and the specific mechanism for accomplishing this cancelling function is fully disclosed in U. S. Letters Patent No. 1,357,748, issued November 2, 1926. The zeroizing mechanism of the instant machine is substantially identical to that described in this latter patent, so that only so much thereof is illustrated in Fig. 1 herein as is necessary to a complete understanding of its structural and functional relationship with the present invention. A short transverse shaft '10 (Fig. l) is journaled in a suitable bearing in the right hand side plate 22, and the lower end of a zeroizing control handle or cancelling crank '11 is secured to the outer end of this shaft. A segment 12 is fixed upon the inner end of this short shaft 10, and a link 13 pivotally interconnects the segment 72 and a depending lever "14 that is pivoted at '15 on the machine frame. These parts are numbered the same as their counterparts in Patent No. 1,357,748, and as explained in detail in said patent, forward movement of the upper end of cancelling crank 11 (counterclockwise movement thereof viewing Fig. 1) will move the link '13 forwardly to swing the depending lever '14 in a counter-clockwise direction to actuate a suitable rock shaft which effects the gear detraining and accumulator zeroizing previously mentioned.

Pivotally secured at its forward end to this depending lever 14 and the link 13 is a rearwardly extending link 121, the rear end of which is pivotally connected to the upper end of a lever 153. This lever 153 is fixed intermediate its ends on the right hand end of a cross shaft 152 having suitable bearings in the skeleton frame members 22 and extending transversely through all denominational orders of the machine. The lever 153 is urged in a clockwise direction (viewing Fig. 1) by a spring 155 secured thereto at one end, adjacent the lower end thereof, and at its other or forward end to a cross shaft 156 mounted in and extending through the frame plates 22. These several parts are numbered herein the same as their counterparts which are fully disclosed in U. S. Letters Patent No. 2,021,393, issued November 19, 1935. Counterclockwise movement of the cancelling crank '11 from its normal position of Fig. 1 to effect zeroizing of the accumulator, in the manner noted above, thus will carry the link 12'1' forwardly to impart counter-clockwise movement to lever 153 from its position of Fig. 1 to its position of Fig. 3, and also considerably beyond the position of Fig. 3. The resulting rotation of shaft 152, as speifically explained in said prior Patent No. 2,021,393, releases error control or key locking mechanisms which may have been set by mismanipulation of one or more digit keys 2 1. It is the rearward movement of the lower end of this lever 153 thus resulting from operation of the cancelling crank '11 that is employed in connection with the present invention.

To adapt this otherwise old lever 1'53 for use with the novel mechanism comprising the instant invention, its lower end has been lengthened and provided with an outwardly extending tooth 261. This tooth 201 cooperates with a notch 282 (Fig. 1) in the forward end of the lower arm of a two armed pawl 203 pivotally mounted at 204 on a link 205. A grasshopper type of spring 2136 mounted on the pivot 2M engages the underside of the link 205 at one end and the forward edge of an upper arm 221 of the pawl 233 at its other end. The lower arm of the pawl 263 has a lat eral extension or shelf 20B normally engaging the lower edge of the link 295 to limit clockwise movement of the pawl 2113 by the spring 206. A stud 2119 is mounted on the adjacent skeleton frame member 22 for cooperation with the upper arm 20! of the pawl 2113 in a manner to be later described.

The forward end of the link 2115 is provided with a slot 211 slidably engaging the shaft 156. A spring 212 is connected at its forward end to the cross shaft 156 and at its rear end at 213 to the link 205 to normally maintain the latter in its position of Fig. 1 with the rear end of the slot 211 in abutting engagement with the shaft 155. Adjacent its rear end, the link 2115 is pivotally connected at 21 1 with the upper end of a lever 215 in turn pivotally mounted at its lower end on a cross shaft 216 mounted in the frame plates 22. The rear end of the link 2% is pivotally connected in any suitable manner at 211 with the forward end of a link 213 in turn pivotally connected at its rear end with an upwardly extending arm of a bell crank lever 219. This lever 219 is pivotally mounted on a cross shaft 221 on which shaft the forward end of a latch pawl or holding detent 222 is also pivotally mounted. This holding pawl 222 is provided with a laterally extending stud 223 which is held in engagement with the under surface of the lower, rearwardly extending arm of the lever 21!] by a grasshopper type spring 224, the latter being mounted on the cross shaft 221 and engaging the under surface of the stud 223 at one end and the forward edge of the upper arm of the bell crank 21!! at its other end.

A stud 225 extends laterally of the machine, but not inwardly sufficient to contact the lever 219, for movement-limiting engagement with the forward end of a switch-opening ratchet memher or slide bar 226. As best seen in Fig. 2, an auxiliary frame is provided for supporting those parts of the instant time switch mechanism mounted at the rear of the machine, which comprises a pair of vertical side plates 221 secured together in parallel spaced relationship by suitable bolts and spacer sleeves, as indicated at 228, this sub-frame assembly being mounted in any desired manner on the inner side of the right hand frame plate 22, and the outer plate 221 carries the laterally extending stud 225. The outer plate 227 of this time switch sub-frame alsois provided with a pair of inwardly extending shouldered studs 229 which are slidably engaged, respectively, by a pair of horizontally disposed slots 23! formed in the ratchet slide bar 225. This ratchet slide bar 226 thus is mounted for horizontal sliding movement, and it is provided on its lower edge with a plurality of ratchet teeth 232 adjacent its forward end for cooperation with the holding pawl 222. The pawl 222 normally engages the forward one of these ratchet teeth 232 to maintain the ratchet slide bar 226 in its rearmost position of Fig. 1, wherein an insulated roller 233 mounted on the rear end of the slide bar 226 and extending laterally therefrom engages against the lower end of a spring contact member 234 to maintain the contact thereof out of engagement with the contact of a second depending contact member 235. These contact members 234, 235 comprise a switch connected in series with the motor 44. As shown in Fig. 6, the contact member 234 is connected to one side 23% of a suitable source of electrical energy, the other side 23? of such supply being connected to one side of the motor 44, and the other side of the latter being connected by a lead 238 to the other contact member 235. It will be under stood that any desired circuit arrangement other than that illustrated in Fig, 6 may be employed, so long as the closing and opening of the switch comprising the contact members 234, 235 results in the energization and de-energization, respectively, of the motor 44.

Referring again to Figs. 1 and 2, the upper ends of the contact members 234, 235 are rigidly mounted in a block 239 of insulating material which is secured intermediate its ends by rivets 2, or the like, to a bracket 242 comprising an upwardly and rearwardly extending end portion of the outer side plate 221, the inner plate 221 terminating at its upper rear end adjacent the forward edge of the insulating block 239. Such mounting of the contact members 234, 235 on this insulating block 239 preferably is accomplished by providing the contact members with lateral extensions at their upper ends (Fig. 1) in the form of ears 243 extending therefrom rearwardly and forwardly, respectively. Each of these cars 243 is connected to the insulating block 239 by a pair of rivets 244, the upper one of which preferably is hollow and formed at its inner end as a socket to receive the ends of the leads 236 and 238, respectively (Figs. 2 and 6).

A transverse shaft 245 extends between the sub-frame plates 22'! adjacent their upper edges, being suitably secured thereto in any desired manner, upon which the upper end of a dependin lever 246 is pivotally mounted. As best seen in Fig. 2, this upper end of the lever 246 is reversely'bent to provide a saddle-like hub portion having laterally spaced lugs through which the shaft 245 extends to insure lateral stability of the lever. A spring 24'! is connected at its rear end to this lever 24B below the shaft 245 and at its forward end to a shaft 248 extending transversely through the machine. The lower end of the depending lever 246 is maintained by this spring 241 in engagement with a stud pin 249 extending laterally from the ratchet slide bar than its associated second roller 25in.

so mounted on-this gear 26i 6 226. Also mounted pivotally on the shaft 245 is a bell crank lever 25! which, as seen in Fig. 2, is provided with a laterally extending, reversely bent hub portion engaging the shaft in the same manner as the hub portion of the lever 246. These hub portions of the levers 246 and 25| are so dimensioned as to be pivotably confined adjacent each other between the inner surfaces of the side plates 221 to prevent lateral movement of the levers. The upper arm of the bell crank lever 25! extends forwardly and is connected at its forward end to the upper end of a spring 252, the lower end of which in turn is connected to a suitable stud extending inwardly from the outer sub-frame plate 227. The lower end of the depending arm of this bell crank lever 25l terminates adjacent a shouldered stud 253 extending between, and suitably mounted in, the sub-frame plates 22! (Fig. 2'). Above this stud 253, the lower end portion of the lever 25! has a stud shaft 254 mounted therein which extends outwardly from the lever and pivotally supports a pawl 255 at its outer end which is disposed in vertical alignment with the ratchet slide bar 225 which it is adapted to move rearwardly of the machine. Mounted on this stud shaft 254 is a "grasshopper type spring 256, one end of which engages the forward edge of the lever 25| and the other end of which engages the lower edge of the pawl 255 to urge the latter in a counterclockwise direction (Fig. 1) on the shaft 254 to engage the rear end thereof with actuating teeth 25'! provided on the under edge of the ratchet slide bar 225. This slide-actuating pawl 255 is provided with a depending tail piece which cooperates with the transverse stud 253, in a manner to be later described in detail.

Intermediate its ends, the depending arm of the bell crank lever 25I is provided with a later-- ally extending lug 25% (Figs. 1 2) having a rear surface parallel with the adjacent rear edge of the lever 25E and extending therefrom inwardly of the machine, and an upper edge (Jig. 4) sloping downwardly toward the main. portion of the lever 25!. This rear surface and upper edge of the lug 258 function as cam surfaces and cooperate, respectively, with a first cam roller 259 and a second cam roller 255 of each of two pairs of such rollers mounted on the outer side of a gear 25L As best seen in 1, this gear 26l'is rotatably mounted upon a horizontal shaft 262 extending between, and supported the sub-frame plates 22?. The said first cam rollers 259 of each of the two pairs of rollers 255', are disposed diametrically opposite each other, as are the second cam rollers 23% of each such pair of rollers, and each roller 259 is mounted at a greater radial distance from the shaft 232 The gear 264 is actuated by a pinion 2E3 meshing therewit (Fig. l), which is rotatably supported on a s table shaft 263 secured to the sub-frame plates 221. A gear 264 is similarly mounted on this shaft 263' and is rigidly connected to the pinion 253. This gear 264 in turn meshes with a pinion 265 secured to the power drive shaft 45. Since the motor 54) through the gear train illustrated in Fig. 5, drives the power drive shaft in a clockwise direction (viewingFig. l), the gear 251 likewise is rotated in clockwise direction, through the agency of the pinion 255, gear 264 and pinion 263; any desired gear ratio may be employed between the power drive shaft 55 and the gear 26!, and the cam rollers 259, 260 are that they will assume 7. substantiallytheirpositions--of Fig; liafter the motor 44 has been de=energized andt-the several parts driven thereby have come--to rest. As shown in Fig; 1,: pawl 255'thenwill be-disengaged from ratchet slide bar'226.

The means for .releasing1the' ratchet slide bar 226-"in response 'to actuation of the cancelling crank 1| comprises the lever'l53; which is swung from-its normal posit-ionof Fig; l to that of Fig. 3 by virtue of themembers 16,12, .13, 14 and=l21 interconnecting: it with the cancelling-prank 1 l the tooth 26! on this lever 153,- the: pawl-.263, links 265mm 2 i6, andcthe leverr2 [6, which, when thus moved to their positions of Fi 3,- release theholding pawl 222 from the ratchet slide bar 226; Since "the pawl 255 normally is in its disengaged positionof Fig.: 1 at .this'ti-me, spring 261 thus will be permitted to. swing lever 246 clockwise from its position 'of Fig'i. l to slide the ratchethar 226-toits position of-Fig: 3, through the agency of stud pin 246: Such forward-movement of theratchet slide-bar 226-is limited by contact with the stud 225. Additional time switch controlmeans are provided-,..which will now bev described, comprising: mechanism for similarly releasing the ratchet slide bar 226 in response to actuation of armor thedigitkeys 24-of the machine:

Referringto Figs 5, an upstanding finger 266 is provided in each denominational order of the machine forcooperation at its1upper end wi-th thevassociated stud 56 which comprises the front pivotbetween the link 55 and' the lever 52 of the keyeactuated parallel motiondevice of= that order. Thelower ends of each of these fingers .266'are crimped, or otherwise suitably rigidly-secured, to a rock shaft 261 extending transversely acrossthe machine. i the present embodiment of the in venti'on, this shaft 261 is illustrated as being rectangular in cross section, and His rotatably mounted at 266 in any suitable manner at each end in a supportingplate 269.- These end plates 26!! are supported by the crossshaft I56 and an adjacent transverse tie rod 23. Consequently,

depression of any one of the digit keys 24 -will cause the finger 266 in that denominational order to be swung forwardly at its upper-end from its full line to its broken line position of Fig. 5.

Referring now to Figs. 1 and 3, the rock shaft 261 is provided adjacent its right hand end with an upstanding lever 21! secured thereto at its lower end in similar manner-to thefingers 266. The upper end of this lever 211 is pivotally connected to the forward end of a link 212, the rear end of which is pivotally connected to the upper arm of a bell crank lever 213. The bellcrank lever 213 is pivotally mounted on a shaft 214 extending transversely through the machine, and is'providedat its lower end with a laterally extending stud pin 216- This pin 215 normally engages the forward surface of a shoulder "216 formed on the upper edge of the 'link- 265 adjacent the forward end thereof. When: the fingers 266 are in their normal full line positions of Fig. 5, the lever 21!, link 212 and bell -crank 216 are disposed in their full line positions ofFigs. l and 3. Forward rocking of any of the fingers 266 in response to depression ofa digit key 24, as previously described. thus will move these parts 2'H--213 to their broken line positions-of Fig. 3, which results in rearward movement of the link 265 by the pin 215 to its position of Fig. 3, which isthe same actuation ofthis link 2635 as that eifected in. response toforward movement of the I cancelling; crank 11 This "is: truewbecause such forward movement oi cancelling crank 1| results in swinging of the lever I56 from its position of Fig. 1 to that of Fig 3, whereby its tooth 26i cooperating with the notch 262 will move the pawl 263 and the link 265 rearwardly. During the final increment of such movement of the link 265- in response to forward swinging of the cancelling crank it, the upper arm 261 of the pawl 263 will strike the stud 269 to impart counter-clockwise movement to the pawl relative to the link 265 to disengage the notch 262 from the tooth 261. These parts are shown in Fig. 3 in the positions assumed just prior to such disengagement, and complete forward swinging of the cancelling crank i 1 will impart additional counter-clockwise movement to the lever l53 from itsposition of Fig. 3. Consequently, even though the cancelling crank 14 be held inits forward actuated position, tie link 265 and connected parts will be returned from their rearmost-positions of Fig. 3 by thespring 2 2 to their normal positions of l, with the top edge of the main armor the pawl 263 underlying the tooth 26!. As differentiating from such actuation of the link 265 in response to manual operation of the cancelling crank 11, this link 265 and its connected parts will not be returned to their normal positions. of Fig. 1 by the spring 2H. following-their actuation in response to depression of a digit key 24 until the latter leased.

Such rearward movement of the link 265, in response either to actuation of a digit key 24 or the cancelling crank 11, will release the latch pawl or holding detent 222 from the teeth 232 of the ratchet slide bar 226 in response to the resulting movement of the bell crank lever 2!!) from its position of Fig. l to that shown in Fig. 3. Since the pawl 255 normally is held out of engagement with the teeth 251 of slide bar 226because spring 252 :maintains this pawl and the hell-crank lever 25l in its position of Fig. 1, such release otthe holding pawl 222 from the'teeth 232 results in forward slidingof the ratchet bar 226 onthe studs 226 under the influence of spring 25 which urges the lower end of the lever 246 forwardly, until the forward end of the-ratchet slide bar 226 strikes stop pin 225. These several parts thus assume their position of Fig. Bupon actuation of a-machine control key,andthe forward movementof the ratchet slide bar 226-per mits closing of the switch, comprising contact members 2362 nd. 235, to energize the motor M. It will be readily understood, of course, that the holding pawl 222 .willwbe returned to engaging relationship with the rearinost of the teeth 232 immediately thereaften'either as the "cancelling crank 1t passes approximately the middle of its forward swinging movement, or upon manual release of the digit key 24, the depression of which instituted disengagement of the pawl 2 22.

As previously explained, all of the several parts of the instant time switch mechanism normally are disposed in their positions of: Fig. 1. In response to @the' above described energization of the motor :44; the large gear 261 is rotated-in a clockwise direction fromthis normal position. The. first cam rol1er'259 of the leading uppermost pair of rollers 259'; 26!] illustrated in this figure thereupon moves the lug 258 forwardly to swing the bellcrank lever 25iclockwiseabout theshaft 2'45-and against the actionsof'spring 232 to a positiorrto the left of that shown. in Fig. 4. This:forward movement of 'thelower end'fof the lever 25f carries-thestud'shaft "-254 forwardly and permits the spring 256 to lift the nose of pawl 255 into engagement with the lower edge of ratchet slide bar 226. Continued rotation of gear 26! carries the leading cam roller 259 beyond the lug 258 and moves the second cam roller 26!: of this pair to its position of Fig. 4. Immediately upon disengagement of the first cam roller 259 from the lug 258, the spring 252 functions to return the bell crank lever 25! in a counter-clockwise direction about the shaft 245 to its position of Fig. 4, wherein the nose of pawl 255 engages the rearmost tooth 25'! of ratchet slide bar 226. The second cam roller 260 is provided to assist the spring 252 and positively insure complete return movement of this lever 25! to its position of Fig. 1. During such final increment of return movement of the lever 25L thus positively eil'ected by cam action of roller 265 against the upper cam edge of lug 258 from the position illustrated in Fig. 4, pawl 255 is moved rearwardly to slide the ratchet bar 225 rearwardly the distance of one tooth 251, whereupon continued movement of these parts results in disengagement of the pawl 255 from rack bar 225 by virtue of engagement of its tail piece. against rod 253. In the meantime, the holding pawl 222 has been moved out of engagement with the rearmost or first tooth 232 and into engagement with the second such tooth to maintain the slide bar 225 in such intermediate position (as shown in Fig. 4)

As illustrated herein, three such latch teeth 232 and two actuating teeth 25'] are provided on the slide bar 22%. Consequently, repetition of such incremental movement rearwardly of the bar 226 eiiected by the second pair of cam rollers 2-59, 260 as they in turn actively engage cam lug 258 in the continued rotation of gear 26!, will move rack bar 226 from its position of Fig. t back to its normal position of Fig. 1. During the last portion of such incremental rearward movement of the slide bar 226, the insulated roll 233 will move switch member 234 rearwardly out of contact with switch member 235 to break the circuit and cause de-energization of motor 44. The overrunning of the motor and members driven thereby after such de-energization, due to the momentum of the parts, will insure return of the several members to their position of Fig. 1. It will be readily understood that the particular gear ratio herein illustrated as obtaining between pinion 265 and gear 26!, and the specific number of latching and actuating teeth 232 and 251 shown, may be varied to obtain any desired predetermined time interval between closing of the motor switch in response to manual operation of a machine control member and automatic reopening of such switch. In other words, depending upon the particular construction, normal mode of operation and operating cycle time of the specific machine in which the instant invention is to be incorporated, the person employing this invention may so design the several parts, as hereinbefore described, as to obtain the most satisfactory predetermined delayed shut-oil of the motor. The specific embodiment of the invention herein illustrated and described greatly facilitates its incorporation in the type of calculating machine disclosed in the referenced prior patents, since it makes use of the mechanism old therein and is particularly adapted for such incorporation by virtue of the assembly of the major portion of the novel mechanism in the sub frame 22?, 228. It will be understood, however, that it is not intended to limit the scope of this invention to the specific embodiment herein disclosed, nor to its use only with that type of machine illustrated in such patents.

It is thought that the invention and its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction .and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described and illustrated in the drawings being merely a preferred embodiment.

I claim:

1. In a time switch for a motor operated machine having a plurality of manually operable members for selectively controlling machine operation and a motor controlling switch normally maintained open by a switch-opening member, spring means for retracting said switch-opening member from normal position, a latch pawl normally engaging said switch-opening member to prevent retraction thereof by said spring means, a link pivotally connected to said pawl and spring-urged to normally maintain the pawl in latching engagement with said switch-opening member, and connections actuated by said manually operable members to move said link in response to actuation of one of said manually operable members to disengage said pawl from said switch-opening member and automatically releasable from said link to efiect ire-engagement of said pawl with said switch-opening member, whereby each successive operation of any one of said manually operable members will disengage said pawl from said switch-opening member.

2. A time switch according to claim 1, wherein said connections include a toothed lever rockable by a said manually operable member, a bell crank lever pivotally mounted on said link and having a first arm spring-urged into engagement with said toothed lever and a second arm upstanding from said link, and a stationary stop against which said second arm is moved to disengage said first arm from said toothed lever at the end of the latching pawl disengaging movement imparted thereby to said link to enable immediate return of said link to normal position.

3. In a time switch for a motor operated machine having a plurality of manually operable members for selectively controlling operation and a motor controlling switch normally maintained open by a switch-opening member, spring means for retracting said switch-opening member from normal position, a latch pawl normally engaging said switch-opening member to prevent retraction thereof by said spring means, a link pivotally connected to said pawl and springurged to normally maintain the same in latching engagement with said switch-opening memher, a rock shaft having a plurality of upstanding fingers operatively associated respectively with said manually operable members, and connections interposed between said rock shaft and said link for actuating the latter to disengage said pawl from said switch-closing member upon actuation of any one of said manually operable members.

4. In a time switch mechanism for a motor operated machine having a motor controlling switch normally maintained open by a slide mechanism manually releasable to effect closing of the switch, means for cyclically advancing said slide mechanism in step-by step movements to re-open said motor controlling switch, comprising a gear train driven by the machine motor and including a driven gear, a lever, an advancing pawl pivotally mounted on said lever and springurged toward engagement" with said slide mechanism,xstationary stop means, spring means for moving said lever. to'impart advancing movement to .said pawl andv subsequently to move said pawl into engagement with said stop means to efiect disengagement thereof from said slide mechanism, and cooperatingcam means carried by said driven gear and said lever' for imparting retractive movement to said lever to tension said spring means.

5. Time switch mechanism according to claim 4, wherein said cam means includes a member carriediby said driven gear operable after tensioning and release of said spring means to positively insure complete pawl advancing movement ofsaid lever.

6. Time switch mechanism for motor operated calculating machines which'have an electric circuit through the motor,-a switch ior'controlling said-circuit, and a plurality ofcontrol members selectively operable manually to control'operation of the machineycomprisinga ratchet member normallyengaging said'switch to maintain the same in open position, 'means constraining said ratchetmember for-movement out of engagement with said switch, detent means normallyengaging said'ratchetmember to prevent movement thereof by said constraining means, link mechanism operable in response to manual actuation of a said'contrormember to-disengage said detent' meansfrom said'ratchet member to enable. closing of said switch by said constraining means, spring means operable to return said link mechanism followingsuch' actuation of said control..member to re-engage-said detent means with said ratchet member, a ratchet member driving pawl, a second spring means normally maintaining saidpawl out of engagement-with said-ratchet member, and means cyclically operable bysaid motor to snccessively' tension said second spring 'means and release the same to actuate; said driving pawl to move said ratchet member toward switch opening position against the action of" said constraining means.

'7. Time switchmechanismaccording to: claim 6, wherein said cyclically operable means comprises a cam member operable after tension and release of said second spring means to'pos'itively effect" complete actuation of said driving pawl.

Refercnccs Cited in. the file Of this Patent

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