US2496598A - Electrically controlled platen operating mechanism for time stamps - Google Patents

Description

Feb. 7, 195% F. s

ELECTRICALLY CONTROLLED PLATEN OPERATING MECHANISM FOR TIME STAMPS Filed Feb. 11, 1944 4 Sheets-Sheet l F. Q. RAST ON Feb. 7, 1950 2,496,598 ELECTRICALLY c TROLLED PLATEN OPERATING 7 MECHANISM FOR TIME STAMPS 4 Sheets-Sheet 2 Filed Feb. 11, 1944 ENVENTOR MA/ ATTORNEY 2,496,59 EN OPERATING F@b. 195@ F. Q. was ELECTRICALLY CONTROLLED P MECHANISM FOR TIME sum 4 Sheets-Sheet 3 Filed Feb. 11, 1944 MA k E 5...... 5 i I I k.

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ELECTRICALLY CONTIQCSLLED PLATEN OPERATING v MECHANISM FOR TIME STAMPS Filed Feb. 11, 1944 4 Sheets-Sheet 4 IVENTOR QRNEY Patented Feb. 7, 1950 ELECTRICALLY CONTROLLED PLATEN OP- ERATING MECHANISM FOR TIME STAMPS Frederick Q. East, Rochester, N. Y., assignor to International Business Machines Corporation, New York, N. Y., a corporation of New York Application February 11, 1944, Serial No. 521,933

12 Claims. 1

This invention relates to time stamps and more particularly to the type in which the impression is effected by a power operated means, in contradistinction to the type wherein the impression is effected manually.

The invention primarily concerns the platen operating mechanism and it has for its principal object the provision of an improved mechanism that will provide the clean sharp print without reliance upon the use of a solenoid for directly actuating the platen.

While solenoids of various purposes have been found efiicient in their function, their use usually required the provision of a non-repeat platen operating mechanism, which expedient is eliminated by the present invention. Furthermore, to secure suiiicient power to operate the platen to provide the.clean sharp print, solenoids of sumcient capacity were required, and required considerable electric power for their complete energization. Since the circuits of such solenoids were directly in the circuit which included the paper actuated contacts, difficulties in maintaining clean and efiicient contacts resulted. In the present invention all of such difiiculties are completely avoided since the platen operating mechanism is operated by a spring operated drive, which energy is constantly stored and maintained for use as a main power drive as the time stamp is called into operation.

A supplemental object of the invention is the provision of an electrical motor and driving con nections between the electric motor and the spring drive which automatically maintain the spring drive completely wound.

A still further object is to provide an improved arrangement by means of which the unwound condition of the spring drive is detected and a rewinding operation by the electrical motor operating is automatically effected.

A still further object is to provide a novel form of means to prevent over-winding of the spring drive and possible resultant damage to the parts.

More specifically the last named object is attained by the provision of a worm wheel drive intermediate the motor and the spring drive. During the time that the spring drive is being wound the worm wheel functions in a normal manner and this normal operation is derived by balancing the power to coil the spring against a balancing spring, which latter provides a thrust bearing for a floating shaft of one element of the worm wheel drive. In the rewinding operation when the power required to wind the coil spring is greater than the balancing spring, then the worm wheel drive functions in another manner,

2 the operating characteristics being such that the floating axis shifts laterally to terminate the operation of the electric motor and the spring rewinding operation.

Another object of the invention is to provide an arrangement which enables the operation of the mechanically operated platen operating means without damage of parts in the event that the platen is obstructed or prevented from receiving its invariable printing movement.

A still further object of the invention is to provide an escapement mechanism which comprises a mechanical control for the platen operation. 4

A still further object is to provide an electromagnetic control of the aforementionedescapement mechanism and operatively coordinated in such a manner that a small electromagnet or solenoid can be used for initiating platen operations.

A still further object ensuing directly from the provision of a small electromagnet is to provide a circuit closing contact device operable by the paper inserted in the machine. Since, in the present machine, the electromagnet does not require large currents for its energization, contact troubles are greatly minimized if not completely eliminated.

Other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of example, the principle of the invention and the best mode, which has beencontemplated, of applying that principle.

In said drawings:

Fig. 1 is a view in side elevation of the right side of the machine, relativeto the operator, the lower casing being shown broken away to show the interior parts constituting the present improvement. i

Fig. 2 is a longitudinal sectional view taken on the line 22 of Fig. 1 and shows-in plan'the parts constituting the present invention.

Fig. 3 is a transverse sectional view taken on the line 3-3 of Fig. 1 which is substantially the mid-portion of the machine.

Fig. 4 is a transverse sectional view taken on the line 4-4 of Fig. 1 and shows the construction of the spring operated power drive of the present invention.

Fig. 5 is a view in side elevation taken on the line 55 of Fig. 1, showing particularly the escapement operated means for effecting the reciprocation of the platen by the spring power drive.

Fig. 6 is a view taken on the line B--'& which is substantially at the front portion of the machine and shows particularl the platen and the related operating mechanism.

Fig. 7 is a detached view showing the construction of the escapement mechanism as well as the electromagnetic: controletherefor.

Figs. Band 9 are views of certain of the parts shown in Fig. 7 but in moved position.

Fig. 10 is an electrical wiring diagram of the electrical instrumentalities involved in thepresent invention.

Fig. 11 is a detached view showing'the parts associated with the platen operating-mechanism.

Fig. 12 is a plan view of ttheizpaper actuated contact operating mechanism.

The entire time stamp .is ,mounted upon.a base casting 18 which provides the entire supporting means for the novel platen operating mechanism. The latter mechanism is enclosed :by a casing Hjf(Eig.il)'. .Byzmeansrofr-a.pivot .pin 12. carried :by the:bottom-casing=theprinting head l3=sis: pivotallyimounted. The printing head [3 constitutes the type awheelsthewclock controlled drive, 'time indicating mechanism, ribbon feeding mechanism,*etc., all of :which are fully shown and described' in detail in the patent to LSC. Bishop -'et-a1.,"No.- 1;?981583, dated -Mar'ch 31, I931. The me0hanism-inthe printingihead is not shown herein since the present "invention relates to "novel means '"foroperating and controlling the impression taking" means; or "platen. For an understanding of the present invention, it is sufilcientto understand that the time print ing means consists of a group of wheels 1.4 (Figs. .1 and 11) which.are preferablyftime and date printing wheels toprint such information upon the papers to be stamped. The printing head I3 has a separate enclosing casing (Fig. 1) and. it will vbe :observed that .they front portions vof..the.casings l5..and=ll..are.so disposedas to .provide a; deep unobstructed opening HLfor receiving the cpapers .to ..be..stamped. .Of course, theprinting :head [-5 -is..-suitably latched .to the base portion of the machine .so -that .the .time

and "date iprinting --.wheels M are immovable to outline aszthe 'platen H, that is rectangular,

and suitably :guides theaplaten in; itsreciprocating movement. The platen I1 is, as-sshown in Fig. 1, normally below. the. uppenhorizontahsurface: of the :casing: l I' to provide an unobstructed positioning of itheepapersutoibe stamped.

The preferredform'of means which provides the operative connectioni'betweenthe platen .operating mechanism -and the: platen is 'best shown in Figs. 5,6and 11. Referringto Figs. 5 and 6, itwill' be seen that upstanding from the-base H] are brackets 22- and 23in which is journalled a shaft 24 and secured to the shaft -is' an -arm25 and, as shown 'inFig. 11, arm 25' projects within a slotZGa of the cylinder '2lland underlies the bottom of the stem 19 of the'platen H. To the rock shaft '24 there is secured 'an'arm 2B and loosely mounted on the rock shaft 24 is a plate 2! and interposed between the arm 26 and the plate 2'! is a normally tensioned spring 28. Spring 28 draws arm 26 against plate 21 until edge 21a strikes spring stud 26a carried by the arm 26. Obviously, when the plate 2! is rocked counterclockwise, the earm 26 wvill be rocked through the interpose'd spr-ing ZBin'the same direction and accordingly the shaft 24 will be rocked in a similar direction to cause the arm .25 to elevate the platen" to effect the percussive printing action. In the position of the parts shown in Fig. 5 cam portion 29 of the plate 27 rests on the top of one of the series of operating studs 30. Such studs are equiangularly disposed on an escapement disk 3| and are coextensive with the step of movement given to the escapement disk3l for each operation of the machine. Therefore, in the angular movement of the escapement disk 3|, controlled in the manner to be subsequently explained; the'stud t'o in-cooperation with thecam portion"29' will, in such step "of movement, "positively rock-the: plate 2? counterclockwise, andthrough spring 28 rockingarm 26, shaft .24, and arm .25 inthe'same'counterclockwise direction. will positively force the impression blockil'to impress the paper to be stamped against theprintlng .wheels.

In the actual operation .of .themachine the step of movement given'to'fthe escapementqdisk 3 I by .a spring -operated .drive .is very rapidvand accordingly .the platen '11 .is operated .with a hammer .blow, .to thereby,provide the desired clean impression. .Itmaybepossible that the platen will be stoppedcbythe. type wheels .before the .plate 21 is given the extentof movement providedby the-step ofvmovementiof the escapement vdisk 3]. .However, no damage will be caused-because it. is obvious that further movement of theplate E21 :afterzthegplaten has been obstructed will merely tension the spring -28 until. the operatingstud 30xfinally clears; the :cam portion 29 ofithe :platet2'l.

The position; of-the; parts 330,-" as the "operating stud '30 2715 32110111; to: clearv'the: plate 21,: is shown in Fig. 11,. it'tbeingl "obvious that :a I slight additional clockwise movement of the escapement -'disk' 3 twill cause the stud torclearz the cam por tion 29, whereupon the platen is now'free to drop'to'normal position by its own weight, and parts connected thereto. "Ifso desired, an -suitable tensioni-ng means may be attached to the platen or any parts which are given a similar movement to positively restorethe platen to its normal position. However, "by proper dimensioning of the partsrandiselection of suitable materials,gravity alone .may be depended upon for restoration of. the .platen to normal.

Means. to .effect an. e uiangular step ,of. movement of .the.escapement.disk;3l .for each operation. of the, machine, .that is, ,for.-each stamping or printing of the inserted. paper,..will now .be described,;,particularly in connection -with:Figs. 5, 7,-8,'-9,l 0 and 11.

'r'lhe escapement-disk ".3 I .l'S iprovided with escapement teeth 32-which-are disposed around the periphery to correspond with the angular .positioning'of'the operating'studs 30. Associated with the-teeth '32 is anescapement mechanism which consists of a positively operated escapement pa\vl 33'=and a'sprin operated stop pawl 34 and to providethe movement of such pawls there'is'provided a solenoid'35. It will be observed from Figs. 2' and 5 that this escapement control is mounted on the base ID of the machine.

The solenoid 35 has a core 36 having a reduced portion 3'! receiving a lug 38 of a link 39. An elongated slot 40 of the link 39 receives a stud 4| secured to the base of the machine, thereby guiding the link 39 in its movement effected by the solenoid 35 to the right and its retraction by a spring 42 connected to the aforementioned link 39. The link 39 is connected to the positively operated escapement pawl 33 by a pin 43. A stud 44 passing in the base |IJ provides the pivotal mounting for the stop pawl 34 and the escapement pawl 33. It will be noted that while the stop pawl 34 is superimposed with respect to the escapement pawl 33 the latter has a bent-up portion 45 (see also Fig. 5) which brings the terminations of the pawls 33 and 34 in the same plane and therefore in a position to intercept one of the teeth 32 of the escapement disk 3| A sprin 46 is interposed between the stop pawl 34 and the positively operated escapement pawl 33 and normally, that is to say, after a previous operation of the platen, one of the teeth 32 of the escapement disk 3| normally abuts a shoulder 4! of the escapement pawl 45. (See Fig. 7.)

Referring to Fig. 10, reference numeral 48 represents electrical contacts which may be manually closed, or by the paper to be stamped or printed when it is inserted in the machine. From the simple electrical circuit in Fig. it is clear that closure of such contacts will energize the solenoid 35 and the latter will attract its core 33 to move the link 39 to the right as shown in Fig. '7 to rock the escapement pawl 33 clockwise, withdrawing the shoulder 41 from the tooth 32 with which it is engaged.

Assuming now that the spring drive has been wound up sufficiently to drive the escapement disk 3|, the latter is now free to rotate to operate the platen in the manner previously described.

Fig. 8 shows the position of the parts wherein the escapement pawl 33 has been rocked sufficiently to release the escapement disk 3| and in such position the sprin 46 is tensioned so that a shoulder 48 of the stop pawl 33 bears against the side of the tooth 32. The escapement tooth 32 will, of course, pass by the shoulder 48 as the escapement disk 3| is moved a single step. When the link 39 is at its extreme position at the right, the increased tension of the spring 45 will rock stop pawl 34 sufficiently so that shoulder 48 is now in the path of the following tooth 32. (See Fig. 9.) Ultimately the tooth 32 will abut the shoulder 48 to stop the disk 3|. When the solenoid 35 is deenergized, spring 42 will now shift link 39 to the left. Since the shoulder 41 abuts the shoulder 48, this will rock the stop pawl 34 slightly in a counterclockwise direction, withdrawing the shoulder 48 from an abutment relationship with the following tooth 32, whereupon the disk 3| will move very slightly until the following stop tooth 32 engages the shoulder 41 of the escapement pawl 33. The parts are now in the position shown in Fig. '7, ready for a subsequent operation.

The spring operated means for providing the stepby-step movement of the escapement disk is preferably provided by the usual form of spring barrel, well known in clock mechanisms, typewriters, etc. A somewhat similar means is preferably utilized herein and comprises a coil spring 50 (Fig. 4) which, as it is permitted to uncoil,

provides the power to rotate the escapement disk 3|. One end of the coil spring is secured to a winding shaft 5| by a pin 52, the other end of the coil spring 53 enveloping one of the series of studs 53. The coil spring is mounted in a cage which comprises the escapement disk 3| and a parallel circular disk 54. The disks 3| and 54 are spaced apart by spacin tubes 55 (Figs. 1 and 4) through which pass fastening screws 53. At each end of the screws 55 the aforementioned operating studs 30 are screwed. By this arrangement a rigid spring carrying cage is provided.

The winding shaft 5| may be rotated in a clockwise direction (Fig. 4) by any suitable supplemental power operated means to store up the necessary spring power but preferably this is rovided by an electric motor 51 which is carried by a sub-base frame 58 fastened by any suitable means to the base plate III. This motor may be of any suitable design adapted to perform efficiently by the current supply with which it is connected and have sufiicient torque to rotate shaft 5| to wind up the coil spring 50. The gear driving connection intermediate the motor 5'! and the spring cage will now be described.

The armature shaft of the motor 51 has secured thereto a worm wheel 59 (Fig. 3) meshing with a worm gear 63 carried by a shaft 6|. The latter is rotatably supported by a pair of brackets 62 extending upwardly from the base plate It]. A supplemental support plate 33 is also provided to give additional support. Between the brackets 62 the shaft 6| is provided with Worm wheel threads 64 in mesh with a worm gear 35 secured to a worm wheel support shaft 66 which extends at right angles to the shaft 6|. The shaft 66 is a short shaft and is supported by a pair of brackets 31, one of which is shown in Fig. 2, both being supported by the base plate H3. Shaft 66 has secured thereto a pinion 38 meshing with a gear 69 which is fastened to the spring winding shaft 5|. The above described gearing aside of having a special function to be subsequently described provides a reduction gearing between the motor 51 and the spring winding shaft 5|. The gearing is so arranged that with the proper direction of rotation of the, motor the shaft 5| will be turned clockwise. Since normally the escapement disk 3| is held by the aforementioned escapement mechanism, it will be evident that in rotating the spring drive shaft 5| clockwise the coil spring 59 will be wound but movement to the spring cage including the escapement disk 3| will be effectively prevented by the cooperation of the escapement pawl 45 with a tooth 32 of the escapement disk 3|. Through the gearing aforementioned, the coil spring 50 is wound until it has been wound sufllciently, whereupon a certain operation will be effected to prevent over-winding of the spring and possible damage to any parts of the machine. The automatically operated mechanism for effecting this function will now be described in detail. This arrangement is best shown in Fig. 3.

Integral with the shaft 6| is a disk or flange 10 and interposed between the flange 19 and a washer H which is loose on the shaft 6|! is a coil spring l2 encircling the extremity of the shaft 6|. The spring 12 is normally under compression so that the spring will urge worm gear against plate 63 and the washer H against the balls of a ball bearing race 14 which is carried by the support plate 63. The expansive strength of spring 72 is so selected as to prevent any transverse movement of the shaft 6| to the left while the coil springis being woun'dup i from .a completely uncoile'd condition andthe worm drive 64-1 65 then functions asnamormalrdrive until a: predetermined wound condition is reached. PAS the shaft'ilil (Fig. 4) :is continually rotating in a clockwise direction Z -tO wind the coil spring :50 from .a completely. unwound condition; the power required by the motor .Will "be increased until at arnearly wcund condition of the spring coil 50, or even when its mam'mum wound condition obtains, further. winding'operations will be efie ctivelypreventedirby the tollowing operation.

When :this' predeterminedlloard ionsshaft'rfil is reached the worm wheelfi liis stillattempti-ng to rotate the-worrrrgear=65cnow-heldrelatively stationary, o1" nearly so,r.but :is unable to do so when the::pcwer :to .drive. shaft-:Efiexceeds the force of therba'lancing'spning:T2. 'At this timewor-m wheel threads Meeting-on worm-geanllS will now cause shafhfil to be feditorthe "left as it: is being rotated-since shaftzBl uiSifBGEl'sOsSO move due to thesabsencetofa thrusti hearing at :the left. .This lateral movement -of shaft-*Ghcontinues until a point is reached' whereathe flange "H! ;of shaft 6 l, in cooperation withaa stud "T .ofalever l6, rocks said lever was to openaan=electricswitch to disconnect the current supply from the motor. The electrical ::-means for initiating the operation of the-motorfil 'when'a completely unwound condition of the-sprin drive is discernedwill now be explained.

Pivotally' mounted on one of the studs 53 (Fig. 4)-.is'a feeler levenBil .urged bye spring 81 so that it ispressed 'at all-times-against the outermost convolution of the spring-50. .Whenthespr-ing is completely unwoundas shown i-nvFig. 4 ahead portion 82 of the feeler leverrltlliwillyduring a certain steppingmovement of the spring cage, makecontact'withand operate'alever 83 secured to. a transverse shaft-84 suitably journalled. in .a recess of the base plate l0. The-rock 'shaft84 carries (at its extremity :a-switch-operatingarm 85. The rocking of theshaftr84 iseffected .upon a completely unwound condition: of the spring 58- and the rocking of the-lever-.-85 to'therig-ht (Fig. 6) will push inwardly the on switch button :86 of any-suitable form of switch. The switch"S:is-preferably of -a type known as the Muf switch constructed as shown in the Patent No. 1,780,758, dated-November 4,1930. .The elementary'parts of: this switch are diagrammatically shown in'Fig. lO-Wherein it-will be noted-that the contact carrying switch blade :81 'is-anchored at 88;the-characteristics of the preferred form of switch being such that when the buttonBB is depressed slightly by the operating-arm 85 the spring-blade :81 will snap towa contact making position to close contacts-89, the latter beingin series with the electrical motor 57 to thereby initiate the operation of the motor resulting in the winding of the coilspring 50.

"When :a completely wound conditionof the springs!) 'is' eifected, or to the-point desirable, it will be recalled that the flange of shaft 6| is'moved laterally to the left shown in -Fig. 3, and by oontactwiththe button will rock the bell crank lever 76. This leveris pivoted at 96 (Fig. 2) and the front 'portiondll of the bell. crank lever mus-positioned adjacent-the off button 92 of the switch S. This will then result in the opposite snapping of the switch blade 87 to open contacts 89 to cut the .currentsupply from the motor 51.

Hence, the m0tor-51-wi1l be cut in and out of the circuit :automatica-lly the .number of times 1 this is-eifected, depending'of. course, on the. number of times that thestamp is :used for printing operations. Such operations are effected automatically without ;any attention on the'part of the operator.

Any suitable means either manual. or paper controlled, may be'provided to close the contacts 48 to initiate the imprinting operation. However, the preferred form of means will nowlbe described.

'The contact operating mechanism is constructed. as a-unitand is carried {by a bracket 95. Pivotally mounted on the bracket 95 by a pin 98 is a'bell crank lever96'9'l which is provided with an" integral upstanding [paper actuated'finger. 99. Thelatter is disposed lathe-opening i6-to be actuatedcbythe' paper inserted in the machine to be stamped. The portion '91 of the bell crank lever has pivoted at H10 a lever lfll provided with a-shoulder. I02, normall engaging the extremity of a contact'operating arm I03. A spring I04 interposed between the lever till 'and'the bracket QS-maintains-the normal :position shown inFig. l2. Obviously,:when thepaper strikes the finger 99 its continued movement tothe rear will-rock the bell crank 1eVerB6'91 :and' through the lever lOl arm 4-03 will'xberocked to close the-contacts 48.

It will be recalled thatclosure of-suchcontacts will energize the solenoid 35 to initiate the operation of i the spring driven "esca pement 'mechanism to-eifect the printing operation.

From-Fig.- 11 it will be seen that a downwardly extending lug'lflE integral with the lever Hills in the path of; the teeth.32 of the escapement disk 31. "lhe release of the escapement disk 31 for a step will cause one of the teeth 32.to engage the lug H15 to rock the-lever l-fll, thereby unlatchin'g the arm N13. The resiliencyof theoperated contact operating blade is suficient sot that'contacts 48 will. thereby open, irrespective of the fact that the paper which has been printed willwbe maintained in contact with the finger 99 to keep-the bell crank lever- 96"9l' in'rocked rposition. Hence, automatically operated mechanism operates-to open the contacts-48 to v.deenergize the solenoid 35 to enable the proper performance of the escapementmechanism; previously described.

awhile there have been shown and describedand pointed out the fundamental novel features of the invention as applied to asingle modification, it will be understood that various omissions and substitutions andc'hanges in theform and details of the device illustrated and in its operation may 11631185618:flGY-thOSG SklHQd in theart without departing from thespirit of the invention. It is the intention; therefore, to be limited only as in dicatedby the scopeofthe following claims.

What :is claimed is:

,1.rI-na platen"operating-mechanism for a time stamp, the combination of'a'spring operated motor, an escapement member driven'by said spring motor,-a platen actuating member, an electromagnetically controlled 'escapement mechanism for causing: said escapement member to o erate said platen actuating member to operate said platen to effect a paper stamping. operation, and a circuit for the electromagnet"controlling said escapement mechanism and including contacts actuated bythe .palper inserted in the machine for a stamping operation to energize the electromagnet.

.2. Ina time stamp, a-spring operated motor having the customary operating springmounted upon a spring w-indingiarbor, an' escapementvdisk I carried by said arbor and operatively connected to said operating spring, a mechanical escapement mechanism cooperating with successive teeth of said escapement'disk to release said disk for a predetermined extent of rotation, means operated :by said disk for actuating a platen of the time stamp, a solenoid for controlling the escapement mechanism upon its energization, a circuit for said solenoid including contacts actuated to closed position to energize the solenoid by the paper to :be inserted in the machine to be stamped, and means operable by a part of the escapement disk for enabling said contacts to take an open [position irrespective of the maintained insertion of the paper within the machine after a stamping operation.

3. In a platen operating mechanism for a time stamp, the combination of a spring operated motor, an escapement member driven by said spring motor, a platen actuating member, an electromagnetically controlled escapement mechanism for causing said escapement member to operate said platen actuating member to operate said platen to efiect a paper stamping operation, a circuit for the electromagnet controlling said escapement mechanism and including contacts closed by the paper inserted in the machine for a stamping operation to energize the electromagnet, and means actuated by said escapement member to cause said contacts to assume an opened position to ,deenergize said electromagnet.

4. In a time stamp, a spring operated motor having the usual operating spring mounted upon a spring winding arbor, an escapement disk carried by said arbor and operatively connected to said operating Spring and having operating .projections thereon, a mechanical escapement mechanism comprising a stop pawl and an escapement pawl cooperating with successive teeth of said escapement disk to release said disk for a predetermined extent of rotation, an arm operable by said operating projections when said disk escapes, an arm for actuating a platen of the time stamp, interconnecting means between said arms for causing said first named arm to actuate said platen actuating arm when said disk escapes, a solenoid for operating the escapement pawl upon its energization, a circuit for said solenoid including contacts actuated to closed position to energize the solenoid .by the paper to be inserted in the machine to be stamped, and means operable by the escapement disk for enabling said contacts to take an open position irrespective of the maintained insertion of the paper within the machine.

5. A platen operating mechanism for a time stamp comprising a spring motor, an escapement member driven by said motor, an escapement mechanism comprising an escapement pawl and a stop pawl, the first named pawl for releasing said escapement member to be driven by said motor to an extent predetermined by said stop pawl, an actuating member for said platen, operating means operable by said escapement member, and flexible means interconnecting said operating means and said actuating member to enable an invariable operation of said escapement member to the predetermined extent irrespective of the possible obstruction of the platen.

6. A platen operating mechanism for a time stamp comprising a spring motor, an escapement member driven by said motor, an escapement mechanism for releasing said escapement member to be driven by said motor to a predetermined extent, an actuating member for said 10 platen, platen operating means operable by said escapement member, and flexible means interconnecting said operating means and said actuating member toenable an invariable operation predetermined by said stop pawl, an actuating member for said platen, and operating means intermediate said escapement member and said actuating member and operable by said escapement member each time the latter isreleased for effecting the operation of said platen to printing position 8. A platen operating mechanism for a time stamp comprising a spring motor, an escapement member driven by said motor, an escapement mechanism comprising a stop pawl, and an escapement pawl movable to a position for releasing said escapement member to be driven by said motor to an extent predetermined by said stop pawl, an actuating member for said platen, operating means intermediate said escapement memher and said actuating member and operable by said escapement member each time the latter is released for effecting the operation of said platen to printing position, a solenoid for operating said escapement pawl to releasing position, and a circuit for said solenoid including paper actuated contacts for energizing said solenoid when the paper to be stamped is inserted in the machine to a stamping position.

9. In a time stamp, a spring operated motor having the customary operating spring mounted upon a spring winding arbor, an escapement disk carried by said arbor and operatively connected to said operating spring and having operating projections thereon, a mechanical escapement mechanism comprising a stop pawl and an escapement pawl cooperating with successive teeth of said escapement disk to release said disk for a predetermined extent of rotation determined by said stop pawl, an arm operable by said operating projections when said disk escapes, an arm for actuating a platen of the time stamp, interconnecting means between said arms for causing the said first named arm to actuate said platen actuating arm when said disk escapes, a solenoid for operating the escapement pawl upon its energization, a circuit for said solenoid including contacts actuated to closed position to energize the solenoid by the paper to be inserted in the machine to be stamped, and means responsive to the operation of the escapement mechanism for enabling said contacts to take an open position irrespective of the maintained insertion of the paper within the machine.

10. In a time stamp having a platen operable to effect printing on an inserted sheet, the combination of a spring motor comprising a power spring and devices driven by said power spring, and said devices including an escapement member; escapement mechanism comprising a stop pawl and an escapement pawl coacting with said member and operable when activated to release said escapement member so that said devices, including said escapement member, are driven by said spring to an extent predetermined by said stop pawl; an actuating member for said platen;

' and power transmitting means connecting said driven devices and said actuating member and effective to operate said platen each time said devices are driven by said spring due to the activation of said escapement mechanism.

11. Apparatus according to claim 10 and including, in addition thereto, means for activating said escapement mechanism upon the insertion of a sheet, and means responsive to the driving of said devices by said power spring to restore said escapement mechanism to its normal de-activated condition.

12. In a time stamp having a platen operable to effect printing on an inserted sheet, the combination of a driving motor operable in step-bystep fashion and including a power spring for operating said motor; escapement means coacting with said motor and operable when activated to provide step-by-step operation of said motor, one motor operating step being effected REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 917,955 Leidigh Apr. 13, 1909 1,219,325 Jones Mar. 13, 1913 1,979,208 Friden Oct. 30, 1934 2,205,516 Busse June 25, 1940

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