US2902134A - Full stroke positive feed printing platen - Google Patents

Description

Sept. 1, 1959 2,902,134

J. w. DobswoR'rH FULL STROKE POSITIVE FEED PRINTING PLATEN Filed Nov. 15, 1957 2 Sheets-Sheet 1 INVENTOR. JAMES W. DODSWORTH- AGENT Sept. 1, 1959 J. w. DODSWORTH 2,902,134

FULL STROKE POSITIVE FEED PRINTING PLATEN Filed Nov. 15, 1957 2 Sheets-Sheet 2 mummy .7/ INVENTOR. JAMES w. DODSWORTH" AGENT Patented Sept. 1, 1959 2,902,134 I FULL STROKE Posrrrvn FEEn PRINTING PLATEN Application November 15, 1957 Serial No. 696,877

11 Claims. (Cl. '197-114) The present invention relates to listing calculating machines and the like capable of recording factors and results of calculations on work sheets entered around the usual printing platen of such machines. However, it is to be understood that the invention may be applicable to other types of machines capable of recording data on paper.

Machines of the above type generally incorporate a rotatable paper supporting platen which is automatically and incrementally advanced as an incident to operation of the machine in order to permit listing of various values in sequence along different lines of the work sheet. Usually the platen is also provided-with a twirler knob or the like for rotating the platen in either direction, whereby the same can be manually advanced or retarded to thread a work sheet into or out of the machine or to provide a relatively large blank space for the purpose of entering identifying data or thelike. I

Heretofore means for automatically advancing the paper platen usually include a ratchet wheel and a pawl for advancing the ratchet Wheel wherein the pawl is caused to be automatically withdrawn gradually from the active tooth of the wheel while the paper feed stroke is being effected. Thereafter a suitable spring tensioned locating means acts to assist momentum of the parts and complete the line space operation. Since a release of the operating pawl from an active tooth of the ratchet wheel if occurring too soon would cause an understroking of I the platen feed and 'if' held in engagement too long would cause overthrowing of the feed it is necessary that close manufacturing tolerances and adjustments be maintained in such devices.

Aprincipal object of the present invention is to provide a more simplified'and improved platen feed means for effecting a full stroke positive line space operation of the paper platen for such machines.

Another object is to provide a line spacing means wherein the operating pawl will maintain engagement with the ratchet wheel of the platen throughout the entire active range of platen advancement.

Another object of the invention provides automatic means which at the completion of a feeding stroke will act to positively lock the platen against an overthrow.

Still another object is to provide means which will act following the completion of a full stroke positive feed operation of the platen for automatically conditioning the feed means whereby the platen may thereafter be manually operated in either direction. r

The manner in which the invention is carried out will be readily understood on reference to the following specification when read in conjunction with the accompanying drawings, wherein: I N

Fig. l is a sectional View illustrating the mechanism for automatically advancing the platen as an incident to a machine operation, the parts being shown in normal condition of rest. f

Fig. 2 is a detail view showing the platen feed pawl at the end of a forward stroke and preparatory to effecting a multiple line space operation of the platen.

Fig. 3 is a view similar to Fig. l and with the parts shown just completing a full operating stroke of the platen advancing means.

Fig. 4 is a detail view with parts of the platen feed devices shown in a position taken just at the end of an operation of the cyclic means therefor.

Fig. 5 is a detail perspective showing parts of the automatic feed devices, together with a control knob for manually operating the platen in either direction.

The improved line space device disclosed herein has been shown for convenience with relation to a printing platen mounted in a shiftable carriage of a listing calculator of the type such as disclosed in Patent No. 1,946,572, issued to Loring P. Crosman on February 13, 1934, as modified-by the disclosure of Patent No. 2,748,916, issued to Harvie J. Duke on June 5, 1956. It will be obvious, I however, that said line spacing device is equally adaptable for operation in conjunction with such type machines.

and other printers equipped with either a shiftable or a non-shiftable platen carriage.

A work sheet or tape having been first inserted into the platen carriage 10, between the platen 11 and the.- usual pressure rollers 12, is thereafter advanced around; the platen to bring the desired printing line to proper position relative to the printing hammers 13 by the: manual rotation of a suitable twirler knob 14, in the; well-known manner.

Pivotally mounted at 15 within the right and left end framing of the carriage is a transverse bail 16 held nor-- mally in raised position, against tension of spring 17, by: means of a roller ls fast to the rearward .arm of a three: armed ope'rating lever'19. Lever 19 is fulcrumed upon;

forward arm'thereof having engagement with a cam lever 22 fast upon a transverse shaft 23. Also fast upon shaft;

23 is an'arm 24 having link connection 25 with a rock arm 26fast to alrock shaft 27. A reciprocatory forward 7 and return movement of rock shaft 27 is effected either by suitable handoperated lever means, in known manner, or by motor clutch control means, such as set forth in Patent No. 1,946,572 of reference. During a forward movement of rock shaft 27 the cam 22, through means of arm 26,-link 25, arm 24 and shaft 23, will be rocked in a clockwise direction. In the first part of said movement of cam 22 the roller 21 is engaged by a high point 22 of the cam provided for the purpose hereinafter described. Thereafter said roller will follow the falling edge of said, cam to permit a clockwise operation of the lever 19, under influence of a spring member 28 secured at one end to an upwardly extending arm of said lever and at the opposite end thereof to a stud 29 secured to the fixed shaft 20. Upon clockwise operation of lever 19 v 32. Said pawl has a lateral lug 33 adapted for engaging the teeth of a'ratchet wheel 34, fast to the platen shaft 35,'for effectingrotation of the platen 11, as in the manner to be described. r g

It is desirable that the platen \11 be normally free 'for an operation in either direction by the manual control knob 14. xspe'cial'means are provided therefore to holdthe feed pawl 32 normally rocked in' a clockwise position I a spring 37. Saidspring is connected to the lower end portion of the flipper 36 and to astudwhich acts to support a roller 38 on'the forward arm ofa locator pawl39,

pivotally supported upon an eccentric stud 40 mounted: in the carriageend frame. A suitable spring 41. for pawl 39. acts to hold roller 38 in yieldable engagement with the.

teeth of ratchet wheel 34 for holdingthe platen in properrotational position. Roller 38 serves also as a stop means for the flipper 36, so that a cam surface 36 of the flipper.

Will act to support lug 33 of the feed pawl32 .f ree of ratchet wheel 34.

During the, above described downward operation of bail 16 the pawl 32 moves forwardly with arm 16' and lug 33 moves oil the cam surface 36' and into a full depth of engagement permitted with a selective one of the teeth of ratchet wheel 34, as illustrated in Fig. 2. While Fig. 2 illustrates the pawl 32 in a position for effecting a two tooth step operation of the ratchet wheel. 34, suitable well-known means for limiting the extent of operation of;

bail 16 may be provided to control a non-operation or one or more steps of line space operations of the platen. 7 It will be noted at this time that a portion of lug 33 now extends below a pointed forward end of the cam edge 36' of the flipper 36. Upon a subsequent return movement of rock shaft 27 the parts earlier described will act to restore roller 18 and the bail 16 upwardly, rocking arm 16 ina clockwise direction and returning thereby feed pawl 32 rearwardly. During such operation lug 33 of pawl 32 remains in full depth engagement with theactive tooth of ratchet wheel 34 and will in the present instance, effect a positive rotation of said ratchet wheel for two complete tooth steps of its movement in advancing the,plat en,11. In the final tooth step of operation lug 33 acts also to engage the pointed end of flipper 36 and imparts thereby a clockwise movement to said flipper against tension of the spring 37, for the purpose hereinafter to be described. 7 Operation of the feed devices in advancing the platen for a full stroke of operation may materially increase the danger of overthrow thereof and specialmeans are provided therefore operable under control of the feed devices topositively lock the ratchet wheel 34 and thereby platen 11 at substantially the point of completion of thefeed stroke and prevent any farther rotation thereof.

Loosely mounted upon pivot stud of the bail 16 is an upwardly extending lever 42 having an eccentric stud connection 43 with the arm 16 of said bail. Mounted at 44 to the lever 42 is a yieldable latch 45 positioned normally by lever 42 out of cooperation with a lug 46 on the rearward arm of locator pawl 39, earlier described. During the above described operation of bail 16 arm 16 thereof in effecting a forward and return operation to feed pawl 32 will synchronously therewith effect a forward and return movement to latch 45. Thus during any multiple tooth operations of ratchet wheel 34 the locator pawl 39 is free as roller 38 moves over the teeth of the ratchet wheel. a completion of any final tooth step of operation of the ratchet wheel 34 and while roller 38 moves over a tooth thereof the pawl 45 engages the forward surface of lug 46 and will yield counterclockwise. Just prior to the maximum point of a return movement of the feed pawl 32 and arm 42, occasioned by engagement of cam edge 22'; with the operating roller 21 in a return operation of rock cam 22, roller 38 will have entered a tooth space of ratchet wheel 34 sufficiently to release the forward face of lug 46 from latch 45. Upon release from lug 46 latch 45 snaps to a position over said lug and will immediately thereby lock the locator 39 and roller 38vand .thuseffect The timing is such, however, thatnear roller 21 from the cam point 22 ,to permit a slight. retraction of the parts, during which latch pawl 45 is withdrawn from lug 46 and is again at the normal position of rest shown in Fig. 1.

It will be recalled that at the completion of a feed stroke of operation pawl 32;ho lds flipper 36 rocked in a clockwise direction. During the final. retractive move ment of the parts above describedlug 33moves forward slightly and is caused to engage the rearward cam edge of a toothof the ratchet wheel 34. tobe cammed upward- 1y thereby. and above the pointed nose of the cam edge 36 of flipper 36. Thus lug 33will immediately release flipper 36, to counterclockwise'operation by its spring 37 and cam edge 36' acting on lug 33 restores the feed pawl 32 upwardly to normal position and outof-cooperative relation with respect to the ratchet pawl 34, whereby the platen is now again free for manual operation in either ect on...

. h leIherqhasbeen. shown and described a preferredv en 1bod imentof; the. present invention it Will be obvious that changes in form; and; details of the device may be made by those-skilledin the art,;and it is, therefore, contemplated'to cover; by the appended claims .anysuch modifications as fall within the true spirit and scope of the in-..

vention atI a m is;

l. In a listing calculating machine or the, like the combination comprising a rotatable platen, means for maintaining a paper-strip in contact therewith, a ratchet wheel carried by said, platen, an indexing pawl 00-.

reciprocatory means for releasing the indexing pawl from said engagement with the controlmember after thecompletion of-said advancing movement, and whereinifollowing said;release the said; control member will actto automatically displace the indexing pawl free of engagement with the ratchet wheel, whereby to normally permit rotation of the platen.in either direction.

2. In a, listing calculating machine or the like the combination comprising, a rotatable platen, means for maintaining a paper strip in contact therewith, a ratchet wheel carried by said platen, an indexing pawl adapted to maintain engagement therewith throughout an advancing operation to positively complete an index movement of the ,platen, a spring biased control member having a holding surface adapted for normally maintaining the index awlfree of cooperation with the teeth; of, said ratchet wheel, and means for effecting a reciprocatoryoperation ofsaidindexing pawl for advancing said ratchet wheel, and wherein the indexing pawl upon a forward movement of the indexing stroke is released from the saidaholding surface into engagement with the teeth of said ratchet wheel, and wherein upon a return stroke thereof for advancing the ratchet wheel saidindex pawl engages a forward edge of said holding surface and will act to move the control member to a position of stored potential energy, and where,- in following said advancing operation the index pawl is moved by the reciprocating means to be released thereby from the said'forward edge, and wherein the said control member willthereupon automatically restore-the-indexing pawl-'free of said ratchet Wheel.

' 3. In a listing calculating machine or the like the combination com prisingua rotatable platen, a ratchet wheel for rotating said platen, an indexing pawl adapted for reciprocatory operation and cooperable with said ratchet wheel for advancing the platen, an operating member normally holding the indexing pawl free of said ratchet wheel, and having a cam surface extending from a point outside the peripheral diameter of said ratchet wheel and terminating in a forward operating edge at a point intermediate of the root diameter of the ratchet wheel teeth, and means for effecting stored energy in said member, and wherein during a'reciprocating operation the indexing pawl is released into engagement with the teeth of said ratchet wheel, and into a cooperative relation with the said forward edge, and will thereafter during the indexing operation of the ratchet wheel effect a displacement of the operating member to an active position of stored energy, and wherein a continued movement of the indexing pawl thereafter releases the said energized operating member for camming said indexing pawl out of engagement with the teeth of said ratchet wheel.

4. In a listing calculating machine or the like the combination having a rotatable platen, means for maintaining a paper strip in contact with said platen, a ratchet wheel carried by said platen, means for effecting a positive advancement of said platen for a full in ement of movement including an indexing pawl having uniform engagement with said ratchet wheel throughout an indexing stroke of its movement, means for reciprocating said indexing pawl, said means being adapted to normally maintain said pawl in a position intermediate of the indexing stroke of movement, and a control means adapted in such intermediate position of said pawl for holding said pawl free of engagement with the said ratchet wheel, whereby to permit normallv a rotation of said platen selectively in either direction.

5. The invention according to claim 4 and wherein the said control means include a spring biased member having a cam edge extending from a point beyond the peripheral diameter of the ratchet wheel and terminating in a forward control edge at an opposite end thereof at a point intermediate of the root diameter of the teeth of said ratchet wheel, and wherein the indexing pawl during an indexing operation of the ratchet wheel engages said forward edge and will displace the spring biased member against the tension of its spring, and wherein the reciprocating means is adapted for thereafter returning the indexing pawl from its extreme advance position of index movement to the said normal intermediate position thereof, and wherein during said return movement the indexing pawl is cammed partially along a tooth of the ratchet Wheel to release the indexing pawl from the said forward control edge and to cause thereby an automatic spring operation of said control means, whereby the said cam edge thereupon restores the indexing pawl out of cooperation with the teeth of the ratchet wheel.

6. In a listing calculating machine or the like the combination of a rotatable platen, means for maintaining a paper strip in contact with said platen, a ratchet wheel carried by said platen, means for effecting a full stroke of positive advancement to said platen including an indexing pawl adapted for maintaining uniform engagement with an active tooth of the ratchet throughout the advancing operation, means engageable with successive teeth of said ratchet and adapted for locating the ratchet yieldably in adjusted positions, operating means for effecting reciprocatory movements of the indexing pawl, and normally ineffective latching means for said locating means, said latching means being adapted for operation by said reciprocating means in unison with operations of the indexing pawl, and wherein said latching means upon a completion of the platen advancing stroke movement of the indexing pawl is brought into locked engagement with the said locating means to thus lock the ratchet wheel against a farther rotation, and thereby effect a positive over-rotation check of the platen feed.

7. The invention according to claim 6 and wherein the said reciprocating means will thereafter impart a retrograde movement to the indexing pawl, whereby to return said pawl from the full stroke platen advance position back to the normal start position of said pawl and to concurrently therewith effect disengagement of said latching means from the said locating means, whereby the ratchet wheel is freed for any subsequent rotation as effected independently of the said platen advancing means.

8. In an apparatus of the character described the combination having a rotatable paper platen, a ratchet wheel for effecting feeding operations thereof, an indexing pawl engaging the ratchet wheel for a full indexing stroke of movement, a spring biased member adapted in normal position for holding said indexing pawl free of engagement with the ratchet wheel whereby to permit a manual rotation of the platen in either direction, resilient locator means for maintaining the platen in any adjusted position, a latch pawl cooperable with said locator means and normally inactive thereof, and means for concurrently effecting a reciprocatory operation of the indexing pawl and of the said latch pawl, and wherein the indexing pawl upon movement in one direction is released from the said holding member to effect engagement with an advanced tooth of said ratchet wheel and to also condition said indexing pawl to an effective position relative to the said holding member whereby in a return from said movement the indexing pawl effects both an advancing operation of the ratchet wheel and a displacement of the said holding member to an active position of potential energy, and wherein the reciprocating means in effecting terminal movement of the ratchet wheel effects engagement of the said latch pawl with the said locator means and will thereby provide for a positive over-rotation check of the feeding operation.

9. The invention according to claim 8 and including operating means for effecting a subsequent partial stroke movement of the reciprocating means, whereby to efiect a release of the latch pawl from the said platen locator means and to concurrently therewith release the said indexing pawl from the holding member, and wherein said holding member will thereupon act to restore the said indexing pawl free of engagement with the ratchet wheel.

10. In a machine of the character described having a rotatable platen, a ratchet carried by said platen, and an indexing pawl for advancing said ratchet, the combination of means responsive to an operation of said machine for reciprocating said pawl, said means normally holding said pawl at a position intermediate of an extremity of its travel, and a control member cooperable with the pawl in said intermediate position for normally maintaining said pawl free of engagement with the teeth of said ratchet, whereby normally to permit a manual rotation of said platen in either direction, and wherein during reciprocating operation the indexing pawl is released from said control member to engage an advanced tooth of the ratchet, and to thereafter effect positive advancement of the ratchet a full increment of selected movement, and wherein during a completion of said movement the indexing pawl will act to displace the said control member to an active condition of stored energy, and wherein the reciprocating means thereafter effects a restoring movement of the indexing pawl to its intermedlate position whereby to release the said pawl from said control member and thereby cause operation thereof, and wherein during said operation the control member automatically restores the indexing pawl to normal position and free of the teeth of said ratchet.

11. In a machine of the character described having a rotatable platen, a ratchet carried by said platen and a feed pawl for advancing said ratchet, the combination 7, of means responsive to an operation of said machine for reciprocating'said pawl, said means being adapted for holding said pawl normally at a position intermediate of an indexing movement, a control member adapted with the feed pawl in said intermediate position for holding said pawl free of engagement with theteeth of said ratchet, so that the platen is normally free for rotation in either direction, a normally resilient locator, for engaging successive teeth of the ratchet to hold the platen in adjusted positions, and a springlatch operable with the feed pawl, said latch in said intermediate position of the feed pawl being held free of engagement with the said locator, and wherein near the end of a platen advancing. movement said'latch is moved'into yieldable engagement with the said locator, andwherein at substantially a terminal advancing movement of the feed pawl said'latch snaps into 8e, engagement with the said locator to positively lock the said locator and'thusalso rotation ofsaid ratchet against an overfeed movement, and wherein a continued operation of the reciprocating means thereafter restores the said feed'pawl to.its intermediate position, and will concurrently therewith release the said latch from the said' locator, andwherein during the said restoring operation the said control member acts to automatically restore the feed pawl free of engagement with the ratchet, whereby following such indexing operation the platen is again free for rotation in either direction.

References Cited in the file of this patent UNITED STATES PATENTS 2,797,791 Kuhne July 2, 1957

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