US3026011A - Variable speed paper feeding drive - Google Patents

Description

4 Sheets-Sheet 1 FIG. I

\ INVENTOR. ALBERT M. GRASS ATTO R N EYS A. M. GRASS March 20, 1962 Filed March 22, 1960 BY KERWAY, JENNEY. WITTER an HIlDREIH March 20, 1962 GRASS 3,026,011

VARIABLE SPEED PAPER FEEDING DRIVE Filed March 22, 1960 4 Sheets-Sheet 2 INVENTOR. ALBERT M. GRASS BY KENWAY, JENNEY, WITI'ER & HHDRETH ATTOR NEYS March 20, 1962 A. M. GRASS 3,026,011

VARIABLE SPEED PAPER FEEDING DRIVE Filed March 22, 1960 4 Sheets-Sheet 3 FIG. 4 I00. 28

MMfSEC 34 .25 MM/SEC. so. ham/550 x 5s 5s 25 MM/SEC s MM/SEC 5o 50 5e 5e 50 50 IO. MM/sEc\ xv/1.0 MM/SEC.

2.s MM ISEC.

INVENTOR. ALBERT M. GRASS BY IENWAY. TENNEY. WITTFR z Hnnnrm ATTORNEYS March 20, 1962 A. M. GRASS 3,026,011

. VARIABLE SPEED PAPER FEEDING DRIVE Filed Mafch 22, 1960 4 Sheets-Sheet 4 FIG. 6

FIG. 7

INVENTOR. ALBERT M. GRASS Y M,) w7, JW

ATTORNEYS 3,026,611 VARIABLE SPEED PAPER FEEDING DRIVE Albert M. Grass, 101 Old Colony Ave, Quincy, Mass. Filed Mar. 22, 1960, Scr. No. 18,464 15 Claims. (til. 22617S) This invention relates to a novel and improved variable speed paper feeding mechanism for recording instruments. This application is a continuation-in-part of my copendmg application Serial No. 799,992, filed March 17, 1959 now abandoned. In recording instruments wherein a continuous recordmg is made on a moving chart or paper, it is often desirable or necessary to change the speed of advance of the paper or chart to vary the presentation of the record. An exernplary prior attempt to provide a satisfactory variable speed paper drive involves the use of a gear train having a plurality of driven gears continuously rotating at different speeds with the entire train being mounted for indexing as a unit to connect a selected one of the driven gears to a drive mechanism for advancing the paper and thus to advance the paper at a selected speed. Such a device requires that the gear train be disconnected from the paper advance mechanism and/or the means driving the gear train in order for the gear train to be indexed, as a unit, to a different position corresponding to the desired speed. As is Well known, whenever gears, splines and the like are disengaged, particularly if one of the gears is moving, attempted reengagement of the gears is often impeded or prevented by interference between the teeth of the gears. Further, the meshing of stationary gear with a moving gear may result in damage to the gears, thus often requiring that the drive motor of a device such as described be completely stopped during a speed change operation. This attendant loss of time, and thus a portion of a record during a recording, is undesirable.

Accordingly, it is the primary object of this invention to provide a novel and improved variable speed paper feeding device which permits changes in the speed of paper advance without necessitating the deenergizing of the drive motor for the device and without disconnecting the speed change mechanism from the drive motor.

It is a further object of this invention to provide a novel and improved variable speed paper feeding device of the type described having novel and improved means for disengaging the drive motor from the paper during a change in speed of paper advance.

An appreciation of the advantages of the invention as well as a detailed understanding of the structure of a specific embodiment thereof may be had from the following description taken in connection with the accompanving drawings, in which:

FIG. 1 is a cross sectional view with certain parts removed in the interest of clarity, of a recording instrument incorporating a variable speed paper drive constructed in accordance with this invention;

FIG. 2 is a fragmentary cross sectional view substantially along the line 2-2 of FIG. 1;

FIG. 3 is a fragmentary cross sectional view substantially along the line 3-3 of FIG. 1;

FIG. 4 is a fragmentary cross sectional view substantially along the line 4-4 of FIG. 1;

FIG. 5 is a fragmentary cross sectional view substantially along the line 55 of FIG. 1;

FIG. 6 is a fragmentary cross sectional view similar to FIG. 1 illustrating an alternative embodiment of the means for disengaging the drive motor and paper during a change in speed of paper advance; and

FIG. 7 is a fragmentary cross sectional view substantially along the lines 77 of FIG. 6.

With reference to the drawings, and particularly FIG.

1, there is shown a recording instrument including a casing 10 generally comprising side walls 11 and 12 and a bottom wall 13. The side walls support a top plate or wall 14, along which it is desired to advance a paper or chart 15. In the interest of brevity and as it is not necessary for a complete understanding of the invention, the mechanism for recording a measurement or the like on the paper has not been shown. A bracket 16 secured to the bottom wall 13 supports a pair of spaced apart parallel mounting plates 18 and 20. The front plate 18 supports an electric drive motor 22 having a drive pinion 24 drivingly engaging an idler gear 26 rotatably supported by the plate 18. A gear box 28 is disposed between the plates 18, 2t) and is mounted for movement with a central shaft 30 rotatably mounted in bushings supported by the plates 18 and 20. The gear box comprises a pair of circular plates 32, 34 secured to the shaft 30 on opposite sides of an enlarged portion of the shaft which spaces the plates 32, 34 in parallel relationship. A drive roller shaft 36 is supported by ball hearings on the plates 32, 34 with the shaft 36 extending in parallel radially spaced relation to the shaft 30. The roller shaft 36 carries a driven gear 38 disposed externally of the gear box 28 and engageable with an idler gear 40 rotatably carried by the plate 34. The idler gear 40 is engageable with a gear 42 coaxially received over the shaft 30 and rotatably mounted thereon by a bushing. A gear 44 is mounted coaxially of the gear 42 for rotation therewith relative to the shaft 30 and is engageable by the idler gear 26, previously described, whereby the motor drive pinion 24 will, upon energizing of the motor, rotate the drive roller shaft 35.

The drive roller shaft 36 mounts a drive roller 46, externally of the gear box 28, for rotation with the shaft 36. The roller is partially received in an aperture in the top plate 14 wherein it is drivingly engageable with the underside of the paper 15. The periphery of the roller is preferably provided with a surface conducive to good driving engagement with the paper, such as by knurling the roller, or by other suitable means. The paper is normally held down in firm engagement with the drive roller 46 by pressure roll means 48, to be described in detail hereinafter.

As most clearly shown in FIG. 3, the gear box 28 carries a plurality of additional drive rollers 46' similar to the drive roller 46 just described, with the rollers 46 and 46 being circularly arranged concentrically about the axis of the shaft 30. With particular reference to FIG. 4, each of the rollers 46' is mounted on a shaft 50 rotata-bly supported in hearings on the plates 32, 34 and extending between the plates. Each of the shafts 50 carries a pair of gears 52, 54 fixed thereto and disposed between the plates 32, 34, with the exception of the shaft next adjacent the shaft 36 and to the right thereof, as viewed in FIG. 4. A plurality of idler gear shafts 56 are rotatably supported on hearings on the plates 32, 34, and each of the idler shafts carries a pair of gears 58, 60 fixed thereto and disposed between the plates 32, 34. The idler gear shafts are circularly arranged concentrically about the shaft 30, with each shaft 56 being disposed generally between a pair of next adjacent drive roller shafts St The drive roller shaft 36 has a gear 62 fixed thereon which is engageable with the idler gear 58 next adjacent thereto in a counterclockwise direction, as viewed in FIG. 4; and the associated idler gear 60 is engaged with the gear 52 on the drive roller shaft 50 next adjacent thereto in a counterclockwise direction, as viewed in FIG. 4. The other gear 54 of this drive roller shaft is engaged with the idler gear 58 of the next adjacent idler gear and so on in a counterclockwise direction until the last idler gear 60 is reached, this last idler gear 60 being meshed with a single gear 64 on the last drive roll shaft 59 in the train. In the specific embodiment shown, the ratios between the various pairs of meshed gears has been selected to provide a speed reduction through the train of from 100 mm. per second peripheral speed at the drive roller 46 to a peripheral speed of .25 mm. per second at the last drive roller in the train. It is, of course, to be understood that these values are purely by way of example and that the speed of the various rollers could be selected and varied from one to the other as desired for any particular use merely by selecting the proper gear ratios in the train.

Turning back to FIG. 1, it can be seen that the shaft 30 is axially bored and slidably receives and supports an indexing shaft 66 extending out of the right end of the shaft 30 and at its free outer end slidably and rotatably supported by a bushing on the side wall 11 of the casing 10. Fixed to the shaft 66 adjacent the right end of the shaft 30 is a male coupling member 68 having keys 70 extending longitudinally of the shaft 30 and drivingly engaged in slots 72 in the adjacent end of the shaft 30. The ends of the keys 76 are preferably spaced from the inner end of the slots 72 to permit leftward movement of the shaft 66 relative to the shaft 30, as viewed in FIG. 1. As will be apparent, rotation of the shaft 66 will result in rotation of the ear box 28 about the axis of the shaft 36 to position a different one of the drive rollers in registry with the underside of the paper so as to vary the speed of advance of the paper. A knob or handle 69 is fixed to the rightward end of the shaft 66 which projects outwardly of the casing 10, and the knob is preferably provided with suitable indicia to indicate the various paper speeds obtainable.

It should be noted that during rotation of the gear box no portion of the drive gear train is disconnected from another portion thereof or from the drive motor 22. In this connection, during rotation of the shaft 66, and thus the gear box 28, the idler gear 46 carried by the gear box will be revolved about the axis of the gear 42 engaged therewith in planetary fashion.

The shaft 66 is biased in a rightward direction, as viewed in FIG. 1, by a compression spring '74 engaged between a pin on the connector 68 and the end of a split collar 76 clampingly engaging a bushing 78 on the shaft 30. The collar 76 and bushing 78 form a part of an indexing cam assembly most clearly shown in FIG. 5. The bushing 78 is slotted at one end to provide a plurality of cantilever fingers 81} which clampingly engage the shaft under the influence of the collar 76. As shown in FIG. 1, the bushing mounts an indexing cam 82 for movement therewith coaxially of the shaft 39. As shown in FIG. 5, the cam 82 has a generally scalloped periphery including a series of promontories and valleys, with the number of valleys corresponding to the number of drive rollers on the gear box 23. An arm 84 is pivotally mounted at one end on the front plate 18 and carries intermediate its ends a cam roller or follower 86 engageable in the valleys of the cam 82 and a spring 88 urges the cam follower into cam engagement. As will be apparent from FIGS. 1 and 5, the cam 82 is angularly positioned relative to the shaft 36 so that when the cam roller 86 is engaged in one of the valleys of the cam, one of the drive rollers of the gear box 28 will be positioned for driving engagement with the paper.

With reference to FIGS. 1 and 2, the pressure roll mechanism will now be described. The leftward end of the shaft 66, as viewed in FIG. 1, projects through the rear plate 2.0 and mounts a cam 96 for movement therewith. The cam 96 is circular in plan and has a frusto-conical peripheral surface 92 arranged coaxially of the shaft 66 and tapering toward the leftward end of the shaft 66. A cam follower 94- is slidably received in a recess in the plate 26 for movement generally radially of the shaft 66. The follower 94 includes a roller 96 engaging the conical surface of the cam 90 so that in response to leftward movement of the shaft 66 the cam M! will raise the cam follower 94. The follower 94 is provided with a recess in its upper end in which is received the reduced diameter lower end of a plunger Q8 extending through an opening in the top plate 14 and having a lip or flange at its upper end normally resting on the top wall 14. An arm 166, pivoted at one end, is supported on the casing it) and extends generally parallel to the upper side of the top plate 14. A screw 162 threadably extends through the arm Mid and is engageable with the upper end of the plunger 98. The arm 1% rotatably mounts a pressure roll 164 having an axis extending parallel to the axis of the shaft 36). The roll 164 is engageable with the upper surface of the paper 15 to firmly engage the paper with a drive roller underneath the paper, and a spring 106 urges the arm 1% and thus the pressure roll 164 toward the paper.

It should be noted that the cam 99 also serves as a locking plate for the shafts 66 and 36. In this connection, it may be seen in FIGS. 1 and 2 that the cam M) has a plurality of openings 108 circularly arranged concentrically of the shaft 66. A pin 110 on the plate 20 is engageable in an opening 108 registering therewith to lock the shafts 66 and 30 against angular movement when the shaft is in its rightward position as viewed in FIG. 1. The openings 168 correspond in number to the number of drive rollers on the gear box 28, and the cam is angularly positioned on the shaft 66 so that with the cam roller 86 of the shaft indexing assembly engaged in a valley of the indexing cam 82 the pin 110 will be aligned with one of the openings 108.

In the operation of the device just described, when it is desired to change the speed of paper advance, the shaft 66 is pressed inwardly of the casing 10 to move the cam 90 to the left, as viewed in FIG. 1, to disconnect the cam from the pin 110 and free the shafts 30 and 66 for rotation. At the same time, the cam will raise the cam follower 9 and thus the plunger 93, to pivot the arm 16%) in a counterclockwise direction as viewed in FIG. 2 to lift the pressure roll 1G4 and effectively disengage the paper and drive roller. The shafts 66 and 36 may then be rotated to the desired angular position corresponding to the paper speed desired, whereupon the indexing cam and roller will hold the shaft 30 in its new angular position. Upon release of the shaft 66, the spring 74 will return the shaft to its rightward position, whereupon the pin 116 will be engaged in the proper opening 108 of the cam 90 to again lock the shafts 66 and 30 against rotation.

As noted before, during the speed change operation, none of the drive gearing of the device is disconnected so as to eliminate any necessity for reengaging relatively moving elements. Accordingly, if desired, the paper speed may be changed without deenergizing the motor 22. This feature permits adjustment of paper speed without any significant loss of record in a continuous recording operation. Where a low speed paper advance is contemplated, say on the order of 1 mm./sec., it will be apparent that if the drive roller had to be disengaged from the gear train in order to adjust the paper advance, and if the mating parts on the drive roller and gear train were out of alignment when reengagement was attempted, it might take several minutes before the matingbecame realigned so at to permit reengagement thereof and continuation of the recording. The variable speed drive of this invention obviously eliminates any such undesirable delay. Further, it should be noted that the automatic disengagement of the paper and drive roller immediately prior to adjustment of the gear box assures that during adjustment of the gear box the paper will not become jammed between the pressure roll and drive rollers or be forced in a direction opposite the normal direction of paper advance. A variable speed paper drive constructed in accordance with this invention will thus provide the accurate and reliable service necessary for recording instruments While at the same time is relatively simple and economical and is of rugged construction to provide an extended trouble-free service life.

With reference to FIGS. 6 and 7, there is shown an alternative means for disengaging the pressure roll for the paper during a speed change adjustment of the gear box and also for releasably holding the gear box in a desired angular position. The mechanism of FIGS. 6 and 7 performs the combined functions of the indexing earn assembly of FIG. 5 and the pressure roll disengaging and gear box locking mechanism of FIG. 2. As will be seen from the following, the mechanism of FIGS. 6 and 7 accomplishes the disengagement of the pressure roll in response to initial rotation of the indexing shaft 66 and eliminates the need for moving the shaft axially of itself prior to rotating the shaft to index the gear box and effect a change in the speed of paper advance. In describing this aspect of the invention like reference numerals will be used in connection with parts which are similar to the parts previously described in connection with the device of FIGS. 1-5.

A cam 120 is fixed on the end of the indexing shaft 66 projecting outwardly of the end of the shaft 30 and beyond the mounting plate 20. As shown in FIG. 7, the periphery of the cam is provided with a plurality of notches or recesses 122 and promontories 124. The recesses 122 correspond in number and angular orientation to the drive rollers. A cam follower 126 is mounted on the frame of the device for vertical movement radially of the cam. The earn follower includes a roller 128 which is engageable with the periphery of the cam 120. The follower 126 also includes a spring biased plunger 13f extending upwardly from the upper end of the follower. The upper end of the plunger 130 engages the lower end of the screw 102 carried by the pivoted arm 160* which mounts the pressure roll 104. It will be apparent that as the index shaft 30 is rotated from the position of FIG. 7, the cam follower 126 will ride out of a recess 122- and up onto a promontory 124 to disengage the pressure roll 1634 from any paper between the pressure roll and an underlying drive roller. Further rotation of the cam 12% by the index shaft 66 will cause the cam follower 126 to drop back into a recess 122 and effect lowering of the pressure roll into paper engagement under the influence of the spring 106 biasing the arm 100.

A locking plate or cam 132 is fixed on the end of the shaft 30 and is disposed between the cam 126 and mounting plate 20. As most clearly shown in FIG. 7, the locking plate is generally circular and is provided with a plurality of angularly spaced apart notches or recesses 134 in its periphery. The recesses 134 correspond in number and angular orientation to that of the drive rollers of the device. The cam follower 126, as shown in FIG. 6, has a depending projection 136 which is receivable in the notches 134 of the locking plate. The projection 136 is centered relative to the roller 128 in the sense that the longitudinal center line of the projection passes through the axis of the roller and extends in the direction of movement of the follower. When the projection 134 is so received in a locking plate notch, the gear box 28 will be positioned angularly about the shaft 39 so that one of the drive rollers is in registry with the pressure roll 104. In order to provide the indexing drive for the gear box, the locking plate 132 is provided with an elongated slot 138 which is generally centered relative to one of the notches 134. The cam plate 120 mounts a pin 140 which is centered relative to one of the recesses 122 in the cam and which is receivable in the slot 138 in the locking plate. Inasmuch as the pin 140 and slot 138 are both centered relative to one of the notches 122 and 134 in the cam and locking plates respectively, it will be seen that when the cam follower is engaged in one of the notches of the cam plate the pin 140 will be centered in the slot 138. As will be apparent, the pin and slot connection between the cam and locking plates provides a lost motion driving connection between the indexing shaft 66 and gear box 28.

When it is desired to index the gear box to change the speed of paper advance, the index shaft 66 is rotated by the hand wheel 69. Initial rotation of the shaft 66 will cause rotation of the cam 12%. However, because of the lost motion connection between the cam and locking plates, the gear box will not be moved until the cam has been rotated sufficient for the pin to engage one end of the slot 138 in the locking plate. The slot 138 is sufficiently long so that prior to engagement of the pin 146 with an end of the slot 138, the pressure roll 104 will have been disengaged from the paper. Further, rotation of the cam 120 in the same direction will cause rotation of the locking plate 132. While the raising of the follower 126 will cause the projection 136 to be moved in a direction outwardly of a notch 134 in the locking plate, it is preferred that the sides of the notches 134 be sloped outwardly of the notches so that the sides of the notches will tend to cam the projection upwardly and out of the notches. After the follower has been raised sufiiciently the projection 136 will ride onto the periphery of the locking plate between the notches and prevent downward movement of the follower. After suflicient rotation of the locking plate, the projection 136 will be in registry with another notch 134 and will be urged into the notch by the spring 166 biasing the arm 1110 so as to lock the gear box in a new position. As the projection moves into registry with a notch, the cam and locking plates will be angularly offset relative to each other because of the lost motion drive therebetween. In this connection, the length of the slot 138 in the locking plate is selected to provide that the total angular movement of the pin 140 from one end of the slot to the other end is less than the angular spacing of the crests of next adjacent promontories on the cam plate. Accordingly, when the projection 136 is moved into registry with a notch, the roller 128 will be angularly offset from a crest of a promontory on the cam 121) and in a direction opposite the direction of rotation of the cam plate. Therefore, as the projection 136 is moved into a notch on the locking plate by the force of the spring 166, the roller 128 which is also biased by the spring 166, will tend to be moved into the cam plate recess 122 with which it is in partial registry. As the roller moves into the recess it will cam the plate 120 in a direction opposite the direction it had been turned and the pin 14% will again be centered in the slot 138. Thus it can be seen that there has been provided means for sequentially disengaging the pressure roll from the paper, angularly indexing the gear box, and re-engaging the pressure roll and paper all through operation of the index shaft 66 with the disengagement of the pressure roll being in response to initial operation of the shaft. While the operation has been described with respect to rotating the shaft 66 and gear box in one direction, it will be apparent that the shaft 66 may be rotated in either of both directions of rotation with the same result.

Inasmuch as many changes could be made in the above construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the language in the following claims is intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

I claim as my invention:

1. In a variable speed mechanism for advancing record paper and the like, a gear box fixed against axial movement and mounted for rotation about an axis and supportin a gear train, means to rotate said gear box, releasable means normally holding said gear box against rotation, a plurality of paper engageable drive rollers carried by the gear box and respectively connected to different portions of said gear train, a gear mounted for rotation coaxially of the axis of the gear box and relative to the gear box and said means to rotate the gear box, means to drive said gear including a drive gear engaged therewith, and means drivingly connecting the rst mentioned gear to said gear train including an idler gear rotatably mounted on said gear box and engaged with the first mentioned gear so that upon rotation of said gear box about its axis said idler gear will be revolved about the axis of said first gear to permit angular adjustment of the gear box about its axis without disconnecting the drive rollers from said first gear.

2. In a variable speed mechanism for advancing record paper and the like, a rotatable gear box supporting a gear train, a plurality of paper engageable drive rollers supported by the gear train, a rotatable indexing shaft disposed coaxially of the gear box and connected for rotation therewith, releasable means holding the shaft against rotation, a driven gear rotatably supported for rotation coaxially of the shaft and relative to the shaft and gear box, an idler gear mounted on the gear box for rotation about an axis extending in parallel spaced relation to the axis of the first mentioned gear, the idler gear being engaged with the first gear and being drivingly connected to the gear train, means to drive the first gear, and means to selectively rotate said shaft whereby said idler gear will be revolved about the axis of the intermediate gear in planet gear fashion as the gear box is rotated with the shaft.

3. In a variable speed mechanism for advancing record paper and the like, a rotatably mounted gear box supporting a gear train and carrying a plurality of paper engageable drive rollers connected respectively to different portions of the gear train, said gear box being rotatable through a plurality of adjusted positions in each of which positions a selected one of said rollers is in paper engageable position, a pressure rol-l supported for move ment toward and away from the axis of said one of the rollers for firmly engaging a record paper with said one of the rollers, and means operable to move said pressure roll away from said one of the drive rollers and sequendaily to ro-tatably index said gear box including a movable shaft, said means being operable to move said pressure roll away from said one of the drive rollers in response to initial movement of said shaft.

4. In a variable speed mechanism for advancing record paper and the like, a rotatably mounted gear box supporting a gear train and carrying a plurality of paper engageable drive rollers connected respectively to different portions of the gear train, said gear box being rotatable through a plurality of adjusted positions in each of which positions a selected one of said rollers is in paper engageable position, a pressure roll supported for movement toward and away from the axis of said one of the rollers for firmly engaging a record paper with said one of the rollers, means for rotating the gear box including an axially movable and rotatable shaft, and means connected to the pressure roll and responsive to axial movement of the shaft to move said pressure roll away from said one of the drive rollers.

5. In a variable speed mechanism for advancing record paper and the like, a rotatably mounted gear box supporting a gear train and carrying a plurality of paper engageable drive rollers arranged about the axis of the gear box and connected respectively to different portions of the gear train, said gear box being rotatable through a plurality of adjusted positions in each of which positions one of said rollers is in paper engageable position, a pressure roll engageable with the opposite side of paper engaged by said one of said rollers, means mounting the pressure roll for movement toward and away from said one of said rollers, means urging the pressure roll toward said one of said rollers, and means to sequentially move the pressure roll away from said selected one of said rollers and rotate said gear box including a rotatable and axially movable shaft connected to the gear box for rotation therewith and for axial movement relative thereto, a cam on the shaft, and a cam follower operatively connecting the cam with the pressure roll.

6. In a variable speed mechanism for advancing record paper and the like, a rotatable gear box supporting a gear train and carrying a plurality of paper engageable drive rollers respectively connected to diiferent portions of the gear train, a shaft mounted for rotation and for axial movement, the shaft being connected to the gear box for axial movement relative thereto and for rotation therewith through a plurality of adjusted positions of the gear box in each of which positions one of said drive rollers is in paper engageable position, a paper engageable pressure roll, a pivoted arm mounting the pressure roll for movement toward and away from said selected one of said drive rollers, a spring urging the pressure roll toward said one of said drive rollers, a cam mounted on said shaft for axial movement therewith and having a frusto-conical cam surface arranged coaxially of said shaft, a cam follower engageable with said cam surface and connected to said arm so that on movement of the shaft axially in one direction the pressure roll will be moved away from said selected one of said rollers.

7. In a variable speed mechanism for advancing record paper and the like, a rotatable gear box supporting a gear train and carrying a plurality of paper engageable drive rollers circularly arranged concentrically of the axis of the gear box and connected respectively to different portions of the gear train, said gear box being rotatable through a plurality of adjusted positions in each of which positions one of said rollers is in paper engageable position, an indexing cam mounted for rotation coaxially of and with the gear box and having a plurality of separate surfaces on its periphery respectively corresponding in angular relationship about the gear box axis with said drive rollers, a spring biased cam follower engageable with said surfaces on the cam for resiliently holding the gear box in each of said adjusted positions, disconnectable means providing positive holding of the gear box in each of said adjusted positions, and means to rotate the gear box including a rotatable and axially movable shaft rotatively connected to the gear box and connected to a portion of said disconnectable means to disconnect the same in response to axial movement of the shaft.

8. In a variable speed mechanism for advancing record paper and the like, a rotatable gear box supporting a gear train and carrying a plurality of paper engageable drive rollers circularly arranged concentrically about the gear box axis and respectively connected to different portions of the gear train, said gear box being rotatable through a plurality of adjusted positions in each of which positions one of the drive rollers is in paper engageable position, indexing cam means for resiliently holding the gear box in each of said positions, disconnectable means for providing positive holding of the gear box in each of said adjusted positions, a shaft for rotating the gear box, means connecting the shaft to the gear box for rotation therewith and for axial movement relative to the gear box, means urging the shaft axially in one direction, said disconnectable means being in part connected to said shaft and being disconnectable in response to axial movement of the shaft in the direction opposite said one direction.

9. In a variable speed mechanism for advancing record paper and the like, a rotatably mounted gear box supporting a gear train and carrying a plurality of paper engageable drive rollers connected respectively to different portions of the gear train, said gear box being adjustable through a plurality of rotated positions in each of which positions one of said rollers is in paper engageable position, means externally of the gear box to drive said gear train, a rotatable shaft extending coaxially of the gear box and movable axially relative to the gear box, means providing a driving connection between the shaft and gear box for rotation of the gear box by the shaft while permitting axial movement of the shaft relative to the gear box, means urging the shaft axially in one direction, a pressure roll mounted for movement toward and away from said one of said rollers, means for moving the pressure roll away from said one of said rollers in response to movement of said shaft in the direction opposite said one direction including a cam on said shaft, the cam being provided with a plurality of recesses arranged about the axis of the shaft and corresponding respectively to said adjusted positions of the gear box, and fixed shoulder means engageable in said recesses to positively hold the gear box in each of said adjusted positions, said shoulder means being disengagea-ble for each recess in the cam upon movement of the cam in the direction opposite said one direction of shaft movement.

10. In a variable speed mechanism for advancing record paper and the like, a gear box mounted for rotation about an axis and supporting a gear train, a plurality of circularly arranged paper engageable drive rollers carried by the gear box concentrically of the gear box axis and connected respectively to different portions of the gear train, the gear box being rotatable through a plurality of adjusted positions in each of which positions one of said drive rollers is in paper engageable position, a gear mounted for rotation coaxially of the gear box, means to drive said gear, means drivingly connecting said gear to the gear train including an idler gear rotatably carried by the gear box and meshed with the first gear for rotation thereby about an axis extending in spaced parallel relation to the axis of said first gear, a pressure roll mounted for movement toward and away from said one of said rollers for firmly engaging a record paper with said one of said drive rollers, a shaft connected to the gear box for rotation thereof and for axial movement relative thereto, means connected to the pressure roll and responsive to axial movement of said shaft to move the pressure roll away from said one of said drive rollers, and releasable means normally preventing rotation of the gear box by said shaft, a portion of said releasable means being connected to said shaft to release the gear box for rotation in response to axial movement of the shaft.

11. In a variable speed mechanism for advancing record paper and the like, a gear box mounted for rotation about an axis and supporting a gear train, a plurality of circularly arranged paper engageable drive rollers carried by the gear box concentrically of the gear box axis and connected respectively to different portions of the gear train, the gear box being rotatable through a plurality of adjusted positions in each of which positions one of said drive rollers is in paper engageable position, a gear mounted for rotation coaxially of the gear box, means to drive said gear, means drivingly connecting said gear to the gear train including an idler gear rotatably carried by the gear box and meshed with the first gear for rotation thereby about an axis extending in spaced parallel relation to the axis of said first gear, a pressure roll mounted for movement toward and away from said one of said rollers for firmly engaging a record paper with said one of said drive rollers, a shaft connected to the gear box for rotation thereof and for axial movement relative thereto, a cam carried by said shaft for rotative and axial movement therewith, follower means connecting the cam and pressure roll to provide for movement of the pressure roll away from said one of said drive rollers in response to axial movement of the shaft in one direction, a spring urging the shaft in a direction opposite said one direction, a plurality of recesses in said cam circularly arranged coaxially of the shaft and corresponding respectively to said adjusted positions of the gear box, and a fixed member engageable in said recesses to hold said shaft and cam against rotation in a position corresponding to a selected adjusted position of the gear box and being disengageable from the cam in response to axial movement of the shaft in said one direction.

12. In a variable speed mechanism for advancing record paper and the like, a rotatably mounted gear box supporting a gear train and carrying a plurality of paper engageable drive rollers arranged about the axis of the gear box and connected respectively to different portions of the gear train, said gear box being rotatable through a plurality of adjusted positions in each of which positions one of said rollers is in paper engageable position, a pressure roll engageable with the opposite side of paper engaged by said one of said rollers, means mounting the pressure roll for movement toward and away from said one of said rollers, means urging the pressure roll toward said one of said rollers, and means to sequentially move the pressure roll away from said selected one of said rollers and rotate said gear box including a rotatable shaft, said means being operable to initiate movement of the pressure roll away from said selected one of said rollers in response to initial rotation of said shaft.

13. In a variable speed mechanism for advancing record paper and the like, a rotatably mounted gear box supporting a gear train and carrying a plurality of paper engageable drive rollers arranged about the axis of the gear box and connected respectively to different portions of the gear train, said gear box being rotatable through a plurality of adjusted positions in each of which positions one of said rollers is in paper engageable position, a pressure roll engageable with the opposite side of paper engaged by said one of said rollers, means mounting the pressure roll for movement toward and away from said one of said rollers, means urging the pressure roll toward said one of said rollers, means to move said pressure roll away from said selected one of said rollers including a rotatable member, and a lost motion driving connection between said rotatable member and the gear box.

14. In a variable speed mechanism for advancing record paper and the like, a rotatably mounted gear box supporting a gear train and carrying a plurality of paper engageable drive rollers arranged about the axis of the gear box and connected respectively to different portions of the gear train, said gear box being rotatable through a plurality of adjusted positions in each of which positions one of said rollers is in paper engageable position, a pressure roll engageable with the opposite side of paper engaged by said one of said rollers, means mounting the pressure roll for movement toward and away from said one of said rollers, means urging the pressure roll toward said one of said rollers, means to move said pressure roll away from said selected one of said rollers including a rotatable cam and a movable cam follower, means releasably holding the gear box in selected angularly adjusted position including a locking member mounted for rotation with the gear box and having a plurality of recesses angularly spaced about the gear box axis and corresponding in number and angular spacing to that of said rollers, a member movable into and out of said recesses, and a lost motion driving connection between said cam and locking member.

15. In a variable speed mechanism for advancing record paper and the like, a gear box mounted for rotation about an axis and supporting a gear train, a plurality of circularly arranged paper engageable drive rollers carried by the gear box concentrically of the gear box axis and connected respectively to difierent portions of the gear train, the gear box being rotatable through a plurality of adjusted positions in each of which positions one of said drive rollers is in paper engageable position, a gear mounted for rotation coaxially of the gear box, means drivingly connecting said gear to the gear train including an idler gear rotatably carried by the gear box and meshed with the first gear for rotation thereby about an axis extending in spaced parallel relation to the axis of said first gear, a pressure roll mounted for movement toward and away from said one of said rollers for firmly engaging a record paper with said one of said drive rollers, a shaft extending coaxially of the gear box, said shaft being rotatable relative to the gear box, a cam mounted on said shaft for rotation therewith, said cam having a series of valleys and promontories arranged about the axis of said shaft, a follower engageable with said promontories and valleys and operatively connected to said pressure roll to move the same in response to rotation of the cam to move the follower out of one ofsaid valleys, said valleys corresponding in num- References Cited in the file of this patent UNITED STATES PATENTS 2,642,756 Cummings June 23, 1953 a ---r A l,

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