US3322316A - Line feed mechanism - Google Patents

Description

May 30, 1967 c. H. CLARK ETAL.

LINE FEED MECHANISM 3 Sheets-Sheet l Original Filed Oct. 25. 1962 INVEN'I'ORS C/.AYro/v h'. CLARK Do/vALo J rEFA/v/K A ORNEY5 May 30, 1967 LINE FEED MECHANISM Original Filed Oct. 25, 1962 3 Sheets-Sheet 2 INVENTORS CLAYTo/v H.` CLARK DONA/ 0 J. STEFAN/K A ORNEYS C. H. CLARK ETAL 3,322,316`

May 30, 1967 c. H. CLARK ETAL LINE FEED MECHANISM 5 Sheets-Sheet 5 Original F'iled Oct. 25. 1962 INVENTORS C1A rolv H Ik am'. [MMM By j MJ A ORNEYS 3,322,316 LINE FEED MECHANISM Clayton H. Clark, Mundelein, and Donald J. Stefaniir,

Berwyn, Ill., assignors to SCM Corporation, a corporation of New York Original application st. 2S, 1962, Ser. No. 233,109, now Patent No. 3,291,909, dated Dec. 13, 1966. Divided and this application May 2, 1966, Ser. No. 546,917

7 Claims. (Cl. 226-141) versatile and readily adapted for use with other datal processing page recorders su-ch as electric typewriters and conventional telegraph printers.

The improvements of this present invention involve the mechanical components to accomplish selectively variable record paper feed which will be referred to as line feed hereinafter. As compared withthe line feed mechanism described in co-pending application Ser. No. 184,820, filed April 3, 1962, now Patent No. 3,280,256, the line feed mechanism has been substantially improved and made more versatile by utilizing a motor driven power feed rather than a solenoid operated feed and by using a novel controllable line feed to enable variation in the number of lines the record is fed during each feed operation, the power required being proportional to the line feed desired.

Accordingly, a primary object of this invention resides in the provision of an improved line feed mechanism for use in data processing equipment such as page printers or telegraph typewriters and the like.

Still another object resides in the provision of an improved page printer with novel record medium line feed mechanism powered from a power shaft driven, rotatable start-stop cam assembly and a cam follower linkage operating a pawl and ratchet transmission to the record engaging feed components, having means to vary the magnitude of the actual stroke of the cam follower as imparted by the power driven cam assembly. In conjunction with the foregoing object, it is a further object to accomplish the start-stop line feed cycle by a solenoid which will enable associated equipment control circuitry to automatically accomplish a line feed cycle energization of the line feed solenoid for every carriage return operation of a page printer.

A still further object resides in a provision of a novel selectively variable record medium line feed mechanism for use in typing or printing mechanism. In connection with the preceding object, a further object resides in providing an improved line feed mechanism in which the power stroke is selectively variable.

Further novel features and other objects of this invention will become apparent from the following detailed description, discussion and the appended claims taken in conjunction with the accompanying drawings showing the subcomponent structures and units constituting the present invention, in which:

FIGURE 1 isla front perspective skeleton view illustrating the major mechanical components of a drum printer which incorporates the line feed mechanism of the Vpresent invention. Although this view omits many details utilized in such a drum printer they are not deemed necessary to an understanding of the present invention;

FIGURE 2 is a reduced scale, side View of the complete United States Patent O rotational mounting, one paper feed Wheel and the clock assembly with its adjustable reading head timing support disc;

FIGURE 4 is a detail end View of the reading head timing support disc taken on line 4-4 of FIGURE 3;

FIGURE 5 is a partially sectioned elevation view of the lower half of the print drum illustrating the relationship between the print drum, the frame end supporting plates and the paper feed components;

FIGURE 6 is a detail end view looking at the righthand side of the printer and illustrating the line feed solenoid and the relationship between its armature lever and the positive line feed clutch;

FIGURE 7 is a right-hand end View illustrating the mechanical linkage between the line feed cam (shown in FIGURE 6) and the line feed actuating pawl mechanism; and

FIGURE 8 is an exploded perspective view illustrating the means by which the total line feed power stroke may be varied to accomplish different amounts of paper feed.

GENERAL The major mechanical components of a drum form of page printer, including the line feedA arrangement pertinent to this invention, are shown in the skeleton arrangement of FIGURE 1 as an example of 4utility of the line feed mechanism. It will be generally described before proceeding with a detailed description of the line feed mechanism. The frame structure of the printer, the ribbon feed and reverse mechanism and various controls are not shown in FIGURE 1, however a representative somewhat similar drum printer assembly can be found in co-pending application Ser. No. 184,820 to which reference may be had, if necessary, for a complete understanding of the printer construction.

The printer is designed primarily for use in a sendreceive tele-printer set, being used for page copymonitoring and/'or page copy receiving.

A single hammer printer embodiment is capable of operating at nominal average speeds up to and including 200 w.p.m. and if dual print hammers are utilized, with double step character spacing, average operational maximum speed is appreciably increased, up to at least 400 w.p.m. Further multiplication of the number of hammers results in attaining of higher operational speeds which will necessitate related increase in rates of line feed.

In general, the printer mechanics 5t) employs a motor driven rotating type drum 52 which, for standard cornmunications printers, will have 72 rings of type, each type having the 52 standard communications symbols. The drum and its construction is fully described and claimed in the aforenoted pe-nding application Ser. 184,- 820 or divisional thereof and, per se, are not a part of the present invention.

Characters on each ring of type are similarly placed in binary order according to the Baudot code for the character, each character being assigned a position in -a 64 count binary progression so that the printer electronics can compare an incoming charater ode against a ode combination representative of the series of pulses subsequent to an index position which indicates the physical position of the drum characters relative to that indexing position. When comparison matches, coincidence, the electronic logic can determine exactly when to actuate the print hammer for printing the character when the drum rotates that character in front of the print hammer.

' The complete dum 52 includes on is cylindrical periphery a plurality of different horizontal lines of identical in- -formation symbols, for a conventional telegraph printer, seventy-two (72) identical symbols, e.g., seventy-two As, constituting one line of identical character type faces extending along the cylindrical drum periphery parallel to the drum axis. The drum 52 and an attached drum position clock wheel 58 are continuously rotated by a printer motor B1 when the motor is running. Related printer electronics are described in parent application 233,109.

As depicted in FIGURE l, a print hammer carriage assembly S4 is mounted for stepped spacing movement in a horizontal path from left to right and return movement from right to left in front of the type drum 52. The illustrated hammer carriage assembly 54 is universal in nature and can accommodate one or two print hammers with associated operating components.

The pri-nting mechanism includes an induction pulse clock assembly 56 which supplies one index pulse and a series of character position pulses to the printer electronics, representative of drum rotational position. Since each character position pulse represents a different character reaching a definite drum rotational position, the pulses constitute infomation which allows the printer electronics to energize the print hammer solenoid as the desired character moves in front of the hammer, or to actuate different machine functions if the received code signal combination are function signals.

The print hammer carriage 54 is stepped across in front of the drum 52 and parallel to the drum axis by spacing mechanism actuated by a spacing solenoid 6I? mounted at the right-hand side of the printer. Carriage 54 is power driven to a start-of-line position at the left-hand margin by a carriage return mechanism 62, seen at the left hand side of FIGURE 1. Carriage return mechanism is activated by the carriage return magnetic clutch 64, power for carirage return being derived, through clutch 64, from the printer motor B1.

Shown diagrammatically in FIGURE 2, a sheet paper strip record medium 65 is supplied from a paper roll 67 mounted behind the drum 52, the paper strip feeding over suitable glide devices (not shown), under and up past the front of the drum 52, passing between the drum S2 and the print hammer carriage 54 and under two side edge top guide lingers (not shown). The paper strip 65 then passes on out of the top of the printer unit Sti.

Paper feed is enabled by cooperation of two large friction banded feed Wheels at the ends of the drum and two presure rolls (see FIGURE under the drum which press the paper against the two large feed wheels which are selectively, incrementally driven.

Seen in skeleton form in FIGURE 1, an ink ribbon 69 Y passes across the duim face parallel to the drum between the print hammer and the paper to transfer the typed impresion from the drum to the page during a print operation. The ink ribbon assembly feed and reverse mechanism is conventional and details are not shown. However, the ink ribbon 69 in this printer passes in a straight stretch across the front of the drum 52 parallel to the character spacing pathof the print hammer, and the entire straight stretch of the ink ribbon if desired can be lowered and lifted by action of a ribbon lift solenoid 71 to a position in front of the hammer just prior to each printing action. This operation enables viewing of the line being printed without its being obscured by a permanently placed stretch of ink ribbon. Mechanism to accomplish thisribbon lift is not a part of this invention.

The printer components are mounted on a support structure which includes a thick base plate 66 (FIGURE 2) incorporating a slotted center track 68 (FIGUREI) which passes lateraly from one side of the printer to the other and under the path of travel of the print hammer carriage 54. Two vertical side plates 70 and 72 (see FIG- URES 3 and 5) are rigidly secured to the base plate 66 and provide mounting structure for most of the printer components. Support structure details are not shown in di FIGURE 1, but portions of the base plate and side .plates can be seen in some of the other figures.

The printer electronics is preferably transistorized and mounted either in a module 51 (FIGURE 2) on the back of the printer mechanics or incorporated in large printed circuit boards secured on the underside of the printer frame stucture.

The electric drive motor B1 supplies -rotational driving power to the printer mechanism Sti by means of a drive belt 11S which connects the motor to the drum shaft, a function power shaft and a carriage return clutch. Drive belt 118 passes around a drive pulley 116 attached to the motor shaft and to three driven pulleys 118, 120 and 122, pulley 12) being later referred to in more detail. To prevent slippage, the drive belt is notched and engages corresponding ygear teeth in each pulley.

Referring particularly to FIGURES 1, 3 and 5 the print drum 52 is preassembled in an lightweight inexpensive manner from a plurality of discs, preferably double type row wheels 76, manufactured to very close tolerances. A desired number of type wheels 76 are placed on the drum shaft 74, indexed t-o align all characters and clamped together by two end clamping plates 78, adjacent spacers 80 and nuts 82, the latter being threaded and torqued very tightly on intermediate threaded sections of the drum shaft 74. Both sets of clamping plates 7S, spacers Si? and nuts S2 are suitably locked together, after the clamping pressure is achieved. This construction is described and claimed in co-pending applications Ser. No. 184,820, filed April 3, 1962 and Ser. No. 481,796, led Aug. 22, 1965.

The clock wheel 58 is non-rotatably secured to the right-hand end of drum shaft 74 and has peripheral character reference notches 124 properly located relative to the angular positions of the print characters on the drum 52 and one index notch 126 located radially inside of the path of notches 124. The positioning of the monitor heads and 92 will provide one indexing pulse and 64 reference pulses once during each rotation of the print drum 52, although the index pulse is utilized only whenever the print drum starts to rotate. As the clock wheel 58 rotates with the print drum 52, the moving notches vary the reluctance of bar type magnets located in the clock monitor head coils 90' and 92 inducing appropriate current pulses into associated transistor amplifiers which are not described herein.

A left-hand bearing retainer assembly is placed over the left-hand end of the drum shaft '74. A somewhat similar right-hand bearing retainer assembly 84 (FIG- URE 3) and shaft bearing are placed over the righthand end portion of drum shaft 74. The right-hand bearing assembly 84, shown in FIGURE 3, is telescoped over a sleeve boss 86 which is integral with and projects from one side of a clock head mounting and timing disc 88. The disc 3S mounts the two printer clock monitor heads 99 and 92 in desired positions, as diagrammatically illustrated in FIGURE 1. By means of the two adjusting screws 93 and 93', illustrated in FIGURE 4, the angular position of the timing disc 38 relative to the print line can be adjusted to make incremental changes of the index and reference pulse count positions.

The drum end bearing retainers are clamped in sockets on top of respective printer frame end plates 70 and 72 by clamping caps such as the right-hand clamp cap 94 seen in FIGURES 3 and 4. The right-hand end plate cap 94 has two spaced apart lugs 95 on its outer face, the lugs having threaded bores that receive the two opposed timing disc adjusting screws 93 and 93', the ends of Ewhich engage an integral angular positioning finger 97 on the timing disc S8. Adjusting screws 93 and 93 are locked in adjusted position by lock nuts 99.

The purpose of the timing disc adjustment is to insure proper time correlation between the received character coincidence count pulse from the character clock head to the printer electronics and the print strokes of the hammer or hammers, correlation vdepending upon the angular fixed position of the clock heads, so that the printed characters are not cut olf at the top or bottom as depicted in FIGURE 3.

Referring to FIGURES 3 and 5, before the hubs of the drum end bearing retainers are positioned and clamped in their sockets -by the clamp caps, left and right-hand record medium feed wheels 96 and 98, with associated ring gears 100 and 102 are placed on external bushing sleeves made integral with the associated bearing retainers. The feed wheel gears may be integral or separable from the feed wheels. In the latter case they are clamped to the respective feed Wheels 96 and98 by screws 104. In either case split annular ring clamping plates 106 could be fastened to the sides of feed wheels 96 and -98 and fit into and ride inv grooves 108 in the non-rotatable end bearing retainer body, thereby axially maintaining the feed Wheels 96 and 98 in desired positions adjacent each end of and rotatable relative to the print drum.

A rubber ring 110 is stretched over the periphery of each :feed wheel 96 and 98 land fitted into half circle 4grooves 112 in the periphery of its feed wheel. The rubber ring can be preformed or it is cut or ground down so its outer periphery is almost even with the feed wheel periphery, thereby serving as a friction tire or band to engage and line feed the page record medium, by means to tbe hereinafter described. Note, the feed wheels are rotatably mounted on the bearing retainers which in turn are clamped in adjacent printer frame end plates 78 and 72 and the shaft of the print drum 52 is rotatably mounted in and extends through the bearing retainers. Drum and feed wheels rotate completely independent of each other.

The left-hand end of the drum shaft 74 projects beyond the left-hand frame end plate 70 and a gear toothed pulley 114 is non-rotatably secured thereto by set screws. Turning back to FIGURE 1, the printer motor B1, which will be mounted on the printer support structure inside of frame plate 70, is disposed with its shaft .parallel to the drum shaft 74 and carrying a toothed drive pulley 116. The notched drive belt 118 meshes with the teeth in motor pulley 116, and with the other three pulleys, the drum pulley 114, a function shaft pulley 120 and a carriage return clutch input pulley '122. As has been described hereinbefore, whenever the printer motor B1 is energized, the drum 52 will be continually rotating, and printing occurs on-the-ily.

Line feed- Referring generally to FIGURE l and specifically to FIGURES 5-8, the record paper 65 is fed through the printer one line (or more) at a time by the action of the line feed mechanism 138, different spacings of line feed being easily and conveniently changed, as will be hereinafter described.

Looking at FIGURE l, the motor driven belt 118, through the power shaft pulley 120', rotates the power shaft 121 which extends parallel and to the rear of drum 52 to the right-hand side of the printer mechanisms. Power shaft 121 is continually rotating and provides power for both the line feed and the ribbon feed and reverse mechanisms. The ribbon feed mechanisms (not shown) is operated continuously by the power shaft, and the line feed mechanism? 138 is selectively cyclically operated through the action of a positive action startstop clutch mechanism 142 whichcouples the right-hand end of power shaft 121 to a line feed cam 144.

Detailed construction of a suitable start-stop power shaft clutch is shown and described in Kleinschmidt et al. U.S. Patent No. 3,009,988 (see FIGURES 29-32 of that patent). Although the clutch stop plate of that disclosure uses only a single stop lug to accomplish 360 start-stop cycling, two lugs at diametrical positions' will enable 180 start-stop cycling.

FIGURE 6 illustrates the positive clutch 142 just after its plate is released so that the clutch is engaged to cam 144 and the cam has started to rotate. To accomplish clutching, the line feed solenoid 146 is energized, attracting the armature end 148 of the clutch stop lever 150, which pivots stop lever 150 clockwise on post 152 against the bias of spring 154 and removes the stop lever blocking end 154 from blocking position in front of clutch plate lug 156. This unblockng of the clutch plate 158 permits the clutch to make a positive connection between the power shaft 121 and feed cam 144, driving the line feed operating cam throughk180 degrees.

The line feed solenoid 146 is only momentarily energized (10 ms.) and long before the feed operating cam 144 can complete avhalf revolution, it has released the stop lever armature 148 which returns to its spring biased blocking position where lever blocking end 154 is engaged by the next stop lug 156 of clutch plate 158. Blocking of clutch plate 158 disengages the clutch 142 at the end of the half revolution. A clutch detent arm 159 and detent cam 160 fixed to the feed cam 144 ensures that the clutch 142 remains disengaged until the stop plate 158 is again released.

Line feed operating cam 144 is a dual cam, as shown in FIGURES 6 and 7, having two opposed identical radial rises 162 followed by abrupt drop-offs into identical dwells 164. A roller 166 on the end of a spring biased cam follower arm 168, disposed in the path of the cam lobes will be engaged by the operating cam and will make the follower arm cycle once for each 180 of operating cam rotation.

Shown in FIGURE 7, cam follower arm 168 is secured to a link 170 to form a dog-leg bellcrank pivoted on lpost 172. The cam follower bellcrank has a spring anchor finger 174 connected to one end of biasing spring 176, the other end of which is anchored on a post fixed to a support Vbracket 178. Spring 176 urges the cam follower counterclockwise so its roller 166 is urged toward the periphery of the feed operating cam 144.

Turning again to FIGURE 5, it will be seen that the aforedescribed feed wheels 96 and 98 at the ends of the print drum, advance the paper by rotation while pressing the paper against two pressure rollers 180 and 181. The two pressure rollers 180 and 181 are mounted on flat springs 182 which are fixed to a pressure roller release shaft 183. Attached to the pressure roller release shaft is a pressure release lever (not shown). When the pressure release lever is moved to the rear of the printer and latched, the pressure roller release shaft is rocked to move the pressure rollers 180 and 181 into spring biased engagement with the left and right edge portion of the paper record strip, pressing the paper record tight against the high friction, paper feed wheel lbands 110, thereby enabling controlled line feeding of the paper, by powered, incremental, simultaneous rotation of the two feed wheels 96 and 98.

Parallel to the drum axis and passing under the drum 52, and toward the front of the printer is a line feed shaft 186 rotatably 4mounted on brackets 188 and 190 secured to the printer frame. Shaft 186 extends through the righthand end plate 72 and through yand projects beyond its right-hand support bracket 190. Right and left line feed driving gears 192 and 193, non-rotatably attached to the `line feed shaft v186, mesh with and impart incremental drive to the gears 100 and 102 which are fastened on the paper feed wheels 96 and 98.

The paper record is rmly held in a given position or it can be fed one or more lines at a time by stepping a line feed ratchet wheel 194 non-rotatably secured on the projecting right-hand end of the line feed shaft (FIG- URES 5 and 7).

To keep the paper from inadvertently line feeding during printing, the ratchet wheel 194 is detained in its rotational position by a conventional line feed detent 196 shown in FIGURE .7. During line feed operation, the ratchet wheel 194 is turned one or two (or more) spaces by a spring Vbiased line feed pawl 198 pivotally mounted on a line feed pawl bail 200. Bail 200 is 4axially maintained and rotatably pivotally mounted on the projected end of line feed shaft 186, by a collar.

A post 202, fixed in one arm of pawl bail 200 is engaged by -a forked end 204 of the cam follower link 170 thereby enabling rocking movement of the feed cam follower to concurrenty rock the pawl bail 200 about the axis of line feed shaft 186. Counterclockwise rotation of the feed pawl bail 200 causes the line feed pawl 198, which is always biased into engagement with the teeth of the feed ratchet wheel 194, to positively rotate the feed shaft 186 against the detent action of the line feed detent 196. After the paper record is fed, by rotation of feed shaftA 186, the line feed detent 196 engages a tooth of the ratchet wheel 194 to prevent further inadvertent movement of the line feed gears. As the pawl bail 2&0 completes the return stroke of its cycle, pawl 198 ratchets back over the teeth of ratchet wheel 194.

The angular increment of rotation of the pawl bail 200 and thence, through pawl 198, to rotate the line feed shaft 186, depends upon the initial position of the earn follower roller 166 relative to the low dwell 164 of line feed operating cam 144. This initial position can be changed by changing the setting of a selector knob 206, FIGURES 7 and 8, to permit one, two or three lines to be fed per line feed solenoid operation. Knob 206 is formed on the end of a cylinder 208 with a through bore 210 enabling the cylinder to be rotatably disposed on a fixed post 212 under the lateral spring biased forked arm 174 of the cam follower bellcrank. Cylinder 208 is axially retained on post 212 by screw 214, but can be manually rotated on the post to a plurality of angular positions as determined by a spring loaded ball detent 216 located in an eccentric blind bore in the end of cylinder 208. The ball detent 216 is biased against the mounting pate 178 and engages an associated one of a number of small holes 218 located on a circular arc in plate 178, depending upon the selection.

In FIGURE 7, the knob 206 is positioned with the number 3 uppermost, indicating that each line feed operation will result in the feeding of the paper record, a distance of three lines. In the number 3 position, a large cam fiat 220 (see FIGURE 8) on selector cylinder 208 is disposed directly under a cam follower portion 222 of the bellcrank spring arm 174 which in the inoperative condition, is biased against the surface of cylinder 208 which is positioned uppermost, i.e., the cam flat 220. This permits the line feed bellcrank to rock counterclockwise a distance that drops the carn follower roller 166 all the way to the Ibottom of `a line feed operating cam lower dwell 164. Subsequent 180 rotation of line feed cam 144 resulting from energizing ofthe line feed solenoid 146 will lift the roller 166 to the top of a line feed cam rise 162 causing a clockwise power movement of the bellcrank follower sufficient to rock the pawl bail 200 counterclockwise a distance through which the pawl 198 drives the feed shaft 186 an angular increment to feed the paper three lines.

If the selector knob is set with the number 1 uppermost, the spring biased forked arm 174 of the cam follower lbellcrank will hit a high surface 224 on cylinder 208 and cannot move counterclockwise under spring bias as f-ar as it did in selector position 3. Therefore the cam follower roller 166 will not drop all of the way into a lower dwell 164 of the operating cam 144. Now, subsequent 180 rotation of operating cam 144 will only rock the cam follower under positive power :a small increment (about 1/3 of that previously described for setting number 3) resulting in movement of the feed pawl 198 an amount sutiicient only `to line feed the paper one space.

If the selector knob 206 is placed in position 2 the intermediate medium depth flat surface 226 is placed under the cam follower spring biased arm 174 and the cam follower bellcrank is permitted to rock through an angle halfway between that of a single line feed and a triple line feed, i.e., it will result in a double line feed. This selector mechanism is a very simple device for varying the length of line feed pawl power stroke, resulting in less work being performed for a single feed action than for a double or triple feed action. it is to -be understood that more than the three variations of line feed could be accommodated merely by suitably shaping the line feed operating earn 144 and the cam a'ts on the selector cy'linder 203.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. T he present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent is:

1. For use in a page record printer, a line feed mechanism for feeding a page record stepwise one or more lines spaces at a time including: page record engaging and feeding means; a ratchet wheel drivingly connected to said record engaging and feeding means; a ratchet wheel advancing pawl means :pivotally mounted adjacent and in engagement with the teeth of said ratchet wheel; a selectively operable, power driven cycling means for imparting a power and a return stroke to said pawl means; and means to selectively vary the magnitude of return stroke of said pawl means to thereby control the magnitude of power stroke and work applied to said pawl means by said power driven cycling means and chan-ge the magninitude of line feed.

2. A line feed mechanism as defined in claim 1, wherein said power driven cycling means comprises a startstop power cam, and a pivotally mounted cam follower arm, spring biased toward said power cam and connected to rock said pawl means; and said means to selectively vary the magnitude of said pawl means return stroke includes a control mem-ber, having a plurality of abutment surfaces adapted to |be selectively positioned in the return stroke path of a kinematic linkage which comprises said pawl means and said follower arm to block the return stroke movement of said pawl means at `different magnitudes of return stroke.

3. A line feed mechanism as defined in claim 1, wherein said power driven cycling -means comprises: a power driven, continuously rotating shaft; a rotatable cam c0- axially mounted relative to said power driven shaft; a selectively operable, solenoid controlled start-stop cycling clutch coupling said power driven shaft and said cam; Iand a cam follower pivotally mounted adjacent said cam for engagement by said cam and connected to said pawl means to enable rocking said pawl means to drive said ratchet.

4. For use in a [page record printer, a page record line feed mechanism comprising: rotatable page record engaging and feeding member rotating means; a ratchet wheel coaxially, non-rotatably secured on said rotating means; a ratchet wheel advancing pawl means pivotally mounted adjacent and in engagement with the teeth of said ratchet wheel; a selectively operable, power driven cycling means for imparting :a power and a return stroke to said pawl means; and means to selectively vary the magnitude of return stroke of said pawl means to thereby control the magnitude of power stroke and work applied to said pawl means by said power driven cycling means and change the magnitude of line feed; said power driven cycling means including a power driven, continuously rotating shaft, a rotatable cam with high and low dwells coaxially mounted relative to said power driven shaft, a selectively operable, solenoid controlled start-stop cycling clutch coupling said power driven shaft and said cam, a cam follower pivotally mounted adjacent said cam and connected to said pawl means to rock said pawl means, and spring biasing means connected to said cam follower and biasing said cam follower toward said cam.

5. A line feed mechanism as deiined in claim 4, wherein said cam follower is a -bellcrank with a cam `following means on one arm, its other arm vbeing connected to said pawl means, and an a-butment stop surface on one of said arms; spring means are connected to said bellcrank to bias its follower arm toward said cam; and said means to selectively vary the return stroke of said pawl means constitutes a selectively shftable stop member of said abutment stopv located in the path of movement surface in the direction biased by said spring means, different shifted positions of said stop member varying the limited position ofthe spring ybiased return stroke of said bellcrank and connected pawl means.

`6. A line feed lmechanism as dened in 4claim 5, wherein said shiftable stop member is a manually rotatable cylinder means having a plurality of surfaces located at dilerent ditsances from the axis of said cylinder means and shiftable into position to `be abutted lby said abutment surface by incremental rotation of said cylinder means.

7. A line feed mechanism as defined in claim 6, wherein a fixed support plate is provided to rotatably mount said cylinder means, said cylinder means is axially maintained with one end closely adjacent said plate, and detent means in said cylinder means and said plate cooperate to maintain selected positions of said cylinder means.

References Cited UNITED STATES PATENTS 2,038,929 4/1936 Fisher 741-124 2,561,755 7/1951 Recker 74-l24 X 2,965,204 12/1960 Howard 192-27 X MILTON KAUFMAN, Primary Examiner.

`FRED C. MATTERN, Examiner.

20 F. E. BAKER, Assistant Examiner.

Claims (1)

1. FOR USE IN A PAGE RECORD PRINTER, A LINE FEED MECHANISM FOR FEEDING A PAGE RECORD STEPWISE ONE OR MORE LINES SPACES AT A TIME INCLUDING: PAGE RECORD ENGAGING AND FEEDING MEANS; A RATCHET WHEEL DRIVINGLY CONNECTED TO SAID RECORD ENGAGINGB AND FEEDING MEANS; A RATCHET WHEEL ADVANCING PAWL MEANS PIVOTALLY MOUNTED ADJACENT AND IN ENGAGEMENT WITH THE TEETH OF SAID RATCHET WHEEL; A SELECTIVELY OPERABLE, POWER DRIVEN CYCLING MEANS FOR IMPARTING A POWER AND A RETURN STROKE TO SAID PAWL MEANS; AND MEANS TO SELECTIVELY VARY THE MAGNITUDE OF RETURN STROKE OF SAID PAWL MEANS TO THEREBY CONTROL THE MAGNITUDE OF POWER STROKE AND WORK APPLIED TO SAID PAWL MEANS BY SAID POWER DRIVEN CYCLING MEANS AND CHANGE THE MAGNINITUDE OF LINE FEED.

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