US2940521A - High speed punch - Google Patents

Description

June 14, 1960 J. H. Mac EI ETAL HIGH SPEED PUNCH 7 Sheets-Sheet x Filed June 7. 1957 INVENTORS, JOHN h. MAC/VEILL JAMES E. BELLI/VGER ATTORNEY June 14, 1960 J. H. MaONElLL ETAL 2,940,521

HIGH SPEED PUNCH 7 Sheets-Sheet 2 Filed June 7, 1957 INVENTORS, JOHN H. "ACNE/LL JAMES E. BELL/"GER ATTORNEY N wt June 14, 1960 J. H. M NEILL ETA!- 2,940,521

HIGH SPEED PUNCH Filed June 7. 1957 7 Sheets Sneot 3 F a oc0d ia$ 0 l H'l i if Q5 I l N "I3 I 1 a Q Lk k I I I I i g I Q l 1| INVENTORS,

JOHN H. MACNE/LL JAMES E. BELL/N65 ATTORNEY June 14, 1960 J. H. M NEILL ETAL HIGH SPEED PUNCH 7 Sheets-Sheet 4 Filed June 7. 1957 INVENTORS, JOHN H. "ACNE/LL JAMES E. BELL/N65,?

ATTORNEY June 14, 1960 J. H. MacNElLL ETAL 2,940,521

HIGH SPEED PUNCH Filed June 7. 1957 7 Sheets-Sheet 5 C o n Q 5 E a, g k t: a Q q t INVENTORS,

JOHN H. MAGNE/LL JAMES E. BELL/N65? ATTORNEY June 14, 1960 J. H. MacNEILL HIGH SPEED PUNCH 7 Sheets-Sheet 6 Filed June '7. 1957' thin s: at: SE E2 .v

llllllllllllL INVENTORS, JOHN H. MACNEILL JAMES E. BELL/NGER June 14, 1960 J. H. MacNEILL TA!- 2,940,521

HIGH SPEED PUNCH Filed June 7. 1957 7 Sheets-Sheet 7 INVENTORS,

JOHN H. MACNE/LL JAMES E. BELL/NGER BY M Mm ATTORNEY United States Patent HIGH SPEED PUNCH John H. MacNeill, Melbourne, and James E. Bellinger, Eau Gallic, Fla, assignors to Soroban Engineering, Inc., Melbourne, Fla, a corporation of Florida Filed June 7, 1957, Ser. No. 664,351

17 Claims. (Cl. 164111) The present invention relates to high speed punch devices for perforating record members, and more particularly to an improved record member feeding mechanism for high speed punch devices. Still more particularly the apparatus of the present invention constitutes an improvement of the record member punching and feeding mechanism disclosed in copending patent application, Serial No. 572,508, filed March 19, 1956, in the name of John H. MacNeill, for gh Speed Punch Devices, assigned to the same assignee as the present application and now matured into U.S. Letters Patent No. 2,859,816, dated November 11, 1958.

In the aforesaid copending application, there is provided a high speed punch device for selectively perforating a tape or other record member in accordance with a desired code such as a binary, trinary, hexadecimal, etc., code. The apparatus provides a vertically reciprocable punch bail disposed above a plurality of aligned and vertically arranged punch pins. The bail is reciprocated through a distance insuflicient to bring the bottom of the bail into engagement with the heads of the punch pins and in order to selectively actuate one or more of the punch pins a plurality of selectively positionable code interposers are provided. The code interposers are selectively slidable between first and second positions and in the second position couple the bail to the punch pins so that the pins are positively driven downward and through the record member.

A novel tape feed mechanism is provided in accordance with the aforesaid application employing a feed bail, a feed rod and a selectively actuatable interposer for coupling the feed bail to the feed rod. Upon coupling of the feed rod to the feed bail, the feed rod is driven downwardly and actuates a pawl and ratchet mechanism, the ratchet driving a sprocket wheel which engages a series of perforations in the paper tape. The ratchet is provided with a plurality of triangular teeth and the pawl is springbiased into engagement therewith so that upon downward movement of the feed rod, the forward end of the pawl engages the vertical surface of the sawtooth shaped-teeth of the ratchet to rotate it through a predetermined angle. The high speeds involved in such an apparatus require that the feed function, that is, feeding of the tape, be stopped at a precisely timed point in the cycle of operation, so that the tape does not move during the interval when the punches are pushed therethrough; since if such operation were fllowed, the punch pins would tear the tape. In order to positively stop the ratchet and prevent overshoot thereof in consequence of momentum imparted to the drive mechanism during the feed operation, the pawl at the limit of its driving movement is engaged by a pawl stop which jams the pawl against the sloping surfaces of the ratchet teeth, the positive positioning of the ratchet being established by means of a conventional detent. It has been found, however, that as'the speeds at which the apparatus is operated approach operating speeds of the order of magnitude of two-hundred and twentyfive cycles per second, indeterminate forces apparently Pat nted J ne 959 2 produced by backlash at the couplings between the various tape drive mechanism elements cause random overshoot of the drive sprocket, coupled with tearing of feed holes.

It is, therefore, an object of the present invention to provide a feed mechanism for high speed punch devices wherein the apparatus may be operated at cyclic rates greater than two-hundred and twenty-five cycles per sec"- ond without danger of overshoot of the drive mechanism.

It is another object of the present invention to provide a pawl and ratchet drive mechanism for high speed punch devices wherein the pawl is employed as an interposei which is selectively moved into engagement with a mu e; whenever it is desired to produce a record member feed operation. i

It is still another object of the present invention toprovide a feed mechanism for a high speed punch employing a pawl and ratchet drive mechanism wherein the awl is selectively engaged with the ratchet whenever it is desired to produce a feed operation and further wherein the relative shapes of the sprocket teeth and sprocket engaging tooth on the pawl are such that the pawl tooth prievents overshoot of the sprocket, there being further pro; vided a means for positively maintaining the pawl tooth in engagement with the sprocket teeth during the interval of (lo-acceleration of the ratchet and its associated structures. a V In, accordance with a first embodiment of the present invention, a pawl is rotatably mounted on a reciprocating shaft and has a tooth positioned adjacent the ratchet to be driven thereby. The pawl has two relative angular positions with respect to the rod ,on which it is rotatably mounted and in a first position the pawl tooth engages a tooth on the sprocket only upon obtaining its lower limit of downward movement. The pawl is adapted to be rotated, through the intermediary of the clec tromagnet into engagement with the ratchet teeth upon the pawl obftaining its maximum upward limit of movement so that upon subsequent downward movement of the pawl, the ratchet is rotated. The configuration of the pawl tooth and the sprocket teeth is such that upon the pawl obtain} ing its lower limit of movement, the pawl tooth is so positioned between the ratchet teeth that it is disposed iiitlic path of further movement of the ratchet teeth and thereby may prevent further rotation of the ratchet. In order to prevent the ratchet teeth from pushing the pawl out of the way, that is, from between the ratchet teeth, a positive pawl stop is provided. In consequence, the pawl and ratchet arrangement is such that the pawl limits the rotation of the ratchet through a fixed predetermined angle upon each downward movement of the. pawl.

The reciprocatable shaft on which the pawl is rotatably mounted, is connected via a link to the shaft upon the ratchet is mounted so that the reciprocatable shaft oscillates along an are having the same radius of curvature as the periphery of the ratchet. In consequence, when the pawl tooth is moved into contact with a ratchet tooth at the top of its stroke, the pawl tooth and ratchet teeth move along paths having the same radii bfcunvature and there is no relative movement between the teeth so that wear of the teethis almost completely eliminated.

The first embodiment of the invention described aboye materially extends the allowable rate of operation of the apparatus of the aforesaid copending application, but is also limited in its cyclic rate due to the impact'offthe pawl against the pawl stop at the end .of. each feeding cycle. In accordance with a second embodiment of the present invention the pawl stop may be eliminated or re tained if desired for other purposes, by theuseof .appropriate linkages which gradually reduce the rate fof rotational movement .of the pawl with respect to its drive shaft and which positively limit the allowable gi ugh? through which the pawl may rotate with respect to'its the pawl.

shaft. 'In this embodiment of the invention, a linkage is provided which selectively couples a crank for rotating the pawl with the center of a drag link interconnecting the'punch bail and anend of the drive rod remote from The center of the drive link is connected to one end of a link having a hook disposed on the other end thereof. The other end of the link is pivotally connected through appropriate linkages to the armature of an electromagnet which when energized moves the hook on the aforesaid link under one arm of a bell crank connected through an eccentric mechanism to the pawl. When the center of the drag link'moves upward, the bell crank is rotated so as .to'rota'te the pawl into engagement with the ratchet teeth,

upward movement of the'center of the drag link occur ring during an interval when the drive rod is being held in its uppermost position. Upon subsequent downward movement of the drive rod to produce rotation of the ratchet, the center of the drag link also moves downward at such a rate as to allow rotation of the pawl with the sprocket while maintaining the pawl tooth in intimate engagement with the sprocket teeth. Upon the drive rod reaching. its. downwardmost position, the center of the drag link reaches its downwardmost position and the pawl is brought to a stop with its pawl tooth positively positioned between the sprocket teeth. In consequence, the sprocket is brought to a stop at a precise location, and

overshoot ispr'evented.

" It is, therefore, another object of the present inven- ,tion to provide a drive mechanism for high speed punch devices employing positive de-acceleration and accurate positioning of a feed drive ratchet.

It is yet another object'of the present inventiontoproa' vide a high speed punch device employing a drag link for interconnecting a punch bail and feed drive rod so as to produce at the center'of'the drag link an appropriately timed motion which maybe employed for selectively,

coupling 'a pawl to a ratchet to produce rotation of the tage's of the invention will become apparent upon consideration of the following detailed description of two specific embodiments of the invention, especially when ratchet upon appropriate motion of the center of the drive i link and further to de-accelerate positively the ratchet and'bring it to a stop in a precise position.

i The above'and still further features, objects and advan taken in conjunction with the accompanying drawings,

wherein: V

Figure 1 is a perspective view of the punch device of the present invention illustrating mechanical details thereof; l r p G Figure 2 is a sectional view taken on the line 2--2 of Figure 1; Figure 3 is a detailed view of the punch bail employed in the present invention; 7

Figures 4 through 7 are enlarged detailed diagrams illustrating the elements of the feed mechanism of the first embodiment of the present invention in various positions during its cycle of operation; Figure 8 is a functional diagram illustrating the opera- 5 tion of the drive mechanism of the present invention;

Figures 9A and 9C are functional diagrams illustrating the interrelationship between the cyclic operation of the accompanying drawings, the apparatus of the present invention is provided with'a case having vertical side walls 1 and 2 and an intermediate vertical wall 3 which subdivides the case into two compartments 4 and 5, the vertical walls 1, 2 and 3 being partially broken away to more clearly disclose the apparatus of the invention.

Included within the compartment5 are the punching and feeding mechanisms of the apparatus and included within the compartment 4 is a mechanism for driving the punching and feeding mechanisms in isochronism. The mechanism included within the compartment 4 includes a shaft 6 perpendicular to and rotatably. mounted in the vertical walls 1 and 3. The shaft 6 extends through the wall 1 and has secured thereto a drive sprocket 7 driven by means of a belt 8 from a conventional source of rotary motion (not illustrated). Mounted on the shaft 6, for rotation therewith, is a cooling turbine 9 for cooling the apparatus by meansiof forced air draft. Second to the shaft 6 within the compartment 4 is an elongated, constant-diameter, triangular cam 10, the axis of the shaft 6 extending through the center of the radius of curvature of one of the cam surfaces of the cam 10. The cam 10 is called aconstant diameter cam since the distance between any two diametrically opposed points on its surface is equal to the distance'between any two other diametrically opposed points on its surface. The cam 10 is elongated along the axis of the shaft 6 sothat it may cooperate with and drive two cam followers 11 and 12. The cam follower 11 has a generally rectangular central aperture 13, the cam 10 being disposed within this aperture. The aperture 13 'provides'two cam engaging surfaces 14 and 15, the distance betweenthem being equal to the diameter of theconstant diameter cam 10 so that opposed points on the surfaces 14 and 15 are maintained in contact with the cam 10 atall times. In order to reduce wear on the cam lfland cam engaging surfaces 14 and 15, the cam follower 11 is elongated along the axis of the shaft 6 to thereby provide a relatively long line of contact between the cam 10 and the surfaces 14 and 15.

The surfaces of the cam follower 11 perpendicular to the axis of the shaft 6 extend outwardly from the main body of the cam follower 11 so as to provide lugs 16, 17, 18 and .19. One end of a link 20 is positioned between the lugs 16 and 18 and is pivotally secured to i the cam follower. 11 by means of a pivot pin 21 extending parallel to the shaft 6. The other end of the link 20 is secured to a shaft 22 perpendicular to and rotatably mounted in the vertical wall '3, the shaft 22 extending through both of the compartments 4 and 5. Alternatively, the shaft 22 may be mounted in wall 3 and supported by a bracket secured to'and extending from wall 3.- A second link 23 has one end positioned between and pivotally secured to the lugs 17 and 19 by means of a pivot pin 24 and has its other end pivotally secured to a shaft 25 which is perpendicularjto and mounted in the vertical wall 1. The cam follower 12 is identical in all respects with the cam follower 11 except that the cam engaging surfaces of the follower 12 are disposed at approximately for example, only, to the cam engaging surfaces of the follower 11 for purposes to be described subsequently. Links 26 and 27 each have one end pivoted to adjacent corners of the cam follower 12, and the other end of the link 26 is secured to a shaft 28' extending perpendicular to and rotatably mounted in the vertical walls 1 and 2, the shaft 28' extending through the wall 3 and into the compartment 5. The other end of the link 27 is pivotally securedto a shaft 28 mounted in wall 1. The shafts 22, 25, 28 and 28' are 'all partially broken away to clarify the illustration. Upon rotation of the shaft 6 and consequently of the cam 10, near-perfect reciprocab ing motion is imparted to the ' cam followers 11 and 12. As a result, of the 'fact that the cam'followers 11 and 12 contact two opposite surfaces ofthe cam 10, they are always positively positioned with respectto the cam, and spring loading of the cam followers may be eliminated. Elimination of spring loading of the cam followers 11 and 12' provides 'adrive apparatus free of resonant ef fects, spring fatigue and wear problems, and provides an apparatus wherein none of the force supplied by mere fitting shaft 6 must be utilized to overcome the force of cam follower springs. Thus, for a given load on the shafts 22 and 28 twice the work for a given contact area and pressure can be realized from this cam follower arrangement as from spring-loaded cam follower arrangements. In order to reduce wear of the cam 10 and cam followers 11 and 12, and also in order to materially reduce the noise incident upon the use of the apparatus, the compartment 4 may be filled with oil or other suitable lubricating liquid. Additional advantages deriving from the utilization of a constant diameter triangular cam will be discussed in conjunction with the feed and punch actuating mechanisms.

Proceeding with the description of the apparatus, the section of the shaft 22 within the compartment 5 has secured thereto at spaced points along its axis, the upper ends of punch toggles 29 and 30. The lower ends of the toggles 29 and 30 are pivoted to the upper ends of punch links 31 and 32, the lower ends of which extend into vertical slots 33 formed in an upper member 34 of a punch bail 35 (see Figures 1 and 3). The upper member 34 of the punch bail 35 is elongated perpendicular to the wall 3 and is provided with a cylindrical head section 36 and a downwardly depending generally rectangular section 37. A shaft 38 extends through the cylindrical 'head portion 36, the shaft 33 and cylindrical head portion 36 being coaxial. The lower ends of the punch links '31 and 32 extend into the slots 33 of the bail 35 and are pivotally secured to sections of the shaft 38 which are exposed by the slots 33. The lower surface of the generally rectangular portion 37 of the punch bail 35 is provided with a stair-stepped face 39 (see Figures 2 and 3), for cooperation with a complementary face on a punch interposer as will be described subsequently.

The punch bail 35 further comprises a lower member 49 positioned vertically below the upper member 34 and two guide members 41 (only one of which is illustrated in Figure l) which cooperate with walls 2 and 3 to guide the entire punch bail 35, for movement in the vertical direction, only. The rectangular section 37 and the lower member 40 of the bail 35 extend horizontally into engagement with the members 41 and are suitably secured thereto, or formed integrally therewith to provide a unitary bail structure as illustrated in Figure 3. The members 41 of the punch bail 35 are each provided on their ends with two vertically extending and parallel rectangular bars 42 (only one pair of which is illustrated in Figure 1) received in a pair of parallel vertically extending rectangular grooves 43 in the Vertical wall 3, and in a guide not illustrated near end wall 2. The legs 42 of the bail 35 reciprocate vertically in the rectangular grooves 43 but are restrained from horizontal motion by the sides of the grooves. Alternatively, the bail 35 may be guided vertically by suitably supported vertical pins, extending through. apertures in members 41 of the bail 35.

The lower member 40 of the bail 35 is provided with a plurality of transversely aligned, vertically extending apertures 44 which slidably receive therein a plurality of punches or punch pins 45 each weighing only a few grams. Eight such punches are illustrated, although it is to be understood that the invention is not limited to the utilization of any specific number of punches, the number of punches being determined by the overall system in which the punch device is to be utilized. An additional punch 46 is provided for punching feed holes in the record member, the punch 46 being driven by the section 40 of bail 35 and reciprocating therewith. The punches 45 are each provided with an enlarged head portion 47 greater in diameter than the apertures 44. The head portions 47 rest on the upper surface of the member 40 of the bm'l 35, the cooperation between the head portions 47 and the upper surface of bail sect-ion 40 constituting the vertical force for withdrawing the punches 45 from the record member after a punching 'opera tion. The punches 45 extend downwardly from the member 40 of the bail 35, and into a plurality of apertures 48 in a plate 49, the apertures 48 guiding the punches 45 laterally. The plate 49 constitutes the bottom wall of the compartment 5 and is secured to the vertical wall 3. A relatively loose fit is provided between the punches 45 and member 40 while a relatively snug fit is pro' vided between the punches 45 and the bottom wall 49.

Positioned immediately below the bottom wall .49 is a die plate 50, having apertures 50a aligned with the aper tures 48 in the plate 49. The die plate 50, which forms the top wall of a chad-receiving compartment, is spaced from the bottom wall 49 of the compartment 5 by a sufficient distance to allow the passage of a record member to be perforated therebetween. The record member may take any form such as a punch tape, punch card or any other member in which it is desired to provide a determinable configuration of perforations or marks.

The vertical motion imparted to the punch bail 35 by the toggles and links 29 through 32 is insuflicient to bring the punch bail 35 into engagement with the punches 45, The apparatus utilizes a plurality of punch interposers 51, one for each punch 45, to provide a mechanical coupling between the punch bail 35 and the punches 45 to produce a punching operation. The punch interposers 51 which are preferably fabricated from steel or like ma terials are horizontally slidable between the spacing or inactive position and a marking or punch actuating position and are illustrated in the spacing position in Figure l. The interposers 51 are provided at the forward end thereof, the left end as. viewed in Figure l and the right end as viewed in Figure 2, with a foot portion 52, the lower surface of which rests upon the heads 47 of the punches 45 under the stair-stepped portion 39 of the bail 35 when the interposers are in a spacing position. The vertical height of the foot 52 is insutlicient to be contacted by the bail 35 even when the bail 35 is in its lowermost position, and, therefore, when the interposers 51 are in spacing positions, a punching operation cannot occur. The foot 52 of the interposers 51 terminate in upwardly extending stair-stepped portions 53 which are complementary to the stair step configuration 39 of the punch bail 35. The other end of each of the interposers 51 is connected by means of a horizontal link 54 to one end of each of the armatures 55 of solenoids 56, the solenoids 56 being secured to the case members by suitable supports. The armatures 55 of the solenoid 56 are each pivoted about a shaft 57 extending perpendicular to and secured to the wall 3, the shaft 57 being vertically aligned with the pivotal connection between the armatures 55 and links 54. The solenoids '56 may be arranged in two banks one above and one below the links 54 to facilitate the positioning of the solenoids in a relatively narrow space. Positioned rearwardly of the armatures 55 of each bank of solenoids is a permanent magnet 58 which is employed to maintain the armatures 55 in the retracted or unactuated position. The magnets 58 are employed in place of springs so as to reduce the possibility of resonance in this part of the apparatus, as well as to provide a faster armature action by virtue of decreasing detent force as the armatures move toward their solenoids.

The solenoids 56 are selectively energized by an external source of electrical pulses (not illustrated) which may be arranged to supply pulses to the solenoids 56 in accordance with any known code such as binary, trinary, hexadecimal, etc., or may supply a single pulse at a time to effect punching of the record at a single predetermined location during each punch cycle. Upon energization. of the solenoid 56 its asociated armature 55 is pulled forward causing it to rotate about the shaft 57 andimpart forward motion to the link 54 and therefore to the inter posers 51 attached thereto. The interposers 51 therefore slide forward on the heads 47 0f the punches 45 and the stair step configuration 53 of the interposers become positioned immediately below the stair-'step 'configuration of the bail735. Thus, when the bail 35 descends, each selective interposer 51 is clamped between the bail 35 and a punch 45 and a positive downward movement is imparted to the punch 45 to produce apunching operation.

' The mechanism thus far described is substantially identical with that disclosedin the aforesaid copending application of John MacNeill with one exception which relates to the connection between the armatures 55 of the solenoids 56'and the link 54 connected to the interposers 51. In'the aforesaid application the solenoids .56 are mounted in vertical position with the armatures 55 disposed thereabove. The armatures 55 are connected to the links 54 through a fu1ther link which upon rotation downwardly toward the solenoids produces a forward motion of the links'54. The arrangement of the solenoids 56 and their associated armatures 55 as disclosed in the present application is employed to eliminate the one extra link interconnecting the armature 55 and the links 54. Proceeding now to description of the first embodiment of the novel tape feed mechanism of the present invention, reference is made' to Figure l and Figures 4 through 7. Mounted forward of the punch die plate'50 is a sprocket 59 having pins 60 for engaging a row of feed perforations in the record member; The sprocket 59 is secured to a hollow shaft 61 which is perpendicular to the wall '3. The hollow shaft 61 is coaxial with and rotatably mounted on a shaft 62rotatably mounted in the side walls of the 'chad receiving compartment. Secured to the shaft 61 is a ratchet 63 adapted to bra-intermittently driven by a pawl64 'rotatably mounted on a shaft 65, parallel'to but positioned forwardly and slightlyabove tliehshaft 62p A link '66 extends between the shafts 62 and 65 and is rotatably secured to both of the shafts, the link 66 restricting the shaft 65 to oscillatory'movenient aboutrthe shaft 62. The shaft; 65 is pivotally con nected to the lower end of a vertically'disposed drive'rod 64, the upper limit of motion being illustrated inFigures 4 and and the lower limit of motion being illustrated in Figure 6. The physical arrangement of the pawl 64 V and the sprocket 63 is such that when the pawl 64 is in the position of its lower limit of movement the pawl tooth 72 engages sprocket teeth 73 which are positioned along a radius of the sprocket disposed at 45 with the vertical radius of the ratchet 63. Since the teeth 73 are symmetrical and the two surfaces of each tooth intersect at 90, the upper surface of the tooth 73 engaged by the pawl tooth 72 is disposed in the horizontal plane and the adjacent surface of the next upper adjacent tooth 73 is disposed in the vertical plane. Therefore, the adjacent surfaces of the teeth 73'between which the pawl tooth 72 is disposed when the pawl is in its lowermost position are parallel to the horizontal and .vertical surfaces, respectively, of the pawl tooth 72. Movement imparted to the pawl 64 is such that the pawl moves a distance equal to the circumferential length of one, ratchet tooth 73 and if the pawl 64 is rotated clockwise when it is in its uppermost position as viewed in Figure 7 the pawl tooth 72 is positioned between two adjacent ratchet teeth 73 having a displacement of one tooth from the teeth engagedby thepawl tooth 72 when it is in its lowermost position. Therefore, upon downward movement of the pawl 64, the ratchet 63 is rotated counterclockwise through an angle equal to the displacement between two adjacent sprocket teeth 73. A pawl stop 74 having'a vertical surface 75 is positioned such that the surface 75 is contacted by the pawl 64 when it is in its lowermost'position and therefore provides a, limit stop for counter-clockwise rotation of the pawl and ratchet.

67- having its upper endpivotally connected to a feed link 68, the upper end of which is pivoted to the lower end'of a feed'toggle 69. The upper end of feed toggle 69'is sec'ured't'o theshaft28." A drag link 70 has one end piv otally'secured to the upper end of the drive rod 67 and the other end secured to the shaft 38 between the members '34-and'41' of the bail 35. q

The vertical motion'of the lower end of the feed link 68 resulting from oscillation'of' the shaft 28 is imparted to the drive rod 67 and therefore to the shaft 65 and pawl 64 which arefconstrained by the link 66, to oscillate about 7 the shaft 62. The main body of the pawl 64 is disposed to the left of the ratchet 63 as viewed in Figures 1 and 5 and is provided with an upper portion 71 extending to the'right as viewed in these two figures to a position hori zon'tally aligned with the eircumference of the ratchet 63.

The portion 71 of the pawl 64 supports a tooth 72 which extends horizontally to a position vertically aligned with the ratchet 63'and is of such a shape and size as to be insertable between two of the teeth 73 of the ratchet 63; More specifically "in the apparatus illustrated inthe accompanying drawings and for thc'purpose of explanation only, the tooth72of the pawl 64 has a right angle con figuration and in the position illustrated inFigure 4 has a horizontallyextending bottom surface and a vertically extending side surface disposed adjacent the ratchet 63, The ,teeth 73 on the ratchet 63 are arranged such that the adjacent surfaces of two adjacent teeth intersect at an angle of 90" and as illustrated are disposed at an angle ofhpproximately 45 with respect to the direction of movement [of the ratchet; Thus, when the pawl tooth :surfaces of the teeth 73 of thejratchet 63.: I

The'vertical oscillation of the shaft 65 about shaftpg establishesl pper and lower limits of'motion of theipawl The apparatus for rotating the .pawl 64 to a position as illustrated in Figure 7 comprises a'horizontally extending link 76 pivotally secured to the pawl 64, directly belowthe center of the shaft 65 when the'pawl 64 is in the angular position as illustrated in Figure 4 ofthe accompanying drawings. The left end of the link 76as viewed in Figures 4,6 and 7 is pivotally connected to one end of an upwardly extending armature 77- of a solenoid.78. The armature 77 is mounted on shaft 79 secured to the sidewall.

When it is desired to produce a feed operation, the

limit of movement and effects rotation of the armature77 counter-clockwise about the shaft 79 which in consequence moves the link 76 to the left as viewed in Figure 4. Movement of the link 76 to the left produces clockwise rotation of the pawl 64 about the shaft 65 to the position illustratedin Figure 6. Rotation of the pawl 64 about the shaft 62 when in its uppermost position'causes the tooth 72 to seat between two adjacent teeth 73 of the ratchet 63 and upon subsequent downward movement of the shaft .65 the ratchet 63 and consequently sprocket 59 are rotated counter-clockwise to produce advance of the record member; It will be noted that upon rotation of V the ratchet 63, the pawl 64 is rotated to the position illustrated in Figure 6 of the accompanying drawings, and therefore the pawl is reset to its normal angular position with respect to the shaft 62. Rotation of the pawl 64 to its normal position produces a movement of the link 76 to' the right, as the center of the shaft 65 falls below the horizontal plane of the. center of shaft 62, and results in clockwise rotation of the armature 77 of the solenoid 78 to its initial, position, that is, its position before the solenoid 78 was energized. ,A permanent magnet 80 is employed as a detent to hold the armature 77 in this position, thereby eliminating the need for springs to establish the'normalposition of the armature 77. The elimination of springs decreases the possibility of resonant effects in 'this portion of the apparatus.

. 9 tained during its rotation introduces problems with regard to accurate registration of the sprocket after each feed operation. More speciiically the high velocity attained by the sprocket 59, the ratchet 63, the shaft 61, the pawl 64, the link 66 and the members 67, 68, 65 and 76 taken in conjunction with the backlash between the various members permits limited continued rotation of the sprocket 59 after the driving force applied by the shaft 28 has ceased. In accordance with the present invention, overshoot of the sprocket 59 is eliminated as a result of the specific configuration of the ratchet teeth 73, the pawl tooth 72 and the physical relationship between these members and the pawl stop 74. When the pawl 64 ohtains its lower limit of motion as illustrated in Figure 6 the vertical surface of the pawl tooth 72 is disposed in the path of movement of the vertical surface of the tooth 73 of the ratchet 63 adjacent thereto. Thus, the vertical surface of the ratchet tooth 73 contacts the vertical surface of the pawl tooth 72 and since the pawl 64 cannot rotate counter-clockwise beyond the position illustrated in Figure 6 because of the pawl stop 74, the ratchet 63 is brought to an abrupt halt. A spring biased detent 81 is positioned adjacent the ratchet 63 and is provided with a roller 82 which engages the teeth 73 of the ratchet 63. The roller 82 of the detent 81 is positioned such that the ratchet 63 is allowed to rotate to a position, wherein the surface of the tooth 73 which was just previously engaged by the tooth 72 of the pawl 64 is positioned slightly below the lowermost limit of motion of the pawl tooth 72 and in consequence the tooth 72 does not contact the teeth 73 driving the cycles of operation when a feed operation is not desired, that is, when the solenoid 78 is not energized. Reviewing the operation of the tape feed mechanism, the pawl 64, when the solenoid 78 is not energized, reciprocates between the positions illustrated in Figures 4 and 6 during which it does not contact any teeth of the ratchet 63 and a feed operation is not achieved. The pawl 64 is maintained in the position illustrated in these two figures by the magnetic detent 80 acting through the solenoid armature 77 and link 76 which maintains the pawl 64 in contact with the surface 75 of the pawl stop 74. When it is desired to produce a record feed operation the solenoid 78 is energized when the pawl is at it supper limit of movement as illustrated in Figure 4 thereby rotating the pawl 64 into the position illustrated in Figure 7. Downward movement of the rod 67 advances the sprocket 59 counterclockwise through an angle determined by the number of ratchet teeth 73 and at the same time the pawl 64 is returned to the position illustrated in Figure 6 upon obtaining its downward limit of movement. The detent 80 positively retains the pawl 64 in position against the stop 74 during subsequent upward movement of the pawl 64 and the pawl rotates about the shaft 65 to its initial angular position with regard to this shaft as illustrated in Figure 4. It will be noted that the pawl 64 and the ratchet 63 both rotate about the shaft 62 during a feed operation so that the pawl tooth 72 and ratchet teeth 73 move along the same arcuate path. In consequence there is no relative movement between the teeth 73 and tooth 72 during a feeding operation and wear of these members is reduced to an absolute It can be seen from the above that the pawl 64 has the same function with respect to the feed mechanism as the interposers 51 have with respect to the punch mechanism. More specifically, a feed operation may or may not be achieved depending upon whether the solenoid 78 is energized and the pawl 64 is rotated into an active or feeding position.

As indicated above, the pawl 64 is reset to its nonfeeding in consequence of rotation of the ratchet 63.

Reset of the punch interposers 51 is not so simply achieved and since it is desired to eliminate springs from the apparatus wherever possible other means for resetting the punch interposers are provided in this apparatus. The

10 punch interposer reset mechanism is disclosed and claimed in the aforesaid application of John MacNeill and is repeated herein in order to provide a complete description of the apparatus of the present invention.

A punch interposer restoring bail 84 has an upper portion thereof positioned'immediately in front of and aligned with the foot portions 52 of the code interposers 51. The restoring bail 84 extends downwardly and is mounted on a shaft 85 which is perpendicular to and pivotally secured by lugs 85, extending upward from and secured to the plate 49. A link 86 perpendicular to the restoring bail 84 has one end thereof secured to the bail 84 and the other end pivoted to one end of a link 87. The other end of the link 87 is pivoted to the drag link 78 approximately halfway between the drive rod 67 and the shaft 38, which extends through the feed bail 35. Upon upward movement of the center of the drag link 76, the restoring bail 84 and shaft 87 are rotated about the center line of shaft 85 and the bail 84 presses against the forward end of the foot portions 52 of the code interposers 51 pushing them back to their spacing position where they are held by the magnets 58. It is stated above that the link 87 is pivoted to the center of the drag link 70 which is the correct location of this connection so long as the stroke of the lower ends of the links 31 and 68 are equal. As will be brought out subsequently, if it is desired to employ unequal strokes: for the lower ends of links 29 and 68, then the connec tion between link 87 and drag link 76 must be shifted to compensate for the change in phase of the cyclic move-v ment of the center of the drag link 70.

roceeding now to a description of the operation of the high speed punch device of the present invention, reference is initially made to Figure 8 for a detailed description of the punch and feed drive mechanism. The cam follower 11 is illustrated as rotated 90 with respect to the position shown in Figure l in order to prevent the punch toggle 29 and link 31 from obscuring portions of the cam 10 and cam follower 11. The operation of the cam and cam follower and punch toggles and links is the same regardless of the position of the cam and cam follower in space. At the start of each punch cycle, which is chosen as 0 and illustrated as such in the graph of Figure 8, the cam follower 11 is shown in its uppermost position A with the beginning of surface a and a of cam 10, having a constant radius with respect to the shaft 6, contacting the cam follower surfaces 14 and 15, respectively. The shaft 6 is rotated clockwise and through the first 60 of rotation of the cam 10, the cam follower 11 remains fixed in space since the surfaces a and a of the cam 10 remain at a fixed distance from the axis of the shaft 6 and no motion is imparted to the shaft 22. During this interval the link 20 is in its uppermost position and the punch toggle 29 and punch link 31 are in their leftmost position, and are disposed at an obtuse angle to one another. The punch bail 35 is therefore in its uppermost position and during this first 60 interval the selected code interposers 51 may be inserted between the punch bail 35 and the punches 45. Upon continued rotation of the shaft 6, surfaces b and b of the cam 10 having respectively a gradually decreasing and increasing displacement from the axis of the shaft 6 engage the cam follower surfaces 14 and 15, as illustrated in position B of the graph and the cam follower gradually moves downward in space. Downward movement of the cam follower 11 rotates the link 20 and therefore the shaft 22, counterclockwise, and the punch toggle 29 and punch link 31 have their interconnected ends moved to the right tending to straighten out this coupling, and therefore gradually moving the punch bail 35 downward, this being illustrated in the graph by the portion of the graph just to the right of the 60 position. Upon downward movement of thebail 35 it would appear that all of the punches 45 would move downwardly with the heads 47 of the punches 45 remaining in contact.

with the section 40 of the bail 35 untilthe lower'ends of. thepunches contact the record media. However, this is not the case. Taking into consideration the weight of the punches 45, only a few grams, the interval required for punching, approximately one-twelfth of the time required for one revolution of shaft, and the viscous damping provided by. oil which is maintained in the apertures 48, the unselected punches 45 fall only a very short distance, which is insuflicient to bring them into contact with the record media. Continued downward movement of the bail 35 clamps the selected interposers 51 between the bail section 34 and the heads 47 of the punches 45. 'Thedistance between the surface 53 'ofthe interposers 51 and the surface 39 on the bail 35, when the bail is in its upper position is quite small, only a few thousandths of an inch, so that clamping of the interposers 51 between the bail and the punches 45 occurs during a few degrees of rotation of the shaft when the bail 35 has a low velocity. As a result of the low velocity of bail 35 and'the resilience of the interposers, the interposers-51 are gradually clamped and impact on the bail 35, punches 45 and interposers 51 is minimized. Upon continued downward movement of the bail 35 the punches pass through the record .medium and reach their lowermost position at 120 .of rotation of the shaft 6, when the punch toggle 29 and punch link 31 are vertically aligned, a's-illustrated'in position C. Continued rotation of the shaft 6 brings surfaces 0 and c' of the cam' 10, respectively, having anlincreasing and a decreasing displacement from the axis of .the'shaft 6, into contact with the surfaces 14 and 1'5of the cam follower ll thereby rapidly deceleratingdownward movement of the cam follower 11. Upon further. rotation of the shaft 6, the toggle 29 and link 31, having passedthrough their vertically aligned position, become displaced toward the right, thereby pulling the bail 35 rapidly upward. In moving upward, the upper surface of the bail section 40 pulls up the actuated punches 45 withdrawing them from the record member and thereafter picks up the unselected punches, andreturns all of the punches 45 to their terminal position at 180 of rotation of shaft 6, as illustrated at position D, with the surface a contacting the cam follower surface 14, and a surface 15. Consequently, the lower section 40 of the bail 35 provides positive return for all of the punches, whether selected or unselected and springreturn of the punches is eliminated. The elimination of spring return of the punches 45 reduces the input power necessary to drive the punches and' also eliminates resonant effects normally introduced by the use of springs in a high speed reciprocating mechanical system. The surface a of the cam 10, which was initially in contact with the cam follower surface 15, is now in contact with the lower cam surface 14 and a dead period or period during which no motion is imparted to the cam follower 11 is again provided, for insertion of interposers for the next punch cycle. It will be noted at this point that during each. 180 of rotation of the shaft 6, the punch bail 35 is held at'an uppermost position for 60, driven from an uppermost position to a lowermost position, at 120 and back to an uppermost position again at 180". Therefore, the. punch toggle 29 and punch link 31 constitute a frequency doubling mechanism which operates the punch bail 35 at twice the rate of the rota tion of the. shaft 6. As a result, the drive mechanism of the present invention may be operated at one-half the desired punching rate, thereby. reducing high speed dy namic and wear problems in the drive mechanism.

The cyclic movement of the-toggles 68 and Y69 and of the link 67 of the record feed mechanism is identical with that of theltoggles 29-31, 30- 32 and bail 35, respectively, except forthe timing of the feeding operations. It is apparent'that a punching a'nda feeding operation cannotoccur at the same time, since such practicewould obviously result in ripping ofthe tape, and in order to maintainer predetermined interval between the operation 12 of the punch'mechanism and the feed mechanismythat is, to maintain these two'rnech'anisms in isochronismthe feed-cam follower 12 cooperates withithe same .cam 10 that drives the punch cam follower 11. However, the surfaces .ofthe cam follower 12 which contact the constant diameter cam 10 are disposed at 120 with respect to the surfaces 14 and 15 of cam follower 11 so as to provide the necessary displacement in time between the operation of thesetwo mechanisms. More specifically, a feed operation cannot occur while the punches are passing through or being withdrawn fromthe record member and conversely a punching'operation cannot occur while the record memberis. being moved by the. feed drive mechanism. Although the cam followers. 11 andz1 2 are disposed at 120 mechanically with respect to one another, the frequency doubling mechanisms in-.

' crease the angular displacement betweenoperation of the feed and punch mechanisms at 240 :of the cycle. Therefore, the cam followers 11 and 12 and unitary cam 10 maintain the feed and punch'mechanisms in isochronism, the feed actuating mechanisms having a fixed 240 lag with respect to the punch actuation mechanism insofar 'as cycle angle is concerned. It shouldibe noted that although it is preferable to employ a single cam 10 and phase displaced cam followers. 11 and .12, two' phase displaced or aligned cams on a common shaft or on separate and synchronized'shafts may be employed to cooperate respectively with two aligned or phase displaced cam followers 7 Y 7 Proceeding now to a description of the interrelated cyclic operation of the punch and feed mechanims,refer-- ence is made to Figures 9A, 9B and 90 of the aocompartying drawings. During the first 60 of rotation of the shaft 6, the selected solenoids 56 are energized to move. their respective code interposers 51 into the punch actuating position. At the end' of this interval, the feed toggles 68 and 69 become vertically aligned and the feedrod 67 has been driven downward to complete a feeding operation. During the first portion of the next-60 of rotation of the shaft 6, the feed rod 67 is moved upwardly returning the pawl 64 to:its uppermost position and'the punch bail starts downward'and pressest-he selectcd code interposers 51 between the bail35 and the punches 45. In Figure 9B, the links 29. and 31 are phase dis-' placed by 180 with respect to the illustration of links 29- and Slim Figure 8. The showing in Figure 9B is correct, the phase displacement of links 29 and 31 in Figure 8 being due to the fact that in Figure 8 the cam follower 11 was rotated from its true position in order to prevent the links 29 and 31 from obscuring the cam 10 and cam follower 11. Proceeding with the description, at of rotation of the shaft 6, the selected punches havebeen driven through the record member and the feed rod 67' has attained its uppermost position ready for the next feed operation. During the last 60 of the first half cycle i of revolution of the shaft '6, that is, 120 to the feed pawl 64 maybe again rotated to the feed actuating position inpr-eparation forthe next feeding cycle,

During the entire interval from 120 to 180, thepunches 45 are withdrawn from the record member andreturned to their position. During the interval, when the punches are being withdrawn, that is, during the interval= fron1120 to 180 of rotation of the shaft .6, the'punch interposers 51 are reset; At the 180 point of operationboth the feed and punch toggle-s69 and 29 andlinks 68 and 31, respectively, [are in their uppermost. position." with both toggles being inclined to the left. YThiSraises T the drag link 70, the drag link 70 lying in a horiiontaf' plane in this position, thereby raising the' link 137mm arm 86 and causing the restoring-bail 84 to be rotated about the center line of shaft 85 to press againstfthe punch interposers 51 and return them to'their spacing position. It will be noted 'thatwhe'n the apparatus ts in the 60. position the feed toggle. and are in" their lowermost, position while the punch toggle; and 'link 'are i in their uppermost position, these two positions being displaced respectively below and above the point of attachment of the link 87 to the drag link 70 by approximately equal distances. At the 120 position of the shaft 6, the feed toggle 69 and link 68 are withdrawn to their uppermost position and the punch toggle 29 and link 31 are extended to their lowermost position, the feed and punch links being displaced respectively at equal distances, above and below the point of attachment of the link 87 to the drag link '70. Therefore, the link 86 is maintained essentially stationary, the drag link 70 effectively pivoting about this point of attachement as a point approximately fixed in space. At the 120 position the left end of drag link 70p is raised and is maintained raised during the next 60", since the surface a of the cam engage respective cam surface of the feed cam follower 12 and the links 68 and 69 remain stationary during the next 60 of rotation of shaft 6. During this interval the links 29 and 31 move frorne their vertically aligned position toward the left and as the angle between the links 29 and 31 increases the right end of the link 70 is raised. The upper end of the code restoring bail is moved progressively toward the right and provides an increasingly inclined surface in contact with the ends 52 of the code interposers 51 thereby causing them to be reset. Consequently, even though an appropriate timing interval for code interposer reset is not provided by either the feed or punch mechanisms, an appropriate time for code'interposer reset is obtained by means of the drag link 70.

Proceeding with the description of the cyclic operation of the apparatus, during the interval from 180 to 240, the feed rod 67 is moved downwardlyto produce another feeding operation and, the solenoids 56 are selectively energized to move selected code interposers 51 into the punch actuating position. This cyclic operation of the feed and punch mechanisms continues through 360 of rotation of the shaft 6 and it can be seen that two cycles of operation of these mechanisms are produced during each rotation of the shaft 6.

The electromagnets 56 are excited when the bails 35 are at the tops of their strokes. At this instant the restoring bail 84 has fully reset the interposers 51 and is beginning to withdraw. If the electromagnets 56 are now excited, the interposer restoring mechanism will control the rate at which interposers are inserted in preparation for the next punch cycle. Thus impact of interposers against punch bail is controlled, and impact against a retreating restoring mechanism is eliminated. Reviewing the operation of the punch device of the present invention, the constant diameter triangular cam 10 permits allocation of one-third of each punch cycle to actuating interposers, one-third of a punch cycle to produce punching, and one-third to both withdrawal of the punches and resetting of the interposers. This timing applies equally Well to the feed mechanism but the punch cycle leads the feed cycle by 240 with respect to shit rotation which, due to the fact that a punching and feeding cycle occurs each 180 of rotation of the shaft, is equal to a 60 displacement between the operation of the punch bail and the feed rod. The specific angular displacement between the cam followers 11 and 12, although disclosed as 120, may be 60 or any multiple of 60 that maintains a displacement of 60 between the operation of the punch bail and feed bail since with this angular displacement setting of the feed interposed occurs while the punches are being Withdrawn from the record member following perforation. Proceeding with the description of operation of the punch device, a motion ideally timed for code interposer reset is provided at the center of the drag link 70, resetting of the code interposers occurring during withdrawal of the punches. The nearly vertical motion of the center of the drag link 70 follows the basic cam and cam follower motion and occurs in time midway between the occurrence of punch and feed strokes, a time ideally suited to code interposed restoration.

Thus, a restoring bail 84 driven with appropriate amplification from the center of the drag link 70 restores all code interposers 51 when both the punch bail 35 and the feed rod 67 are at the top of their respective strokes. The drag link 70 has an additional function of restraining the lower end of the feed link 68 to follow a substanitally vertical motion. The motion of punch bail and feed rod 67 is of the order of .030 inch. Thus, the are described by the link 70 around shaft 38 insures nearly vertical movement of the link 68.

The location of an appropriately timed motion at the center of the drag link 70 for resetting the code interposers is dependent upon the strokes of the lower ends of links 68 and 29 being made equal. If the strokes of the links are made unequal then the location of this motion shifts along the link 70 in a direction away from the link having the longer stroke. For instance, if the stroke of link 68 is twice that of the stroke of the link 29, then the link 87 should be connected to the link 7%) at a distance from the shaft 38 equal to one-third of the length of the link 70. The phase of the motion of this location on link 70 is the same as at the center of link 70 when the links 68 and 29 have equal strokes. It may be desirable to increase the stroke of the link 68 to greater than that employed for link 29 in order to minimize percentagewise, the effect of unavoided back-lash in the tape drive mechanism.

The tape drive mechanism has been described as utilizing'the rotatable pawl 64 for selectively actuating the feed mechanism. It is within the scope of the present invention to provide a permanent cyclic drive for the rod 76 to effect feed of the record member during each half cycle of rotation of the shaft 6. The utilization of a selectively actuatable feed mechanism is preferable in that it allows the punch to be operated at any speed up to synchronous speed as determined by the rate of rotation of the shaft. Thus, the punch device of the present invention may receive information from various sources, each operating at a different rate Without altering the basic operating frequency of the punch apparatus. During those intervals when the pawl 64 is not rotated, the punch 46 which punches the feed holes merely reciprocates in the hole it initially punched.

The feed drive mechanism illustrated in Figures 1 and 4 through 7 is somewhat limited as to its upper range of speeds in consequence of the impacts developed in the mechanism when the pawl 64 engages the pawl stop 74 after a feed operation. It is a well-known law of physics that the force which must be applied to decelerate a memher is equal to the mass of the member times the deceleration. Upon operation of the device at high cyclic rates such as 300 cycles per second, it has been found that the life expectancy of the drive mechanism is materially reduced due to the impact loads imposed upon the pawl 64 and the stop member 74. In order to extend the upper range of operation of apparatus of the present invention, the feed mechanism illustrated in Figure 10 may be employed. The punch mechanism remains the same as described above and illustrated in the aforesaid copending application of John MacNeill except that resetting of the code interposers may also be accomplished by electromagnets rather than by the restoring bail 84. Referring specifically to Figure 10 wherein the same reference numerals are employed for elements common to Figure 10 and the preceding figures, the drive rod 67 is again attached to the lower end of the drive link 68. The drag link 70 is now replaced by two identical and parallel drag links 70a, the left ends of these links as viewed in Figure 10 being pivoted to the links 67 and 63 and the right ends being pivotally secured to the side of the bail 35. The drive sprocket 59 is again mounted on a hollowshaft 61 having a ratchet 63 secured thereto. The shaft 61 is mounted coaxially of and is rotatable on the shaft- 62 which is secured in the side wall 3. The pawl 64 is rotatably mounted on the shaft 65 which is secured to the lower end of the drive rod 67; The shaft 65 extends past the drive rod 67 and has fixedly secured to the end thereof the lower end of a link 85. The upper end of the link 85 is pivotally secured to the left end of a gener allyhorizontally extending link 86 the right hand end of which is pivotally secured to a vertically extending and 87 of a bell crank 88. The bell crank 88 is pivotally secured to a rod 89 extending parallel to the shafts 65 and :61 and supported between the side walls of the apparatus; A horizontal arm 90 of the bell crank 88 is adapted to have its right hand end as viewed in Figure 10 selectively engaged by a hook 91 disposed on the lower end of a link 92 which has its upper end pivotally secured to the center of the drag links 70a. The lower end of the arm 92 is pivotally secured adjacent to the hook 91 to a horizontally extending link 93 the other end of which is pivotally secured to the generally vertically extending armature .77 of the solenoid 78. The lower end of the armature 77 is pivoted about a shaft 79 as in the preceding modification; The armature 77 is retained in an unactuated position; that is, rotated clockwise to a maximum extent by means of an electromagnet 94 which is 'maintained energized when the feed mechanism is to be maintained inoperative. With the armature 77 rotated clockwise the link 92 is rotated counterclockwise and the hook 91 does not engage the arm 90' of the bellcrank 88 as link 92 is vertically reciprocated by links 70a. When it isdesir'ed to actuate the feed mechanism, the magnet 94 is deenergized and the electromagnet. 78 is energized. 1E n'- ergization of the electromagnet .78 produces counter clockwise rotation of the armature 77 which through the link 913,.rotates' the link 92 about its pivotal connection to the drag links 70a,.until the hook 91 is disposed under the end of the arm 90 of the bell'crank 88. Upon upward movement of the center of the drag links at an appropriately timed interval to be discussed subsequently, the bell crank 88 is rotated counterclockwise and thereby produces clockwise rotation of the shaft '65 through the intermediary of the link 85. Rotation of the shaft 65 produces rotation of the pawl 64 to effect engagement between the pawl 64 and the ratchet teeth 73, this'occurring when the drive rod 67 is in its uppermost position. Upondownward movement of the drive rod 67 the ratchet is advanced ,one tooth position, as previously described, the detent 81 positively maintaining theposition of the ratchet between the downward strokes of the drive rod 67.

The apparatus illustrated in Figure 10 does not require a pawl stop as 74 in Figure 4, etc., since the pawl 64 is positively decelerated by the links 85, 86, bell crank 88, book 91, 'link 92 and'di'ag links 701;. As indicated in the description of the structure of the present embodiment, the pawl 64 is secured to the shaft'65-s'o as to rotate therewith and differs in this respect from the first embodiment wherein the pawl 64 is rotatable on shaft 65. So long as the hook 91 engages the arm 90 of. the bell crank 88 the rotation of the shaft 65 is directly under 16 indicating that a feed operation has just been completed andtthat a punch operation is just starting. Through the first 60 of motion, the punch ball moves to its lowermost position effecting a punching operation while the feed rod 67 moves to' its uppermost position; The two motions are complementary and in consequence the center 'of the drag links 70a remain fixed in space and the links 70a effectively rock about the center of'the links as a pivot point. During the next 60 interval, that is, from thei60 to 120 of rotation of the shaft 6 of the drive mechanism, the drive rod 67 is maintained in its uppermost position while the punch bail 35 is moved upward'ly to its uppermost position. Thus, the end of the drag link 70a secured to the drive rod 67 is held stationary while the end of the drag link secured to the punch bail 35 rises and in consequence the center of the drag link rises. If it is desired to feed tape during this cycle of the operation, the electromagnet 78 is energized during the first 60 of rotation of the shaft 6 so as to place the hook 91 under the arm 90 of the bell crank 88. Upon upward movement of the center of the drag links; 70a from 60 to'il20-*the bell crank '88 is rotated counterclockwise and the pawl 64 is brought into driving relation with respect to the ratchet 63. 'Duringthe interval'from 120 to 180 of rotation of the shaft 6, the punch ball 35 is maintained stationary at its upper limit of movement whilethe feed rod 67 moves downwardly to effect a punch operation; The center of the'links704 now move downwardly by an amount equal to one-half of the amount of movement of the drive rod 67 and the ratchet 63 is rotated through a distance equal to the displacement between'adjacent ratchet teeth73. During the latter part of the interval from 120 to- 180 of rotation of shaft 6, the drag links 70a approachtheir lowermost limits of their downward movement and are at first rapidly and then gradually decelerated.-. Since themotion of the center of the links 70a is translated into'the rotary motion of the shaft 65, the links 70a control the rotation of the pawl 64 and consequently the horizontal comcontrol, of the motion of the center of the drag links 70a. 'As will appear subsequently, the motionof the.

center of the links 70a is such that the pawl 64 is allowed to rotate counterclockwise about shaft 62 only through a sufficient angle to step the ratchet 63 one tooth position, and the pawl is stopped and positively maintained 7 in a position with its tooth 72 disposed in the pathof movement of the ratchet teeth 73. In addition, as will becomeapparent from the following description the ratchet is gradually decelerated as the pawl approaches the lower limit of its reciprocating motion. Referring specifically to Figure ll of the accompanying drawings,

' there isillustrated three curves A, B and C, the curve'A designating punch bail motion, the'curve B designating feed rod motion and the curve C indicating the motionof the center of the drag links 7 0a. Starting at zero degrees the punch bail 35 is at its .maximum upward position while the feed drive rod 87 is its lowermost position ponent of its movement. Further since his the horizontal component of the movement of the pawl 64 which eifects deceleration of the ratchet 5 9, the motion of the center of the links 70a controls the deceleration of the ratchet' 59 and imparts a gradual deceleration'thereto which minimizes impactloads on the pawl tooth and ratchet'teeth. Thus, the feed rod decelerates as well as accelerates the ratchet and feed sprocket. Although a detent is required to hold the ratchet betweenjsuccessive feed operations, an impact type pawl stop is eliminated.

Appropriate scaling of links and.86, and bell crank 88 coupled with proper, selection-of the exact angular positionat which pawl 64 is made to engage ratchet 73 also provides gradual preloading of the various drive members during a feed cycle. and eliminates backlash during feed. 7

As in the case of the first embodiment of the invention, the punch bail and drive rod are each maintained at the top of their cycle-for one-third of each cycle of operation, thereby permitting ample time for insert of the interposers 51 in the case of the pu nch mechanism and to rotate the pawl 64 into engagement with the ratchet 59 with respect to the feed mechanism. In the'embodiment of the inused for either forwardior reverse transportrof tape through the punch. Byreversing the direction of rotation of drive shaft 6 the pawl 64 may be engaged with therefore positively 17 ratchet 63 when drive rod 67 is at the bottom of its stroke. Upward pull of the drive rod 67 and link 92, through hell crank 90 will maintain pawl engagement as links 70a pivot in a clockwise direction. Thus it becomes possible to back up a previously punched tape through the perforator, without altering the mechanism illustrated in Figure 10.

It should also be noted that when the vertical motions of rod 67 and hail 35 differ, the pivot point for connection of link 92 should be shifted along 70a as described for interposer reset as illustrated in Figures 1, 2 and 9.

While we have described and illustrated two specific embodiments of my invention, it will be clear that variations of the details of construction which are specifically illustrated and described may be resorted to without departing from the true spirit andscope of the invention as defined in the appended claims.

What we claim is:

'1. A pawl and ratchet drive mechanism comprising a reciprocatable drive member, drive means for reciprocating said drive member, a pawl having at least one tooth, said pawl being rotatably secured to said drive member for reciprocation therewith and rotation with respect thereto, a shaft to be intermittently rotated, a rotatable ratchet secured to said shaft for rotating said shaft upon rotation of said rachet, said ratchet having a plurality of teeth, means for normally maintaining said pawl tooth out of engagement with said ratchet teeth, means for rotating said pawl to a position wherein said pawl tooth engages said ratchet between at least two adjacent ratchet teeth so as to enable rotation of said ratchet upon movement of said pawl in one direction, said means for reciprocating said drive member operating at such a velocity as to tend to cause said ratchet to continue rotation upon termination of movement of said pawl in said one direction, and means for preventing said continued rotation of said ratchet including means for maintaining said pawl tooth between said ratchet teeth for the interval during which said pawl is decelerated, said pawl tooth and said ratchet teeth having relative shapes such as to prevent relative movement between said ratchet teeth and said pawl tooth while said pawl tooth is maintained in engagement with said ratchet teeth.

2. The combination of claim 1, wherein said drive means includes means for maintaining said drive member stationary at said first position for an interval required to rotate said pawl into engagement with said ratchet.

3. A tape drive mechanism comprising a reciprocatable bail, means for reciprocating said bail between a first and a second position, a reciprocatable tape feed drive member, means for reciprocating said drive member between a first and second position, means for maintaining both said means for reciprocating in isochronism, a pawl having at least one tooth, said pawl being rotatably secured to said drive member for reciprocation be tween a first and second position therewith and rotation with respect thereto, a rotatable ratchet having a plurality of teeth, a tape drive sprocket for driving tape, said sprocket being secured to said ratchet for rotation therewith, means for normally retaining said pawl tooth out of engagement with said ratchet teeth, means for selectively rotating said pawl when it obtains said first position to a third position, wherein said pawl tooth engages said ratchet between two adjacent ratchet teeth so as to enable rotation of said ratchet upon movement of said pawl in one direction, from said thirdposition to said second position, said means for reciprocating said drive member operating at such a velocity as to tend to cause said ratchet to continue rotation upon termination of movement of said pawl in said one direction, and means for preventing said continued rotation of said ratchet including a pawl stop for maintaining said pawl tooth in engagement with said ratchet between said two teeth for a short interval when said pawl is adjacent its second position, said pawl tooth and said ratchet teeth 18 having relative shapes such that a substantially line contact is established therebetween during deceleration of said ratchet which line lies at an angle of at least the order of magnitude of 45 with respect to the direction of movement of said ratchet.

4. A tape drive mechanism comprising a reciprocatable bail, means for reciprocating said bail between a first and a second position, a reciprocatable tape feed drive rod, means for reciprocating said drive rod between first and second limits of movement, means for maintaining both said means for reciprocating in isochronism, a pawl having at least one tooth, said pawl being rotatably secured to said drive rod for reciprocation between first and second limits of movement therewith and rotation with respect thereto, a rotatable ratchet having a plurality of teeth, a tape drive sprocket for driving tape, said sprocket being secured to said ratchet for rotation therewith, means for normally'retaining said pawl in a first angular position with respect to said ratchet wherein said pawl tooth is disposed between two adjacent teeth of said ratchet only when said pawl is adjacent its second limit of movement, means for selectively rotating said pawl when it is adjacent its first limit of movement to a second angular position with respect to said drive rod wherein said pawl tooth engages said ratchet between two adjacent ratchet teeth so as to enable rotation of said ratchet upon movementof said pawl between its first and second limits of reciprocating movement, means including the relative paths of movement of said ratchet teeth and said drive rod for rotating said pawl towards its first angular position with respect to said ratchet upon rotation of said ratchet, said pawl being returned to its first angular position upon obtaining its second limit of reciprocating movement, said means for reciprocating said drive rod operating at such a velocity as to cause said ratchet to tend to continue rotation upon said pawl reaching its second limit of reciprocating movement, and means for preventing said continued rotation of said ratchet including means for maintaining said pawl in said first angular position with said pawl tooth in engagement with said ratchet between said two teeth at least when said pawl is adjacent its second limit of reciprocating movement, said pawl tooth and said ratchet teeth having relative shapes such as to prevent movement of said ratchet teeth relative to said pawltooth while said pawl is maintained adjacent said second limit of reciprocating motion.

5. The combination in accordance with claim 4, wherein said means for normally retaining said pawl in said first angular position comprises a magnetic detent.

6. The combination in accordance with claim 4, wherein said means for selectively rotating said pawl is a selectively energized eleotromagnet.

7. The combination in accordance with claim 4, wherein said means for maintaining said pawl in said first angular position comprises an abutment disposed in the path of rotation of said pawl and at the limit of rotation of said pawl from said second to said first angular position.

8. The combination in accordance with claim 4, wherein said means for maintaining said pawl in said first angular position comprises a drag link connected between said bail and said drive rod, and means selectively interconnecting said pawl and a point on said drag link intermediate said punch bail and said drive rod for establishing said first and second angular positions of said pawl as the limits of rotation thereof.

9. The combination in accordance with claim 4, wherein said means for maintaining said pawl in said first angular position comprises an element, means for moving a predetermined point on said element in accordance with a predetermined function of the movements of said bail and said drive rod, and means interconnecting said pawl and said point on said element when said pawl is driving positions of said pawl as the limits of rotation thereof.

10. The combination in accordance with claim 4

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