IL44924A - Selection mechanism for printer of the single element typ - Google Patents

Description

44924/2 οΐΒ'βη to nosin naiao may n*i*Ta iiaAja Selection mechanism for printer of the single ©lament typ© m usMosAb BUSINESS MAOHIEES CORPORATION 0/ 43060 SELECTION MECHANISM FOR A PRINTER OF THE SINGLE ELEMENT TYPE Abstract of the Disclosure A carrier for a printer, having a single type element, is disclosed. The selection apparatus contained within the carrier is one whereby only a rotary power force plus control signals need be introduced into the carrier. The selection apparatus is comprised of barrel cams having a plurality of channels formed into the periphery of the barrel cams to cause lateral displacement thereof on their drive shaft. The lateral displacement of the barrel cams is converted into a linear motion which is in turn transmitted and converted into rotary motion to position the type element about its rotate and tilt axes. The controls for transmitting signals to the carrier are pneumatic and the pneumatic impulses received by the carrier logic block and actuator blocks activate mechanical latches to insert selector pins into the grooves of the barrel cams . A dual rack and single pinion arrangement is disclosed to convert the linear motion to rotary motion of the type element.

Background of the Invention Singl e . element typewriters and printers have been known generally for quite some time. The fact that a single element typewriter with a fixed carriage requires a moving print carrier has in the past required extensive interconnections between the keyboard and the print carrier. This interconnection technique has primarily been through pulleys, tapes, cables, and the like which decode through a mechnical linkage a keyboard input and transmit that information to the carrier by means of differential lengths of tape r cord which are taken up through the movement of pulleys thus causing the type element to rotate and tilt the appropriate amount to position the desired character at the print point. The requirement for extensive mechanical interconnections between the main frame of the typewriter and the rotate -tile apparatus on the print carrier requires a very accurately manufactured side frame or power frame for the typewriter in addition to exceedingly accurate positioning of components on that power frame. Such tight tolerance requirements increase the cost of manufacture and require extensive adjustments to make the typewriter or printer work. properly. Also, during the manufacturing process it is necessary to build up each power frame piece by piece to produce the typewriter and then interconnect the appropriate decoding linkages and mechanisms with the piint carrier. These expensive manufacturing techniques and adjustment requirements not only are. tedious but provide additional possibilities for maladjustment.

Objects of the Invention It is a primary object of this invention to provide the capability for modular assembly and adjustment of · a single element typewriter.

It is an additional object £ this invention to minimize the interconnections between the keyboard and print' carrier of a single element typewriter.

It is a further object of this invention to ease the manufacture and adjustment of the selection mechanisms for a single element typewriter.

It is another object of this invention to eliminate mechanical control interconnections between the keyboard and the printer carrier of a single element typewriter.

Summary of the Invention The foregoing obj ects . are accomplished by the inclusion of the entire selection mechanism in the print carrier and the connection of the keyboard to the selection mechanism through either electrical or pneumatic means. The print carrier is provided with a translator to translate or decode the input signals which are in the form of pneumatic or electromagnetic signals and the decoding of those signals such that the keyboard originated output is converted into a plurality of signal pulses one corresponding to rotation of the type element, a second corresponding i j ■ .' · . to the tilt of the type element, a third corresponding i to a print/no print condition and a fourth corresponding to rotate direction. This converts the keyboard output to a set of signals capable of interpretation at the carrier and conveyed thereto through either pneumatic tubes or electrical conductors. This ι ' ■ eliminates the rotate and tilt bands, the associated pulleys , together with the mechanical decode, rotate and tilt mechanisms necessary to decocje the keyboard originated logic signals of the prior iart. The tilt and rotate signals are then fed to latches which unlatch selector pins and allow the pins to drop into a barrel cam. The rotation o the rotate barrel cam causes a lateral translation thereof with a corresponding lateral translation of a follower « linkage which is part of a linear to rotary motion converter. The linear to rotary motion c.onvertor translate the relative displacement of the barrel cam into a rotary motion of the typehead thus selecting the column of characters desired. Similarly, rotation of the tilt barrel cam results in lateral displacement of the tilt barrel cam as a result of its rotation and engagement with a fixed selector piri and is converted through bell cranks and linkages to a push-pull action causing the tilt ring of the print element rocker assembly to rotate about a horizontal axis thus positioning one of the characters within the previously selected row in the proper position for printing .

Continued rotation of the print shaft causes a plurality of cams to interact with detenting mechanisms for final head alignment and the activation of the print rocker by the engagement of the rocker arm through a follower wheel to the print cam. Upon. the completion of the impacting of the typehead into the platen, the type element or print head is returned to its home position, by the barrel cams rotation and subsequently restores the selection pins to their latched condition.

By the inclusion of the character selection mechanism within the carrier, interconnection between the keyboard and power frame with the carrier are eliminated except for data signal lines and the print shaft. The mechanical linkages necessary to control prior art selection mechanisms and then transmit the output of Those mechanisms to the carrier are eliminated simplifying manufacture, maintenance and enhancing the modular construction nature of the typewriter . .

A better understanding of the invention may be secured from a reading of the detailed description and viewing of the attached figures in the drawing.

Drawing Figure 1 is a single element typewriter having a carrier of the type disclosed herein.

Figure 2 is a left front perspective of part of the carrier of the typewriter illustrated in Figure 1.

Figure 3 is a partial simplified end view of the print cam and print rocker of the carrier of Figure 2.

Figure 4 illustrates the selector pin latch assembly together with the barrel cams in their home position.

Figure 5 is a section view along 5-5 in Figure 4.

Figure 6 illustrates the escapement linkage and the escapement cam carried within the carrier.

Figure 7 shows the no print control for controlling the cam follower of the print cam.

Figure 8 illustrates a partial top v ew of the 1 escapement cam and follower mechanism together with the 2 velocity and no print control. .3 · Figure 9 illustrates the selection rack and pinion 4 together with the reset control and detenting cam follower 5 and detenting mechanism of the print carrier. 6 Figures 10, 11, 12, and 13 are respective end and 7 section views of the barrel cams. 8 Figure 14 is a plan view of the rotate selection 9 cam. 10 Figure 15 is a cam diagram of the rotate cam of 11 [Figure 14. ' . i , 12 ; Figure 16 is a plan view of the tilt control 13 cam. 14 Figure 17 is the cam diagram for; the tilt barrel 15 jcam of Figure 16. ; 16 J Figure 18 is an exploded view of the motion 17 'conversion and transmission portion of the selection 18 apparatus. 19 Figure 19 is perspective view of a single selector 20 pin selector control and a partial view of. a single 21 track branched groove barrel cam. 22 Figure 20 is a schematic block diagram of a 23 suitable control network to provide signals to the 24 carrier of Figure 2.

LE9-72-032 Figure 21 is schematic of the single selection pin embodiment with the cam associated therewith stretched out to a cam diagram.

Figure 22, 23, 24 and 25 are sections of the cam of Figure 21 showing depth of various grooves at various cam stations.

Figure 26 is a plan view of the cam. represented by the. cam diagram in Figure 21.

Detailed Description To provide the printing function of a typewriter such as a single element printer or typewriter, a carrier 10 is provided within the typewriter 12.

This carriage is translatable across the print line of typewriter 12 on print shaft 14. The print shaft 14 is a rotatable shaft which provides the driving forces to the carrier 10 to cause activation of single print element 16. The control signal for the selection of the character on print element 16 are transmitted from keyboard 18 to the carrier 10 by means of control signal lines 20. Upon receipt of appropriate signals transmitted through lines 20 to carri er 10 , type element 16 is rotated and tilted to present the desired character in position opposite platen 22 such that when the type element 16 is impacted into platen 22 a printing operation occurs and a character or other symbol is deposited on page 24. ··'.

To provide the input , to the carrier 10 so that selection and printing may occur in the carrier 10, a keyboard 18 is provided. Keyboard 18 interacts with a keyboard signal generator 26. Keyboard signal generator 26 may take the form of pneumatic valves actuated by mechanical motion of the keyboard or it may be an electrical signal generator which is activated as a result of the mechanical operation of keyboard 18. Keyboard generator 26 provides the capability of producing plurality, n, of output signals. The signals generated by the keyboard signal generator are transmitted to a logic block 28. which then converts these signals into a series of m processed signals which are then outputed from the logic block 28 into an actuator block 30. The actuator block 30 receives the logic block outputs and converts these logic block outputs into a binary coded ομΐριιΐ of the keyboard key depression. The actuator block converts the pneumatic or electrical signal into a mechanical movement. In this case, the mechanical movement is the control of the rotate and tilt by selection latches 32 . Also outputed from the logic block, but not transmitted through the actuator block are additional signals representing ■ ί : . such functions as rack switch, no print,, and dead key. The utilization of these signals, directly by the mechanisms o the carrier, will be described in detail below.

As stated earlier, the keyboard signal generator 26 ,may be either pneumatic or electronic or any other i " · technique which allows the conversion of a mechanical physical motion of the keyboard 18 to be converted into a series of binary signals. These signals are then passed into a logic block 28. The function of the logic block is to convert a small number of signals from the keyboard generator 26 into a larger more comprehensive series of signals m which are outputed by the logic block and directly used . in a signal to mechanical motion converter or actuator block 30. Also, there are signals outputed from the logic block 28 which are used directly by the ' i carrier 10 to control ancillary non-selection functions such as dead key, no print and rack switch.

In order to more fully understand the operation of the actuator block 30, which is a signal receiving . means, reference is made to Figures 4 land .5. Actuator * I block 30, for sake of illustration, is shown as a pneumatic block in section view in Figure 5 and in broken away view in Figure 4 is made up of several components. The block member 32 is formed with a depression 347 This depression is sealed by flexible pneumatically distensible membrane 36 at points . i 38 in Figure 5. Points 38 in fact are edge sealing regions as opposed to physical points. The chamber 40 formed by distensible membrane 36 and depression 34 , is connected to the logic block through conduit 42. Conduit 42 provides a path to transmit signals from the logic block 28 into the chamber 40. In the case of a pneumatically actuated sjystem, the. depression of the keys of keyboard 18 provide a series of output signals from the keyboard, signal generator 26. These signals are received by and decoded by logic block 28 to provide signals for the actuator block 30. The logic block 28, through the logic network contained therein, provides an output signal in a pneumatic pulse form- and absence of pneumatic pulses in the event that a tilt or a rotate function or both are required of- the print element 16.

If a tilt or rotate is required to position print element 16 in its appropriate condition for subsequent impacting, a pressurized pulse of air is transmitted through conduit 42 and pressurizes cavit 40, as illustrated in Figure 5. As the pressure in. cavity 40 builds distensible membrane 36, exerts the corresponding pressure onto latch shoe 44. Latch shoe 44 is pivotally attached by pin 46. to a latch lever 48 * Latch lever 48 is pivotally mounted on pivot point 50 and biased in a counterclockwise direction by biasing spring 52. Latch lever 48 is further provided with a latching surface 54.

: Also provided on latch lever 48 is an extending tab portion 56. Tab 56 extends into a ballsometer or a ball tube interlock 57 which provides! a technique for preventing more than one latch lever 48 from being activated in response to a single set of rotate signals. and likewise only one tilt latch member 48 may be activated by a single set of tilt signals. The ball tube interlock technique is well known and well disclosed as a keyboard interlocking technique U.S. Patent 3 ,086 ,635 . rough the conduit ' an causes mem rane 36 to force shoe 44 and latch arm 48 to rotate in a clockwise direction around pivot point 50, latching surface 54 disengages from latch notch 58 of selector pin 60. Selector pin 60 is provided with a spring bias 62. . Spring bias 62 i is. a compression spring tending to force selector pin 60 in a leftward direction in Figure.5 and in a downward direction in Figure 4. Selector pin 60 is provided with a flatened blade portion 64.

This flatened blade portion 64 is adapted to engage with and ride in the selection grooves 70-76 and 170-173 of the selection and tilt barrel cams 68, 168. The selector pins 60 and their associated latches may be considered as selection means or positioning means as they provide selection of grooves and a fixed position for cams 68, 168 to rotate with respect to. '.' .■:·· .· . ■ To convert the actuation of a latch arm 48 into a usable motion for the purpose of translating the print head about the tilt and rotate axis, the blade portion 64 of selector pin 60 engages its respective track in the rotate or tilt cams 68, 168 illustrated in Figures 15 and 17. With. respect to the rotate cam, illustrated in Figure 15, there are a plurality of selection grooves 70-76. For the sake, of clarity, the grooves are indicated with 70-76, however, the units of relative selection displacement or units of rotation of the. head, is indicated by the unit digit of the reference numeral. For example, the groove labeled 70 is a zero displacement, home row or zero rotate condition. Groove 71 is a one unit 'rotate groove, groove 72 is a two unit rotate groove, and so on through groove 76 which is a Six unit rotate groove. Groove 78 is the groove into which a follower is inserted to provide translatory motion to the follower as a result of the translational movement . of the barrel cam 68. Each of the grooves 71 through 76 has a widened portion 80 to facilitate the entrance of selector pin blade 64 into the respective grooves .

Rotate barrel cam 68 is coaxially, slideably mounted on keyed rotating shaft 82 by means of projections 84 on shaft 82 and mating recesses 86 in barrel cam 68. This mounting technique provides a capability for barrel cam 68 to rotate in response to the shaft rotation of shaft 82. It also allows 'for a coaxial translation of barrel cam 68 with respect to shaft 82 in response to the selecting or picking of one of the selector pins 60 and the dropping of the blade portion 64 into one of the selection grooves 70-76. The translatory motion is caused by the blade portions 64 being held in a fixed position and the cam rotating around the axis of the shaft 82 thus causing the cam to displace laterally in Figure 4. Groove 78 of rotate cam 68 is an entirely circular groove which provides a recess for follower tab 88 to engage as seen in Figure 9. The function of follower tab 88 together with follower 90 will be more fully discussed below.

Zero select groove 70 is likewise a circular groove, with no radial dwells, rises, or falls. Engaged ■ . ■ ■ i . in ca groove 70 is a zero select homing pin 92, illustrated in Figure 4. Homing pin 9.2 is spring biased by compression pin 94 thus exerting a force on the homing pin 92 to cause it to move downward in Figure 4. This maintains engagement between pin 92 and zero rotate groove 70. Pin 92 remains engaged with groove 70 unless one of the pins 60 i . . . ■■ is released by its appropriate latch arm 48, and jallowed to engage its respective groove. In the jevent that one of the selector pins 60- is: allowed to extend and engage its respective rotate groove 71-76 in cam 68, the cam will rotate and pass the pin until it reaches approximately 90° of rotation.

At that, time, as can be seen readily from Figure 15, the pin will deviate from a straight path and attempt to follow the track. Since the pin 60 is fixed and the cam 68 is coaxially slideable on shaft 82, the cam 68 will translate in response to the deviation of the respective groove from the straight course.

This causes a direct translationa] movement of groove 78 44924/2 and thus causes follower tab 88 and follower 90 to move therewith.- Thus it can clearl be seen if the rotate grooves or selection grooves 71 - 76 are cut into cam 68 in such a way as to provide a proportional linear displacement corresponding to one through six units of t ranslational motion, the groove with the largest cam shift will thus be the six. unit rotate while the groove with the smallest shift will be the one unit rotate. As the cam 68 rotates after the engaging of a pin 60 into one of the rotate grooves . 71 - 76 and cam 68 begins its lateral translation, a radial as well as lateral camming surface 96 , is displaced under homing and zero rotate pin 92 , and thereby forces pin 92 against the biasing of spring 94 up the incline 96 onto external cylindrical surface 98 . The zero rotate homing pin 92 remains cammed out of track 70 until the rotation of the cam has been accomplished through approximately 270 ° of rotation at which time a complementary re e se camming surface 99 acts to allow the pin to descend into its engaged position as the cam is returned to its zero displacement position. At approximately 315 ° of rotation, the home select pin is substantially returned to its operative depth and is ready for engagement with groove 70 . At approximately 34 5 ° of rotation, home select pin 92 will be fully re-engaged with the track 70.

Referring now to Figure 11, which is a cross -sectional view of. rotate cam 68 in track 71, it can be understood how the blade portion 64 of a selector pin 60 can engage the track and be reset.

The blade portion 64 of selector pin 60 is inserted into groove 71 at a point approximatel at the 0° axis in Figure 11. As the cam rotates in a counterclockwise direction progressively presenting an increasing degree position of the cam circumference to blade 64, the cam profile 100 of the bottom of groove 71, forces the pin 60 and blade portion 64 radially outward during the rise and dwell portion of that camming action. As lobe 102 passes the 0° axis of Figure 11, the radial distance from the center of shaft .82' to the rise 102 is sufficient to compress spring 62 on pin 60 and allow bias spring 52 to rock latch arm 48 in a counterclockwise direction thus engaging latching surface 54 with pin latching surface 58. As cam 68 continues to rotate lobe 102 terminates at approximately 345° of rotation thus. allowing pin 60 to be positively latched by latch arm 48. At this time the cam has been rotated through one complete cycle of rotation and the cam has translated one unit of translation which will ultimately correspond to one unit of rotate. The selector pin 60 has been inserted into the groove 71, the selector pin 60 has guided cam 68 and has then raised out of the groove 71 and allowed to relatch in a retracted position. This has, at the same time, accomplished the camming of the zero rotate pin out of groove 70 up incline 96 onto cylindrical exterior surface 98 down descending cam surface 99 and return to groove 70. A similar mode of operation is possible if any other cam groove is selected by the unlatching of the appropriate selector pin . 60. The cam profile 100 and lobe.102 is identical for all the grooves 71-76.

Referring to Figure 4, the rotate cam 68 is forced toward the right on shaft 82 as shaft 82 rotates . . ' Referring now to Figure 9, follower tab 88 of cam follower 90 is engaged in follower groove 78. Follower 90 is slideably supported on shaft 110. Follower 90 includes a slot 112 for receiving rack tab 114.

Rack tab 114 engages slot 112 to receive the trans latory motion of follower 90 in response to the translatory motion of cam 68 transmitted through tab 88. Shaft ,110 is rigidly fixed into rocker 116 which is in turn pivoted upon a pivot pin 13.8. Rack tab 114 is rigidly attached to or formed into switchable rack 120. Rack 120 is pivotally mounted on and slideable on shaft 322 which is likewise carried by rocker 116. Cam follower 90 is likewise slideably mounted on shaft 122 as well as 110 as indicated earlier.

Referring to Figure 18, the bifurcated nature of rack 120 can be more clearly seen. Rack 120 has a dual arm arrangement with gear teeth formed in each arm. Rack 120 has gear racks 124 and 126..

Each rack 124 and 126 is formed on a separate portion of overall rack 120. The respective racks 124 and 126 are angularly disposed such that when rack 120 is tilted as far as it can be displaced in one angular direction, one of the racks, for example, 124 will be co -planar with and engage the teeth on pinion 128. Pinion 128 is fixedly mounted on the lower ball socket shaft 130. Lower ball socket shaft 130 extends up through the yoke 132 to the lower ball socket 134- which is formed as a part of the lower ball socket shaft 130.

To provide the facilities for selectively engaging oAe rack of the two racks 124, 126 of switchable rack 120, a shifter tab 136 is formed into the non- ' .' I · 'and forces necessary to shift rack 120 to engage rack '126, a rack shift mechanism 138 is provided. Rack shift mechanism 138 is comprised of an actuator lever 140. This lever may be actuated by either pneumatic or electromagnetic means. For the sake of illustration, a pneumatic actuation mechanism will be described, referring to Figures 9 and 18.

The pneumatic actuation mechanism is comprised of a bellows block 142 with an input port 144. Formed into the underside of bellows block 142 and communicating with input port 144 is chamber 146 which is sealed with a distensible membrane 148. Engaging the atmosphere side of membrane 148 is bellows member 1.50. Bellows ..member 150 is pivotally mounted on and spring biased around pin 152 by spring 154. Rack switch lever 140 may be attached to or formed at a part of bellows i member 150. The inflation of the bellows I50 will cause engagement between rack switch lever 140 and . rack switch tab 136 causing rack switching or shifting around shaft 122 in a counterclockwise direction as viewed in Figure 9.

To provide the resetting of the rack in its normal, home, minus rotate position with rack 124 engaging the teeth of pinion 128, a reset leaf spring 160 is provided. Reset leaf spring 160 is attached - - to rocker 162 which is pivotally attached to shaft 110.. Extending from rocker 162 are follower arms 164 and 166 as viewed in Figure 18.

In order to provide actuating inputs to follower arms 164 and 166, cam profiles are cut into the ends of rotate cam 68. These cam profiles 77 and 79 can best be observed in Figures 12 and 13. Follower arm 166 is positioned to engage cam profile 7 when the home or zero rotate pin 92 is engaged with its homing track 70. As cam profile .77 in Figure 13 is rotated/under follower arm 166 , the follower arm will ride up the cam profile 77 thus causing rack switch spring 160 to engage jthe lower portion of rack 120. As the rack 120 lis engaged arid forced upward by the continuing rise of follower arm 166 and its rotary action on rocker 162 and spring 160, the rack is forced to switch positions such that rack teeth 124 engage pinion 128 and rack teeth 126 disengage pinion 128. This switched position is maintained by overcenter spring i6¾ . Overcenter spring X*6"8 is attached to cam follower 90 which provides a tab 90*. The other end of the overcenter spring J 8* is attached to a tab 120' formed onto the switchable rack 120.

Cam lobe 77 is positioned at a location such that when enlarged portions 80 on the rotate cam 68 are presented to the blade 64 of selector pin 60 , the highest dwell of cam 77 is under follower 166 thus causing rotation and transmission of force through rocker 162 and leaf spring or rack switch spring 160. Thus it can be seen that as the rotate cam . 68 is positioned in its home or start position the rack switch cam follower 166 and the rack switch spring 160 act to always engage rack teeth 124 with pinion 128. This provides the capability of returning the. rack ,120 to a minus rotate condition upon the completion of each revolution of rotate cam 68.

The construction of rack switch bellows assembly 138 has been, discussed above. When a plus rotate condition. is desired, rack switch bellows assembly is pressurized through input port 144 leading to the moving downward of rack switch arm 140 to engage rack tab 136 causing rack 120 to switch thereby engaging rack 126 with pinion 128. ί .

. Inasmuch as rotate cam 68 only translates in one lateral direction during the first 180° of rotation of that cam, the engagement of rack 126 will create an opposite rotation of pinion 128 and lower ball socket shaft 130.

Cam follower arm 164 is positioned on shaft HO to cau-;. rocker 162 and hence, rack switch spring 160 to rotate. The distance between follower arms 166 and 164 is equal to the cummulative distance equal to the length of cam 68 between cam surfaces 77 . and 79 plus the distance which cam 68 will laterally translate when a selector pin 60 and blade 6 are caused to engage rotate slot 76 corresponding to six units of rotation. Cam 68 will translate on keyed shaft 82 but will only translate far enough ■ foIr cam follower 164 to engage cam lobe 79, illustrated in Figure 12, when a selector pin 60 and blade portion .64 are unlatched and engaged respectively into the groove 76 corresponding to six units of rotation.

If the rack is in a plus rotate condition with rack teeth 126 engaging pinion 128, the cam surface 79 will cause cam follower 164 to rotate about the axis ' of shaft 110, thus causing pivotal rotatin movement of rack switch' spring 160. The engagement of rack switch spring 160 with the underside of rack 120 at the point of the highest rise on the cam lobe 79, will cause rack 120 to change its position such that rack teeth 124 will engage pinion 128 and rack teeth 126 will disengage pinion 128. Cam lobe 79 is relatively positioned with respect to the other. cam surfaces of rotate cam 68, to present ' its rise and dwell to cam follower 164, at a time corresponding generally to the" beginning of the dwell in the trans lational motion of cam 68. Thus the rack is switched while there is substantially no translational movement of rotate cam 68 with respect to shaft 82. As the rotate cam 68 is rotated through the remainder of its 360° cycle, the cam 68 will translate in the opposite direction to its home position and thus be homed by zero rotate pin 92 engaging groove 70. Also any selector pins 60 will be restored to a latched position by the forces exerted thereo by cam rise 100 and cam. dwell 102.

In order to provide the necessary motion to tilt print element 16 about its horizontal axis to present a particular row of charact ers in a particular printing position, simultaneously with the presentation of a selected column of characters being positioned in a printing position, thus ' providing a single preselected character, a tilt cam 168 of the configuration illustrated in Figure 16 and its cam diagram illustrated in Figure 17, is mounted coaxial ly on keyed shaft 82. for coaxial sliding motion thereon Tilt cam 168 is formed with five grooves in th T generally cylindrical exterior surface. Grooves 170 through 173 denote selection or tilt increment grooves..

Groove 174 is the cam follower groc e and has no . /■ y translatory control over cam 168. To provide the mechanical input to the cam for the selection of a tilt increment, a latch and selector p(in assembly such as illustrated in Figure 5 is provided with a composite of three latches and selector pins , one each for grooves 171, 172, and 17ij. The three selector pins 60 associated with the three grooves 171-173 are interlocked through a ball tube interlock 57' among themselves but are not interlocked with respect to the selector pin latch assemblies for the rotate cam 68. The tilt cam 168 has a home or zero tilt groove 170. A non-latching, spring-biased, homing . selector pin 180 engages groove 170 to home the. tilt barrel cam 168 in its zero tilt or home location and thus control the position of the printing element ^6 in its zero tilt condition. Extending from the track 170 of cam 168 are camming surfaces 182 and 184. Camming surface 182 can be viewed in Figures 10 and 16 and 184 in Figure 10. The function of camming i surfaces 184 and 182 are respectfully the same as the functions of camming surfaces 96 and 99. They provide a rise and fall for the spring biased homing and zero r.ilt selection pin 180 thereby allowing that pin to ride out of track 170 when a selector pin 60 and blade section 64 have beonj engaged with tracks 171., 172, or 173. The notation convention utilized with respect to the rotate cam 68 is likewise utilized with respect to the tilt cam. wherein track • ■·..■ ' _ · · · Ί ; 170 represents zero units of tilt.. Tracks or grooves 171, 172, and 173 respectively correspond to one, two, and three units of tilt movement.

Track 174 provides a track for cam follower tab 186 which is formed as a part of bell crank 188. Bell crank 188 is pivotally mounted on supporting carrier frame 192 by pin 190. To provide. an output of the motion picked up from the translatory movement of cam 168, bell crank 188 is provided with an output . arm 194 which contains a connection 196 to tilt link 198;., Tilt link 198 to output its motion, is pivotally connected to tilt ring 200 by pivot point 202. Tilt ring 200 is pivotally attached to yoke 132 by pivot member 204.

The tilting of the tilt ring 200 which carries type element 16 on the upper ball socket 206, is accomplished by selection of one of the. selector pins 60 forcing the blade 64 into engagement with one of the tilt grooves 171-173 representing one, two, or three units of tilt. On the unlatching of one selection pin 60 in the pin block assembly correspondj r.g to the tilt function , the homing or zero tilt selection pin 1 80 will be cammed up surface 184 and the tilt cam 168 will translate in a leftward direction as viewed in Figures 4 and 8. ; This leftward ί ■ . : i ■ ; translation in response to the rotation of the cam 168 and further response to the rotation of. shaft 82 , causes cam follower tab 186 , in Figure 8 to translate leftwardly around pivot point 190 . For example,. if a letter is selected on keyboard 18 of Figure 1 , and that letter is positioned on type element 16 such that it requires a 'two unit tilt, selector pin 60 is. unlatched by latch arm 48 , acted upon by membrane 36 and shoe 44 in response to a pneumatic signal from logic block 28 , to cause blade portion 64 to drop into groove 172 . As groove 172 is progressively rotated past blade 64 , cam 168 will laterally translate along shaft 82 in a leftward direction by an increment corresponding to the increment required for a two unit tilt movement. This movement being picked . up by cam follower tab 1 86 causes bell crank 188 to rotate in a generally counterclockwise direction around pivot point 190 as viewed in Figure 8 . This causes output arm 194 and swivel connection 196 to pull tilt link 198 in a generally upward direction as viewed in Figure 8 . The upward direction of link 198 in Figure 8 corresponds to a generally down and leftward direction of movement for link 198 as viei-zed in Figure 9.' The downward and leftward movement of tilt link.198 translated through pivot pin 202 causes tilt ring 200 to rotate in a clockwise direction around pin 204. Upper ball socket 206 is connected to lower ball socket shaft 130 by conventional means well known in the IBM SELECT IC typewriter.

As tilt ring 200 rotates about pivot pin 204, upper ball socket 206 is carried therewith thus oreinting print element 16 such that the appropriate circumferential row of type characters are presented at the appropriate print line..

To provide accurate vertical placement, of the selected row of characters, a tilt det'enting mechanism is provided. The tilt detent mechanism comprises series of detent notches &6 respectively corresponding to the angular position of the tilt ring.200 for proper positioning of on typehead 16. These into an arcuate lower Referring to Figure 2, tilt detent 208 is formed as a part of tilt detent lever 210. Tilt detent lever 210 is spring biased. by spring 212 to be normally engaged, through tilt detent 208, with one of the plurality of detent notches W§ . Tetent crank 214 is 1 pivotally mounted on yoke 132 by means of a mounting 2 pin or screw 216. Detent lever 210 has a pivot 3 point at pivot means 218. Detent lever 2 LLO has a 4 depending leg 211 which is in turn engageable by 5 crank 214. The movement of crank 214 around pivot . 6 point 216 engages depending leg 211 of detent lever 7 210 acting against the bias of spring 212 to withdraw 8 the detent 208 from detent teeth 2&6 and allow free 9 movement of the tilt ring 200 in response to the liwk 10 tilt &ΑΆ$ 198. As an ancillary function, the withdrawal 11 of detent 208 from detent teeth 2 6 also acts to 12 move rotate detent 2*8* downward , as viewed in Figure 9, 13 to remove the detent surface 220 from the detent 14 teeth of type element 16. This allows the rotation 15 of type element 16 in response to the rotate selection 16 mechanism. 17 Crank 214 is moved pivotally around pivot point 18 216 in response to forces exerted on it by cam follower 19 222. Cam follower 222 is pivotally mounted to the 20 frame of the carrier 192 by pivot 224. Cam follower 21 222 has a follower tab 226 which engages detenting 22 cam 228 keyed to and mounted on rotary force receiving 23 . print sleeve 230. Print sleeve 230 is positively 24 driven rotationally by print shaft 232. ;: LE9-72-032 .

' To transmit the torque from print shaft 232 . and print sleeve 230 to the keyed shaft 82, a gear 234 is fixedly attached to print sleeve ;230. Gear 234 is engaged through idler gear 236 which is mounted on carrier frame 192 with cam shaft drive gear 238. Cam shaft drive gear 238 is fixedly attached to cam shaft 82 upon which tilt barrel cam. 168 and rotate barrel cam 68 are slideably mounted. The print sleeve 230 may be described as the power receiving means and the gear train keyed shaft and cams together with linkage driven by the cams translation may be described as the power utilizing means..

To- impart the necessary arcuate impacting movement for printing, to type element 16, and yoke assembly 132, rocker assembly 116 must be moved pivotally about pivot points 118. This is accomplished by transmission of a short duration force being applied to the. rocker assembly 116. This force is applied through a stud member 250 in Figure 3'. The force is provided to stud member .250 by print cam follower 252 which in turn is pivotally mounted at pivot 254 to carrier frame member 192. Print cam follower.. 252 further includes a cam roller 256 which is in rolling engagement with print cam 258., Print cam 258 has a high lobe for imparting movement . through ! : v print cam follower 252 to stud 250. Print cam 258 252, slideably mounted upon mounting pin 260 for trans lational movement along the axis of pin 260.

To provide a means for shifting print cam follower roller 256 out of engagement with cam 258 to produce a non-printing condition the slide member 262 is provided with a multiple latching therewith, and thus withdraw both their respective pawls from the latching surface 276 of slide member 262. Spring member 278 provides a constant bias on follower arm 280 and thus on slide member 262 which is engaged by follower arm 280. Slide member 262 has upturned tab shift yoke member 282 which ■X" : movement of slide member 262 is thereby translated into a corresponding lateral translation of print cam follower roller 256. With the withdrawal of latch members 264 and 274 from latching, surface 276, slide member 262 is thereby freed to translate leftward as in Figure 7 thus moving cam follower roller .256 out of engagement to the left and away from the cam rise of print cam 258. This lateral translation of roller 256 out of engagement with any of the cam. lobes of cam 258 has the effect of disconnecting the motion normally accorded print cam follower 252, due to rotation of print shaft 232 and print cam 258.

To restore slide member 262 to its normal operating position, follower arm 280 is provided with a cam 'follower lug 286. This cam follower lug is acted upon by restore cam 288 which is in turn mounted upon and rotates with print sleeve 230. The rotation of the print shaft 232 and the print sleeve 230 causes the restore cam 288 to engage cam follower. stud 286 and thus move follower arm 284 thus pushing slide member 262 rightward restoring the print cam follower wheel 256 to its normal operative position.

To normally cause escapement of the carrier with respect to the print line, and an escapement 44924/2 cam 300 is rigidly fixed to print sleeve 230, as illustrated in Figures 6 and 8. Escapement cam 300 rotates with print sleeve 230 and pr Iint shaft 232. Escapement cam follower 302 in the form of a bell crank, is provided with a follower wheel 304 in engagement with the periphery of escapement cam 300. Escapement cam follower 302 is pivotally mounted on a pivot pin 306 which in turn is supported by carrier frame member 192. Pivotally attached t •oI the other arm of the cam follower' bell crank 302 at pivot point 308, is escapement link 310.

Escapement link 310, escapement follower bell crank 302, and escapement follower wheel 304 are all biased into a position, whereby escapement follower wheel 304 is in engagement with periphery of escapement cam 300, by means of a spring 312. Escapement link 310, includes depending and upstanding tabs 314 and ,315 respectively. Depending tab 314 of escapement link 310 engages escapement pawl tab 316 which is formed on the end of the escapement pawl 317 . This is to provide a means for extracting the escapement pawl from the escapement rack to cause escapement of the carrier with respect to the print line. The addition of tab 316 to escapement pawl 317 is a modification made to the esca ement awl assembl as tab 314 from escapement pawl tab 316, any movement of the escapement linkage will be ineffective to cause escapement.

Description of Operation ! A better understanding of the mode of operation of the invention will become apparent from the detailed description of the operation of the invention described below .

,·. Referring particularly to Figure 1, upon the initiating of a key stroke at the keyboard 18 of typewriter 12, necessary signals will be generated and transmitted through signal carrying member 20 to the print carrier 10. The signals will be utilized at the carrier and (selection will occur within the carrier 10 thus ! . ' .. · . ■■ I ·■■ rotating and tilting print element 16 to present the preselected character to writing page 24 against "I. · ' ' platen 22 in response to the rotation 'ofj print shaft 14.

Referring now to Figure 20, upon the depression. of a key member of the keyboard 18, a keyboard signal generator 26 generates an electrical, or pneumatic . signal representing that character. These signals are then transmitted to a logic block 28 where the signals are decoded and recoded providing m outputs .

The. number of the outputs is dependent upon the lumber of functions that are to be effected as a result of direct, signals from the logic block. The i . ■ ■ . '.· * . ·. ' ■ . ' · ' ' ' signals are split, some of the signals going to an actuator -72-032 block 30 where each signal from the output block is received and utilized to actuate a mechanical mechanism for further control of the typehead 16 and carrier 10.

In this particular example, actuator block 30 will receive nine signals, one for each of the three tilt selection latch/selection pin assemblies |and one for each of the six rotate selection latch/selection pin assemblies. Additional signals for dead key, no print, and rack switch are routed directly from the logic block to the appropriate transducer on the carrier to effect those functions. Other signals may be provided as needed or desired.

As a result of the outputs of logic block 28, two signals will be received at the actuator block in a form vjhich will activate appropriate tilt and rotate selection latches 48 and selection pins 60. For the. sake of under-standing specific examples will be used but the reader will fully appreciate that the process in general is the same regardless of the position of the printhead desired, and that the operation of the carrier is substantially tjhe same for analogous cases with only different pins oeing selected as a result of different signals bein received in the inlets 42 to the pneumatic actuators for the latch levers 48 of the pin selection mechanism.

By way of example, the operator of the typewriter selects the letter lowercase "r' by depressing the keybutton corresponding to "r': . This generates signals which are LE9-72-032 passed through logic block 28 and result in output signals from the logic block in the form of two pneumatic pulses. One pneumatic pulse is directed to the selector pin 60 corresponding to groove 74 in rotate cam 68. The other pneumatic pulse is outputed through the actuator block 30 and latch assembly corresponding to the selector pin 60 mating with tilt groove 172 of tilt cam 168. The pulses are received in inlet port 42 of actuator block 30. The pressure in chamber 40 rises sharply distending diaphragm 36 and applying a force onto shoe 44 thus forcing latch lever arm 43 in a clockwise direction around pivot point 50. Rocking latch lever 48 in a clockwise direction withdraws latching surface 54 from latching surface 58 of selector pin 60. Under the influence, of compressed spring 62, blade 64 extends into groove 74 of rotate cam 68.

Following an identical analysis of the action of the parts, selector pin 60 and blade 64 will extend likewise into groove 172 of tilt cam 168. The depression of the print key corresponding to the letter "r" through well known techniques, acts to release a single cycle clutch (not. shown) to cause. the print shaft 232 to begin to rotate. As print shaft 232 rotates, print sleeve 230 rotates therewith causing gear 234 to rotate. The angular motion of gear 234 is transmitted through idler gear 236 in matched . relationship therewith, to the driven gear 238. Gear 238 LE9-72-032 is fixedly attached to keyed shaft 82. Thus the rotation of gear 238 causes rotation of shaft 82. Inas-much as the keying of shaft 82 is complimentary to the keyed core or holes through the centers of tilt cam 168 and rotate cam 68, tilt cam 168 and rotate cam 68 revolve with keyed shaft 82, Selector pins 60, having previously been inserted under the influence of compressed springs 62, into grooves 74 and 172 respectively,, the rotate and tilt cams begin a lateral displacement in correspondence to the displacement of the cam grooves 74 and 172. The rotate cam 68 and the tilt cam 168, translate on shaft 82 generall in opposite directions and toward their respective ends of keyed shaft 82. This direction of translation of each cam 68, 168 prevents an interference in the center of the shaft 82.

Inasmuch as rack member 120 is oriented with rack teeth 124 engaging the teeth at pinion 128, and this condition has been arbitrarily designated as a minus rotate conditior., the movement of the rotate cam 68 will cause a translation of rack 120 with respect to the carrier frame 192. That translation, since pinion 128 is fixed spacially with respect to the carrier frame 192, will cause rotation of the pinion 128 in a clockwise direction when viewed from above. As rotate cam 68 rotates about the axis of shaft 82, tilt cam 168 is likewise rotating in synchronous motion therewith.

LE9-72-032 Inasmuch as a selector pin 60 has been inserted into groove 172, as tilt cam 168 rotates the cam will translate a distance corresponding to two units of tilt of the printhead 16 during the course of approximately one half revolution of the cam. This translation 'causes groove 174 to likewise translate in a leftward direction as viewed in Figure 8. As groove 174 translates leftward, cam . follower tab 186, a part of tilt bell crank 188, will translate leftward thus pivoting cam follower tilt bell crank 188 about pivot point 190. This motion will act to rotate follower bell crank arm 194 in a counterclockwise direction thus pulling, through connection 196, the ti'lt link 198 in a generally upward direction as viewed in Figure 8. 1 ! Referring now to Figure 9, the motion of tilt link 198 referred to immediately above, corresponds to a dojwnward leftward motion of tilt link 198. This extension of tilt. link 198 acting through pivot pin 202 causes tilt ring 200 to rotate in a clockwise direction around pivot pin 204. This rotation of tilt ring 200 around pivot pin 204 is permitted by the extraction of tilt detent 208 from detent notches ¾ft6. The extraction of detent 208 from detent notches 2Φ6 is accomplished by the timed relation of cam 228 which is directly driven by print shaft 232 through print sleeve 230. The rise and high dwell of cam 228 acts through follower stud 226 to rock the follower 222 about pivot 224. The rocking of follower 222 about LE9-72-032 pivot 224 acts through detent crank 214 and pivots.it about its pivot point 216. The pivoting. of detent crank 214 around 216 engages depending leg 211 of detent latch member 210. The exertion of a force by detent crank 214 through detent latch leg 211 rotates detent latch 210 about pivot point 218 against the force of spring 212 and lowers the detent 208 out of the detent teeth 2Φ6 in tilt ring 200. This frees the tilt ring 200 for relatively free moving motion about pivot point 204. The high dwell of detent cam 228 is formed and positioned to allow the entire tilting operation to occur and to maintain detent member 208 out of engagement with detent teeth except at! that point in the cycle where the head is to be detented in a particular position for printing. At all other times of the cycle, the high dwell of detent cam 228 acts through th!e above described linkages and relationships to remove and keep removed from detent teeth ¾&6 , the detent 208. As detent cam 228 rotates during; the printing cycle, the low dwell will allow detent cam follower 222 to swing out of the way from detent crank 214 thus releasing the forces against pending leg 211 of detent member 210.

Spring.212 being freed to act, will then pull detent 208 into engagement with the appropriately alined detent teeth ¾θ>6. This immediate sequence of operations will occur just prior to the actual printing operation where LE9-72-032 rocker 116 is pivoted about its pivot pins 118 to impact typehead 16 into printed page 24. After printing, tilt detent 208 is extracted from the detent tooth as described earlier to allow the head to be returned to its home position in response to the continued operation and i revolution of tilt cam 168. The detenting operation occurs generally during the stationary dwell time as illustrated in Figure 17 as that time between approximately 180° of rotation and about 245° of rotation of the tilt cam.

The above sequence is that of the motion converting and transmitting means to convert and transmit the motions of cams 68 and 168 to rotate and tilt motions of typehead 16.

Simultaneous releases result from the extraction of detent 208 from detent teeth 3Φ6. Rotate detent 2*8 is forced down against the force of spring 219 by detent 208, to retract detent surface 220 from the detent teeth of print element 16.. Rotate detent 218 will remain extracted from the detent teeth of print element 16 as long as. the tilt detent 208 is extracted from the tilt detent teeth 2 6.

Thus the typehead 16 has been simultaneously freed for restoration to its home position both in the tilt and the rotate axes .

As both the rotate and tilt cams are rotated past the high dwell region, the descending slopes of the respective grooves 74 and 172, cause translation of the two cams 68 and 168 toward each other and back toward their respective home positions. As they return to their home positions, homing pins 92 and 180 ride down descending cam slopes 99 and 182 respectively to reposition their tips within the homing tracks 70 and 170 of cams 68 and 168 respectively. The reverse translational movement of the rotate cams acting through cam following tab 88 and cam follower 90, forces rack tab 114 and rack 120 with rack teeth 124 in engagement with pinion 128 to reverse its rotation and return the head 16 through four increments of rotate in the opposite direction from which it had originally been displaced. Likewise as the tilt cam is completing its rotation, the homing pin 180 engages slot 170 or groove 170 and retains the tilt cam in its home position. As the tilt cam is returned to its home position, cam follower tab 186 is forced to the right as observed in Figure 8 thus rotating cam follower bell crank 188 in the opposite direction to which it had previously been rotated and extending tilt link 198 in a downward direction. The downward direction corresponds in Figure 9 to an up and -to the right motion thus returning printhead 16 and tilt ring 200 to its home or zero tilt position. As this time the detent member 208 remains out of teeth 206 and detent member 218 and detent surface 220 remain out of engagement with the detenting teeth on the periphery of the lower edge of typehead 16.

A typehead carrying 96 characters 1 in four rows will of necessity have 24 columns of characters. The 24 columns of characters are divided into upper and . lower case of LE9-72-032 12 columns each. In each case, there have been designated for the sake of reference a zero row arid six rows of negative or minus rotation and five rows of positive or plus rotation.

In the event that the letter lower case "s" is selected, its position on the typehead is such as to require a two increment tilt, the same as the lower case "r" used in the immediate preceding example. The lower case "s" also requires four units of rotate but unlike the lower case "r" used above, the lower case "s" requires four units of plus rotate as opposed to four units of minus rotate. .

With respect to the operation of the tilt bell crank cam follower 188, tilt link 198, tilt ring 200, and detenting 206, 208, 218, and 220 of the typehead, the operation is exactly identical in both cases and will not be repeated here. 1 , However, with respect to the rotate function, inasmuch as there are only six units of rotate provided for in the rotate cam 68, it is necessary to reverse the rotation of the typehead. 16 in response to an additional signal.

A signal indicating a positive rotate is derived from the logic block 28 in the form of a rack switch signal. The rack switch pulse is a direct output of the logic block 28 to a rack switch bellows assembly 133. As part of the pneumatic or other equivalent inputs to the print carrier, a pneumatic pulse is received through input conduit 144 through bellows block 142 into chamber 146. Distendable diaphragm 148 is forced to balloon outward, from chamber 14,6 thus forcing bellows member 150, Figure 9, to pivot around its pivot point 152. Rack switch bellows tab 140 being part of bellows member 150, is forced downward and engages rack tab 136 The force exerted by the pneumatic pulse introduced to rack switcli bellows 138, forces rack tab 136 downward rotating rack 120 about pivot • I .. . shaft 122. The effect is to disengage, rack teeth 124 from the teeth of pinion 128 and simultaneously to engage rack teeth 126 with pinion 128. The effect of this is to create a reverse rotation to that described previously with the same translational direction of rack 120. As cam follower tab 188 is forced laterally by the rotation of cam 68 and its lateral displacement due to a selector pin 60 being dropped in the four unit groove 74, rack 120 is translated laterally four units of rotation displacement, by the forces exerted on rack tab 114 by cam follower 90. During the period of dwell during the rotation of cam 68, printing occurs after detenting of the type element 16 as previously described. After printing, the typehead and tilt ring are released by their appropriate detents 218, 208 and the tilt and rotate cams 168, 68 are cammed back to their home position. Upon return to their home position and during the final phases of rotation, cam lobe 77 illustrated in Figures 13 and 14 is presented to follower arm 166. As follower arm 166 is engaged by cam lobe 77, it is rotated about shaft 110 in a counterclockwise LE9-72-032 , direction as viewed in Figure 9 . The effect of this is . to rotate rocker 162 and spring 160 in a movement counter- clockwise and concentric to shaft 110 . As spring 160 is rotated counterclockwise it engages the lower portion of the rack 120 approximately directly below rack teeth 124 . As a result of this force, rack 1 20 is shifted such that rack teeth 124 again engage pinion 128 . This operation is accomplished upon the return to home position of rotate cam 68 after any operation of the print carrier which places the rack 120 in what has been referred to a plus rotation configuration. The plus rotation. configuration is anytime that rack teeth 126 are engaged with pinion 128 . Thus at the completion of any print cycle, the bifurcated rack 120 is restored to a negative rotation mode prior to the initiation of any subsequent print cycle...

In both of the above examples,, the rotation of the ' 'print and tilt cams 68 , 168 toward their home position after completing all translatory motion, causes blade 64 of selector pin 60 engaged with both grooves 74 and 1 72 of the rotate cam 68 and tilt cam 168 respectively, to follow the profile of the cam illustrated as cam profile 102 in Figures 10 and 11 . The effect of the radial cam rise on these profiles is to force selector pin 60 radially away from the axis of the rotate cam 68i and tilt cam 168 .

LE9 - 72 - 032 Upon sufficient forcing of said selector pins 60 radially away from said axis, the sprin action of tension spring 52 acting on latch lever 48 will cause latch lever 48 to rotate in a counterclockwise direction about pivot point 50. This presents latching surface 54 in a position to engage latching surface 58 when blade member 64 is no longer engaged by the rise 102 of either cam 68 or 168.

This immediately above described sequence effectively resets. each and every latch pin 60 upon the completion of each rotation of the tilt 168 and rotate 68 cams .

For the selection of a zero rotate character the zero select pin 92 remains in groove 70 resulting in no lateral translation of the rotate cam 68 and hence no rotation of print element 16. An analogous result occurs for the line of characters requiring no tilt for selection, with respect to zero tilt pin 180 and groove 170 Inasmuch as the entire selection process and all the selection apparatus is contained within the print carrier, and the only inputs to the print carrier controlling the operation of the selection apparatus , is the pneumatic or electromagentic signals transmitted thereto and the rotational forces transmitted to the print sleeve 230 through the rotation of pyint shaft 232, the carrier must have provisions for a case shift operation. To accomplish a case shift, a case shift key is depressed upon the keyboard which in turn generates signals by means of the keyboard signal generator 26. These signals are transmitted to the logic block 28 which processes the input signals and provides output signals which can be used to effectuate a case shift operation. The necessary signals outputed to the selector pin 60 corresponding and related to groove 76 of rotate cam 68. Additionally, there is required a dead-key output, a no-print output, and a rack switch output all from the logic block 28. The six unit rotate signal is the only one sent directly to the acutator block which in turn activates the latch member 48 as previously described above with respect to the printing operations and allows selector pin 60 and selector pin blade 64 to engage groove 76 of cam 68. Referring now to Figure 8, no-print actuator 318 is pressurized with the no-print pulse through input orifice 322. This extends plunger 320 thus engaging the side of escapement link 310.

Escapement link 310 is displaced leftward as viewed in Figure 8 due to a relatively loose connection at 308.

As escapement link 310 is moved by the extension of plunger 320, a leaf spring 317 against which 310 is abutting, is allowed to . flex when escapement link 310 is pushed leftward and trap escapement link 310 in its displaced position for one cycle. As the escapement link is moved in response to the rotation of escapement cam 300, the link is retracted and the shoulder of escapement link 310 is withdrawn from the proximity of leaf spring 317 and the influence of biasing spring 309 which interconnects pscapement link 310 and carrier frame 192, restores link 310 to its normal position ready for engagement with i ■ ■ i · : -1 ■ ' LE9-72-032 escapement pawl tab 316. When escapement link 310. is displaced laterally and trapped by leaf spring 317' the depending tab 314 of escapement link 310 is moved out of engagement with the escapement pawl tab 316. Thus an reciprocatory motion of link 310 in response to the rotation of escapement cam 300 is ineffective and results in a non-escaping condition. Tlxis condition is referred to a dead key notwithstanding the fact that there may not be a printing operation at the time that actuator 318 is pressurized. With the receipt of a signal pulse from logic block 28 directed to the actuator 318, the escapement is disabled for the next succeeding rotation of the print shaft 232. Λ no-print signal is also outputed from the logic block 28 as a result of the depression of the case shift key. The no-print signal is. transmitted to no-print actuator 270 in Figure 7, extending plunger 268 into engaging surface 266 of pawl 264. Due to the formation of pawl 264 as better illustrated in Figure 8, pawl 274 is acted upon simultaneously. Pawls 264. and 274 are rotated about pivot point 275 thus withdrawing their effective surfaces 264', 274' from the corresponding sur-faces of slide 262. Slide 262 then acting under the influence of spring 278 slides leftward. The sliding left-ward of pawl 278 shifts print cam follower wheel 256 left-ward by means of it being trapped between, wheel tabs 282. Inasmuch as all stops are withdrawn from engagement with slider 262 the slider 262 travels its full travel leftward LE9-72-032 -4 - thus movin follower wheel 256 out from under cam 258 thereby breaking the mechanical connection between the two. Any rotation of cam 258 would then be ineffective to produce ; a print operation.

Simultaneously with the outputing from the logic block 28 of the dead-key and no-print signals is an outputing of a signal to the "pneumatic bellows or equivalent actuator 138 for activation of the rack switch function. By switching the rack 120 from its normally minus rotate condition to the plus rotate condition coupled previously with the six units of rotate previously selected by the actuator block 30, a one quarter revolution of the typehead will be accomplished during the rise to the dwell of groove 76 of rotate cam 68. As discussed earlier, character columns on the typehead 16 are designated as zero and plus one through five and minus one through six.

This provides the capability of accessing any one of twelve character columns on one half or one case of the type element 16. It will be noted that there is no plus six character selection. Inasmuch as the carrier 10 structure is capable of a plus six selection, plus six selection is reserved for case shift operations. Upon the initiating of the no print operation, the dead key operation, the rack switch operation, and the release of selector pin 60 into rotate cam 68, selection groove 76, the carrier is conditioned for the beginning of a case shift operation.

LE9-72-032 As the print shaft 232 rotates and the rotary motion of it transmitted through print sleeve 230 and gear train 234, 236, 238 to shaft 82, the rotary/lateral translation of rotate cam 68 is the same as under any other condition where there is a six unit rotate selected by the engagement of selector pin 60 and blade portion 64 with groove 76.

As cam 68 is translated to its extreme. most position, corresponding to six units of rotate, cam lobe 79 illus-trated in Figure 12, is presented to cam follower 164 as illustrated in Figure 18. Cam lobe 79 is positioned with respect to cam follower 164 and the lateral translation dwell of groove 76, to engage follower 164 and cause it to rotate, about shaft 110 at a time when there is zero lateral translation of cam 68. The rotation of cam follower 164 about shaft 110, rocks member 162 and hence leaf spring 160 around shaft 110 also. The rotation of spring 160 about an axis through the center of shaft 110 will shift rack 120 from the plus rotate condition to the minus rotate condition as was previously discussed with respect to restoring rack 120 to its LE9-72-032 ' . . · ' ' .·" ' . . minus rotate condition after a plus selection. The effect of. shifting the rack at a time when it has been moved half way through a complete selection cycle is to provide the additive effect of the traverse and return portions of movement of cam: 68. Referring to Figure 18, if rack teeth 126 are engaged with pinion 128 during the translation of the rack, the rotation of pinion 128 and lower ball socket shaft 130 will be in a counterclockwise direction. When the rack .120 is shifted to engage rack teeth 124 with the pinion ; at the fartherest displaced point of the translation of rack 120, the return to home position of cam 68 carrying with it the cam follower linkages and rack 120, will result in further motion in a counterclockwise direction of pinion 128 and 130. Inasmuch as the two zero rotate rows on the typehead are located twelve increments of rotate apart on the periphery of the typehead 16, the compound, additive effect of counterclockwise rotation during both the traversing and the returning of., cam 68 results in twelve increments of rotation thus presenting the home row in the opposite case at the completion of the cycle.

The switching of the rack at midcycle and the change of dead key and no-print function, all alter the normal response of their respective apparatuses to yield a different result. The combined result is a case shift of the typehead.

The other functions of the selector 1 pins 60 and restoration thereof are identical to that discussed above.

During the final stages of rotation of print shaft 232 cam 28Γ engages stud 284 on restore arm 280. The force exerted on stud 284 and transmitted through arm 280 moves slide 262 to the right as illustrated in Figure 7. The moving of slide 262 toward the right against the force of spring 278, repositions print cam follower wheel 256 again under print cam 258. The rightward motion of 262 in a 'restore direction, also allows re-engagement of pawl 274 with slide. 262 thereby holding it in its fully restored position. Likewise the rotation of shaft 232 activates escapement cam follower wheel and cam follower 302 by the rotation of escapement cam 300 to pull escapement link 310 toward print shaft 232 and against the biasing action of spring 309. The motion of link 310 described immediately above allows the restoration of link 310 against plunger 320 and thus re-engages depending tab 314 with escapement pawl tab 316. At the completion of the rotation of print shaft 232, the no -print function has been activated and restored, the dead- key or non-escape has been activated, functioned, and restored, the selection of six units of rotate and the switching of rack 120 at the high dwell portion of groove 76 of rotate cam 68, has resulted in a cumulative effect of twelve units of rotate, and the selection pin has been restored. As the carrier is now conditioned, it is ready to select in a rotate and tilt fashion as described above, and the effect will be an upper case character.

An alternate embodiment for the pin selection ' technique is illustrated in a Figure 19 and Figure 21.. Referring to Figure 19, a branched channel barrel cam 400 is substituted for the barrel cam 68 in the above described embodiments. To accomplish the translational movement of barrel cam 400 with respect to its driving shaft, analogous to the translation of barrel cam 68 with respect to keyed shaft 82, a single selector pin 402 is provided for engagement with barrel cam 400. Selector pin 402 is mounted for reciprocatory motion in mounting bracket 404.

Pin 402 has a stop shoulder 406 forming the rear extension of 402. Stop shoulder 406 is engaged on the rear surface area 408 by a compression spring 410. Compression spring 410 is trapped between Pivotally mounted at pin 414 are depth control levers 416, 418 and 420. Lever 416 and 418 are . " coupled throug interlocking surfaces 422 and 424.

Lever 418 and 420 are interlocked for synchronized motion by interfering surfaces 426 and 428. Depth control lever 416 is configured such that its control surface 428 is equal to one depth increment of insertion of pin 402 into barrel cam '400. Lever 418 is configured with a two-step control surface 430 and 432. Lever 420 is the three-unit control lever and is configured with a three-step control surface 434, 436 and 438.

In order to activate selected ones of the depth control levers 416, 418 and 420, actuators 440 , . 442, and 444 are positioned under lever 416, 418 and 420 for selective engagements therewith. To provide a restore force, leaf spring 446 is provided with leaves engaging levers 416, 418, and 420 respectively. To insure the appropriate maximum mo\rement of levers 416, 418 and 420, a stop member 448 is provided to block excessive travel of the. levers respectively.

Additionally, mounted on frame or support member 404, a restore follower and crank 450 is pivotally mounted on pivot pin 452. Crank 450 has a restore surface 454 engaging the stop shoulder 406. The follower 450 is in cam following engagement with restore cam 456 for interaction therewith.

On the receipt from the logic unit 28 of signals ; y. representing the rotate requirements for. a particular character, actuators 440 , 442 and 444, which in this enbodiment are alternate embodiments of the actuator block 30 and rotate latches disclosed above in the primary configuration, are selectively activated. For a 1 , 2 , or 3 unit rotate, the appropriate actuator 440, 442 or 444 is caused to actuate, thus rotating the corresponding depth control lever 416, 418, or 420 around pin 414. As an example, if a particular letter requires a two unit rotate, the cam 400 is configured such that an insertion of selector pin 402 into the cam grove of cam 400 to a depth of 2 increments will cause a two unit rotate. The rotate mechanism for this embodiment is. substantially.-the" ί . ■ · ■· ' '. ... · Jame as that illustrated in Figure 18 and discussed earlier. The only major departure will be that the cam 400 will produce both + or - rotate conditions with one setting of the rack and will require a switching of the rack 120 to accomplish the complimentary displacement for the same groove. Thus for a two unit rotate, regardless of which direction is desired, the depth selector lever 418 corresponding to a tv/o unit insertion is pivoted about pivot point 414.

Due to the interference between surfaces 426 and 428, lever 420 is likewise rotated in the same direction around pivot point 414. The effect is. to. withdraw stop surface 438 and 436 from engagement .from stop shoulder 406. This allows stop shoulder '406 to engage.'surface 434. This surface 434 is configured, together with all other stop surf ces on the three depth control levers, to correspond to. multiples of single increments of depth insertion for selector pin 402.

For a one unit depth insertion of selector pin 402, the same procedure occurs with respect to lever 416 except that interfering surfaces 422 and 424 move lever 418 a one unit increment which in turn pivots lever 420 one unit to allow stop shoulder 406 to engage surface 436. Thus, it can be seen that through the one way interferences between levers 416 and 418 and levers 418 and 420, the actuation of one actuator 440 , 442 or 444, will insert pin 402 to the desired depth of 1, 2 or 3 increments into the groove of barrel cam 400. For increments of 4, 5 and 6 units of insertion, che appropriate additives affects of actuator 440 and 444 for a 4 unit insertion, 442 and 444 for a 5 unit insertion insertion may be affected. The affect of activating actuator 440 and 444 for a 4 unit insertion moves lever 420 around pivot 414 to completely ^ withdraw all three of its stop surfaces from potential engagement with stop shoulder 406. The activation of activator 440 rotates lever 416 and lever 418 around, pivot 414 as. discussed above such that surface 430 acts to engage stop shoulder 404. The net effect of this selection gives a 4 unit increment of insertion of pin 402.

Analogously, the activation of activator 442 and 444 will withdraw the stop surfaces of both these levers from potential engagement from stop shoulder 406 thus allowing stop shoulder 406 to engage surface 428 corresponding to 5 units or increments of insertion.

The. simultaneous actuation of all three activators 440, 442 and 444 allow stop shoulder 406 to be inserted to the maximum depth or 6 units corresponding to a 6 unit rotate. After any selection has occurred, the rotation of print shaft 232' which, in turn, drives restore cam 456 to remove the high lobe from physical force engagement with follower 450, spring 458 tensioned to frame member 404 acts to pivot restore surface 454 about pivot 452 thus acting to restore stop leaf spring 446 acting ' through its three fingers to restore levers 416, 418 and 420 to their nominal non-selected positions. Referring to Figure.21, selector pin 402 may be inserted into cam groove 460 b the activation of any or all of selector levers 416 , 418 or 420.

The depth of the insertion will control which of the branches of groove 460 pin 402 will follow. For ease in unders tanding , the depth increment of insertion and the relative amount of trans lational displacement of cam 400 along its shaft will be. designated by the units digit of the reference numeral corresponding to the cam groove. Thus , · cam groove 460 extends in a straight line from the bottom to the top of the diagram of cam 400 in Figure 21. Cam groove 461 branching to the right corresponds to one unit of rotational typehead 16. It. also requires one increment of depth insertion or the actuation of a movement of depth selector lever 416. Inasmuch as the pin is inserted, one additional increment in depth into cam 400, it will interfer with the surface designated 461' thus diverting the pin out of track 460 into track 461. Inasmuch 'i as pin 402 is held fixed spacially, and cam 400 is relatively free to translate axially, cam 400 will ' shift laterally in response to the diversion of cam 402 into track 461. Similarly, a two unit insertion will engage surface 462', and 3, 4, 5 and 6 unit insertions will engage surfaces 463', 464', 465' and 466', respectively.

Follower slot 470· or follower groove .470 will engage follower tab 88 or a similar tab to cause rotational movement of the movement conversion and transmission mechanism for converting the lateral motion of cam 400 to a rotary motion of typehead 16. As the cam 400 rotates past pin 402, all tracks 460 through 466 rise radially from the axis of the cam to a .uniform depth helping to restore follower pin 402 to its non-selected position and, at the same time, ease the re-entry of pin 402 into groove 460 if it has been diverted by an adequate insertion depth.

In the event that the pin is not inserted to a depth which would cause engagement with any of. the surfaces for diverting the pin out of track . 460, the pin will tend to remain in track 460 inasmuch as there are no other lateral forces acting on the cam to divert it with respect to pin 402.

The change of direction of rotate and the accomplishment of character case shift is accomplished 1 analogously to the procedure described with respect 2 to the rotate cam 68 above. 3 The release of the case shift key on the keyboard 4 18 will have the effect of creating signals from 5 the keyboard signal generator 26 calling for an 6 additional case shift. The entire sequence will 7 then be initiated and completed resulting in the plus 8 rotation of the head 16 through twelve additional 9 units of rotation thus repositioning the head at 10 the lower case position. While the head 16 is in 11 the upper case position, the selection comprising 12 the rotating and tilting of the character matrix 13 on the printhead 16 is identical to that of a lower 14 case selection previously described. 15 It should be recognized that although the selection 16 apparatus is disclosed and described with respect to 17 a 96 character print element, it may, by redimens iojiing 18 of the positions of the cam surfaces, modify the device 19 to accept. n 88 character element with equal application. 20 While generally the invention has been described El using pneumatic control signals, it should be readily 22 recognized that the substitution of electromagnetic 23 controls, in lieu of the pneumatic controls may also 2 be implemented quite simply by one of ordinary skill 25 in the art. Further, alternative techniques for changing LE9-72-032 of the linear motion of the cam to a rotary motion of the typehead can be implemented. Such techniques would involve Geneva gear type mechanisms or reverse Geneva gear such as pins engaged in grooves in the top of a rack member and other well-known equivalent linear to rotary conversion techniques. . .

While the invention^ has bee particularly shown, 8 and described with reference to preferred embodiments 9 thereof, it will be understood by those skilled in the 10 art that the foregoing and other changes in form and 11 details may be made therein without departing from the 12 spirit and scope of the invention. 13 I claim: LE9-72-032

Claims (6)

44924/2 _^ CLAIMS:

1. Selection mechanism for a printer of the single element type, having a single print element carried by a print carrier, wherein for character selection the print element performs rotating and tilting motions, characterized by at least one rotational barrel cam mounted for axial displacement, and having a plurality of grooves cut into its surface, the shape of said grooves individually corresponding to different numbers of units of rotation and/or tilting of the print element by selectively controllable first cam followers mounted for engagement of said grooves, and upon rotation of said cam causing axial displacement thereof corresponding to the shape of said grooves; and by first means for converting said axial displacement of said cam into a rotative motion of selectable direction of said print element, and second means for converting said, axial displacement of said cam into a tilting movement of said print element.

2. Mechanism according to claim 1, wherein said first means for converting said cam motio comprise a pinion rigidly connected to said print element, and a toothed rack having two rack portions, said rack being switenable by a switching mechanism such that only one of its rack portions at a time is in engagement with said pinion causing the pinion to be driven into one or the opposite direction, characterized in that said rack switching mechanism comprises an air chamber which is closed by a membrane connected to a pivotable bellows member, and that with said switching mechanism being i its actuated state, said double rack is kept switched from its normal position, defined by a spring, by means of a linkage in its actuated position. 44924/2

3. Mechanism according to claim 2, characterized in that means are provided for resetting said double rack into its normal position, said means comprising second cam followers engaging grooves cut into said cam, said grooves having a profile such that said cam followers upon completion of one revolution of said cam perform an upward movement such that said rack is switched by means of a rocker and a spring.

4. . Mechanism according to claim 1, characterized in that said cam has a groove cut therein for engagement by a cam follower tab which is connected to a tilting device of said print element by means of a linkage so as to permit transmission of the tilting units determined by the shape of said grooves onto the print element upon axial displacement of said cam.

5. Mechanism according to claim 1, characterized in that said cam followers are designed so as to be controllable by pneumatical means.

6. Mechanism according to claim 1, characterized in that for performing each of said rotative and tilting motions of said print element respectively one individual cam is provided, said two cams being coaxially and slideably mounted for rotatio on a common shaft. For the Applicants ARTNERS