US3103272A

US3103272A - Power action for typewriter

Info

Publication number: US3103272A
Application number: US838894A
Authority: US
Inventors: Edwin O Roggenstein
Original assignee: Sperry Rand Corp
Current assignee: Sperry Corp
Priority date: 1959-09-09
Filing date: 1959-09-09
Publication date: 1963-09-10
Anticipated expiration: 1980-09-10
Also published as: DE1222084B; CH395149A; NL107252C; FR1265770A

Description

p 10, 1963 E. o. ROGGENSTEIN 3,103,272

POWER ACTION FOR TYPEWRITER 4 Sheets-Sheet 2 Filed Sept. 9, 1959 INVENTOR. [0 WW 0. mam saw P 10, 19.63 E. o. ROGGENSTEJN 3,103,272

POWER ACTION FOR TYPEWRITER 4 Sheets-Sheet 3 Filed Sept. 9, 1959 II I IIIIIIIIIII I Sept- 10, 6 E. o. noeeaus'rsm 3,103,272 POWER ACTION FOR TYPEWRITER Filed Sept- 9, 1959 4 ShOBtS-SIIBBT- 4 1'5 ,0 52 H68 9? 5a 67" i; if

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INVENTOR. [fl/V/A a 190562-7167?! Arfaewrr United States Patent Ofiicc 3,163,272 Patented Sept. 10, 1963 3,103,272 POWER ACTION FOR TYPEWRITER Edwin 0. Roggenstein, Stamford, Conn., assignor to Sperry Rand Corporation, New York, N.Y., a corporation of Delaware Filed Sept. 9, 1959, Ser. No. 838,894 19 Claims. (Cl. 197-17) This invention relates to writing machines and in particular to an improved power action as embodied in a portable typewriter.

A particular object of the invention is to provide a reliable and inexpensive power action for typewriters and the like utilizing a power driven snatch roll which, unlike conventional snatch roll drives, permits smooth and uniform type bar acceleration and provides simple and novel means for both individual and over-all type impression control without the need of changing the speed of the power roll.

A further object of the invention is to provide for repeat operation of one or more of the key lever actions by utilizing the basic elements employed for a single key action without the need for adding parts.

Still further objects of the invention are to provide a parallel key action that makes possible a uniform action for the means operated by each key that controls the operation of the power action; to provide a novel housing tube in which the power roll can be mounted and which tube can be adjusted to provide a timing control for the operation of the parts; to provide a combination power action and keyboard that can be taken out of the main frame of the machine for ready replacement or adjustment of the parts; and to provide a novel form of repeat means that does not require the addition of a number of parts over those required for single printing action.

Other objects and structural details of the invention will be apparent from the following description, when read in conjunction with the accompanying drawings wherein:

FIGURE 1 is a front to rear view in sectional elevation of the major portion of a key mechanism and power action unit of a portable electric typewriter con struction,

FIGURE 2 is a view of the power action shown in FIGURE 1 at the first or trip-off stage of movement,

FIGURE 3 is a view similar to FIGURE 2 showing the pawl in full engagement with the power roll,

FIGURE 4 is a view similar to FIGURE 3 showing, in addition, type bar operating means at the maximum throw afforded by operation of the power action,

FIGURE 5 is a view showing the action following that depicted in FIGURE 4 with the operating pawl fully disengaged from the power roll,

FIGURE 6 is a view similar to FIGURE 1 showing the position of the mechanism when printing takes place,

FIGURE 7 is a view similar to FIGURE 2 showing the power action in position for repeat printing,

FIGURE 8 is a longitudinal view of the power action shaft, partly in section, and taken substantially on the line 8-8 of FIGURE 1,

FIGURE 9 is a section taken on the line 9-9 of FIG- URE 8 showing the printing impression control means,

FIGURE 10 is a section taken on the line 10-40 of FIGURE 8 showing a ribbon vibrating control means.

FIGURE 11 is a fragmentary section showing one key lever and a repeat control means associated therewith,

FIGURE 12 is a section taken on the line 1212 of FIGURE 6 showing the key guide in which the repeat control means is mounted,

FIGURE 13 is an enlarged section on the line 13-13 of FIGURE 11 illustrating the repeat control means used in the key guide,

FIGURE 14 is a view of a portion of a power action means showing the means of securing thereto one end of an operating link, and

FIGURE 15 is an edge sectional view on the line 1515 of FIGURE 14, showing the parts of FY- URE 14.

Referring to the drawings in detail and in particular to FIGURE 1, 10 indicates a parallel keyboard action and a power roll assembly 11 in a single unit which includes a power mechanism inner frame 12 having side walls 13 which are secured in any suitable manner as at 14 to the sides 16 of an outer or main frame 17. The keyboard action 10 includes a bank of keys 18 each having a key lever 19, shaped to provide a portion 21 passing through a guide comb 22, a downwardly depending stem 23, an arm portion 24 extending rearwardly for passage through an inner guide comb 26, and a downwardly directed terminal portion 27 to which is pivoted as at 28 a trip latch 29 to be later referred to. The stem 23 and the arm 24 of each key lever are pivotally connected through the medium of upper and lower parallel links 31 and 32 respectively, with mounting rods 33 and 34 extending thr-u slotted support 33-a and 34-a respectively, supported between the side walls 13 of the inner frame 12. The keys 18 are each yieldably held in raised position by a spring 36 connecting each arm 24 with a channel member 37 along the lower edge of which said inner guide comb 26 is formed and in which is provided a butler strip 38, of any suitable material, common to all of the key levers.

The type bar assembly 39 consists of the usual arcuate array of type bars 41 mounted on a pivot rod 42 passing through a slotted segment 43, the latter of which can be raised and lowered for case shift by suitable lever means in the well known manner and which, along with an escapement controlled carriage for the platen 44, it is not deemed necessary to show. The segment 43 is provided with a universal bar 46 for engagement by a heel 47 on each type bar 41 for actuating an escapement release member 48. The assembly 39 also includes the ribbon carrier 49 and its vibrator arm 51.

Each type bar it is connected by a tie rod 52 with one arm 53 of a type bar bell crank 54 which is mounted on a pivot rod 56 passing through the slotted portion of a comb bar 57 supported in the opposite side walls of the frame 16.

Another arm 58 of the bell crank 54 is connected by a link 59 to a stud 61 on a power action ring or annulus 62, one of the latter of which is provided for each key lever 19 that controls the operation of the power roll assembly 11. Each power action ring 62, as can be seen best in FIGURES 2 and 8, is shaped to provide a bushing or hub portion 63 presenting a continuous flange 64 and a collar 66 at opposite sides of the ring so that when the rings 62 are assembled on a support tube 67, as shown in FlGURE 8, the hubs 63 act as spacers for the radially extending body portions or fins 68 of the rings 62. The collar 66 of each hub portion 63 is interrupted to provide an arcuate opening 69 which is arranged to register with a similar arcuate slot 71 in the support tube 67, upon which the rings 62 are mounted for turning movement, there being a slot 71 for each power arm ring 62. The latter is preferably made of plastic or any other suitable material and is formed with said outwardly directed fin 63 presenting an eye tab 72 at one end which is connected by a tension spring 73 to a cross plate 74 to yieldably maintain each power arm ring 62 at a home position with the tab 72 abutting a stop strip 76 out he cross plate 74-. The opposite end of the Pin 68 is divided to present prongs 77 and 78. The prong 77 bears against a ribbon vibrator bail 79, FIGURES 8 and 10, which bail extends substantially lengthwise of the support tube 67 and is carried by the feet 81 of spaced bands 82 mounted for rotation on the support tube 67.

When a character key 18 is operated, the corresponding power action ring 62 will be turned or rotated, as will be later explained, and will cause the prong 77 to rotate the ball 79' and a support band 82 to pull on a link 83 to rotate a shaft 8 suitably mounted so that a ribbon feed arm 86 is swung clockwise to operate a ribbon feed exemplified by part of a member 87, further illustration of which is deemed unnecessary. When the shaft 84 rotates, it also throws an arm 88 clockwise to push on a ribbon vibrator link 89 to swing a ribbon vibrator control strip 91 and rock a shaft 92 secured thereto. From the usual ribbon adjustment, found adjacent the keyboard of most typewriters, the position of the link 89 can be adjusted through linkage 90 so that a pin 93 on the end of said link 89, adjustable in an open sided slot 94 of strip 91, can cause the ribbon to be moved for red or black printing or silenced for stencil work, the position of the parts depicted in FIGURE causing oscillation of the vibrator arm 51 and ribbon carrier 49 to print through the black portion of the ribbon.

The other prong 78 of the fin 68, as shown in FIGURE 6, is adapted to engage a printing impression control spring 96 or energy absorbing device the tension of which may be waried by an adjusting screw 97. This printing impression control is common to all of the power action rings 62 but is individually adjustable so that the amount of driven movement or force of impact of each type bar can be closely controlled. Each type bar is driven by the action of a power roll 98 which, as shown in FIG- URE 8, is journalled at its ends 99 in bearings 101 carried by the side Walls 13 of the inner frame 12 and driven by a pulley 102, a drive belt 103 for which transfers the power from a suitable motor driven pulley 104 as shown in outline in FIGURE 1. The power roll 98, shaped to provide longitudinal spline ways forming teeth 106, is housed in the tube 67 which is supported for turning movement on the bearings 101 and is arranged to be turned, as shown in FIGURE 9, by a trunnion disk 107. The latter has opposed tabs 108 fitting into side openings 109 in the tube 67 and an arm 111 which, through a rod 112, is connected to a finger lever 113 yieldably held adjacent the keyboard at any position of adjustment by a detent strip 114. The lever 113 and its associated parts constitute a common printing impression control by adjusting the tube 67 so that the slots 71 thereof determine the limit of driving movement imparted to the power rings 62 by the power roll 98.

The fin 68 of each power action ring 62 has a stud 61 passing therethrough to which, at one side of the fin, is connected the lower end of the link 59 which, as seen in FIGURES 14 and 15, is detacha bly secured in place on the stud 61 by a spring clip 117. The stud 61, at the opposite side of the fin 68, provides a pivot for a pawl carrier 118, FIGURE 2, shaped to provide a detent shoulder 119 at its upper end and at its lower forked end, spaced

prongs

121 and 122 against the latter of of which is yieldably maintained a pawl stud 123 secured in the tail 124 of a pawl 126 pivoted as at 127 to the pawl carrier 118.

The nose 128 of the pawl 126 protrudes through the opening 69 in the ring 62 and through a coinciding slot 71 in the tube 67 as shown in FIGURE 1 when the parts are in nonoperating position as determined by the position of a trigger 129. The latter is pivoted as at 131 to the fin and has an upper ledge portion 132 and a trigger arm 133 underlying the trip latch 29 which is shaped to provide toe and

shoulder portions

134 and 136, respectively, on the lower end thereof. The upper edge of the trip latch 29 is provided with an arcuate channel 137 in which a limit pin 138, in the terminal portion 27 of the key lever arm 24, rides to limit the swinging move- 4 ment of the trip latch 29, about its pivot 28, by abutting stop projections 139 bounding said channel 137.

Each trip latch 29 is provided with a nose which underlies the top edge of a latch control channel 140 for maintaining the latch 29 in vertical normal position with the toe 134 over the trigger arm 133 as shown in FIGURE 1. The pawl carrier 118 is provided with a cut out or seat 141 which serves as a stop for the pawl stud 123 as it is driven thereinto by a spring 142 which yieldably resists swinging movement of the trigger 29 and acts as a reset means therefor as will be presently explained.

As illustrated in FIGURES 1, 11, 12 and 13 a portion of each character key is guided in a guide comb 22 to be limited in downward movement by a strip of rubber 143 or other composition having elastic properties. In this machine ordinary pressure on the keys will depress the key levers to cause one printing operation and in order to cause repeat" printing operation, the strip 143 at selected places beneath certain key levers such as for an asterisk or period, is provided with a cavity 144 in the under side thereof which provides a yieldable bridge portion 146 so that the operator, in order to bring about repeat operation, will have to intentionally bear down on the key to lower it against the resistance afforded by the bridge portion 146 which will yield by being distorted downwardly into the cavity 144. The bridge 146 is sufficiently resistant to permit regular single imprint typing and, if desired, the strip 143 can have a cavity and bridge combination for each of the keys or only for selected ones as shown. The action of the key levers for repeat" will be explained in the operation description to follow.

As seen in FIGURE 1 the springs 36 keep the key levers 19 in raised position and the engagement of the nose 135' of each trip latch 29 with the channel member 140, positions the toe portion 134 of each trip latch over the free end of the trigger 129. When a key is depressed for typing, as in FIGURE 2, the trigger leaves the detent shoulder 119 and the spring 142 swings the pawl carrier 118 clockwise about its pivot 61 to bring the nose 128 of the pawl 126 within operating range of the snatch or power roll 98. The latter as well as the power action ring 62 rotates in clockwise direction and, as seen in FIGURE 2, the initial movement or trip-oil of the parts places the nose 128 of the pawl 126 at about the center face of the engaged tooth of the power roll and as the ring 62 starts moving the top edge of the nose of the pawl comes to horizontal position to be fully engaged by the tooth of the roll as seen in FIGURE 3, to provide a full bite of the tooth and pawl, which results in a positive acceleration of the parts including operating link 59 which cause operation of the type bar.

When the pawl is fully engaged by the tooth of the power roll, it is swung to the FIGURE 3 position and as the carrier 118 has swung to its limit position with the pawl stud 123 against prong 121 the ring 62 has begun its rotation because the force of the pull of the tooth on the pawl is aligned with the stud 61 and the first pivotal movement of the pawl 126 from the FIGURE 2 to the FIGURE 3 position will only move the stud 123 into engagement with prong 121 and thereafter the turning force of the power roll will rotate the ring 62 and pull on the link 59. As the ring 62 rotates relatively to the support tube 67 the lower or under edge of the nose 128 of the pawl 126 will engage the edge of slot 71 to cam the pawl outwardly with the result that the pawl carrier will be swung outwardly toward the position shown in FIGURE 4 until the upper ledge 132 of the trigger 129 engages beneath the shoulder 119 of the pawl carrier as shown in FIGURE 5.

The lower edge of the slot 71 in the tube 67 causes the pawl in its outward movement to be disengaged from the tooth of the power roll after providing the maximum power thrust to the type bar after which the latter continues under its own momentum to the printing point. The free rising movement of the key lever 19, thru spring 36,

FIGS. 1 and 6, will restore the trip latch 29 to its starting or home position as seen in FIGURE 5.

In repeat operation, the finger of the operator will depress the key to the repeat position as permitted by the cavity 144 in the limit strip 143 and the first complete printing operation will take place as above described for the initial printing impression. During this action of first printing, in the clockwise rotation of the ring 62, FIGURE 3, the trigger 129 will strike the trip latch 29 and swing it to the FIGURE 7 position with the result that the repeat dwell or shoulder 136 at the bottom edge of the latch 29 will be so positioned that, when the ring 62 has a counterclockwise restoring movement, the arm 133 of the trigger 129 will engage the shoulder 136 and kick the ledge 132 of the trigger from beneath the detent shoulder 119 of the pawl carrier 118.

As above explained, when the first printing action of the ring is completed and the pawl is forced out of engagement with the power roll, the trigger will latch the pawl in inoperative position so that the ring can have its counterclockwise restoring movement undcr the urge of its spring 73. Thus, when the arm 133 of the trigger engages shoulder 136 it will free the pawl carrier 118 and the pawl 126 will immediately reengage the power roll 98 for a repeat operation and will continue to do so as long as the key is held down in repeat position. When the key is released the trip latch 29 will rise and in striking the channel 140 will be restored to normal position.

In FIGURE 6 the pawl 126 has been completely moved out of the range of the power roll and the momentum of the parts causes the throw of the type bar to printing contact with the platen after the drive force of the power roll 98 has been disconnected from the ring 62 by the withdrawal of the pawl carrier, the ring being interrupted in its clockwise motion by engagement of the prong 78 of the fin 68 with the individual impression adjusting spring 96. Referring to FIGURE 9, it can be seen how the engagement of the pawl 126 with the power roll can be adjusted by setting the universal or common printing impression control lever 113 as desired. This will rotate the support tube 67 to position the slots 71 therein to cause camming out of the pawl at an earlier or later time in the rotation of the power roll and hence after the actual time that driving force is applied to the rings 62.

While I have shown and described what I consider to be the best embodiment of my invention, it is obvious that changes in form could be made without departing from the spirit of the invention, and I therefore do not limit myself to the exact form herein shown and described nor to anything less than the whole of my invention as hereinbefore set forth and as hereinafter claimed.

What I claim is:

1. In a writing machine, a keyboard action, a type bar assembly, a power mechanism between the keyboard action and said type bar assembly including a power ring and a drive shaft, said ring being positively connectable with said shaft for rotative movement coaxial with said shaft, and means including a pawl member carried by said ring and engageable with a tooth of said shaft con trolled by said keyboard action for operatively connecting said power ring to said drive shaft to actuate said type bar assembly,

2. la a writing machine, a keyboard action, a type bar assembly, a power mechanism between the keyboard action and the type bar assembly including a power ring and a drive shaft, said ring being positively connectable with said shaft for rotative movement coaxial with said shaft, means detachably connecting the power mechanism directly with the type bar assembly, and means including a pawl member carried by said ring and engageable with a tooth of said shaft controlled by said keyboard action for operatively connecting the power ring to said drive shaft to actuate said type bar assembly for printing operation.

3. In a writing machine, a main frame, a type bar assembly in said main frame, an auxiliary frame, a keyboard action, a power mechanism, including a power ring and a drive shaft, said ring being positively connectable with said shaft for rotative movement coaxial with said shaft, said action and mechanism being mounted in said auxiliary frame and removable as a unit from said main frame, means detachably connecting the power mechanism directly with the type bar assembly, and means including a pawl member carried by said ring and engageable with a tooth of said shaft controlled by said keyboard action for operatively connecting the power ring to said drive shaft to actuate said type bar assembly for printing operation.

4. In a writing machine, a keyboard action, a type bar assembly, a power mechanism between the keyboard action and said type bar assembly, said power mechanism including a toothed drive shaft, a slotted tube in which said shaft rotates, power rings mounted for rotation on said tube, pawl means on each ring movable through a slot in said tube for engagement with the teeth of the drive shaft and means controlled by said keyboard action for controlling the movement of said pawl means to operatively connect said pawl means with said drive shaft for printing operation.

5. A writing machine, as set forth in claim 4, including means for rotatively adjusting said tube to change the location of said slots and control the extent of engagement of the pawl means with said drive shaft.

6. In a writing machine, a keyboard action, a type bar assembly, a power mechanism intermediate the keyboard action and said type bar assembly, said power mechanism including a toothed drive shaft, a slotted tube in which said shaft rotates, power rings mounted for turning movement on said tube, pawl means on each ring arranged to move through a slot in the tube for engagement and disengagement with the drive shaft, latch means controlled by said keyboard action for controlling the engagement of the pawl means with the drive shaft for printing operation and means on said pawl means coacting with a slot in the tube for disengaging the pawl means from operating engagement wtih said drive shaft.

7. In a writing machine, a keyboard action, a type bar assembly including operating link means, a power mechanism intermediate the keyboard action and the type bar assembly, said power mechanism including a drive shaft and a driven ring member, a stud on said member to which said operating link means is connected, a spring clip fitting over said stud for detachably retaining said operating link means in place on the stud, and means on said driven ring member controlled by the keyboard action for operatively connecting said drive shaft and said driven ring member.

8, In a writing machine, a keyboard action, a type bar unit assembly, a power mechanism between said keyboard action and the type bar unit assembly including a constantly operating toothed power roll, a slotted power ring for each type bar unit, a tube mounted for turning movement encasing said power roll and having slots coinciding with the slots of said rings and upon which tube said rings are mounted for rotary movement, pawl means on each ring arranged to move through a slot in the tube for engagement with the power roll to define an initial power driven throw for an associated type bar, the end of a slot in the tube coacting with said pawl to disengage the latter from the power roll to define a secondary free throw of said type bar, and means for yieldably resisting the movement of said ring.

9. A writing machine, as set forth in claim 4, including ribbon vibrating means and means common to said pawl means for actuating said ribbon vibrating means when the pawl means is operatively connected to the drive shaft for printing operation.

10. In a writing machine, a keyboard action including a vertically movable terminal portion for each key lever, a type bar assembly, a power mechanism between the keyboard action and said type bar assembly including a toothed drive shaft, a slotted tube in which said shaft rotates, power rings mounted for rotation on said tube and movable from a home position for operating said type bar assembly, pawl means on each ring movable through a slot of the tube to engage the teeth of the drive shaft to rotate said ring, and trigger means for holding the pawl means out of engagement with said teeth, said trigger means being normally disposed for engagement by said terminal portion of a key lever, to release the pawl means for engagement with said teeth, and a slot of said tube being arranged to disengage said pawl means from the teeth of the drive shaft to allow restoration of said trigger means to holding position and said ring to home position.

11. A writing machine, as set forth in claim 10, in which said terminal portion for each key lever includes pivoted trip latch means movable to different positions of adjustment to vary the operation of said trigger means.

12. In a writing machine, a power mechanism for operatively connectin g a keyboard action and a type bar assembly comprising a driven shaft having spline ways providing teeth lengthwise of said shaft, a slotted tube in which said shaft rotates, power rings, and pawl means on each ring movable through a slot in the tube and arranged to engage said teeth to connect the shaft and a ring and provide a unitary driving connection between the keyboard action and said type bar assembly.

13. In a writing machine, key lever means, a type bar means for each key lever means, a power mechanism intermediate the key lever means and the type bar means, said power mechanism including a toothed drive shaft, a slotted tube mounted for turning movement and in which said shaft rotates, power ring means mounted for rotation on said tube and yieldably held at a home position, each ring means being shaped to provide radially extending fin means, pawl oarrier means pivoted to said fin means, pawl means on the carrier means, trigger means for holding the pawl carrier means inoperative, means for yieldably urging the trigger means to holding position and for urging the pawl carrier means to engage the pawl means with the teeth of said shaft through said slot in the tube to turn the ring means as a unit with said shaft, means controlled by the key lever means for operating the trigger means to release said pawl carrier means, link means connecting said power ring means with said type bar means, and means for adjustably limiting the turning movement of said power ring means to alter the printing action of said type bar means.

14. A writing machine, as set forth in claim 10, in which said terminal portion for each key lever includes pivoted trip latch means movable initially to operate said trigger means from said normal disposition and movable secondly to block restoration of said trigger means to holding position to provide for a repeate operation of a power ring.

15. In a writing machine, a key lever action, a type bar assembly, a power mechanism between the key lever action and said type bar assembly including a power ring and a drive shaft, pawl means controlled by regular key lever action for operatively connecting said power ring and the drive shaft for a single printing operation and key lever controlled trip latch means movable to one position for conditioning said pawl means for a single printing operation and to another position for conditioning said pawl means for a repeat action of said power ring and said type bar assembly.

16. A writing machine, as set forth in claim 15, in which said key lever action includes guide means for the key levers of said action, stop means in said guide means common to said key levers for arresting the movement of the levers under a normal operating finger pressure and cavity means in said stop means providing bridging means for depression by said levers when the latter are subjected to an increased operating finger pressure.

17. A writing machine, as set forth in claim 13, in which the means controlled by the key lever means for ope-rating the trigger means includes a trip latch pivoted to the key lever means, which latch is disposed adjacent to said trigger means and presents toe and shoulder portions for contact with said trigger means at different pivotal positions, and control means for automatically setting said latch after a trigger openating movement.

18. A writing machine, as set forth in claim 6, including spaced band means mounted for turning movement on said tube, a bail connecting said band means and common to said power rings, ribbon control means operated by said band means, and means on said power rings for engagement with said bail.

19. A writing machine, as set forth in claim 12, in which said pawl means includes a pawl carrier pivoted to each power ring, a pawl pivoted to the carrier, the pivots of said carrier and pawl bein g substantially aligned for rin-g turning movement, a seat portion in said carrier, a stud on the pawl for movement in said seat portion, and means for yieldably resisting said pawl movement for providing an initial movement of acceleration for the ring in its power operation.

References Cited in the file of this patent UNITED STATES PATENTS 1,480,698 Shiek Jan. 15, 1924 2,043,393 Pasinski June 9, 1936 2,158,066 Evans May 16, 1939 2,254,764 Yaeger Sept. 2, 1941 2,723,740 Toeppen Nov. 15, 1955 2,902,131 Ascoli et al. Sept. 1, 1959 FOREIGN PATENTS 439,152 Germany Jan. 6, 1927

Claims

1. IN A WRITING MACHINE, A KEYBOARD ACTION, A TYPE BAR ASSEMBLY, A POWER MECHANISM BETWEEN THE KEYBOARD ACTION AND SAID TYPE BAR ASSEMBLY INCLUDING A POWER RING AND A DRIVE SHAFT, SAID RING BEING POSITIVELY CONNECTABLE WITH SAID SHAFT FOR ROTATIVE MOVEMENT COAXIAL WITH SAID SHAFT, AND MEANS INCLUDING A PAWL MEMBER CARRIED BY SAID RING AND ENGAGEABLE WITH A TOOTH OF SAID SHAFT CONTROLLED BY SAID KEYBOARD ACTION FOR OPERATIVELY CONNECTING SAID POWER RING TO SAID DRIVE SHAFT TO ACTUATE SAID TYPE BAR ASSEMBLY.