US3212616A - Space and repeat space bar mechanism for an electric typewriter - Google Patents

Description

Oct 1965 P. FRECHETTE ETAL 3,212,616

SPACE AND REPEAT SPACE BAR MECHANISM FOR AN ELECTRIC TYPEWRITER Filed June '7, 1965 INVENTORS LEO F? FRECHETTE LAB ROBERT J. IN SKI United States Patent SPACE AND REPEAT SPACE BAR MECHANISM FOR AN ELECTRIC TYPEWRITER Leo P. Frechette, Hartford, and Robert J. Slabinski, New Britain, Conn., assignors to Royal McBee Corporation,

New York, N.Y., a corporation of New York Filed June 7, 1963, Ser. No. 286,372 1 Claim. (Cl. 197-82) This invention relates to an improved space bar actuated mechanism for an electric typewriter or the like.

Mechanisms of this general nature are many and varied in the prior patented and commercial art. Their shortcomings, however, reside in one or more areas such as relatively high cost, unreliability in use, difiiculties in assembly, too nice adjustment requirements and too frequent service calls in the field. Another difficulty resides in slowness of response of the escapement mechanism to depression of the space bar. One of the principal contributing causes of these conditions lies in the complexity and plurality of parts intervening the space bar and the escapement mechanism. Obviously the more there are of such parts the more difficulty in assembly and adjustment results as these parts must be machined to narrow tolerances and must be finely adjusted if timely spacing is to be achieved with low noise output.

It is accordingly among the objects of this invention to provide a space bar mechanism comprising a substantially irreducible number of parts that need little or no adjustment and thus overcomes the above mentioned difficulties as well as others. Other objects will be in part apparent and in part pointed out hereinafter.

In the drawing wherein we have shown a preferred embodiment of the invention and wherein similar reference characters refer to similar parts in the three figures:

FIGURE 1 is a fragmentary isometric view of the mechanism;

FIGURE 2 is an elevation of the clutch and cam comprising a portion of the mechanism; and

FIGURE 3 is a detail of a double dip device for effecting repeat operation of the mechanism.

In general this mechanism comprises a conventional double dip space bar manually operable to effect single or repeat space operation of the escapement mechanism. A bell crank, fulcrumed on a cross shaft, has one arm connected to the space bar and another arm formed to provide a pair of lugs which control a wrapped spring clutch mounted on a constantly rotating drive shaft. One element of the clutch comprises a cam, the follower of which, upon engagement of the clutch drives the escapement mechanism. It should be noted that this action can as well be employed to actuate other instrumentalities in the typewriter, i.e. its application to the escapement is illustrative.

More particularly and with reference to FIGURE 1 a cross shaft is mounted on the machine frame F and pivotally supports a pair of space bar key levers 11 and 12 which are located adjacent the opposite sides of the typewriter respectively. The front ends 11a and 12a of these levers are bifurcated and embrace a crank rod 13 pivotally supported by the frame and biased clockwise by a spring 14 interconnecting the crank rod and the frame. Thus the levers 11 and 12 are constrained to move together. A space bar 15 is suitably secured to the levers and is manually depressible against the bias of spring 14. A down-stop 16 underlies feet 111) and 12b on levers 11 and 12 respectively to limit the down travel of space bar 15. An up-stop (not shown) may be provided to limit the up travel of the space bar.

Lever 11 includes a rearwardly extending arm 110 on the end of which are formed two cars 11d and He,

one above the other and lying in spaced parallel vertical planes to provide a gap 11 therebetween. A powered constantly rotating shaft 17 is suitably journalled in the machine frame and freely supports a cam 18. A wrapped spring clutch 19 (FIGURE 2) is mounted, with an interference fit, on shaft 17 and has one end 19a secured to cam 18 and a tail 19b whose movement is releasably impeded by lever ear 11d. A cam follower 20 is rockably mounted on a shaft 21 carried by the machine frame and is positioned to engage surface 18a of cam 18. One end of a link 22 is pivotally connected to follower 20, the other end of the link being connected to the typewriter escapement mechanism (not shown) or other instrumentality to be actuated.

It may now be seen that when space bar 15 is depressed lever 11 is rocked counterclockwise to lift its ear 11d out of the path of movement of clutch tail 19b permitting the clutch to engage and the tail to pass through gap 11 behind car 110. As noted above, ears 11d and 11e lie in spaced planes, hence ear He will not impede the passage of clutch tail 19b through gap 11]. Such counterclockwise movement of lever 11 also positions lever ear 11a in the path of movement of clutch tail 1% so that after one revolution of shaft 17 and cam 18, the clutch tail engages lever car 118 to effect disengagement of the clutch. Hence but a single operation of the escapement mechanism by cam 18 and follower 20 is effected.

Preferably mechanism is provided for repeat operation of the escapement mechanism without having to repeatedly depress the space bar. To this end space bar lever 11 pivotally supports a bell crank lever 23 having an arm 23a to which is connected one end of a spring 24, the other end of this spring being connected to lever 11 thus to bias the bell crank counterclockwise. Crank 23 includes a stop lug 23b which overlies and engages the top of lever 11 to limit counterclockwise movement of the bell crank. The bell crank also includes a foot 230 the sole of which normally underlies the sole of lever foot 1112. Thus when space bar 15 is depressed, foot 230 first engages down stop 16 to yieldably resist further depression of the space bar to provide a single escapement operation as described above. If repeat operation is desired, added pressure on space bar 15 will overpower spring 24 so that lever 11 will be further rocked counterclockwise sufiiciently to remove its ear 11c out of the path of movement of clutch tail 19b. Repeat operation results. Lever feet 11b and 12b and down-stop 16 limit repeat depression of space bar 15.

Thus we have provided a space and repeat space bar mechanism comprising a minimum of parts that need little or no original or subsequent adjustment lending to low cost manufacture and service-free use in the field.

Accordingly we have provided a space bar mechanism that attains the several objects set forth above in a thoroughly practical and efiicient manner.

As other embodiments of the invention are possible and as modifications of the one disclosed may be made, all without departing from the scope of the invention it is to be understood that the foregoing should be interpreted as illustrative and not in a limiting sense.

We claim:

An action for cyclically operating an instrumentality in an electric typewriter in response to depression of a key, comprising a frame,

frame mounted cross shafts,

a continuously rotating power shaft carried by said frame,

a cam freely mounted on said shaft,

a coiled spring wrapped around said shaft and having a normal diametral dimension less than said shaft diameter whereby said spring grips and is driven by said shaft, one end of said spring being bent in an axial direction and secured to said cam, the other free end of said spring being bent in a radial and axial direction,

a key lever pivotally shafts,

means biasing said key lever to normal position, said lever being depressible to first and second limits,

a frame mounted downstop,

yieldable means on said key lever adapted to engage said downstop thereby to offer resistance to key lever depression beyond said first limit, added pressure causing said means to yield to permit movement of said key lever to said second limit, said lever having a rearwardly extending arm with the end thereof bent to form first and second ears lying in spaced parallel planes, the first and rearwardrnost one of which is normally disposed to be engaged by the radially and axially extending free end of said spring thereby holding said spring coils disengaged from said shaft,

depression of said key to said first limit moving said first ear out of the path of and releasing said free spring end thereby permitting said spring to wrap and couple said shaft to said cam, and positioning said second ear to engage the free end of said spring thereby to disengage said spring and shaft after one cam revolution should said key lever remain depressed to said first limit, said second ear releasing and said first mounted on one of said cross ear engaging said free spring end upon return of said key lever to normal position,

depression of said key lever to said second limit position moving both of said ears out of the path of said free spring end to permit repeat rotation of said cam as long as said key remains depressed to said second limit,

a cam follower pivotally mounted on another of said cross shafts and rockable by said cam,

and an output link connected to said follower and to said instrumentality thereby to cycle said instrumentality each revolution of said cam.

References Cited by the Examiner UNITED STATES PATENTS 1,913,892 6/33 Mez.

2,565,985 8/51 Norton et a1 19784 X 2,714,948 8/55 Schremp et al 19717 2,723,740 11/55 Toeppen 19717 2,728,436 12/55 Kupper 19782 2,798,584 7/57 Kennedy 19717 2,879,876 3/59 Palmer et al 19716 2,902,131 9/59 Ascoli et a1 197-17 2,973,078 2/61 Templeton et a1 197l7 3,126,998 3/64 Palmer 197-82 ROBERT E. PULFREY, Primary Examiner.

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