US2858925A - Keyboard touch device - Google Patents

Description

Nov. 4, 1958- C. A. MULLER KEYBOARD TOUCH DEVICE Filed May 4, 1956 3 i we mm 5 m mm nm 3 Nv mm INVENTOR. CHARLES A. MULLER ATTORNEY anism for the resilient members.

Patented Nov. 4, 1958 KEYBOARD roucn DEVICE Charles A. Muller, WappingersFalls, N. Y., assignor to International Business Machines Corporation, New York, N. Y., a corporation of New York This invention relates to typewriters of the power driven class, and more particularly to an improved mounting device for resilient members which are engageable by key levers of a typewriter.

It has been found that an actuating key lever should be positioned for movement from an inoperative position through an actuating range, and then beyond that range and in the same direction through a non-functioning range to insure the initiation of a print stroke. However, it is wasted movement in the non-functioning range, and the operator should be encouraged to remove the finger from the key as soon as possible after the key lever leaves the functioning range. It should be noted that a key lever stroke should not be terminated abruptly by a mechanical stop exactly at the end of a function stroke as the feel of the keys would be harsh. Accordingly, the non-functioning movement should be provided wherein the operator has an opportunity to remove the finger without sensing a shock of impact. This makes it desirable that a signaling medium be provided for indicating the termination of a function stroke.

A signaling medium is shown and described in copending application Serial No. 437,104 filed June 16, 1954 and relates to resilient members, one for each of a plurality ,of typewriter key levers, wherein an unloaded auxiliary spring is positioned for engagement with one end of a key lever after it has finished its function stroke and While traveling through its non-functioning range. The resilient members are arranged for engagement by the key levers just after the key levers reach the end of a function stroke.

It has been found that the resilient members should be arranged for engagement by key levers at selected positions through the non-functioning range depending upon individual preference of the operator. Accordingly, it is an object of this invention to provide for adjustment of the resilient members to change their efiectiveness according to the touch desired by the operator.

It is a further object of the invention to provide an improved mechanism carrying the resilient members and being easily adjustable for positioning the members to suit the touch of the operator.

Other objects of the invention will be pointed out in the following description and claims and illustrated in the accompanying drawings, which disclose, by way of example, the principle of the invention and the best mode, which has been contemplated, of applying that principle.

In the drawings:

Fig. l is a side elevation of a type bar actuating mechanism having adjustable resilient members associated therewith.

Fig. 2 is a view taken on the plane of line 22 in Fig. l and showing details of the adjustable mounting mech- Briefly, resilient members attached to a mounting memposition in the non-functioning range to resist depression and to restore the key levers. The mounting member is movable to position the resilient members for operation during any stage of the non-functioning range by rotation of a wheel acting through a bar and bell crank attached to the mounting member.

Although forming no part of the invention, the type bar driving mechanism is described briefly to better illustrate the invention.

In Figure 1, a type bar 1 is pivoted about a shaft 2 for rotation from a rest position to strike a platen 3 for a printing stroke. A cam lever 4 is mounted for pivotal rotation about a shaft 5. The rotation of cam lever 4 about the shaft 5 in a clockwise direction causes a link 6 to drive the type bar 1 about the shaft 2 to printing position. The cam lever 4 is biased by a spring 7 in a direction to restore it to its rest position as-shown in Fig. 1. A cam 8 is mounted for pivotal movement about a stud 9 connected to cam lever 4. A spring 10 extends between a point 11 on the cam lever 4 and a point 12 on the cam '8 to bias the latter counter-clockwise about its pivot 9.

The cam 8 has a serrated tread 13 which is normally just out of engagement with the periphery of a power roll 14 that is rotated at a constant rate in a counterclockwise direction as viewed in Fig. l. The serrated tread 13 on cam 8 is eccentric with respect to pivot 9 and, when brought into engagement with the power roll 14, causes the cam 8 to swing clockwise about its pivot 9 to force the latter away from the power roll and swing the cam lever 4 about the, pivot 5. During a print stroke, the frictional drive between the power roll 14 and the serrated tread 13 ceases when the distance between the stud 9 and the power roll 14 is greater than the maximum radius of the cam 8 measured from the stud 9 to the serrations 13. After disengagement, the spring 10 returns the cam 8 to its rest position relative to the cam lever 4. The cam lever 4, link 6, and type bar 1 are carried by momentum for the remainder of the print stroke and are returned after the printing stroke by the spring 7.

To initiate the print stroke, a trip latch 15 is employed to rock the cam 8 until its serrations 13 engage the power roll 14. The latch 15 is supported for both pivotal and sliding motion with respect to a stud 16 carried by the cam lever 4. A spring 17 is connected between an ear 18 on the cam lever 4 and an car on the latch 15 for holding the latter normally in a position with its lefthand end engaging the ear 18 as shown in Fig. 1. A key lever 19 is arranged to pivot about a rod 20 and is held in the uppermost or rest position by a spring 21 connected between a hook 22 on the key lever 19 and a projection 23 on a guide comb 24. ,Depression of the key lever'19 causes a projection 25 on the key lever to rotate the trip latch 15 counter-clockwise until it engages the cam 8 and rocks the latter clockwise into engagement with the power roll 14. As previously described, the cam 8 is then actuated by the power roll to drive the type bar to printing position. The function stroke of the key lever 19 is complete when the latch 15 causes the cam 8 to engage the power roll 14, and further depression of the key lever has no effect, and therefore is described as passing through a non-functioning range.

In order to interrupt the travel through the non-functioning range, a resilient member 32 is held by a mounting member 33 in a position whereby a lower portion 34 ofthe key lever 19 will bear against the resilient member 32 when the key lever is depressed beyond the function stroke.

In accordance with the objects of the invention provision is made for adjusting the resilient member 32 so that it takes efiect at selected positions in the non-functioning range. To accomplish this result, the mounting member 33 carrying the resilient member 32 is provided with studs 36 which are slidably received in vertical slots 37 formed in stationary frame plate 38. A pair of bell cranks 40 are pivotably mounted on the frame 38 by a pair of studs 42, and projections 43 on the lower arms of the bell cranks extending through openings 44 in the frame to engage slots 45 in the mounting member 33. With this arrangement of parts, pivotal motion of the bell cranks 40 causes the mounting member 33 to move vertically. In order to effect pivotal motion of the bell cranks, a bar 46 is pivotally connected to the upper arms of the bell cranks as shown in Fig. 2. Fixed to the bar 46 at a point between its ends is a pin 48 which extends into a helical shaped slot or groove to in a circular disc or wheel 50 rotatably supported by a pin 51 on the frame plate 38. Rotation of the wheel causes the slot or groove 49 to act on the pin 4-8 and move the bar 46 longitudinally to effect a swinging of the bell cranks about their pivots. This causes the member 33 to be raised or lowered for positioning the resilient member 32 relative to the key lever 19.

In Fig. 2, the mounting member 33 is adjusted as far upwardly as possible so that the resilient member 32 engages the key lever at the beginning of its non-functioning stroke. operator receives a signal to interrupt the key stroke in the form of increased resistance at the key caps at the beginning of the non-functioning stroke. Accordingly, the key travel is short before increased resistance is sensed. Assuming that a longer key movement is desired before an increased resistance. is sensed, the operator rotates the wheel 50 counter-clockwise to shift the bar 46 to the right. This movement of the bar 46 causes the bell cranks 4b to pivot clockwise and lower the member 33 so that the key lever 19 engages the resilient member 32 later in the non-functioning range.

While there have been shown and described and pointed out the fundamental novel features of the invention as applied to a preferred embodiment, it will be understood that various omissions and substitutions and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art, without departing from the spirit of the invention. It is the intention, therefore, to be limited only as indicated by the scope of the following claims.

What is claimed is:

1. In a typewriter having a type bar, power driving means for driving same to a printing position, and a key lever for initiating a printing stroke movable through an actuating range and beyond it in a non-functioning range, a resilient device comprising, in combination, a resilient member engageable with said key lever in its direction of travel at a predetermined position in its non-functioning range and an adjustable device for varying the point of engagement comprising a frame plate, a slidable mounting member, means slidably connecting said mounting member to said frame plate for movement in a vertical direction, means mounting said resilient member on said slidable member, crank means coupled to said mounting ember effective to slide said member, manually operable cam means, and interconnecting means from said cam means to said crank means effective to rotate said crank means when said cam means is operated and thereby displace said resilient member with respect to said key lever for engagement within its travel in the non-functioning range.

2. In a typewriter having a type bar, a power driving means for driving the same to a printing position, and a key lever for initiating a printing stroke including means supporting said key lever for movement through an actuating range and beyond it in a non-functioning range, an adjustable device for resiliently resisting travel of said key lever through said non-functioning range comprising a resilient member engageable with said key lever, a slidable mounting member, a frame plate, means slidably With the device in this position, the

connecting said mounting member to said frame plate for movement in a vertical direction, means mounting said resilient member on said mounting member, crank means coupled to said mounting member effective to slide said member, a rotatable wheel including a cam portion therein, and interconnecting means from said cam portion to said crank means effective to rotate said crank means when said wheel is rotated and thereby displace said resilient member with respect to said key lever within its non-functioning range.

3. In a typewriter having a type bar, a power driving means for driving same to a printing position, and a key lever for initiating a printing stroke including means supporting said key lever for movement through an actuating range and beyond it in a non-functioning range, an adjustable device for resiliently resisting travel of said key lever at selected positons through said non-functioning range comprising a resilient member engageable with said key lever, a slidable mounting member, a frame plate, means slidably connecting said mounting member to said frame plate for movement in a vertical direction, means mounting said resilient member on said mounting member, crank means coupled to said mounting member effective to slide said member, a shiftable bar coupled to said crank means, an actuating pin coupled to said shiftable bar, and a rotatable cam disc coupled to said actuating pin for shifting said bar when said cam disc is rotated.

4. In a typewriter having a type bar, a power driving means for driving the same to a printing position, and a key lever for initiating a printing stroke including means supporting said key lever for movement through an actuating range and beyond it in a non-functioning range, an adjustable device for resiliently resisting travel of said key lever through said non-functioning range comprising a resilient member engageable with said key lever, a slidable mounting member, a frame plate, means slidably connecting said mounting member to said frame plate for movement in a vertical direction, means mounting said resilient member on said mounting member, a pair of pivot members cooperating to slide said mounting member, a shiftable bar coupled to said pivot members for operating same, and a rotatable wheel having a curved groove eccentric with respect to the center of said wheel, said groove coupled to said bar and adapted to cause said bar to shift when said wheel is rotated.

5. In a power driven typewriter having a key lever for initiating a printing operation, a cushioning device for said key lever comprising, in combination, a mounting member, a resilient element fixed to said mounting member and extending from the latter into the path of said key lever, a frame plate on said typewriter, means slidably connecting said mounting member to said frame plate for movement in a vertical direction so as to position said resilient element for engagement by said key lever at dilferent points in the movement of the latter, a pair of bell cranks pivotally connected to said frame plate and each having an arm engaging said mounting member for moving it in a vertical direction when said bell cranks are rocked about their pivots, a bar pivotally connected to another arm on each of said bell cranks, a disc rotatably mounted on said frame plate between said bell cranks and having a helical slot formed therein, and a pin fixed to said bar and projecting into said slot whereby rotation of said disc causes pivotal movement of said bell cranks.

6. In a typewriter having a type bar, power driving means for driving the same to a printing position, and a key lever for initiating a printing stroke movable through an actuating range and beyond it in a non-functioning range, a resilient device comprising, in combination, a resilient member engageable with said key lever in its direction of travel at a predetermined point in said nonfunctioning range and an adjustable device for varying said point of engagement comprising a frame, a member mounting said resilient member, means connecting said mounting member with said frame for movement in a vertical direction for varying said predetermined point, means including a crank coupled to said mounting member and rotatable to move said member, manually operable cam means, and means interconnecting said cam means and said crank for rotating said crank when said cam means is operated.

7. In a typewriter having a type bar, driving means for driving the same to a printing position, and a key lever for initiating a printing stroke including means supporting said key. lever for movement through an actuating range and beyond it in a non-functioning range, an adjustable device for resiliently resisting travel of said key lever in said non-functioning range comprising a resilient member engageable with said key lever, a mem- 15 10 said key lever.

References Cited in the file of this patent UNITED STATES PATENTS 1,462,913 Hess July 24, 1923

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