US2439456A - Power operated case shift mechanism for typewriting machines - Google Patents

Description

Patented Apr. 13, 1948 T OFFICE CASE SHIFT MECHA- NISM FOR TYPEWRITING MACHINES POWER OPERATED Ronald D. Dodge,

to International tion, York Poughkeepsie, N.

Business Machines Corpora- New York, N. Y., a corporation of New Y.,` assignor Application November 10, 1944, Serial No. 562,'789

9 Claims. (o. 197- 74)` This invention relates to typewriting machines.

'I'he principal object of the present invention is to provide an improved power Operating mechanism for typewriting machines.

An object is to provide a power Operating mech anism which is smoother and more positive in its action upon the devices operated thereby.

An object is to provide a power Operating mechanism which actuates positively in both directions instead of positively in one direction with im- 1positive restorationby a spring in the other direcion.

An object is to provide a power Operating device for typewriting machines which is especially suitable for Operating the shift mechanism.

An object is to provide a power operated shift mechanism which is Simpler, more positive, and quieter in its operation than power shift mechanisms heretofore used.

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. 1 is a vertical section through a power mechanism embodying the present invention showing the parts of the power mechanism in the normal position.

Fig. 2 is a vertical section showing certain of the parts in partly operated position.

The invention is shown in the drawings as applied to the well-known E1ectromatic" typewriter. It will be understood, however, that the invention is not limited in its application to the specific form of typewriter selected for purposes of illustration but may be applied to other typewriters equally as well.

In the well-known "Electromatic" typewriter the power mechanism comprises a main power roller which is designated I in the drawings with which cooperates a series of cam units, each controlled by a key and connected to operated devices such as type bars, the Shift mechanism, the carriage return mechanism, and so on. The present invention contemplates making use of this main power roller ID in conjunction with a second power roller and a modified form of cam unit to obtain a smoother and more positive operation of devices in such machines, particularly the Shift mechanism which ordinarily is fairly noisy on ao count of the mass of mechanism which must be moved by the shift cam unit to eiiect the shiiting of the type bars from one case position to the other.

i 2 In Fig. 1 the'numeral ll designates a portion of the type basket which is mounted on leaf springs` |2 in a well-known way and which includes an adjustable stop |3 comprisin g a headed screw threaded into a lug Ha forming part of the type basket. The head of the screw I 3 limits movement of the basket to its upper position, in which the lower case characters will be printed, by tcooperation with a stop post or strip 14 secured to the main frame work, the post being provided with a hole through which the shank of the screw !3 passes. There are four of the springs I2 arranged in two pairs at the sides of the machine to form "parallel motion links which cause the type basket to move in substantially a straight line through the relatively short distance necessary to aifect a changein case. The stop screw !3 carries a threaded collar |5 which limits the downward movement of the type basket to the upper case position by engaging the upper side of the -post 14. It will be understood that there are two of the stop screws |3 and two of the posts i [4 located at the sides of the machines to hold` the type basket level in either of its case shifted positions. i i i Adjustably mountedon the sides of the type basket I I are the arms Hi of which there is one on to a cross shaft !8 suitably journaled in the frame i work. By rocking the shaft |8 counterclockwise, the type basket l i willbe drawn downwardly to the upper case position. -For the purpose of effecting this movement of the type basket, there is provided a power operated mechanism which is controlledby a Shift key |9 pivoted on the fulcrum wire` 20 extending across the machine and acting as a pivot for all of the keys of the keyboard. i

This power Operating mechanism includes the main power roller o which cooperates with the usual cam units Operating the type bars (not shown) in thevbasket I and a second power roller 2|` mounted on theishaft 22. This second power roller ZI 'is driven by the main power roller Zt through a 'belt 23 which passes around pulley groovesformed in the ends of the power rollers I!) and 2 l. i t

Pivoted on a cross rod 24 which pivot's the front cam units (not shown) which operate the type bars and other devices is a cam unit 25 comprising an assembly including a frame having the general form ofa right angle lever, one of the arms of which is connected by a link 26 to a rock lever 21 pivotecl at 28 on the main frame work of 'the machine. An arm of lever 21 is connected by 'pivoted at 259 is a a pin and slot connection 29 to one of the arms l'l whereby rocking of lever 21 in a counterclockwise direction will result in drawing down the type basket to the upper case position.

The cam unit 25 includes a frame 25a in which a substantially circular cam 256 is eccentrically pivotally mounted at 250 and the cam 25b is provided with a circular cutaway portion 25d which normally confronts the power roller 2! to provide a clearance which normally prevents the cam 25b' from being rotated by the power roller 2 l When the type basket is in the lower case position the periphery of the cam 2517 is clear ofthe main power roller n. r

The cam 25b is provided with two projections 256 which may take the form of bosses and are located equal distances on diametrically opposite sides of the 2517. In the normal position of the cam 251), as shown in Fig. 1, a spring actuated arm 253* engages theside of the lower boss 256 and tends to urge the cam 2517 in a clockwise direction. The arm 257' is pivoted at 25g to frame 25a 'of the cam unit and is urged .in a 'clockwise direction by torsion spring 2517.. .The cam 251) is also provided with two stop lugs 252', 257'. Also detent lever 2579 having a bent over lug 251 normally engaging the lug 252' thus preventing the cam 25b from rotating clockwise. The key!!! is provided with an extension l9a having a-slot embracing a pin 25172 carried by the arm of the detent lever 257c opposite the one. carrying thelug engaging 251.

The operation of these parts will now be explained in detail.

It will be assumed that the operator desires to Shift type basket II to enable upper case type characters on the type ,bars to print on the work sheet. To effect this result the operator depresses the Shift 'key l9. This causes the detent lever Zk to rock in counterclockwise direction thereby releasing the lug 251 on the detent lever 2515 from the lug 251. This permits'the spring arm 25f to rotate the cam 25b a limited amount in a clockwise direction thereby causing the circular portion, of the cam 251 to engage the periphery ofpower roller zl. The cam 25b is now driven positively by the power roller 2| through half a revolution to the position of Fig. 2. Thus the cam 2519 in effect rolls over the periphery of the roller 21 and, on account of the eccentric mounting of the cam 25b on the cam unit frame; causes the frame of the cam unit 25 to be rocked clockwise therebythrusting upwardly on the link 26 and, through the lever 21, arms ll, and the links lsa, drawing down the type basket to the upper case position.

The case Shift key 19 will either be held down by the operator while Operating the desired character key or may be locked down by means of the usual shiit lock key (not shown) i The lugs 25i, 257' are so located on the cam 25b on opposite sides of the pivot 251) that when the detent lever 2570 is operated by the key as aforesaid and held in operated position, it moves out of engagement with the lug 25` into the path of the lug 257'. In other words, the lug 250' is located at a slightly greater distance from pivot 25c but almost'diametri'cally opposite the lug 25' Thus, When the cam 2519 is rotated a half revolution the lug 257" engages the lug ormed in the detent lever '.257c, as in Fig. 2, and

prevents further rotation of the cam 25b as long as the Shift key l9 is held depressed As a result of the depression of the key the type basket pivot 250 of the crcular cam V a toggle spring If now the operator releases the Shift key lt, i

the detent lever 257* will be rocked back to its originual position; shown in Fig. 1, and will therebyremovethe lug on the detent lever 2510 from engagement with the lug 259". This permits the cam 2517 to engage power roller lil and to make another half revolution, positively restoring the parts'to the position oi Fig. 1. Thiis the type basket is moved positively back to the position of Flg. 1 but the initial and terminal velocities of the type basket will below preventing the stop screw &3 from slamrning against the post l 4.

In order to yieldingly hold the lever 27 in either of its shifted positions there is provided 331 which engages pins carried by the end of lever zl m'oving the bar and slot connection 29 and by the main iframe; respectively. The spring se also causes the leverzl to move a little further irieach direction than the lever is actuated by the cam unit 25 for the purpose of carrying the cam unit to the position of Fig. 1, in which the cam 251 is clear of the power roller lil, or to the position of Fig. 2, in which the cam is clear of theipower roller ti. Without spring, the cam might drag on one or the other of the power rollers sa and 2! resulting in wear of the power' rollexi This spring is helpful in' preventing wear because the surface of the power roller is usually rubber which would have a groove worn in it if' the cam dragged One of the main advantages of the mechanism described above is that the type basket Shift mechanism can be simplified. Heretofore it has been customary to use the Shift mechanism disclosed in Patent No. l,945,097 in which the cam unit actuates a T-lever which is moved to alternate operative positions by a connection to the shift key. This Construction was made necessary by the fact that' the Shift cam unit usually hasa i double-lobed cam, and operates positively in only' one direction, being restored cycle of operation of the cam unit and then other direction by anthe necessity for using moved positively in the other half cycle without a T-lever which is shifted by the key between half cycles. Thus, relatively simple connections between the cam unit and the Shift mechanism may be used in the present case witha more positive action since the action is more direct and much Simpler. e

Another advantage oi the mechanism disclosed herein is that the touch required to actuate the shift key is greatly light-.ened and is no greater than the touch required for the character' keys because of the elimination of the T-lever which imposes a certain amount of additional load on theshift key.

A further advantage is by a spring. Onthe that the 'mecham'sm of an eccentric from and its approach to the dead i center position is effected with slow motion. It

follows that the type basket will be brought to a r stop smoothly before the power roller loses complete control of the cam 251).

A distinct advantage of the mechanism is that the operation of the type basket is more closely synchronized with the operation of the. shift key. When the shift key is in the position of Fig. 1, the type basket must necessarily be in lower case position since only in this positio is the stop lug 252', which determines the position 'of the cam in Fig. 1, in engagement with the lug on lever 2576. In other words, if the shift key were merely ipped with the finger and not held down, the cam 251) will always make `a complete revolution thus drawing the type basket down to its upper case position and then immediately thrusting it back to lower case position. In the shift mechanism disclosed in the above patent, if the key is flipped instead of being held down, the cam unit will draw the type basket down to upper case position but the T-lever will be restored immediately along with the key with the result that the second operation of the cam unit merely tends to repeat the efiect on the type basket and leaves the type basket in the upper case position.

While there have been shown and described and pointed out the fundamental novel features of the invention, as applied to a single 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 threfore to be limited only as indicated by the scope of the following claims.

What is claimed is:

1. In a power operated typewriter, a case Shiftablepart, a main power roller, a second power roller; a cam unit connected to said case Shiftable part and including a cam alternately operatively engageable with both said power rollers to effect both a positive shiit of said case shi'itable part and a positive restoring movement of said part, and including releasable means for causing the alternate engagement of said cam with said power rollers; and a shift key for controlling the releasable means.

2. A power Operating device for typewriters and the like comprising a pair of power drivers, a member adapted for actuating a device of the typewriter, cam means mounted on said member for engagement with one or the other of said drivers; means to cause the cam means to engage and be positively operated by first one and then by the other of said drivers, said cam means, when engaged with said power drivers, coupling the first member to the drivers for operation by the latter; and means for controlling the causing means.

3. In a power operated typewriter, a part to be actuated, a pair of power rollers; means connected to said part and mounted between said power rollers, including a rockable member and a coupling member carried thereby adapted to engage and be operated first by one` and then by the other of said 'power rollers, said coupling member when engaged with` one power roller being operated thereby` to rock said rockable member toactuate saidpart and at the same time carry the coupling member into a position to engage the second power roller for operation thereby, said coupling element, when engaged with the second power roller, rocking said rockable member to a position in which the coupling member may again belengaged with the first power roller and, simultaneously with said second rocking movement, actuating said part; means to cause said coupling member to engage said power rollers in the alternate positions of the rockable member, and a key for controlling the last named means.

4. A power mechanism'for typewriters comprising a. pair of power operators, a support member pivoted for rocking movement from each of said operators toward the other, an element carried by said support member and adapted to couple said support member to said operators for operation by one or the other of said operators according to the position to which the support member is rocked, means for operatively engaging the coupling element with one of the power operators in either of the rocked positions of said support member, and a key for controlling the enaging means.

5. In a power operated typewriter, a pair of rotary power operators; means adapte'd to be operated by said operators and mounted for movement between alternate positions from one of which positions said means may be moved by one of said operators to the other alternate position in which said means may be operatively coupled with the other operator, said means including a rotary element engageable with the respective operators in said positions to rendor said means operable by the respective power operators, and including means `for rotatably engaging said element with said operators; and means for rendering the engaging means efl'ective.

6. A power mechanism for typewriting machines comprising a pair of power rollers, a frame pivoted to swing between said power rollers; a substantially circular member eccentrically pivoted to said frame between said rollers and adapted to engage and be actuated by one of s id rollers, according to the position of said frame, when said member is initially rotated a small amount, said member, when rotated by either roller, causing said frame to move to a position to permit similar rotative engagement with the other roller for restoraton of said rqtation, means in both positions of said frame.

7. A power Operating mechanism for typewriters comprising a pair of power rollers, a cam frame mounted to Swing between said power' ing said cam to prevent said partial rotation in either of the positions of said frame, and means `for releasing said detent operable in either of the positions of said irame.

8. In com-bination with a shift mechanism having a part mounted for movement between two case shift positions, a pair of separate power actual-,ing members: means connected to said part and engageable with both of said members for operation by one or the other of said members according to the position of said part and y including a coupling element and means to engage the coupling element'with said members; and means for rendering the engaging means effective in either position of said part, including a key movable in one direction to cause the coupling element to engage one actuating member in one position of the case shiitable part and movable in another direction to cause the coupling element to engage the 'other actuating member in the other position of the case shiftable part.

9; In a, machine of the class described, a pair of separate power operators, a device alternately engageable with one or the other of said operators and, when engaged with either operator, being actuated thereby to a position to be ensaid device.

-eective with said device in one position and movable in another direction to renderthe causing means efiective in the alternate position of RONALD D. DODGE.

REFEEENCES CITED The following references are of record in the file of this 'patent:

UNITED STATES PATENTS Number Name Date 1,155,445 Sargent Oct. 5, 1915 1,688,380 Dorsey Oct. 23, 1928 1,945,097 Thompson et al. Jan. 30, 1934 e 2,188,935 Wittenmyer Feb. 6, 1940 2,275,759 Helmond Mar. 10, 1942 2,331,827 Dennis Oct. 12, 1943

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