US2577467A - Back spacing mechanism operating means for typewriting or like machines - Google Patents

Description

F. KLOSKI I'AL BACK SPACING MECHANISM OPERATING MEANS Dec. 4, 1951 FOR TYPEWRITING 0R LIKE MACHINES Filed Sept; 13, 1949 Dec. 4, 1951 J. F. KLosKl ETAL 2,577,457

BACK SPACING MECHANISM OPERATING MEANS FOR TYPEWRITING OR LIKE MACHINES 2 SHEETS-SHEET 2 Filed Sept. 13, 1949 ---lxlll mw m51 Patented Dec. 4, 1951 UNITED STATES ATENT' OFFICE BACK SPACING MECHANISM OPERATING MEANS BIACHINES FOR TYPEWRITING OR LIKE Application September 13, 1949, Serial Nov. 115,542

9 Claims.

This invention relates to back spacing mechanism operating means for typewriting or like machines, and more particularly to means for operating back spacing mechanism by power supplied, e` g. by an electric motor.

An object of the invention is to provide a new and improved train of driving connections between a power generating machanism and the back spacing mechanism of a typewriter or like machine, the connections including cushioning means of novel construction adapted to minimize abruptness of operation of the back spacing mechanism, avoid jamming of the parts, and minimize noise and vibration.

Another object of the invention is to provide, for the operation of a back spacing mechanism, a train of connected elements including a toggle device adapted to cause the back spacing mechanism to start the carriage on its back spacing movement gradually, to then move it more rapidly, and to then decelerate it near the end of its .back spacing movement.

A further object of the invention is to provide means of the character referred to including a spring cushioned toggle device for transmitting drive to the back spacing mechanism.

Other objects of the invention Iwill become apparent from a reading of the following description of a preferred embodiment of the invention, the appended claims, and the accompanying drawings, in which:

Figure l is a View, partly in elevation and partly in vertical section, rfore and ait of `a typewriter embodying the invention, showing only some of the conventional or standard typewriter parts in order to illustrate the application of mechanism embodying the invention to a typewriter construction, the parts being shown in their normal or inactivepositions;

Figure 2 is a, fragmentary, substantially horizontal sectional view on the line 2 2 of Figure l, drawn Aon an enlarged scale;

Figure 3 is a fragmentary detail elevational view showing a cushion lever and toggle construction Iwith the parts in operated positions;

Figure 4 is a fragmentary View, partly in vertical 'seotion on kthe line '2 4 of Figure 1 and partly in elevation, showing parts of an escapement mechanism and a back spacing mechanism in their normal or inactive positions; and

Figure 5 is a fragmentary view, partly in vertical section and partly in elevation, showing vthe escapement and back spacing mechanisms illustrated in Figure 4, but with the parts in operated or 'active positions.

The invention may be embodied in typewriters or like machinesl of Various kinds, For the purposes of illustration, the invention is shown as being embodied in an oflice type typewriter haying, except for the power generating and transmitting mechanism to be described, many features in common with the well known vRoyal Standard typewriter. The drawings show only enough of the standard or known typewriter construction to assist in illustrating the manner in which mechanism embodying the invention may be coordinated with other parts of a typewriter construction.

The known construction illustrated includes a main frame A on which a carriage B equipped with a platen C is mounted for letter spacing and return movements by means of a top rail I secured to the carriage, and rolling upon balls 2, which in turn are adapted to roll on a framemounted bottom rail or track 3.

The carriage may be driven toward the left, that is, in the letter-spacing direction, by any suitable mechanism, for example, by a spring barrel 4 and draw band 5 of known or suitable construction.

For controlling the feeding of the carriage in letter-spacing direction to take place by letter space increments, the ,carriage is equipped with a rack 'E cooperable with an escapement mechanism generally designated D. The rack 6 is .carried by a bail I having arms 8-8 Apivoted on the carriage at 9--9 and Iurged by springs I-Il to rock counterclockwise as viewed in Figure 1 so as normally to hold the rack in engagement with an escapement pinion Il. The bail "l and rack 6 may be swung upwardly by any suitable means (not shown) so as to disengage the rack 6 from the pinion H to enable the carriage to be shifted manually in the usual manner. The pinion 1 I is coupled by a ratchet ,device (not shown) with an escapement wheel I2 journaled at I3 on an escapement frame orbracket I4.

The bracket 4 is equipped with cone-shaped bearing screws Iii-45 extending into conformingly shaped bearing recesses in mounting ears IS-l integral with an oscillatable escapement rocker plate Il. 'The plate I'I is equipped with the usual fixed dog I8 and limber dog I9 pivoted on the plate as at 20, and urged counterclockwise as viewed in'Figures 4 and 5 by a spring 2l interposed between a lheel 22 on the limber dog and an ear 23 on Athe rocker plate Il. An Vabutment screw 24 has threaded connection with a boss or lug 25 on the back `o-f the platev IL and can *be adjusted A4for determiningftheglimit of' rocking of the limber dog I9 when the latter is engaged by a tooth of the escapement wheel I2. An escapement wheel check pawl 26 pivoted at 21 on the rocker plate I1, is urged counterclockwise by a spring 28 interposed between ears 29 and 30 on the pa'wl 26 and plate I1 respectively.

When the rocker vplate I1 is oscillated back and forth, the dogs I8 and I9 will cooperate with the escapement wheel I2 in a well known manner for effecting the desired letter-spacing incremental movements of the carriage.

With the exception of power mechanism for operating it, the back spacing mechanism may be of known construction, and, as shown, is similar to the back spacing mechanism embodied in Royal Standard manually operated typewriters. As shown in Figure 4, a vertically movable thrust link 3|, adapted to be operated by power in a manner to be described later, is pivoted at its upper end, as at 32, to-a bell crank lever 33 mounted to rock about a pivot 34 on a fixed bracket 34a. Also mounted to rock about the pivot 34, and independently of the bell crank 3,3, is a rock arm 35, the upper end of which is pivoted to a thrust bar 36, as at 31. The bar 36 is bifurcated to provide upper and lower arms 36E and 36h. The upper arm 36a is provided with a pin 38 which is received in a slot 39 formed in a bracket 40 secured to the escapement bracket or frame I4, and is formed with an upwardly extending tooth 4I adapted to cooperate with the teeth on the rack 6 in a manner to be described later. The lower arm 36b of the bar 36 extends behind the bracket 46 as viewed in Figure 4, and the upper arm 36a extends in front of the bracket 40 so that the arms 36u and 361, being disposed on opposite sides of the bracket 40, guide the thrust bar 36 for reciprocation in the direction of carriage travel. For translating rocking of the bell crank 33 rst into rocking then into reciprocation of the thrust bar 36, the bell crank is formed with a heel 33a adapted to engage a projectiontIic on the thrust bar 36. A spring 42 interposed between a pin 43 on the bar 36 and an arm 44 on the bracket 40 normally maintains the thrust bar 36 and rock arm 35 in the positions shown in Figure 4.

An escapement wheel stop 45 is slotted to receive the pin 43 on the bar 36 and an adjustment locking screw 46, also carried by the bar 36, the arrangement being such that the stop 45 can be variably positioned longitudinally with respect to the bar 36, and then locked in adjusted position.

A rack lock lever 41 is mounted to rock on an adjustable pivot pin 48 carried by the bracket 40 and is formed with an arcuate upper end part 41a overlying the front bar of the bail 1 but normally being maintained free of engagement with the bail bar by a spring 49 interposed between an ear 50 on the rack lock 41 and an ear I on the bracket 40.

Normally the parts are in the positions shown in Figure 4. During typing, the escapement mechanism D is operated in the usual manner to enable the escapement wheel I2 and pinion II to rotate step by step in the direction of the arrow a to eect incremental letter-spacing movements of the carriage. In order to back space the carriage incrementally the thrust link 3I is moved upwardly in a manner described hereinafter-so as to rock the bell crank lever 33 and arm 35, and thereby move the thrust bar 36.toward the rightas viewed in Figure 4.

During the first part of the rightwara movement of the thrust bar 36, the pin 38 will move away from the inclined left end of the slot 39 in the bracket 40 so that the bar 36 will be free to be moved upwardly by the spring 42 and by the turning moment imposed on the bar 36 by the heel 332L of the bell crank lever 33. In this way the tooth 4I on the bar 36 will be moved into a tooth interspace on the escapement rack 6. Also during the rightward movement of the bar 36, the right-hand end of the thrust bar lower arm 36b will engage the rack lock 41 and swing it clockwise about its pivot so as to move its upper arcuate portion 41*3L into engagement with the top of the bail 1, thereby locking the bail against upward movement. At the same time the escapement wheel stop 45 will be moved into the position shown in Figure 5 so as to prevent reverse rotation of the escapement wheel I2. Continued movement of the thrust bar 36 toward the right, with its tooth 4I in engagement with the rack 6, will move the carriage one letter space toward the right, that is, in the return direction, as will be permitted by the ratchet coupling between the escapement wheel I2 and pinion I I. When the parts are returned from the positions shown in Figure 5 to the normal positions shown in Figure 4 by downward movement of the thrust link 3I, the ratchet coupling between the escapement wheel and pinion will hold the carriage in the back-spaced position to which it has been moved.

In general, the parts described so far do not, in themselves, constitute the present invention. The invention resides in other parts to be described, and combinations of such other parts with each other and with parts already described.

Broadly considered, vertical reciprocation of the thrust link 3I and consequent back spacing of the carriage are effected by power-driven means, generally designated E, which are made effective by depression of a manually operable back spacing key F. Power is transmitted from the powerdriven means E through a train of driving connections G. The construction and arrangement embodied in the train of connections G, to theA thrust link 3I so as to raise the latter and operate the associated back spacing mechanism in the manner previously described.

The power-driven mechanism E is generally similar to but embodies improvements in mechanism disclosed in the copending application of William H. Kupper, Serial No. 6,066, led February 3, 1948, now Patent No. 2,567,945, dated September 18, 1951. It includes a driving element, which operates continuously, and controllable driving connections, which normally are inoperative or ineffective, but which may be conditioned.

by the operator to effect operative driving connection between the continuously moving driving member and the train of connections G. The driver preferably is constituted by a continuously rotating element, more particularly a toothed snatch roll or bar 52, which may be of known form, and which is adapted to be driven in the. direction of the arrow b in Figure 1 by any suitable means, but preferably by an electric motor (not shown) The means for transmitting drive from the driver 52 to the connections G includes an actuator 53 which extends fore and aft of the typewriter and above the member 52. The actuator 53.

is' pivote'd as at 5d' to a lever 55 at a point off-set relatively' toi the pivotal-mounting 5e of the leverl on a fixed frame cross bar 57. The actuator has a forwardly extending part 58 projecting under an abutment or guide plate 55 mounted on the frame A, to extend parallel to the snatch roll' 52. A spring 65, interposed between'. the front end of the actuator 53 and an anchor plate 5l, yieldably urges the actuator to rock clockwise, and thus normally maintains' the actuator in the position shown in Figure l with` its front end part 58 bearing. against the abutment or guide plate 59. Another abutment 52 is disposed below the abutment 59', and is slotted to receive and guide the lowei` extremity of the actuator part 58 for sliding movements. The lever 55 normally is held in its inactive position, shown in' Figure' l, by a returning spring' 53 interposed'between an ear 65 on the lever and an anchorplate 55 mounted on the fixed cross bar 51 by screws, one of which is shown at 68. The lever 55 has a stop projection 5l engage*- ablev with a xed stop strip 68 for limiting the returning movement of the lever under the' urge of they spring 63.

In order to apply a power impulse to the train of driving connections G, the actuator 53 is operatively but indirectly connected to the driving member 52, the actuator itself never engaging the driving' member. Mechanism for bringing about this operative connection includes an interponent pawl element B5, pivoted as at 'l0 on the actuator. A spring ll, anchored to the actuator 53 and connected to the pawl 69', biases or urges the latter to rock clockwise so as to move its double toothed hose 59a into engagement with the snatch roll 52. Normally, the pawl is maintained out of engage'- ment with the snatch roll by the restraining action of a contr-ol element or tri-Eger l2 which is pivoted as at 'i3 on the actuator 53. in the normal position of the trigger, its rear Yend engages a. holding surface 'le on the pawl so as to prevent the'spring l-I from rocking the pawl 65 into drivetransmitting engagement with thedriving member 52. The pawl 55 is formediwith. an inclined resetter cam face l5 which is located just below the holding surface lil, and which is acted upon by the trigger for rocking the pawl counterclockwise, and thus resetting it in normal, inoperative position.

Operator controlled means for bringing about operative driving connection between the driver 52 and the actuator 53 includes the manually operable backy spacing key F pivoted as at l5 on the frame A. The key F has an upward projection 'IT disposed behind an arm 75 of an 'operating lever 19, pivoted as at 85 Von a frame-mounted cross bar 8l. The lever 15 has another arm t2 on which a limber dog or flipper Stils pivoted at 818. A spring 35 urges the limber dog 83 to rock clockwise to yieldably retain it in its norrna position of rest against a limit stop 85 on the lever arm 82. The dog t3 can swing counterclockwise from the position shown in Figure l, but cannot move clockwise from this position. A returning spring 8l, interposed between the key F and a short arm 88 on the leverr T5, yieldably holds the lever 'I5 and the key F in their normal positions. When the parts are in their normal positions the spring 8T holds the lever "i5 so that the lower end' of they limber dog il@ overlies a contact ear 58 on the actuator 53, and holds the key F so that a forward projection 95 on the key bears against a cushion stop: Si

In operation, when the back spacing key F is depressed, the lever 'le is rocked clockwise to causethe flipper 83 to push the actuator $3' downwardly to an initial extent suiiicient 'to bring the trigger 'l2 into engagement withthe abutment 62. This causes the trigger to'v be rocked clockwise about its pivot 13, sov asfto release the pawl 69, which is then moved by the spring 'II into engagement with the snatch roll 52. TheV snatch roll then drives the pawl 69 and actuator 53as a unit so as to rock the lever 55 and operate the back spacing mechanism through the train of connections G. When the pawl 59 is cast off from engagement with the snatch roll 52, the spring 60 lifts the actuator 53 to bring the trigger 12 into engagement with the upper, trigger-resetting abutment 59. This causes' the trigger 12 to be rocked counterclock Wise, so as to move itsV rearend against the resetting cam face 15 ofthe pawl 59, thereby re'- storing the latter to its inactive position. IThe parts of the mechanism E will then be returned to their normal positions by the spring 53.

Means are provided for adjusting or varying the amount of driving impulse generated .by the power mechanism E. This variation or adjust'- ment is eiected by variably limiting the extent to which the teeth on the actuator pawl nose 69a enter tooth intel-spaces on the snatch roll; 52 under the urge of the spring 'H when the ree straint of the trigger 12 on the pawl 59 is discontinued. In the form shown, the actuator 53 is provided with a downwardly extending stop element or ringer 92 which is disposed in front of and normally out of contact with a downiwardly extending stop part, heel, or linger 93 on the pawl 89. When ther pawl 69 is rocked clock'- wise by the spring Il so as to move the teeth on the pawl nose 69a into snatch roll tooth interspaces, the pawl stop 93 moves towardl the actuator stop 92, which may be so positioned as to be engaged by the stopl 93 to arrest rocking of the pawl 6'9- before the pawl teeth move tothe roots of the snatch roll tooth interspaces. By variably positioning one of the stops 92, 93, eg., by bending the stop Q2 towards or away from the stop 93, the extent tol which thel pawl teeth enter the tooth interspaces on the snatch roll can be varied. Consequently, the angle through which the snatch roll rotates while in contact with the pawl, which determines the amount of driving of the pawl and actuator 53 by the snatch roll 52, can be varied. Any suitable means or construction may be provided for adjusting one of the stops 92, 93 relatively to the other, but in the preferred construction the stop 92 is formed' in# tegrally with the actuator 53 so as to be bend-` able ktoward or awayl from the stop 93.

In typewriters or like machines in which all or some of the instrumentalities to be operated, e. g., type bars, carriage return mechanism, tabulating mechanism, escapement mechanism as well as back spacing mechanism, are operated by power, it may be desirable toprovide means for' varying collectively the extent of drivingof the several actuator pawls corresponding to the pawl 69 and associated with thecther mechanism referred to. This may be accomplished by providing a knock-ofi bar Se mounted on the main frame so as to extend under the front ends oi all of the actuators corresponding to the actuator 53 shown in Figure 1. Any suitable means (not shown), may be provided for adjustably tilting or otherwise variably positioning the knock-ori bar 94 so that it will be engaged by the lower ends of the actuators to control the timing yof disengage- 7 ment of tne associated actuator pawls from the snatch roll.

The train of connections G is so arranged, constructed, and coordinated with the power mechanism E and back spacing mechanism as to suppress or cushion the impact or concussion Which otherwise would be transmitted -abruptly from the power mechanism E to the back spacing mechanism. Accordingly, undesirable noise and harmful shocks are prevented, and danger of jamming of the machine with resultant damage is eliminated. In the construction shown, a pull link 95 is pivoted as at 98 to the lever 55 and is pivoted as at 91 to a cushioned toggle device generally designated 98. The link 95 preferably is constructed so as to be adjustable as to length, and to this end it comprises parts 95a and 95b which may be adjusted longitudinally with respect to eachother by an eccentric screw 95c extending through a slot 95d in the link part 95h, and being secured in adjusted position to the link part 95a. The link parts 95EL and 95lo may be locked in adjusted positions by screws 95e extending through slots 95 in the link part 95".

The toggle device generally designated 98 includes a toggle lever or link 99 mounted to rock about a fixed pivot |00, and a yoke or lever pivoted as at |02 on the link 99. The yoke |0| includes a part |03 formed with an ear |04 to which is secured one end of a spring |05, the other end 0f which is secured to an ear |06 on the link 99. The yoke |0| includes another part |01 to which the rear end of the link 95 is pivoted as at 91, as previously stated.

Another toggle link or lever |08 is pivoted at its lower end as at |09 to the link 99, and is pivoted at its upper end as at ||0 to the lower end of the thrust link 3|. Preferably, the pivot ||0 is of a well-known eccentric adjusting type.

Normally, the parts are in the positions shown in Figure l, wherein the toggle link pair constituted by the links 99 and |08 is broken and the thrust link 3| consequently is in its lower or normal position. When the key F is depressed so as to cause the actuator mechanism E to rock the lever 55 counterclockwise in the manner previously described, the link 95 will be pulled forwardly, or to the left as viewed in Figure 1. This will rock the interponent yoke part |0| momentarily about its pivot |02 on the toggle link 99 until the spring |05 is tensioned, Whereupon force will be transmitted through the spring to the toggle link 99 to rock the latter counterclockwise about the xed pivot |00. In this manner the toggle link pair constituted by the links 99 and |08 will be straightened or moved to the position shown in Figure 3, causing the thrust link 3| to be moved upwardly, thereby operating the back spacing mechanism shown in Figures 4 and 5 in the manner previously described. The sudden impulse caused by quick engagement of the actuator pawl 59 with the snatch roll 52 will be transmitted to the link 95 so as to accelerate the latter quickly, but since the actuating force is transmitted through the cushion spring |05 to the toggle pair 99-|08, the starting of upward movement of the thrust link 3| will momentarily be gradual so as to avoid harmful shocks in the operation of the back spacing mechanism. By the time the spring |05 has been fully tensioned by rocking of the interponent part |0| about the pivot |02, the thrust link 3| will be in its full upward movement. and the back spacing tooth 4| will have moved into engagement with the rack 6. Then, because of the still broken condition of the toggle device 08, the link 3| will be moved relatively rapidly so as to effect back spacing. As the toggle links 99 and |08 approach their straightened positions as shown in Figure 3, the thrust link 3| will be decelerated, thereby slowing down the back spacing movement of the carriage and bringing it gently to rest. Overthrow movement of the toggle device 98 is prevented by engagement of a stop projection on the link |08 with a stop ear l |2 on the link 99. The mutually engageable stops and ||2 limit the operation of the back spacing mechanism, but any continued driving movement of the link following engagement cf the stops will be dissipated in or absorbed by expansion of the toggle cushion spring |05. At or near the conclusion of the back spacing movement, the pawl lS9 will become disengaged from the snatch roll 52 in the manner previously described and the spring 63 will return the mechanism E and connection train G to their starting positions.

If the key F should be depressed and the actuator 53 and pull link 95 operated when the carriage is blocked at the limit of its return travel by the usual margin stop equipment, with resultant blocking of the thrust bar 35 and associated parts of the back spacing mechanism, the spring |05 will yield to enable the link 95 to reciprocate idly Without jamming or damaging the parts.

The mechanism disclosed embodies the invention in a preferred form, but it is intended that the disclosure be illustrative rather than de-v nnitive, the invention being defined in the claims.

We claim:

1. In power operating mechanism for a typewriter or like machine, a carriage back spacing mechanism; a driving member; an actuator; means including a cushioned motion-transmitting connection interposed between said actuator and said back spacing mechanism; an interponent mounted on said actuator for movements into and out of operative engagement with said driving member and being biased to move into engagement therewith; a trigger normally maintaining said interponent disengaged from said driving member; a manually operable back spacing control element; means responsive to depression of said element for actuating said trigger to release said interponent and enable it to move into engagement with said driving member, whereby said actuator will be driven by said driving member so as to operate said back spacing mechanism; and trigger re-setting means effective upon return movement of said element when said driving member is stationary for moving said trigger reversely to its releasing movement and thereby disengaging said interponent from said driving member.

2. In a power operating mechanism for a typewriter or like machine; a carriage back spacing mechanism; a rotatable driving member; a movably mounted actuator; means including a cushioned motion-transmitting connection interposed between said actuator and said back spacing mechanism; an interponent mounted movably on said actuator; a spring urging said interponent to move into drive-transmitting engagement with said driving member; a trigger mounted movably on said actuator and normally occupying a position in which it maintains said interponent out of drive-transmitting engage.

`ment with said driving member; an abutment;

and manually controlled means for imparting to said actuator suiiicient initial movement to move l said trigger into engagement with said abutment to thereby move said trigger on said actuator' and release said interponent to enable the latter to be moved by said spring into drive-transmitting engagement with said driving member, whereby said actuator will be driven by said driving member so as to operate said back spacing mechanism.

3. In a power operated typewriter or like machine, a carriage back spacing mechanism; a driving member; a train of connections between said driving member and said back spacing mechanism including an actuator drivable by said driving member, a rst pivoted lever, means connecting said lever to said back spacing mechanism, a second lever, means pivotally mounting said second lever on said rst lever at a point spaced from the pivotal axis of said first lever, a force transmitting and cushioning spring interposed between and connecting said levers, and means operatively connecting said second lever to said actuator and being operable by said actuator to rock said second lever whereby to transmit force through said spring to said rst lever to rock the latter and operate said back spacing mechanism; and manually operable means for controlling transmission of drive from said driving member to said actuator.

4. In a power operated typewriter or like machine, a carriage back spacing mechanism; a continuously driven rotary toothed snatch roll; a train of connections between said snatch roll and said back spacing mechanism including an actuator normally disconnected from said snatch roll but being controllably connectable therewith substantially instantaneously, whereupon the actuator is abruptly accelerated from rest position, a iirst pivoted lever, means connecting said lever to said back spacing mechanism, a second lever, means pivotally mounting said second lever on said rst lever at a point spaced from the pivotal axis of said rst lever, a force transmitting and cushioning spring interposed between and connecting said levers, and means operatively connecting said second lever to said actuator and being operable by said actuator to rock said second lever whereby to transmit force through said spring to said rst lever to rock the latter and operate said back spacing mechanism; and manually operable means for controlling connecting of said actuator to said snatch roll.

5. In a power actuated typewriter or like ma- 4 chine, a carriage back spacing mechanism; a driving member; a train of connections between said driving member and said back spacing mechanism including an element operable by said driving member, and a toggle device constituted by two toggle links pivoted together and respectively connected to said element and said back spacing mechanism; mutually engageable stop parts on said links for limiting straightening of the toggle device; and manually operable means for controlling transmission of operating effort from said driving member to said element.

6. In a power operated typewriter or like machine, a carriage back spacing mechanism; a driving member; a train of connections between said driving member and said back spacing mechanism including an element operable by said l0 driving member, a toggle device constituted by two toggle links pivoted together, means connect ing one of said links to said back spacing mechanism, mutually engageable stop parts on said links for limiting straightening of the toggle device, and a cushioning force transmitting spring interposed between said element and the other of said links; and manually operable means for controlling transmission of operating effort from said driving member to said element.

7. In a power operated typewriter or like machine, a carriage back spacing mechanism; a driving member; a train of connections between said driving member and said back spacing mechanism including an element operable by said driving member, a iirst toggle link mounted to rock about a fixed pivot, a second toggle link pivotally connected to said first toggle link and to said back spacing mechanism, an interponent pivotally mounted on said rst toggle link, means connecting said interponent to said element to be operable thereby, and a cushioning force transmitting spring interposed between said interponent and said irst toggle link; and manually operable means for controlling transmission of operating eiort from said driving member to said element.

8. In a power operated typewriter or like machine, a carriage back spacing mechanism; a driving member; and a train of connections between said driving member and said back spacing mechanism including an element operable by said driving member, a first toggle link mounted to rock about a fixed pivot, a second toggle link pivotally connected to said first toggle link and to said back spacing mechanism, an interponent pivotally mounted on said iirst toggle link, means connecting said interponent to said element to be operable thereby, a cushioning force transmitting spring interposed between said interponent and said first toggle link for rocking the latter to straighten the toggle formed by said two links and thereby operate said back spacing mechanism, and mutually engageable stop parts on said links for limiting straightening of the toggle.

9. In a typewriter or like machine, a carriage back spacing mechanism; an operating member; and a train of connections between said operating member and said back spacing mechanism including a rst toggle link mounted to rock about a xed pivot, a second toggle link pivotally connected to said first toggle link and to said back spacing mechanism, an interponent pivotally mounted on said rst toggle link, means connecting said interponent to said operating member to be operable thereby, and a cushioning force transmitting spring interposed between said interponent and said rst toggle link.

JOHN F. KLOSKI. WILLIAM H. KUPPER.

REFERENCES CITED The following references are of record in the iile of this patent:

UNITED STATES PATENTS Number Name Date 1,614,475 Hokanson Jan. 18, 1927 1,667,007 Hokanson Apr. 24, 1928 1,781,571 Degener Nov. 11, 1930 1,984,410 Hart Dec. 18, 1934

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