US3028942A - Escapement mechanism - Google Patents

Description

April 10, 1962 P. F. PAGE 3,02

ESCAP EMENT MECHANISM Filed March 28, 1961 INVENTOR PAUL E PA ATTORNEYS 3,028,942 ESCAPEMENT MECHANISM Paul F. Page, Newington, Conn, assignor to Royal Mc- Bee Corporation, Port Chester, N.Y., a corporation of New York Filed Mar. 23, 1961, Ser. No. 98,847 3 Claims. (Cl. 197-88) This invention relates to an escapement mechanism for business machines and the like; and more particularly relates to a novel escapement mechanism for typewriters whereby an automatic repeat letter spacing movement of the typewriter carriage is made possible. During normal typing operations it is often desired to move the carriage through several letter spacing movements before resuming typing. This is usually accomplished by repeatedly depressing the space bar of the machine. If a relatively large number of depressions are frequently required it will be apparent that such operations may become time The instant invention conand control therefor which upon operation normally permits the single space movement of the typewriter carriage, but which may be conditioned so as to permit an automatic repetitive operation of the escapement mechanism whereby said carriage may partake of a continuous stepping movement in a letter feed direction.

()ne object of the instant invention is to provide a very simple reliable arrangement for automatically repeatedly operating the escapement mechanism of a typewriter or the like.

Another object of the invention is to provide a novel self-tripping escapement mechanism which is capable of repeatedly releasing the carriage for a stepping movement in a letter feed direction in response to a previous incremental stepping movement of said carriage.

Another object of the invention is to provide a control arrangement for a typewriter escapement mechanism which may be conditioned so that the movement of the teeth of the escapement wheel serves to actuate the escapement control dogs in a manner which permits a continued automatic operation of the escapement mechanisrn.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings in which like reference numerals designate like parts throughout the figures thereof and wherein:

FIGURE 1 is a bottom plan view of the principal parts of the instant apparatus.

FIGURE 2 is a top edge view of a portion of the apparatus as shown in FIGURE 1.

FIGURE 3 is a perspective view of the apparatus shown in FIGURE 2.

FIGURE 4 is an active view of the apparatus shown in FIGURE 2.

Referring to FIGURES 1-3 there is shown an escapement mechanism which comprises a wheel 11 formed with a plurality of circumferentially spaced teeth 12. Wheel 11 is secured to a shaft 13 which is suitably rotatably supported in the machine frame and which has mounted thereon a pinion gear 14 that meshes with a rack 15 that is fastened to the typewriter carriage 16 in the usual manner. The pinion 14 is connected in any well known manner so as to be rotatably fixed in only one rotative direction with respect to shaft 13. The carriage 16 is biased in a letter feed direction 17 by means of the usual carriage spring barrel 18. A dog supporting bail 29 is pivotally mounted on the machine frame 21 3,02 ,942 Patented Apr. 10, 1 962 ice ' and is provided with a relatively fixed dog 23. A movable dog 24 is pivotally mounted on the bail 20 by means of a pin 25 and is capable of moving through a small are into and out of even registry with the operative abutment surface of the adjacent dog tooth 31. The dog 24 is biased to the non-registering clockwise position shown in FIGURE 1 by means of a lever 26 that is pivotally mounted on bail 20 by means of a stud 27 and is biased in a clockwise direction by means of a spring 30. Teeth 31 and 32 are formed on dogs 23 and 24 respectively and when unrestrained the tooth 32 is slightly offset from tooth 31 as shown in FIGURE 1. A spring 33 is secured to a projecting arm 34, FIGURE 4, of the bail 20 so that said bail is normally biased to a position wherein the movable dog tooth 32 is in its said registering position with respect to dog tooth 31 and is in operative engagement with a tooth 12 of the escapement wheel 11' thereby restraining the typewriter carriage 16 from incremental movement in the letter feed direction 17. The dog supporting bail Ztlis adapted to be oscillatorily swung through a relatively small are about the pivot axis of studs 22 so that the dog teeth 31 and 32 alternately move into and out of the operative path of movement of the teeth 12 of the escapement wheel 11.

In that the construction and operation of the above described escapement apparatus 'is'similar to that presently being used in the portable typewriter produced by the Royal McBee Corporation, further detailed discussion thereof need not be made here. This conventional type escapement device is here supplemented as follows.

' A pawl supporting arm, 35, FIGURE 3, is pivotally mounted on the machine frame 21 by means of a pivot pin 36 and is biased in a counter clockwise direction into normal engagement with an ear 37 of a control or key lever 38 by means of a spring 40. Pivotally mounted on one end of the pawl supporting arm 35 is a pawl 41 which is formed at its right end, as seen in FIGURE 3, with a tooth 42 and at its other end with a bent oif tail 43. A projecting stop arm 44 is secured to the frame 21 and extends beneath the tail portion of the pawl 41. When the pawl supporting arm 35 is in its said normal position the pawl 41 is held in an inoperative position, i.e. the pawl tooth 42 lies out of the path of movement of the escapement wheel teeth 12 and the limits of any ineffective random pivotal motion of the pawl 41 will be determined by the side face of the dog 23 and the stop arm 44. Under these conditions the escapement mechanism may be cyclically operated in the usual step by step manner in order to obtain the desired single space movement of the typewriter carriage in response to the individual depressions of the space bar.

When an automatic repeat operation of the escapement mechanism is desired the control lever 38 is displaced so that the lever ear 37 swings the pawl supporting arm 35 in a clockwise direction, as viewed in FIGURE 3, towards an operative position. This action will bodily move the pawl 41 upwardly so that the pawl tooth 42 engages the side face of the then adjacent tooth 12 of the escapement wheel. Continued bodily upward movement of the pawl will thus cause the pawl tall 43 to engage and upwardly displace the dog 23 of the escapement mechanism against the action of spring 33 as seen in FIGURE 4. This will serve to initiate an escapement cycle and as soon as the escapement wheel 11 starts to rotate in a counter clockwise direction, as viewed in FIG- URE 3, the said adjacent wheel tooth 12 will swing away and the pawl tooth 42 will be freed for upward movement, as seen in FIGURES 3 and 4, under the action of the spring 33 which now can swing the bail 20 and the dogs 23 and 2.4 in a clockwise direction back to a normal position thus permitting the escapement wheel to partake of the final portion of its incremental arcuate travel. The execution of this final portion of the incremental wheel movement however will bring the next tooth 12 into camming engagement with the pawl tooth 42 so that the pawl is caused to again rotate in a clockwise direction, FIGURE 4, thus automatically initiating another cyclic escapement producing movement of dogs 23 and 24 which after completion may be followed by a similar initiation of yet another cyclic operation of the said dogs. As will be apparent as long asthe control lever 38 is held in its displaced condition the pawl 41 will be positioned so as to cause a self-tripping or automatic repeat action in the operation of the escapement mechanism thus permitting the typewriter carriage to partake of a continuous stepping movement in the letter feed direction 17. When the pawl 41 is restored to its normal inoperative position the escapement mechanism may thereafter be operated in the usual step by step manner. As will be apparent this relatively simple and inexpensive arrangement for the pawl 41 and its supporting arm 35 constitutes an expeditious means for obtaining an automatic repeat action for the letter spacing movements of any spring biased typewriter carriage whether or not the typewriter happens to be a manual or an electric machine.

While there is in this application specifically described one form which the invention may assume in practice, it will be understood that this form of the same is shown for purposes of illustration only and that the invention may be modified and embodied in various other forms without departing from its spirit or the scope of the appended claims.

The invention claimed is:

1. In a typewriter, a frame, a carriage movably mounted on said frame, means for biasing said carriage for movement in a letter feed direction, an escapement mechanism for controlling the incremental stepping movements of said carriage in said letter feed direction; said escapement mechanism comprising a toothed member operatively connected to said carriage, dog means cooperating with said tooth member and movable so as to permit a single step movement of said carriage in said letter feed direction, camming means conditionable so as to be operated by said toothed member and operative thereby, to

move said dog means through an operative displacement,

and means for shifting said camming means from an operative position to an inoperative position.

2. In a typewriter having a frame, a carriage movably mounted on said frame, spring means for yieldably biasing said carriage in a letter feed direction, and an escapement mechanism for controlling the incremental movement of said carriage in said letter feed direction; said escapement mechanism comprising a toothed escapement wheel operatively geared to said carriage, dog means oscillatably mounted on said frame and adapted to cooperate with the teeth of said escapement wheel so as to permit said carriage to move in single steps in said letter feed direction, and a pawl movably mounted on said frame and having a camming portion adapted to cooperate with the teeth of said escapement wheel and another portion adapted to engage and operate said dog means, said pawl being constructed and arranged for movement between operative and inoperative positions and when in said operative position and when said dog means are actuated so that said escapement wheel is permitted to thereby rotate through an incremental distance the resultant camming displacement of the pawl by a Wheel tooth serves to again operate said dog means so as to permit another operative incremental displacement of said escapement wheel whereby said escapement mechanism is automatically repeatedly operated to permit said carriage to partake of a continuous stepping movement in said letter feed direction.

3. In combination with an escapement mechanism for controlling the movement of a spring biased typewriter carriage having a toothed Wheel operatively geared to said carriage, and a pair of dogs oscillatably mounted so as to sequentially cooperate with the teeth of said escapement wheel so as to permit a normal single step movement of said carriage; a movable pawl support member, and a pawl pivotally mounted on said member, said member being constructed and arranged on the machine frame so as to bodily move said pawl between inoperative and operative positions, said pawl having a tooth at one end thereof which when said pawl is moved to said operative position is adapted to cammingly cooperate with the teeth of said escapement wheel, said pawl also being formed with a tail which is adapted to actaute said dogs in response to the pivotal movement of the operatively positioned pawl caused by the camming action between the said pawl tooth and the teeth of said escapement wheel, the pivotal movement of said pawl being timed with respect to the movement of the other parts of the escapement such that said pawl initiates a new oscillatory cycle of movement of said dogs in response to the completion of an increment of movement of said escapement wheel whereby an automatic repeat actuation of the escapement mechanism continues to occur during the time that said pawl support member holds said pawl in its said operative position.

References Cited in the file of this patent UNITED STATES PATENTS 937,336 Stickney Oct. 19, 1909

Images