US2153632A - Typewriter escapement mechanism - Google Patents

Description

April 11, 1939. KQ'CA 2,153,632

TYPEWRITER ESCAPEMENT MECHANI SM Filed May 18, 1957 40 0 I ae Patented Apr. 11, 1939 UNITED STATES PATENT OFFICE James F. Koca,

Woodstock, Ill.,

assignor to Woodstock Typewriter Company, Woodstock, 111., a corporation of Illinois Application May 18, 1937, Serial No. 143,334

3 Claims.

The present invention relates to a typewriter and more particularly to an escapement mechanism for controlling the spacing of the letters.

7 It is an object of the present invention to provide a new and improved escapement structure which will tend to eliminate the noise and vibration due to the impact of the elements during operation.

Yet another object of this invention is to provide an escapement structure for a typewriter in which the normal shock due to the sudden stopping of the carriage is greatly absorbed and which is operative even though more than one stop member is actuated to suddenly stop the carriage.

Numerous other objects and advantages will more fully appear during the course and progress of the following specification.

Fig. 1 is a rear elevation of an escapement constructed in accordance with the present invention.

Fig. 2 is a sectional elevation taken on the line 22 in Fig. 1.

Fig. 3 is a perspective view of a ratchet wheel pinion and associated pivot constructed in accordance with the present invention.

Fig. 4 is a perspective view of a pivot supporting sleeve made in accordance with the pres ent invention.

The particular typewriter, herein shown for the purpose of illustrating the present invention, is the popular, well known Woodstock typewriter although the invention is not confined to this particular type of machine.

The typewriting machine illustrated in part has a frame ill in which a carriage (not shown) is mounted to move in a transverse direction. The rack I2 is secured to the rear portion of the carriage and extends longitudinally thereof. 4 Suitable resilient means is, in the conventional manner, secured to the carriage and tends normally to draw the carriage and rack in the direction of the arrow (see Fig. 1). The stresses tending to displace the carriage are resisted by the engagement of the rack with a pinion I 4 which is rigidly held from movement in a clockwise direction, as viewed in Fig. l, by the pawl 16 pivoted to an escapement wheel 18 as at 20. The pawl I6 is normally maintained in engagement with the pinion It by means of the spring 22 secured to the escapement wheel. The pawl, however, is so arranged as to freely permit movement of the pinion i l in the counter-clockwise direction, as viewed in Fig. 1, so that the carriage may be readily returned in the usual manner against the action of the aforementioned resilient means.

The escapement wheel 18 has a plurality of teeth or projections 24 identical in number with the teeth upon the pinion l4 and is mounted upon a fixed pivot 26 for rotation thereabout. The central portion of the ratchet wheel extends transversely a considerable distance from the plane of the Web portion 28 to form the bearing sleeve 30. The pinion E4 in turn is mounted rotatably upon this cylindrical sleeve 30, as shown more in detail in Fig. 2, and the parts maintained in assembled relationship by the machine screw 32 threadedly engaging the pivot axially thereof.

The pivot 25 is provided with an axially extending, preferably cylindrical shank 34 for fixedly positioning the member, together with the ratchet wheel and the pinion, with respect to the frame of the machine. To this end the frame is provided with a bore 36 of substantially greater diameter than that of the cylindrical shank 34. Intermediate of the shank 34 and the bore 35, for supporting the latter firmly in operative relation, is an annular cylindrical sleeve 38 composed of some suitable resilient material such as rubber, cork or the like.

According to one preferred embodiment the sleeve 38 is tightly situated about the shank 34 and this assembly forced tightly into the bore 36. By suitably proportioning the various elements in the aperture the parts will be held firmly against all normal tendency of displacement. In order to additionally maintain the shank 34 in proper operative position, a pin 40 may be passed through the shank and sleeve, tightly joining the members together.

According to another preferred embodiment the pin 46 may be extended into the frame 10, thus serving to join the three elements positively in operative position. While a pin has been described, it will be obvious that set screws or various other means might be employed to maintain the parts in proper position without substantially interfering with the resilient mounting of the pivot 26.

The remainder of the escapement mechanism 42 is of a well known type, being supported generally on opposed pivots 44 and controlled by the space link 46 actuable from the space bar, keys or any other desired portion of the typewriter for the purpose of controlling the position of the stop dogs 48 and 50 with respect to the teeth of the escapement wheel 24.

It will be apparent that the transverse position of the carriage with respect to the platen is maintained by the forceful engagement of the dog 50 with the adjacent projection or tooth of the escapement Wheel. When the space link is actuated, as, for instance, when a key on the typewriting machine is pressed, the associated assembly is moved through a short are about the pivots 44, moving the dog 50 rearwardly of the machine until it slides-off the face of the adjacent projection on the escapement wheel 24. Immediately the aforementioned resilient means draws the carriage and the rack in the direction indicated by the arrows in Fig. 1. The pinion l4 engaging the rack I2 is accordingly rotated in the clockwise direction, as viewed in Fig. 1, as is also the escapement wheel 24 which is secured for uni-directional movement thereto by means of the pawl [6. Movement of the members ceases when the released projection upon the escapement wheel contacts the dog 48. As the space link 46 is released, the dog 50 moves back into the path of the next succeeding projection to position the plate accurately one space removed from its previous position.

The impingement of the ratchet wheel upon either or both of the dogs 48 and 50 under the influence of the inertia of the carriage, as well as the resilient means tending to draw it in the aforementioned direction, is normally a source of vibration and noise. During each spacing step the carriage, after being released by the dogs and given some momentum by the resilient means, is again stopped in such a manner that the momentum must be substantially instantaneously dissipated. This normally results in the creation of relatively high instantaneous impact forces.

The present invention provides a means whereby such shocks are largely absorbed and the operation of the typewriter rendered increasingly smooth, silent and efficient. At the'same time the elements of the escapement mechanism remain always in proper relative position. Thus, while supported with some degree of resiliency, the pivot 26 is nevertheless always maintained properly centered with respect to the aperture 36 in the frame 10 and accordingly cooperates with the remainder of the spacing control in the usual manner.

It is thought that the invention and numerous of its attendant advantages will be understood from the foregoing description and it is obvious that numerous changes may be made in the form, construction and arrangement of the several parts without departing from the spirit or scope of the invention, or sacrificing any of its attendant advantages, the form herein described being a preferred embodiment for the purpose of illustrating the invention.

I claim:

1. In a typewriter having a frame and a carriage, an escapement wheel, a stop member associated with the wheel for positioning the carriage, a pivot upon which the wheel is mounted for rotation with respect to the frame, said pivot being mounted on the frame, and a resilient sleeve surrounding a portion of the pivot and being interposed between the pivot and the frame whereby to provide a cushion.

2. In a typewriter having a frame, a carriage, a rack on the carriage and normally engaging a pinion, an escapement wheel associated with said pinion, a stop means engaging the wheel for positioning the carriage, a pivot pin supporting the wheel for rotation thereabout, said pin having an extension mounted fixedly in the frame, and a resilient sleeve surrounding the extension and supporting the pin in operative position in the frame whereby to resiliently center the pivot.

3. In a typewriter having a frame, a carriage and a spacing mechanism comprising an escapement wheel, escapement wheel mounting means pivotally supporting said escapement wheel for rotation with respect to the frame, said escapement wheel mounting means being mounted on the said frame, stop means adapted to engage the escapement wheel for positioning the carriage, said stop means being operatively supported on the said frame, and resilient means interposed between said escapement wheel mounting means and the typewriter frame to absorb impact and resiliently support the mechanism, said supporting means for said stop means being independent of said resilient means whereby to permit resilient absorption of impact vibrations by said resilient means relative to said coacting stop means.

JAMES F. KOCA.

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