US800801A - Type-writer escapement. - Google Patents

Description

N0. 800,801. PATENTED OCT. 3, 1905. E. J. FAIRFIELD.

TYPE WRITER ESGAPEMENT.

APPLICATION FILED MARJO, 1902.

UNITED STATES PATENT OFFICE.

EDMUND J. FAIRFIELD, OF HARTFORD, CONNECTICUT, ASSIGNOR OF ONE- THIR-D TO AUSTIN C. DUNHAM AND ONE-SIXTH TO PHILANDER C. ROYCE, OF HARTFORD, CONNECTICUT, AND ONE-SIXTH TO M. BRAD- FORD SCOTT, OF WEST HARTFORD, CONNECTICUT.

TYPE-WRITER ESOAPEIVI ENT.

Specification of Letters Patent.

Patented Oct. 3, 1905.

Application filed March 10, 1902. Serial No. 97,424.

To all whmn it may concern.-

Beitknown that I, EDMUND J. FAIRFIELD, a citizen of the United States, and a resident of Hartford, in the county of Hartford and State of Connecticut, have invented certain new and useful Improvements in Type-Writer Escapements, of which the following is a full, clear, and exact description, whereby any one skilled in the art can make and use the same.

This invention relates to the class of escapements which are embodied in a type-writing machine in which there is a power-driven carriage, the movements of which are controlled by keys through the medium of an escapement 5 which is operated by the movement of the keys or the universal bar of the machine.

The object of the invention is to provide for a type-writing machine an escapement that can be used at a fast or slow rate of speed and yet have the carriage completely under the control of the operator; and a further consideration is the simplicity and cheapness of the structure for the purpose intended.

Referring to the accompanying drawings, 2 5 forming part hereof, Figure 1 is a top View of the escapement,with parts of the type-writing machine to which it is applied broken away. Fig. 2 is a view in elevation, showing the escapement in normal position for use. Fig. 3 3 is a view in elevation of the escapement illustrating the position of the parts when the normally disengaged dog is thrown into engagement with the escape-wheel.

The escapement forming the subject-matter of my invention is adapted to be used in a type-writing machine of ordinary construction in which there is a toothed bar, sometimes called the rack-bar, usually borne on a power-impelled carriage, and as the general 4 construction of such machines is well known in the art only so much of the parts is illustrated herein as to enable the relation of the escapement device to the mechanism of the type-writing machine to be understood.

In the accompanying drawings the letter a denotes the rack-bar of a power-impelled carriage of a type-writing machine, to the frame of which the escapement b is attached in any convenient manner.

In the preferred form shown there is a bracket 0, arranged to be removably secured to a part (Z of the frame of a type-writing machine, and on this bracket or base-piece is mounted a rotary shaft 0 in a suitable bearing f. On this shaft 6 is a pinion g, the teeth of which are in mesh with the teeth of the rack a in such manner that the rotary movement of the shaft will permit a movement of the rack-bar and the platen-carriage which supports it. On the outer end of this shaft 0 is an escape-wheel it, the teeth of which have bearing-surfaces in lines parallel to the axis of the shaft. These teeth h are preferably in the form of pins, as illustrated in the drawings. On the bracket 0 two loose pawlst'and 1 6 are pivotally mounted, so as to swing in planes which cross the line of the axis of the shaft. The pawl t has a detent-tooth 2', ar-

ranged to lie in the path of rotary movement 1 of a tooth h and to hold the escape-wheel in a position of rest when the pawl is in its normal holding position. The other pawl has a deten t-tooth is, which in the rocking movement of the pawl is swung forward across the path of movement of one of the teeth it just previous to the moment when another tooth is about to be released by the swinging movement of the pawl t'. The pawl 76 has an arm on which a collar Z, Fig. 2, is pivoted, and through this collar a connecting-rod on extends from the universal bar or that movable part of the mechanism of the type-writing machine which is actuated by the movement of the key-levers in printing. The collar Z is connected to the rod in any convenient way, as by being held between adjustable collars Z and Z which are arranged to be clamped to the rod m, as by means of screws, as shown in Fig. 1 of the drawings.

A pawl-spring n is supported on the machine or attached part with one end arranged so as to hold the pawl t' with a yielding pressure in its position to engage a tooth of the escape-wheel and prevent rotary movement of the latter. On the other pawl it a trip 0 is mounted, and this is preferably in form of a screw which extends through a threaded socket in a stud 0 fast to the pawl is. When the pawl 7c is moved, as by depressing the keylever, the end of the trip strikes against the pawl 2' and forces the detent-tooth t out of engagement with the tooth h of the escapewheel. By this same movement the detenttooth 7c is swung into position in the path of rotary movement of the teeth of the escapewheel, so that when one of these teeth is re leased from the hold of the pawl 11 the detenttooth on the pawl X: will be in position to arrest the rotary movement of the wheel and hold the carriage in the proper position to receive the impact of the type in printing. This imprint of the type takes place between the release of one tooth 71. of the escape-wheel from the detent-tooth v," and the engagement of this detent-tooth 2 with the next succeeding tooth ot' the escape-wheel, the carriage being held in this intermediate posit-ion by the engagement of the detent-tooth Z." with a tooth 72/ in substantially the position as illustrated in Fig. 3 of the drawings. The keylever is depressed in the act of printing, and when the downward pressure upon the key is removed the releasing movement reverses the direction of tilting movement of the detent lever or pawl and disengages the detentto0th 70 from a tooth of the escape-wheel, so that the parts pass from the position shown in Fig. 3 to that shown in Fig. 2, except that the escape-wheel has rotated one tooth-space and the tooth 71 engages the tooth 72 on the escape-wheel next in rear of the tooth it with which it was engaged at the beginning of the movement described.

Of the two loose pawls used in the embodiment of my invention one, as 2 is normally engaged with a tooth of the escape-wheel and the other, as Z1, is normally disengaged.

A trip device or equivalent construction that enables the movement of the normally disengaged pawl to move the other pawl out of engagement with a tooth of the escapewheel forms a feature of my invention. This trip device is shown as a separate element; but that is not essential.

It is not necessary that the two pawls should be made of the precise shape or should be arranged precisely as shown in the accompanying drawings, as various modifications as to the manner of engagement of the pawls and their relative arrangement with reference to the escape-wheel may be made without departing from the invention or requiring more than the exercise of mechanical skill, and such changes are within the intent and scope of my invention.

My invention as illustrated, described, and claimed herein consists, broadly, in the mounting of two pawls upon the same axis and acting in connection with a rotary escape-wheel, one of said pawls having a certain movement independent of the other and a trip upon one of the pawls adapted to engage and move the other of the pawls, the pawls being confined in their movement to one side of the axis of oscillation.

I do not claim the special arrangement or form of the teeth on the escape-wheel, nor any special arrangement of the pawls with respect to the escape-wheel, nor the manner in which the pawls shall receive the force from the escape-wheel, nor the shape of the bearing-face oi the pawls, nor the special arrangement and construction of the trip device, these features having been invented by Edwin H. Dodge, whose application was filed on the same date as that of which my within application was filed.

IVhat I claim as my invention, and desire to secure by Letters Patent, is-

1. In combination with a rotary escapewheel having d etent-teeth, a normally engaged detent-pawl with its tooth normally held in the path of movement of the detcnt-teeth on the escape-wheel, a normally disengaged pawl with a dctent-tooth, each of said pawls supported upon the same axis for movements independent of the other, and one of said. pawls adapted to be engaged and moved by the other.

2. In combination with a rotary escapewhecl having detent-teeth, a norm ally engaged detent-pawl with its tooth removably held in the path of movement of the detent-teeth on the escape-w heel, a normally disengaged pawl with a detent-tooth arranged to successively act upon the teeth engaged by the normally engaged detent-pawl, a trip device mounted on one of the pawls and arranged to engage the other pawl in its disengaging movement both of said pawls mounted upon the same support and having coincident axes of oscillation, and means for actuating the pawl bearing the trip device.

3. In combination with a rotary escapewheel having detent-teeth, a normally engaged detent-pawl with its tooth removably held in the path of movement of the detent-teeth on the escape-wheel, a normally disengaged pawl independently mounted with respect to the engaged pawl but on the same support and having a tooth arranged to successively act upon the teeth of the escape-wheel engaged by the normally engaged pawl, a trip device mounted on one of the pawls and arranged to engage the other pawl in disengaging the normally engaged pawl, both of said pawls having the same axis of oscillation and means for actuating the pawl bearing the trip device.

4. In combination with a rotary escapewheel having detent-teeth, a pivoted detentpawl with its tooth removably held in the path of movement of the detent-teeth on the escape wheel and arranged to be operated by a trip device, the trip device mounted on one of the pawls, an independent]y-pivoted disengaged pawl with a detent-tooth, both of said pawls being mounted upon the same pivot and having movements independent of each other, and means for actuating the pawl bearing the trip device.

5. In combination with a rotary escapewheel having dctent-teeth, a pair of pawls having detent-teeth, the tooth of one of said pawls normally engaging a tooth of the escape-wheel, and the tooth of the other of said pawls normally out of engagement with the teeth of the escape-wheel, said normally disengaged pawl and normally engaged pawl having coincident axes of oscillation, the tooth upon the normally disengaged pawl having engaging and disengaging movements always at one side of the axis of oscillation. 6. In combination with a rotary escapewheel having detent-teeth, a normally engaged pawl with its tooth normally in engagement with a tooth of the escape wheel, a normally disengaged pawl with a detent-tooth, means intermediate the normally disengaged

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