US468911A - Ratchet-brace - Google Patents

Description

(No Model.) I

1 G. L. HOLT.

I RATGHET BRAGE. v No. 468,911. Patented Peb.,16, 1892.

[nuen 0r.' 7 a 2 e e v i P UNITED f STATES PATENT OFFICE.

GARDNER L. HOLT, or SPRINGFIELD, MASSAcEUSETTS.

RATCHET-BRACE.

SPECIFICATION forming part of Letters Patent No. 468,911, dated February 16, 1892. Application filed June 5,1890- Serial No. 354,310. (No model.)

, ings, forming part thereof.

' brace embodying my invention.

My invention relates to that class of bit braces known as ratchet-braces, in which means are provided for causing the bit-carrying head to revolve with the brace in either direction, as may be desired; and the object of the invention is to improve the construction of such braces in such manner as to increase the strength of the engagement of the pawls with the ratchet, to prevent lost motion between said parts, and to augment the compactness and efficiency of the means to retracting the pawls.

To these ends my invention consists in the ratchet-brace constructed and operating as hereinafter fully described, and particularly pointed out in the claims.

Referring to the drawings, in which like letters designate like parts, in the several views, Figure 1 is a side elevation of a ratchet- Fig. 2 is a plan view, partly in section, showing one of the pawls in engagement with the ratchet. Fig. 3 is a similar view showing the opposite pawl in engagement with the ratchet. Fig. 4 is a plan view showing both pawls in engagement with the ratchet. Fig. 5 is a side elevation of the parts shown in Fig. 4, the pawlretracting sleeve being shown in vertical section. Figs. 6, 7, and 8 are respectively a cross-section, vertical section, and side elevation of the pawl-retracting sleeve.

The letter a designates the body of the brace, which terminates at its lower end in hub 17; c, the bit-carrying head, journaled at its upper end in said hub b, and cl the ratchetwheel located within a recess in hub 17 and rigidly secured to said head 0, said wheel having its periphery knurled or milled to form shallow V.-shaped teeth, as shown; also, 10-- cated within the recess in hub 19 are the two pawls ee, pivotally mounted substantially midway between their ends upon pins 8 whereby they are adapted to be moved to throw one end thereof into and out of engagement with said ratchet-wheel. The outer ends of said pawls are beveled to form a point extending parallel with the teeth on the ratchet-wheel, and'at their inner ends they are provided with sockets upon their adjacent sides to receive the ends of a coil-spring f, which presses said inner ends away from each other, and upon their outer sides with transverse grooves or recesses e to receive the flange on the retracting-sleeve, as will be presently described. The spring f normally holds the outer ends of both of said pawls in engagement with the teeth of the ratchetwheel, as represented in Fig. 4, in which po sition the bit is positively driven in both directionsby the brace. .The inner ends of the pawls are slightly rounded, as shown, and

said ends normally bear lightly against the rear end wall of the recess in the hub 11, so that while said pawls have freedom of movement upon their pivots whenever power is applied to the brace to overcome resistance of the bit the pressure upon the pawl or pawls is exerted directly by said wall of the recess in the hub, thereby taking the strain from the pins e and forming avery strong and d11- rable construction. The pivot-pins 6 moreover, are so located that the point at which either of the pawls engages the ratchet-wheel will lie but slightly outside of a straight line drawn between its pin 6 and the center of the ratchet-wheel, which lines are represented by broken lines in Figs. 2, 3, and 4, and consequently the pressure exerted upon the pawl when power is applied to the brace tends to force its pointed end toward the bottom of the tooth of the ratchet-wheel, against which it bears and toward the center of said wheel in such manner as to increase the tightness of its hold upon the wheel and obviate all possibility of slipping. I thus secure an important advantage over constructions in which the pressure exerted against the ratchet-wheel by the pawl is tangential to the former, not only by way of increased security against slipping, but also by reason of the fact that I am enabled to employ a ratchet-Wheel having very fine teeth and thereby prevent, practically, any lost motion between the pawls and wheel, a result which enablesthe brace to be successfully used in positions where but a slight movement of the crank is possible fconsists of a sleeve 9, revolubly mounted upon hub 1) adjacent to the rear or inner ends of thepawls. Said sleeve is provided at each end with an inwardly-projecting annular flange g, of which flanges the one at the rear end bears upon the hub 12 and the one at the front end enters the recesses c in the outer side of the pawls, as shown, said latter flange having therein the notch or open The inner surface of the -sleeve'be-j ing 9 tween said flanges is concentric for the greater portion of its length; but between the points 6 6 (see Fig. 6) itiis formed into the cam-surface 9?, which is locateddiametrically opposite to the'notch 9 It will be obvious'that a partial revolution can be .imparted to said sleeve in either. direction without affecting thepawls, and that bycontinuing. said movement .until the cam-surface g is broughtto bear against either of the pawls the rear end of the latter will be forced in- W-ardly, thereby moving its front .endioutwardly and out of engagement with the ratchet-wheel.

A stop-pin h, seated in hub b, projects between .the 'flanges of said sleeve, and by. engaging the cam-surface g prevents the entire revolution .of the sleeve. The periphery of the sleeve is preferablyimilled at itsedges, as shown, tofacilitate turning it. Thei'flanges on the sleeve protect the interiorv of the latter from dirt, .thus insuring .the smooth and easy action .oflthe cam-surface upon the pawls and preventing undue wear of said parts, and the flangeat'. thef'ront end also serves to-retain the sleeve in its operative position by entering the recesses in the pawls without the aid of other devices. "I thus avoid the use ofstop-pins or other; projecting means for prevent-ingendwise movement of. thefsleeve, which, besidesdetracting from the appearance of the brace,-are liable to injure the hands of. the user. The sleeve is. placed in, position by forcing the outer ends of both ,pav'vls outwardly until their inner ends .are'moved within the circumferential plane of huh I) and then moving the sleeve outwardly until its. 'front 'fiange'overl-ies the recesses in said pawls, the notch/g in said "flange permitting it to pass the stop-pink, and finally releasing the outer ends of the pawls, whereupon spring f forces their inner ends awayfrom .each other to the position shown in the drawings. The cam-surface g and the notch g being oppositelylocated, as described, wheneversaid notch is in register with stop-pin h the rear ends of the pawls are in engagement with the front flange on the sleeve, so .that accidental endwise movement of the. sleeve is rendered impossible.

Theoperationof the ratchet-brace thus constructed willbe obvious from the forego ingdescription. vW Vhen the parts are in the position represented'in Fig. :1, the crank of the brace and head 0 will revolve in unison likethose of an ordinary brace, while by turning sleeve 9 as far as it will go in either direction from the position shown in said figure either of the pawls can be moved to the position shown in Figs. 2 and 3, in which it is out of engagement with .the ratchet-wheel, thus providing for a positive movement of the bit inbut one direction.

The peculiar biting action of the pawls upon the ratchet wheel hereinbefore described would effectually prevent slipping thereof upon said wheelif thesurface of the latter were merely roughened slightly instead of being provided with teeth; but I prefer the construction shown, as it improves the appearance of the wheel and prevents uneven wear of the surface thereofby the pa-wls.

'An important feature of the construction herein-shownand described is the fact that the operating cam and its stopare wholly concealed from view, thereby greatlyaugmentin g the pleasing appearance of the brace and preventing said parts. frombeing a source of injury and annoyanccto. theuser ofthe tool.

Having thus 'fullydescribed my invention, what '1 claim, and desire to secureby Letters Patent, is

1. In a ratchet-brace, the combinatiomwith the bit-carrying head, of'a ratchet-wheel rigidly secured thereto, said wheel being; provided with shallow-Nrshaped teeth,- t-wo pawls pivoted at .a point substantially midway between theiren (ls to the frame of the brace and adapted to engage the teeth of said wheel at their front end, said pawls having in the outer side andnear .the rear end thereof atransverse groove or recess, aspring pressing the rear ends of said pawls in opposite directions,

and av sleeve revolubly mounted upon the frame,;said sleeve having at v the front end thereof an inwardly-extendin gannular flange which projectswithin thegrooves or recesses in said pawls and having upon its inner side a cam-surface adapted by its engagement with the rear end of eitherof said pawls to disengage the front end thereof from the ratchetwheel, substantially as set forth.

2. "In the: ratchet-brace herein described, the combination, with the ratchet=wheel,.the pivoted-pawls, and the spring pressing the rear ends of said pawls'in opposite directions, of a retracting-sleeve having at the ends thereof inwardly-extendingann ular flanges, one of which flanges enters a transverse groove or recess in .the outer side and at the rear end of each of the pawls, said-sleeve also having upon the inner side thereof between said flanges: a cam-surface,"substantially asdescribed, and-a fixed stop projecting between the flanges on said sleeve and adapted by its engagement with said cam-surface-tolimit the revolving movement of the sleeve, substantially as set forth.

3. .Theratchet-brace herein described, comprising, in combination, the body portion a, terminating at its lower end inthe-recessed.

hub 12, bit-carrying head 0, journaled at its pressing the rear ends of said paw1s away upper end in said hub, ratchet-wheel d, .rigfromeach other, and retracting-sleeve 9, ar- 10 idly secured to said head within the recess in ranged and operating substantially as and said hub, pawls e e, pivotally mounted within for the purpose set forth.

the recess in said hub, said pawls having their GARDNER L. HOLT. front ends adapted to engage said ratchet- Vitnesses: Wheel and having their rear ends abutting W. HOBAPMAN,

against the end wall of said recess, spring f, J. E. CHAPMAN.

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