US2850129A - Clutch for a brace - Google Patents

Description

p 2, 1958 P. s. MORGAN 2,850,129

CLUTCH FOR A BRACE Filed July 26, 1952 rates atent Office 2,850,129 Patented Sept. 2, 1958 CLUTCH FOR A BRACE Porter S. Morgan, Westport, Conn., assignor to I. 'L.

This invention relates to bit stocks or braces, and more particularly to such devices in which unidirectional clutch means are provided, as for instance by a ratchet.

An object of the invention is to provide an improved brace having a unidirectional drive or ratchet action associated with the chuck, which is characterized by virtually no back drag.

Another object of the invention is to provide an improved brace having a unidirectional drive associated with the clutch, which is characterized by virtually no lost motion.

A still further object of the invention is to provide an improved brace having unidirectional drive associated with the chuck, which is characterized by a continuous or smooth gripping action as distinguished from an intermittent or stepped action.

Still another object of the invention is to provide an improved brace according to the foregoing, in which the unidirectional clutch action may be easily and quickly made to operate in either of reverse directions.

A feature of the invention is the provision of an improved brace as above set forth, which is simple and sturdy in its construction and reliable in use, being constructed of relatively few parts and being economical to fabricate.

Other features and advantages will hereinafter appear.

In the accompanying drawings:

Figure 1 is a side elevational view of an improved brace made in accordance with the invention.

Fig. '2 is a fragmentary horizontal section, enlarged, taken on line 2-2 of Fig. 1.

Fig. 3 is a fragmentary vertical section taken on line 33 of Fig. 2.

Fig. 4 is a fragmentary vertical section taken approximately on line 44 of Fig. 2, the locking members being shown in elevation.

Fig. 5 is a view partly in elevation and partly in vertical section taken on line 55 of Fig. 3.

Fig. 6 is a view like Fig. 4, but reduced in size and showing the parts in position to effect a unidirectional drive.

Referring to Fig. 1 the improved brace of this invention comprises a handle or frame part 10 formed with the usual crank shape, having at one end a kob 11 and, on the crank portion a hand grip 12. At its other end the handle part 10 has the usual type of chuck 13 adapted .to mount bits and the like.

In accordance with the present invention an improved, stepless, smooth-acting unidirectional clutch mechanism is provided between the chuck 13 and the handle part 10, enabling the brace to be used in the manner of a ratchet brace but without back drag or lost motion being present. The improved unidirectional drive is further characterized by an advantageous stepless action, by few and simple parts, and by convenience of operation.

Referring to Figs. 1, 2 and 3, this improved drive comprises a casing or fitting 14 which I hereinafter term .a pin 17 passing through said part.

- with the fitting 14.

an angle fitting, in which the chuck 13 is rotatably mounted and to which the handle part 10 is rigidly secured. The angle fitting 14 comprises a body having a laterally extending portion 15 provided with a bore 16 in which the handle part 10 is secured, as by means of The angle fitting 1 has a main body portion 18 which is somewhat barrel-like in its shape, having a vertical bore 19 extending completely through it.

The chuck 13 has a shank or shaft 20 which is preferably provided with knurling 21, and which has an annular groove 22 intermediate its ends. On the knurled portions 21 of the shaft 20 spur gears 23 are carried,

meshing with a pinion gear 24 rotatable in a small vertical bore 25 in the body portion 18 of the fitting, ,Fig. 2.

Theshank or shaft 20 is retained in the fitting 141by a crescent-shaped member 26 which is received in the groove 22 of the shaft, said member being secured to the fitting 14 as by drive pins 27.

Top and bottom plates 28 and 29 respectively are carried .by the fitting 14, enclosing the shaft 20, gears Y23 and pinion .24, the bottom plate having an opening 30 through which the shaft 20 extends. As shown in .Fig. .3 the fitting .14, at its upper and lower portions, is

preferably laid over the top and bottom plates 28 and .29 to secure these in place.

The top plate 28 is provided with a depressed portion 31 forengagement with the end of the shaft 30 to act as a thrust bearing therefor. 1

To effect aunidirectional clutch or braking action I provide a friction brake wheel '32 which is carried by and rotatable with the pinion 24. The brake wheel '32 may have a bore conforming to the cross sectional shape .of the pinion .24 to enable the pinion to be passed force which is-applied to the brake wheel 32 will result in the chuck 13 tending to lock and therefore to turn I preferablymake the gears 23 of substantially larger pitch diameter than the pinion 24, and make the friction brake whee1.32 of larger diameter than the pinion '24, and thus obtain a desirable mechanical advantage whereby a relatively small braking force applied to the brake wheel 32 will result in a much greater force beingrequired on the chuck 13 if it is to be turned with respect to the fitting 14.

For the purpose of selectively unidirectionally locking the brake wheel 32 against movement in one direction or the other I provide locking members 34 in the lateral extension 15 of the fitting 14, said members beingpreferably substantially cylindrical in shape and being carried in a cylindrical bore 35 which extends horizontally in the extension 15 and communicates with the clearance spaces 33 of the fitting. The locking members 34 have bores 34a accommodating a helical compression spring 34b by which they are yieldably urged apart or away from each other, and said members have milled cuts 37 providing braking surfaces for engagement with the periphery of the brake wheel 32. The locking members 34 are normally held in closely spacpd or juxtaposed positions as shown in Fig. 2, wherein the braking surfaces thereof are engageable with the periphery of the brake wheel 32, by a collar 36 which is rotatable on the extension 15 of the fitting and which encircles the locking members 34.

Referring to Figs. 4 and 6 the collar 36 has a portion of its bore relieved, providing a clearance space 38 having camming surfaces 39 at its ends. The purpose of this clearance space is to enable one or the other of the locking members to be moved outward by the spring 34b, thereby to disengage the brake wheel 32 and relinquish all control thereover.

As shown in Fig. 6 the collar 36 has been shifted counterclockwise from the position of Fig. 4, resulting in the rightmost locking member 34 shifting outward to separate its brake surface from the brake wheel 32.

A detent means is provided in conjunction with the collar 36, said detent means comprising the pin 17, comprising notches 40 in the outer edge of the collar 36, and comprising a concave-convex spring washer 41 disposed between the collar and the body portion of the fitting. It will be understood that this detent means will retain the collar 36 in either of three positions in which it is placed. One such position is shown in Figs. 2 and 4, wherein both of the locking members 34 are brought substantially in contact with the brake wheel 32. Another position of the collar 36 is shown in Fig. 6, wherein the rightmost locking member may occupy an outwardly shifted position. The third position of the collar 36 is opposite to that shown in Fig. 6, and enables the leftmost locking member 34 to occupy an outwardly shifted position.

The braking action on the brake wheel 32 is effected as follows: When the collar 36 is in the position shown in Figs. 2 and 4, the brake surfaces 37 of the locking members 34 will be engageable with spaced points on the periphery of the brake wheel 32, which points define a small arc of said periphery. The brake wheel will also engage the shaft 20, or more properly the bottom of the groove 22 in the shaft 20, and this point of engagement will be directly opposite the are bounded by the points of engagement of the brake wheel with the locking members 34. A wedging action is thus obtained, and if for example the shaft 20 should experience clockwise turning force with respect to the fitting 14, as viewed in Fig. 2, it will because of the meshing engagement of the gears shift the brake wheel 32 downward and wedge the wheel between the shaft 20 and the lower of the two brake members 34. counterclockwise turning applied to the shaft 20 will in a similar manner result in the brake wheel 32 being shifted upward and being wedged between the shaft 20 and the upper of the two locking members 34. Thus the chuck 13 will be locked to the handle part against relative rotation in both direc-' If new the collar 36 should be turned in one tions. direction or the other it will enable one or the other of the locking members 34 to be shifted away from the locking wheel 32, to disengage the latter. If, for example, the lower of the two locking members 34, as seen in Fig. 2, is shifted out of engagement with the locking wheel 32 the said wheel will be permitted to have free counterclockwise rotation at all times, allowing the shaft as viewed in Fig. 2 to have free clockwise rotation. Any clockwise turning force exerted on the shaft 20 will tend to shift the pinion 24 and brake wheel 32 downward and maintain the brake wheel out of wedging engagement with the shaft 20 and the upper of the locking members 34. Opposite turning force exerted on the shaft 20 will however immediately shift the pinion 34 and brake wheel 32 upward, causing the wheel to be wedged between the shaft 20 and the upper of the two locking members. Thus a unidirectional clutch action is obtained, and I have found that such action is highly desirable in a tool of the character described in that there is practically no lost motion involved at any time, inasmuch as the shifting movement experienced by the pinion 24 and brake wheel 32 is extremely slight. Moreover, when one or the other of the locking members 34 is in its outward orreleasing position, free turning of the brake wheel and pinion is permitted in the one direction without restraint, and accordingly no back drag is experienced in the operation of the brake. Thus when starting a hole with the bit, particularly if it is a small size bit, there will be no necessity to hold the chuck 13 against retrograde movement it the ratchet action is being utilized. Moreover, where space is limited, the present improved unidirectional clutch mechanism is advantageous in the elimination of a stepped movement such as is characteristic of a ratchet device having teeth. Often when employing a ratchet device in a limited space, part of the movement of the handle is lost be cause the click or pawl cannot be made to pass the next tooth of the ratchet wheel. This, however, is not experienced when using the brace of the invention, inasmuch as there is complete absence of any stepped movement in the unidirectional drive.

The bearing for the shaft 20 in the fitting 14 is provided by the engagement of the crests of the teeth of the gears 23 with the bore 19. Likewise engagement of the pinion 24 with the bore 25 provides sufiicient bearing for the pinion and the brake wheel 32.

I prefer to effect the assembly of the device as follows: With the parts all disassembled, the bottom plate 29 is assembled and secured to the fitting 14. The brake wheel 32 is then slipped into the bore 19 from the top and shifted edgewise into the clearance spaces 33 provided in the extension 15. The brake wheel is shifted until it passes into the transverse bore 35 as far as it will go. The shaft 20 is passed up through the bottom plate 29, and the lower gear 23 pressed on the shaft. The crescent-shaped retainer member 26 is then put in place and secured by the drive pins 27. The upper gear 23 is then pressed on the shaft 20, the pinion 24 dropped into place, passing through the brake wheel 32, whereupon the top plate 28 is positioned and secured to the fitting 14. The locking members 34 may then be inserted in the bore 35, together with the spring 36. The washer 41 and collar 36 are placed on the extension 15, the handle part 10 inserted in the extension 15 and the pin 17 driven into place.

Variations and modifications may be made within the scope of the claims and portions of the improvements may be used without others.

I claim:

1. A unidirectional drive mechanism for use in a brace or the like, comprising a turnable driving part; a shaft which is to be driven, rotatably mounted on said driving part; a friction brake wheel rotatably mounted on the driving part; a driving connection between the shaft and brake wheel, causing turning of the wheel when the shaft is turned with respect to said driving part; normally operative releasable friction braking means to lock the friction wheel against turning solely in one direction; and manually operable means for rendering said braking means inoperative, thereby to provide for free turning of the brake wheel in said one direction, said driving connection comprising step-up gearing between the shaft and the brake wheel causing angular movements of the latter to be greater than those of the shaft.

2. The invention as defined in claim 1 in which the braking means includes a portion of said shaft, having a surface engageable with the friction wheel, said shaft portion when engaged under pressure tending to lock the wheel against turning.

3. The invention as defined in claim 1 in which the driving connection includes a large gear secured to the driven shaft, and a small gear secured to the brake wheel and meshing with the large gear, and in which the brake Wheel is of larger diameter than the small gear, providing a mechanical advantage in the transmission of force to the driven shaft when braking force is applied to the brake wheel.

4. In combination, a handle part; a driven member rotatably mounted on said part; a friction brake wheel rotatably mounted on said part; a mechanical advantage stepup gear driving connection between the driven member and brake wheel, causing turning of the wheel when the handle part is turned with respect to the driven member but at a greater angular speed; normally operative releasable friction braking means to lock the friction wheel against turning in one direction; normally operative releasable friction braking means to lock the friction wheel against turning in the other direction; and manually operable means for selectively rendering inoperative one or the other of said braking means, thereby to selectively provide for free turning of the brake wheel in one direction or the other and Wedging of the wheel against turning in the opposite direction.

5. The invention as defined in claim 4 in which the braking means include a pair of aligned members movable on said handle part toward and away from each other along a path generally tangential to said brake wheel, said members having brake surfaces engageable with said wheel, and in which the manually operable means includes a rotatable collar on the handle part, extending around the aligned members and having cam means engageable with the members to control the positions thereof. 7

6. In a device of the character described, an angle fitting; a driven member rotatably mounted on the fitting; a first gear within the fitting, secured to the driven member to turn therewith; a second gear rotatable in the fitting, meshing with the first gear; a friction brake wheel secured to the second gear to turn therewith when the driven member is turned with respect to the fitting; a

pair of members having brake surfaces for engagement with the brake wheel, said members being movable in the fitting between operative positions wherein the brake surfaces thereof engage adjacent points on the periphery of the brake wheel bounding a small arc, and positions wherein they disengage the wheel; means providing a brake surface in the fitting for engagement with the periphery of the brake wheel opposite to the said bounded are, enabling said wheel to be wedged between said means and either of said members to prevent its rotation; and manually operable means for selectively holding one or the other of said members in its operative position, thereby to selectively provide for free turning of the brake wheel in one direction or the other and wedging of the wheel against turning in the opposite directions.

References Cited in the file of this patent UNITED STATES PATENTS 803,669 Cook Nov. 7, 1905 1,090,578 Smythe Mar. 17, 1928 1,388,836 Ripsch et al Aug. 23, 1921 1,816,295 Pitter July 28, 1931 1,845,667 Johnson Feb. 16, 1932 2,331,339 Morris Oct. 12, 1943 2,539,861 Robinson Jan. 30, 1951 2,578,686 Fish Dec. 18, 1951 FOREIGN PATENTS 635,153 France Mar. 9, 1928

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