US2100349A - Hand brake mechanism - Google Patents

Description

Nov. 30, 1937. R. c. O'CONNOR HAND BRAKE MECHANISM Filed Dec. 26, 1935 2 Sheets-Sheet l Nov. 30, 1937. R. c. OCONNOR 2,100,349

HAND BRAKE MECHANISM Filed Dec. 26, 1935 2 Sheets-Sheet 2 Pate ed Nov. 30, 1937 UNITED STATES PATENT OFFICE HAND BRAKE MECHANISM Application December 26, 1935, Serial No. 56,183

' 4 Claims.

The present invention is directed to a hand brake for railway cars, which makes provision for quickly and easily taking up the slack in the brake rigging, and the invention relates particularly to the construction and arrangement of the winding drum and its relation to the associated gear and also the pawl and ratchet mechanism and the hand lever for actuating the same.

Further objects and details will appear from a description of the invention in conjunction with the accompanying drawings, wherein- Figure 1 is a front elevation of the brake mechanism showing the hand wheel partly broken away;

Fig. 2 is a sectional elevation taken on line 2 of Fig. 1;

' Fig. 3 is a similar section taken on the same line showing a modified form of drum and brake chain; and

120 Figs. 4, 5, and 6 are details showing the pawl .25 front cover plate H), a rear wall ll, end walls I2, and an arched over top wall l3. The end walls and top wall are formed integrally with the rear wall, and the front plate is secured thereto by rivets 14 or other suitable fastening means.

.30 The front cover plate, as shown, is provided with an outwardly extending protuberance 15 in its lower portion, of arch-shaped configuration, and in the center of said protuberance the metal is outwardly bulged to afford a center boss I6 35 which receives the forward end of a gear wheel axle I! provided with a flanged head l8 which fits into a, recess l9 formed in the inwardly protruding boss on the rear wall it of the frame. The front end of the axle extends beyond the 40 plane of the inner face of the protuberant lower portion of the front plate and abuts against the inner face of the boss l6, being held in place by a cotter .pin 2| or other suitable fastening. The axle I! is surrounded by a forward bushing 22, a

45 rear bushing 23, and an intermediate bushing 24. The forward and intermediate bushings are provided at their outer ends with flanges which in conjunction abut against the ends of the hub 26 of a winding drum 2'! which is journaled upon 50 the bushings. The forward bushing 22 abuts against a bridge plate 22 which spans the space across the protruding boss I6 and has its ends integrally formed with the end walls of the frame. This arrangement brings the forward and '55 rear ends of the shaft ll into direct alignment with supports which are integrally formed in the frame so that a very rigid and rugged construction is provided and the shaft is accurately aligned within integrally formed portions of the frame.

The winding drum is provided with a bifurcated web portion 28 furnishing a groove or channel 29 flanked on either side by the smooth cylindrical faces 30 of the periphery of the drum, which configuration affords a winding surface for the alternatelinks 3| of a brake chain, the in- 10 termediate links 32 standing in transverse relation and in position to enter the center groove or channel 29 in the winding drum, so that as the chain is wound up, the alternate links will lie flatwise upon the drum surface with the inter- 15 mediate links standing edgewise within the groove.

The bushing 23 furnishes the bearing for a gear wheel 33 having a web 34, a hub 35, and a toothed rim 36.- The web is provided at a suit- 20 able point with a forwardly projecting boss 31 provided with a bore 38 to receive a headed bolt 39 which extends through a hardened collar 40 which furnishes an anchorage for the terminal link of the brake chain, the anchorage being in alignment with the plane of the groove in the winding drum.

The teeth of the gear wheel 33 mesh with pinion teeth 4| on a hand wheel shaft 42, the forward portion 43 of which projects through an aperture 30 44 in the front cover plate Ill. The forward portion 43 of the shaft is squared and tapered and terminates in a threaded stem 45 entered through a square tapered bore 46 in the hub 41 of a hand wheel 48. The hub as shown is inwardly elongated and provided with a square bore in its center portion 49 to clear the surface of the square tapered portion of the shaft. The forward end of the hub, however, is provided with a square tapered bore 50 which aligns with a square a) tapered bore 5| at the inner end of the hub, so that these two portions of the hub will come into wedging contact with the surface of the square tapered shaft 43, being held in clamped relation thereon by a nut 52 threaded onto the stem 45. 45 The shaft 42 in advance of the gear teeth 4| is enlarged to afford a ratchet wheel 53 having ratchet teeth 54 of saw-tooth formation. Between the ratchet wheel portion of the shaft and the square tapered portion, the shaft is cylindrical- 50 1y formed to afford a bearing surface 55 working within a bushing 56 which cooperates with a rear bushing 51 housed in a boss 58 in the rear wall to afford separated bearing surfaces for the hand Wheel shaft. 55

The ratchet 53 coacts with a pawl 59 having a tooth 60 positioned to engage with the abrupt faces of the ratchet teeth, and the pawl is carried by a hub 6| provided with a center axial bore 62. The hub at its inner end is provided with an inwardly protruding segmental stop 63 extending through approximately 120, the ends of which furnish stops for engagement with the ends of a segment 64 formed on or rigidly secured to a coaxial handle shaft 65 upon which the pawl hub is pivotally mounted for limited rotation. The handle shaft at its forward end carries a handle 66 which extends beyond the cover plate and frame, as shown in Fig. 1, and terminates in a weighted end portion 68. The hub BI is provided with a counterweight 69, which assists in the release of the pawl tooth 60. The relationship of the handle shaft 65 with its segment 64 to the segmental stop 63 is one which permits the handle shaft tobe turned freely through approximately 120 before the end of the segment 64 abuts against the inner end of the pawl stop 63.

The bushing 55 is carried by a boss 10 formed in a plate H which is riveted to the end walls of the frame and lies in abutting relation to the inner face of the front cover plate when the parts are assembled.

With the pawl in engagement with the ratchet teeth as in Fig. 4, the weighted handle 66 will lie in a position below the horizontal, and the contact of the forward end of the segment 64 with the outer end of the segmental stop 63 will serve to hold the pawl in engaged position. As the handle is lifted and turned beyond its vertical position, as in Fig. 5, the rear end of the segment 64 will engage with the inner end of the segmental stop 63, and further movement will cause the disengaging of the pawl tooth from the ratchet wheel.

The rearward movement of the handle 66 is limited by a tooth 12 at the base of the handle which is adapted to abut against the stop 13 on the wall of the frame. The arrangement is one which permits the handle to be drawn freely upward and past the medial position without encountering any resistance, so that it is possible toeffect av hammering action against the pawl segment 63, which may be highly desirable in cases where from freezing or other cause there is a tendency for the pawl tooth to lock with the ratchet wheel.

As shown in Fig. 6, after the pawl tooth has been carried clear of the ratchet teeth by the thrust of the handle 56, it will be swung further outwardly by the counterweight 69 until the pawl strikes the wall of the frame, which limits its outward movement.

The pawl is held in mesh with the ratchet in the on position by the weight of the release handle, and this arrangement enables a brakeman to force the pawl into engagement with the ratchet by pressing down on the handle in case the pawl should stick while in the off position. In releasing the brake, the handle is thrown about 40 past the vertical center line, and in normal operations the operator will then turn the brake wheel sufiiciently to take the strain off the pawl, which allows the handle to drop farther to the right and disengage the pawl from the ratchet. However, if difliculty is encountered in effecting the release, force may be applied to effect disengagement of the parts in the manner described.

The winding drum is separable from the gear wheel and removably mounted on the gear wheel axle, and being round affords a constant pull on the brake chain from the time the chain comes in contact with the drum surface until the full takeup of the chain is completed. The winding drum rotates independently of the gear and will start to rotate when the chain comes into contact with the winding drum, and being removable can be interchanged for other drums of different diameter to suit the amount of chain to be taken up and the power required. The free rotation of the winding drum tends to reduce friction and facilitates the full release of the brake.

The gear 33 and the winding drum 2'! in conjunction fill the space between the front and rear walls of the frame and serve to reinforce the same from within and thus prevent the front and rear walls from being bent inwardly while the cotter pin and the flanged head 18 on the shaft I! give to the shaft itself the characteristics of a rugged tie rod to prevent spreading of the walls outwardly.

The ratchet shaft with the pinion teeth thereon, as Well as the pawl and pawl release handle, are journaled in the rear wall of the frame, and the front ends are journaled in 'a plate secured to the frame in the manner described, so that with the parts thus assembled the working mechanism throughout will be accurately aligned and held against displacement irrespective of the cover plate which simply performs the function of a closure for the frame and the working parts which constitute a self-contained unit.

Fig. 3 illustrates a modified form of winding drum 14 which is provided with a wide groove 15 so that each link of the chain will fit therein as it is wound around the drum. The chain end may be suitably connected to the gear 33 as by a bolt 16.

The invention is one which permits the operating parts to be reduced in number to a minimumand to be fitted and assembled in a manner which will afford great strength and rigidity, with adequate reinforcements at all points against distortion or displacement.

Although the invention has been described with particularity as to detail, it is not the intention, unless otherwise indicated, to limit the invention strictly to the mechanism in the form shown, since modifications therein may be made without departing from the spirit of the invention.

I claim:

1. In hand brake mechanism, the combination of a frame provided with a removable cover plate, a gear shaft extending transversely and supported within the frame, a gear wheel, and a winding drum independently mounted upon the shaft and individually rotatable with respect to one another, a brake chain, anchoring means on the gear wheel for the end of the brake chain in position to carry the chain around the drum, and a hand operated gear mechanism for operating the gear wheel.

2. In hand brake mechanism, the combination of a frame provided with a removable cover plate, a gear shaft extending transversely and supported at its front and rear ends within integrally formed portions of the frame, a gear wheel, and a winding drum independently mounted upon the shaft and individually rotatable with respect to one another, a brake chain, anchoring means on the gear wheel for the end of the brake chain in position to carry the chain around the drum, and a hand operated gear 'mechanism for operating the gear wheel.

tion of a frame having an integrally formed rear wall and end Walls with an integrally formed bridge plate extending across the front of the frame between the end walls, a gear wheel shaft supported at its ends within the rear wall and the bridge plate and provided with removable means for preventing longitudinal movement of the shaft within its mountings, a gear wheel, and a separate winding drum mounted upon the shaft and independently rotatable with respect to one another, a brake chain having its end anchored to the gear wheel and adapted to be carried around the winding drum by the rotation of the gear wheel, a front cover plate secured to the frame and overlying the bridge plate and the end of the gear wheel shaft, and a. hand wheel and gear teeth in mesh with the teeth of the gear wheel.

4. In hand brake mechanism, the combination of a frame having an integrally formed rear wall and end walls with an integrally formed bridge plate extending across the front of the frame between the end walls, a gear wheel shaft removably supported at its ends within the rear wall and the bridge plate and provided with removable means for preventing longitudinal movement, a gear wheel and a winding drum independently mounted upon the shaft and freely rotatable with respect to one another, a brake chain having its end anchored in position to permit it to be carried around the winding drum by the rotation of the gear wheel, a front cover plate removably secured to the frame and overlying the bridge plate and the end of the shaft, and a hand wheel and gear teeth in mesh with the teeth of the gear wheel.

RAYMOND C. OCONNOR.

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