Hand Brake Mechanism

Abstract

A high power hand brake mechanism having an operating spindle, a winding drum unit, an intermediate control shaft, means for coupling the control shaft to the operating spindle, and means for coupling the winding drum unit to the control shaft.

Description

FIELD OF THE INVENTION

The present invention relates generally to hand brakes for railway cars and more particularly to operating or control mechanism for high power hand brakes wherein an effective brake applying force in excess of 6000 pounds is required.

SUMMARY OF THE INVENTION

The hand brake mechanism of the present invention includes an operating shaft rotatable by a hand wheel, a winding drum unit upon which brake chain is adapted to be wound, and an intermediate control shaft having a threaded portion.

Mounted on or carried by the control shaft are a lock ring gear, a lock ring clutch flange, a threaded lock ring which has a floating interconnection with the lock ring gear, a ratchet wheel intermediate the lock ring clutch flange and the lock ring, and pawl means having engagement with the ratchet wheel. The lock ring gear is coupled to the operating spindle, and means are provided for coupling the winding drum unit to the control shaft.

Rotation of the operating spindle in one direction effects rotation of the lock ring gear, threaded axial movement of the lock ring toward the lock ring clutch, clutching of the ratchet wheel between the lock ring clutch and the lock ring, and, consequently, rotation of the winding drum unit in a winding direction. During stepwise rotation of the operating spindle in the other direction, the ratchet wheel is alternately unclutched and clutched to thereby permit slow unwinding of the brake chain and release of the brakes without spin of the operating spindle and hand wheel.

The coupling means between the control shaft and the winding drum unit comprises a pinion rotatably mounted on the shaft and an axially shiftable jaw clutch keyed to the shaft and selectively engageable with the pinion. Operating means are provided for disengaging the jaw clutch from the pinion whereupon the pinion is free to rotate relative to the shaft for quick unwinding of the brake chain from the winding drum unit without spin of the operating spindle and hand wheel.

The hand brake mechanism herein shown and described, which includes a control shaft intermediate of the operating spindle and winding drum unit, has particular utility in applications requiring a brake setting force in excess of 6000 pounds.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a front elevational view of the hand brake mechanism of the present invention, with a portion of the hand wheel being broken away for convenience;

FIG. 2 is an enlarged sectional view, taken substantially along the line 2--2 in FIG. 1, looking in the direction indicated by the arrows;

FIG. 3 is a fragmentary sectional view, corresponding to the upper portion of FIG. 2, and illustrates the mechanism in a quick brake release position.

FIG. 4 is a sectional view, taken substantially along the line 4--4 in FIG. 2, looking in the direction indicated by the arrows;

FIG. 5 is an enlarged fragmentary sectional view, taken substantially along the line 5--5 in FIG. 1, looking in the direction indicated by the arrows; and

FIG. 6 is a fragmentary sectional view, taken substantially along the line 6--6 in FIG. 2, looking in the direction indicated by the arrows.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to FIGS. 1 and 2, a hand brake mechanism incorporating the principles of the present invention is indicated generally by the reference numeral 10. The hand brake mechanism 10 includes a housing 12 comprised of a front casing 14 suitably secured to a vertical base plate 16 adapted to be mounted to the end wall of a railway car body. The casing 14 is formed with a cut-out or opening 18 at its lower end.

Rotatably mounted in the housing 12 on vertically aligned horizontal axes are an upper operating spindle unit 20, an intermediate control shaft assembly 22, and a lower winding drum unit 24.

The operating spindle unit 20 comprises an operating spindle 26 which may be fabricated either in two sections and interconnected as shown, or in one piece if desired. The rear end of the operating spindle 26 has a steel bushing 28 press fitted thereon which is journaled in a lubricated sleeve bushing 30 press fitted in a cup-shaped retainer 32 secured in the base plate 16; the intermediate body portion of the spindle 26 is journaled in a lubricated flanged bushing 34 secured in the front casing 14; and the forward end portion of the spindle 26, which extends outwardly of the housing 12, has suitably secured thereon a hand wheel assembly 36. Formed integrally with the operating spindle 26 for rotation therewith is a pinion 38. If desired, the pinion 38 may be fabricated as a separate part and suitably secured to the operating spindle 26.

As shown in FIGS. 2 and 3, the control shaft assembly 22 includes a shaft 40 which comprises a rear end portion 42, a rear body portion 44 having radial ear portions 46, an intermediate flange or lock ring clutch 48, a forward threaded body portion 50, and a forward end portion 52. The rear end portion 42 of the shaft 40 has a steel bushing 54 press fitted thereon which is journaled in a lubricated sleeve bushing 56 press fitted in a cup-shaped retainer 58 secured in the base plate 16; while the forward end portion 52 of the shaft 40 has a steel bushing 60 press fitted thereon which is journaled in a lubricated sleeve bushing 62 press fitted in the front casing 14.

Rotatably mounted on the rear end portion 42 of the shaft 40 is a pinion 64 having a forward shoulder portion 66 which is formed with radial ear portions 68 (FIG. 6) corresponding to the ear portions 46 of the rear body portion 44 of the shaft 40. Slidably mounted on or keyed to the rear body portion 44 of the shaft 40 is an axially shiftable jaw clutch member 70 having interior recesses 72 (FIG. 6) adapted to conformably mate with the shaft ear portions 46 (FIG. 3) and the pinion ear portions 68 (FIG. 6). A coil spring 74 is interposed between the lock ring clutch flange 48 and the jaw clutch member 70 for normally biasing the latter to the position shown in FIG. 2 whereby the pinion 64 is clutched to the shaft 40 for rotation therewith.

Rotatably mounted concentric of the forward threaded body portion 50 of the shaft 40 is the flange portion 76 of a ratchet wheel 78; and threaded on the body portion 50 is a lock ring 80 having axially forwardly projecting arm members 82. Interposed between the adjacent faces of the lock ring clutch 48 and the ratchet wheel 78 is a friction disc 84, and interposed between the adjacent faces of the ratchet wheel 78 and the lock ring 80 is a friction disc 86. Mounted on the forward end portion 52 of the shaft 40 is a lock ring gear 88 which has constant meshing engagement with the operating spindle pinion 38. As shown in FIG. 4, the gear 88 is formed with axial openings 90 which receive the axial arm members 82 of the lock ring 80. This arrangement provides a floating interconnection between the lock ring 80 and the lock ring gear 88 and accommodates axial movement of the ring 80 relative to the gear 88. The hub of the lock ring gear 88 is formed with interior arcuate recesses 92, and a pin member 94 is disposed transversely through the shaft portion 52 with the end portions thereof projecting into the arcuate recesses 92 whereby to limit relative rotation between the control shaft 40 and the lock ring gear 88.

Operating means for the jaw clutch member 70, as shown in FIGS. 2, 4 and 5, comprises a secondary spindle 96 which is located intermediate of the operating spindle 26 and the control shaft 40 transversely of the latter, and which is journaled at its ends in bosses 98 formed at the sides of the front casing 14. Secured to the secondary spindle 96 is a release fork 100 having an upper flat 102 and depending arms 104 engageable at their lower ends with the rear face of the jaw clutch member 70. Located immediately above the secondary spindle 96 on one side of the operating spindle 26 is a cam shaft 106 having a cam portion 108 engageable with the upper flat 102 of the release fork 100. The rear end of the cam shaft 106 is journaled in the base plate 16, while the forward end of the cam shaft 106 is journaled in the front casing 14 and extends outwardly thereof. A release lever 110 is secured to the outer forward end of the cam shaft 106, and is provided with a flange section 112 that normally engages the outer side of the front casing 14 (FIG. 1). Associated with the ratchet wheel 78, as shown in FIGS. 4 and 6, is an upwardly extending pivotally mounted pawl 114 having a tooth portion 116. Interposed between the side of the front casing 14 and the pawl 114 is a coil spring 118 which serves to bias the pawl tooth portion 116 into engagement with the ratchet wheel 78.

The winding drum unit 24, as shown in FIGS. 2 and 4, is comprised of a hub or drum portion 120, and a spur gear portion 122 which has meshing engagement with the pinion 64 mounted on the control shaft 42. The rear end of the unit 24 has a steel bushing 124 press fitted thereon which is journaled in a lubricated sleeve bushing 126 press fitted in a cup-shaped retainer 128 secured in the base plate 16; correspondingly, the forward end of the unit 24 has a steel bushing 130 press fitted thereon which is journaled in a lubricated sleeve bushing 132 press fitted in the front casing 14. Extending axially and arcuately from the spur gear portion 122, and radially spaced from the drum portion 120, is a cam ramp sector 134. One end of the brake chain 136 is connected to the winding drum unit 24 by means of a removable pin member 138 extending radially between the cam sector 134 and the drum portion 120. The other end of the chain 136 is connected in the usual manner to the braking system of a railway car.

When the parts occupy the several positions shown in FIGS. 1 and 2, the mechanism is conditioned for winding to set the brakes. To effect brake setting the hand wheel 36 is rotated clockwise, as viewed in FIG. 1, and the operating spindle 26 and the pinion 38 are thereby correspondingly rotated. Clockwise rotation of the pinion 38 effects counterclockwise rotation of the lock ring gear 88. When the sides of the lock ring gear openings 90 engage the lock ring arm members 82, the lock ring 80 is moved rearwardly or to the left, as viewed in FIG. 2, by reason of the threaded interconnection with the control shaft 42, and the ratchet wheel 78 is clutched or clamped between the lock ring 80 and the lock ring clutch 48. Thereafter, the control shaft 42, the jaw clutch member 70, and the pinion 64 are caused to rotate with the lock ring gear 88.

Upon counterclockwise rotation of the pinion 64, the gear 122 is rotated clockwise, as viewed in FIG. 4, and the chain 136 is wound around the drum 120 to set the brakes. During winding operation, the cam ramp 134 serves to guide the chain 136 axially forwardly over the drum 120 to space the chain along the drum. Also, during the winding operation, the pawl tooth 116 rides over the teeth of the ratchet wheel 78 and prevents unwinding of the chain 136 while the brakeman shifts his grip on the hand wheel 36.

To release the brakes slowly, the hand wheel 36 is rotated a short distance counterclockwise, as viewed in FIG. 1. The operating spindle 26 and the pinion 38 are thereby correspondingly rotated counterclockwise, while the lock ring gear 88 is rotated clockwise. The ratchet wheel 78 is prevented from rotating clockwise with the lock ring gear 88 by reason of the pawl 114. As the sides of the lock ring gear openings 90 engage the lock ring arm members 82, the lock ring 80 is threaded forwardly on the control shaft 42 thereby momentarily unclutching or unclamping the ratchet wheel 78 whereby the lock ring clutch 48 is released for limited rotation to permit limited unwinding of the chain 136. As the lock ring clutch 48 rotates and catches up with the lock ring 80, the lock ring 80 is threaded rearwardly on the control shaft 42, and the ratchet wheel 78 is again clutched or clamped between the lock ring 80 and the lock ring clutch 48 to stop unwinding. When the hand wheel 36 is rotated another short distance counterclockwise, the foregoing procedure is repeated. By successively rotating the hand wheel 36 counterclockwise in incremental steps, the brakes may be slowly released, without spin of the hand wheel until the point of full release is reached.

To release the brakes quickly, the handle 110 is swung upwardly from the position shown in FIG. 1 for rotating the cam shaft 106. In this manner, the high point of the cam 108 is rotated against the flat 102 of the release fork 100 and the latter is pivoted counterclockwise from the position shown in FIG. 2 to the postion shown in FIG. 3. The jaw clutch member 70 is thus moved to the right from the position shown in FIG. 2 to the position shown in FIG. 3 and disengaged from the pinion ear portions 68 whereupon the pinion 64 is released for free rotation to permit quick rotation of the winding drum unit 24 without spin of the operating spindle 26 and hand wheel 36.

The mechanism may be restored to brake setting position by returning the handle 110 to the position shown in FIG. 1 with the flange 112 thereon in engagement with the side of the front casing 14. During return movement of the handle 110, the cam shaft 106 is rotated and the high point of the cam 108 is moved away from the flat 102 of the release fork 100. At the same time, the spring 74 returns the jaw clutch member 70 and the release fork 100 to the position shown in FIG. 2 whereupon the pinion 64 is again clutched to the control shaft 40. Slight rotation of the hand wheel 36 may be necessary to secure engagement of the pinion ear portions 68 with the jaw clutch recesses 72.

While there has been shown and described what is believed to be a preferred embodiment of the present invention, it will be understood by those skilled in the art that various rearrangements and modifications may be made therein without departing from the spirit and scope of the invention.

Claims

The invention claimed is:

1. In a hand brake mechanism having a housing, the combination of an operating spindle rotatably mounted in the housing, a shaft rotatably mounted in the housing and having a threaded portion, a lock ring gear mounted on said shaft, first means coupling said lock ring gear to said operating spindle, a lock ring clutch element on and rotatable with said shaft and having a friction face, a lock ring threaded on said threaded portion of said shaft and having a friction clutch face, a floating interconnection between said lock ring and said lock ring gear for accommodating axial movement of said lock ring relative to said lock ring gear, a ratchet wheel rotatably mounted concentric of said shaft between said friction clutch faces of said lock ring clutch element and said lock ring, pawl means mounted in the housing and having engagement with said ratchet wheel, said ratchet wheel being clutched to said shaft upon relative rotation between said shaft and said lock ring in one direction, a winding drum unit rotatably mounted in the housing, and second means selectively coupling said winding drum unit to said shaft.

2. The combination of claim 1 including interior arcuate recesses formed in said lock ring gear, and a pin member disposed transversely through said shaft with the end portions thereof projecting into said arcuate recesses whereby to limit relative rotation between said shaft and said lock ring gear.

3. The combination of claim 1 wherein said floating interconnection comprises axial openings formed in said lock ring gear, and axial arm members formed on said lock ring and extending into said axial openings of said lock ring gear.

4. The combination of claim 1 wherein said first coupling means comprises a pinion on said operating spindle and being rotatable therewith and having meshing engagement with said lock ring gear.

5. The combination of claim 1 wherein said second coupling means comprises a pinion rotatably mounted on said shaft and having meshing engagement with said winding drum unit, an axially shiftable jaw clutch element keyed to said shaft and being selectively engageable with said pinion, and operating means for moving said jaw clutch element axially to disengage the latter from said pinion.

6. The combination of claim 5 wherein said operating means comprises a secondary spindle rotatably mounted in the housing above said shaft and having a cam portion thereon, a release fork pivotally supported in the housing and being engageable by said cam portion, and said release fork having depending arms engageable with said jaw clutch element for disengaging the latter from said pinion upon rotation of said secondary spindle and said cam portion thereon.