US788596A - Slack-adjuster. - Google Patents

Description

PATENTED MAY 2, 1905.

J. B. REED. SLACK ADJUSTER.

APPLICATION FILED DEC. 29, 1904.

2 SHEETS-SHEET l.

lNVENTOR i WTNESSES 977/4. a/n #014452 if'mm A TTOHNE Y No. 788,596. PATENTED MAY 2, 1905. J. B. REED.

SLACK ADJUSTER.

APPLIOATIOH FILED DBO. 29, 1904.

2 SHEETS-SHEET 2.

05/7265 fieed WITNESSES UVVENTUH A TTOHNE Y NlTED STATES Patented May 2, 1905.

JAMES B. REED, OF TACOMA, WASHINGTON.

SLACK-ADJUSTER.

SPECIFICATION formingpart of Letters Patent No. 788,596, dated May 2, 1905.

Application filed December 29, 1904:. Serial No. 238,843.

To all whom, it may concern:

Be it known that 1, JAMES B. REED, a citizen of the United States of America, residing at Tacoma, in the county of Pierce and State of Washington, have invented certain new and useful Improvements in Slack-Adjusters, of which the following is a specification, reference being had therein to the accompanying drawings.

This invention relates to devices for automatically taking up the slack in the brake mechanism of railroad-cars in which the airbrake is used, and has for its objects to pro duce a device which is controlled by the piston travel of the air-brake, but which operates when the brake mechanism is released; second, to locate the device so that the brake mechanism itself is not interfered with; third, to hang the device so that due allowance is made for vibration and for the lateral play necessary on account of the swinging motion of the various brake-levers; fourth, to provide a supplemental mechanism whereby the brake mechanism can quickly be made slack, so that new shoes may be readily applied, and, fifth, to have the fewest and simplest parts to my device, so that expense of construction and repair are reduced to the lowest limit. I attain these objects by the device illustrated in the accompanying drawings, in which- Figure 1 is a vertical longitudinal section on the line 1 1 in Fig. 2. Fig. 2 is a side view of the parts thereof, broken away to more clearly show the construction. Fig. 3 is a diagrammatic view showing the location of my device with regard to the brake mechanism. Figs. 4 and 5 are respectively a side view and a cross seetion of the main dog-carrier. Figs. 6 and 7 are similar views of the brake-slackening hand-lever. Figs. 8 and 9 are respectively side and front views of the rod-turning nut. Fig. 10 is a side view of the ratchetwheel, and Fig. 1.1 is a reduced plan of the main casting forming the frame and cylinder of my device.

Similar numerals of reference refer to similar parts throughout the several views.

In air-brakes operated by air-pressure a certain definite amount of air at a definite pressure is admitted to the brake-cylinder, causing the piston thereof to travel and to apply a strain to the various rods, levers, &c., so that the brake-shoes are forced against the wheels of the trucks. As the connection between the piston and the brake-shoes is direct, it follows that their respective movements are in some direct proportion to each other, so that if the mechanism has been set to give a certain travel of the piston when the brake-shoes are new then as the brakeshoes wear the piston has to travel farther than originally set. The result is that the volume of the air in the cylinder is greater and its pressure correspondingly less, and therefore the pressure of the shoes on the wheels is also less. Thus as the shoes wear the braking power of the mechanism is reduced.

InFig. 3 I have indicated the brake-cylinder 1, having the piston 2 traveling therein and connected to the floating lever 3. The fixed lever A is located, as usual, at the other end of the cylinder 1. I connect the levers 3 and 4 by a connecting-rod consisting of two end portions 5, having turnbuckles 6 secured to their ends, and of a central portion 7, screwing into the turnbuckle 6 with right and left handed screws. The piece 7 is square in cross-section except where threaded at the ends. By turning this piece 7 I alter the length of the connecting1'od between the levers 3 and 4, and thus I can compensate for any wear of the shoes without altering the travel of the piston 2 in the cylinder 1. In order to automatically turn this piece 7, I have devised the following mechanism.

A small cylinder 8 is supported as hereinafter described near the cylinder 1 and a little above the level of the connecting-rod at a point practically opposite the center of the piece 7. This cylinder 8 is connected at its rear end by means of the small pipe 9 to the inside of the cylinder 1 at a point in the side walls of said cylinder 1 beyond which it is not desirable that the piston 2 should travel.

The rod-turning nut 10, Figs. 1, 2, 8, and 9, is provided with a square central hole 25, fitting over the square part of the rod 7 sufficiently closely not to allow any appreciable play therebetween, but loosely enough to allow the rod 7 to pass freely through it. The nut 10 is formed with its outer surface in three separate parts, the two end parts 11 being of circular section, while the central part 12 is square. The size of these three parts is such that the square 12 is as large across its flat sides as the diameter of the smaller of the circular parts 11, and the other part, 11, is of greater diameter than the diagonals of the square part 12.

The ratchet-wheel 13 is constructed with radial teeth 14 and with a square central hole 15, which fits over the square part 12 of the rod-turning nut. The width of the wheel 13 is equal to the width of the part 12. Thus if the wheel 13 be turned in either direction the nut 10 and the rod 7 will turn with it.

The main dog-carrier 16 consists of a pair of flat legs or tines 17, having circular holes 18 therein of diameters equal to the diameter of the two parts 11 of the nut 10, the distance between the tines 17 being sufficiently great to span the tines of the hereinafter-described brake-slackening handlever, which themselves span the above-described ratchetwheels 13. The upper part of the carrier 16 is provided with recess 19, adapted to receive the downwardly-acting dog 20 and the spring 21. The spring 21 is very light, its only function being to make it certain that the dog 20 will be sufficientl far down to engage the teeth 14 of the w eel 13. The dog 20 consists of a guide-shank extending up into the recess 19 and pressed downward by said spring 21 and a tooth 22, which is broader than the wheel 13 or the teeth 14 and which is adapted to engage said teeth 14. The dogtooth 22 is shaped so as to slide past the teeth 14 when being pressed away from the cylinder 8 without turning the wheel 13 and so as to engage said teeth 14 when it is moved toward the cylinder 8, and thus to turn the wheel 13, nut 10, and rod 7. Carrier 16 is also provided with a pair of trunnions 23 on each side on a level with the center of the cylinder 8.

The cylinder 8 is cast with the main frame of my device. This frame consists of the cylinder 8 anda cup part 24 in front of it, the central horizontal axis of the cup being below the bottom of the cylinder 8. The cup part 24 is without any bottom, as clearly shown in Figs. 1, 2, and 11. The cup part 24 is provided with two flat horizontal extensions 26, having bolt-holes 27 therein. The frame is supported between the upper and lower sections of the straps 28 and 29, being fastened by a bolt 30 passing through one of said straps and through one of the holes 27, the other extension, 26, being between the sections of the other straps and being free to move laterally therein. The back head of the cylinder 8 is secured tightly thereto, be ing shown as screwed thereto; but any wellknown air-tight connection may be used. The air-pipe 9 is connected to the cylinder'8 through the nipple 31. The piston 32 fits in said cylinder, being preferably provided with a leather packing, such as is usually used for air-pistons. The front head of the cylinder has a vertical slot 33 therein, through which the piston-rod 34 passes, allowing it a slight vertical movement as the piston passes forward, due to the swinging motion of the carrier 16 about the central axis of the rod 7. A spiral spring 35 is compressed between the piston 32 and the front head of the cylinder 8. The piston-rod 34 is forked at its end, so as to engage the above-described trunnions 23 on the carrier 16. Thus whenever the piston 2 travels beyond the point at which the pipe 9 enters the cylinder 1 due to the wear of the brakeshoes the air-pressure therefrom passes into the cylinder 8 behind the piston 32, pushing it forward and causing the carrier 16 to rock about the center of the nut 10 and of the rod 7, the dog 20 slipping past the teeth 14 of the wheel 13. So long as the brakes are kept tight the piston 32 remains in its forward position, compressing the spring 35. As soon as the brakes are released the air-pressure is removed from the rear of the cylinder 8 and the spring 35 forces the piston back, carrying with it the carrier 16 and the dog 20 and causing the wheel 13, the nut 10, and the rod 7 to turn, thus taking up the slack in the connecting-rod due to the wear of the shoes and causing the travel of the piston 2 to be correspondingly shortened. When, however, it becomes necessary to replace the worn out brakeshoes with new ones, it is evident that the connecting-rod must be again lengthened, and I have provided for this purpose the following device: Referring to Figs. 1, 2, 6, and 7, it will be noted that the depending handle 36 is provided with a pair of tines 37, spaced so as to span the wheel 13 and to lie between the tines 17 of the carrier 16. These tines 37 are provided with elon ated holes 38, formed of a pair of upper an lower semicircles joined by straight lines, the distance between the centers of said semicircles being greater than the depth of the teeth 14 of the wheel 13. The radii of the semicircles are equal to those of the circular holes 18 in the tines 17 of the carrier 16 and to those of the two parts 11 of the nut 10. An extension 39 is provided on each tine 37 of sufficient length so that when the device is lifted up so that the nut 10 is concentric with the lower ends of the holes 38 the extensions 39 will have engaged the dog tooth 22 and have lifted it clear of the teeth 14 of the wheel 13. These extensions 39 are formedon the arc of a circle having for a center the center of the lower part of the holes 38. A recess 40 is provided in the handle 36, in which the dog 41 fits, being pressed upward by a spiral spring 42 and being limited in its upward motion by the removable pin 43. The dog 41 is shaped so as to engage the teeth 14 in the opposite direction as the dog 22 and to slip past them, as usual, when returnin Thus it is apparent that when it is desired to slacken the brakes, so as to put on new shoes or for any other purpose, all that is necessary to do is to push up the handle 36 and then swing it about the lower side of the nut 10. The extensions 39 will disengage the dog 22 from the teeth 14, while at the same time the dog 41 will engage them and is set so that the wheel 13 will be rotated in such direction as to unscrew the rod 7 from the turnbuckles 6, which themselves do not turn, being secured, as above stated, to the end parts 5 of the connecting-rod.

I have therefore invented a device whereb the brakes may be adjusted in either direction, being tightened automatically and loosened by hand.

Having now described my invention, What I claim is- 1. In a slack-adjuster for brakes, the combination with the connecting-rod joining a double brake system and formed with a central square portion screwing by right and left handed screws into the end portions thereof whereby adjustment of said connecting-rod is obtained, a nut with a square central hole therein adapted to freely slide on said square portion and having circular ends, a ratchetwheel mounted on said nut and moving therewith, a carrier having tines with holes therein adapted to engage and be supported by said circular portions of said nut and to be reciprocated thereon, a dog having a tooth engaging the teeth of said wheel and being carried by said carrier, and an air-set and spring-operated piston and rod engaging said carrier to turn said connecting-rod through said dog, wheel and nut.

2. In a slack-adjuster for brakes, having automatic air-set and spring-operated means whereby a ratchet-wheel may be turned in one direction to lessen the slack, said means including a ratchet-wheel having teeth therein and a dog having a tooth engaging but projecting on each side of said wheel-teeth, the combination of a depending hand-lever having elongated holes therein so that said lever may be raised, extensions concentric with the lower portions of said elongated holes and adapted to engage the projecting por tions of said dog-tooth and to disengage it from the teeth of said ratchet-wheel when said hand-lever is raised, and a spring-dog within said hand-lever and normally disengaged from the teeth of said ratchet-wheel but adapted to engage said teeth in the opposite direction from said first dog when said hand-lever is raised.

3. In a slack-adjuster for brakes, a square connecting rod having oppositely screwthreaded ends whereby the rotation of said connecting-rod will change the slack in the brake system, a nut riding freely on said connecting-rod and having a square hole fitting loosely over said connecting-rod and being constructed with. circular ends and a square central portion between said ends, the diameter of one of said ends being equal to or less than the distance across the flats of said square central portion and the diameter of the other end being equal to or greater than the diagonals of said square central portion,-

a ratchet-wheel mounted on the square central portion of said nut, a carrier having tines with holes therein adapted to fit over the said circular ends of said nut and to turn thereon, a dog having a tooth engaging the teeth of said wheel and being carried by said carrier, and an air-set and spring-operated piston and rod engaging said carrier to turn said connecting-rod through said dog, wheel and nut.

In testimony whereof I affix my signature in presence of two witnesses.

JAMES B. REED. Witnesses M. H. Conny, M. A. VAN House.

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