US3679028A

US3679028A - Multiple unit brake

Info

Publication number: US3679028A
Application number: US96778A
Authority: US
Inventors: Harry W Mulcahy; Eldon W Bushnell; John W Kaim
Original assignee: Amsted Industries Inc
Current assignee: Amsted Industries Inc
Priority date: 1970-12-10
Filing date: 1970-12-10
Publication date: 1972-07-25
Anticipated expiration: 1989-07-25

Abstract

A live and dead lever are mounted on one side of a railway truck and pivotally connected at their lower ends to an automatic double-acting slack adjuster. The upper end of the dead lever is pivotally connected to the truck while the upper end of the live lever is pivotally connected to a piston engaged in a cylinder. A trigger lever is located proximate the live lever and pivotally connected at its lower end to a trigger of the slack adjuster. Two braking devices, each engageable with a wheel used to support the truck, are pivotally connected to the levers intermediate their ends. One device is connected to the dead lever and one device is connected to both the live lever and the trigger lever. Mounted proximate the upper end of the trigger lever is an abutment bracket which is used to retard movement of the end beyond a given point.

Description

United States Patent Mulcahy et al.

[ MULTIPLE UNIT BRAKE [72] Inventors: Harry W. Mulcahy; Eldon W. Bushnell, both of Lansing; John W. Kaim, Chicago,

all of I11.

[73] Assignee: AMSTED Industries Incorporated,

Chicago, Ill.

[22] Filed: Dec. 10, 1970 [21] Appl. No.: 96,778

[52] U.S. Cl ..l88/202, 188/52 [51] Int. Cl ..Fl6d 65/56 [58] Field of Search ..188/52, 197, 198, I99, 200,

[56] References Cited UNITED STATES PATENTS 2,994,409 8/1961 Simanek ..188/52 3,177,985 4/1965 Rauglas ..188/202 PL R 51 July 25, 1972 Primary Examiner-Evon C. Blunk Assistant Examiner-Johnny D. Cherry Attorney-Walter L. Schlegel, Jr. and John W. Yakimow [5 7] ABSTRACT A live and dead lever are mounted on one side of a railway truck and pivotally connected at their lower ends .to an automatic double-acting slack adjuster. The upper end of the dead lever is pivotally connected to the truck while the upper end of the live lever is pivotally connected to a piston engaged in a cylinder. A trigger lever is located proximate the live lever and pivotally connected at its lower end to a trigger of the slack adjuster. Two braking devices, each engageable with a wheel used to support the truck, are pivotally connected to the levers intermediate their ends. One device is connected to the dead lever and one device is connected to both the live lever and the trigger lever. Mounted proximate the upper end of the trigger lever is an abutment bracket which is used to retard movement of the end beyond a given point.

4 Claims, 3 Drawing Figures Patented July 25, 1972 2 Sheet -s 1 lllllll 2 Sheets-Sheet 2 Patented July 25, 1972 MULTIPLE UNIT BRAKE This invention relates to brake rigging for railway trucks.

The disclosed brake rigging is particularly adapted for railway trucks. It has the advantage of being lighter in weight and lower in cost than most of the currently employed clasp and unit brake arrangements. The rigging may be easily and quickly maintained from the side of the truck.

Because of the slack adjuster employed and the novel adjustment linkage, the proper release clearance will be automatically set during the first brake application after the brake shoes or the wheels are replaced.

The rigging maintains a constant piston travel resulting in a relatively constant braking force. When large amounts of wear occurs such as when snow brakes are used, the slack adjuster automatically compensates and returns the piston travel to its predetermined setting during the next brake application.

In brief, the present invention comprises two support brackets that may be mounted on a railway truck. A cylinder is attached to one of the brackets and has a piston pivotally connected to the upper end of a live lever. The lower end of the live liver is attached to one end of a known automatic double-acting slack adjuster. A dead lever has its upper end pivotally connected to the other bracket and its lower end pivotally connected to the other end of the slack adjuster. A trigger lever located adjacent the liver lever is pivotally connected at its lower end to the trigger of the slack adjuster. A brake head and shoe assembly is pivotally connected to the trigger and live lever intermediate their ends and a second brake head and shoe assembly is pivotally connected to the dead lever intermediate its ends. The shoes are engageable with the treads of the wheels supporting the truck. An abutment bracket is provided adjacent the upper end of the trigger lever to retard movement of the upper end at a given location during movement of the piston. The trigger lever pivots about the brake head and shoe assembly moving the trigger relative to the slack adjuster body causing the slack adjuster to retain its length or permitting it to shorten or to lengthen, depending upon the forces applied, the position of the trigger, and the clearance between the brake shoes and the wheels.

FIG. 1 is a semi-schematic side elevational view illustrating brake rigging which may be mounted upon a railway truck;

FIG. 2 is an end elevational view illustrating the brake rigging at the live lever; and

FIG. 3 is an end elevational view illustrating the brake rigging at the dead lever.

The figures illustrate portions of railway wheels and 12 which are used to support a railway truck (not illustrated) in a known manner. Brake rigging 14 is mounted on the truck and includes

support brackets

16 and 18.

An air cylinder 20 is mounted on bracket 16. The cylinder 20 is adapted to receive a piston 22 which is pivotally connected to the upper end of a live brake lever 24. A known automatic double-acting slack adjuster 26, similar to the ones i]- lustrated in U.S. letters Pat. Nos. 3,298,475, 3,406,794 and 3,442,358, incorporated herein by reference, is pivotally connected to the lower end of live lever 24 and to the lower end of a dead brake lever 28. The upper end of dead lever 28 is pivotally connected to bracket 18.

The live and

dead levers

24 and 28 are respectively pivotally connected intermediate their ends to brake

heads

30 and 32.

Brake shoes 34 and 36 are secured to

brake heads

30 and 32 and are adapted to be engaged with the

wheels

10 and 12. Spaced hanger levers 38 and 40 are mounted on each side of live lever 24 and dead lever 28. The hanger levers 38 and 40 are pivotally connected at their upper ends to the

brackets

16 and 18 and at their lower ends to the

brake heads

30 and 32.

The live lever 24 may extend above piston 22 and be adapted to be connected with a known hand brake arrangement. For simplicity, the hand brake arrangement is represented by pull rod 42.

A single trigger lever 44 is pivotally connected intermediate its ends to brake head 30. The lower end of the trigger lever 44 is pivotally connected to the trigger 46 of the automatic double-acting slack adjuster 26. An abutment bracket 48 is secured to bracket 16 proximate the upper end of trigger lever 44. Adjustment means, illustrated as a bolt-nut combination 49 in a slot 50 is provided to locate the abutment bracket 48 relative to bracket 16. The abutment bracket 48 is provided to resist movement of the top of trigger lever 44 beyond a given point.

In operation, a force is exerted by piston 22 against the upper end of live lever 24 moving the brake shoes 34 and 36 respectively into contact with

wheels

10 and 12. At the moment of braking, the slack adjuster 26 is rigid.

It is understood that the slack adjuster 26 is designed so that if trigger 46 does not move, relative to the slack adjuster, the slack adjuster will shorten under a compressive load but will not lengthen. Furthermore, a predetermined movement of trigger 46 relative to slack adjuster 26 permits the slack adjuster to lengthen when required. Movement of trigger 46, in excess of the aforementioned predetermined amount locks the slack adjuster 26 making it a rigid unit in compression. During a brake application, piston 22 moves in a brake applying direction, the upper end of trigger lever 44 contacts abutment bracket 48 moving trigger 46 relative to slack adjuster 26 causing the internal mechanism in the slack adjuster to unlock allowing the slack adjuster to lengthen if the brake shoes are not engaged with the wheels.

As piston 22 reaches its predetermined travel, trigger 46 has moved relative to slack adjuster 26 sufficiently to lock the slack adjuster to prevent shortening under the compressive load of the brake application.

If the distance traveled by piston 22 is less than desired,

trigger lever 44 will be out of contact with abutment bracket 48 at the time brake shoes 34 and 36 begin to engage

wheels

10 and 12. During such engagement compressional forces are exerted on the ends of slack adjuster 26. Because trigger 46 has not moved and due to the design of the internal mechanism of slack adjuster 26, slack adjuster 26 will shorten in length thereby forcing the piston 22 to move further away from cylinder 20 to engage the brake shoes 34 and 36. A point will be reached at which contact will eventually be made between the upper end of trigger lever 44 .and abutment bracket 48 causing trigger 46 to move away from slack ad- .juster 26. A predetermined amount of trigger movement will cause the slack adjuster 26 to lock and prevent further shorteningl The slack adjuster 26 will thereafter be rigid during braking.

From the foregoing, and the information incorporated by reference, it can readily be seen that by adjusting the location of abutment bracket 48 any desired piston travel may, be achieved. It may be further appreciated that trigger lever 44 may be located proximate either wheel 10 or wheel 12 with appropriate positioning of the slack adjuster 26.

What is claimed is:

1. In a braking system for a railway truck supported upon wheels, the braking system having brake'devices adapted to be frictionally engaged with the treads of the wheels, actuating means having a movable member, a slack adjuster having first and second ends which ,are movable toward and away from each other and which may be locked in a given position relative to each other, and a trigger mounted on the slack adjuster for locking the ends relative to each other and for permitting movement of the ends, the trigger being actuated in response to the movement of a trigger lever, the improvement comprismg:

a live brake lever located on the side of the truck and pivotally connected to a brake device adapted to be engaged with a first wheel, the live brake lever having an upper end and a lower end, the upper end being pivotally connected to the movable member of the actuating means and the lower end being pivotally connected to the first end of the slack adjuster; a dead brake lever located on the side of the truck and pivotally connected to a brake device adapted to be engaged with a second wheel, the dead brake lever having an upper end and a lower end, the upper end being pivotally connected to the truck and the lower end being pivotally connected to the second end of the slack adjuster;

a trigger lever pivotally connected to one of the brake devices, the trigger lever having an upper end and a lower end, the lower end being pivotally connected to the trigger; and

abutment means located proximate the upper end of the trigger lever to contact the upper end of the trigger lever during movement of the brake levers and brake devices to move the lower end of the trigger lever and thereby actuate the trigger.

2. In a brake arrangement for a railway vehicle truck having a frame and a pair of supporting wheel and axle assemblies, the combination comprising friction means disposed for engagement with respective assemblies, power means having a pair of relatively movable parts one of which is pivoted to the frame, a pair of levers pivoted intermediate their ends to respective friction means, one of said levers pivoted at one end to the other of said movable parts of said power means, the other of said levers pivoted at one end to the frame, and slack adjusting means interconnecting the other ends of said levers.

3. The invention of claim 2, further comprising trigger means associated with said slack adjusting means for selectively locking and unlocking same so as to control slack adjustment.

4. The invention of claim 3, wherein said trigger means comprises a trigger supported by said slack adjusting means so as to control said slack adjustment, a trigger lever pivoted at one end to said trigger and pivoted intermediate its ends to one of said friction means, and abutment means supported by the frame proximate the other end of said trigger lever for en gagement therewith upon activation of said power means.

Claims

1. In a braking system for a railway truck supported upon wheels, the braking system having brake devices adapted to be frictionally engaged with the treads of the wheels, actuating means having a movable member, a slack adjuster having first and second ends which are movable toward and away from each other and which may be locked in a given position relative to each other, and a trigger mounted on the slack adjuster for locking the ends relative to each other and for permitting movement of the ends, the trigger being actuated in response to the movement of a trigger lever, the improvement comprising: a live brake lever located on the side of the truck and pivotally connected to a brake device adapted to be engaged with a first wheel, the live brake lever having an upper end and a lower end, the upper end being pivotally connected to the movable member of the actuating means and the lower end being pivotally connected to the first end of the slack adjuster; a dead brake lever located on the side of the truck and pivotally connected to a brake device adapted to be engaged with a second wheel, the dead brake lever having an upper end and a lower end, the upper end being pivotally connected to the truck and the lower end being pivotally connected to the second end of the slack adjuster; a trigger lever pivotally connected to one of the brake devices, the trigger lever having an upper end and a lower end, the lower end being pivotally connected to the trigger; and abutment means located proximate the upper end of the trigger lever to contact the upper end of the trigger lever during movement of the brake levers and brake devices to move the lower end of the trigger lever and thereby actuate the trigger.

4. The invention of claim 3, wherein said trigger means comprises a trigger supported by said slack adjusting means so as to control said slack adjustment, a trigger lever pivoted at one end to said trigger and pivoted intermediate its ends to one of said friction means, and abutment means supported by the frame proximate the other end of said trigger lever for engagement therewith upon activation of said power means.