US2140597A - Braking mechanism - Google Patents

Description

N. S. REYNOLDS Dec. 20, 1 938,

' BRAKING MECHANISM ori inal Filed March 1v, 1937 s I Z w F g PIC-3.5.

A TTORNEY Patented Dec. 20, 1938 "PATENT OFFICE BRAKING MECHANISM Noel S. Reynolds, St.

Louis, Mo., assignor to Joseph J. Hagen, St. Louis, Mo.

Application March 17, 1937, Serial No. 131,394

' Renewed May 31; 1938 13 Claims.

. Myv invention relates to braking mechanism, andmore particularly to improved means for adjusting the connection or jointbetween adjacent ends of two brake shoes. One of the objects of my invention is to provide an adjustable connection between adjacent ends of two brake shoes which will permit'free shifting of the connection with the shoes when they are applied to and released from the drum. 10' Another object of my invention is to provide a floating adjustable wedge means for cooperation with the guided connecting plungers between the ends of two brake shoes which will not oppose free movement of the plungers and which may be employed either as original equipment or as a replacement for other types of adjusting means now found on commercially used brake assemblies. Still another object of my invention is to provid'e an adjustable connection between two brake shoes which will permit the connection toi shift with the shoes in one direction of rotation of the drum so that the leading or primary shoe in this direction of drum rotation will apply force to the secondary shoe but which will act as an anchor means for the leading or primary shoe in the other'direction of rotation of the drum and notpermit this shoe to apply force to the other shoe.

30 Other objects of my invention will become apparent from the following description taken in connection with the accompanying drawing in which Figure 1 is a sideview of a brake assembly embodying my improved adjustable connection between one pair of adjacent ends of the shoes; Figure 21s a cross-sectional view of the connection; Figure 3 isan end view of the adjusting wedge; and Figures 4 and are cross-sectional views similar to Figure 2, showing modified con- 40 structions.

Referring to Figures 1 to 3, the braking assembly shown comprises the usual backing or dust plate I secured to a fixed part of the vehicle and enclosing the open side of the drum 2 fascam to float. -The cam is moved by the arm 8 on a rotatable shaft 9 journaled in the backing plate and the shoes are held in retracted position against the anchor post by the spring ID.

The pair of adjacent ends of the shoes opposite the actuated ends are connected together by my novel adjustable connection permitting shoe 3 to transmit force to shoe 4 when the shoes are engaged with the drum and at the same time providing means to take up the shoes for lining wear. A casing I I is secured to the backing plate between the shoe ends and provided with tubular guideways I2 vand I3 spaced on opposite sides of a bore or chamber I4. The guideway I2 has slidably mounted therein a plunger I5 which engages the end of shoe 3 and is provided with a flat inclined surface I6 on its end projecting into bore I4. Similarly, guideway I3 has slidably mounted therein a plunger H which engages the end of shoe 4 and is provided with a flat inclined surface I8 on its end projecting into bore I4. Within bore I4 is a bolt I9 and secured on its end is a flanged part 20 having a serrated surface 20' for engagement with the sides of the plungers opposite the inclined surfaces. A wedge member 2I (Figure 3) is threaded on the bolt and its flat surface 22 cooperates with inclined surface I6 and its flat surface 23 cooperates with inclined surface I8. The axis of the wedge member is eccentric to the axis of the bolt and the diameter of the wedge is less than that of bore I4 in order to permit the wedge and bolt to move with the plungers and relatively to casing II. vThe bolt I9 projects through an oversized opening 24 in casing I I to the exterior of the backing plate and is provided with a wrench receiving head 25. A closure washer 26 of a suitable material is employed to keep dust and dirt from entering opening 24, the washer being held in position by a spring 21 interposed between it and the wedge.

In the brake assembly shown, the drum normally rotates in the direction indicated by the arrow, which rotation corresponds to the forward direction of the vehicle. When the shoes are disengaged from the drum. it is desired that wedge 2I be positioned at the side of the bore toward the leading shoe 3 in order that the wedge and bolt may be free to shift with the plunger when the shoes are engaged with the drum. To insure that the wedge assumes this normal position, a relatively light spring 28 is positioned on the outer end of plunger I5 between a washer 29 and casing I I. A spring 30 of greater strength than'spring 28 is also employed between the shoes to maintain the latter in bodied in a brake assembly of the type described,

it is readily seen that when the shoes are applied to the drum and the latter is rotating in the direction indicated by the arrow, the leading shoe 3 will be able to have slight circumferential movement with the drum and by means of the connecting plungers apply pressure to shoe 4 which will anchor on post 5. The adjusting wedge and bolt freely float with the plungers and because of this, there is no binding action which will in any way resist or prevent the plungers from moving to thereby permit release of the shoes, the plungers, adjusting wedge and bolt will move freely back to their normal positions (Figure 2) under the action of spring 28.

When the shoes are applied to the drum and the direction of rotation is opposite that indicated by the arrow, shoe 3 will be forced into engagement with the drum but shoe 4 will not be able to apply force thereto through the connecting plungers as the wedge will be in engagement with casing II and because of this, it will act as an inchor for shoe 4. The brake, under these conditions, will be an ordinary two-shoe brake in which shoe 4 will act as a pivoted forward shoe and shoe 3 as a pivoted reverse shoe instead of as a two-shoe servo brake as is the case when the drum is rotating in the direction indicated by the arrow.

When it is desired to adjust the shoes to take care of lining wear, bolt 25 need only be turned in the proper direction to cause the wedge member 2! to be moved closer to the flange part 20. This moves the plungers apart and sets the shoes closer to the drum. The flat surfaces 22 and 23, during the rotation of the bolt, prevent the wedge member from rotating with the bolt and serrations 20' assist in holding the bolt in adjusted position.

In Figure 4 I have shown a slightly modified construction of the adjusting device. The casing II and plungers l5 and II are the same as previously described. Within bore I4 is positioned a cup-shaped member 3| having aligned openings 32 and 33 therein for receiving the inner ends of the plungers. The open end of member 3| has threaded therein a wedge member 34 which is provided with a frusto-conical end for cooperating with the the flat inclined surfaces of the plungers. The cup-shaped member has its axis eccentric to the axis of the wedge and normally engages the side of the casing toward the leading shoe 3 under the action of spring 28. The Wedge member 34 is provided with a tool receiving socket 3 whereby a suitable tool may be inserted through opening 24 in the casing to move the wedge relatively to the cup-shaped member 33 to 7 thereby adjust the plungers and consequently the shoes. A plug 35 is'employed to close opening 24 to prevent entry of dirt and water. The operation of the brake with this modified construction plungers I5 and H are positioned in the casing with their flat inclined surfaces reversed. The bolt 36 has secured to its inner end the frustoconical wedge member 31 which engages the flat inclined surfaces [6 and I8 of the plungers. The bolt also has threaded thereon member 38 which has its axis eccentric to that of the bolt so that one of its sides will normally engage the casing under the action of spring 28. The member 38 is provided with suitable grooves 39 for receiving the plunger and also preventing its rotation with the bolt. The conical surface of the wedge is formed withserrations 40 to assist in holding the wedge in adjusted position. When bolt 36 is turned,-the wedge will be moved toward or away from member 38, in accordance with the direction of rotation of the bolt, to provide proper adjustment ofthe shoes through the plungers. The operation of the brake with this adjustable connection embodied therein is the same as previously described.

From the foregoing description of the preferred embodiment of my invention and the modified constructions, it is apparent that I have devised an adjustable connection in which the adjusting means will not in any way resist or prevent the free movement of the plungers so that the leading shoe will apply its full force to the secondary shoe when the drum is rotating in one direction. It is also apparent that the constructions are very well adapted for replacement use on brake assemblies wherein the plungers are not permitted to float because the adjusting wedge is fixed to casing H or on braking assemblies in whichthe wedge is so mounted in casing I I that it will bind on the wall of the casing and resist free shifting of the plungers during braking or during release of the shoes.

Being aware of the possibility of modifications in the particular structure herein described without departing from the fundamental principles of my invention, I do not intend that its scope be limited except as set forth by the appended claims.

Having fully described my invention, What I claim as new and desire to secure by Letters Patent of the United States is:

1. In braking mechanism, a support, a brake drum, a pair of shoes positioned in end-to-end relation in the drum, means for expanding one pair of adjacent ends of the shoes, a stationary guide carried by the support between'the other pair of adjacent ends, shiftable plungers in the opposite ends of the guide and engaging the ends of the respective shoes, said plungers having inclined surfaces on their inner ends, a wedge engaging the inclined surfaces of the plungers, a

member engaging the sides of the plungers op posite the inclined surfaces, andmeans for moving said wedge and member relatively toward or away from each other, said wedge, member and moving means being movable as a unit with the plungers. V 7' 2. In braking mechanism, a support, a brake drum, a pair of shoes positioned in end-to-end relation in the drum, means for expanding one pair of adjacent ends of the shoes, a stationary guide carried by the support between the other pair of adjacent ends, shiftable plungers in the opposite ends of the guide and engaging the ends of the respective shoes, said plungers having inclined surfaces on their inner ends, a wedge engaging the inclined surfacesof the plungers,

a member engaging the sides of the plungers opposite the inclined surfaces, means for moving said wedge and member relatively toward or away from each other, said wedge, member and moving means being movable as a. unit with the plungers when the plungers move in one direction, and spring means for normally biasing said 75.

pair of adjacent ends of the shoes, a stationary guide carried by the'support between the other pair of adjacent ends, shiftable plungers in the opposite ends of the guide and engaging the ends 1 of the respective shoes, wedge means between the opposite ends of the guide and carried by the plungers for adjusting the distance between the plungers, said wedge means being movable with the plungers and between the ends of the guide, means carried by and shiftable with the wedge means and plungers, and adapted to operate said wedge means to effect said adjustment of the distance between the plungers, and spring means for normally biasing said wedgemeans into engagement with one end of said guide.

- 4. In braking mechanism, a support, abrake drum, a pair of shoes positioned in end-to-end relation in the drum, means for expanding one pair of adjacent ends of the shoes, a stationary guide carried by the support between the other pair of adjacent ends, shiftable plungers in the opposite'ends of the guide and engaging the ends 30 of the respective shoes, wedge means between the opposite ends of the guide and carried by the plungers for adjusting the distance between the plungers, said wedge means being movable with the plungers and between the ends of the guide,

means carried by and shiftable with the wedge means and plungers, and adapted to operate, said wedge means to efiect said adjustment of the disvided with inclined surfaces, said device comprising a threaded bolt, a shoulder carried by the end ment on the bolt, and an annular wedge member I threaded on said bolt and'of a diameter less than 1 the distance between the plunger guides, said of the bolt and restrained against axial movewedge member having its axis eccentric to the axis of the bolt and being provided with fiat beveled surfaces on opposite sides of its axis and facing the annular shoulder for cooperation with the inclined surfaces of the plungers, said beveled surfaces lying in planes having the same angular relation to the axis of the bolt.

6.An adjustingdevice for cooperation with a pair of brake shoe connecting plungers mounted in spaced guides and having adjacent ends provided with inclined surfaces, said device comprising a threaded bolt, a frusto-conical member secured against axial movement to the end of the bolt and having its axis coinciding with the axis of the bolt and its base positioned at the end of the bolt, and an annular member threaded on i saidbolt and of a diameter'less than the distance between the plunger guides, said annularmemher having its axis eccentric to the axis of the a bolt. 7

7. An adjusting device for cooperation with a pair of brake shoe connecting plungers mounted in spaced guides andhaving adjacent ends provided with inclined surfaces, said device comprising a threaded bolt, a frusto-conical member secured to the end of the bolt and having its axis coinciding with the axis of the bolt and its base positioned'at the end of the bolt, and an annular member threaded on said bolt and of a diameter less than the distance between the plunger guides, said annular member having its axis eccentric to the axis of the bolt and the surface thereof facing the frusto-conical member being providedwith two opposed radially extending grooves for receiving the ends of the plungers.

8. 'An adjusting device for cooperation with a pair of brake shoe connecting plungers having adjacent ends provided with inclined surfaces, said device comprising a cup-shaped member provided with threads on its inner wall and having openings in opposed sides thereof for receiving the ends of the plungers, and a member threaded in the cup-shaped member and provided with a conical surface on its inner end.

9. An adjusting device for cooperation with a pair of brake shoe connecting plungers having adjacent ends provided with inclined surfaces, said device comprising a cup-shaped 'member having its internal wall eccentric with respect to the external wall, said internal wall being provided with threads and opposed sides of said cup-shaped member having openings for receiving the ends of the plungers, a member threaded in the cup-shaped member and provided with a conical surface on its inner end, and tool receiving means at its outer end.

10. In braking mechanism, a combined adjustable connecting device and anchor for a brake assembly having a pair of brake shoes and comprising a fixed casing provided with spaced guides, slidable plungers in said guides, a wedge engaging the plungers, a member cooperating with the plungers on the sides opposite those engaged by the wedge, and threaded means for relatively moving the wedge and member axially toward or away from each other, said member having its axis eccentric to the axis of the threaded means and normally adapted to engage one of said spaced guides.

11. In braking mechanism, a combined adjustable connecting device and anchor for a brake assembly having a pair of brake shoes and comprising a fixed casing provided with spaced guides, slidable plungers in said guides, a wedge engaging the plungers, a member cooperating with the plungers on the sides opposite those engaged by the wedge, and a threaded bolt extending to the exterior of the guide for relatively moving the wedge and member toward or away from each other, said wedge being provided with means preventing its rotation with the bolt and with an eccentric part adapted to normally engage one of said guides and said wedge, member and bolt adapted to be movable with the plungers as a unit.

12. An adjusting device for cooperation with a pair of brake shoe connecting plungers having adjacent ends provided with inclined surfaces, said device comprising a wedge for engaging the inclined surfaces of the plungers, a member engaging the sides of the plungers opposite the inclined surfaces and having a threaded opening, and means for moving said wedge and member relatively toward and away from each other and comprising a threaded portion carried by said wedge for cooperating with the threaded opening in the member and means for rotating the wedge and threaded portion.

13. An adjusting device for cooperation with a pair of brake shoe connecting plungers having adjacent ends provided with inclined surfaces, said device comprising a cup-shaped member provided With-threads on its inner wall and having openings in opposed sides thereof for receiving the ends of the plungers, a wedge member for cooperating with the inclined surfaces of the plungers, and means for moving the wedge member relative to the cup-shaped member and comprising means associated with the wedge member and the threads of the cup-shaped member.

NOEL S. REYNOLDS.

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