Brake shoe assembly including brake shoe spring

#The present invention relates to an assembly of a brake shoe with an associated brake shoe spring.

#There are already known brake shoe assemblies in which the brake shoe includes a carrier plate and a lining of friction material secured to the carrier plate, and in which the brake-shoe spring has two legs that merge with and are interconnected by a loop-shaped portion which is received in a recess of the carrier plate and is secured in the recess normal to the plane of the carrier plate.

#Furthermore, a brake shoe assembly is known from the German published patent application No. 29 37 149, wherein the brake shoe spring is constructed as a wire spring and its loop-shaped portion is retained in the recess of the carrier plate against movement radially and simultaneously in the circumferential direction of the brake shoe. While there is also a limited axial securing in position of the brake-shoe spring in the direction normal to the opening of the recess prior to the mounting of the brake-shoe spring on a brake caliper, due to the frictional engagement between the brake-shoe spring and the carrier plate since the loop-shaped portion is clamped in the recess of the carrier plate with radial preload, this frictional engagement is discontinued after the mounting of the brake shoe assembly on a brake caliper owing to the decrease in the outer diameter of the loop-shaped portion resulting from the loading of the brake-shoe spring. The clearance between the brake-shoe spring and the recess which results from this diameter reduction is conducive to slipping of the spring out of the recess. This situation is further aggravated by the effect of vibrations on the brake during the operation of the vehicle equipped with such a brake in that such vibrations can actually cause the loop-shaped portion of the spring to slip out of the recess. However, other forces acting on the brake, the brake shoes or the spring, may have the same effect. Of course, this is very disadvantageous since the disassociation of the spring from the brake shoe may result in a loss of the spring and will certainly impair the operation of the brake, if not render the same inoperative.

#Above-mentioned and other features and objects of this invention will become more apparent by reference to the following description taken in conjunction with the accompanying drawing, in which:

#FIG. 1 is a front elevational view of the brake shoe assembly of the present invention, showing the major surface of the carrier plate to which no friction material is secured;

#FIG. 2 is a top plan view of the brake shoe assembly FIG. 1;

#Referring now to the drawing in detail, and first to FIGS. 1 and 2, it may be seen that they show a brake shoe assembly which comprises a carrier plate 1, a lining 2 of friction material secured to the carrier plate 1, and a brake-shoe spring 3.

#As shown in FIGS. 1 through 4 and 8, the brake-shoe spring 3 is supported in a recess 5 in the carrier plate 1. The recess 5 opens onto an edge surface 4 of the carrier plate 1. A projection 7 extends into the open recess 5 along the plane of the carrier plate 1 which includes a circumferential direction 6 of the brake shoe assembly as considered in the position assumed by the latter relative to the brake. The projection 7 bounds an opening 8 extending substantially concentrically relative to the open recess 5. The brake-shoe spring 3 comprises a loop-shaped portion 9 which is composed of two circular convolutions 10 and 11 extending in parallel to one another. The convolutions 10 and 11 embrace the projection 7 at the respective two sides of the carrier plate 1 and abut respective end faces 12 and 13 of the projection 7.

#As illustrated in FIGS. 1 through 4, the respective radially outer edges of the convolutions 10 and 11, which are situated below a center line 14, abut on the two respective sides of the projection 7 on respective facing lateral surfaces 15 and 16 that bound the open recess 5. This provides for the brake-shoe spring 3 to be held stationary on the carrier plate 1 in the radially downward direction as considered in the drawing, and also in the circumferential direction 6. The projection 7 provides for positive engagement of the brake-shoe spring 3 with the carrier plate 1 in direction normal to the plane of the carrier plate 1. This is accomplished by the penetration of the projection 7 between the two convolutions 10 and 11. At the major surface of the carrier plate 1 to which no friction material is affixed, there are provided, adjacent a portion of the lateral surface 15 which has an annular segment configuration, lateral surfaces 17 and 18 which extend substantially tangentially of the convolution 10 and which are inclined at an acute angle to the center line 14 while extending substantially parallel to one another. At the other major surface of the carrier plate 1 to which the friction material lining 2 is affixed (compare FIGS. 2 and 5), there are arranged, adjacent a circular portion of the lateral surface 16, lateral surfaces 19 and 20 which extend tangentially of the convolution 11 and at a right angle relative to the center line 14 radially outwardly, while extending substantially parallel to each other.