US2065292A - Braking apparatus - Google Patents

Description

Deg. 22, 1936.

s. SCHN ELL 2,065,292

BRAKING APPARATUS Filed NOV. 17, 1933 3 Sheets-Sheet l 2 Inventor SCHNELL STE Att'y.

BRAKING APPARATUS Filed Nov. 17, 1933 3 Sheets-Sheet 2 Inventor 5T EV SCHNELL glwm Att'y.

22, 1936. s. SCHNELL 2,065,292

BRAKING APPARATUS Filed Nov. 17, 1935 Sheets-Sheet 3 I FlG.8. 22

Inventor STEVE SCHNELL Patented Dec. 22, 1936 UNITED STATES PATENT -OFFlCE BRAKING APPARATUS Steve Schnell, Overland, M0,, assignor to Wagner Electric Corporation, St. Louis, Mo., a corporation of Delaware Application November 17, 1933, Serial No. 698,406

20 Claims.

. the distribution of pressure between it and the drum when the band is applied to the drum.

A more specific object of my invention is to provide the rear section of a substantially 360 degree hand brake with a circumferentially extending member restrained from radial movement at its inner end and with means for applying a radial pressure to the member when the band is applied to the drum.

Other objects of my invention will become apparent from the following description thereof taken in connection with the accompanying drawings in which Figure 1 is a side elevation of a brake assembly (the drum being shown-in section) showing my invention embodied therein; Figures 2, 3 and 4 are cross sectional views on the lines 2---2, 33 and 4-4, respectively, of Figure 1; Figure 5 is a side elevation, partly in section, of a modification of the brake assembly shown in Figure .1; Figures 6 and 7 are cross In accordance with my invention I provide the rear section of the band with an arcuate member 5 extending from the central portion of the band to the rear end thereof. The inner end of the arcuate member is provided with an arcuate slot 6 through which extends a pivot pin I, the arc of each side of the slot having its center coinciding with the center of the drum. The pivot pin 1 is eccentric to the portion of the pin mounted in the backing plate to thus provide adjustability of the end of the member, and the pin is provided with a washer 8 for preventing lateral shifting of the end of the arcuate member.

The arcuate member 5, rearwardly of the pivot l, is secured to the band 3, the securing means comprising a key 9 on the arcuate member extending into a slot ID in the band and welded thereto, as shown. The arcuate member is in contact with the band over the portion of the hand between this point and the rear end of the band, and free from the band between this point and the pivot l. The outer or rear end of the arcuate member is not secured to the band but is provided with a key ll cooperating with an elongated slot l 2 in the band for preventing relative lateral movement of the arcuate member and the band.

A combined anchor and radial pressure apply- 7 ing device l3 cooperates with the arcuate member at a point between the point where the arcsectional views on the lines 6-6 and 'l--'|, re-/ ;uate member is secured to the band and the spectively, of Figure 5; Figure 8 is a side elevarear end of the arcuate member, thus providing tion," partly in section, 'of still another modified brake assembly; and Figures 9, 10 and 11 are cross sectional views on the lines" 9-41, l0I0 and "-4 I, respectively, of Figure 8.

Referring to Figures 1 toe! of the drawings, the numeral 1 indicates the usual brake-drum secured to a wheel of a vehicle, the open side of which is provided with a support or backing plate secured to a fixed part of-the vehicle. Situated within the drum is a substantially 360 degree flexible brake band 3 provided witha friction lining 4. This band, when expanded into engagement with the drum, (assuming the drum to be rotating in the direction of the arrow) will not produce a substantially uniform pressure between the band and the drum over the surface of contact due to the flexibility of the band'and the wrapping eifect. This nonuniform pressure is mostly over the rear" section of the band and results in greater wear 'of the lining over this section of the band than over the other sections and also'produces undesirable squeaks or squeals. a

nYeans for anchoring the band and applying raflanged ends. A U-shaped abutment member I6 is secured to the backing plate 2 by suitable means, such as rivets, and presents a pair of abutment surfaces l1 and 18, one on each side of the arcuate member. The opening I! in the arcuate member is also provided with an abutment surface l9 parallel with the abutment sur faces I! and Hi. All of these abutment surfaces" are at an angle to a radial line of the The flanged ends of the roller l5 cooperate with, the fixed abutment surfaces I1 and hand the waist of the roller cooperates with the abutment In order to provide an anchor for the-band when it is applied to the drumand the I rotating in a reverse direction, the backing plate has mounted therein an adj table anchor pin 20 cooperating with the inner end of the arcuate member. The anchor pin 20 is so adjusted that in the off" position of the band the abutment surfaces l1, l8 and ill will engage the roller and the inner 'end of the arcuate member will engage the anchor pin 20.

The forward end of the band is provided with a reinforcing member 2|, keyed and welded to the band as shown. A suitable expanding means, as for example, a hydraulic motor 22, is adapted to engage and expand the forward end of the band and the rear end of the arcuate member to thereby apply the band. A return spring 23, secured to the forward end of the band, and the 4 arcuate member biases the band to off position, the "off position clearance of the band being determined by the usual adjustable stops 24 and 25.

In operation of my improved brake, when the band is applied to the drum by the actuating means, (assuming the drum to be rotating in the direction of the arrow-the forward direction of the vehicle) the band will anchor at the device l3. Circumferential movement of the band with the drum will cause the roller l5 to roll on .the abutment surfaces ll, l8 and I9 and impress a radial pressure through the arcuate member and on the band. The amount of radial force produced by the device can be varied by varying the angle of inclination of the surfaces.

30 If the inner end of the arcuate member were not pivoted at I, the arcuate member would have a tendency to rotate in a clockwise direction about the roller I5, thus causing a greater pressure between the band and the drum forwardly of the roller and a lesser pressure rearwardly of, the roller. The pressure forwardly of the roller would also be increased as a result of the "wrapping effect of the band. However, with the inner end of the arcuate member piv- 4 oted on the pin 1, such end is unable to move radially toward the drum. As a result of this, the high pressure between the band and the drum, which would develop if the end of the arcuate member were not restrained from radial 45 movement toward the drum, is prevented and the arcuate member is rotated about the pivot 1 by the radial pressure device l3, thus causing the arcuate member to "apply a greater pressure to the band rearwardly of the roller. The rear :50 section of the-band thus engages the drum with a substantially uniform pressure. By adjustment of the pin I the pressure between the band and drum forwardly and rearwardly of the roller, can be varied as desired. The adjustable 55 pin 1 and the adjustable stops 24 and 25 provide means to take up the wear of the brake lining. It is thus seen that by my novel brake the rear section of the band is made to engage the drum with a substantially uniform pres- 60 sure, which pressure will be substantially the same as the pressure between the forward section of the band and the drum which is approximately uniform in a flexible band of the type shown, thus producing a band brake that 65 has a uniform pressure between the band and the drum over the entire friction contacting surface.

When the drum is rotating in the direction opposite the arrow, the band will be anchored 70 at the pin 20 and the roller device l3 will not function. In this direction of rotation (rearward movement of the vehicle) no great braking pressure is necessary to hold the vehicle and, therefore, the band need not engage the drum 75 with a substantially uniform pressure as is necessary in the forward direction of the vehicle. However, if such a uniform pressure were desirable, it is clearly within the scope 01 my invention to duplicate the arcuate member and cooperating structure on the forward" section of the band.

Referring to the modification shown in Figures 5, 6 and '1, the adjustable stop 24 is eliminated and the combined anchor and radial pressure device l3 moved to a point closer to the end of the arcuate member 5 which is attached to the band and mounted on the pin 1 in the same manner as in Figure 1. The combined anchor and radial pressure applying device comprises an inclined surface H on the abutment member l6 secured to the backing plate 2, a parallel inclined surface IS on the arcuate member, and a roller l5 interposed between the parallel surfaces.

The forward section of the band 3 has secured thereto a reinforcing web 26 extending to approximately the center of the band, the securing means being in the form of spaced keys welded in slots in the band, although other means may be used. The inner end of the web is free from the band,,as shown, and provided with an arcuate slot 21 for receiving the eccentric portion 28 of an adjustable pin 29 mounted in the backing plate.

The operation of this brake is very similar to that shown in Figure 1. The positioning of the combined anchor and radial pressure applying devixe nearer the outer end of the arcuate member 5, however, results in greater radial pressure between the band and the drum at a point adjacent the rear end of the -band when it is applied to the drum. The increased pressure at this point decreases the tendency of the band to chatter and squeak. Also, because of the position of the combined anchor and radial pressure applying device, the adjustable stop 24 of the assembly of Figure 1.may be eliminated. Adjustment to compensate for wear of the lining on the rear section of the -band is accomplished by adjusting the reverse anchor pin 20, the band being forced outwardly by the relative movement of the inclined surface H on the roller l5.

By providing the forward section of the band with reinforcing web 26, any tendency of this section to buckle under overloading of the brake, as may occur on truck and bus brakes, is eliminated. The adjustable pin 29 also permits the pressure between the forward section of the band and the drum to be controlled as desired when the brake is applied and thereby prevent excessive pressures being built up adjacent the central part of the band.

In the modified brake assembly shown in Figures 8 to 11 the pins 1 and 74 and the anchor 20 of the brake assembly shown in Figure 5, have been replaced by a single adjustable means. The construction of the combined anchor and radial pressure applying device is also slightly different than that embodied in the other brake assemblies shown.

The drum l, backing plate 2, and brake band 3 are the same as previously described. The rear section of the band is provided with a U- sha-ped arcuate member 3|, the side flanges 32 of which are spaced apart, as shown. This arcuate member is secured to the band at suitable points by welds. The combined anchor and radial pressure applying device I3" for the rear section of the band is mounted upon an adjustable pin 33 clamped to the backing plate 2, this pin being provided with an eccentric portion 34 upon which is carried an L-shaped arm 35 held in position by a key 34'. The lowerend of the arm 35 extends into the space between the flanges 32 of the arcuate member 3| and is provided with a slot 36 whichreceives a pin 31 mounted in the flanges. The upper end of the arm adjacent pin 33 is provided with a laterallyj extending portion 38, also entering the space between the flanges 32. The arcuate member 3| has riveted thereto an abutment 39 lying between the flanges 32, said member also being provided with a key extending through the base of the member 3| and the band, as shown. A floating roller 40 is interposed between the abutment 39 and the portion 38 of the arm 35.

The forward section of the band 3 has secured thereto, by suitable keys and welds, a reinforcing web 4|, the inner end of which extends between the flanges 32 of the inner end of the arcuatemember 3|. The over-lapping ends of 'the member 3| and the web 4| are, respectively,

provided with registering arcuate slots 42' and 43 \for the reception of an eccentric pin 44 clamped to the backing plate 2 by an integral flange 45 and a nut 46. 1A washer 41 on the inner end of the pin 44 holds the member 3| and the web 4| in position. The slots42 in the end of the member 3| are so positioned that the member 3| abuts the pin 44 to form an anchor for the band when the drum is rotating in, a direction opposite the arrow. The slot 43 in the end of the web is so positioned that the web may have slight circumferential movement in welded thereto a member 48 forming an engaging surface for the brake expanding hydraulic motor 22. The retractile spring 23 biases the band to "off position, such position being determined by the adjustment of the combined anchor and radial pressure applying device l3".

In operation of the brake, therear section of .the bandis applied to the drum in the same manner as the rear section of the band in the brake assembly shown in Figure 1, the comthe same operation as the-similar devices shown in Figures 1 and 5, the construction, however, being varied only for proper cooperation with the U-shaped arcuate member 3| and for facilitatingassembly and disassembly. The single pin 44 prevents the inner end of the member 3| and the inner end of the web 4| from having outward radial movement when the band is ap-- plied, thus controlling the braking pressure of the band in the same way as is done in the brake assembly of Figure 5. When the drum is rotating in a reverse direction, the band anchors on the pin 44.

The band is properly adjusted by'the adjust-. ment of the pin 44 and the pin 34, the pin and slot connection .of the arm 35 with the U-shaped arcuate member 3| permitting the arm 35 to be moved relative to the member 3| during adjust- -ment of the pin 34.

Having fully described my invention, what I Patent of the United States is:

'claim' as new and desire to secure'by Letters 1. In braking apparatus, the combination of band for cooperation with the drum, a support, a pressure modifying element secured to the band, one end of saidelement being free from the band and said free end being mounted on the support by means permitting circumferential mo ment of the free end of the element and the b nd but maintaining said free end at a fixed dist nce from the drum, and anchoring means for e band.

2. In braking apparatus, the combination of a brake drum, a substantially 360 degree brake band adapted to be expanded into engagement with the drum, a support for the band, a pressure modifying element secured to the band at a point intermediate the ends of the element, one end of the element being free from the band and said free end being mounted on the support by means permitting circumferential movement of the free end of the element and the band but maintaining said free end at a fixed distance from the drum, and anchoring means for the band.

3. In braking apparatus, the combination of a support, a brake drum, a substantially 360 degree brake band adapted to be expanded into engagement with the drum, 9, pressure modifying member secured to the band, means on the support for preventing outward radial movement of a portion of said member but permitting circumferential movement thereof, said member being secured to the band at a point circumferentially spaced from said last named means and free from the band opposite'said means, and means for anchoring the band. a

4. In braking apparatus, the combination of a support, a brake drum, a substantially 360 egree brake band adapted to be expanded into engagement with the drum, a. pressure modifying memberextending over a substantial portion of the band and secured thereto, means on the support adjacent the band for preventing out- *ward radial movement ,of a portion of said member but permitting circumferential move- -ment thereof, the point of securement of said member to the band being 'circumfere'ntially spaced from said last named means, and means for anchoring the band.

5. In braking apparatus, the combination of a. support, a brake drum, a substantially 360 degree brake band adapted to be expanded into engagement with the drum, means for anchor ing the band, means for restraining a portion of the band from free outward radial movement toward the'drum and for applying a pressure to another portion of the band, said means comfrom the support mounting.

6. In braking apparatus, the combination of a support, a brake drum, a substantially 360 degree brake band adapted to be expanded into engagement with the drum, an arcuate member extending over and contacting a substantial portion of the rear portion of the band, means at the inner end of said member for preventing outward radial movement thereof but permitting circumferential movement, means for securing the arcuate member to the band at a point oircumferentially spaced from its inner end, and means foranchoring the band.

'7. In braking apparatus, the combination of a support, a brake drum, a brake band adapted to have its ends expanded into engagement with the drum, an arcuate member extending over a substantial portion of the band and restrained against outward radial movement adjacent one of its ends, said end beingfrec from the band and an intermediate portion of said arcuate member being secured to the band, and anchoring means for the band.

8. In braking apparatus, the combination of a support, a brake drum, a brake band adapted to have its ends expanded into engagement with the drum, and means for restraining free outward radial movement of a part of the rear portion of the band when the band is applied to the drum, said means comprising a circumferentially movable member pivoted on the support and secured to the band at a point circumferentially removed from the pivot but free from the band adjacent the pivot.

9. In braking apparatus, the combination of a support, a brake drum, a brake band adapted to have its ends expanded into engagement with the drum, and means for restraining free outward radial movement of a part of the rear portion of the band and for applying a pressure to another part of said rear portion when the band' is applied to the drum, said means comprising a circumferentially movable arcuate member pivoted on the support and secured to the band at a point circumferentialiy removed from the pivot but free from the band adjacent the pivot.

10. In braking apparatus, the combination of a support, a brake drum, a brake band adapted to have its ends expanded into engagement with the, drum, a circumferentially extending member secured to the band and pivoted on the support against free outward radial movement, and means for anchoring the band and applying a radial pressure to the member.

11. In braking apparatus, the combination of a support, a brake drum, a brake band adapted to have its, ends expanded into engagement with the drum, a circumferentially movable arcuate member having a portion mounted on the support against free outward radial movement and secured to and contacting the rear section of the band, and means for anchoring the band and applying a radial pressure to the band through said member when the band is applied to the drum,

12. In braking apparatus, the combination of a support, a brake drum, a brake band adapted to have its ends expanded into engagement with the drum, a clrcumferentially extending member in contact with the band and mounted on the support against outward radial movement and connected to an intermediate portion of the band, means for anchoring the band and applying a radial pressure to the member when the band is applied to the drum in the forward direc tion of the vehicle, and means for anchoring the band when it is .applied to the drum in the reverse direction.

13. In braking apparatus, the combination of 0. support, a brake drum, a brake band adapted to embrace the major portion of the drum friction surface, a circumferentially extending member secured to the band and contacting the major portion of the rear section of the band and mounted on the support against outward radial movement .but free to move circumferentially, means for anchoring the band and applying a radial pressure to the arcuate member,

and expanding means enaaa fl one end of the band and the other end of the arcuate member.

14. In braking apparatus, the combination of a support, a brake drum, a brake band adapted to have its ends expanded into engagement with the drum, an arcuate member mounted at one end on the support by means permitting circumferential movement but preventing outward radial movement and, secured to the band at an intermediate point and contacting the band over a substantial portion, a combined anchor and radial pressure applying device acting on the arcuate member when the device is rotating in one direction and the band is applied, and a stop engaged by said member in the other direction of rotation of the drum.

15. In braking apparatus, the combination of a support, a brake drum, a brake band adapted to have its ends expanded into engagement with I the drum, an arcuate member secured to the band and mounted at one end on the support by means permitting circumferential movement but preventing outward radial movement, a portion of said arcuate member contacting a substantial portion of the band and the remaining portion adjacent the support mounting being free of the band, and means for anchoring the arcuate member and applying a radial pressure thereto. a

16. In braking apparatus, the combination of a support, a brake drum, a brake band adapted a support, a brake drum, a brake band adapted to be expanded into engagement with the drum, a pair of arcuate members secured to the band, means on the support cooperating with the adjacent ends of the arcuate members for preventing outward radial movement of the inner ends but permitting circumferential movement thereof, the arcuate members being free of the band adjacent said last named means, and means for anchoring the band. a

18. In braking apparatus, the combination of a support, abrake drum, a brake band adapted to be expanded into engagement with the drum, a pair of arcuate members secured to the band and each extending over a substantial-arc there- 01, means cooperating with the adjacent ends of the arcuate members which are remote from the ends of the band for preventing outward radial movement of the inner ends but permitting circumferential movement thereof, and means for anchoring the band.

19. In braking apparatus, the combination of a support, a brake drum, a brake band adapted to be expanded into engagement with the drum, 2. pair of arcuate members secured to the band, one extending over the forward section of the band and the other over the rearward section of the band, means cooperating with the inner ends of the arcuate members for preventing outward radial movement of the inner ends but permitting circumferential movement thereof, means for applying an outward radial pressure on the rear section of the band, and means for anchoring the band.

20. In braking apparatus, the combination with a support, a brake drum, a substantially 360 degree brake band adapted to be expanded into engagement with the drum, a pair of armate members secured to the band, one extending 10 over the forward section of the band and the other extending over the rear section and the inner ends thereof being free from contact with the band, means preventing outward radial movement of the inner ends of the arcuate members, means for anchoring the band and applying a radial pressure to the rear section thereof when the drum is rotating in a forward direction, and means for anchoring the band when the drum is rotating in a reverse direction.

STEVE SCI-NEIL.

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