Patent GB-1489192-A (GB)
Title: Brake assembly for a bicycle
IPC: F16C1/22
Filed: 1974-10-03
Abstract: 1489192 Bicycle brake systems; automatic adjustment; Bowden mechanisms SHIMANO INDUSTRIAL CO Ltd 3 Oct 1974 [4 Oct 1973 13 Feb 1974 4 April 1974] 42942/74 Headings F2E and F2K A bicycle brake system whereof the brake is actuated by movement of an inner wire b relative to an outer sheath a of a Bowden cable is adjustable automatically and comprises an adjusting member 10, 12 mounted on a first supporting member 7 and an actuating member 14 mounted on a second supporting member 8; the adjusting member 10, 12 has associated therewith a clutch spring 13 having a straight end 13a which passes through a helical slot 14a in the member 14 and is movable within the width of the slot 14a with a range of movement equivalent to the desired brake clearance-when this movement has been taken up during a braking action the end 13a is rotated along the slot 14a and this causes adjusting movement of member 10, 12 to shift the position of the outer sheath a relative to the wire b to thereby compensate for brake component wear or for elongation of the wire b. The assembly of Fig. 2 is utilized in the brake systems illustrated by Figs. 6-8, 9-10, 11- 12; it has a retaining section 10 for one end of sheath 10a, and an adjusting section 12, which may be formed integrally with the retaining section 10, and which is screw-threadedly connected to the first supporting member and is rotatable during adjusting movement to shift the section 10 along its axis. The actuating member 14 is formed with a cylindrical end surrounding the section 10 and having the slot 14a cut therein, and the member 14 is provided with a notch 14b which serves to fix the member 14 to the second supporting member. If during a braking action the end 13a is caused to be rotated the spring 13 is rotatedduring brake application the clutch spring 13 is rotated in one direction (X, see Fig. 5) in which the spring 13 is displaced relative to the adjusting section 12, but during brake release the spring 13 rotates in the reverse direction (Y, see Fig. 4) in which it tightens around the adjusting section 12 and rotates section 12 to shift section 10 linearly. In the side-pull caliper brake system illusstrated in Figs. 6-8 brake arms 1, 2 bearing pads 3, 4 are connected by means of a bolt 5. A supporting arm 6 integral with arm 1 provides the member 7 screw threadedly connected to adjusting section 12, and the arm 2 provides the member 8 affixed to member 14 and wire b by means of a bolt (20). Wear of pads 3, 4 or elongations of wire b causes adjustment as described with reference to Fig. 2. In the centre-pull caliper brake system shown in Figs. 9, 10 the ends of arms 33, 34 are attached to a single wire 39 supported by a detent 40 forming the second supporting member which detent also retains inner wire b. An arm 41 holds wire b under tension, and an aperture 41a in arm 41 slidably mounts a support 43 forming the first supporting member. On member 43 is pivotally mounted a cam plate 45 having an operating lever 44 for a quickrelease mechanism. A fixed pin 46 in contact with cam plate 45 fixes the supporting member 43 in one position after movement thereof and also prevents cam plate 45 from rotating. Figs. 11-12 illustrate a disc brake system having a bracket member 51 provided with a brake body 52 of U-section to receive a disc D. The body 52 is formed of two separated blocks connected by a bolt 53-one block has a first pad screwably fixed thereto by means of a bolt, while the second block is provided with a ball, a cam and a movable pad. The movable pad is screwed to a shaft 55 of a brake arm 54 by a bolt, whereby rotation of arm 54 causes the movable pad to be pressed into contact with disc D. In this embodiment, the first supporting member 56 is fixed to the bracket member 51 and the brake arm 54 serves as the second supporting member. In the form of assembly illustrated in Fig. 3 (not shown) a rotatable section (16) is screwably engaged with a section 12 which is prevented from rotating by co-operation with the first supporting member. A clutch spring (13) is wound around the section (16) and during adjustment the section (16) is rotated to move the section (12) linearly.