GB386672A - Improvements in band brakes - Google Patents

Abstract

386,672. Internal - expanding bandbrakes. FROMAGET, P. M., MontÚe Queyvas, Toulon, Var, France. July 14, 1931, No. 20242. Convention date, July 16, 1930. [Class 103 (i).] In an internal expanding self-energizing band-brake of the type in which one end of the band is adapted to abut a stop 8 situated between the ends of the band and in which floating levers 2, 2<1> act on these ends, the axes 2a, 2a<1> of the levers are so located relatively to the brake band ends and to each other and the lengths of the levers are so chosen that when the brake is applied the band ends are moved in an arc of a circle such that the angle at which the extremities of the friction lining are applied to the drum is a small angle which is maintained substantially constant. An example of such a brake including dimensions is described. The bell-crank levers 2, 21 are pivotally mounted on levers 3, 3<1> pivoted at 13 to a member 9 fixed to the cover-plate of the brake-drum, the overlapping inner ends of the levers 2, 2<1> being acted on by the flat or concave end of an operating-lever 6, or by a cam, or by a rack-and-pinion device, actuated manually, or by a flexible membrane, or by an air or hydraulic piston, to force the ends of the band into contact with the drum. In the inoperative position the band closes on the stop 8 by its own resiliency and with the aid of a spring 14. The band is guided and supported at intermediate points by bolts 21 carried by fixed angle-plates 22 engaging slots in the band. The heels 5, 5<1>, Fig. 1, of the levers 2, 2<1> may be on the same level or, to compensate for the heels being at unequal distances, as shown, from the pivot 61, the levers 2, 2<1> may be of different lengths. In the case of brakes of small diameter, e.g. motorcycle brakes, the pivots 13 may be on the opposite side of the wheel hub to the position shown in Fig. 2 and the levers 3, 3<1> arched to clear the hub. A cooling-device for the brake comprises ribs 25, Fig. 8, welded on the brakedrum and holes 27 in the drum through which cooling air passes to escape by the opening 28 between the cover-plate and the drum. Openings in the band may be provided to allow the passage of a greater quantity of air between the band and the drum.