GB642886A - Brake - Google Patents

Abstract

642,886. Internal shoe brakes. CARNES, J. J. March 5, 1946, No. 6868. Convention date, Sept. 27, 1941. [Class 103 (i)] An internal shoe brake comprises in one form, Fig. 1, primary and secondary shoes 2 and 3 which are expanded by a hydraulic cylinder 9 and retracted by springs 18, 26 and 27, the shoe 2 being pivoted on a pin 7 secured to the backplate and the shoe 3 being focused with a recess 3a adapted to engage with an anchor pin 28 to which the springs 26 and 27 are connected. The heel 38 of the primary shoe is shaped to engage in a slot 37 in one end of an equalizing lever 82 pivoted on a pin 6 secured to the back plate, the other end of this lever being rounded for engagement with a slot in the end of the shoe 3. The brake may be applied mechanically by a linkage 30-35. In a second form, Fig. 2, a pair of levers 83, pivoted at 6 to the back plate, are coupled at one end to the lower end of the shoe 3 and at the other end to the lower ends of a pair of levers 40 mounted on a fulcrum pin 39 secured to the back plate, the upper ends of these levers being slotted to engage a pin 14 on the hydraulic plunger which applies the shoe 2. A retraction spring 17 is coupled to an anchor pin 41 co-operating with a recess in the upper end of the shoe 3. In a modification, Fig. 3, the pin 14 is connected to the mid-points of a pair of levers 42, the ends of which are slotted to engage pins 43 and 44 on the shoe 2 and levers 40 respectively. In a further modification, Fig. 4 (not shown), the levers 83 are replaced by an adjustable thrust-transmitting link, the construction being otherwise similar to that of Fig. 3 except that an additional anchor pin for the shoe 3 is arranged adjacent its lower end. Specification 526,594 is referred to. The Specification as open to inspection under Sect. 91 also describes constructions similar to that of Fig. 1 in which the upper end of the secondary shoe anchors on the plunger of the hydraulic cylinder. This subject-matter does not appear in the Specification as accepted.