GB503485A - Improvements in or relating to vehicle brakes - Google Patents

Abstract

503,485. Testing brakes ; electric signalling systems. GALLE, J. B. P. H. Oct. 4, 1937, No. 26846. Convention date, Oct. 8, 1936. [Class 103 (i)] [Also in Group XXXVIII] Means for comparing the braking action of the brakes of a vehicle comprises a thermometric resistance or a thermo-electric cell associated with each brake and so connected in a circuit in pairs or otherwise with a galvanometer that when the temperatures of the brakes and thus the braking actions thereof are the same the galvanometer is not deflected. Thermo-electric couples 1, 2, 3, 4, Fig. 1, associated each with one of the four brakes of a vehicle may be connected in opposition in pairs as shown, the pairs 1, 2 and 3, 4 being connected in turn to the galvanometer B by a switch. The switching arrangements may also be such as to allow of connecting the pairs 1, 3 and 2, 4 to the galvanometer. When thermometric resistances 1, 2, 3, 4, Fig. 3, are used instead of thermo-electric cells, these may be arranged as a Wheatstone's Bridge as shown. As long as the temperature of the brakes and thus the resistances remain equal the galvanometer is not deflected. To determine which brake is out of adjustment when the galvanometer is deflected, the resistances may be disconnected in pairs and invariable resistances R1, R2 be substituted in the corresponding branches by switches Dl, D2. In the case of the six brakes of a six-wheeled vehicle, branches 3, 4, for instance, may each include the resistances of two brakes. The thermometric elements may be arranged on a brake shoe or within the drum and with the remainder of the testing apparatus may be removable for use in garages &c. According to the Specification as open to inspection, under Sect. 91, thermometric resistances may be arranged to be connected separately in turn to a galvanometer or a pair may be connected to the two windings of a differential galvanometer. Further, four thermo-electric cells may be connected in series or in opposition in the branches of a bridge in the diagonal of which a galvanometer is connected. Thermometers operating by expansion of solids and liquids and connected to indicators by hydraulic or mechanical means may also be used. The arrangement of a pair of steam-pressure thermometers acting differentially on a pointer through distortable metal manometric tubes is also described. This subject-matter does not appear in the Specification as accepted.