Abstract: Wear of a rubbing member of a triction couple, such as an iron brake disc (15), which is subject to slow wear by frictional engagement by brake pads (17), is determined by attaching a carrier member (25) of wear determining arrangement (24) to the rubbing surface of the disc by electromagnet (28) and causing a transducer (33), such as magnetic displacement sensor having probe (33/2), to s an across the surface along a track (48). After an initial scan to map the surface the carrier is removed and re-attached after a period of brake usage, whereupon the surface is scanned again and wear assessed. The carrier is provided with feet (26/1) and biassed by a resilient electromagnet mount against the surface.

Abstract: A magnetic clamping arrangement (10) for holding the arrangement, and in particular a body (5), operably clamped with respect to a ferromagnetic surface (6) by way of a body datum face (8), comprises housing (12) mounted on the body, and electromagnet (16) carried by the housing. The electromagnet comprises a core (18), having three limbs 20.1, 20.2 and 20.3, each terminating in a pole face 22.1, 22.2 and 22.3, being formed by a plurality of ferromagnetic transformer laminations (26). stacked together and slideable with respect to each other in a direction to and from the pole faces. Lamination bias (36), in the form of masses 38, 40.1 and 40.2 of resilient compressible material, defined quiescent pole faces from which individual laminations may depart by sliding when forced against a surface having ridges and/or grooves extending in the lamination planes, but exerts a restoring force on such laminations so displaced.

Abstract: Wear of a rubbing member of a triction couple, such as an iron brake disc (15), which is subject to slow wear by frictional engagement by brake pads (17), is determined by attaching a carrier member (25) of wear determining arrangement (24) to the rubbing surface of the disc by electromagnet (28) and causing a transducer (33), such as magnetic displacement sensor having probe (33/2), to s an across the surface along a track (48). After an initial scan to map the surface the carrier is removed and re-attached after a period of brake usage, whereupon the surface is scanned again and wear assessed. The carrier is provided with feet (26/1) and biassed by a resilient electromagnet mount against the surface.

Abstract: A magnetic clamping arrangement (10) for holding the arrangement, and in particular a body (5), operably clamped with respect to a ferromagnetic surface (6) by way of a body datum face (8), comprises housing means (12) mounted on the body, and electromagnet (16) carried by the housing means. The electromagnet comprises a core (18), having three limbs 20.1, 20.2 and 20.3, each terminating in a pole face 22.1, 22.2 and 22.3, being formed by a plurality of ferromagnetic transformer laminations (26). stacked together and slideable with respect to each other in a direction to and from the pole faces. Lamination bias means (36), in the form of masses 38, 40.1 and 40.2 of resilient compressible material, delined quiescent pole faces from which individual laminations may depart by sliding when forced against a surface having ridges and/or grooves extending in the lamination planes, but exerts a restoring force on such laminations so displaced.

Abstract: Apparatus 10 (FIG. 1), for testing samples of friction material 31, 32 in rubbing contact with a surface 33 of a rubbing element 34, comprises a table 12 for supporting the rubbing element and a load cell 16 for sensing the load imposed by the frictionally coupled rotating samples from which the coefficient of friction can be determined. To make the tests repeatable rapidly and with identical starting conditions cooling means 40 is interposed between the rubbing element and table. Cooling means 40 comprises a fluid cooled heat exchanger 41, conveniently cooled by local main supply water supplied at its natural temperature, and thermoelectric cooling means 75. The thermoelectric cooling means consists of an array of planar peltier cooling elements which develops a temperature gradient there across which, with reference to the heat exchanger temperature, is able to cool and re-cool the rubbing element to temperatures as low as −25° C. within a matter of minutes.

Abstract: A wear determining arrangement (30, FIG. 2(a)) for determining wear of a rubbing member of a friction couple, such as an iron brake disc, which is subject to slow wear by frictional engagement by brake pads, comprises a carrier (31) dimensional to overlie the rubbing surface of the disc and be releasably attached thereto by electromagnet (51). The carrier supports a transducer (33), such as magnetic displacement sensor having probe (43), that is mounted on a carriage (36) for scanning the probe across the surface. After an initial scan to map the surface the carrier is removed and re-attached after a period of brake usage, whereupon the surface is scanned again and wear assessed. The rate of wear is normally small, and to ensure that the amount which occurs in a reasonable period can be measured, the carrier is provided with datum projections (46 and 47) and the electromagnet is mounted by way of resilient coupling means (52) to bias the carrier into a stable “tripod” relationship on the surface.