Brake plate

#The present invention relates to a brake plate, and in particular, but not exclusively, to a brake plate for use in a wet brake system.

#The Applicant is the proprietor of various inventions relating to wet brake systems and components thereof as described, for example, in International Application Nos. PCT/AU92/00540, PCT/AU95/00529 and PCT/AU97/00500, the contents of which are incorporated herein by way of reference.

#In broad terms, a wet brake system typically includes a disc fixed to rotate with a rotating component such as an axle, and a pair of brake pads, one on each side of the disc, with the disc and brake pads disposed within a seal housing containing a volume of oil.

#FIG. 1a is a plan view of a brake plate in accordance with the present invention;

#FIG. 1b is a view of section 1-1 of FIG. 1a;

#FIG. 2a is a plan view of one embodiment of a brake pad incorporated in the brake plate;

#Referring to the accompanying drawings and in particular, FIGS. 1a and 1b, an embodiment of the brake plate 10 is shown as including a plate body 12 with a braking surface 14 on one radial face 16 of the plate body 12. At least one (in this particular embodiment four) scraper or wiper means 18a-18d (hereinafter referred to in general as “scrapers 18”) is supported by the plate body 12. The scrapers 18 are moveable axially between a first position where the scrapers 18 extend axially beyond the braking surface 14, as depicted in FIG. 1b, and a second position where the scrapers 18 are substantially flush with or below the braking surfaces 14.

#Each of the scrapers 18 has a substantially planar contact face 20 for face to face contact with a disc 22 in a disc brake system (see FIG. 4). Contact face 20 has a peripheral surface which is made up of a first lateral (or an inner circumferential) edge 26, a second lateral (or outer circumferential) edge 28, and opposite first and second radial edges 30 and 32 extending between the edges 26 and 28. A groove 34 is formed on the contact face 20 to provide a fluid flow path between two spaced apart points on thet peripheral edge of the contact face 20. In this particular embodiment, the groove 34 extends between and opens onto respective points on the edges 26 and 28 of the contact face 20.

#Each of the scrapers 18 is in the form of a generally rectangular shaped block 36 of a wear resistant, and preferably self-lubricating, material such as PTFE or PTFE impregnated with boron or manganese bronze. Each block 36 is housed within a respective cavity 38 formed between a back plate 40 and front plate 42 of the plate body 12. The front plate 42 is provided with a plurality of apertures 44 through which the contact face 20 of respective scrapers 18 can extend. The width and breadth of the apertures 44 are smaller than the corresponding dimensions of the cavities 38. Each block 36 is provided with a laterally extending peripheral skirt 48 which is configured and dimensioned so as to be able to slide axially within cavity 38 but unable to pass through aperture 44. In this way, the scrapers 18 are retained to move axially within the cavities 38 of the brake plate 12.