Abstract: An apparatus and method for providing a seal between first and second relatively rotatable parts of machines which operate in an environment comprising dust, grit or other finely divided solid material entrained in air, water or other fluid. The seal includes a rotor and a stator between which there is an annular passage with substantial clearance between the interfacing surfaces defining the passage. The solid material entrained in the fluid which enters the annular passage is deposited in layers on the interfacing surfaces when the mechanism is in use. The layers substantially reduced the cross sectional size of the annular passage and restrict flow of the fluid there through. The annular passage may be rendered tortuous by providing the rotor with annular fins which in use project into annular recesses in the stator, and vice versa.

Abstract: A road marker stud of cat's eye is made of a rubber housing and is to be adhered to the road surface. The housing is provided with surface channels or cavities which divide it into substantially independent flex zones.At least one reflector element is housed in a side face of the housing, the side face extending parallel to one of the channels or cavities. The stresses of impacting wheels are thereby better accommodated.