Abstract: A steering assistance device for a castor comprises a cam portion (39) having a lobe (41) which is fixed to the bottom of the fixing bolt of the castor and which is surrounded by a closed portion (43) of a capture device (42). The lobe (41) is engaged in an arcuate recess (49) of the capture device (42) in the dead center position of the castor. The capture device (42) is formed of a plastics material and its sides and ends are resilient slats. The arcuate recess (49) is in one end and the two sides (50 and 52) carry inwardly projecting arms (51 and 53).

Abstract: A castor comprises a fork (10) carrying an axle (11) which extends through an aperture in both limbs (12 and 13) and by which a single wheel comprising two discs (14 and 15) is mounted on the fork (10). A roller bearing (22) is mounted on the axle (11). Each disc, (14, 15) comprises a radially outwardly extending annular disc portion (23, 24) and a tubular portion (25, 26) which projects to one side of the respective disc portion (23, 24). The tubular portions (25 and 26) are snap-fitted together, one within the other, and together form the single wheel which has two rims (27 and 28). The roller bearing (22) is fitted into the bore of the tubular portion (26) whereby the single wheel is supported thereon for rotation. The tubular portion (26) provides a plain bearing support for the tubular portion (25) of the other disc (14). Relative angular movement between the discs (14 and 15) is possible because of that.