Rearing arrangement for guiding a carriage in a straight line along a guide rail

Claim 1

In combination with a base structure (12) including at least one projection, bearing arrangement for guiding a carriage (2) in a straight line along a guide rail (1) wherein the guide rail (1) is formed with four longitudinal guide tracks (4) thereon; the carriage (2) is longitudinally movable with respect to the guide rail; an interposed longitudinal ball bearing assembly (20) is provided, interposed between the carriage (2) and the guide rail (1), and supporting the carriage on the guide rail, said ball bearing assembly (20) having a plurality of balls (3) for rolling and weight bearing contact with the guide tracks (4) on the guide rail, said assembly including return track means (24, 25, 26) for returning and recirculating unloaded balls in an endless chain around the guide tracks, and wherein the guide rail (1) is formed, at the side of the rail remote from the position of the carriage thereon, with at least two longitudinal parallel ribs (8), defining a longitudinal groove (9) therebetween; at least one projection (11) of the base structure fitting in the groove (9) between said parallel ribs; the carriage (2) has generally C-shaped cross section defining an insertion opening (34), the inside diameter of the insertion opening being larger than the width of the guide rail (1); said ball bearing assembly (20) forming a unitary element including said balls (3), said return track means (24, 25, 26) and ball retention means (23) for retaining the balls on said assembly and retaining said ball captive thereon, comprising a ball race body (21) having ball races (22) thereon, located for operation of the balls between guide tracks (24) on the rail and the ball race 5(22) on said ball race body, said ball race body further having said return track means (24, 25, 26) secured to said ball race body (21) and forming part of said unitary element, said ball retention means being secured to said ball race body and forming part of said unitary element, to retain the balls in and on the respective ball races and in and on said unitary element; said carriage being formed with receiving recesses (30) at either side of the guide rail to receive said ball bearing assembly (20) as a unitary element (20) including said ball race body, and said return track means (24, 25, 26); and matching, engaging, fitting surfaces (28, 29) formed respectively, in said opening (34) of said carriage (2) and the ball race body (21) for positioning of the ball race body, and hence the ball bearing assembly (20) in the carriage upon insertion of the bearing assembly (20) into the carriage and thereby recisely locating the balls (3) between the guide tracks (4) on the rail, and the ball races (22) on the ball race body of the bearing assembly (20).