Heavy duty hydraulic weighing apparatus

Claim 1

In a hydraulic weighing apparatus which includes a piston, an annular ring fixed with and encircling the piston, a cooperating cylinder which fits radially between the ring and piston for receiving the piston in freely interfittable, relatively reciprocally movable relation, and a flexible diaphragm of fluid impervious material sealed in the cylinder and overlying the piston to form a fluid pressure receiving chamber therebetween which is adapted for fluid communication with an indicating device; a bearing arrangement for facilitating free relative reciprocal movement between the piston and ring and the cylinder comprising: A. a plurality of cylindrical raceways, a first portion of each raceway being defined in the outer wall of the cylinder and a second portion of each raceway being defined in the inner wall of the ring; B. a first bearing insert at least partially lining each of said first raceway portions; C. a second bearing insert at least partially lining each of said second raceway portions; each of said first and second bearing inserts comprising a hardened, arcuate strip having an angular dimension less than the angular dimension of said raceway portion which said insert lines, said insert being recessed into said raceway portion and having two opposing edges extending substantially parallel to the axis about which said strip is arcuate, said raceway portion circumferentially extending beyond and abutting said opposing insert edges to form webs that firmly lock said insert therein; D. ball bearing means disposed in each raceway; and E. means for positioning each ball bearing means to contact said first and second bearing inserts in each raceway.