Abstract: The push-plate of the attachment is guided on left and right pairs of proximal and distal arms. The proximal arms are pivoted at support pivots to the support plate, and the distal arms are pivoted at distal pivots to the push-plate. The proximal arms are pivoted to the distal arms at knee pivots. All three left pivots are parallel to each other, and all three right pivots are parallel to each other. The left pivots all lie at an angle PA to the right pivots. The angle PA is between 80° and 130°. The arrangement is simple and robust, and enables the push-plate to be guided very solidly, over an accurately-straight line path of the push-plate, with no stresses and strains imposed on the pivots by the geometry of the motion.

Abstract: The rotatable fork-plate of a fork lift truck is mounted to a large-diameter slewing gear, and the slewing bearing fits inside. In place of the usual ball bearing, a plastic strip is curved around into a circle, and placed between the slewing gear and the stator frame. The circle is not complete, in that a circumferential gap is left between the ends. The rotor and stator are formed with suitable faces for supporting journal forces, and thrust forces both ways, via the plastic strip. The preferred profile of the strip is channel-shaped. The strip floats circumferentially between the rotor and the stator. The plastic strip being corrosion free, no seals are provided on the bearing, even for operation near sea-water.