JPS648369A - Reciprocating motion changeover device for pump - Google Patents

Abstract

PURPOSE:To reduce the number of parts, and to facilitate assembling work, and further to enhance durability, by making a spring, by which a changeover operating body changing over the supply and discharge of operating fluid is pressed in respective changeover positions on one side and on the other side, a special-shape wire spring. CONSTITUTION:In the inside of a changeover device body 41, a changeover mechanism part 44 by which the operating fluid to be alternately supplied to or discharge from either of two operating fluid chambers 42, 43 is changeover-controlled is provided. In the changeover mechanism part 44 an operating rod 45 is reciprocatatably inserted. In the operating rod 45, a sleeve-shaped changeover operating body 61 which is moved from the changeover position on one side to that on the other side in relation to the reciprocating motion is loosely fitted, and in the changeover operating body 61 valves 91, 92 and 94 for changing over the supply and discharge of operating fluid are provided. While the changeover operating body 61 is pressed in respective changeover positions by springs 71 which provide an elastic pressing force in the orthogonal directions at the neutral position, this spring 71 is made of a wire spring of nearly C-shaped form in which both ends of the wire rod is bent in the direction so as to face each other.