GB803984A - Improvements in or relating to liquid spring - Google Patents

Abstract

803,984. Liquid springs. CLEVELAND PNEUMATIC TOOL CO. Oct. 29,1956 [Jan. 23, 1956], No. 32891/56. Class 108(3) A liquid spring comprises a source 33 of pressure liquid maintained at a predetermined pressure, and valved means 56 (Fig. 3) operable by relative movement of the plunger 12 and working cylinder 10 of the spring, to a predetermined position, to provide fluid flow in both directions between the source of pressure liquid and the cylinder 10, the pressure in the cylinder 10 and in the source 33 being equalized each time the plunger 12 and cylinder 10 reach their predetermined position. The valve 56 comprises a piston valve member slidable in a bore formed in one of the pegs 19a of the three pegs 19 of an unsupported-area type gland for the plunger 12. The valve 56 is outwardly urged by a coil spring 58 to a position in which it cuts off the connection between a port 62 leading to the interior of the valve 52, and a port 42 leading via a passage 41 to a reservoir 29 forming the source 33. When the valve 56 is in this position it connects the port 42 (by means of an annular channel 61) with a. port 46 leading to the plunger 12 at a position between the high pressure seal ring 14 of the gland 13 and a low pressure seal ring 44. The liquid in the reservoir 29 is put under pressure by a piston 31 acted on by a coil spring 39. The piston 31 carries an indicating scale 34. In operation, when the plunger 12 of the liquid spring moves into its fully extended position, a ring 63 rigid with the plunger 12, comes into engagement with a projecting stem 57, rigid with the valve 56, and thus moves the latter against the spring 58 into the position in which it connects the reservoir 29 with the cylinder 10.