GB670641A - Improvements in or relating to hydraulic motors - Google Patents

Abstract

670,641. Liquid-pressure engines. SUTTON, A. M. Dec. 30, 1949 [Jan. 27, 1949], No. 2237/49. Class 69 (ii). In a reciprocating hydraulic motor of constant stroke having a control valve mechanism in which a valve 48, biased towards a position which initiates and sustains a reciprocation of the motor in one direction, is displaced by the motor at the end of that reciprocation to a position which subjects it to a liquid pressure whereby it is displaced further to a position which initiates and sustains a reciprocation in the reverse direction, the motor is arranged at the end of the reverse reciprocation to relieve the valve 48 of the liquid pressure to allow its bias to return it to the original position. The shaft 14 is connected by a rocker 15 to two pistons 16, 17, reciprocable in cylinders 11, 12, respectively, the latter being parallel and in the same plane. Both pistons have cup washers 21 screwed thereto whilst a buffer 24 secured to piston 16 extends beyond the cup washer of that piston. A passage 28 parallel to cylinder 11 has ports 29, 30 and 31 therein, the port 31 opening into the cylinder 11 and the port 29 communicating with an exhaust opening 32. A hollow valve body 36 which is threaded into the upper part of cylinder 11, has its outer end located inwardly of port 29, the body having a port 40 which communicates with passage port 30. Two other valve ports 33 and 34 are provided which communicate with the cylinder 12 and the inlet, respectively. The valve 48 fits within the valve body 36 and is bored from both ends to house springs 56 and 59, the former urging the valve to its inner position and being located at its outer end around a stem 45 of cylinder closing cap 44. Water under pressure enters the inlet port 34 and flows through cut-away portions 41 and 42 in the valve and transfer passage 33 to cylinder 12 and forces piston 17 outwardly. As piston 16 moves inwardly the water therein is forced into the exhaust opening 32 via port 31 as well as openings 58 in the valve 48 and ports 30 and 40 into passage 28, so that when port 31 is closed by pistons 16, water still exhausts via openings 58 and ports 30 and 40. Further travel of the piston 16 causes, firstly; the buffer 24 to slide into the inner bore of the valve 48 and compress the spring 59 and, secondly, the piston itself to contact the inner end of the valve and move it outwardly. Water from the inlet 34 still enters the cylinder 12 but additionally flows through openings 58 and the lower valve bore to cylinder 11, exhaust from the latter being prevented. The water pressure in cylinder 11 causes the valve 48 to move to its extreme outward position whereupon water passes from the inlet port through opening 58 into cylinder 11 to move the piston 16 downwards. At the same time water from cylinder 12 flows through the passage 33 and is directed by the valve to exhaust opening 32 although some water passes into passage 28 and across port 31 to the common space beneath both pistons and so force lubricates the rocker and shaft bearings. The valve 48 remains at its extreme outer position until piston 16 uncovers port 31, i.e. near or at the end of its stroke the sudden drop in pressure then experienced permitting the spring 56 to force the valve to the inner position shown: Compression springs 25 may be fitted to the outer end of each piston in order to assist in the starting of the motor when low water pressure only is available. In a modification, the spring 56 may be eliminated and the inward movement of the valve effected by water pressure. The invention may also be embodied in a single cylinder double-acting motor.