| 摘要 |
1,252,581. Reciprocating motors. BUTTERWORTH HYDRAULIC DEVELOPMENTS Ltd. Jan.28, 1969 LFeb. 12, 1968], No.6796/68. Headings F1A, F1M and F1P. In a fluid operated motor a piston 4 is moved in a direction Y at a faster rate than in the reverse direction by connecting the pressure chamber 6 with two sources of fluid-pressure and chamber 7 with exhaust, and connecting chamber 7 with only one source of pressure and chamber 6 with exhaust in the reverse direction. Fig. 1 shows a spool valve 8 having a stepped piston 9 reciprocated in a stepped bore 10 and having its smaller diameter working face exposed to a pressure chamber 12 connected to a source of constant pressure, and its larger face exposed to pressure chamber 14 which is alternately connected with a source of pressure and exhaust. In the position shown, chamber 6 is connected via a control port 34 and a bore: 40 in spool 9, connecting two transfer chambers 24, 22 to two sources of pressure 38a, 39a which may be two independent pumps or a multiple outlet pump in which variation of outflow of one outlet is independent of the other, and chamber 7 communicates via transfer chamber 25 and control port 35 with exhaust passage 31. When chamber 14 is exhausted, spool 9 moves to the right and source 38a and port 34 are opened to exhaust by the movement of lands 16 and 18 respectively, and control port 34 is uncovered by land 19 to connect chamber 7 with source 39a to move the piston 4 in the reverse direction. It is stated that reciprocation of the spool can be controlled by the opening and closing of ports in the piston cylinder 3 by control surfaces on the piston 4. |
