| 摘要 |
<p>The means comprises a variable resistance (R1), two set resistances and two comparing members which compare the variable resistance to these set resistances and give a control signal to the control valve of the working cylinder when the value of the variable resistance (R1) is the same as the value of either one of the set resistances. The variable resistance (R1) is arranged adjacent to the path of movement of the piston in the working cylinder and comprises a resistance element (4) and a strip of magnetic material (5) which is located on the opposite side of the resistance element (4) relative to the piston and which has laterally projecting flexible transverse strips (6). A part (3) of the piston is formed as a magnet whereby, as the piston moves along the adjusting resistance, said transverse strips (6) are successively bent into engagement with the resistance element (4) and, accordingly, the value of the resistance changes as the piston moves therealong. </p> |
