| 摘要 |
A gearing (1) includes a toothed rack (4) arranged in the cylindrical tube (2) of a hydraulic cylinder (3) and carrying at both ends pistons (21, 22) which fit tightly inside the cylindrical tube (2). The cylindrical tube (2) which works as a driving rod pivots around the axe (8) of the fixed toothed wheel (5), a movable toothed wheel (11) pivoting on the cylindrical tube (2) at a distance from the fixed toothed wheel (5). A swivelling lever (14) is fixed to the mobile toothed wheel (11). Both toothed wheels (5, 11) pass through slots (17, 18) in the cylindrical tube (2) of the hydraulic cylinder (3) and engage the toothed rack (4). When parallel motion is to be achieved, the distance between the geometric axes (8', 12') of both toothed wheels (5, 11) is the same as the length of the swivelling lever (14), and the radius of the fixed toothed wheel (5) is twice as long as the radius of the movable toothed wheel (11). |
