摘要 |
A linear actuator for a machine, particularly a bending press, comprises first and second bodies (2, 4) mounted for sliding relative to each other and a male-and-female screw mechanism (14) for controlling a relative sliding movement of the two bodies along a working line. The male screw (16) and the female screw (27) are supported for rotation by the first and second bodies (2, 4) and can be rotated by respective electric motors (24, 38). The motors (24, 38) are associated with respective speed-reduction devices (22, 26 and respectively 36) having substantially different reduction ratios. The actuator further includes a braking device (42, 44) associated with the member of the male-and-female screw mechanism (14) which is connected to the speed reduction device (22, 26) with the lower reduction ratio. |