초록 ▼

An overtravel stop for a rotary shaft (12) is disclosed having first and second embodiments. In the first embodiment, braking torque for the shaft is supplied by the restriction by valve (14) of at least hydraulic fluid flowing in low pressure hydraulic fluid return line (18) from a hydraulic motor

An overtravel stop for a rotary shaft (12) is disclosed having first and second embodiments. In the first embodiment, braking torque for the shaft is supplied by the restriction by valve (14) of at least hydraulic fluid flowing in low pressure hydraulic fluid return line (18) from a hydraulic motor (22) which is connected to the shaft by a drive unit (24) in response to movement of a movable stop (34, 36) to a travel limit along an axial travel path to stop the hydraulic motor. In the second embodiment, braking torque for the shaft is supplied by a combination of a mechanical stop produced by the interaction of stop jaws (82, 84) which are respectively carried by an axially movable annular member (32) and a fixed stop (86) and the restriction of at least the low pressure hydraulic return fluid line (18) by a valve (14). The second embodiment achieves precise final positioning of the shaft by using the mechanical stop to establish the final shaft position and permits the load bearing capacity of the mechanical stops to be downsized as a consequence of substantial braking torque being applied by the hydraulic motor.

대표청구항 ▼

An overtravel stop for a rotary shaft comprising: a fixed stop having at least one stop jaw; a movable stop which rotates with the shaft within an axial travel path along the shaft having a pair of travel limits and having at least one stop jaw; means for causing the at least one stop jaw of the mov

An overtravel stop for a rotary shaft comprising: a fixed stop having at least one stop jaw; a movable stop which rotates with the shaft within an axial travel path along the shaft having a pair of travel limits and having at least one stop jaw; means for causing the at least one stop jaw of the movable stop to engage the at least one stop jaw of the fixed stop when the movable stop has reached one of the axial travel limits to stop the shaft; the at least one stop jaw of the movable and fixed stops upon engagement applying a first braking torque to the shaft; a hydraulic motor having a drive shaft for rotatably driving the shaft; a source of pressurized hydraulic fluid in fluid connection with the hydraulic motor for causing the hydraulic motor to rotate when pressurized hydraulic fluid is coupled thereto; a valve disposed in fluid connection at least between a low pressure discharge port of the hydraulic motor and a low pressure return port of the source of pressurized hydraulic fluid, the valve having a control movable between a first position which permits unrestricted flow of hydraulic fluid between a high pressure port of the source of pressurized hydraulic fluid and a high pressure port of the hydraulic motor and the low pressure discharge port and the low pressure return port and a second position which blocks at least the return of hydraulic fluid to the low pressure return port; and control means, associated with the movable stop and the control of the valve, for causing the control of the valve to move to the second position in response to the movable stop reaching one travel limit within the axial travel path to cause the shaft to have a second braking torque applied thereto by the hydraulic motor.