| 摘要 |
The present invention relates to a hoisting gear for patient-lifting device whereby a plunger device (6) is displaceably mounted in a hydraulic cylinder (4), is supporting patient-carrier means (3) such as a seat or a patient-carrying plate and is raisable my means of a pump device (8) provided to move hydraulic oil between two hydraulic-cylinder chambers (9a, 9b) separated by the plunger device, and whereby a lowering device (39) is provided to permit lowering of the plunger device by producing a counter flow of hydraulic oil between the hydraulic-cylinder chambers. In order to obtain by simple means an automatic limitation of the height of the lift the hoisting gear is characterized in that the hydraulic cylinder (4) is on top provided with a stop device (27) limiting the upwards movement of pressure means (22) forming part of the lowering device (39), whereby a valve device (23 and/or 24) mounted on the plunger device (6) reaches said pressure means when said plunger device continues in an upwards direction so that the pressure means (22) controls the valve device to open a counter-flow passage (25 and/or 26) between the hydaulic-cylinder chambers (9a, 9b). |
