| 摘要 |
A weighing machine for direct measurement of the weight of a load comprises a piston/cylinder mechanism which is arranged between a lifting device 1 and a load carrier 2 and the piston 8 of which is arranged in a chamber 6 forming part of a hydraulic system which comprises a pump 12, a tank 13 and a pressure sensor 18. The chamber 6 communicates with the pressure sensor 18 via a first line 14 and with the tank 13 via a second line 15. In the latter, there is a first valve 11 which is automatically opened when the load carrier 2 is relieved and closed when the load carrier is loaded. In the first line 14, there is a non-return valve 16 which is automatically closed as soon as the pressure in the first line 14 exceeds the pressure from the pump 12. The pressure sensor 18 is arranged in one of the line portions 14 which portions extend between the two valves 11, 16. Hydraulic oil can flow freely in the system when the load carrier 2 is relieved, while said line portions are shut off automatically from that part of the hydraulic system which includes the pump and the tank as soon as the load carrier is loaded. <IMAGE> |
