| 摘要 |
A control device for the descent of a load, comprising: a first conduit (2), designed to connect a first chamber (C1) of a cylinder (C) with a directional control valve (D); a second conduit (3), designed to connect a second chamber (C2) of the cylinder (C) with the directional control valve (D); a control valve (4), disposed along the first conduit (2), which is designed to allow the flow of fluid from the directional control valve (D) toward the first chamber (C1) and to allow the flow of fluid from the first chamber (C1) toward the directional control valve (D) only if supplied with a pilot pressure that is greater than a minimum value; a shut-off valve (5), disposed along the second conduit (3), which is designed to take on a closed configuration, in which it prevents the flow of fluid along the second conduit (3), and an open condition, in which it enables the flow of fluid from the directional control valve (D) toward the second chamber (C2) only if the pressure present between the shut-off valve (5) and the directional control valve (D) exceeds a given minimum pressure; a pilot conduit (6), which connects the control valve (4) with the section of the second conduit (3) between the shut-off valve (5) and the directional control valve (D); a drainage conduit (7) which connects the section of the second conduit (3) between the shut-off valve (5) and the second chamber (C2) with a drain (T); a one-way valve (8), disposed along the drainage conduit, which prevents flow from the drain (T) toward the second conduit (3) and allows flow from the second conduit (3) toward the drain only if the pressure upstream of the one-way valve (8) exceeds a given minimum pressure; a choke (13), disposed in parallel with the shut-off valve (5). |
