FI74116C - Hydraulic high-speed circuit - Google Patents

Description

1 74116

The present invention relates to a hydraulic circuit for providing a rapid movement for a second direction of movement of a double-acting cylinder or a similar actuator, in which circuit both working lines of the cylinder are connected to each other by means of a shut-off valve.

If a high piston-out stroke speed is desired for the cylinder, differential coupling is often utilized, in which the oil returning from the piston rod side of the cylinder 10 is usually led back behind the cylinder piston via a directional valve.

Here are a few examples of problems with known systems. A disadvantage of a system in which the differential connection is provided by a 4/3 or similar directional valve is that the directional valve has to be dimensioned large because it has to pass through both the pump output and the amount of oil returning from the piston rod side. On the other hand, the directional valve is often located far from the actuator, i.e. the hydraulic cylinder, in which case the long piping between them, intended for a large volume flow, has to be dimensioned large.

Another disadvantage often associated with differential couplings is that the retention of the piston is not ensured by an external force acting on it in either direction.

When attempting to make a differential connection in the conventional manner by means of pressure, flow and check valves, the disadvantage is often that the connection only works, for example, with certain well-defined pressure settings. The system is not completely reliable in all conditions, but is sensitive to pressure settings or valve leaks, for example. A further disadvantage of some known differential connections is that an additional control pressure line or more is required between the quick-acting valves and the cylinder directional control valve. The leakage lines required from the light to the tank are also detrimental as they increase costs.

It is further disadvantageous if pi ka 1i i ke requires an additional 35 magnets in the valve.

The object of the present invention is to eliminate the above-mentioned drawbacks and to provide a simple and reliable hydraulic circuit for providing rapid movement.

The object is achieved in the hydraulic circuit 5 according to the invention in such a way that the shut-off valve is controlled by the control piston reciprocally so that the larger line when the working line is facing the cylinder, after the control pressure branch, there is a counter-valve to enter the cylinder and then a branch to the shut-off valve.

Other suitable embodiments of the invention are set out in the dependent claims.

15 In this connection, a situation is considered in which an external force tends to pull the piston outwards and it is desired to prevent the dangerous situation following the rupture of the pipe leading to the ring-surface side of the cylinder. Many known quick-acting connections require a separate pipe break valve to prevent an accident, which incurs 20 additional costs.

An embodiment of the invention will now be described in more detail with reference to the drawing. The content of the drawing is as follows: The hydraulic circuit according to the invention is applied in the hydraulic system of Fig. 1. In the embodiment of the invention shown in Fig. 2, the quick-acting circuit is formed into a single-speed quick-acting valve.

The hydraulic system of the drawing comprises a volume flow source 1, a directional valve 2, a cylinder 7, a tank 16, as well as a quick-motion circuit and the necessary piping.

When the directional valve 2 is in its central position, the holding of the cylinder 7 against the forces pushing the piston 14 inwards is ensured by the closed central position of the directional valve. Even if the shut-off valve 13 then opens, the cylinder piston 14 remains in place due to the cross-sectional area of the piston rod. If an external force tends to pull the piston 14 outwards when the directional valve 2 is in the middle position-35, the shut-off valve 13 closes leak-free due to spring and pressure

T

3 741 1 6 closed, preventing the piston 14 from flowing outwards, even if an external force acts for a long time.

When the left-hand operating position of the directional control valve 2 is engaged, the pressure of the system can act via the work line 3 and 5 5 on the opening side 8 of the control piston 15, opening the shut-off valve 13.

The shut-off valve can open freely, because at the same time the other side 9 of the control piston can be connected to the tank 16 via the line 4 and the directional valve 2. The non-return valve 11 remains closed by means of a spring and pressure. In this way, a rapid movement in the piston-out direction is provided, since the liquid returning from the piston rod side 19 of the cylinder 10 can freely return to the rear of the cylinder piston via the connection 17 and the line 5.

When the right-hand operating position of the directional control valve 2 is engaged, the pressure fluid enters the working line 4, the connection 18 and through the non-return valve 11 to the piston rod side of the cylinder. At the same time, since there is a connection to the tank via the line 3 and the directional valve 2 behind the piston of the cylinder 15, the cylinder piston 14 now moves inwards. Since the shut-off side 9 of the control piston 15 is now under pressure and the opposite side 8 of the control piston is in communication with the tank, the shut-off valve 13 will remain securely closed in this situation.

The drawing and the related explanation are only intended to illustrate the idea of the invention. The details of the hydraulic circuit and the quick-acting valve according to the invention can vary considerably even within the scope of the claims.

Claims (3)

74116 A hydraulic circuit for providing rapid movement for a second direction of movement of a double-acting cylinder (7) or a similar actuator, 5 in which each cylinder working line (3 and 4) is connected via a shut-off valve (13), characterized in that the shut-off valve is reciprocally controlled by a control piston that the larger surface area working line (3) of the cylinder is connected to the opening side (8) of the steering piston and the closing 10 or closing side (9) of the steering piston is connected to a working line (4) leading to a smaller surface area side of the cylinder. after the control pressure branch (10), the non-return valve part (11) entering the cylinder and then the branch (12) closing valve i1 il le (13). Fast-moving circuit constructed of standard hydraulic components by piping as described in claim 1, characterized in that the components are located in the immediate vicinity of the hydraulic cylinder (7), the circuit preventing the piston (14) from rushing in the event of a smaller cylinder area. the pipe (4) leading to the side breaks. Pi ka1i i light (1) constructed as a unit as described in claim 1, characterized in that the quick-acting valve is located in the immediate vicinity of the hydraulic cylinder (7), whereby the pi kai i iii also acts as a pipe break valve in the event of the piston rushing, that the pipe (4) leading from the machine to the smaller area of the cylinder is broken. I: