FI90584C - Method and apparatus for conducting a pressure medium to actuators - Google Patents

Description

90584

METHOD AND EQUIPMENT FOR PRESSURE MEDIA CONTROL FOR ACTUATORS - F6RFARANDE OCH ANORDNINGAR F6R ATT LEDA TRYCKMEDIUM TILL AKTIVATORER

The invention relates to a plurality of actuating machines and devices with a pressurized medium, such as hydraulic cylinders. According to the invention, the discharge of a high-pressure medium into a low pressure or free space without work is prevented or reduced.

It is previously known as a device using a pressure medium, e.g. timber cranes in which two or more booms connected in succession are moved by means of hydraulic cylinders. During lifting and loading movements, two or more cylinders are often used simultaneously. In practice, this means that the pump pressure and volume flow are sufficient for at least two cylinders at the same time. As a result, the crane is equipped with a high-output pump and correspondingly high motor power is required to operate the pump. In addition, the cranes also have a number of other devices with much lower flow, which are often used on their own. Such are e.g. crane mast rounding and timber grapple wheel tysla ite.

In cranes, the pressure medium piping is led directly from the control valve i to the cylinder, whereby all cylinders are independent and the media returning from the cylinders are discharged into the return line leading to the hydraulic fluid, even if the medium has a high pressure and flow rate. The pressure energy of the medium is lost more or less, regardless of the fact that it could be utilized at that very moment. As a result of the current arrangement, a high-yield pump and a high-performance pump drive must be selected for the devices.

The solution according to the invention avoids these drawbacks and the invention is characterized by what is stated in the claims.

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The main advantage of the invention can be considered that the circulating pump which generates pressure in the fluid and its drive motor can be dimensioned even smaller, because the movements of actuators requiring a high medium flow can be combined so that the second actuator can be controlled. In addition, by thus combining the two functions and performing simultaneous 1-yoke performance, their 1 i yoke performances become interdependent and a large administrative advantage is achieved in the execution of repeated 1 i yoke sets in a controlled manner.

In the following, the invention will be explained in more detail with reference to the accompanying drawing, in which

Figure 1 shows a crane with booms.

Fig. 2 shows a pressure piping connection for the cylinders of the crane according to Fig. 1.

Figure 1 shows a timber crane 1 rotating on a column 2 with booms 3 and 4. The boom 3 is moved by a cylinder 5 and the boom 4 is moved by a cylinder 6. The cylinder 5 is single-acting and the cylinder 6 is double-acting, pipes 7, 8 and 9 are hydraulic tubes. By far the most common function of this structure is that the cylinders 5 and 6 operate simultaneously. As the second cylinder 5 lengthens, the other 6 also lengthens, and as the other shortens, the other also shortens. This is the case when the crane is used to reach and move the grapple 17 further and take the load and move it closer, as well as when the load is moved further. In the structure shown in Fig. 1, in use, the pressure hoses 7 and 9 always have some pressure even in the absence of a load. When the trough 17 is tipped to be flattened almost horizontally, the cylinders 5 and 6 then operate simultaneously and in the bending situation of the booms it is possible to direct the pressure fluid from the pressure hose 9 to the cylinder 5 because a lower pressure prevails in the hose 7. A considerably high pressure is created in the liquid leaving the hose 9, because the pressure is increased by both the grapple and the weight of the boom 4 and the pressure 90904 applied in the cylinder 6 along the hose 8 to the other side of the piston. The figure also shows a boom extension cylinder 18.

In the case of straightening the boom, in which case the grapple is moved further away, a pressurized fluid is available from the cylinder 5. This can then be led along the hose 9 to shorten the cylinder 6, albeit depending on the cross-sectional areas of the cylinders.

The pressurized fluids to be utilized can be led directly to the other cylinders 11e or they can, whenever possible, be led to the pressure side of the hydraulic pump 11, in which case they benefit any function.

Figure 2 shows a pressure pipe connection for utilizing the pressurized medium leaving the cylinder. The diagram shows a valve 10 from which the pressure pipes 7,8,9 are sent to cylinders 5 and 6. The pressure for the valves (not shown) in the valve comes from the pump 11. Along the return line 12, the pressurized liquid returns to the pump via the liquid tank. In the exemplary solution according to the figure, the pressure generated in the hose 9 is applied to the elongation movement of the cylinder 5. In the piping, a pressure-controlled valve 14 and a directional valve i 1 and 15 are used in the line leading to the cylinder 5. The pressure-controlled valve 14 prevents the cylinder 6 from being unduly elongated. Elongation and conduction of the return fluid to the cylinder 5 is only permitted when pressure is applied to the cylinder 6 through the hose 8. The directional valve i 1 i 13 prevents the discharge of pressurized liquid through the valve i 1 to the return line 12. The dashed line 16 shows an alternative way of utilizing the pressurized liquid by directing it to the pressure side of the pump 11 to increase the volume flow of the pump. In this alternative, the cylinder 5 receives the utilized flow from the total fluid flow through the valve 10. Figure 2 shows a diagram of the utilization of the return fluid of only one cylinder, but the return fluid of other cylinders and actuators can also be led to the supply fluid of the other actuators by a corresponding connection, if only the pressure generated is sufficient. Such a cylinder is, of course, a cylinder 5 and also a cylinder 18 of Fig. 1, which, e.g. in an active device.

In utilizing the invention, the valves (as in Figure 2) can be electrically controlled, so that they can be easily switched on or off. In such a structure, the energy-saving method according to the invention can be quickly switched to operation when the conditions are met and, correspondingly, it is also possible to quickly switch to the traditional actuator control method when such is desired.

By means of the invention, it is possible to reduce, for example, the capacity of a hydraulic pump and also the need for power. In the application of the invention, too, the heating of the hydraulic fluid does not become such a problem as in current systems which operate at a high volumetric flow and in which all the fluid circulates through the pump.

The invention is not limited to the crane shown, but can be modified within the scope of the inventive idea set out in the claims. The invention can be applied to several devices using compressed air or compressed liquid, in which case the actuator can be a cylinder, a turbine, a pump or a motor. It is essential that the pressure in the medium is formed or maintained in the medium in such a way that it can be further utilized. Pressure can be caused by gravity, braking motion, slowness of mass, etc.

Claims (10)

A method for conveying a pressurized medium discharged from a dirt to utilization in devices, in particular cranes (1), loaders and excavators, comprising at least two actuators (5) operating differently with the medium (1), which are connected to one or more, (6) the pressure of the medium resulting from the external force, load or gravity is conducted as a pressurized volume flow to one or more other actuators operating with a pressure medium performing a different type of work, when said pressurized volume flow is directed away from the first-mentioned actuator / devices. Method according to Claim 1, characterized in that the pressure medium is introduced into another pressure line (7) leading to the actuator (5). A method according to claim 1, characterized in that the pressure medium is led to the volume side of the pressure medium to be fed to the pressure side of the pressure generator (11). A method according to claims 1-3, characterized in that the utilization of said outlet pressure medium in other actuators is limited and / or controlled by means of valves. Method according to Claims 1 to 4, characterized in that the volume flow of the pressurized medium applied to the actuators at a moment 11 or in part or in full 1 exceeds the volume flow output of the pressure generator (11). 5,90584 Method according to Claims 1 to 5, characterized in that cylinders, motors, pumps, turbines or the like operated by the medium 1a are used as actuators. 6 90584 7. Equipment for pressure range a i nee 1la operating cranes, excavator machines, etc. corresponding to different devices, for carrying out the method according to claim 1, characterized in that the device comprises pressure medium piping from one or more actuators (6) for conducting the pressurized medium from one or more other stages to one or more other types. , which has a lower supply pressure or which currently has a lower pressure in the supply line. Apparatus according to claim 7, characterized in that the apparatus comprises pressure medium piping between the actuators (5, 6) provided with pressure or flow control means (13, 14, 15). Apparatus according to claim 7 or 8, characterized in that the apparatus comprises electrically controlled valves in pressure medium pipelines. Apparatus according to one of the preceding claims 7 to 9, characterized in that it comprises a pressure medium piping (16) from at least one actuator on the pressure side of the pressure generator (11). 1 90584