SU933617A2 - Hydraulic drive of load-lifting mechanism - Google Patents

Description

(54) HYDRAULIC DRIVE OF LOADING MECHANISM

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FIELD OF THE INVENTION The invention relates to a lifting and transport machinery, in particular to hydraulic actuators of lifting mechanisms.

According to the main author. St. No. 471287 discloses a hydraulic drive of a lifting mechanism, comprising an oil tank with a pump and a hydraulic distributor, connected by means of supply and discharge pipelines to a hydraulic cylinder for lifting the boom, in which, in order to ensure automatic control of the speed of lifting the boom, a return valve, and a control valve, designed as a pressure slide valve, is connected to the discharge pipe below the point of connection of the check valve, parallel to toromu the optional check valve Ei3.

This device does not allow to create the full working pressure in the cylinder cavity of the hydraulic cylinder, which makes it impossible to force the boom downwards. When using such lifting machines, such as excavators, logging machines, often by means of boom and lever mechanisms, they rest in the ground to hang out part of the weight of the machines during repair work and to overcome obstacles or two-way forceful movement of goods.

The purpose of the invention is to expand the operational capabilities of the hydraulic lifting mechanism.

This is achieved by the fact that the hydraulic actuator is equipped with one installed in an additional pipeline connecting the supply and

Q is a discharge pipe, normally closed by a control valve, the control line of which is connected to the feed pipe.

The drawing shows a diagram of the hydraulic drive.

Claims (1)

15 The hydraulic actuator consists of an oil tank 1, a pump 2, a hydraulic distributor 3, a hydraulic cylinder 4, a lifting boom drive or a lever mechanism with a feed 5 and a discharge pipe 6, connected via a pipe 7 7, to which the non-return valve 8 is connected. a control valve 9 is installed, in parallel with which a pipe 10 is connected with a non-return valve 11, and a normally closed control valve 12 with a control line 13 is additionally connected to the pipe 7. The valve 9 is equipped with a control line 14. In the lines Regents 13 and 14 are butterfly dampers 15. Hydraulic works as follows. When lifting or moving light loads, the working fluid pumped from tank 1 by pump 2, valve 3 is directed through pipeline 5 to the thrustless cavity of hydraulic cylinder 4, and since valve 9 is normally closed, working fluid from the hydraulic cavity of hydraulic cylinder 4 flows through pipeline 7 with valves 8 and 12 into its shaftless cavity, providing accelerated movement of the executive body-boom of a load-lifting or lever mechanism for moving the load. At this, the valve 12 is open due to the presence of pressure in the pipeline 5 and the control line 13. The hydraulic cylinder 4. Can also serve to drive clamping levers or power burners, for example, in logging machines. In this case, they are accelerated by closing at low loads. The hydraulic cylinder 4 works with it. a differential circuit with an increased speed of movement of the piston rod. With increasing pressure in the pipeline 5 and the control line 14, due to an increase in the external load on the hydraulic cylinder 4 due to an increase in boom reach, an increase in the load moment or stop of the clamping arms (knives) into the object of labor, the valve 9 opens, the pressure in the pipeline 6 drops, which leads due to the presence of a check valve 8, although the valve 12 remains open. When this drain from the rod end of the hydraulic cylinder takes place through pipe 6 through the valve 3 in the tank 1, and the cylinder 4 operates in the usual way with a lower speed but full force. the defined area of the ground, the adjustment of the safety valve of the hydraulic distributor 3 and the supply of the pump 2, i.e., there is an automatic decrease in speed and an increase in the load capacity or force of the actuator of the mechanism. When the working fluid from the hydraulic distributor 3 is supplied to the pipeline 6, it passes through valve 1 into the cylinder cavity 4 of the hydraulic cylinder 4, which leads to reversal of the executive body of the load-lifting or lever mechanism for moving the load or forcefully unclamping the arms of the object. In this case, due to the connection of the pipeline 5 through the valve 3 with the tank, the pressure in it drops, which leads to the closing of valves 9 and 12 and the possibility of raising the pressure in the squamous cavity to the value of the adjustment of the corresponding safety valve. In this case, the hydraulic cylinder works to retract the rod with full pressure. Valves 9 and 11 with pipeline 10 can be structurally implemented in one unit, for example, in the form of a hydraulic lock, which is installed in pipeline 6. Control lines 13 and 14 can be partially combined and connected to pipeline 5 in one place. The valve 12 can be made, as shown in the diagram, in the form of a hydraulic lock, or in the form of a pressure slide valve with a check valve or a hydraulically extending guide device. All of these options are technically equivalent. The moment of opening of valve 9 and transition from rapid movement to positive pressure is determined by the nature of the change in external load and adjustment of valve 9. As a rule, the opening pressure of valve 9 is set slightly below the adjustment pressure of the safety valve in this system. The opening pressure of the valve 12 should be somewhat higher than the pressure of the free discharge of the working fluid from the rodless cavity of the hydraulic cylinder 4 through the valve 3 to the tank. The parameters of the throttle dampers 15 are selected in such a way as to eliminate sharp transitions of the operation of the hydraulic cylinder 4 from one mode to another, i.e., to reduce the dynamic loads in the hydraulic system. This technical solution allows it to be used in load-bearing mechanisms with reversible power movement of the operating organ. In addition, it can be used in knocking and clamping mechanisms of wood, in order to speed up the working cycle. In all cases of the use of this hydraulic drive, an automatic increase in the speed of movement of the working body at low loads (small load, small tree, idling of the power lever, etc.) is provided. Increasing speed results in shorter cycle times and increased productivity. The invention of the hydraulic lifting mechanism for auth. St. No. 471287, characterized in that, in order to expand the operational capabilities of the hydraulic drive of the load-lifting mechanism, it is equipped with an additional pipeline, connecting the supply and discharge pipelines, normally closed controllable valve, the control line of which is connected to the supply pipeline. Sources of information taken into account during the examination 1. USSR Author's Certificate No. 471287, cl B 66 C 23/42, 22.11.71 (prototype). "5 A at 15. x /four I I / wh  / / / GK1 // b