DE3050174C2 - Hydraulic control circuit of a hydraulically operated crane - Google Patents

Description

The invention relates to a hydraulic control circuit of a hydraulically operated crane according to the preamble of claim 1.

From DE-AS 25 01 753 a hydraulic control is known in which both the remote and the Manual operation is assigned a single control valve.

The invention is based on the object of providing a hydraulic control circuit of a hydraulically actuatable To create a crane with the possibility of an independent manual and remote control with simple means ensures a safe emergency stop or slow operation.

According to the invention, this object is achieved by the features of the characterizing part of the patent claim 1 solved.

According to this solution, manually operated directional control valves and remote-controlled valves are next to one another Directional control valves provided. The delivery openings of the directional control valves are equipped with servomotors connected and the manually operable directional control valves form one in their neutral position Central bypass between the oil pump and at least one of the inlet openings of the remote-controlled directional control valves. When none of the manually operated directional control valves are operated, i.e. H. in the neutral position is located, the center bypass is guaranteed and it can be via this center bypass line remote control of the actuators can be carried out. If one of the manual directional control valves is shifted from the neutral position, this center bypass line is blocked and there is only one manual actuation of the servomotors made.

If, however, the direction control valve 17 and the direction control valve 17-1 are actuated at the same time, this means an emergency stop of this servomotor. The assignment of the directional control valves according to the invention also enables slow or creeping operation. With a certain simultaneous actuation of certain directional control valves which are assigned to a certain servomotor, either an emergency stop or a slow operation can therefore be carried out, while with separate actuation either a "remote or manual operation can be carried out. This means that with manual actuation one of the directional control valves cannot be remotely controlled for the other directional control valves.
Further advantageous refinements emerge from the subclaims.

The invention is explained in more detail below with reference to the drawings. It shows

F i g. 1, a hydraulic circuit of the hydraulic crane and

F i g. 2 and 3 are explanatory views showing an application example of the hydraulic crane with a hydraulic circuit demonstrate.

F i g. 1 shows a hydraulic circuit of a hydraulic crane, in FIG. 1 an arrangement of manually operated Directional control valves, which are bypassed in their neutral positions, are used to operate servomotors of a crane by switching the hydraulic oil discharged from a pump 4, manually operated Directional control valves with central bypass 12 to 17 are provided for boom cylinders 6, 7, one Swing motor 8, a crane arm telescopic cylinder 9, a winch motor 10 and a crane boom cylinder 11, and their discharge openings are connected to the servomotors via associated lines 19, 20, 21, 22, 23a, 24a, 25a, 25a, 27a, 28a, 29a and 30a connected.

In addition, the inlet openings of the manually operated directional control valves are provided with a central bypass 12 to 17 connected to each other in parallel by a line 39; namely the so-called parallel connection, yes it is possible to form the so-called tandem circuit without using this line 39.

Next, Fig. 2 is an arrangement of solenoid valves for remote control of the crane motors connected to a return line 33 which leads to a reservoir 5 by center bypassing the above-described manually operated directional control valves 12-17 in their neutral positions, and a number of solenoid valves corresponding to Figs The servomotors of the remote-controlled crane are connected in parallel to one another. That is, the invention is provided with directional control solenoid valves 14-1, 15-1, 16-1 and 17-1 corresponding to the swing motor 8, the boom telescopic cylinder 9, the winch motor 10 and the boom cylinder 11, respectively, to be controlled remotely, and their delivery openings are connected to each remote-controlled servomotor via lines 230, 246, 25b, 26b, 27b, 28b, 28b, 29b and 3OZ? tied together.

Reference number 3 is a proportional drain solenoid valve, which is parallel to the directional control solenoid valves. The proportional drain valve is essentially a pressure control valve for controlling a holding pressure of the circuit by control current, but this valve is on the most downstream side of the rear

running line 32 is used and acts as a flow rate control valve, since it controls the pressure of the circuit. That is, the flow rate control of a blowdown system is carried out

In addition, 18 is an ordinary dispensing valve as a safety valve, 33 and 34 are drain lines, 35 is a Equalizing valve and 38 a pilot check valve.

The operation is described as follows.

Manual actuation to

Before the crane starts to work, the crane booms are usually extended to support it. That is, manually operated directional control valves 12 and 13 are switched to 12C and 13C, whereby boom cylinders 6 and 7 are stretched. The crane is then loaded by moving the manually operated directional control valves 14 to 17 to positions C and D , respectively. When these manually operated directional control valves are switched to one position or the other, hydraulic oil flows to the working side and the motor is operated. If in this case one of the control valves is switched, the center bypass is blocked so that no oil flows to the return line 32 and as a result no oil is fed to the directional control solenoid valve assembly 2, and since the directional control solenoid valves 14-1 to 17-1 are in the neutral position are located, the output lines 236 to 30b of the control solenoid valves are in the blocked state when the manually operated control valve 17 is switched to the crane arm cylinder 11 z. B. to operate, the oil that has flown into lines 29a and 30a does not flow into the control solenoid valve 17-1 through lines 296 and 306, and hence each motor 8 to 11 can be operated independently by manually switching all of the manually operated control valves 14 to 17 from the control solenoid valve assembly 2 and the proportional output solenoid valve 3.

Remote control operation

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The manually operated control valves remain in the neutral positions, as in FIG. 1 shown. Then, the oil flows from the pump 4 through the center bypass passages of the hand-operated control valves and into the return line 32. When the solenoid 17b of the solenoid control valve is energized 17-1, the control solenoid valve is shifted to the position 1 1F, and the Krpnarmzylinder 11 is ejected. However, no pressure builds up in line 32 and cylinder 11 is not actuated. Then, when the proportional relief solenoid valve is energized and a control current is gradually increased, the pressure in the line 32 can begin to rise, and the crane arm cylinder 11 is thereby also actuated. In this case, oil that differs from the oil that has flowed into the crane arm cylinder is discharged into the reservoir via the proportional discharge solenoid valve. The proportional discharge solenoid valve 3 is designed so that when the current flowing through the proportional discharge solenoid valve is a maximum fco, the maximum pressure determined by this valve 3 is equal to or greater than the set pressure of the discharge or safety valve 18, so that, if the safety valve 18 does not open, the oil discharged from the pump 4 flows into the crane arm cylinder 11 via the line 306 of the control solenoid valve 17-1 and actuates the crane arm cylinder at a nominal flow rate. That is, the flow rate is controlled by controlling the proportional discharge solenoid valve so that the speed control of each motor of the crane can be easily performed.

The device described is for mutually independent operation in manual mode and in remote control mode built and the following processes are possible by combining these actuations.

Emergency stop

(1) When the crane is operated manually, for example, the manually operated valve 17 is switched to the position 17D, and the crane arm cylinder 11 is extended when the magnet 17a of the solenoid valve 17-1 is energized and the valve to the position YIE in the event of an accident shifts, the oil passes from the line 30a into the oil discharge line 33 and into the reservoir 5 via the line 30i>, so that the stretching movement is stopped. (In this case, when the solenoid 17 £> of the control solenoid valve 17-1 is energized and the valve is switched to position 17F, the oil exits line 30a into line 32 via line 30Z? And is diverted to the reservoir so that the same effect occurs. In this case, however, the proportional drainage solenoid valve 3 should be in the rest position. B., as in FIG. 2, the unloading is carried out in a position not visible to the operator A of the crane, a second worker B can put a line around the obstacle and use a manual control unit C for remote control and observe the process for safety.

(2) When the crane is operated by the remote control, the crane operation can be stopped if the center bypass of the manually operated directional control valve is blocked and the oil flow to the return line 32 side is cut off. That is, the switching process of the manually operated directional control valve, which has no direct relationship to the loading process of the crane, i.e. the manually operated directional control valve 12 or 13, is switched to the position 12C or 13C so that the center bypass is blocked, the outrigger cylinders 6 or 7 are not extended because they are already extended, and the hydraulic oil from the pump 4 passes through the safety or drain valve 18 into the reservoir. The crane operation can then be stopped with remote control. That is, if z. For example, according to FIG. 3, a worker B is on a work platform at the end of the crane arm and works there by actuating the remote control device C, then a monitoring person A can operate an emergency stop.

(3) When the crane is operated by remote control, for example, the magnet \ 7b of the solenoid valve 17-1 is excited so that it changes its position to 17F and the crane arm cylinder 11 is extended. If in this case the manually operated valve 17 is switched against the extension direction of the crane arm cylinder 11 in the retraction or shortening direction, ie in the position 17C, then the center bypass is blocked and the oil flow to the side of the line 32 is stopped and the oil in of the line 30a flows into the reservoir 5 via the position 17C of the manually operated valve 17 and the discharge line 33, while hydraulic oil to flow from the line 39 into the line 29a via the line 296, the position 17F of the control solenoid valve 17-1 and the The discharge line 33 flows to the reservoir 5, with the result that the extension movement of the crane arm cylinder 11 is stopped.

Slow or creep operation

When the crane is operated by remote control, the proportional drain solenoid valve 3 is controlled, to adjust the flow rate flowing into each servomotor by actuating the manually operated directional control valve and to control the amount of flow into the return line 32 so that creeping operation is possible. For example, directional control solenoid valve 17-1 on side 170 is energized and placed in position 17F, the Proportional drain solenoid valve 3 is controlled so that the flowing into the extension side of the crane arm cylinder 11 Oil flow is controlled, and the manually operated direction control valve 17 is in the retraction direction against the stretching direction of the crane arm Linders 11 adjusted, d. H. its direction will be in the position 17C is changed, and as a result, an opening of the pipe provided with the center bypass is narrowed, and the Flow rate that flowed to the side of the line 32 from the manually operated directional control valve 17, can be decreased. That is, double flow rate control is carried out so that a Creep operation can be performed. In this case, when the manually operated directional control valve 17 is completely changed over, then the crane arm cylinder 11 stops in its movement. This is the case of the emergency stop described above (3).

For this purpose 2 sheets of drawings

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Claims (4)

Patent claims: 1. Hydraulic control circuit of a hydraulically operated crane for operating servomotors the same by switching over the hydraulic oil coming from a pump with the aid of directional control valves that deliver the hydraulic oil to the servomotors guide, characterized in that manually operable directional control valves (12-17) are provided that remotely controllable directional control valves (14-1 to 17-1) are provided that the discharge openings of the directional control valves are connected to the servomotors (6-11) that the manually operable directional control valves (12-17) have a center bypass in their neutral position (32) between the oil pump (4) and at least one of the inlet openings of the remote-controlled directional valves Form (14-1, 17-1). 2. Hydraulic control circuit according to claim 1, characterized in that a proportional drain valve (3) is connected in parallel with the directional control valves (12-17 and 14-1 to 17-1). 3. Hydraulic control circuit according to claim 1 or 2, characterized in that the remotely controllable Directional control valves (14-1 to 17-1) are solenoid valves that are in the return circuit of the hydraulic circuit of the crane are connected in parallel. 4. Hydraulic control circuit according to one of claims 1 to 3, characterized in that the Directional control valves are 3-way valves.