JPH072387U - Temporary drop prevention device for suspended loads in winches such as cranes - Google Patents

Abstract

(57) [Abstract] [Purpose] An object of the present invention is to provide a device that can prevent a suspended load from temporarily falling when a winch is hoisted or lowered, and to provide a winch such as a safe crane. And [Structure] Pressure oil discharged from a winch motor replenishing hydraulic source to a pressure oil supply circuit to a winch motor 28 is held at a constant pressure by an electromagnetic proportional relief valve 25.
The load of the suspended load according to the working state is calculated by the moment limiter 31 provided with the holding pressure separately, and the signal of the magnitude of the load is sent via the controller 32 to the electromagnetic proportional reset.
It was sent to the valve 25 and controlled to a constant pressure corresponding to the load.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 In winches such as cranes, the temporarily suspended load drops (several mm) when the suspended load is hoisted or unwound. This phenomenon is dangerous because unexpectedly the suspended load falls unintentionally despite the fact that the user tried to hoist it. The present invention relates to a temporary drop prevention device for a suspended load that can avoid such a danger.

[0002]

[Prior art]

 The conventional automatic brake winch mechanism has been designed to reduce the amount of drop in consideration of the timing when the brake is released during winding or winding. That is, at the time of hoisting or lowering operation, when the remote control pressure reaches a certain level, a break release signal is issued to cancel the break. However, since the break release signal is constant, there was a problem that the break was inevitably released and the suspended load dropped before the winch circuit pressure due to changes in the load pressure. More specifically, the holding pressure between the motor and the counter-balance valve decreases while holding the brake, so the brake is released before the circuit pressure rises, and the suspended load is increased. It will fall.

FIG. 1 is a circuit diagram of a conventional general winch mechanism. With this, the operation modes during winding and winding will be described. At the time of hoisting, the oil discharged from the pump 1 is switched by the command of the remote control pressure 10 to the upper side of the switching valve 3, passes through the counter balance valve 4, and is guided to the upper side of the winch motor 5 to reach the winch motor 5. Rotates to the winding side. At this time, the oil discharged from the pump 2 switches the switching valve 7 by the signal of the pressure switch 8 and is guided to the winch break 6 to release the winch break 6.

At the time of winding, as in the case of winding, the switching valve 3 is switched to the winding side by a pressure command from the remote controller 11, pressure oil is guided to the winding side of the winch motor 5, and the winch motor 5 rotates. To be done. The winch break 6 is released by switching the switching valve 7 by the signal 9 of the pressure switch, and the oil from the pump 2 is guided to the winch break 6 to release the winch break 6. In other words, the winch break 6 is effective while the suspended load is held in the air, and the holding side circuit 12 is lowered due to the leakage of the winch motor 5 or the like. When the hoisting or unwinding operation is performed in the suspended load holding posture, the brake is released before the holding side circuit 12 is raised to the pressure equivalent to the holding pressure, and the motor 5 becomes equivalent to the holding pressure. Spin to pressure. This rotation causes the suspended load to drop temporarily.

If the break release signal is delayed, the upper side of the winding can be prevented from falling, but in the case of the lower side, if the release signal is delayed, the counter balance valve 4 is opened first, and then the winch break 6 is released. It is dangerous because the suspended load drops at once.

[0006]

[Problems to be solved by the device]

 In view of the above-mentioned problems of the prior art, a winch such as a safe crane is provided by providing a device capable of preventing a suspended load from temporarily falling when the winch is hoisted or lowered. The purpose is to provide.

[0007]

[Means for Solving the Problems]

 The pressure oil discharged from the winch motor supply hydraulic source to the pressure oil supply circuit to the winch motor 28 is held at a constant pressure by the electromagnetic proportional relief valve 25, and the holding pressure is separately provided. The load of the suspended load is calculated by the ment limiter 31 according to the working condition, and a signal of the magnitude of the load is sent to the electromagnetic proportional relief valve 25 via the controller 32, and the constant pressure corresponding to the load is controlled. -I tried to do it. Further, a hydraulic pressure source for replenishing the winch motor is obtained by dividing the pressure oil discharged from the hydraulic pump 21 into the actuator circuit 23 and the supply circuit 24 to the winch motor 28 by the shunt valve 22.

[0008]

【Example】

 A description will be given based on FIGS. 1 and 2A and 2B. The winch mechanism is the same as the conventional type. The cause of the temporary drop of the suspended load in the conventional mechanism is that the pressure in the holding side circuit 12 between the winch motor 5 and the counter balance valve 4 decreases. The present invention is designed to prevent the pressure in the holding circuit 12 from decreasing. The pressure oil discharged from the existing pump or the additional pump 21 is diverted to the existing actuator circuit 23 and the supply circuit 24 to the winch motor 28 by the shunt valve 22 (when the pump is added, the pressure oil is diverted). Valve 22 is not required). The oil proportionally divided to the oil passage 24 is kept at a constant pressure by an electromagnetic proportional relief valve 25. The electromagnetic proportional relief valve 25 is constantly calculating the load of the suspended load adapted to the working condition by the moment limiter 31 shown in FIG. 3 attached to the machine separately, and the signal of the magnitude of the load is calculated. It is sent to the electromagnetic proportional relief valve 25 via the controller 32, and is controlled to a constant pressure corresponding to the load pressure. The controlled pressure oil is selected for main winding or auxiliary winding by a solenoid valve 26 and is introduced into a circuit between a winch line counter balance valve 27 and a winch motor 28. The check valve 29 is for preventing backflow.

As described above, since the pressure oil corresponding to the holding pressure is supplied between the counter balance valve 27 and the winch motor 28, when the winch is operated up or down, Since the holding pressure equivalent to the load is secured, temporary suspension of the suspended load is completely prevented. Note that the above description has been made only for the winch mechanism, but it can also be applied to a hoisting cylinder, a holding circuit for a telescopic cylinder and the like.

[0010]

【effect】

 The pressure oil discharged from the hydraulic power source for replenishing the winch motor to the pressure supply circuit to the winch motor 28 is held at a constant pressure by the electromagnetic proportional relief valve 25, and the holding pressure is separately provided. The load of the suspended load according to the working state is calculated by the limiter 31, and a signal of the magnitude of the load is sent to the electromagnetic proportional relief valve 25 via the controller 32 to control to a constant pressure corresponding to the load. I tried to do it. Further, the pressure oil discharged from the hydraulic pump 21 of the winch motor replenishing hydraulic source is diverted by the shunt valve 22 to the actuator circuit 23 and the supply circuit 24 to the winch motor 28. As described above, since the pressure oil having the holding pressure corresponding to the holding pressure is constantly supplied between the counter balance valve 27 and the winch motor 28, the hoisted load temporarily drops when the winch is hoisted or lowered. It has become possible to completely prevent this, and it is possible to secure even greater safety during crane loading work.

[Brief description of drawings]

FIG. 1 is a drive circuit diagram of a known winch motor.

FIG. 2A is a drive circuit diagram of a winch motor of the present invention,
(b) shows the pressure control mechanism of the electromagnetic proportional relief valve in (a).

[Explanation of symbols]

21 Hydraulic Pump 22 Dividing Valve 23 Actuator Circuit 24 Supply Circuit 25 Electromagnetic Proportional Relief Valve 26 Solenoid Valve 27 Counterbalance Valve 28 Winch Motor
29 Check valve 31 Moment limiter 32 Controller

Claims (2)

[Scope of utility model registration request] 1. A pressure proportional oil is discharged from a winch motor replenishing hydraulic power source to a pressure oil supply circuit to a winch motor (28) and is held at a constant pressure by an electromagnetic proportional relief valve (25). A moment limiter (31) provided with the holding pressure is used to calculate the load of the suspended load according to the working condition, and a signal of the magnitude of the load is supplied to the electromagnetic proportional relief via the controller (32). Send to the valve (25) and control to a constant pressure equivalent to the load.
Temporary drop prevention device for hanging loads in winches such as cranes, which is characterized in that 2. A supply circuit for supplying pressure oil discharged from a hydraulic pump (21) of a winch motor replenishing hydraulic pressure source to an actuator circuit (23) and a winch motor (28) by a shunt valve (22). 2
A device for temporarily suspending a suspended load in a winch such as a crane according to claim 1, which is obtained by dividing into 4).