JPS583831Y2 - Device to prevent falling off of lifting machine - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a device that prevents a suspended load from falling when it is lifted by a lifting machine.

In general, when working with a suspended load in the air using the hydraulic actuator (hydraulic motor or hydraulic cylinder) of a lifting machine, for example, during installation work such as welding or bolt alignment of steel structures in a yard or indoors, it is necessary to set the load by one inch for safety reasons. It is necessary to hoist the suspended load without lowering it.

Conventionally, a lifting machine as shown in FIG. 1 has been used.

That is, this lifting machine drives a hydraulic actuator (hydraulic motor or hydraulic cylinder) 1 using a control pulp 2 to rotate a drum winch 3 and wind up a wire rope 4 that is stretched through a sheep 5. The suspended load 7 is lifted through the hook 6, and then the holding brake 8 is operated by a solenoid valve (switching valve) 9 to stop the drum wiener 3 and the suspended load 7 is suspended in the air.

In the figure, 10 indicates counterbalance pulp.

By pressing the button on such a lifting machine, relying on the operating skills of the driver,
By adjusting the timing with the brake, the suspended load could be lifted without falling.

In detail, if a suspended load is suspended in the air using only the hydraulic actuator of the lifting machine, it will gradually lower due to leakage, so the holding brake is activated to hold the suspended load. Since the load is supported by the holding brake, the internal pressure of the hydraulic actuator drops to atmospheric pressure, and if hoisted in this state, the holding brake opens and the hoisted load lowers only during step 1, when hydraulic pressure is generated in the hydraulic actuator. I will do it.

For this reason, a method of delaying the release time of the holding brake is adopted, but while this requires a high level of driving skill, if the timing is delayed too much, the suspended load may fly out.

In order to prevent these phenomena, it has been considered to seal a constant pressure into the hydraulic actuator, but since the suspended load is not constant, the effective range is narrow and impractical.

Furthermore, as a method of adjusting the pressure sealed in the hydraulic actuator against the suspended load, there is a method in which the tension of the wire rope is fed back hydraulically or electrically using a load cell, etc., but this method is complicated and expensive, and is expensive. Depending on the model, it may not even be possible to install a feedback mechanism.

The present invention relates to a device to prevent falling of a lifting machine, which was created in view of the above-mentioned circumstances.A pilot piston is slidably disposed in a cylinder, and the movement of the pilot piston causes a poppet valve to be opened and closed by a spring. The external pilot type relief pulp is constructed so as to be able to control the pressure, and a pipe is connected to the poppet valve side opening of the external pilot type relief pulp from a pipe that sends pressure oil from a hydraulic pump to a high pressure line on the load side of the hydraulic actuator. At the same time as branching, the spring built-in space connected to the poppet valve side opening is connected to the tank, and the downstream part of the piping from the branching part is connected to the pilot piston chamber of the external pilot type relief valve. A cylinder for holding the position of a pilot piston made of external high-lot relief pulp is arranged so that its piston rod can come into contact with and separate from the outer circumference of the pilot piston, and the auxiliary pump discharge side piping and the cylinder for position holding are connected to the cylinder. A cylinder mechanism that is connected by a pilot line through a driving solenoid valve, and is configured to push or pull the piston rod of the position holding cylinder by switching the cylinder driving solenoid valve. It is.

Embodiments of the present invention will be described with reference to the drawings.

Pilot piston 11 is slidable in cylinder 11a.
b is fitted into two pilot piston chambers 11c, 11.
．． A poppet valve 118 is positioned at the lower end opening of the cylinder 11a, and a spring 11f is interposed between the poppet valve 11e and the pilot piston 11b to constitute the external pilot type relief valve 11, and the hydraulic actuator 1 and counterbalance pulp 1
0 (load side high pressure line) and hydraulic pump 13
and a check valve 14 installed in the middle to prevent backflow caused by the hydraulic actuator 1.
The downstream side of the second check valve 14 and the pilot piston chamber 11c are connected via an external pilot line 15, and the piston chamber 11. and tank 16 and piping 1
The pilot piston 11 is connected to the spring 11.7 in proportion to the pressure generated in the piston chamber 11c. Allow the sushi to slide appropriately.

Also, the upstream side of the check valve 14 of the piping 12 and the poppet valve side opening of the cylinder 1a of the external pilot type relief pulp 11 are connected via the piping 18, and the lower internal space (spring 11) in the cylinder 1a is connected. A certain space) and a tank 16 are connected via a piping 19, and the hydraulic pump 13 sends oil from the piping 18 to the lower surface of the poppet valve 11e.The poppet valve 11 is pushed up against the spring 11f, and the oil is pumped from the piping 19 into the tank 16. Make it possible to send it.

Furthermore, a cylinder 20 with a built-in spring 20a is provided to adjust the position of the pilot piston 115 of the external pilot type relief pulp 11 to the piston rod 2 in the cylinder 20.
0b, and the rond side of the cylinder 20 is connected to a solenoid valve (switching valve) 21 via a pilot line 22, and the cylinder 20 is connected to a drain pipe 23 that connects the solenoid valve 21 and the tank 16. The head side of the solenoid valve 9 is connected via a drain pipe 24, and the upstream piping 25 of the solenoid valve 9
and the solenoid valve 21 are connected via an external pilot line 26.

However, the diameter d1 of the pilot piston is made slightly smaller than the diameter d2 of the pilot piston.

In the figure, 27 is a main pump, 28 is an auxiliary pump, and 29 is a pipe.

The fall prevention device A of the present invention having the above-mentioned configuration is installed in a lifting machine as shown in FIGS. 1 and 2.

The operation will be described below.

During lifting, the solenoid valve 21 is energized and switched from the state shown in FIG. Then, the rod 20b of the cylinder 20 resists the built-in spring 20&, and the pilot piston 11b of the compressed external pilot type relief pulp 11 becomes free and can slide.

On the other hand, pressure oil is transmitted to the piston chamber 11c of the external pilot type relief pulp 11 through the external pilot line 15, and the same pressure as the load pressure of the lifting machine is applied to the piston chamber 11c. The setting is "Pressure - α".

That is, the piston chamber 11c becomes a pressure setting chamber.

In the above formula, α corresponds to the difference in area between the diameters d1 and d2.

Next, we will discuss the case where the above-mentioned lifting operation is stopped. In response to the stop signal, the solenoid valve 21 becomes de-energized and switches to the state shown in FIG. Valve 21 and drain pipe 23
The oil pressure on the cylinder 200 Rondo side decreases, and the rod 20b is extended by the action of the built-in spring 20a, and the external pilot type relief pulp 11
The pilot piston 11b is crimped and held in its position, and the solenoid valve 9 is activated as shown in FIG. 8 is applied, and the load is transferred to the holding brake 8.

That is, the holding brake 8 is applied, and the position of the pilot piston 11b is maintained by the rod 20b of the cylinder 20 without being affected by pressure changes in the piston chamber 11c of the external pilot type relief pulp 11 (changes in the internal pressure of the hydraulic actuator 1). Spring 11 based on position retention
．． Therefore, the required pressure is applied to the poppet valve 11e.

Even if the internal pressure of the hydraulic actuator 1 changes in such a state, the required pressure oil is sent to the hydraulic actuator 1 by the hydraulic pump 13 via the piping 12.The position of the pilot piston 11b is maintained by the rod 20b of the cylinder 20. When the working pressure of the hydraulic pump 13 exceeds a predetermined pressure, the pressure oil from the hydraulic pump 13 pushes up the poppet valve 118 of the external pilot type relief pulp 11 and pushes the piping 18
and 19 are in communication with each other to flow into the tank 16.

Therefore, the pressure between the hydraulic actuator 1 and the counterbalance pulp 10 is always maintained at the load pressure level.

Furthermore, when lifting a suspended load that is suspended in the air, the solenoid valve 9 is energized and the changeover from the state shown in FIG. conduct.

In this case, as described above, the pressure between the hydraulic actuator 1 and the counterbalance pulp 10 is maintained at the load pressure, so that the load can be lifted without falling.

What is shown in FIG. 3 is another embodiment of the drop-off prevention device of the present invention.

That is, a cylinder 20' without a built-in spring is used, and the head side of the cylinder 20' is connected to the solenoid valve 21 through a pilot line 22, and the rod side is connected to the tank 1 through a drain pipe 24.
6, the pilot piston 11b of the external pilot relief pulp 11 can be held in position by the rod 205', and in the same way as the one shown in FIG. It is possible to prevent it from falling off.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but may be applied to the piston chamber 11 of the external pilot type relief pulp 11, for example. It is optional to connect the head side of the cylinder 20 and the rod side of the cylinder 20' directly to the atmosphere, and it goes without saying that various changes can be made without departing from the gist of the vehicle design. .

As described above, according to the device for preventing collapse of a lifting machine of the present invention, (1) Load pressure during lifting can be directly stored without indirect feedback such as electrical signals or mechanical signals.

(2) Even when the suspended load is suspended, that is, held by the holding brake, the load pressure remains exactly the same as when it was lifted, so even if the holding brake is released, the load pressure and leakage amount can be compensated. Therefore, the suspended load can be lifted without dropping.

(3) Since the load pressure is directly fed back, it is practical and can handle any load.

(4) Since the load pressure is maintained even when braking, the start of operation is smooth and there is little impact on the suspended load.

(5) Can be easily installed on general lifting machines.

(6) The position of the pilot piston of the external high-lot relief pulp was maintained using a position holding cylinder, so if hydraulic pulp was used for the pilot check valve, etc., oil leakage or oil compressibility would be slightly affected. On the other hand, it is possible to alienate this influence and do it reliably.

(7) Since the pressure for maintaining the position of the pilot piston of the external pilot type relief pulp is taken out from the constant pressure pipe 25, the position of the pilot piston can be maintained without being affected by fluctuations in load pressure.

(8) The structure is simple and can be easily and inexpensively assembled.

Demonstrates excellent effects such as

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing the case where the falling part prevention device of the present invention is used in a conventional lifting machine, Fig. 2 is an explanatory diagram showing the configuration of the falling part prevention device of the present invention, and Fig. 3 is an explanatory diagram showing the case where the falling part prevention device of the present invention is used in a conventional lifting machine. It is an explanatory view showing a deformed part of another embodiment of the device for preventing the device from falling off. 1... Hydraulic actuator, 8... Holding brake, 9, 21... Solenoid valve, 10...
... Counter balance pulp, 11 ... External pilot type relief pulp, 11 ... Cylinder, 11b ... Pilot piston, 11
11... Pilot line d Stone chamber, 11e... Poppet valve, 12, 17
゜1B, 19, 25.29... Piping, 13, 2
7゜28...Hydraulic pump, 14...Check valve, 15゜26...External pilot line, 16...Tank, 20.20'... ...
・Cylinder, 201...Spring, 20b,
20b'... Rod, 22... Pilot line, 23, 24... Drain La1.
...Pilot piston rod Ld2...
・Poppet valve side opening diameter.

Claims (1)

[Scope of utility model registration request] A pilot piston is slidably disposed within the cylinder, and an external pilot type relief pulp is configured so that the opening/closing pressure applied to the poppet valve by a spring can be controlled by the movement of the pilot piston, and is connected to the high pressure line on the load side of the hydraulic actuator. Branching a pipe connected to the poppet valve side opening of the external pilot type relief pulp from the pipe for sending pressure oil from the hydraulic pump, and connecting the spring built-in space connected to the poppet valve side opening to the tank, The downstream part of the piping is connected to the pilot piston chamber of the external pilot type relief pulp, and the piston rod of the cylinder for holding the position of the pilot piston of the external pilot type IJ valve is connected to the pilot piston chamber of the external pilot type relief pulp. The auxiliary pump discharge side piping and the position holding cylinder are connected by a pilot line via a solenoid valve for driving the cylinder, and the solenoid valve for driving the cylinder is switched. 1. An apparatus for preventing falling of a lifting machine, comprising a cylinder mechanism configured to push and pull a piston rod of the position holding cylinder.