JPH0520777Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to the improvement of a lift truck that carries out moving cargo, etc., to and from the upper floors of a high-rise building. This invention relates to a winch hydraulic circuit for a lift vehicle that enables smooth lowering of a bucket when the undulating angle of an extending member (guide rail) is relatively small.

[Prior art]

Lift vehicles that carry out and bring in moving cargo, etc.
When lifting a bucket with cargo loaded, it is natural that the hoisting hydraulic motor is driven regardless of the inclination (up and down angle) of the guide rail, but when transporting cargo, It is also possible to lower the bucket by rotating the hydraulic motor for hoisting in the opposite direction and using a brake device in the same way as the winch device of
As shown in the hydraulic circuit in the figure, in order to safely transport cargo, a lowering hydraulic motor 20 is actually installed separately from a hoisting hydraulic motor 21.

[Problems that ideas should solve]

However, as shown in FIG. 4, the conventional winch hydraulic circuit of a lift vehicle is equipped with a hydraulic motor 21 for hoisting and a hydraulic motor 20 for lowering independently. The hydraulic circuit of the hydraulic motor 20 shares one hydraulic pump 22, and selects, that is, by switching and operating a control valve 23, the hydraulic motor 2 for hoisting.
1 and also a hydraulic motor 21 for hoisting.
When the lowering hydraulic motor 20 is in a stopped state, the lowering hydraulic motor 20 is simply configured to be driven, and no means for adjusting the hydraulic pressure of the hydraulic oil acting on the lowering hydraulic motor 20 is taken.

In other words, since only the pilot operating pressure of the counterbalance valve 24 installed in the oil feed line of the hoisting hydraulic motor 21 acts on the conventional hoisting hydraulic motor 20, for example, the inclination angle of the guide rail is In a bucket lowering operation when the bucket is small, sufficient driving pressure cannot be obtained for the lowering hydraulic motor 20. That is, there has been a problem in that the bucket cart cannot be smoothly lowered because it cannot obtain sufficient power to move the bucket cart over the joint of the guide rail.

[Purpose of the invention and means for solving the problem]

The present invention was developed in view of the above problems, and its purpose is to improve a lift vehicle for carrying in and out of moving cargo, etc., and in particular, to improve a lift vehicle for carrying in and out of moving cargo, etc. The purpose of the present invention is to provide a winch hydraulic circuit for a lift vehicle that can smoothly lower and lower a bucket when the undulation angle of the guide rail is relatively small. In a lift vehicle, a movable extending member is attached, and a bucket is provided on the extending member, which moves up and down along the extending member when a hoisting winch device and a lowering winch device are driven. A hydraulic motor to be driven is connected to a hydraulic power source so as to always operate to wind up the winding wire, and a pipe connecting the hydraulic power source and the hydraulic motor is connected to the operating force of the hydraulic motor when the winding winch device winds up the wire. a first relief valve that is set to a control pressure that causes the hoisting wire to be paid out with a constant tension against A second relief valve set to a control pressure for winding up is connected in parallel with the hydraulic motor, and the pressure in the pipeline is connected to the branch pipeline connecting the pipeline and the first relief valve.
A directional control valve is provided to selectively control the control pressure of the relief valve and the control pressure of the second relief valve.

[Function] With the above configuration, the operating pressure of the lowering hydraulic motor can be applied in multiple stages, that is, in the present invention, variable operating pressure (rotational power) in at least three stages can be applied. Even when the angle of inclination is small and the joints of the guide rails cause a considerable amount of friction on the carrier rollers, the bucket can move smoothly downward without getting caught and stopping at the joints of the guide rails. Moreover, it is possible to work safely and efficiently.

Furthermore, since the operating pressure of the hydraulic motor for hoisting down can be set to the tank pressure, it is extremely easy to pull out the sub-guide rail to the rear of the guide rail.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a winch hydraulic circuit for a lift vehicle according to the present invention will be described in detail below with reference to FIGS. 1 to 3.

In the figure, 1 is a lift vehicle equipped with a winch device 2 that employs the lift vehicle winch hydraulic circuit according to the present invention, 3 is a turntable, and 4 is a guide rail (undulation,
5 is a sub-guide rail that can be pulled out behind the guide rail 4; 6 is along both the guide rails 4 and 5 and is raised and lowered by the winch device 2; 7 is the carrier, 8 is the undulating cylinder, and 9 is the outrigger.

By the way, the winch device 2 is shown in FIG.
As shown in b and c, there is a winch 2a on the hoisting side and a winch 2b on the hoisting side, and both winches 2a and 2b are installed on the lower surface of the guide rail 4 near the turntable 3. 10a is a hoisting wire, 10b is a hoisting wire, one end of these wires 10a and 10b is connected to the carrier 7, and the other end is connected to both winches 2a, 2b.
connected to and wound around. (See Figure 2 a, b).

11 is a hydraulic motor for hoisting, 12 is a hydraulic motor for lowering, and each of these hydraulic motors 1
1 and 12 are incorporated in both winches 2a and 2b.

Hereinafter, the hydraulic circuit of the winch device 2 will be explained based on FIG. 3.

The hoisting hydraulic motor 11 uses a first hydraulic pump 13 as a driving source, and has a loop-shaped oil supply pipe 1.
Winding up rotation and winding down rotation are also performed by switching operation of a switching valve 15 interposed in 4.

On the other hand, the oil feed pipe line 16 of the hydraulic motor 12 for hoisting is driven by a second hydraulic pump 17 installed separately from the first hydraulic pump 13, and relief valves 18 ( A first relief valve) and a relief valve 19 (second relief valve) (the set pressure of the relief valve 18 is larger than the set pressure of the relief valve 19) are installed in parallel, and the hydraulic motor 12 and one of the relief valves are installed in parallel. It is constructed as a unique loop-shaped hydraulic conduit for lowering the carrier 7, with a directional control valve 20 that can be switched in three stages interposed between the carrier 7 and the carrier 7.

In the figure, 21 is a valve unit for extending the outrigger 9, 22 is a main operation valve unit including the switching valve 15, 23 is a telescopic cylinder, and 24
is a swing motor.

The operation of the winch hydraulic circuit for a lift vehicle according to the present invention will be explained below based on the above configuration.

That is, the winch hydraulic circuit of the lift vehicle according to the present invention includes a hydraulic motor 12 for lowering the carrier 7.
In contrast, a configuration is adopted in which a second hydraulic pump 17 is installed separately from the first hydraulic pump 13 which is the drive source of the hydraulic motor 11 for hoisting, and different set pressures are used before and after the hydraulic motor 12. Relief valves 18 and 19 are interposed in parallel, and there are three stages between the hydraulic motor 12 and one of the relief valves 19, namely, a port A for supplying a predetermined amount of oil to the relief valve 19; Port B and relief valve 19 to stop oil supply
Since the directional control valve 20 is provided with a port C that stops oil supply to both the hydraulic motor 12 and the hydraulic motor 12, the operating pressure of the hydraulic motor 12 can be controlled by, for example, the directional control valve when lowering the carrier 7. 20 to a predetermined port, that is, port A (oil supply pipe 1
6 is maintained within the set pressure range of the relief valve 19, and the hydraulic motor 12 rotates with small power), port B (the operating pressure of the oil feed line 16 is maintained within the set pressure range of the relief valve 18 only). (The hydraulic motor 12 rotates with a large power because of the oil supply line 16) or port C (The hydraulic motor 12 is placed in a state where it does not rotate because the oil pressure in the oil feed line 16 drops to the reservoir tank pressure.) 7, it is possible to lower the guide rail 4 by applying a lowering speed or power corresponding to the inclination angle of the guide rail 4 or the load.

Therefore, the inclination angle of the guide rail 4 is small,
Even if a considerable amount of friction occurs on the rollers of the carrier 7 at the joints of the guide rails 4, the bucket 6 will be able to move downward smoothly without getting caught and stopping at the joints, resulting in safety. You can work efficiently.

In particular, by setting the port of the directional control valve 20 to position C, the hydraulic motor 12 is placed in a free rotating state, making it extremely easy to pull out the sub-guide rail 5 behind the guide rail 4. . In addition, since the second hydraulic pump 17 is provided for the first hydraulic pump 13, the second hydraulic motor 12 can be set in a free state even in the hoisting state, so that the wire 1, which tends to become loose, can be removed.
Since the wire 0a can also apply an appropriate tension, there will be no accidents caused by entanglement of the wire 10a.

[Effect of idea]

As explained in detail above, the present invention includes an extending member that is capable of raising and lowering, extending and contracting, and rotating freely mounted on a movable chassis, and a hoisting winch device and a lowering winch device being driven on the extending member. In a lift vehicle equipped with a bucket that moves up and down along a first relief valve set to a control pressure such that the hoisting wire is let out with a constant tension against the operating force of the hydraulic motor during hoisting by the hoisting winch device;
A second relief valve is connected in parallel with the hydraulic motor, and the control pressure set by the relief valve is large and the control pressure is set to wind up the hoisting wire when the hoisting winch device is paid out. A directional control valve that selectively controls the pressure in the pipe to the control pressure of the first relief valve and the control pressure of the second relief valve is installed in the branch pipe connecting the first relief valve, so that the lowering Since it is possible to apply variable operating pressure (rotational power) in multiple stages, that is, in the present invention, at least three stages of variable operating pressure (rotational power) on the hydraulic motor for the Even when a considerable amount of friction occurs on the rollers, the bucket can move smoothly downward without getting caught and stopping at the relevant part, and moreover, work can be done safely and efficiently. Furthermore, since the operating pressure of the hydraulic motor for hoisting down can be set to the tank pressure, it has various excellent effects such as extremely easy work when pulling out the sub-guide rail to the rear of the guide rail.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a lift vehicle equipped with a lift vehicle winch hydraulic circuit according to the present invention;
FIG. 3 is an explanatory diagram showing the winch hydraulic circuit, and FIG. 4 is an explanatory diagram showing the winch hydraulic circuit of a conventional lift vehicle. 1... Lift vehicle, 2... Winch device, 3...
Turntable, 4... Guide rail, 5... Sub guide rail, 6... Bucket (returnable box), 7
...Carrier, 8...Luffing cylinder, 9...Outrigger, 2a...Winch on hoisting side, 2b...
... Winch on the lowering side, 10a... Hoisting wire, 10b... Lowering wire, 11... Hydraulic motor for hoisting, 12... Hydraulic motor for lowering, 13... First hydraulic pump, 14... ...Oil feed pipe line, 15...Switching valve, 16...Oil feed pipe line, 17...Second hydraulic pump, 18, 19...
Relief valve, 20... Directional control valve, 21
... Valve unit, 22 ... Main operation valve unit, 23 ... Telescopic cylinder, 24 ... Swing motor.

Claims (1)

[Scope of utility model registration request] A lift in which an extending member that can rise and fall, expand and contract, and turn freely is attached to a movable chassis, and a bucket is provided on the extending member to move up and down along the extending member by driving a hoisting winch device and a lowering winch device. In the vehicle, a hydraulic motor that drives the lowering winch device is connected to a hydraulic power source so as to constantly wind the lowering wire, and the lowering winch is connected to a conduit connecting the hydraulic power source and the hydraulic motor. a first relief valve that is set to a control pressure that allows the unwinding wire to be unwound with a constant tension against the operating force of the hydraulic motor during winding up of the device; and a control pressure that is set by the first relief valve is high. A second relief valve set to a control pressure that winds up the hoisting wire when the hoisting winch device is paid out is connected in parallel with the hydraulic motor, and a branch conduit connecting the conduit and the first relief valve is connected in parallel with the hydraulic motor. , the pressure in the pipe line is
A winch hydraulic circuit for a lift vehicle, comprising a directional control valve that selectively controls the control pressure of a relief valve and the control pressure of a second relief valve.