JPS5845330Y2 - Control device for drag drum in drag line - Google Patents

Description

[Detailed explanation of the invention] This invention consists of installing a drag drum and a hoisting drum on a drive shaft connected to a hydraulic motor, equipping each drum with a hydraulically operated clutch, and installing a relief valve in the main circuit of the hydraulic motor. The present invention relates to a control device for a drag drum in a drag line provided with a switch valve and a switch valve.

First, an example of this type of drag line will be explained with reference to FIGS. 1 and 2.

An upper revolving body 2 is rotatably mounted on the truck 1. A winch 3 equipped with a hoisting drum and a drag drum (to be described later) is installed on the upper revolving body 2, and a boom 4 is raised and lowered by a boom cylinder 5. installed.

A hoisting rope 8 let out from the drum is suspended from a sheave at the tip of the boom 4, and a digging packet 6 is attached to the hoisting rope 8.
is suspended.

Further, the drag glove 7 extended from the drag drum is connected to a connecting portion of the excavation packet 6.

FIG. 1 shows the state in which the excavation bucket l-6 is lifted, and FIG. 2 shows the state in which the excavation packet 6 is being towed by the drag glove 7 to excavate the ground.

Next, a conventional hydraulic system for a winch in the above-mentioned drag line will be explained with reference to FIG.

A rotating shaft 24 connected to a hydraulic motor 15 includes a driving drum 11 equipped with a clutch 9 that is engaged and disconnected via a clutch cylinder 13, and a drag drum 12 that is equipped with a clutch 10 that is engaged and disconnected via a clutch cylinder 14.
is supported.

A playing rope 8 is wrapped around the playing drum 11, and a drag glove 7 is wrapped around the drag drum 12.

The main circuit of the hydraulic motor 15 is a high-pressure hydraulic power source 18 and an oil tank 2.
5, and on the way there is a renouf valve 17 and a switching valve 1 that controls forward rotation, stop, and reverse rotation of the hydraulic motor 15.
6 is attached.

The clutch cylinders 13, 14 are connected to a low pressure oil pressure source 19 and an oil tank 25 via clutch actuation valves 20, 21, respectively.

By switching the switching valve 16 from the illustrated neutral position to the operating position, the hydraulic motor 15 is driven, and by engaging the clutch 9 or 10 via the clutch operating valve 20 or 21, the hoisting drum 11 or the drag drum 12 is activated.
It can be rotated.

Sojo drum 11. The rope pulling force by the drag drum 12 is determined by the driving torque of the hydraulic motor 15, and
, 10 is set larger than its driving torque in consideration of the safety factor.

The driving torque of the hydraulic motor 15 is determined by the set pressure of the relief valve 17 when the switching valve 16 is switched to the a position.

In the drag line configured as described above, in order to compensate for the lack of rope traction force by the drum 12, the torque of the drums 11 and 12 must be increased, so that the boom 4,
It is necessary to increase the strength of track 1 etc.
This results in an increase in weight.

However, especially with mud excavators that work in muddy wetlands,
Weight increase is undesirable.

The object of this invention is to provide a drag line that can easily increase the torque of a drag drum without increasing the strength of the truck, boom, boom cylinder, etc.

The drag drum control device of this invention has a drag drum hoisting drum installed on a drive shaft connected to a hydraulic motor,
In a drag line in which each drum is equipped with a hydraulically operated clutch, and the main circuit of the hydraulic motor is provided with a relief valve and a switching valve, a set pressure is applied to the main circuit between the switching valve and the hydraulic motor, and the set pressure is applied to the relief valve. A safety valve is provided, and when the drag drum clutch is not operated, the pressure of the main circuit is guided to the operating pilot part of the safety valve, and when the drag drum clutch is operated, the pressure is switched by the clutch operating pressure. The present invention is characterized in that a pilot switching valve is provided to cut off the pressure of the main circuit to the operating pilot section of the safety valve.

Hereinafter, one embodiment of this invention will be explained with reference to FIG.

In this figure, the same reference numerals as in FIG. 3 represent the same things.

A safety valve 22 with a set pressure P2 smaller than the set pressure P1 of the relief valve 17 is provided in the main circuit between the switching valve 16 and the hydraulic motor 15, and the pilot circuit of the safety valve 22 includes a clutch actuation valve 21 and A pilot switching valve 23 connected to the circuit between the clutch cylinder 14 and the clutch cylinder 14 is inserted.

Other features are the same as those in Figure 3.

When the clutch operating valve 21 is not operated, the pilot switching valve 23 is in the illustrated state, that is, in the b position.

Therefore, if the switching valve 16 is switched to the a position, the driving pressure of the hydraulic motor 15 becomes the set pressure P2 of the safety valve 22.

When the clutch operating valve 21 is operated, the pilot switching valve 23 is switched to the a position by the set pressure P3, and the safety valve 220 function is stopped.

That is, the driving oil pressure of the hydraulic motor 15 becomes the set pressure P1 of the relief valve 17, which is higher than the set pressure P2 of the safety valve 22.

Therefore, the torque of the drag drum 12 increases.

For example, when the excavation packet 6 has finished cutting the ground and has been pulled sufficiently close to the truck, when the hoisting rope 8 is used to hoist the excavation bucket l-6, the clutch operating valve 20 is operated. , the switching valve 23 is not operated, and the driving pressure of the hydraulic motor 15 is the set pressure P2 of the safety valve 22.
be held down by

According to the invention described above, the torque of the drag drum during excavation of the excavation packet can be automatically increased to improve excavation performance without increasing the strength of the truck, boom, boom cylinder, etc.

[Brief explanation of the drawing]

Figure 1 is a side view of the dragline with the excavation packet hoisted up, Figure 2 is a side view of the dragline with the excavation packet digging, and Figure 3 shows the winch in the conventional dragline. Figure 4 shows the hydraulic system of the winch in the drag line according to this invention. 1... Truck, 2... Upper revolving structure,
3...Winch, 6...Drilling packet, 7...Drag glove, 8...Hoisting rope, 9,10...Clutch , 11...
・Hoisting drum, 12...Drag drum, 13.
14...Clutch cylinder, 15...
Hydraulic motor, 16...Switching valve, 17...
・Rinofu valve, 18...High pressure hydraulic power source, 19...
...Low pressure hydraulic power source, 20.21...Clutch operating valve, 22...Safety valve, 23...Pilot switching valve, 24...Rotating shaft .

Claims (1)

[Scope of utility model registration request] In a drag line in which a drag drum and a hoisting drum are installed on a drive shaft connected to a hydraulic motor, each drum is equipped with a hydraulically operated clutch, and a noleaf valve and a switching valve are installed in the main circuit of the hydraulic motor, A safety valve whose set pressure is lower than the set pressure of the IJ-F valve is provided in the main circuit between the switching valve and the hydraulic motor, and when the drag drum clutch is not operated, the operation pilot section of the safety valve is A drag drum characterized in that it is provided with a pilot switching valve that guides the pressure of the main circuit and, when the clutch of the drag drum is operated, is switched by the clutch operation pressure to cut off the pressure of the main circuit to the operation pilot section of the safety valve. control device.