JP2003276988A - Hydraulic circuit device of hydraulic cylinder for derricking gantry of construction machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform the mounting and removing works of a counterweight on/from a construction machine using a exclusive use hydraulic cylinder smoothly while a hydraulic cylinder of exclusive use for hoisting a gantry is left coupled with the gantry. <P>SOLUTION: The hydraulic circuit device of the hydraulic cylinder for hoisting the gantry of the construction machine includes coupling sensing limit switches 25a and 25b to sense the coupled condition when a second hydraulic cylinder 10 of exclusive use for mounting and removing the counterweight is coupled with the gantry 4, and when such sensing is made, a sensing signal is emitted to solenoid-operated selector valves 28a and 28b installed in the hydraulic circuit device, and the oil on the expansion side a and the oil in the contraction side b in a first hydraulic cylinder 7 are formed in the tank pressure with changing-over of the selector valves 28a and 28b. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic circuit device for a gantry hoisting hydraulic cylinder of a construction machine, and more particularly to a construction machine having an upper revolving structure mounted on a lower traveling structure so as to be rotatable. The present invention relates to a hydraulic circuit device for a gantry hoisting hydraulic cylinder of a construction machine in which a counterweight can be easily and quickly attached to and detached from a rear end of the upper revolving structure by using a gantry provided on the upper revolving structure. is there.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
As shown in FIGS. 4 to 7, the construction machine 1 of this type has an upper revolving structure 3 rotatably mounted on a lower traveling structure 2, and various working devices are attached to the upper revolving structure 3. In particular, a boom (not shown) is attached to the front part of the upper swing body 3 so as to be able to be raised and lowered, and a wire rope (not shown) for raising and lowering the boom is further provided.
And a gantry 4 whose lower end is pivotally attached to the upper revolving structure 3 so as to be capable of undulating, and a sheave 5 is rotatably attached to an upper end of the gantry 4, and the wire rope is attached to the bridle. And around the sheave 5 via a bail, and further connected to a winch (not shown) installed on the upper swing body 3 to drive the winch to move the boom through the wire rope. It is formed so that it can be undulated.

Thus, the gantry 4 is composed of an upper pastort 4a and a mast 4b.
And the mast 4b are each formed in a gate shape. That is, the lower ends of the two Appas struts 4a and the mast 4b face each other left and right (front and rear in FIG. 4) and are pivotally attached to the upper revolving structure 3,
The upper ends of the sheaves 5 are abutted against each other and connected by a shaft 6, and the sheave 5 is pivotally attached to the shaft 6, and further between the lower part of the upper pastort 4a and the rear part of the upper swing body 3. A first hydraulic cylinder 7 for ups and downs of the up-paste struts 4a is connected to the upper part of the upper struts 4a, and in the normal case, as shown in FIGS.
The gantry 4 constituted by a and the mast 4b is configured so that it can be freely raised and lowered by the expansion and contraction action of the first hydraulic cylinder 7. At this time, the second hydraulic cylinder 10 described later is not connected to the gantry 4.

Thus, in this type of construction machine 1, the weight of the construction machine 1 is balanced by attaching a counterweight having a weight suitable for the working device to the rear end of the upper swing body 3. The upper revolving structure is formed so that the revolving structure and various operations can be smoothly performed.

Therefore, as shown in FIGS. 6 and 7, the gantry 4 is used to suspend the counterweight 8 by a suspension wire 9, and the counterweight 8 is attached to the rear end portion of the upper swing body 3. When performing the attachment / detachment operation to / from the
The hydraulic cylinders 10 are connected, and the gantry 4 is undulated by the expansion and contraction of the second hydraulic cylinders 10 to attach or detach the counterweight 4 to or from the upper swing body 3. At this time, the connection between the first hydraulic cylinder 7 and the gantry 4 is released. If the second hydraulic cylinder 10 is driven while the first hydraulic cylinder 7 is connected to the gantry 4, the oil in the first hydraulic cylinder 7 acts as a reaction force to operate the second hydraulic cylinder 10. It will cause problems. Therefore, conventionally, when the counterweight 8 is attached to and detached from the upper swing body using the gantry 4,
The connection pin (not shown) of the hydraulic cylinder 7 to the gantry 4 is pulled out to release the connection between the first hydraulic cylinder 7 and the gantry 4.

Therefore, the working time is shortened by omitting the work of detaching the connecting pin of the first hydraulic cylinder 7.
In addition, a technical problem to be solved in order to prevent damage to the first hydraulic cylinder and the gantry arises, and the present invention aims to solve the problem.

[0007]

DISCLOSURE OF THE INVENTION The present invention has been proposed in order to achieve the above-mentioned object, and an upper revolving structure is mounted on a lower traveling structure, and a gantry is pivotally attached to the upper revolving structure so that the gantry can be raised and lowered. Then, a first hydraulic cylinder dedicated to undulating the gantry is connected between the gantry and the upper revolving structure, a second hydraulic cylinder dedicated to hanging the counterweight is connected when the counterweight is suspended, and the first hydraulic pressure is In a hydraulic circuit device for a gantry undulating hydraulic cylinder, wherein the cylinder and the second hydraulic cylinder are formed so as to expand and contract by switching respective directional control valves. In the hydraulic circuit device, the second hydraulic cylinder is connected to the gantry. When connected, a connection detector for detecting the connection state is provided, and when the connection state of the second hydraulic cylinder is detected by the connection detector,
The detection signal is output to an electromagnetic switching valve provided in the hydraulic circuit device, and the expansion side oil and the contraction side oil in the first hydraulic cylinder are formed into tank pressure by switching the electromagnetic switching valve. A hydraulic circuit device for a gantry hoisting hydraulic cylinder of a construction machine, and the connection detector are composed of a limit switch. When the limit switch is turned on, a detection signal of the limit switch is output by switching a relay. And a hydraulic circuit device for a gantry hoisting hydraulic cylinder of a construction machine configured to stop the operation of the directional control valve of the first hydraulic cylinder.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described in detail below with reference to FIGS. For convenience of description, the same components as those of the conventional example will be denoted by the same reference numerals and the description thereof will be omitted.

FIGS. 1 and 2 correspond to FIGS. 6 and 7 of the conventional example, but in the present invention, when the counterweight 8 is attached to and detached from the upper swing body 3 by using the gantry 4. , The first hydraulic cylinder 7 is connected to the gantry 4, and the counterweight 8 can be attached to or removed from the rear end of the upper swing body 3 only by the expansion and contraction of the second hydraulic cylinder 10. Is there.
The first hydraulic cylinders 7 are attached to the respective sides of the portal gantry 4 (front and rear in FIGS. 1 and 2).

Next, the operation of the first hydraulic cylinder 7 dedicated to the ups and downs of the gantry 4 will be described with reference to FIG. 1 in the figure
Reference numeral 1 denotes a tank, and the tank 11 has a main pump 13 and a pilot pump 1 which are operated by driving an engine 12.
4 is connected, and the pressure oil discharged from the main pump 13 is connected to the direction control valve 16 via the main oil passage 15. The directional control valve 16 is formed at the 6-port 3-position, the central position (a) is the neutral position, and the left position (b) is the switching position of the first hydraulic cylinders 7, 7 to the extension side,
The position (c) on the right side is the switching position of the first hydraulic cylinders 7, 7 to the reduction side.

FIG. 3 shows a state in which the directional control valve 16 is in the neutral position and the first hydraulic cylinders 7, 7 are not operating. The pilot oil discharged from the pilot pump 14 is connected via a pilot oil passage 17 to solenoid valves 18, 18 arranged on the left and right of the directional control valve 16, and the solenoid valves 18, 18 are respectively connected to the signal lines 20a and 20b arranged between the extension side and the contraction side of the gantry raising / lowering switch 19, and the gantry raising / lowering switch 19 is connected to the extension side (X) or the contraction side ( When any one of Y) is turned on, any one of the solenoid valves 18 corresponding to the above is switched by inputting an ON signal from the gantry lifting switch 19, and the pilot oil from the pilot oil passage 17 is changed. One of the left and right spools 21 of the directional control valve 16 is slid to slide the directional control valve 1
6 of the left and right positions (b) and (c) to switch the pressure oil from the main oil passage 15 to the outlet oil passage 22a,
22b of the first hydraulic cylinder 7, 7 via the outlet side oil passage 22a or 22b corresponding to the position (b) or (c) at which the directional control valve 16 is switched, respectively. The first hydraulic cylinders 7, 7 are press-fitted into one of the sides b, b so that the first hydraulic cylinders 7, 7 can expand and contract, and the gantry 4 can be undulated.

In FIG. 3, reference numeral 23 is a check valve and 24 is a relief valve. The above is gantry 4
The hydraulic circuit for generally hoisting the gantry 4 by the dedicated first hydraulic cylinders 7, 7 connected to the above has been described. The gantry 4 is used to move the counterweight 8 to the rear end portion of the upper swing body 3. When attaching and detaching, the second hydraulic cylinders 10, 10 are separately provided without using the first hydraulic cylinders 7, 7 so as to face each other between the rear end portion of the upper swing body 3 and the vicinity of the upper end portion of the gantry 4. Interlocking, and
The gantry 4 is undulated by the expansion and contraction operation of the second hydraulic cylinders 10, 10 to attach and detach the counterweight 8 suspended from the suspension wire 9 to the upper swing body 3. At this time, the connection between the first hydraulic cylinders 7 and 7 and the gantry 4 is not released.

Therefore, the left and right second hydraulic cylinders 1
When 0 and 10 are respectively connected to the gantry 4, as shown in FIG. 3, the left connection detection limit switch 25a and the right connection detection limit switch 2 for detecting the connection state.
5b respectively, and when the left and right connection detection limit switches 25a and 25b are turned on, the relay 26
By switching the left and right connection detection limit switches 2
The detection signals of 5a and 25b are output to the left and right electromagnetic switching valves 28a and 28b via the signal line 27. The electromagnetic switching valve 2
8a and 28b are normally closed type, each of which is formed at 4 port 2 position, and in the figure, the upper part is formed at the communicating position (d) and the lower part is formed at the blocking position (e). Therefore, when the left and right connection detection limit switches 25a and 25b are off, the electromagnetic switching valves 28a and 28b are in the shut-off position (e).
It is in.

When the detection signal is input to the electromagnetic switching valves 28a and 28b, the gantry raising / lowering switch 19 is turned off, so that the directional control valve 16 maintains the neutral position (a). Does not work. Further, since oil still remains on the extending sides a, a and the contracting sides b, b in the left and right first hydraulic cylinders 7, 7, this oil acts as a reaction force of the operation of the second hydraulic cylinders 10, 10. Therefore, the functions of the second hydraulic cylinders 10, 10 are diminished.

Therefore, the expansion sides a and a of the first hydraulic cylinders 7 and 7 and the contraction sides b and b of the first hydraulic cylinders 7 and 7 are connected by oil passages 29a and 29b, respectively, and the expansion sides a and a are connected.
The oil passage 29a of the solenoid valve 28a of FIG.
, And the oil passages 29b on the reduction sides b, b are connected to the lower electromagnetic switching valve 28b. Further, the electromagnetic switching valves 28a and 28b are connected to oil passages 30 connected to the tank 11, respectively.

Thus, the left and right second hydraulic cylinders 10,
When 10 is connected, the left and right connection detection limit switches 25a, 25b are respectively turned on, and the detection signal of the connection detection limit switches 25a, 25b is switched via the signal line 27 by switching the relay 26. The electromagnetic switching valves 28a and 28b are switched to the communicating position (d) (d). In that case, the oil in the extension sides a of the first hydraulic cylinders 7, 7 is allowed to flow through the oil passage 29a to the electromagnetic switching valve 28.
It passes through the communication position (d) of a and is communicated with the tank 11 via the oil passage 30 connected to the tank 11. Further, the oil in the reduction side b of the first hydraulic cylinder 7, 7 passes through the oil passage 29b, the communication position (d) of the lower electromagnetic switching valve 28b, and the oil passage 30 to the tank 1
It is connected to 1. Therefore, the oil in the first hydraulic cylinders 7, 7 becomes tank pressure on both the expansion side a, a and the contraction side b, b, and there is no hindrance to the operation of the second hydraulic cylinders 10, 10. There is nothing to do. Therefore, when the second hydraulic cylinders 10, 10 are connected to the gantry 4, and the counterweight 8 is attached to and detached from the upper swing body 3 by the second hydraulic cylinders 10, 10, the first hydraulic cylinders 7, 7 are connected to the gantry 4. Even in the state of being connected to 4, the counterweight 8
The attachment / detachment work will be smoothly performed.

The present invention can be modified in various ways without departing from the spirit of the present invention, and it goes without saying that the present invention extends to such modifications.

[0018]

As described in detail in the above-mentioned one embodiment, when the counterweight is attached to and detached from the upper swing body by the second hydraulic cylinder, the connection of the second hydraulic cylinder to the gantry is the connection detector. Is detected by the switch, and this detection signal is output to the electromagnetic switching valve by switching the relay. In that case, the electromagnetic switching valve switches to the communication position to communicate the oil in the first hydraulic cylinder to the tank. Therefore, the first hydraulic cylinder has the tank pressure. Thus, when the counterweight is attached / detached by the second hydraulic cylinder, the first hydraulic cylinder does not hinder the operation of the second hydraulic cylinder even when the first hydraulic cylinder is connected to the gantry. The operation of attaching and detaching the counterweight by the second hydraulic cylinder is smoothly performed. Therefore, unlike the prior art, it is possible to save the labor for attaching and detaching the connecting pin of the first hydraulic cylinder, shorten the attaching and detaching work time of the counterweight, and prevent the first hydraulic cylinder and the gantry from being damaged. It is an invention that has a truly remarkable effect.

[Brief description of drawings]

FIG. 1 is an explanatory side view showing an embodiment of the present invention when a counterweight is lifted.

FIG. 2 is an explanatory side view showing a state in which the counterweight is suspended from the state shown in FIG.

FIG. 3 is a hydraulic circuit diagram showing an embodiment of the present invention.

FIG. 4 is an explanatory side view showing a state where the gantry is raised by a first hydraulic cylinder dedicated to the gantry.

5 is an explanatory side view showing a state in which the gantry is tilted from the state shown in FIG.

FIG. 6 is an explanatory side view showing a conventional example in which the counterweight is being lifted by a second hydraulic cylinder.

7 is an explanatory side view showing a state in which the counterweight is suspended from the state shown in FIG.

[Explanation of symbols]

1 construction machinery 2 Undercarriage 3 Upper revolving structure 4 gantry 7 First hydraulic cylinder 8 counterweight 10 Second hydraulic cylinder 11 tanks 16 directional control valve 25a, 25b Connection limit switch 26 relays 27 signal line 28a, 28b Solenoid switching valve a Extension side of the first hydraulic cylinder b Reduction side of first hydraulic cylinder

Claims (2)

[Claims] 1. A first hydraulic cylinder dedicated to undulating a gantry, wherein an upper revolving structure is mounted on a lower traveling structure, and a gantry is pivotally attached to the upper revolving structure so as to be capable of undulating. When the counterweight is suspended, the second hydraulic cylinder dedicated to suspending the counterweight is coupled,
In addition, in the hydraulic circuit device of the gantry raising and lowering hydraulic cylinder, wherein the first hydraulic cylinder and the second hydraulic cylinder are formed to be expandable and contractable by switching the respective directional control valves, the hydraulic circuit device includes the second hydraulic cylinder. When the hydraulic cylinder is connected to the gantry, a connection detector is provided to detect the connection state, and when the connection detector detects the connection state of the second hydraulic cylinder, the detection signal indicates the hydraulic pressure. The construction is characterized in that the oil is output to an electromagnetic switching valve provided in the circuit device, and the expansion side oil and the contraction side oil in the first hydraulic cylinder are formed at the tank pressure by switching of the electromagnetic switching valve. Hydraulic circuit device for hydraulic cylinders for undulating machinery gantry. 2. The connection detector comprises a limit switch, and when the limit switch is turned on, a detection signal of the limit switch is output to the solenoid operated directional control valve by switching a relay and a direction of the first hydraulic cylinder. The hydraulic circuit device for a gantry hoisting hydraulic cylinder of a construction machine according to claim 1, wherein the hydraulic circuit device is configured to stop the operation of the control valve.