JPH07228485A - Expansion/shrinkage detecting device for travel body in construction machine - Google Patents

Abstract

PURPOSE:To provide an expansion/shrinkage detecting device for a travel body capable of using a small and inexpensive hydraulic rotary joint in a construction machine provided with the travel body having a structure with a variable width between crawler belts or the travel body having outriggers with variable interval between them. CONSTITUTION:A travel body 1 is provided with a hydraulic selector valve 14 switched by the expansion/shrinkage of crawler belts 9 or outriggers. A hydraulic source on a revolving superstructure 3 and the hydraulic selector valve 14 are connected via a hydraulic rotary joint 18. A pressure sensor detecting the change in the oil pressure due to the switching of the hydraulic selector valve 14 is provided on the revolving superstructure 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling body or an outrigger for a construction machine such as a hydraulic excavator, a crawler crane, a pile driver, an excavator, etc. It relates to a stretch detection device.

[0002]

2. Description of the Related Art Some construction machines having a crawler type traveling body such as a hydraulic excavator have a structure in which a width between crawler tracks of the traveling body can be changed in order to make the transportation system compact. Further, an outrigger mounted on a construction machine having a wheel-type traveling body such as a truck crane generally has a structure in which the distance between the left and right outriggers can be changed so that the outrigger can be projected outward during work.

FIG. 5A is a side view showing a conventional crawler crane having a structure in which the width between crawler belts can be changed, and FIG. 5B is a sectional view taken along line EE of FIG. As shown in FIG. 5, in the crawler crane, a revolving structure 3 is installed on a traveling structure 1 via a revolving device 2, and the revolving boom 4 is mounted on the revolving structure 3.
Be installed. The traveling body 1 includes a track frame 5 on which the turning device 2 is installed, a side frame 6, and a crawler belt 9 wound around a drive wheel 7 attached to one end of the side frame 6 and a driven wheel 8 attached to the other end. Become.
The side frame 6 is provided with guide holes 6a in the front and rear thereof,
Beams 5a provided so as to project to the left and right of the track frame 5 are slidably fitted in these guide holes 6a.

As shown in FIG. 5B, when the crawler crane is mounted on a trailer or the like and transported to the site, a hydraulic cylinder (not shown) for expansion and contraction provided between the left and right side frames 6, 6 is used. By contracting, the track 9 is
It is reduced from the center of turning of the turning device 2 so that the protruding width becomes a small width indicated by a. On the other hand, when performing a crane operation, the hydraulic cylinder is extended to increase the stability during the operation so that the projecting width of the crawler belt 9 from the turning center of the turning device 2 is enlarged as shown in b. In such a crawler crane, if the work of widening the space between the crawler tracks 9 is forgotten or the work is started in a state where the widening is insufficient, the crawler crane may fall. Further, even in a construction machine such as a truck crane in which traveling bodies are equipped with outriggers that can be expanded and contracted from each other, there is a risk of forgetting the work to widen the outriggers or starting work in a state where the widening is insufficient.

Therefore, in such a crawler crane, as shown in an enlarged view of FIG. 6 (A), a micro switch 10 which operates when the crawler belt 9 is in a narrowed state is provided on the beam 5a of the track frame 5. When the crawler belt 9 is in the reduced width state, the micro switch 10 is activated to activate an alarm device such as a lamp, a sound or a sound generator, or the undulation of the boom 4 and the swing of the swing body 2 are automatically stopped. Is configured as follows. Further, also in a construction machine in which a traveling body is equipped with an expandable / contractible outrigger, a micro switch 10 that operates when the outrigger is in a contracted state is also provided.

[0006]

However, according to this conventional structure, the hydraulic rotary joint 12 attached to the swivel device 2 is used.
Is required to connect the traveling drive hydraulic system of the revolving structure 3 and the traveling structure 1 and also to connect the electric wiring for transmitting the electric signal from the micro switch 10. Therefore, as shown in FIG. The general hydraulic rotary joint 11 as shown in FIG. 6 (B) cannot be used, and a special hydraulic rotary joint 12 as shown in FIG. 6 (C) capable of connecting the hydraulic circuit and the electric circuit is required.

Here, the joints 11 and 12 will be described. In FIG. 6B, 11a is a running body 1.
A spindle member 11b fixed to the side, a casing member 11b rotatably fitted to the spindle member 11a and fixedly provided on the revolving unit 3 side, and 11c and 11d respectively attached to these members 11a and 11b. Each of the oil passages provided and connected to each other through the annular groove 11e is shown. Figure 6
The hydraulic rotary joint 12 shown in (C) has a through hole 1 for electrical wiring vertically at the center of the spindle member 12a on the traveling body 1 side.
2f is provided and slip ring 1 for electrical wiring connection is provided on the upper part
It has a structure in which 3 is added. The slip ring 13 includes a shaft member 13a fixed to a spindle member 12a on the traveling body 1 side and a casing member 12b on the revolving body side.
The female member 13b fixed to the above is rotatably fitted in a state of being electrically contacted by a ring and a brush. Note that 12c and 12d are oil passages, and 12e is an annular groove. Since the hydraulic rotary joint 12 has a structure capable of connecting the hydraulic circuit and the electric circuit in this manner, the general hydraulic rotary joint 11
There is a problem in that the structure is complicated, the size is large, and the cost is high as compared with the above.

In view of the above problems, the present invention provides a construction machine having a traveling body having a structure in which the width between the crawler belts can be changed and a traveling body equipped with outriggers whose mutual intervals can be expanded and contracted. It is an object of the present invention to provide an extension / contraction detection device for a traveling body that can use a low-priced hydraulic rotary joint.

[0009]

In order to achieve the above-mentioned object, the present invention provides a traveling body in which the distance between the left and right crawler belts or the distance between outriggers can be expanded and contracted, and is installed on the traveling body via a turning device. In a construction machine having a revolving superstructure, a hydraulic power source mounted on the revolving superstructure, and a hydraulic rotary joint connecting the hydraulic power source and the traveling body driving hydraulic system to the revolving device,
The traveling body is provided with a hydraulic pressure switching valve that is switched by expansion and contraction of a crawler track or an outrigger, and a hydraulic pressure source on the swinging body and the hydraulic pressure switching valve are connected via the hydraulic rotary joint, and the hydraulic pressure switching is performed on the swinging body. It is characterized in that a pressure sensor for detecting a change in hydraulic pressure due to valve switching is provided.

[0010]

According to the present invention, the hydraulic switching valve is switched between a state where the crawler belt of the traveling body is narrowed or a space between the outriggers is expanded, whereby the hydraulic switching valve and the hydraulic source are connected. The hydraulic pressure of the pipeline changes, and the change in hydraulic pressure is transmitted to the pressure sensor provided on the revolving structure via the hydraulic rotary joint, whereby the expansion / contraction of the crawler belt or the outrigger can be known. Therefore, it is not necessary to provide the hydraulic rotary joint with an electric signal transmission device for transmitting the narrowed state between the crawler belts.

[0011]

1 is a sectional view showing a traveling body of a crawler crane equipped with an embodiment of a traveling body expansion / contraction detecting device according to the present invention, and FIG. 2 (A) is a hydraulic circuit diagram thereof. In FIG. 1, the same reference numerals as those in FIG. 6A indicate parts or portions having an equivalent function, and the traveling body 1 of the present crawler crane has a hydraulic switching valve 14 on the beam 5a of the rear track frame 5.
The hydraulic switching valve 14 is configured such that when the crawler belt 9 is contracted, the operating body 14a of the hydraulic switching valve 14, such as a rod or a lever, is pushed by the side frame 6 to switch. In FIG. 2A, reference numeral 15 is a hydraulic source including a hydraulic pump mounted on the revolving structure 3, and 33.
Is a pipeline connected to the hydraulic power source on the revolving structure 3 and the traveling motor of the traveling body 1 and the crawler track expansion / contraction hydraulic cylinder. In the present embodiment, the hydraulic pressure source 15 is connected to the drain pipeline 32 via the hydraulic rotary joint 18. The discharge circuit of the throttle 17, the conduit 16 on the revolving structure, the hydraulic rotary joint 18, the conduit 31a on the traveling structure,
31b and the hydraulic switching valve 14 are connected. 1
Reference numeral 9 denotes a pressure sensor connected to the pipe 16 on the revolving structure 3. The pressure sensor 19 detects a change in the pressure of the pipe 16, and when the pressure exceeds a set value, a safety device 20 is provided.
Or and and is configured to send a signal to the moment limiter 21.

The safety device 20 is provided with an alarm device such as a sound or sound generator or a lamp which operates in response to a signal from the pressure sensor 19 or the boom 4, the revolving structure 3, and a hoisting winch (not shown). ) Etc., such as an auto-stop device that forcibly switches the control valve of the crane actuator to the stop position and stops. The moment limiter 21 receives a signal from the pressure sensor 19,
The lifting capacity of the crane is switched to a lower characteristic (the characteristic of the lower curve b among the curves of a and b in the relationship diagram of the lifting load W and the working radius R).

Next, the operation of the hydraulic circuit shown in FIG. 2A will be described. The hydraulic pressure switching valve 14 is located at the left position in the figure when the crawler belt 9 is widened, and the pressure sensor 19 is provided.
A low hydraulic pressure substantially equal to the tank pressure reduced by the action of the throttle 17 is applied to. Then, when the crawler belt 9 is narrowed, the hydraulic pressure switching valve 14 is switched to the right position, the pressure oil from the hydraulic pressure source 15 is cut off by the hydraulic pressure switching valve 14, and the hydraulic pressure in the pipeline 16 is changed to the hydraulic pressure source 15. Equal to the hydraulic pressure of. As a result, the pressure sensor 19 emits a signal to activate the safety device 20 and / or the moment limiter 21. Therefore, the operator receives an alarm with the alarm,
An operator performs an operation such as widening the crawler belt 9 or switches the mode to a mode in which the characteristic of the crane is limited to a small load by the moment limiter 21. Occurrence of an accident can be prevented.

As described above, when the width between the crawler belts 9 of the traveling body 1 is kept in the narrowed state, the hydraulic pressure of the pipe line 16 becomes high, and the revolving structure is provided via the hydraulic rotary joint 18 provided in the revolving device 2. Since the pressure sensor 19 provided on the 3 detects the hydraulic pressure and operates, unlike the case where the conventional micro switch 10 is used, the reduced width state of the track 9 is transmitted to the revolving structure 3 without using an electric signal. You can Therefore, the hydraulic rotary joint 18
Since only the hydraulic circuit is connected and it is not necessary to provide an electric signal transmission mechanism such as a slip ring, a small-sized and inexpensive hydraulic rotary joint that constitutes the expansion / contraction detection device of the traveling body can be used. As the hydraulic pressure switching valve 14, contrary to the case of FIG. 2 (A), it is also possible to use a valve that shuts off the pipelines 31a and 31b in the narrowed state and connects the pipelines 31a and 31b in the widened state. Good.

FIG. 2B is a hydraulic circuit diagram of another embodiment of the extension / contraction detecting device for a traveling body according to the present invention. In the hydraulic circuit of this example, instead of the hydraulic pressure switching valve 14 of FIG. 2 (A), the hydraulic pressure switching valve 22 provided on the traveling body side is used as one of the secondary side pipelines 31b.
Is connected to the drain system conduit 32, and the other traveling body side secondary conduit 31c is connected to the pressure sensor 19 via the hydraulic rotary joint 24 and the conduit 16a on the revolving structure. is there. In this example, in the widened state in which the operating body 22a is not operated by the side frame 6, the hydraulic pressure from the hydraulic pressure source 15 causes the hydraulic pressure from the hydraulic line 16, the hydraulic rotary joint 24, and the hydraulic line 3.
1a, hydraulic switching valve 22, pipeline 31c, hydraulic rotary joint 24
And the pressure sensor 19 through the pipe 16a,
On the other hand, when the operating body 22a is pushed by the track frame 6 and the hydraulic pressure switching valve 22 is switched, the pipe line 31c connected to the pressure sensor 19 communicates with the drain circuit 32 via the hydraulic pressure switching valve 22 and the pipe line 31b. The hydraulic pressure applied to the sensor 19 becomes the tank pressure, and the pressure sensor 19 detects this pressure change and operates, so that the safety device 20 or the moment limiter 21 can be operated in the same manner as described above. The effect is obtained. Further, the number of hydraulic pipes in the hydraulic rotary joint 24 is increased by one as compared with the above-mentioned embodiment, but since the hydraulic oil does not continue to flow in the pipeline 16 and the pipeline 23, the loss of power is small. It has the advantage of being completed.

FIG. 3 is a side view showing a truck crane in which another embodiment of the extension / contraction detecting device for a traveling body according to the present invention is applied to an outrigger capable of expanding / contracting mutually, and FIG. 4 is a side view of FIG.
It is a F cross-sectional view (shown in a working state). As shown in FIGS. 3 and 4, the truck crane comprises a revolving unit 3 mounted on a traveling unit 1A via a revolving device 2, and a boom 4 attached to the revolving unit 3. A drive wheel 7A is attached to a truck frame 5A on which the turning device 2 is installed. Outriggers 25 are provided on the front and rear sides of the track frame 5A, and the beams 26 are slidably fitted to the outrigger boxes 25a of these outriggers 25 so as to be projected to the left and right, respectively, so that their mutual intervals can be expanded and contracted. A float 28 that is moved up and down by a jack cylinder 27 is provided at the tip of the beam 26. During work, the space between the left and right beams 26, 26 is widened, the jack cylinder 27 is extended and the float 28 is grounded, and the track is tracked. Stabilize the crane. Reference numeral 14 (22) is a hydraulic pressure switching valve attached to the left and right of the front and rear outrigger boxes 25a, and the hydraulic pressure switching valve 14 (22) is configured to be switched when the beams 26 are stored in the outrigger box 25a. Has been done. The hydraulic pressure switching valve 14 (22)
The hydraulic circuit that connects the hydraulic power source 5 on the revolving structure 3 is configured in the same manner as the hydraulic circuit (see FIG. 2 (A) or (B)). The operation of the sensor 19 can be the same as that described above.

In this way, the reduced width state between the left and right beams 26, 26 of the outrigger 25 can be transmitted to the revolving structure 3 only by the hydraulic circuit. A compact and inexpensive hydraulic rotary joint can be used.

[0018]

According to the present invention, the traveling body is provided with a hydraulic pressure switching valve that is switched by expansion and contraction of the crawler belt or the outrigger, and the hydraulic power source on the revolving structure and the hydraulic pressure switching valve are provided via a hydraulic rotary joint provided in the revolving device. And a pressure sensor for detecting a change in hydraulic pressure due to switching of the hydraulic pressure switching valve is provided on the revolving structure, the hydraulic pressure is switched depending on whether the crawler belt or the outrigger is in a narrowed state or a widened state. By switching the valve, the hydraulic pressure of the pipe connecting the hydraulic switching valve and the hydraulic pressure source changes, and the change in hydraulic pressure is transmitted to the pressure sensor provided on the revolving structure via the hydraulic rotary joint. Therefore, unlike the case where the conventional micro switch is used, it is not necessary to provide an electric signal transmission mechanism in the hydraulic rotary joint, and a small and inexpensive hydraulic rotary joint constituting the expansion / contraction detection device of the traveling body can be used.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a traveling body of a crawler crane equipped with an embodiment of a traveling body expansion / contraction detecting device according to the present invention.

FIG. 2A is a hydraulic circuit diagram of the embodiment, and FIG. 2B is a hydraulic circuit diagram of another embodiment of the traveling body extension / contraction detection device according to the present invention.

FIG. 3 is a side view showing a truck crane having an outrigger to which the present invention is applied.

FIG. 4 is an enlarged sectional view taken along line FF of FIG. 3 showing another embodiment of the present invention.

FIG. 5A is a side view showing a conventional crawler crane having a structure in which the distance between crawler belts can be expanded and contracted, and FIG. 5B is an EE enlarged sectional view of FIG.

FIG. 6A is an enlarged sectional view showing a traveling body of a crawler crane, and FIG. 6B is a longitudinal sectional view showing a general hydraulic rotary joint.
(C) is a longitudinal sectional view showing a hydraulic rotary joint to which both a hydraulic circuit and an electric circuit can be connected.

[Explanation of symbols]

 1, 1A Traveling body 2 Revolving device 3 Revolving structure 4 Boom 5, 5A Center frame 5a, 26 Beam 6 Side frame 7, 7A Drive wheel 9 Crawler belt 11, 12, 18, 24 Hydraulic rotary joint 14, 22 Hydraulic switching valve 15 Hydraulic pressure Source 16, 16a, 31a to 31c, 33 Pipe line 17 Restrictor 19 Pressure sensor 20 Safety device 21 Moment limiter 25 Outrigger 32 Drain line

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location E02F 9/02 A

Claims (2)

[Claims] 1. A traveling body having a space between the left and right crawler belts that can be expanded and contracted, and a revolving body installed on the traveling body via a revolving device, and a hydraulic power source is mounted on the revolving body. In a construction machine having a turning device provided with a hydraulic rotary joint that connects the hydraulic source and a hydraulic system for driving a traveling body, a hydraulic switching valve that is switched by expansion and contraction of a crawler track is provided on the traveling body, and a hydraulic source on the revolving body is provided. And a hydraulic pressure switching valve connected via the hydraulic rotary joint, and a pressure sensor for detecting a change in hydraulic pressure due to switching of the hydraulic pressure switching valve is provided on the revolving structure. Stretch detection device. 2. A traveling body having an outrigger capable of expansion and contraction,
A hydraulic rotation having a revolving structure installed on the traveling structure via a revolving device, a hydraulic power source being mounted on the revolving structure, and connecting the hydraulic power source and the traveling body driving hydraulic system to the revolving device. In a construction machine provided with a joint, the traveling body is provided with a hydraulic pressure switching valve that is switched by expansion and contraction of an outrigger, and a hydraulic power source on the swinging body and the hydraulic pressure switching valve are connected via the hydraulic rotary joint, and the swinging is performed. An extension / contraction detecting device for a traveling body in a construction machine, comprising a pressure sensor for detecting a change in hydraulic pressure due to switching of the hydraulic pressure switching valve on the body.