JPH1053169A - Crawler belt expansion contraction detector for construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform a work suitable for an intermediate work by detecting a state that a distance between crawlers is situated in an intermediate position, in a crawler belt expansion contraction detecting device for a working machine. SOLUTION: Respective times when a crawler belt is situated in an expansion position, in an intermediate position, and in a contraction position are detected by pressure detectors 25, 26, and 27 connected to a hydraulic cylinder 10 to effect expansion and contraction of the crawler. The detecting results are inputted to a controller 56, and the controller 56 selects a desired rated load curve from a rated load curve stored at a moment limiter 57 and switches lifting capacity of a crane.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a crawler belt expansion / contraction detection device for a construction machine having a lower traveling body in which the crawler belt interval can be expanded or contracted, which detects the position of the crawler belt when the crawler belt expands or contracts.

[0002]

2. Description of the Related Art In crawler-type construction machines such as crawler cranes and hydraulic shovels, the crawler spacing is increased to increase the stability during work, and the crawler spacing is reduced during transportation to reduce the size of the vehicle. Is known. FIG. 2 is a side view showing a crawler crane provided with a crawler belt expanding / contracting mechanism, and FIG. 3 is a front view thereof. As shown in FIGS. 2 and 3, the crawler crane has an upper revolving unit 3 provided on a lower traveling unit 1 via a revolving wheel 2, and an up-and-down boom 4 is attached to a front portion of the upper revolving unit 3. I have. Further, a counterweight 11 for balancing the vehicle body during work is attached to a rear portion of the upper swing body 3. The undercarriage 1 is wrapped around a track frame 5 on which the turning wheel 2 is installed, a side frame 6, a driving wheel 7 attached to one end of the side frame 6, and a driven wheel 8 attached to the other end. Track 9. Guide holes 6a are formed in front and rear of the side frame 6, and the track frame 5 is slidably fitted in the guide holes 6a.

In such a crawler crane, when the crane is mounted on a trailer or the like and transported to the site, a hydraulic cylinder for expansion and contraction (not shown) provided between the left and right side frames 6 is contracted to move between the crawler tracks 9. Reduce the spacing. On the other hand, at the time of work, in order to increase the stability during the work, the hydraulic cylinder for expansion / contraction is extended to increase the interval between the crawler belts 9. In such a crawler crane, if the operation of expanding the interval between the crawler belts 9 is forgotten or the operation is performed in a state where the expansion is insufficient, the stability of the crawler crane is impaired. For this reason, it is detected that the crawler belt is in the contracted state, and when the crawler belt is in the contracted state, the rated load curve representing the relationship between the suspended load and the work radius according to the contracted state is selected, and the crane is selected. There has been proposed a crawler crane capable of performing an operation suitable for a contracted state without falling down (for example, Japanese Patent Application Laid-Open No. H7-228485).

[0004]

However, in the crawler crane described in the above-mentioned Japanese Patent Application Laid-Open No. 7-228485, the crawler belt detects that the crawler belt is in a contracted state, and selects a rated load curve according to the contraction. The crawler belt cannot detect the intermediate state between the expanded state and the contracted state, selects a rated load curve suitable for this intermediate state, and cannot perform the work corresponding to the intermediate state of the crawler belt. there were.

An object of the present invention is to provide a crawler belt stretch detection device for a construction machine which can detect a crawler belt even when the crawler belt is in an intermediate state between an expanded state and a contracted state.

[0006]

FIG. 1 shows an embodiment of the present invention.
Referring to FIG. 3, the invention according to claim 1 includes a lower traveling body 1 in which the interval between the left and right crawler belts 9 can be expanded and contracted, and an upper revolving body 3 that is pivotally attached to the lower traveling body 1. Expanding / contracting position detecting means 25, 2 for detecting a contracted position, an expanded position, and at least one predetermined position between the crawler belt 9;
The above object is achieved by providing the above-described configuration.

According to the second aspect of the present invention, the ports 10d, 10e, and 10c are provided at at least one of the expanded position, the contracted position, and at least one predetermined position therebetween for expanding and contracting the crawler belt 9.
An expansion / contraction cylinder 10 having an expansion / contraction cylinder 10f
And hydraulic pressure sources 15 and 19 for supplying pressure oil to the pressure sources.
From each port 10d, 10e, 10 of the expansion / contraction cylinder 10
Further, a pressure sensor for detecting the pressure of the pressure oil supplied to each of the pressure sensors f is provided.

According to a third aspect of the present invention, the hydraulic pressure source includes a first hydraulic pressure source 15 for supplying pressure oil for driving the expansion / contraction cylinder 10,
A second hydraulic source 19 for supplying pressure oil to each port 10d, 10e, 10f of the expansion / contraction cylinder 10, and hydraulic sensors 25, 26, 27 from the second hydraulic source 19 to each port 10d of the expansion / contraction cylinder 10. , 10e and 10f are sensors for detecting the oil pressure of the pressure oil supplied to each of the sensors.

Referring to FIG. 7, the invention according to claim 4 is characterized in that the expansion / contraction position detecting means is provided at the hydraulic power source 36, the contracted position, the expanded position of the crawler belt 9 and at least one predetermined position therebetween. Corresponding switching valves 37, 38, 39 for switching the pressure oil from the hydraulic pressure source 36, and a switching unit 6b for switching each switching valve 37, 38, 39 at each position.
Is connected to each of the switching valves 37, 38, and 39,
Pressure sensors 45, 46, 4 for detecting the pressure of pressure oil from
7 In the invention according to claim 5, the predetermined position is an intermediate position between the expansion position and the contraction position.

According to the first aspect of the present invention, the expanded / contracted position detecting means 25, 26, 27 detects the expanded position, the intermediate position of the crawler belt 9, and at least one predetermined position therebetween.

According to the second aspect of the present invention, the hydraulic sources 15, 1
When pressure oil is supplied from 9 to the expansion / contraction cylinder 10, the expansion / contraction cylinder 10 expands / contracts, and the crawler belt 9 expands / contracts. At this time, the pressure of the pressure oil supplied to each port 10d, 10e, 10f of the expansion / contraction cylinder 10 changes according to the expansion / contraction state of the expansion / contraction cylinder 10. This change in oil pressure is detected by the pressure sensor 2
5, 26 and 27, and the position of the crawler belt 9 is detected.

According to the third aspect of the invention, the first hydraulic power source 1
When pressure oil is supplied from 9 to the expansion / contraction cylinder 10, the expansion / contraction cylinder 10 expands / contracts, and the crawler belt 9 expands / contracts. At this time, the oil pressure of the pressure oil supplied from the second oil pressure source 19 to each of the ports 10d, 10e, and 10f of the expansion / contraction cylinder 10 changes according to the expansion / contraction state of the expansion / contraction cylinder 10. The change in the oil pressure is detected by the oil pressure sensors 25, 26, and 27, and the position of the crawler belt 9 is detected.

According to the fourth aspect of the present invention, the switching valves 37, 38, and 39 disposed at the contracted position, the expanded position, and at least one predetermined position between the crawler belt 9 are respectively positioned at the crawler belt 9 position. Switching is performed by the switching unit 6b accordingly. The pressure of the pressure oil switched by the switching valve 6b is detected by the pressure sensors 45, 46, and 47 to detect the position of the crawler belt 9.

In the section of the means for solving the above-mentioned problems, which explains the configuration of the present invention, the drawings of the embodiments of the present invention are used to make the present invention easy to understand. However, the present invention is not limited to this.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. -First Embodiment- FIG. 1 is a diagram showing a configuration of a crawler crane to which a crawler belt stretch detection device for a construction machine according to a first embodiment of the present invention is applied, and FIG. FIG. 3 is a side view of the crawler crane, FIG. 3 is a front view of the crawler crane according to the present embodiment, and FIG.
FIG. 5 is a sectional view taken along line II of FIG. 2 showing a state where the crawler belt is in the intermediate position, and FIG. 6 is a sectional view taken along line II of FIG. 2 showing a state where the crawler belt is in the contracted position. is there. Since FIGS. 2 and 3 have been described in the prior art,
Here, detailed description is omitted.

As shown in FIGS. 1 to 6, the crawler belt stretch detecting device according to the present embodiment comprises a side frame 6, a pin 29,
An expansion / contraction hydraulic cylinder 10 for expanding / contracting the side frame 6 is provided. In FIG. 1, the expansion / contraction hydraulic cylinder 10 includes a cylinder tube 10a, a piston 10b, and a rod 10c. Cylinder 1
A port 10d is formed at the end of the rod chamber 0, a port 10e is formed at a substantially intermediate position of the cylinder 10, and a port 10f is formed at the end of the bottom chamber of the cylinder 10. Port 10
d and 10f are connected to the first hydraulic power source 15 via the switching valve 17, and the port 10e is connected to the first hydraulic pressure source when the cylinder 1 is extended or retracted.
Is connected to a second hydraulic pressure source 19 via a check valve 24 for preventing pressure oil from leaking from the hydraulic pressure source 15. First
The hydraulic source 15 comprises a hydraulic pump 14, a tank T1, and a relief valve 16, and the second hydraulic source 19 comprises a hydraulic pump 18
And a tank T2 and a relief valve 20. Each of the ports 10 d to 10 f is connected to the first and second hydraulic sources 15,
19 is connected.

A pressure detector 25 is connected to a pipe 21 connecting the port 10d and the first hydraulic pressure source 15, and a pressure detector 2 is connected to a pipe 22 connecting the port 10e and the second hydraulic pressure source 19.
6, pressure detectors 27 are connected to the pipes 23 connecting the port 10f and the first hydraulic pressure source 15, respectively.
Each of the pressure detectors 25 to 27 is connected to the controller 56.

The controller 56 is connected to a moment limiter 57 having a memory in which a plurality of rated load curves are stored as a table in accordance with the state of expansion and contraction of the crawler belt 9. The rated load curve is shown in FIG. As shown, the horizontal axis represents the working radius R, and the vertical axis represents the lifting load W, and represents the relationship between the working radius and the lifting load.

Next, the operation of the present embodiment will be described. (1) When the crawler belt is in the extension position The extension operation of the crawler belt 9 is performed as follows. First, the switching valve 17 is switched to the position 17a, pressure oil from the first hydraulic power source 15 is supplied to the bottom chamber of the cylinder 10 from the port 10f, and the expansion / contraction hydraulic cylinder 10 is extended. When the left and right crawler belts 9 reach the extended position, the switching valve 17 is moved to the neutral position 1.
7c, and as shown in FIG. 4, the pin hole 5a formed in the track frame 5 and the pin hole 31d of the link 31 are fixed by the pin 32, thereby connecting the track frame 5 to the left and right side frames 6. Then, the extension operation of the side frame 6, that is, the crawler belt 9 is completed.

After the end of the expansion operation, the piston 10b is located on the rightmost side of the cylinder 10, so that the port 10d is closed. On the other hand, since the pressure oil from the second hydraulic pressure source 19 is supplied to the port 10e, the ports 10e, 1
Pressure is generated in the pipelines 22 and 23 connected to 0f, and no pressure is generated in the pipeline 21. Therefore, the pressure detectors 26 and 27 output a pressure detection signal to the controller, but the pressure detector 25 does not output the pressure detection signal. Here, the pressure detectors 25, 26, 2
7, the one that does not output the pressure detection signal is "0",
If the output is “1” and the extended state of the crawler belt 9 is represented by “0” and “1”, the signal input to the controller 56 is “0-1-1”. The controller 56 can detect that the crawler belt 9 is in the expanded state by the signal of “0-1-1”.

The controller 56 determines these detection signals and outputs an instruction signal to the moment limiter 57. The moment limiter 57 selects a desired rated load curve from a plurality of rated load curves stored in the memory based on an instruction signal from the controller 56, and prevents an overload of the crane based on the rated load curve. In the above case, since the crawler belt 9 is in the extended position, the moment limiter 57 controls the crane boom up / down and the hook up / down based on the rated load curve a.

(2) When the crawler belt is in the middle position The operation of moving the crawler belt 9 to the middle position is performed as follows. First, when the crawler belt 9 is in the contracted position, the switching valve 17
Is switched to the position 17a, the pressure oil from the first hydraulic pressure source 15 is supplied from the port 10f to the bottom chamber of the cylinder 10, and the expansion / contraction hydraulic cylinder 10 is extended. On the other hand, when the crawler belt 9 is in the extended position, the switching valve 17 is switched to the position 17b, the pressure oil from the first hydraulic power source 15 is supplied from the port 10d to the rod chamber of the cylinder 10, and the expansion / contraction hydraulic cylinder 10 To shrink. When the left and right crawler belts 9 reach the intermediate position, the switching valve 17 is returned to the neutral position 17c, and the pin hole 5a formed in the track frame 5, as shown in FIG.
Then, the track frame 5 and the left and right side frames 6 are connected to each other, and the operation of moving the crawler belt 9 to the intermediate position is completed.

After the movement operation to the intermediate position is completed, the piston 10b is located substantially at the center of the cylinder 10, so that the port 10e is closed. On the other hand, since the pressure oil from the second hydraulic pressure source 19 is supplied to the port 10e, pressure is generated in the pipe 22 connected to the port 10e, and
No pressure is generated at 1 and 23. Therefore, the pressure detector 26 outputs a pressure detection signal to the controller 56, but the pressure detectors 25 and 27 do not output the pressure detection signal. Therefore, the pressure detector 2
The signal input to the controller 56 from 5, 26, 27 is "0-1-0". The controller 56 sets this “0
The state where the crawler belt 9 is at the intermediate position can be detected by the signal “−1-0”.

The controller 56 determines these detection signals and outputs an instruction signal to the moment limiter 57. The moment limiter 57 selects a rated load curve b when the crawler belt 9 is at the intermediate position from a plurality of rated load curves stored in the memory in the same manner as described above based on the instruction signal from the controller 56, Lifting is controlled.

(3) When the crawler belt is in the contraction position The contraction operation of the crawler belt 9 is performed as follows. First, the switching valve 17 is switched to the position 17b, pressure oil from the first hydraulic pressure source 15 is supplied from the port 10d to the rod chamber of the cylinder 10, and the expansion / contraction hydraulic cylinder 10 is contracted. When the left and right crawler belts 9 reach the contracted position, the switching valve 17 is moved to the neutral position 1.
7c, and as shown in FIG. 6, the pin hole 5a formed in the track frame 5 and the pin hole 31b of the link 31 are fixed by the pin 32, thereby connecting the track frame 5 to the left and right side frames 6. Then, the contraction operation of the crawler belt 9 is completed.

After the contraction operation is completed, the piston 10b is moved to the position shown in FIG.
Port 1 because it is located at the leftmost
0f is closed. On the other hand, the second hydraulic pressure source 19
Pressure oil is supplied to port 10e,
Pressure is generated in the pipelines 21 and 22 connected to 0d and 10e, and no pressure is generated in the pipeline 23. Therefore, the pressure detectors 25 and 26 output a pressure detection signal to the controller 56, but the pressure detector 27 does not output the pressure detection signal. Therefore, the signal input from the pressure detectors 25, 26, 27 to the controller 56 is "1-1-0", and the controller 56 determines that the crawler belt 9 is in the contracted position by the signal of "1-1-0". Can be detected.

The controller 56 determines these detection signals and outputs an instruction signal to the moment limiter 57.
As described above, the moment limiter 57 selects the rated load curve c when the crawler belt 9 is in the contracted position, and controls the crawler crane's boom up / down and hook lifting / lowering based on the selected rated load curve.

As described above, according to the present embodiment, the pressure oil supplied to the port 10d at the end of the rod chamber of the expansion / contraction cylinder 10, the port 10f at the end of the bottom chamber, and the port 10e at the intermediate position are provided. Since the hydraulic pressure is detected to detect the expanded / contracted state of the crawler belt 9, not only the expanded state and the contracted state of the crawler belt 9 but also the state of the crawler belt 9 at the intermediate position can be detected. Therefore, it is possible to set the lifting ability of the crawler crane suitable for the position where the crawler belt 9 is expanded or contracted according to the detection result.

In the first embodiment, the second hydraulic pressure source 19 only activates the detectors 25, 26 and 27, and the set pressure of the relief valve 20 is the second pressure which causes the cylinder 10 to expand and contract. Relief valve 16 of hydraulic source 15
Can be set much lower than the relief setting pressure of the crawler belt 9, and does not affect the extension / contraction operation of the crawler belt 9.

In the above embodiment, the detection results of the pressure detectors 25, 26, and 27 are input to the controller 56, and the rated load curve is selected by the moment limiter 57 to set the lifting capacity of the crawler crane. However, the detection results of the pressure detectors 25, 26, and 27 may be used for other purposes.

Further, in the first embodiment, for all combinations of the detection results by the pressure detectors 25, 26, 27, it may be determined whether this combination is valid or invalid. That is, as described above, the track 9
“0-1-1”, “0-1-0”, and “1-
When a detection result other than the combination of “1-0” is obtained,
The operation of the crane may be stopped assuming that this detection result is invalid.

-Second Embodiment- Next, a second embodiment of the present invention will be described.
7 to 9 are views showing a configuration of a crawler belt stretch detection device according to a second embodiment of the present invention. In the second embodiment, only the points different from the first embodiment will be described, and the description of the common configuration will be omitted.

As shown in FIGS. 7 to 9, the crawler belt expansion / contraction detecting device according to the second embodiment has a switch for detecting the position of the crawler belt 9 in place of the pressure detectors 25 to 27 in the first embodiment. It is provided with valves 37, 38 and 39. 8 and 9, the controller 56 and the moment limiter 57 are omitted. Switching valves 37, 38, 39
Is connected to a third hydraulic pressure source 36, and the output side is connected to pressure detectors 45, 4 via conduits 41, 42, 43, respectively.
6, 47 are connected. The third hydraulic pressure source 36 includes a hydraulic pump 34, a tank T3, and a relief valve 35. Further, each of the switching valves 37, 38, and 39 is connected to a third hydraulic source 36 and pressure detectors 45, 46, and 47 installed on the upper-part turning body 3 via a hydraulic rotary joint 44. Further, each of the switching valves 37, 38, 39 includes a spring 37c, 38.
c, 39c, usually 37a, 38a, 3 respectively
It has been switched to the 9a side. Also, side frame 6
Is provided with a protruding portion 6b for switching the switching valves 37, 38, 39. In addition, each pressure detector 45, 4
6 and 47 are connected to the controller 56.

Next, the operation of this embodiment will be described. (1) When the crawler belt is in the contracted position First, the crawler belt 9 is contracted in the same manner as in the first embodiment. After the contraction operation, the side frame 6
Is located on the leftmost side of the track frame 5, the projection 6b abuts on the switching valve 37, and the switching valve 37 is switched to the position 37b. As a result, the pressure oil supplied from the third hydraulic pressure source 36 is not supplied to the switching valves 38 and 39 but is supplied only to the pipe 41 via the switching valve 37. No pressure is generated, but pressure is generated in the pipeline 41. Therefore, the pressure detector 45 outputs a pressure detection signal to the controller 56, but the pressure detectors 46 and 47 do not output the pressure detection signal. Therefore, the pressure detectors 45, 46, 47
, The signal that does not output the pressure detection signal is “0”, the signal that outputs the pressure detection signal is “1”, and the expanded state of the crawler belt 9 is represented by “0” and “1”. Becomes “1-0-0”. The controller 56 can detect that the crawler belt 9 is in the contracted state by the signal of “1-0-0”.

The controller 56 discriminates these detection signals and outputs an instruction signal to the moment limiter 57. Based on the instruction signal, the moment limiter 57 performs a rated load curve operation in the same manner as in the first embodiment. Is selected to switch the lifting capacity of the crane.

(2) When the crawler belt is at the intermediate position First, as shown in FIG. 8, the operation of moving the crawler belt 9 to the intermediate position is performed in the same manner as in the first embodiment. After the end of the operation for moving to the intermediate position, the side frame 6 is located at the center of the track frame 5, so that the protruding portion 6b comes into contact with the switching valve 38, and the switching valve 38 is switched to the position 38b. Thus, the pressure oil supplied from the third hydraulic pressure source 36 passes through the switching valve 37 and is not supplied to the switching valve 39 by the position 38b of the switching valve 38. No pressure is generated, but pressure is generated in the conduit 42. Therefore, the pressure detector 46 outputs a pressure detection signal to the controller 56, but the pressure detectors 45 and 47 do not output the pressure detection signal. Therefore, the signals input from the pressure detectors 45, 46, 47 to the controller 56 are "0-1-0". The controller 56 uses the signal of “0-1-0” to control the track 9.
At the intermediate position can be detected.

The controller 56 discriminates these detection signals and outputs an instruction signal to the moment limiter 57. Based on the instruction signal, the moment limiter 57 performs the rated load curve operation in the same manner as in the first embodiment. Is selected to switch the lifting capacity of the crane.

(3) When the crawler belt is in the contracted position As shown in FIG. 9, the crawler belt 9 is contracted in the same manner as in the first embodiment. After the contraction operation, the side frame 6 is located on the rightmost side of the track frame 5, so that the protruding portion 6b contacts the switching valve 39, and the switching valve 39 is switched to the position 39b. Accordingly, the pressure oil supplied from the third hydraulic pressure source 36 is not supplied to the pipelines 41 and 42 but is supplied only to the pipeline 43 via the switching valve 39. No pressure is generated, but pressure is generated in the pipeline 43. Therefore,
The pressure detector 47 outputs a pressure detection signal to the controller 56, but the pressure detectors 45 and 46 do not output a pressure detection signal. Therefore, the pressure detectors 45, 4
The signal input to the controller 56 from 6, 47 is “0”.
−0-1 ”. The controller 56 sets this “0-0-
The signal of “1” can detect that the crawler belt 9 is in the expanded state.

The controller 56 discriminates these detection signals and outputs an instruction signal to the moment limiter 57. Based on the instruction signal, the moment limiter 57 performs a rated load curve operation in the same manner as in the first embodiment. Is selected to switch the lifting capacity of the crane.

In the second embodiment,
The detection results of the pressure detectors 45, 46 and 47 are input to the controller 56, and the rated load curve is selected by the moment limiter 57 to set the lifting capacity of the crane. The 47 detection results may be used for other purposes.

Also in the second embodiment,
As in the first embodiment, the pressure detectors 45, 4
In all combinations of the detection results by 6, 47,
It may be determined whether this combination is valid or invalid. That is, as described above, the result of detection when the crawler belt 9 is at the expanded position, the intermediate position, and the contracted position is “0-0-
If a detection result other than the combination of "1", "0-1-0", and "1-0-0" is obtained, this detection result may be invalid and the crane operation may be stopped. .

Third Embodiment FIG. 10 is a diagram showing a configuration of a crawler belt stretch detection device according to a third embodiment of the present invention. As shown in FIG. 10, in the third embodiment of the present invention, the switching valves 37, 38, and 39 of the second embodiment are provided in the track frame 5, and the switching portion projects from the upper surface of the track frame 5. And the side frame 6 is brought into contact with the switching valve 37,
By switching between 38 and 39, the position of the crawler belt 9 is detected. In the third embodiment, the detection results from the pressure detectors 45, 46, 47 (not shown in FIG. 10) at the expanded position, the intermediate position, and the contracted position of the crawler belt 9 are respectively "0-0- 1 ”,“ 0 ”
-1-1 "and" 1-1-1 ".

Fourth Embodiment FIG. 11 is a diagram showing a configuration of a crawler belt stretch detection device according to a fourth embodiment of the present invention. As shown in FIG. 11, in the fourth embodiment of the present invention, of the switching valves 37, 38, and 39 in the third embodiment, the switching valves 37, 38
Only the switching portion is protruded from the upper surface of the track frame 5 and the side frame 6 is brought into contact with the switching portion to switch the switching valves 37 and 38 so as to detect the expanding / contracting position of the crawler belt 9. In the fourth embodiment, the detection results from the pressure detectors 45 and 46 (not shown in FIG. 11) at the extended position, the intermediate position, and the contracted position of the crawler belt 9 are “0-0” and “0”, respectively. 0-1 ",
It becomes "1-1", and all of the expanded position, the intermediate position, and the contracted position of the crawler belt 9 can be detected by the two pressure detectors 45 and 46.

Fifth Embodiment Next, a fifth embodiment of the present invention will be described.
FIG. 12 is a diagram showing a configuration of a crawler belt stretch detection device according to a fifth embodiment of the present invention. In the fifth embodiment, only points different from the first embodiment will be described.
The description of the common configuration is omitted.

As shown in FIG. 12, the crawler belt stretch detecting device according to the fifth embodiment includes a pressure reducing valve 60 for detecting the position of the crawler belt 9 instead of the pressure detectors 25 to 27 in the first embodiment. It is provided. In FIG. 12, the controller 56 and the moment limiter 57 are omitted. The switching valve 60 is connected to a fourth hydraulic pressure source 61, and the output side is connected to a pressure detector 65 via a pipe 64.
The fourth hydraulic pressure source 61 includes a hydraulic pump 62, a tank T4, and a relief valve 63. Further, the side frame 6 is formed with an inclined portion 6c.
It is in contact with the tip 60a of the rod for changing the secondary pressure of 0. The rod of the pressure reducing valve 60 is urged toward the side frame 6 by a spring (not shown).

Thus, in accordance with the position of the crawler belt 9, the rod of the pressure reducing valve 60 abutting on the inclined portion 6c expands and contracts, and the secondary pressure of the pressure reducing valve 60 changes. The change is detected by the pressure detector 65 to detect the expansion / contraction position of the crawler belt 9. That is, when the crawler belt 9 is in the expanded position, the rod of the pressure reducing valve 60 is in the most expanded state, so that the pressure detected by the pressure detector 65 is small. Since the rod is in the most contracted state, the pressure detected by the pressure detector 65 is large, and when the crawler belt 9 is at the intermediate position, the rod of the pressure reducing valve 60 is at the intermediate position, and is detected by the pressure detector 65. The pressure is intermediate between the expanded and retracted positions. Therefore, by detecting the pressure of the pressure reducing valve 60 with the pressure detector 65, the crawler belt 9 is detected.
Can be detected.

-Sixth Embodiment- Next, a sixth embodiment of the present invention will be described.
FIG. 13 is a diagram illustrating a configuration of a crawler belt stretch detection device for a construction machine according to a sixth embodiment of the present invention. In the sixth embodiment, only the points different from the first embodiment will be described, and the description of the common configuration will be omitted.

As shown in FIG. 13, the crawler belt expansion / contraction detecting apparatus according to the sixth embodiment comprises a variable resistor 48 for detecting the position of the crawler belt 9 in place of the pressure detectors 25 to 27 in the first embodiment. It is provided with. The variable resistor 48 is connected to a power supply 51, and a brush 48a connected to a controller 56 is provided in the variable resistor 48.
The cable 4 from the cable reel 50 of the variable resistor 48
9 is extended, and the distal end of the cable 49 is coupled to a coupling 6d formed on the side frame 6. The variable resistor 48 is rotatably supported by the track frame 5 by the expansion and contraction operation of the side frame 6.
The variable resistor 48, the power supply 51 and the controller 56 are connected via a slip ring 52.

Next, the operation of this embodiment will be described. (1) When the crawler belt is in the extension position First, the crawler belt 9 is extended in the same manner as in the first embodiment. After the end of the extension operation, since the side frame 6 is located on the rightmost side of the track frame 5, the cable 49 of the cable reel 50 is extended most, and the brush 48a of the variable resistor 48 rotates counterclockwise, FIG.
Move to the position shown in. In this state, the power supply 51
And the distance between the brush 48a of the variable resistor 48 and the intermediate position and the contracted position are the largest.
Is the lowest voltage as compared with the intermediate position and the contracted position. The controller 56 can detect that the crawler belt 9 is in the expanded state based on the magnitude of the voltage.

The controller 56 discriminates the detection signal and outputs an instruction signal to the moment limiter 57. Based on the instruction signal, the moment limiter 57 calculates the rated load curve in the same manner as in the first embodiment. Selected,
Switches the lifting capacity of the crane.

(2) When the crawler belt is at the intermediate position First, as in the first embodiment, the operation of moving the crawler belt 9 to the intermediate position is performed. After the end of the operation of moving to the intermediate position, the side frame 6 is located at the intermediate position of the track frame 5, so that the cable 49 of the cable reel 50 is fed or wound up, and the brush 48a of the variable resistor 48 is moved to the side frame. 6 moves to an intermediate position between the expansion position and the contraction position. In this state, since the distance between the power supply 51 and the brush 48a of the variable resistor 48 is located between the expansion position and the contraction position, the voltage input to the controller 56 via the brush 48a is set at the expansion position and the contraction position. It will be something in between. The controller 56 can detect that the crawler belt 9 is at the intermediate position based on the magnitude of the voltage.

The controller 56 discriminates these detection signals and outputs an instruction signal to the moment limiter 57. Based on this instruction signal, the moment limiter 57 performs a rated load curve operation in the same manner as in the first embodiment. Is selected to switch the lifting capacity of the crane.

(3) When the crawler belt is in the contracted position First, the crawler belt 9 is contracted in the same manner as in the first embodiment. After the contraction operation is completed, the side frame 6 is located on the leftmost side of the track frame 5, so that the cable 49 of the cable reel 50 is wound up most. In this state, the power supply 51 and the brush 48 of the variable resistor 48
Since the distance to the position a is the smallest as compared with the intermediate position and the extended position, the voltage input to the controller 56 via the brush 48a is the highest as compared with the intermediate position and the extended position. The controller 56 can detect that the crawler belt 9 is in a contracted state based on the magnitude of the voltage.

The controller 56 discriminates these detection signals and outputs an instruction signal to the moment limiter 57. Based on this instruction signal, the moment limiter 57 performs a rated load curve operation in the same manner as in the first embodiment. Is selected to switch the lifting capacity of the crane.

-Seventh Embodiment- Next, a seventh embodiment of the present invention will be described.
FIG. 14 is a diagram showing a configuration of a crawler belt stretch detection device of a construction machine according to a seventh embodiment of the present invention. In the seventh embodiment, only the points different from the first embodiment will be described, and the description of the common configuration will be omitted.

As shown in FIG. 14, the crawler belt expansion / contraction detecting apparatus according to the seventh embodiment is different from the first embodiment in that a setting switch 7 for setting the expansion / contraction state of the crawler belt 9 by an operator.
1, 72 and 73 are provided. Then, the controller 56 detects the expansion / contraction state of the crawler belt 9 based on the detection signals of the pressure detectors 25, 26, 27 and the detection signals of the setting switches 71, 72, 73, and outputs a detection signal to the moment limiter 57. To select the rated load curve.

In selecting the rated load curve, in the present embodiment, the detection signals of the pressure detectors 25, 26 and 27 are compared with the detection signals of the setting switches 71, 72 and 73, and each detector and The rated load curve is selected by the moment limiter 57 only when the detection signals from the setting switches match. That is, when the crawler belt 9 is in the extended position, the detection signals of the pressure detectors 25, 26, and 27 are "0-1-1", so that the setting switches 71, 72,
Only when the detection signal of 73 is “0-1-1”, the selection of the rated load curve is performed. When the crawler belt 9 is at the intermediate position, the detection signals of the pressure detectors 25, 26, and 27 are "0-
1-0 ", the selection of the rated load curve is performed only when the detection signals of the setting switches 71, 72, 73 are" 0-1-0 ". Further, when the crawler belt 9 is in the contracted position, the detection signals of the pressure detectors 25, 26, and 27 are "1-1".
−0 ”, the selection of the rated load curve is performed only when the detection signals of the setting switches 71, 72, 73 are“ 1-1-0 ”.

On the other hand, if the detection signals of the pressure detectors 25, 26 and 27 do not match the detection signals of the setting switches 71, 72 and 73, it is possible that an abnormality has occurred in the expansion / contraction operation of the crawler belt 9. Due to the high performance, the controller 56 interrupts all operations by stopping the engine of the crane itself.

The setting switches 71, 72, 73 in the seventh embodiment may be provided in any of the second to sixth embodiments other than the seventh embodiment. Also.

According to the seventh embodiment, the crawler 9
And setting switches 58, 59, 60,
The load rating curve is selected only when the information input from the crawlers matches the information input from the setting switches 58, 59, and 60. When the information input from the setting switches 58, 59, and 60 does not match, the crane operation is performed. Is stopped, the work can be immediately stopped when the movement of the crawler belt 9 is abnormal.

In the correspondence between the above embodiment and the claims, the pressure detectors 25, 26, 27, 45, 46, 47,
The variable resistor 48 and the pressure reducing valve 60 each constitute an expansion / contraction position detecting means.

[0062]

As described above in detail, according to the present invention, not only the expanded state and the contracted state of the crawler belt but also the state of the crawler belt at a predetermined position therebetween are detected by the expansion / contraction position detecting means. Therefore, it is possible to set the work suitable for the predetermined position, such as setting the lifting capacity of the crane suitable for the predetermined position.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a crawler crane to which a crawler belt stretch detection device for a construction machine according to a first embodiment of the present invention is applied.

FIG. 2 is a side view of the crawler crane according to the embodiment.

FIG. 3 is a front view of the crawler crane according to the embodiment.

FIG. 4 is a diagram showing an expanded state of a crawler belt;

FIG. 5 is a view showing an intermediate state of a crawler belt;

FIG. 6 is a view showing a contracted state of a crawler belt;

FIG. 7 is a diagram showing a configuration of a crawler belt stretch detection device of a construction machine according to a second embodiment of the present invention (when contracted).

FIG. 8 is a diagram showing a configuration of a crawler belt stretch detection device of a construction machine according to a second embodiment of the present invention (intermediate time).

FIG. 9 is a diagram showing a configuration of a crawler belt stretch detection device of a construction machine according to a second embodiment of the present invention (when expanded).

FIG. 10 is a diagram showing a configuration of a crawler belt stretch detection device of a construction machine according to a third embodiment of the present invention.

FIG. 11 is a diagram showing a configuration of a crawler belt stretch detection device of a construction machine according to a fourth embodiment of the present invention.

FIG. 12 is a diagram showing a configuration of a crawler belt stretch detection device of a construction machine according to a fifth embodiment of the present invention.

FIG. 13 is a diagram showing a configuration of a crawler belt stretch detection device of a construction machine according to a sixth embodiment of the present invention.

FIG. 14 is a diagram showing a configuration of a crawler belt stretch detection device of a construction machine according to a seventh embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Lower traveling body 3 Upper revolving structure 5 Track frame 6 Side frame 9 Crawler belt 10 Cylinder 25, 26, 27, 45, 46, 47 Pressure detector 37, 38, 39 Switching valve 60 Pressure reducing valve

Claims (5)

[Claims] 1. A lower traveling body in which the interval between left and right crawler belts can be expanded and contracted, an upper revolving body pivotally attached to the lower traveling body, a contracted position, an expanded position of the crawler belt, and at least one of them. A crawler belt stretch detection device for a construction machine, comprising: an expansion / contraction position detecting means for detecting a predetermined position. 2. An expansion / contraction cylinder for expanding / contracting the crawler belt, the expansion / contraction cylinder having a port in at least one of an expansion position, a contraction position, and at least one predetermined position therebetween, and a hydraulic source for supplying pressure oil to the expansion / contraction cylinder. The construction machine according to claim 1, wherein the expansion / contraction position detection means further includes a pressure sensor for detecting a pressure of hydraulic oil supplied from the hydraulic pressure source to each of the ports of the expansion / contraction cylinder. Crawler belt stretch detection device. 3. The hydraulic pressure source comprises a first hydraulic pressure source for supplying pressure oil for driving the expansion / contraction cylinder, and a second hydraulic pressure source for supplying pressure oil to each port of the expansion / contraction cylinder, The crawler belt extension / contraction detection of a construction machine according to claim 2, wherein the hydraulic pressure sensor is a sensor that detects a hydraulic pressure of hydraulic oil supplied from the second hydraulic pressure source to each of the ports of the expansion / contraction cylinder. apparatus. 4. The system according to claim 1, wherein the expansion / contraction position detecting means includes: a hydraulic pressure source;
A switching valve corresponding to each of the three predetermined positions, for switching the pressure oil from the hydraulic pressure source, a switching unit for switching the respective switching valves at the respective positions, and a pressure from the hydraulic source connected to the respective switching valves. The crawler belt stretch detection device for a construction machine according to claim 1, further comprising a pressure sensor that detects oil pressure. 5. The crawler belt stretch detection device according to claim 1, wherein the predetermined position is an intermediate position between the expansion position and the contraction position.