JPH09323890A - Crane cylinder stroke detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately and continuously detect expanding and contracting conditions of a cylinder used for construction machines and make it difficult to be effected from the exterior and not give any adverse effect to the people in the surrounding. SOLUTION: A sensor rod 13 is provided in parallel with the piston rod 12 of a hydraulic cylinder 11 and the one of the ends of the sensor rod 13 is bent and fixed to a piston rod end 12a. A sealed up type sensor tube 15 is securely provided on the extension line of the sensor rod 13 on the side of a cylinder case 14 and the sensor rod end 13b is inserted into the interior of the sensor tube 15 from one of the ends 15a of the sensor tube 15. A detection unit 16 for detecting the position of the sensor rod end 13b without making contact with it is provided on the other end of the sensor tube 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder stroke detection device for a crane, and more particularly to a cylinder stroke detection device that is less susceptible to external influences.

[0002]

2. Description of the Related Art Construction machines such as cranes have
Many hydraulic or pneumatic cylinders are used. When detecting the expansion / contraction state of these cylinders, a cylinder stroke detection device as shown in FIGS. 9 to 11 is provided as necessary.

In the cylinder stroke detection device of FIG. 9, a rotary type detector 3 such as a potentiometer or a rotary encoder is fixed to a cylinder case 2 of a hydraulic cylinder 1, and a sensing rope 4 of the rotary type detector 3 is attached to a piston rod 5. It is attached to the tip 5a. When the hydraulic cylinder 1 operates and the piston rod 5 moves, the sensing rope 4 is pulled out or wound up. The rotary detector 3 calculates the stroke position of the hydraulic cylinder 1 based on the amount of extension of the sensing rope 4.

The cylinder stroke detection device shown in FIG.
A sensor rod 6 is provided in parallel with the piston rod 5, one end 6a of the sensor rod is fixed to the tip 5a of the piston rod, and the tip 6b of the sensor rod is extended to the outer surface of the cylinder case 2. Further, on / off type detectors 7 and 8 such as limit switches and proximity sensors are arranged on the extension of the sensor rod 6 on the side of the cylinder case 2. In the illustrated example, limit switches are used as the on / off type detectors 7 and 8.

When the hydraulic cylinder 1 operates and the piston rod 5 moves, the sensor rod 6 also moves integrally with the piston rod 5. For example, when the hydraulic cylinder 1 contracts, the tip 6b of the sensor rod first passes the position (a) closest to the on / off type detector 7, so that the on / off type detector 7 is turned on. Further, when the hydraulic cylinder 1 continues to contract, the tip 6b of the sensor rod passes the position (b) in the immediate vicinity of the on / off type detector 8, and the on / off type detector 8 is also turned on. In this way, the position of the tip 6b of the sensor rod is detected by turning on / off the plurality of on / off type detectors 7 and 8, and the stroke position of the hydraulic cylinder 1 is calculated.

The cylinder stroke detecting device shown in FIG.
The roller 9 is brought into contact with the piston rod 5, and the roller 9
The rotary detector 3 is connected to the rotary shaft of the. When the hydraulic cylinder 1 operates and the piston rod 5 moves, the roller 9 rotates in either forward or reverse direction. The rotary detector 3 calculates the stroke position of the hydraulic cylinder 1 based on the rotation speed and the rotation direction of the roller 9.

[0007]

In the conventional cylinder stroke detecting device shown in FIG. 9, since the sensing rope is exposed, another object may come into contact with the sensing rope, and the sensing rope is disconnected. There is also.
In that case, an error occurs in the detection result, and the accurate cylinder stroke position cannot be calculated.

Further, the cylinder stroke detecting device shown in FIG. 10 detects the position of the tip of the sensor rod by turning on / off the on / off type detector, so that the cylinder stroke position is intermittently detected. Therefore, in order to detect the cylinder stroke finely, many on-off type detectors must be installed, resulting in an increase in cost and maintenance.

On the other hand, the cylinder stroke detecting device shown in FIG. 11 can continuously detect the cylinder stroke, but since the roller is in contact with the piston rod, the roller is slippery due to the adhesion of oil or the like. Error occurs in the detection result, and an accurate cylinder stroke position cannot be calculated.

In addition to this, it is conceivable to detect the movement of the piston rod by irradiating the laser beam. However, if the laser beam is radiated at the exposed portion, the laser beam may have a bad influence on the surrounding people. .

Therefore, there is provided a cylinder stroke detecting device for accurately and continuously detecting the expansion / contraction state of a cylinder used in a construction machine, being less susceptible to external influences, and having no adverse effect on the surrounding people. There are technical issues that need to be resolved in order to provide
An object of the present invention is to solve this problem.

[0012]

DISCLOSURE OF THE INVENTION The present invention has been proposed in order to achieve the above object. A sensor rod is provided in parallel with a piston rod of a cylinder, and one end of the sensor rod is fixed to a tip of the piston rod. At the same time, the tip of the sensor rod is extended to the outer surface of the cylinder case, and on the other hand, on the side of the cylinder case, a closed type sensor tube is fixed on the extension line of the sensor rod. The tip of the sensor rod is inserted into the inside of the sensor tube, the tip of the sensor rod is formed to be movable inside the sensor tube, and the position of the tip of the sensor rod is not in contact with the other end inside the sensor tube. Provided is a cylinder stroke detection device for a crane, which is provided with a detection unit for detection.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a cylinder stroke detection device 10, in which a sensor rod 13 is provided in parallel with a piston rod 12 of a hydraulic cylinder 11, and one end 1 of the sensor rod is provided.
3a is bent and fixed to the tip 12a of the piston rod. The tip 13b of the sensor rod is extended to the outer surface of the cylinder case 14.

On the other hand, on the side of the cylinder case 14, the closed type sensor tube 1 is provided on the extension line of the sensor rod 13.
5 is fixed to the inside of the sensor tube 15 from one end 15a of the sensor tube to the tip 13b of the sensor rod.
Insert Then, as shown in FIG. 2, when the hydraulic cylinder 11 operates and the piston rod 12 moves, the sensor rod 13 also moves integrally with the piston rod 12.
At this time, the tip 13b of the sensor rod is formed so as to be able to move smoothly inside the sensor tube 15.

Further, at the other end 15b of the sensor tube,
A detection unit 16 is provided that detects the position of the tip 13b of the sensor rod in a non-contact manner. The detection unit 16 emits ultrasonic waves or laser light to the object to be measured, detects the intensity of reflected waves from the object to be measured, and outputs a signal as a change in voltage or current. Based on the signal, the control unit (not shown) calculates the distance to the object to be measured. In addition, by detecting the strength of the reflected wave from the measured object,
The signal may be D-converted and output as a BCD (binary coded decimal code).

That is, when the piston rod 12 moves and the cylinder stroke changes, the signal output by the detection unit 16 changes accordingly. For example, as shown in FIG. 1, when the tip 12a of the piston rod projects from the cylinder case 14 to the leftmost end in the figure, as shown in the graph of FIG. M
IN), and it is calculated that the cylinder stroke T is the longest position.

When the piston rod 12 contracts to the right in FIG. 1, the output signal S of the detector 16 gradually decreases as shown in FIG. Further, as shown in FIG. 2, when the tip 12a of the piston rod is contracted to the position where it is closest to the cylinder case 14, as shown in FIG. )
Therefore, it is calculated that the cylinder stroke T is the shortest position.

In FIG. 3, the output signal S decreases as the cylinder stroke T becomes longer.
As shown in, even when the output signal S increases as the cylinder stroke T becomes longer, the cylinder stroke T can be calculated from the output signal S from the detection unit 16 as described above. Further, the relationship between the output signal S and the cylinder stroke T does not necessarily change linearly but may change in a quadratic curve. In any case, the cylinder stroke T can be continuously detected by the change of the output signal S.

When the power of the cylinder stroke detecting device 10 is turned off due to work interruption or work stoppage, the output signal S of the detector 16 becomes zero. But,
If the cylinder stroke detection device 10 is turned on by restarting the work, the tip 13b of the sensor rod at that time is turned on.
Since the output signal S is output from the detection unit 16 in accordance with the position of, the cylinder stroke T is accurately calculated when the power is turned on again despite the power being turned off once.

Furthermore, since the sensor tube 15 is of a hermetically sealed type, there is no risk that ultrasonic waves or laser light emitted from the detection section 16 will leak to the outside of the sensor tube 15. Further, even when another object comes into contact with the sensor tube 15 or there is another disturbance, the detection signal of the detection unit 16 is not affected, and the reliability is improved as compared with the conventional type.

Next, an example in which the cylinder stroke detection device 10 of the present invention is applied to a crane will be described. FIG. 5 shows the crawler crane 21, with a boom 23 at the front of the main body 22.
Is mounted rotatably back and forth, and a mast boom 24 and a high mast 25 are rotatably mounted back and forth at the rear position of the boom 23. A weight carriage 26 is provided at the rear of the main body 22.
Is being towed.

Then, the hook rope 28 is extended from the winch unit 27, and the hook 2 is attached to the tip of the boom 23.
9 to suspend the rear end of the boom 23 and the mast boom 2
Boom pendant rope 30 is connected between the front end of 4 and the front end. Further, the rear end of the mast boom 24 and the high mast 25 are connected by a mast pendant rope 31, and the rear end of the mast boom 24 and the weight carriage 26.
And are connected by a suspension pendant rope 32.

Here, a boom back stop 33 is interposed between the boom 23 and the main body 22, and the lower part of the rear surface of the boom 23 is supported so that the boom 23 does not exceed the maximum angle. As shown in FIG. 6, the boom back stop 33 is connected to the body 22 side of the cylinder case 3.
4 and a piston rod 35 protruding from the cylinder case 34. The tip 35a of the piston rod is connected to the boom 23 side, and the piston rod 35 is provided with a coil spring 36.

The cylinder stroke detecting device 10 is attached to the boom back stop 33, and one end 13a of the sensor rod 13 is connected to the tip 35a of the piston rod.
The sensor tube 15 is fixed to the side of the cylinder case 34 while being fixed to the. Then, when the boom 23 undulates, the rod 35 expands and contracts following it,
The sensor rod 13 also expands and contracts integrally with the rod 35. Therefore, as described above, the cylinder stroke of the boom back stop 33 can be continuously detected based on the output signal of the detection unit 16.

On the other hand, as shown in FIG. 5, a weight carriage 26 is towed at the rear of the main body 22 of the crawler crane 21, and wheels 37 of the weight carriage 26 are provided with a traveling mechanism and a steering mechanism. There is.

7 and 8 show a traveling mechanism and a steering mechanism of the wheels 37, and as shown in FIG. 7, a bracket 40 is pivoted in a horizontal direction on a carriage frame 38 via a turning bearing 39. Put on the bracket 4
0, the suspension cylinder 41 is arranged downward, and the arm 42 is pivoted sideways. This arm 4
The piston rod 43 of the suspension cylinder 41 is connected to the intermediate portion of the wheel 2, and the wheel 37 is attached to the tip of the arm 42.
Attach the hub 44 of. Wheel 37 has hydraulic motor 45
Is installed.

The bogie frame 3 is connected to the suspension cylinder 41 and the hydraulic motor 45 via a rotary joint 46.
Pressure oil is supplied from the 8 side, the vertical movement of the wheel 37 received from the ground is buffered by the suspension cylinder 41, and the wheel 37 is rotationally driven by the hydraulic motor 45.

Further, the suspension cylinder 41 is equipped with the cylinder stroke detecting device 10, and one end 13a of the sensor rod 13 is connected to the tip 4 of the piston rod.
The sensor tube 15 is fixed to the side of the cylinder case 47 while being connected to 3a. The cylinder stroke detecting device 10 can continuously detect the cylinder stroke of the suspension cylinder 41.

As shown in FIG. 8, one end 52a of a link arm 52 is pivotally attached to the carriage frame 38, and the other end 52b of the link arm 52 is connected to the upper end of the column 51 via the link arm 53. ing. A tip 54a of the piston rod of the steering cylinder 50 is pivotally attached to the intermediate portion 52c of the link arm 52.

Further, the cylinder stroke detecting device 10 is mounted on the steering cylinder 50, and one end 13a of the sensor rod 13 is connected to the tip 54 of the piston rod.
The sensor tube 15 is fixed to the side of the cylinder case 55 while being connected to a.

Here, when the steering cylinder 50 is contracted, the link arm 52 rotates rightward in the figure around the one end portion 52a. At this time, the column 51 is pushed rightward via the link arm 53 connected to the other end 52b of the link arm 52, so that the column 51 is integrated with the bracket as shown by the two-dot chain line in FIG. 40 rotates clockwise around the rotary joint 46. On the other hand, when the steering cylinder 50 is extended, the bracket 38 rotates counterclockwise about the rotary joint 46.

As described above, the expansion and contraction of the steering cylinder 50 causes the bracket 40 to rotate in the horizontal direction, so that the wheel 37 can be turned by an arbitrary angle. Then, from the stroke displacement of the steering cylinder 50,
The turning angle and turning direction of the wheel 37 are calculated.

The present invention can be variously modified without departing from the spirit of the present invention, and it goes without saying that the present invention extends to the modified ones.

[0034]

As described above, according to the present invention, the sensor rod moves integrally with the piston rod of the cylinder, and the position of the tip of the sensor rod is detected in a non-contact manner by the detection portion provided inside the sensor tube. The cylinder stroke is calculated based on the output signal from the detection unit. When the cylinder stroke detection device is powered on, a signal is continuously output from the detection unit, so that the cylinder stroke can be continuously detected. Further, even when the power is turned off once, if the power is turned on again, the cylinder stroke at that time is accurately calculated.

On the other hand, although ultrasonic waves and laser light are emitted from the detection section, since the sensor tube is a closed type, these ultrasonic waves and laser light do not leak to the outside of the sensor tube and the surroundings. There is no fear of adversely affecting humans. Further, even when another object comes into contact with the sensor tube or other disturbance occurs, the detection by the detection unit is not affected, and the reliability is improved as compared with the conventional type.

Since the sensor rod and the detecting portion are integrally provided on the sensor tube, the work of mounting the cylinder stroke detecting device is extremely simple and the maintenance is easy. It is also possible to detect the total length by mounting it on a stretchable object such as a pipe and rod, and it is also possible to detect the stretchable length other than the cylinder.

[Brief description of drawings]

FIG. 1 is a side view of a cylinder stroke detection device according to an embodiment of the present invention, in which a cylinder is extended.

FIG. 2 is a side view of the cylinder stroke detection device with the cylinder contracted.

FIG. 3 is a graph showing an example of a relationship between an output signal of a detection unit and a cylinder stroke.

FIG. 4 is a graph showing another example of the relationship between the output signal of the detection unit and the cylinder stroke.

FIG. 5 is a side view of the crawler crane.

FIG. 6 is a side view of a boom back stop equipped with a cylinder stroke detection device.

FIG. 7 is a side view of a suspension cylinder equipped with a cylinder stroke detection device and a traveling mechanism of wheels.

FIG. 8 is a side view of a steering cylinder equipped with a cylinder stroke detection device and a wheel steering mechanism.

FIG. 9 is a side view showing an example of a conventional cylinder stroke detection device.

FIG. 10 is a side view showing another example of the conventional cylinder stroke detection device.

FIG. 11 is a side view showing still another example of the conventional cylinder stroke detection device.

[Explanation of Codes] 10 Cylinder Stroke 11 Hydraulic Cylinder 12 Piston Rod 12a Piston Rod Tip 13 Sensor Rod 13a Sensor Rod One End 13b Sensor Rod Tip 14 Cylinder Case 15 Sensor Tube 15a Sensor Tube One End 15b Sensor Tube Other End 16 Detection unit

Claims (1)

[Claims] 1. A sensor rod is provided parallel to a piston rod of a cylinder, one end of the sensor rod is fixed to a tip of the piston rod, and the tip of the sensor rod is extended to an outer surface of a cylinder case. A sealed sensor tube is fixed to the side of the cylinder case on the extension line of the sensor rod, and the tip of the sensor rod is inserted into the sensor tube from one end of the sensor tube. A cylinder stroke detection device for a crane, wherein the inside of the tube is movably formed, and a detection unit for detecting the position of the tip of the sensor rod in a non-contact manner is provided at the other end inside the sensor tube.