JPS6147781B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a traveling crane having a power supply cable branch point on the ground.

Conventionally, as shown in FIG. 1, a cable lamp 1 of a power supply cable 1 is
A method has been adopted in which a buffer spring 3 is installed in the section a using a link mechanism 2, and fluctuations in cable tension transmitted via a guide roller 4 are alleviated by compressing the spring 3 using the link motion. However, it has not been sufficient to sufficiently alleviate the impactive cable tension that occurs when the crane passes the branch point 5 of the power supply cable at high speed so as not to cause damage to the cable. That is, for example, the branch point 5 is
When trying to pass at high speed in the direction of arrow A in the figure, the cable 1 is not wound up properly by the cable take-up reel 1b, and the cable 1 becomes slack 6 from the state shown in FIG. 2 to the state shown in FIG. After 5 passes, this slack 6 minutes is suddenly pulled, creating a large cable tension.

The object of the present invention is to sufficiently prevent damage to the cable due to the shocking and large cable tension that occurs when a crane passes through a branch point of the power supply cable.

The key point of the present invention is to increase the torque of the torque motor for cable winding control near the branch point of the cable, and to eliminate the slack in the cable by winding it with the high torque of the torque motor when passing the branch point. It is.

An embodiment of the present invention will be described below with reference to FIGS. 4 to 7.

FIG. 4 shows an overall explanatory diagram. The limit switch 9 installed on the reel 8 that winds the cable 13 of the crane 7 detects the cable winding length, and when the cable winds within a distance of L from the branch point 5 of the power supply cable, the rotation of the reel 8 and the control torque are controlled. The torque value 11 of the motor 22 is increased to 12 to eliminate slack in the cable 13. As is well known, the winding length of the cable 13 is expressed by the winding diameter when the cable 13 is wound around the reel 8, and the limit switch 9 may detect this winding diameter.

Furthermore, the shock-absorbing spring 15 installed at the cable clamp 19 can reduce the impactive cable tension when the crane 7 passes directly above the power supply cable branch point 5.

FIG. 5 shows a detailed view of the limit switch 9 portion. The middle of the lever 14 attached to the cable 13 wound inside the reel 8 is attached to the bracket 17 via the rotation fulcrum 24, and the striker 16 at the rear end of the lever 14 is connected to the limit switch 9 installed on the bracket 17 to rotate the lever 14. ON,
Guess I can turn it off. A spring 23 is installed between the lever 14 and the bracket 17, and the lever 1
4 is always pressed against and along the cable 13.

FIG. 6 shows a block diagram of the control mechanism. When the crane 7 is at a distance L from the cable branch point 5, the limit switch 9 is turned on, and the ON signal S is turned on.
is sent to the control device 20, and the control device 20 outputs a signal S' to increase the rotational torque T to the control torque motor 22 that rotationally drives the reel 8.

Figure 7 shows a detailed view of the cable clamp section. The cable 13 wound around the reel 8 is fixedly supported by a cable clamp 19 via a guide roller 18 on the ground. This spring 15 is interposed between the cable clamp 19 and a horizontally protruding bracket 21 fixedly installed at the branch point 5.
For this reason, when the cable 13 is pulled upward in FIG. 7, the spring 15 is compressed via the cable clamp 19, so that the tension on the cable is relieved.

According to this embodiment, as the crane 7 moves and winds the cable 13 into the reel 8, the winding diameter of the cable 13 gradually becomes larger. With this increase in diameter, cable 1
The end of the lever 14, which is pressed against the lever 3 by the force of the spring 23, rotates upward about the rotational fulcrum 24. For this purpose, the striker 16 formed at the other end of the lever 14 rotates in the direction of pushing down the switch lever of the limit switch 9 (from the position indicated by the chain line in FIG. 5 to the position indicated by the solid line). Then, when the crane 7 moves from the branching point 5 to the distance inside L and winds the cable 13 into the reel 8, the rotation of the lever 14 increases in proportion to the amount of winding. Finally, the switch lever of limit switch 9 is pushed down to turn limit switch 9 ON. When the limit switch 9 is turned on, the ON signal S is sent to the control device 20.
This input causes the control device 20 to apply a torque value higher than the previously generated torque value 11 (shown in FIG. 4) to the control torque motor 22 that rotates the reel 8 in the direction of winding the cable 13. It outputs a signal S' that generates 12. Therefore, reel 8 rotates cable 1 with greater rotational force than before.
3 can be quickly wound up to prevent slack from occurring in the cable 13. Therefore, an excessive cable tensile force generated as a reaction due to slack in the cable 13 after passing through the branch point 5 is prevented, and the tensile force on the cable 13 is also alleviated by the spring 15, so that the cable 13 is further relaxed. The cable tensile force relaxation effect is improved. When the crane 7 passes the branch point 5 and moves away to the opposite side by a distance of more than L, the lever 14 is reversed, the limit switch 9 is turned OFF, and the reel 8 is controlled to rotate with the normal torque value 11, returning to the normal state. Become. The same applies when the crane 7 is sent backwards.

Since the torque generated by the torque motor 22 is switched high or low at the ON timing of the limit switch 9, it can be done automatically and accurately. In addition, since the torque is set to high even before sagging occurs, unnecessary tension is not applied to the cable 13.
This can improve economic efficiency.

As can be seen from the above, the distances L, L before and after the branch point 5 are expressed by the winding length of the cable 13 onto the reel 8, and are equal to or greater than a predetermined value. This length is represented by the winding diameter of the cable 13 on the reel 8, and is greater than or equal to a predetermined value. The case of forward movement and the case of reverse movement are substantially the same. Since a limit switch is used to detect the winding diameter, it can be detected with a simple configuration.

As described above, according to the present invention, it is possible to prevent the cable from sagging near the branch point of the cable, and therefore to prevent the tension of the cable from becoming excessive. Further, since the detecting means near the branch point is a limit switch that detects the winding diameter of the cable on the reel, detection can be performed with a simple configuration.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view of a branch point equipped with a conventional cable tension relaxation device, Fig. 2 is a cable state diagram in a normal tensioned state, and Fig. 3 is a cable state diagram in a slack state. FIG. 4 is a diagram showing the relationship between the cable handling device and the cable winding reel drive control motor torque according to one embodiment of the present invention, and FIG.
Fig. 6 is a control block diagram of the torque motor for drive control of the cable winding reel shown in Fig. 4, and Fig. 7 is an enlarged view of the cable take-up reel shown in Fig. 4. It is an enlarged view. 7... Crane, 8... Reel, 9... Limit switch, 11, 12... Torque value, 13...
Cable, 14...Lever, 15...Spring, 16
...Striker, 17...Bracket, 19...
...Cable clamp, 20...Control device, 22...
...Torque motor.

Claims (1)

[Claims] 1 A movable body is equipped with a reel rotationally driven by a torque motor, and a cable fed out from the reel is fixed to a fixed point on the ground side in the middle of the travel range of the movable body, wherein the A limit switch is provided between the movable body and the reel to detect whether a distance from a fixed point to the reel is within a predetermined value, and a signal indicating that the limit switch is within the predetermined value is provided. A protection device for a power supply cable of a moving body, characterized in that a control circuit is provided for increasing the output of the torque motor to a high torque when the torque motor is outputting high torque.