JP2909926B2 - Load drop prevention device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load drop prevention device attached to a hoist.

[Prior art]

In a hoist, a drum, a rope, a wire, and the like, which are usually wound on a rotating shaft having side plates extending radially outward at both ends and integrally mounted on a rotating shaft that is normally and reversely rotated by a drive control device, are provided. The operation of the rotary shaft and the drum (forward rotation, reverse rotation and stop) can be controlled by the drive control device. Thus, in the hoist, for example, when the drive control device is abnormal (when the mechanism for stopping the rotating shaft is out of order)
The drum rotates in a free state, and the load rapidly drops due to its own weight. In order to solve such a problem, an apparatus for preventing a rapid drop of a load has been proposed in Japanese Utility Model Publication No. 56-24719.

[Problems to be solved by the invention]

By the way, the above-mentioned conventional fall prevention device is provided with a cam, a brake mounting plate, and a disk with internal teeth provided separately from the drum on the rotating shaft, and is mounted on the brake mounting plate to brake the disk with internal teeth. A brake shoe, and a pawl mounted on a body that rotatably supports the rotating shaft, engaged with the cam, and engaged with the internal teeth of the disk when the rotating shaft is rapidly rotated. Since the parts are new and are provided separately from the components of the hoist, a relatively large mounting space is required, as well as pawls, discs with internal teeth, brake shoes, brake mounting plates, and rotating parts. Since the configuration is such that the drum is braked through a large number of components such as a shaft, there is a concern about reliability. The present invention has been made to address the above-described problem, and has as its object to provide a compact and highly reliable load drop prevention device.

[Means for Solving the Problems]

In order to achieve the above object, in the present invention,
A load is unloaded by a hoisting rope such as a rope or a wire wound around a drum that has side plates extending radially outward at both ends and is integrally assembled on a rotating shaft that is rotated forward and reverse by a drive control device. In the hoist that was
It has a sensor for directly detecting the rotation speed of the drum itself, and a brake shoe capable of holding the side plate in the direction of the rotation axis. The actuator is actuated by an actuator to hold the side plate with the brake shoe for braking. And a control device that activates the actuator when the rotation speed detected by the sensor reaches a set value, to thereby constitute a load drop prevention device.

[Action and Effect of the Invention]

In the load drop prevention device according to the present invention, when the rotation speed of the drum itself directly detected by the sensor reaches the set value, the control device operates the actuator, so that the brake device is operated and the side plate of the drum is operated. Is braked. Therefore, when the drive control device is abnormal in the hoist (when the mechanism for stopping the rotating shaft is broken), even if the drum rotates in a free state, the load drop prevention device according to the present invention reduces the rotational speed of the drum to the set value. Maintained below, the load is prevented from dropping rapidly due to its own weight. By the way, in the load drop prevention device according to the present invention, the side plate of the drum, which is a basic component of the hoist, can be used as a part to be braked as it is, and the side plate can be sandwiched in the rotation axis direction. Since the side plate is braked by a brake device that can be configured compactly around the side plate with a suitable brake shoe, the load drop prevention device can be configured compactly, and even in a small mounting space. Can be implemented. Further, in the load drop prevention device according to the present invention, the side plate of the drum is braked by the brake device, and since the drum is directly braked by the brake device, the reliability of the device can be improved. In addition, since the rotation speed of the drum itself is directly detected by the sensor, the rotation of the drum itself can be accurately detected even when the drum becomes rotatable with respect to the rotation axis, and the sensor output is output. And the drum can be accurately braked by the brake device, and the reliability of the device can be greatly improved.

【Example】

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the hoisting machine A shown in FIG. 1, a rotating shaft which is rotated forward and reverse by a drive control device 11 operated by an operator.
A drum 13 is integrally mounted on 12. Drum 13
Is a body 13a fitted on the rotating shaft 12 so as to transmit torque.
And a pair of disk-shaped side plates 13b, 13c integrally formed at both ends of the body portion 13a and extending radially outward, and formed by the body portion 13a and both side plates 13b, 13c. A required amount of hoisting ropes 14 such as ropes and wires for discharging and unloading the load W is wound around the recess. In addition, the base end of the hoisting rope 14 is fixed to the drum 13, and the load W
A hook 15 for suspending is fixed. In this embodiment, the sensor S and the brake device B are arranged on the outer peripheral portion of the right side plate 13b in FIG. 1, and the control device C is arranged on the drive control device 11. . The sensor S is for directly detecting the rotation speed of the drum 13 itself from the movement of the concavo-convex belt 16 attached to the side surface of the side plate 13b in a ring shape, and the detected speed signal is output to the control device C. Is configured. As shown in FIGS. 1 and 2, the brake device B uses the side plate 13b as a brake rotor, that is, holds the side plate 13b in the rotation axis direction to perform braking. It is composed of calipers 21 and 22 and brake shoes 23 and 24, and is configured to be operated by the operation of the electric actuator D. The calipers 21 and 22 are attached to a guide rail 25 fixed to one side of the drive control device 11 at the base so as to be movable only in the left and right directions in the drawing, and are provided at the tip end facing the outer peripheral side surface of the side plate 13b. The brake shoes 23 and 24 are respectively fixed. Note that a sensor S is attached to the tip of the caliper 22 on the right side in the figure. The electric actuator D, whose operation (energization) is controlled by the control device C, is a pinion that is integrally rotatably mounted on the electric motor 26 and an output shaft of the electric motor 26 (which is in a free state when not energized). The pinion 27 always meshes with racks 21a and 22a formed at the bases of the calipers 21 and 22. As a result, when the output shaft of the electric motor 26 rotates clockwise in FIG. 2, the calipers 21 and 22 move in the direction of the arrow in the drawing, and the side plates 13b are sandwiched and braked by both brake shoes 23 and 24. You. The control device C drives the electric motor 26 so that its output shaft rotates clockwise in FIG. 2 when the rotation speed of the drum 13 itself is directly detected by the sensor S. In the present embodiment, an energization holding circuit is provided so that energization of the electric motor 26 is maintained unless the reset switch 28 is operated. In the present embodiment configured as described above, the sensor S
When the rotation speed of the drum 13 itself, which is directly detected by the controller 13, reaches the set value, the control device C activates the electric actuator D, so that the brake device B operates to brake the side plate 13b of the drum 13. . Therefore, when the drive control device 11 is abnormal in the hoisting machine A (for example,
When the rotating shaft 12 rotates in a free state due to a failure of the mechanism for stopping the drum 12), even if the drum 13 rotates in the free state, the rotation speed of the drum 13 is reduced by the load drop prevention device according to the present invention. The load W is maintained at or below the set value (this value is determined by the performance of the electric actuator D and the brake device B and may or may not stop the drum 13), and the load W is rapidly reduced due to its own weight. Is prevented from falling. By the way, in this embodiment, the side plate 13b of the drum 13, which is a basic component of the hoist A, can be used as a part to be braked as it is, and the side plate 13b can be clamped in the rotation axis direction. Brake shoes 23,
Since the side plate 13b is braked by the brake device B which can be configured compactly around the side plate 13b having 24, the load drop prevention device according to the present invention can be configured compactly, It can also be implemented in space. Further, since the side plate 13b of the drum 13 is braked by the brake device B, and the drum 13 is directly braked by the brake device B, the reliability of the load drop prevention device according to the present invention can be improved. In addition, since the rotation speed of the drum 13 itself is directly detected by the sensor S, even when the drum 13 becomes rotatable with respect to the rotation shaft 12 (when the connection between the drum 13 and the rotation shaft 12 is abnormal), The rotation of the drum 13 itself can be accurately detected, and the reliability of the sensor output can be improved. In addition, the drum 13 can be accurately braked by the brake device B, and the reliability of the device can be greatly improved. it can. In the above embodiment, the control device C is provided with an energization holding circuit so that the electric actuator D and the brake device B are maintained in the operating state when the rotation speed of the drum 13 once exceeds the set value. However, it is also possible to implement the present invention without providing the power supply holding circuit in the control device C.
In this case, the electric actuator D and the brake device B
Repeatedly operates and deactivates, and the rotation speed of the drum 13 is maintained at a substantially set value. Therefore, it is necessary to set the set value in consideration of this. The number of brake devices may be plural.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram schematically showing an embodiment of the present invention,
FIG. 2 is an enlarged view of the main part. DESCRIPTION OF SYMBOLS 11 ... Drive control device, 12 ... Rotary shaft, 13 ... Drum, 13
b, 13c: side plate, 14: hoisting rope, wire, etc., W: load, A: hoisting machine, B: brake device, C: control device, D: (electric) actuator ,
S ... Sensor.

──────────────────────────────────────────────────の Continued on the front page (58) Fields surveyed (Int. Cl. ⁶ , DB name) B66D 1/54 B66D 5/00 B66D 5/02 B66D 5/12 B66D 5/14

Claims (1)

(57) [Claims] 1. A hoisting rope such as a rope or a wire wound on a drum having side plates extending radially outward at both ends and integrally mounted on a rotating shaft which is normally and reversely rotated by a drive control device. In a hoist adapted to discharge and unload a load, a sensor for directly detecting the rotation speed of the drum itself, and a brake shoe capable of holding the side plate in a rotation axis direction, are operated by an actuator. A load drop prevention device comprising a brake device for clamping the side plate by the brake shoe and braking, and a control device for operating the actuator when a rotation speed detected by the sensor reaches a set value. .