JPH1111883A - Self-weight falling speed control device of hoist gear - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a self-weight falling speed control device of a hoist gear which can make constant the falling speed through prevention of its rising when a fall is made while the self-weight of an object to be lifted is applied in the event of power interruption, etc., and can establish stable self-weight falling. SOLUTION: A common terminal 60 and normal open terminal 61 of a switching relay 6 are connected to one feeder cable leading to the stator coil 7 of an induction motor 25, and one end of a capacitor 5 is connected to the normal close terminal 62 while the other end is connected to another feeder cable. In the event of power interruption, etc., coil energization of the relay 6 will also be turned off, so that the stator coil 7 is separated from the current feed side to cause the applicable end to be in connection with the capacitor 5, and a closed circuit is established. If the brake of a hoist gear is disengaged and the self-weight of an object to be lifted is allowed to act on, a fall takes place with no power supplied, and the induction motor 25 rotates in following motions to work as a generator. The regenerative power flows through the closed circuit to result in a thermal energy consumption, and it is possible to exert a braking force well balanced and stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a self-weight descent speed control device for a hoist attached to a load such as a gondola and raising and lowering the same. The present invention relates to a gravity descent speed control device for a hoist capable of adjusting the speed.

[0002]

2. Description of the Related Art Some hoists for raising and lowering cargo such as gondola have a sheave for winding a wire rope, and a wire rope suspended from a rooftop of a building is wound around the sheave. It is known that the wire rope is moved by moving the wire rope up and down by rotating the sheave by rotating the sheave by utilizing the frictional force therebetween.

[0003] For example, as shown in FIG. 2, a gondola 1 is suspended and moved up and down for work on an outer wall of a building.
Are provided on the left and right sides, respectively, and the two wire ropes 3, 3 suspended from the roof of the building are taken into the hoists 2, 2, respectively, whereby the gondola 1 is moved up and down. An auxiliary rope 4 for double safety is hung along each wire rope 3, and the auxiliary rope 4 is passed through an auxiliary lock side of a lock device arranged above the hoist 2, The double operation is performed together with the main lock side through the wire rope 3.

The hoist 2 has a sheave 22 in a machine casing 21 as shown in FIGS. Sheave 22
, A groove portion in which the wire rope 3 is sandwiched is formed by a leaf spring. The machine frame 21 is rotatably accommodated via a bearing 23, and a number of guide rollers 24 are arranged facing the groove portion of the sheave 22. Then, the wire rope 3 wound around the groove portion of the sheave 22 is pressed by the guide roller 24. An induction motor 25 and a cyclo reduction gear 26 are attached to the machine frame 21 with the sheave 22 interposed therebetween. The induction motor 25 is a three-phase motor whose output shaft 27 is connected to a mechanical brake 28 and a clutch. 2
9 is connected to the input side at the center of the cyclo reducer 26, and the output side at the outer periphery of the cyclo reducer 26 is connected to the sheave 22.
It is connected integrally with. For this reason, when the induction motor 25 is started, the sheave 22 is rotated, and the groove portion of the sheave 22 is in contact with the wound wire rope 3 by frictional force. Can be moved up and down.

The mechanical brake 28 is mechanically pressed against the sheave 22 to perform a braking operation by the friction thereof. When the electromagnetic coil is energized, the mechanical pressing is released and the brake is released. Has become. For this reason, when power is turned off due to a power failure or the like, the mechanical brake 28 enters a brake operation state, and the sheave 22 is brake-locked. However, the cyclo reduction gear 26 is provided with a connecting portion 261 of a handle, and the handle is connected to the connecting portion 261 to release the brake lock of the mechanical brake 28 and to manually operate the handle to thereby move the sheave 22. The motor can be rotated at a predetermined reduction ratio.

[0006]

However, in such a conventional hoist, when the power is turned off due to a power failure or the like, the sheave 22 is rotated by manually operating the handle as described above. Although the load such as the gondola 1 can be moved, the steering wheel must be given a large amount of rotation because the reduction ratio of the cyclo reducer 26 is set large. Therefore, there is a problem that manual operation is troublesome and time-consuming.

By the way, if the brake lock of the mechanical brake 28 is released and the hand is released from the handle when the power is turned off due to a power failure or the like, the sheave 22 becomes freely rotatable, and the self-weight of the gondola 1 is actuated to reduce the power. In this case, the vehicle can be quickly lowered without power without manual operation by human power, but the increase in speed cannot be controlled. Then, when the descent speed rises above a predetermined value, the lock device disposed above the hoist 2 operates, and the wire rope 3 and the auxiliary rope 4
Is mechanically locked, and the elevating operation becomes impossible.

In view of the above-mentioned problems, the present invention can prevent a rise in the descent speed and make it constant when a descent is carried out by applying the weight of the luggage when power is turned off during a power failure or the like. It is an object of the present invention to provide a gravity descent speed control device for a hoist capable of stably gravity descent.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to a sheave which is attached to a luggage such as a gondola and is suspended from an upper part of a building or the like by a sheave rotatably driven by an induction motor. A self-weight descent speed control device for a hoist that raises or lowers the load by winding or rewinding while controlling winding and rotation, wherein a capacitor connected to a stator coil of an induction motor to form a closed circuit, and a hoist, Switching means for disconnecting the stator coil from the power supply side and connecting to the capacitor when the battery is inactive due to power-off is provided.

[0010] Therefore, in the self-weight descent speed control device of the hoist of the present invention, when power is turned off due to a power failure or the like, the switching means disconnects the stator coil from the power supply side and connects to the capacitor to form a closed circuit. At this time, if the brake lock of the hoist is released and the weight of a load such as a gondola is applied, it moves in the descent direction without power, and the induction motor also rotates accordingly. Since the stator coil of the induction motor is cut off from the power supply side to form a closed circuit with the capacitor, the induction motor becomes a generator, and the regenerative power generated by the induction motor as it rotates dependently is closed. It flows through the circuit and is consumed as heat energy by the resistance of the stator coil. Therefore, in the induction motor, generation of regenerative electric power and consumption as heat energy are balanced, and a stable braking force can be exhibited.

[0011]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a configuration diagram showing one embodiment of a self-weight descent speed control device in a hoist of the present invention.

This self-weight descent speed control device is shown in FIGS.
This is applied to the above-described hoisting machine 2 and the like, and is provided with a condenser 5 and a switching relay 6, which are connected to the induction motor 25, and are used when the load (the gondola 1) descends by acting on its own weight. The regenerative electric power generated by the induction motor 25 is consumed.

That is, the switching relay 6 is connected to the common terminal 6
0 and a normally open terminal 61 are interposed in one of the power supply lines connected to the stator coil 7 of the induction motor 25, and are connected so as to disconnect the stator coil 7 from the power supply side when the coil excitation is off. One end of the capacitor 5 is connected to the normally closed terminal 62 of the switching relay 6, and the other end of the capacitor 5 is connected to another one of the power supply lines connected to the stator coil 7.

With the above configuration, in the self-weight descent speed control device of the hoist of the present embodiment, the coil excitation of the switching relay 6 is also turned off when the power is turned off such as a power failure.
The connection of the common terminal 60 is switched from the normally open terminal 61 side to the normally closed terminal 62 side. Therefore, the stator coil 7 is disconnected from the power supply side, and the end is connected to the capacitor 5 to form a closed circuit. At this time, if the brake lock of the mechanical brake 28 is released and the hand is released from the handle for manual operation set on the cyclo reducer 26, the sheave 22 becomes freely rotatable. The motor rotates in the descending direction, and the induction motor 25 also rotates accordingly. And
Since the stator coil 7 of the induction motor 25 is separated from the power supply side and forms a closed circuit with the capacitor 5, the induction motor 25 becomes a generator, and the regenerative electric power generated by the induction motor 25 as it rotates dependently. Flows through the closed circuit and is consumed as heat energy by the resistance of the stator coil 7. Therefore, in the induction motor 25, generation of regenerative electric power and consumption as heat energy are balanced, and a stable braking force can be exerted. Therefore,
When descending by applying the own weight of the luggage when power is turned off due to a power failure or the like, the speed of the self-weight drop can be prevented from rising and can be kept constant, and the self-weight drop can be performed stably. At this time, by changing the capacity of the capacitor 5, the equilibrium point of the heat energy consumption can be shifted, whereby the speed of the self-weight descent can be appropriately adjusted and optimized. For this reason, for example, if the condenser 5 is configured as a variable-capacity type so that the capacity can be appropriately changed and operated, the operator who got on the gondola 1 can operate the gondola 1 to adjust the descent speed arbitrarily.

The construction of the hoisting machine 2 is not limited to the one utilizing the frictional force with the sheave, but may be appropriately changed such as winding up or rewinding on a drum. Therefore, the handle for manual operation is not required, and the cyclo reducer 26 may have a configuration in which the connecting portion 261 of the handle is removed, thereby reducing the weight. And can be simplified, which can contribute to a reduction in cost. Furthermore, since the hoist 2 is equipped with a lock device for locking the wire rope 3 and the auxiliary rope 4 independently of each other as double safety, when the self-weight descent speed control device of the present invention is provided, It is also possible to adopt a configuration in which the mechanical brake 28 is omitted. In this case, the configuration can be further simplified, and there is an advantage in terms of weight reduction and cost reduction.

[0016]

As described above, in the present invention,
When power is turned off due to a power failure or the like, the switching means disconnects the stator coil from the power supply side and connects to a capacitor to form a closed circuit. Therefore, if the brake lock of the hoist is released and the weight of the load such as a gondola is applied, it moves in the descent direction without power and the induction motor also rotates dependently, and at this time, the induction motor becomes a generator, The regenerative power generated by the induction motor as it rotates dependently flows through its closed circuit and is consumed as thermal energy by the resistance of the stator coil. Therefore, in the induction motor, generation of regenerative electric power and consumption as heat energy are balanced, and a stable braking force can be exhibited. Therefore, when the load is lowered by applying its own weight when the power is turned off due to a power failure or the like, it is possible to prevent the speed of the self-weight descent from rising and to keep it constant, so that the self-weight descent can be performed stably. At this time, by changing the capacity of the capacitor, it is possible to shift the equilibrium point of the heat energy consumption, whereby the speed of the self-weight descent can be appropriately adjusted, and it is possible to optimize the speed. To play.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of a self-weight descent speed control device in a hoist of the present invention.

FIG. 2 is a perspective view of a gondola showing an application of a conventional hoist.

FIG. 3 is a sectional view of a hoist applied to the gondola shown in FIG. 2;

FIG. 4 is a cross-sectional view of the hoist shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Gondola 2 Winding machine 3 Rope (wire rope) 5 Capacitor 6 Switching means (switching relay) 7 Stator coil 25 Induction motor

Claims (1)

[Claims] 1. A rope attached to a luggage such as a gondola and hung from an upper part of a building or the like is wound around a sheave rotatably driven by an induction motor, and is wound up or rewinded while controlling the rotation. A self-weight descent speed control device for a hoist that lifts and lowers a load, comprising: a capacitor connected to a stator coil of the induction motor to form a closed circuit; and a stator when the hoist becomes inactive due to energization off. Switching means for disconnecting a coil from a power supply side and connecting the coil to the capacitor;