JPH08113472A - Wire drum of electric hoist - Google Patents

Abstract

PURPOSE: To improve safety as well as to enhance work efficiency by decreasing the waiting time of an operator through a process of changing the hoisting speed of a wire drum of an electric hoist according to cargo handling work. CONSTITUTION: The diameters of wire drums 9 are made different from each other so that the diameter of the wire drum 9 for sequentially lifting hoisting loads by in the lateral direction by hoisting wire ropes 5 on screw-like grooves 11 provided on the peripheral surface may be formed into a large diameter part on a hoisting starting part Wl of the hoisting wire ropes 5, which is the part of about 1/3 of the hoisting width of the wire drums 9, and it may be formed into a small diameter part on a winding terminal part W3 of the hoisting wire ropes 5, which is the part of about 1/3 of the hoisting width of the wire drum 5. The transferring part W2 from the large diameter part to the small diameter part is formed into a tapered shape. Therefore, the hoisting speed of the hoisting wire drum 5 is increased on the large diameter part, and the hoisting speed of the hoisting wire drum 5 is decreased on the small diameter part, and work efficiency of a cargo handling worker is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a wire drum of an electric hoist in which a hoisting wire rope is sequentially wound laterally to lift a load.

[0002]

2. Description of the Related Art An example of a conventional electric hoist in which a hoisting wire rope is sequentially wound in a lateral direction to lift a load will be described with reference to FIG. The drive mechanism of the electric hoist includes a hoisting electric motor 1 including a three-phase squirrel-cage induction motor, a speed reducer 2 that reduces the rotational force of the hoisting electric motor 1, and a rotational force that is reduced by the speed reducer 2. Is transmitted to the wire drum 3 and a magnet brake 4 for braking the hoisting motor 1.

Then, one end 5a of the hoisting wire rope 5 is fixed to the wire drum 3 by appropriate means, and the other end 5b is fixed to the drum case 7 via the hook block 6. Then, the load is hoisted down by the rotational force from the drive mechanism section.

In this case, in order to prevent a large force from being applied to one end 5a of the hoisting wire rope 5, even if the hook block 6 is hoisted down to a specified lifting height, the wire drum 3 is wound more than two times. The upper winding wire rope 5 is left, and the wind-up effect is ensured, which results in the frictional force between the wire drum 3 and the winding wire rope 5.

Such a conventional wire drum 3 is generally formed in a cylindrical shape, and the winding start portion (the left side of the wire drum in FIG. 4) of the winding wire rope 5 is also the winding end portion (the wire in FIG. 4). Also on the right side of the drum, the diameter D of the pitch circle of the wire drum 3 (see FIG. 5), that is, from the substantial axis of the wire rope 5 when the hoisting wire rope 5 is wound around the wire drum 3 to the approximate axis of the wire rope 5. The diameter D of the wire drum 3 is the same.

Flange portions 3a, 3a are formed on both sides of the wire drum 3 and the wire drum 3
A screw-shaped groove 8 for guiding the winding of the winding wire rope 5 is cut on the circumferential surface of the winding wire rope 5, and the winding wire rope 5 is wound around the groove 8 in a single layer.

The shape of the screw-shaped groove 8 provided on the circumferential surface of the wire drum 3 will be described with reference to FIG.
Is set to be slightly larger than the diameter d of the hoisting wire ropes 5 so that the wire ropes 5 do not come into contact with each other, and the height c of the groove 8 thereof is set to about 1/3 of the diameter d of the hoisting wire ropes 5, The groove bottom radius R is formed to be slightly larger than the radius r of the hoisting wire rope 5.

The hoisting speed of the conventional electric hoist thus constructed is usually a single speed because the wire drum 3 has a cylindrical shape if the number of revolutions of the hoisting motor 1 is constant. .

In order to change the hoisting speed of the electric hoist having such a structure, a pole number conversion type electric motor is adopted as the hoisting motor 1, and the number of poles is converted to change the speed.
It is known that the power supply frequency is variable by using an inverter and the variable frequency is supplied to the hoisting motor to control the speed.

[0010]

In such a conventional single-speed type electric hoist, the hoisting speed is constant regardless of whether the hoist is loaded or unloaded, which causes a waiting time for the cargo worker. However, there was a problem that work efficiency was poor. Further, in the variable speed electric hoist, there is a problem that the cost increases because the pole number conversion type electric motor and the inverter are used for controlling the hoisting speed of the electric hoist.

Further, the frictional force between the wire drum and the hoisting wire rope in the all-wound portion of the hoisting wire rope fixed to the wire drum, the larger the frictional force applied to the end of the hoisting wire rope. This is desirable for safety, and when hoisting a hoisted load with an electric hoist, the sling wire rope (the rope that hangs on the hook of the hoisting wire rope) becomes tense, so The hoisting operation is stopped immediately before leaving the floor surface, and the hoisting operation is performed so that the impact at the time of ground cutting (when the hoisted load leaves the floor surface) is reduced and the hoisted load is not suddenly lifted.
Workers often perform abrupt ground clearance work after being pushed by cargo handling work. In such a case, a large force is applied to the slinging wire rope and the hoisting wire rope due to the impact at the time of ground cutting, which is not preferable for safety. However, in the conventional electric hoist, there is a problem in that, in this respect, no particular safety consideration is given to the structure.

The present invention has been made in order to solve the above-mentioned conventional problems, and can easily change the hoisting speed according to the actual cargo handling work to reduce the waiting time of the cargo handling worker and improve the work efficiency. It is an object of the present invention to provide a wire drum of an electric hoist capable of increasing the safety of the electric hoist.

[0013]

According to the first aspect of the present invention,
In an electric hoist in which a thread-shaped groove is provided on the peripheral surface of the wire drum and the winding wire rope is sequentially wound in the groove in the lateral direction to lift the load, the diameter of the pitch circle of the groove of the wire drum is set. The winding start portion of the winding wire rope is formed in a large diameter portion, and the winding end portion of the winding wire rope is formed in a small diameter portion,
The transition portion from the large diameter portion to the small diameter portion is formed in a tapered shape.

According to a second aspect of the invention, the groove shape of the all-winding portion of the wire drum for winding the winding wire rope is V.
It is characterized by having a shape.

According to a third aspect of the present invention, the screw-shaped groove provided on the peripheral surface of the wire drum for winding the hoisting wire rope is formed into a step shape, and the groove radius of the first step is the radius of the hoisting wire rope. Form the same diameter as the radius or slightly larger than this,
The radius of the groove bottom of the second step is slightly smaller than the radius of the hoisting wire rope.

[0016]

According to the invention of claim 1, at the time of winding,
During empty operation until the wire rope for sling tensions,
The hoisting wire rope is wound on the large diameter part of the wire drum and hoisted at high speed. Then, the hoisting wire rope is sequentially moved to the taper portion of the wire drum and wound up, and during steady operation after ground cutting, the hoisting wire rope is wound up at a small diameter part of the wire drum at a low speed. Roll up.

Further, during steady operation at the time of lowering,
Rewind the hoisting wire rope from the small diameter part of the wire drum and lower it at a low speed. After the hoisting wire rope is gradually moved to the taper portion of the wire drum and unwound, the hoisting wire rope is moved to the large diameter portion of the wire drum during an empty load operation until the sling wire rope relaxes. Rewind more and lower at high speed.

According to the second aspect of the invention, when a load acts on the hoisting wire rope at the all-winding portion of the hoisting wire rope fixed to the wire drum,
The hoisting wire rope increases the frictional force between the hoisting wire rope and the hoisting wire rope due to the wedge effect of the bite in the V groove of the wire drum.

Further, in the invention described in claim 3, during the empty operation, the hoisting wire rope is wound around the groove of the first stage of the wire drum and hoisted and unwound, and during the load operation, the hoisting wire rope is hoisted. The wire rope is wound around the groove on the second stage of the wire drum and wound up and down.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a wire drum of an electric hoist according to the present invention will be described below with reference to FIGS. The same members as those in FIGS. 4 and 5 are designated by the same reference numerals in the following description. FIG. 1 is a vertical cross-sectional view in which a part of a wire drum according to the present invention is cut away, FIG. 2 is a detailed view of a groove of a fully wound portion, and FIG. FIG. Note that FIG. 4 is also referred to in this embodiment.

In FIG. 1, reference numeral 9 is a cast wire drum around which the hoisting wire rope 5 is wound.
A drum body 9a is formed in the central portion, and flanges 9b, 9b for preventing the hoisting wire rope 5 from falling off are formed on both sides of the drum body 9a.

Reference numerals 9c and 9c are support walls formed on the inner peripheral portion of the drum body 9a, and boss portions 9d and 9d for drum support are formed at the tip end portions thereof. The bosses 9d, 9d are rotatably supported by a bracket (not shown) of the hoisting motor 1 and a bracket (not shown) of the speed reducer 2 via bearings (not shown).

The drum body 9a of the wire drum 9 is shown in FIG.
As shown in Fig. 1, the winding start portion W1 (Fig. 1) of the winding wire rope 5 which is about 1/3 of the winding width of the wire drum 9
Left side) and about 1/1 of the winding width of the wire drum 9
Winding end part W3 of the wire rope 5 for winding which becomes 3
(The right side in FIG. 1) has a different diameter.

More specifically, this is a hoisting wire rope 5
The diameter D1 of the pitch circle of the wire drum 9 at the winding start portion W1 is the large diameter portion, and the diameter D2 of the pitch circle of the wire drum 9 at the winding end portion W3 of the winding wire rope 5 is the small diameter portion. The transition portion W2 from the large diameter portion to the small diameter portion is formed in a tapered shape.

When the electric hoist is used as a hoist for a crane, the diameter D of the pitch circle of the wire drum 9 (see FIG. 5 showing the conventional one) and the hoist wound into the wire drum 9 The minimum value of the value D / d of the ratio with the diameter d of the wire rope 5 is specified by the crane structure standard. Therefore, in the wire drum 9 according to the present invention, the diameter of the pitch circle of the winding end portion of the winding wire rope 5
D2 will satisfy this specified value.

Next, the groove in the all-winding portion W4 (first two windings of the winding start portion W1) of the wire drum 9 for winding the winding wire rope 5 will be described with reference to FIG.

The groove has a substantially V shape as shown in FIG. 2, and the winding wire rope 5 is wound around the V groove 10. Therefore, when a load acts on the hoisting wire rope 5, the hoisting wire rope 5 and the V
The frictional resistance generated between the groove 10 and the groove 10 increases, and the force applied to the end of the hoisting wire rope 5 is greatly reduced.

Next, the screw-shaped groove formed on the peripheral surface of the drum body 9a of the wire drum 9 will be described with reference to FIG.
The groove 11 has a stepped shape as shown in the figure,
There are two stages, the first stage groove 11a and the second stage groove 11b.
The radius R1 of the groove 11a in the first step is the same as or slightly larger than the radius r of the wire rope 5 for hoisting, and the groove bottom radius R2 of the groove 11b in the second step is for hoisting. It is formed to be slightly smaller than the radius r of the wire rope 5.

Therefore, when the hoisting wire rope 5 is not loaded, the hoisting wire rope 5 is wound up in the groove 11a of the first stage of the wire drum 9, and the hoisting wire rope 5 is wound. A gap g is formed between the second groove 11b and the second groove 11b.

When a load is applied to the hoisting wire rope 5, the hoisting wire rope 5 slightly changes into the gap g, and the second groove 11b of the wire drum 9 is changed.
To be wound up. At this time, the hoisting wire rope 5 is in a state of entering the gap g, so that the shock during ground cutting is absorbed. That is, the amount of tightening of the hoisting wire rope 5 into the gap g of the wire drum 9 absorbs the impact at the time of ground cutting.

On the other hand, the pitch p'of the thread-shaped groove 11 is formed slightly larger than the diameter d of the hoisting wire rope 5, and the height c'of the groove 11 is larger than the diameter d of the hoisting wire rope 5. Is also slightly lower. The height c ′ of the groove 11 of the transition portion W2 from the large diameter portion to the small diameter portion is set to the winding start portion W1 and the winding start portion W1 excluding the all-winding portion W4 in order to prevent the winding wire rope 5 from coming off. It is desirable to form it slightly higher than the winding end portion W3.

The operation of the wire drum 9 of the electric hoist thus constructed will be described. When winding the hoisting wire rope 5 around the wire drum 9, one end of the hoisting wire rope 5 is fixed to the starting end portion of the winding start portion W1 of the wire drum 9 having a large diameter by an appropriate means. Winding part
After being wound around the V groove 10 (two windings) of W4, the wire rope 9 has a threaded groove 11 of a large diameter portion, a threaded groove 11 of a tapered transition portion W2, and a wire drum of a small diameter portion. The winding end portion W3 of the winding No. 9 is sequentially wound around the screw-shaped groove 11.

Then, as shown in FIG. 4, a hook block 6 is attached to a portion of the hoisting wire rope 5 which is suspended, and the end of the hoisting wire rope 5 is fixed to the drum case 7. Therefore, when the wire drum 9 is rotated by the driving force from the hoisting electric motor 1 of the hoisting drive mechanism (not shown), the hoisting wire ropes 5 are sequentially wound in the direction of arrow X in FIG. Will be done.

At the time of hoisting, the hoisting wire rope 5 is wound around the large diameter portion of the wire drum 9 and is operated at a high speed during an empty load operation until the slinging wire rope becomes tense. . That is, if the rotation speed of the rotating shaft of the hoisting electric motor 1 is constant, the large-diameter portion rotates faster, and thus the high-speed operation is performed. In this way, the hoisting wire rope 5 sequentially moves to the taper portion of the wire drum 9 and is wound up. At the time of steady operation after ground cutting, the hoisting wire rope 5 is wound around the small diameter portion of the wire drum 9. It will be taken and run at low speed.

When a load acts on the hoisting wire rope 5 at the all-wound portion of the hoisting wire rope 5 fixed to the wire drum 9, when the hoisting wire rope 5 is loaded.
Will enter into the V groove 10 of the wire drum 9, and the frictional force between the wire drum 9 and the hoisting wire rope 5 can be further increased, and a large force will not be applied to the one end 5a of the hoisting wire rope 5. Like .

Further, during the empty operation, the hoisting wire rope 5 is wound up in the groove 11a of the first stage of the wire drum 9 and hoisted and unwound. It is wound up in the groove 11b of the second stage of the drum 9 and wound up and down.

[0037]

Since the present invention is constructed as described in detail above, it has the following effects. According to the first aspect of the invention, the hoisting speed is simply changed according to the actual cargo handling work, and the wire rope for slinging is operated at a high speed during an empty load until it is tensioned or loosened. It is possible to increase the work efficiency by reducing the load, and to operate at a low speed in the steady state after ground cutting to slow down the moving speed of the load and improve the safety.

According to the second aspect of the present invention, at the all-wound portion of the hoisting wire rope fixed to the wire drum, the hoisting wire rope bites into the V groove of the wire drum, thereby hoisting the wire drum. Since the frictional force of the working wire rope can be further improved, the force applied to the end portion of the hoisting wire rope can be reduced and the safety can be improved.

According to the third aspect of the present invention, during the load operation, the hoisting wire rope is wound around the second groove of the wire drum and hoisted and unwound. Since it is possible to absorb impact force, it is possible to improve safety.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view in which a part of a wire drum according to an embodiment of the present invention is cut away.

FIG. 2 is a vertical cross-sectional view showing in detail the groove of the all-wound portion of the one shown in FIG.

FIG. 3 is a vertical cross-sectional view showing in detail a screw-shaped groove provided on the peripheral surface of the wire drum of FIG.

FIG. 4 is a schematic view showing a mechanism of a conventional electric hoist.

FIG. 5 is a vertical cross-sectional view showing a part of a screw groove of a conventional wire drum.

[Explanation of symbols]

 5 Winding wire rope 9 Wire drum 10 V groove 11 Screw groove 11a 1st groove 11b 2nd groove D1 Pitch circle diameter D2 Pitch circle diameter

Claims (3)

[Claims] 1. An electric hoist in which a thread-shaped groove is provided on a peripheral surface of a wire drum, and a winding wire rope is sequentially wound in the groove in a lateral direction to lift a load,
The diameter of the pitch circle of the groove of the wire drum is formed in the large diameter portion at the winding start portion of the winding wire rope, and is formed in the small diameter portion at the winding end portion of the winding wire rope. A wire drum for an electric hoist, characterized in that a transition portion from a large diameter portion to a small diameter portion is formed in a tapered shape. 2. The wire drum for an electric hoist according to claim 1, wherein the groove shape of the all-winding portion of the wire drum for winding the hoisting wire rope is V-shaped. 3. The screw groove provided on the peripheral surface of the wire drum for winding the hoisting wire rope has a step shape, and the radius of the groove of the first step is the same as or smaller than the radius of the hoisting wire rope. The wire drum of an electric hoist according to claim 1, wherein the groove bottom radius of the second stage is formed slightly smaller than the radius of the hoisting wire rope.