JPH025678B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in an electric hoist for hoisting heavy objects.

(Prior Art) In a conventional general electric hoist, as shown in FIG. 2, one end of a drive shaft 32 of a winding drum 31 supported by a frame 30 faces a motor core 33 fixed to the frame side. Disc 40 with rotor 34
It is locked with a key so that it can slide in the axial direction. A brake plate 35 is provided on the back side of the disc 40, and when the power is not energized, the force of the spring 36 presses the brake plate 35 against the inner surface of the motor cover 37 as shown in the figure, and the winding drum 3
1, while the rotor 34 is prevented from rotating when energized.
The structure is such that the brake is released by utilizing the fact that the motor core 33 is drawn toward the motor core 33 by electromagnetic force. However, in such a conventional electric hoist, if the motor core 33 is not energized, the winding drum 3
Since the rotor 34 cannot be rotated, the rotor 34 must be actively rotated even when it is desired to slightly lower a lifted heavy object, and even if the switch is turned on and off momentarily, the The amount of descent was several centimeters, and it was impossible to control it to within a few millimeters.

(Problems to be Solved by the Invention) The present invention has been completed with the aim of solving the above-mentioned conventional problems and providing an electric hoist that can lower a lifted heavy object very little at a time. .

(Means for Solving the Problems) The present invention has a disk with a rotor attached to the drive shaft of the winding drum in a slidable manner and facing a motor core fixed to the frame side, and a disk with a rotor attached to the back side of the disk. This electric hoist is equipped with a brake plate that is pressed against the inner surface of the motor cover by a spring when the power is not applied, and is characterized by a solenoid installed on the motor cover that forcibly slides the disk against the spring toward the motor core. That is.

(Embodiment) Next, the present invention will be explained in detail with reference to the illustrated embodiment. 1 is a frame, 2 is a winding drum supported inside the frame 1 by a bearing 3, etc., and 4 is a deceleration mechanism (not shown). This is a drive shaft that rotates the winding drum 2 via the winding drum 2. The tip of the drive shaft 4 is a spline shaft 5, and a disk 7 with a rotor 6 is attached to this portion so that it can slide in the axial direction but cannot rotate relative to it. This rotor 6 is provided to face a motor core 9 fixed to a flange portion 8 of the frame 1, and when the motor core 9 is energized, it constitutes an electric motor and drives the drive shaft 4 through the disk 7. It is something that is rotated. Further, a brake plate 10 is attached to the back of this disc 7, and a spring 11 is attached when the power is not energized.
The motor cover 12 is pressed against the inner surface of the motor cover 12 to prevent rotation of the drive shaft 4, and a brake is applied to prevent the winding drum 2 from rotating due to the weight of the lifted heavy object.

The above configuration is basically the same as that of a conventional electric hoist of this kind, but in the present invention, the end of the disc 7 is exposed outward from the center of the motor cover 12 to form the protrusion 13. , install the solenoid 14 on the motor cover 12, and attach the fulcrum 1
The protrusion 13 via the lever 16 supported by the
The structure is such that the brake plate 10 and rotor 6 can be forcibly slid together with the disk 7 toward the motor core 9 side.

(Function) The motor core 9 configured in this way
When energized, the rotor 6 installed opposite to it
is drawn to the motor core 9 side and rotates by electromagnetic force to rotate the drive shaft 4, and drives the winding drum 2 through a deceleration mechanism to wind up a heavy object, while stopping the energization. For example, a disc 7 slidably mounted on the drive shaft 4 is pressed toward the motor cover 12 by a spring 11, and the brake plate 10 is pressed against the inner surface of the motor cover 12, thereby closing the drive shaft 4 and the winding drum 2. There is no difference in preventing the rotation of a conventional electric hoist. However, in the present invention, if the solenoid 14 is operated in the de-energized state to forcibly slide the disk 7 toward the motor core 9, the brake plate 10 gradually separates from the inner surface of the motor cover 12, and the braking force is released. As a result, the winding drum 2 begins to rotate slightly due to the weight of the lifted heavy object. At this time, since the motor core 9 is not energized, the drive shaft 4 is in a state where an engine brake is applied, so that the winding drum 2 rotates extremely slowly and the heavy object cannot be lowered gradually. It becomes possible. Furthermore, if the operation of the solenoid 14 is stopped, the brake plate 10 immediately returns to the motor cover 12 side and produces a braking action.
According to the present invention, the amount of descent of a heavy object can be controlled on the order of several millimeters. Note that if the solenoid 14 is operated continuously, the winding drum 2 will rotate at an accelerated rate, so if a circuit is built in that automatically turns off the solenoid 14 every time the winding drum 2 rotates, for example, 1/2 turn. It's safer.

(Effects of the Invention) As is clear from the above description, the present invention provides a solenoid on the motor cover and forcibly slides the brake plate in a de-energized state to release the brake force and lift the winding drum. By allowing the heavy object to gradually rotate under its own weight, it is possible to lower the heavy object very little at a time. Therefore, according to the present invention, there is no need to control the amount of descent of a heavy object by repeatedly rotating the motor in the forward and reverse directions as in the prior art, and the heavy object can be lowered to a desired position in one go. Therefore, the present invention greatly contributes to the industry as an electric hoist that solves the problems of the conventional art.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the main parts of an embodiment of the present invention;
FIG. 2 is a sectional view showing the main parts of a conventional example. 2: Winding drum, 4: Drive shaft, 6: Rotor, 7: Disk, 9: Motor core, 10: Brake plate, 1
1: Spring, 12: Motor cover, 14:
solenoid.

Claims (1)

[Claims] 1 A disc 7 with a rotor 6 facing a motor core 9 fixed to the frame side is slidably attached to the drive shaft 4 of the winding drum 2, and the disc 7
A brake plate 1 is pressed against the inner surface of the motor cover 12 by a spring 11 when the back side is not energized.
This electric hoist is characterized in that a solenoid 14 for forcibly sliding the disk 7 toward the motor core 9 against the spring 11 is mounted on the motor cover 12.