JPH1179687A - Electric chain block - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lift a hook in a high position and improve durability of a rotary shaft or the like of a limit switch by forming a recessed groove which an operating plate can enter when a top part of a hook comes in contact with the outer side face of a housing, on the outer side face of the housing and forming a clearance between a bottom surface of the recessed groove and the operating plate. SOLUTION: A recessed groove which an operating plate 11 can enter is formed on a flat lower side face of a block 9. When chain winding action is performed and a top part 12 of a hook 5 reaches the vicinity of the lower side face of the block 9, the top part 12 of the hook 5 comes in contact with the operating plate 11 so as to be moved upward to enter the recessed groove 13. A limit switch is actuated immediately before the top part 12 of the hook 5 comes in contact with the lower side face of the block 9, and the whole operating plate 11 enters the recessed groove 13 when the top part 12 of the hook 5 comes in contact with the lower side face of the block 9. At this time, a clearance is formed between the bottom face of the recessed groove 13 and the operating plate 11, so that the operating plate 11 is not held tight between the top part 12 of the hook 5 and the bottom face of the recessed groove 13.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to an electric chain block.

[0002]

2. Description of the Related Art In an electric chain block in which a hook is attached to a tip of a chain extending downward from a housing body, it is preferable that the hook can be raised to a position as high as possible when the chain is wound. For this purpose, it is preferable to stop the hoisting action of the chain when the top of the hook comes into contact with the lower surface of the housing.

In order to stop the hoisting action of the chain, it is necessary to stop the hoisting electric motor. For this purpose, it is necessary to detect that the top of the hook has contacted the lower surface of the housing. In order to perform such detection, a limit switch operation plate is conventionally mounted on the rotation shaft of the limit switch, and the operation plate is usually attached to the outside of the housing after the top of the hook reaches the vicinity of the outer surface of the housing during the winding operation of the chain. Until contact with the side surface, it is arranged so as to be moved toward the outer surface of the housing together with the top of the hook while being in contact with the top of the hook.

[0004]

When the operating plate is arranged in this manner, the top of the hook comes into contact with the lower surface of the housing via the operating plate, and at this time the limit switch is operated. The hoisting electric motor is stopped. However, if the top of the hook abuts on the lower surface of the housing via the operating plate in this way, that is, if the operating plate is strongly sandwiched between the top of the hook and the lower surface of the housing, the rotating shaft of the operating plate and the limit switch will be excessively moved. There is a problem that high stress is applied and thus their durability is impaired.

[0005]

According to the present invention, a hook is attached to a tip of a chain extending outward from a housing body, and when the chain is wound, the top of the hook is attached to the housing. In an electric chain block in which the winding operation of the chain is stopped by abutting on the outer surface, during the winding operation of the chain, after the top of the hook reaches the vicinity of the outer surface of the housing and until it contacts the outer surface of the housing, the hook of the hook is moved. An operating plate of a limit switch which is moved toward the housing outer surface together with the top of the hook while being in contact with the top,
A concave groove is formed on the outer surface of the housing where the operating plate can enter when the top of the hook contacts the outer surface of the housing, and a gap is formed between the bottom surface of the concave groove and the operating plate. . That is, the pinching action is not generated on the operation plate.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS.
Is an electric chain block, 2 is a housing, 3 is a hook for suspending the electric chain block, 4 is a chain extending downward from the housing 2, 5 is a hook attached to the lower end of the chain 4, 6 is a limit switch , 7
Indicates rotation shafts connected to the limit switch 6, respectively.
A U-shaped recess 8 is formed on the lower side of the housing 2, and a block 9 constituting a part of the housing 2 is attached to the center of the recess 8. The rotating shaft 7 extends through the block 9 and is rotatably supported by the block 9.

Arms 10 fixed to the rotating shaft 7 and extending obliquely upward from the rotating shaft 7 are arranged on both sides of the block 9, and the distal ends of the arms 10 are bridged by an operating plate 11. The operation plate 11 is disposed above the top 12 of the hook 5 so as to be able to contact the top 12 of the hook 5.
In addition, a concave groove 13 into which the operation plate 11 can enter is formed on the flat lower side surface of the block 9 located above the operation plate 11. The groove 13 has a depth greater than the thickness of the operation plate 11.

[0008] The operating plate 11 is usually located at a position where it comes out of the groove 13 downward as shown in FIG. Chain 4
When the top portion 12 of the hook 5 reaches the vicinity of the lower surface of the block 9, the top portion 12 of the hook 5 comes into contact with the operation plate 11. Next, the operating plate 11 is moved upward while being in contact with the top 12 of the hook 5, and then the operating plate 11 enters into the concave groove 13. Then the top 1 of the hook 5
Immediately before the block 2 comes into contact with the lower surface of the block 9, the limit switch 6 is operated, whereby a drive stop signal is given to the electric motor for winding. Next, the top 12 of the hook 5 abuts against the lower surface of the block 9, and this time,
Is shown in

[0009] As shown in FIG.
When the plate comes into contact with the lower surface of the block 9, the entire operation plate 11 enters the groove 13. At this time, a gap is formed between the bottom surface of the concave groove 13 and the operation plate 11. Therefore, the operating plate 11 is not pinched between the top 12 of the hook 5 and the bottom of the concave groove 13, and thus the arm 10 and the rotating shaft 7
No excessive stress is generated. Therefore, the durability of the rotating shaft 7 and the like can be improved.

[0010]

According to the present invention, the durability of the rotary shaft of the limit switch can be improved while the hook can be raised to a position as high as possible.

[Brief description of the drawings]

FIG. 1 is a side view of an electric chain block.

FIG. 2 is a front view of the electric chain block.

FIG. 3 is a partially enlarged view of FIG. 1;

[Explanation of symbols]

 2 ... housing 3, 5 ... hook 4 ... chain 11 ... operating plate 13 ... groove

Claims (1)

[Claims] 1. An electric chain in which a hook is attached to a tip end of a chain extending outward from a housing main body, and when the chain is wound up, a top portion of the hook comes into contact with an outer surface of the housing, thereby stopping the winding operation of the chain. In the block, during the winding operation of the chain, until the top of the hook reaches the vicinity of the outer surface of the housing and then contacts the outer surface of the housing, the hook is moved toward the outer surface of the housing together with the top of the hook while contacting the top of the hook. An operating plate of a limit switch to be provided, and a concave groove is formed on the outer surface of the housing where the operating plate can enter when the top of the hook comes into contact with the outer surface of the housing. An electric chain block in which a gap is formed between operating plates.