Tools – Wrench – screwdriver – or driver therefor – Handle clutched to head
Reexamination Certificate
2002-09-26
2004-08-24
Meislin, Debra S. (Department: 3723)
Tools
Wrench, screwdriver, or driver therefor
Handle clutched to head
C081S063000, C081S063200
Reexamination Certificate
active
06779422
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a ratchet wrench that may prevent jamming during operation, and more particularly to a ratchet wrench that may prevent jamming during operation, wherein when the ratchet wrench jams during operation, the jamming prevention portion may force the pawl member to detach from the ratchet wheel, thereby preventing the ratchet wrench from jamming during operation.
2. Description of the Related Art
A conventional ratchet wrench in accordance with the prior art comprises a wrench body having one end provided with a drive head formed with a receiving chamber, a ratchet wheel rotatably mounted in the receiving chamber of the drive head of the wrench body, a pawl member pivotally mounted in the receiving chamber of the drive head of the wrench body and meshing with the ratchet wheel, and an elastic member mounted in the receiving chamber of the drive head of the wrench body and urged on the pawl member.
In operation, when the drive head of the wrench body is rotated in the operation direction (such as in the counterclockwise direction), the pawl member are closely engaged with the ratchet wheel, so that the workpiece may be rotated counterclockwise by the ratchet wheel. On the contrary, when the drive head of the wrench body is rotated in the reverse direction (such as in the clockwise direction), the ratchet wheel forces the pawl member to compress the elastic member, so that the ratchet wheel are disengaged from the pawl member, and so that the drive head of the wrench body idles.
However, when the ratchet wheel jams with the pawl member during the idling process of the ratchet wrench, the pawl member compresses the elastic member successively, so that the elastic member is easily distorted or worn out.
SUMMARY OF THE INVENTION
The present invention has arisen to mitigate and/or obviate the disadvantage of the conventional ratchet wrench.
The primary objective of the present invention is to provide a ratchet wrench that may prevent jamming during operation, wherein when the pawl member jams with the ratchet wheel, the jamming prevention portion of the pawl member is rested on the wall of the locking recess of the drive head of the wrench body, so that the pawl member is forced to detach from the ratchet wheel, and the ratchet wheel is detached from the drive head of the wrench body, thereby achieving the purpose of preventing the ratchet wrench from jamming during operation.
Another objective of the present invention is to provide a ratchet wrench that may prevent jamming during operation, wherein when the pawl member compresses the elastic member to a determined extent, the jamming prevention portion of the pawl member applies a reaction on the wall of the locking recess of the drive head of the wrench body, so that the pawl member will not compress the elastic member to an excessive extent, thereby preventing from wearing the elastic member.
In accordance with the present invention, there is provided a ratchet wrench that may prevent jamming during operation, comprising a wrench body, a ratchet wheel, a pawl member, and an elastic member, wherein:
the wrench body has one end provided with a drive head, the drive head of the wrench body is formed with a receiving chamber and a locking recess located beside and communicated with the receiving chamber, the locking recess of the drive head of the wrench body has a wall having a first side and a second side;
the ratchet wheel is rotatably mounted in the receiving chamber of the drive head of the wrench body and has an outer wall provided with a plurality of ratchet teeth;
the pawl member is pivotally mounted in the locking recess of the drive head of the wrench, body, and has a first end provided with an urging portion rested on the second side of the wall of the locking recess of the drive head of the wrench body,
the pawl member has a first side provided with a plurality of engaging teeth meshing with the ratchet teeth of the ratchet wheel and a second side provided with a protruding jamming prevention portion rested on the wall of the locking recess of the drive head of the wrench body; and
the elastic member is mounted in the locking recess of the drive head of the wrench body, and has a first end secured on the second end of the pawl member and a second end secured on the first side of the wall of the locking recess of the drive head of the wrench body.
Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings.
REFERENCES:
patent: 6446530 (2002-09-01), Chang
patent: 2002/0162424 (2002-11-01), Hu
patent: 2003/0019335 (2003-01-01), Hu
Meislin Debra S.
Rosenberg , Klein & Lee
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