Reversible ratchet wrench with high torsion

Details Reversible ratchet wrench with high torsion Reversible ratchet wrench with high torsion

2001-06-21

2003-10-07

Hail, III, Joseph J. (Department: 3723)

Tools

Wrench, screwdriver, or driver therefor

Handle clutched to head

C081S063000

Reexamination Certificate

active

06629477

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a reversible ratchet wrench, and more particularly to a reversible ratchet wrench with a high torsion.
2. Description of the Related Art
A conventional reversible ratchet wrench
80
in accordance with the prior art shown in
FIG. 12
comprises a handle
81
having an enlarged driving head
82
defining a driving chamber
83
and a retaining recess
84
connecting to the driving chamber
83
, a driving member
86
secured in the driving chamber
83
, a direction change device “B” including a retaining member
21
pivotally mounted on a pivot axle
20
and including a tooth-shaped retaining portion
210
meshing with the driving member
86
, a pressing device “C” including a pressing member
23
urged on the positioning protrusion
211
of the retaining member
21
, and a spring
24
biased between the pressing member
23
and the handle
81
.
However, the conventional reversible ratchet wrench in accordance with the prior art has the following disadvantages.
1. The retaining member
21
is engaged with the driving member
86
so that the force exerted on the retaining member
21
is directly transmitted to the pivot axle
20
. Therefore, when the driving member
86
is used to drive and operate a workpiece, the force is entirely concentrated on the pivot axle
20
so that the pivot axle
20
is easily worn out, thereby shortening the lifetime of the ratchet wrench.
2. The locking force exerted by the retaining member
21
on the driving member
86
is supplied by the pivot axle which can only afford a limited locking force so that when the driving member
86
is used to drive a large workpiece, the retaining member
21
cannot efficiently lock and retain the driving member
86
so that the driving member
86
easily slips on the retaining member
21
, thereby causing the ratchet wrench inoperative.
3. When the user wishes to change the driving direction of the ratchet wrench, the retaining member
21
is rotated about the pivot axle
20
to move the positioning protrusion
211
which then presses the pressing member
23
inward so that the positioning protrusion
211
can be moved to and located on the other side of the pressing member
23
. In such a manner, the positioning protrusion
211
is frequently engaged with the pressing member
23
, thereby greatly increasing the friction therebetween so that the positioning protrusion
211
is easily worn out during long-term utilization.
SUMMARY OF THE INVENTION
In accordance with an embodiment of the present invention, there is provided a reversible ratchet wrench comprising: a handle having an enlarged driving head defining a driving chamber therein, a receiving chamber defined in the handle and located adjacent to the driving chamber, a retaining recess defined in a side wall of the driving chamber and connecting to the receiving chamber; a driving member secured in the driving chamber and having an outer wall provided with a plurality of tooth-shaped first retaining portions; and a direction control device mounted on the handle.
The direction control device includes: a direction control member rotatably mounted in the receiving chamber; a retaining member pivotally mounted in the retaining recess and having a first side provided with a plurality of tooth-shaped second retaining portions meshing with the plurality of tooth-shaped first retaining portions; a pressing member mounted between the receiving chamber and the retaining recess, the pressing member being secured on the direction control member to rotate therewith and slidably rested on a second side of the retaining member for pivoting the retaining member; and an elastic member mounted between the direction control member and the pressing member for urging the pressing member on the second side of the retaining member.
In accordance with another embodiment of the present invention, each of the second retaining portions of the retaining member has two sides each formed with a convex arcuate edge and a mediate section located between the two sides and formed with a locking edge.
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: 4336728 (1982-06-01), Deibert
patent: 6044731 (2000-04-01), Hsieh
patent: 6161454 (2000-12-01), Chaconas
patent: 6230591 (2001-05-01), Ling et al.
patent: 6282991 (2001-09-01), Hu
patent: 6282992 (2001-09-01), Hu
patent: 6301998 (2001-10-01), Hu
patent: 6308594 (2001-10-01), Cheng
Hu, Bobby, “Positioning Device for a Switch Member of a Reversible Ratchet-Type Wrench”, Nov. 1, 2001, Pub. No. 2001/0035074 A1, entire document.

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