Tools – Wrench – screwdriver – or driver therefor – Spanner
Reexamination Certificate
2002-08-09
2004-06-29
Smith, James G. (Department: 3723)
Tools
Wrench, screwdriver, or driver therefor
Spanner
C081S451000, C081S176150
Reexamination Certificate
active
06755099
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a drive wrench structure, and more particularly to a drive wrench structure that may co-operate with a drive disk to screw a piston into a wheel cylinder or unscrewing the piston from the wheel cylinder, wherein the guide rod of the drive handle may protrude outward from the through hole of the mounting stud when in use, and may be retracted into and fully hidden in the through hole of the mounting stud when not in use, thereby protecting the guide rod of the drive handle, and thereby facilitating storage of the drive wrench structure.
2. Description of the Related Art
In general, the brake system of the automobile includes a brake pedal for operating a brake cylinder which may transmit the hydraulic oil into each wheel cylinder to push the piston in each wheel cylinder, so that the piston may push the brake lining to rub the brake disc, thereby achieving the braking purpose. When the piston is worn out, a drive wrench may be used to assemble and disassemble the piston of the wheel cylinder.
A conventional drive wrench
5
in accordance with the prior art shown in
FIG. 5
has an end portion provided with a square drive head
50
that may be inserted into a square mounting hole
60
of a drive disk
6
for rotating the drive disk
6
. The drive disk
6
has a periphery provided with an outer flange
61
mounted on the periphery of an end face of the piston
7
, the drive disk
6
is provided with an insertion stub
62
that may be inserted into one of multiple insertion recesses
70
formed in the piston
7
, for rotating the piston
7
, so that the piston
7
may be screwed into the wheel cylinder, and may be unscrewed from the wheel cylinder.
However, the outer flange
61
of the drive disk
6
has a fixed diameter to fit the piston of a fixed size, so that it is necessary to change the drive disk
6
to fit pistons of different sizes, thereby causing inconvenience in use and operation. In addition, the outer flange
61
of the drive disk
6
is mounted on the periphery of the piston
7
, so that the driven force arm is longer, thereby wasting the manual work in operation. Further, the outer flange
61
is protruded from the drive disk
6
, so that it is easily broken due to hit by a foreign object.
As shown in
FIG. 6
, the drive disk
6
a
has a center provided with an inner flange
60
a
that may be inserted into a depression
71
formed in the center of the outer end face of the piston
7
. In operation, when the drive wrench
5
is rotated, the insertion stub
61
a
may be rotated about the inner flange
60
a
to push the insertion recess
70
for rotating the piston
7
, so that the piston
7
may be screwed into the wheel cylinder, and may be unscrewed from the wheel cylinder. Thus, the driven force arm between the inner flange
60
a
and the insertion stub
61
a
may be shortened, thereby saving the manual work. However, the inner flange
60
a
is protruded from the drive disk
6
a
, so that it is easily broken due to hit by a foreign object. In addition, the inner flange
60
a
is easily detach from the depression
71
, thereby causing inconvenience in operation.
SUMMARY OF THE INVENTION
The present invention has arisen to mitigate and/or obviate the disadvantage of the conventional drive wrench.
The primary objective of the present invention is to provide a drive wrench structure, wherein the guide rod of the drive handle may protrude outward from the through hole of the mounting stud when in use, and may be retracted into and fully hidden in the through hole of the mounting stud when not in use, thereby protecting the guide rod of the drive handle, and thereby facilitating storage of the drive wrench structure.
In accordance with the present invention, there is provided a drive wrench structure, comprising:
a drive handle having one end provided with a threaded rod, the threaded rod having a distal end provided with a guide rod; and
a mounting stud having a first side formed with a screw bore screwed on the threaded rod of the drive handle, and a second side formed with a through hole for passage of the guide rod of the drive handle, with the guide rod of the drive handle protruding outward from the through hole of the mounting stud.
REFERENCES:
patent: 1298324 (1919-03-01), Funk
patent: 4569259 (1986-02-01), Rubin et al.
patent: 5003681 (1991-04-01), Schley
patent: 5182973 (1993-02-01), Martindell
patent: 6095017 (2000-08-01), Long
LandOfFree
Drive wrench structure does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Drive wrench structure, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Drive wrench structure will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3350677