Tools – Wrench – screwdriver – or driver therefor – Handle clutched to head
Reexamination Certificate
2002-07-15
2004-06-15
Smith, James G. (Department: 3723)
Tools
Wrench, screwdriver, or driver therefor
Handle clutched to head
C192S04100R
Reexamination Certificate
active
06748825
ABSTRACT:
BACKGROUND OF INVENTION
1. Field of Invention
The present invention relates to a one-way wrench.
2. Related Prior Art
Taiwan Patent Publication No. 281946 teaches a one-way wrench including a head
10
, an annular gear
20
, an engagement block
13
and a spring
14
. The head
10
defines a circular space
11
and a crescent space
111
communicated with the circular space
11
. A wall of the crescent space
111
defines a recess
112
. The annular gear
20
includes an external face formed with a plurality of teeth
23
and an internal face
24
for engagement wit a nut or a head of a bolt. The engagement block
13
includes a convex face formed with a boss
131
and a concave face formed with a plurality of teeth
132
. The spring
14
includes an end receiving the boss
131
. The engagement block
13
and the spring
14
are received in the crescent space
111
. Normally, the teeth
132
are engaged with some of the teeth
23
. The convex face contacts the wall of the crescent space
111
. As the head
10
is rotated in a first direction, the annular gear
20
engaged with the nut or the head of the bolt tends to rotate the engagement block
13
in a second direction opposite to the first direction relative to the head
10
, thus enhancing the contact of the convex face with the wall of the crescent space
111
and the engagement of the teeth
132
with the teeth
23
. Thus, rotation in the first direction of the head
10
relative to the annular gear
20
is avoided. Therefore, the head
10
rotates the annular gear
20
in the first direction together with the nut or the head of the bolt clockwise. When the head
10
is rotated in the second direction, the annular gear
20
engaged with the nut or the head of the bolt is allowed to rotate the engagement block
13
in the first direction relative to the head
10
because the convex face is not hindered by means of the wall of the crescent space
111
. Thus, the teeth
132
can be disengaged from the teeth
23
in order to allow rotation of the head
10
relative to the annular gear
20
. Therefore, rotation of the head
10
in the second direction does not cause rotation of the annular gear
20
in the second direction together with the nut or the head of the bolt.
Taiwan Patent Publication No. 335750 teaches a one-way wrench including a head, an annular gear
35
, an engagement block
40
, a base
50
and a spring
60
. The head defines a crescent space
31
and a circular space
32
and communicated with the crescent space
31
. A wall of the crescent space
31
defines a recess
34
. The annular gear
35
includes an internal face for engagement with a nut or a head of a bolt and an external face formed with a plurality of teeth
52
. The engagement block
40
includes a plurality of teeth and a convex face and defines a recess. The base
50
defines a channel and includes a convex face and a boss
51
formed on the convex face. The spring
60
includes an end received in the recess defined in the engagement block
40
and an opposite end inserted in the channel defined in the base
50
. The engagement block
40
, the base
50
and the spring
60
are received in the crescent space
31
. The boss
51
is received in the recess
34
. The annular gear
35
is received in the circular space
32
. Normally, the teeth of the engagement block
40
are engaged with some of the teeth of the annular gear
35
. The convex faces contact the wall of the crescent space
31
. As the head is rotated in a first direction, the annular gear
35
engaged with the nut or the head of the bolt tends to rotate the engagement block
40
in a second direction opposite to the first direction relative to the head, thus enhancing the contact of the convex face of the engagement block
40
with the wall of the crescent space
31
and the engagement of the teeth of the engagement block
40
with the teeth of the annular gear
35
. Thus, rotation in the first direction of the head relative to the annular gear
35
is avoided. Therefore, the head rotates the annular gear
35
in the first direction together with the nut or the head of the bolt. When the head is rotated in the second direction, the annular gear
35
engaged with the nut or the head of the bolt is allowed to rotate the engagement block
40
in the first direction relative to the head because the convex face of the engagement block
40
is not hindered by means of the wall of the crescent space
31
. Thus, the teeth of the engagement block
40
can be disengaged from the teeth of the annular gear
35
so as to allow rotation of the bead relative to the annular gear
35
. Therefore, rotation of the head in the second direction does not cause rotation of the annular gear
35
in the second direction together with the nut or the head of the bolt. Fabrication and mounting the base
50
require effort and therefore increase its cost.
Taiwan Patent Publication No. 431260 teaches a one-way wrench including a head
20
, an annular gear
50
, an engagement block
30
, a seesaw
40
and a spring
44
. The head
20
defines a circular space
22
and a crescent space
23
communicated with the circular space
22
. The annular gear
50
includes an internal face for engagement with a nut or a head of a bolt and an external face formed with a plurality of teeth
52
. The engagement block
30
includes a plurality of teeth
32
and a convex face
34
and defines a recess
35
. The seesaw
40
includes a convex face
41
, two corners
42
and an end
43
. The spring
44
includes an end fit in the recess
35
and an opposite end in which the end
43
of the seesaw
40
is fit. The engagement block
30
, the seesaw
40
and the spring
44
are movably received in the crescent space
23
. The annular gear
50
is received in the circular space
22
. When the head
20
is rotated in a first direction, the annular gear
50
contacts one of the corners
42
, thus pivoting the engagement block
30
to the annular gear
50
. Thus, the teeth
32
are engaged with some of the teeth
52
so that the annular gear
50
engaged with the nut or the head of the bolt tends to rotate the engagement block
30
in a second direction opposite to the first direction relative to the head
10
, thus enhancing the contact of the convex face
34
with the wall
24
and the engagement of the teeth
32
with the teeth
52
. Therefore, rotation in the first direction of the head
20
relative to the annular gear
50
is avoided. The head
20
rotates the annular gear
50
in the first direction together with the nut or the head of the bolt. When the head
20
is rotated in the second direction, the annular gear
50
contacts both the corners
42
so as to pivot the engagement block
30
from the annular gear
50
. Thus, the teeth
32
are disengaged from the teeth
52
so as to allow rotation of the head
20
relative to the annular gear
50
. Therefore, rotation of the head
20
in the second direction does not cause rotation of the annular gear
50
in the second direction together with the nut or the head of the bolt. The engagement block
30
may not be engaged with or disengaged from the annular gear
50
as desired since the engagement block
30
, the seesaw
40
and the spring
44
can slide together in the crescent space
23
. Moreover, fabrication and installment of the seesaw
40
requires effort and therefore increase its cost.
The present invention is therefore intended to obviate or at least alleviate the problems encountered in prior art.
SUMMARY OF INVENTION
It is the primary objective of the present invention to provide a one-way wrench that is simple in structure and low in cost.
According to the present invention, a one-way wrench includes a head, a gear, an engagement element and a bent spring. The head defines a circular space and a crescent space communicated with the circular space. The gear includes a plurality of teeth, and is received in the circular space. The engagement element includes a concave face formed with a plurality of teeth and a convex face, and is received in the crescent space. The teeth o
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