Tools – Wrench – screwdriver – or driver therefor – Handle clutched to head
Reexamination Certificate
2001-03-21
2002-05-14
Smith, James G. (Department: 3723)
Tools
Wrench, screwdriver, or driver therefor
Handle clutched to head
C192S043200
Reexamination Certificate
active
06386072
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a ratchet tool having a pawl member with a curve surface which is matched with a recess in the head of the tool so as to provide a strong backup when outputting a large torque.
BACKGROUND OF THE INVENTION
A conventional ratchet tool is shown in FIG.
1
and generally includes a head
1
with a ring member
2
rotatably received in a space
10
of the head
1
. A toothed outer periphery
20
of the ring member
2
is engaged with a pawl member
3
which has a protrusion biased by a ball
13
urged by a spring
12
. The pawl
3
has two tip ends and each of which has two teeth
30
for engaging with the toothed outer periphery
20
of the ring member
2
. A lever
35
is connected to the pawl
3
to choose which tip end is engaged with the ring member
2
. However, only two teeth
30
engaged with the toothed periphery
20
of the ring member
2
cannot provide enough backup for the ratchet mechanism. In other words, the engagement between the two teeth
30
and the ring member
2
cannot output a large torque and this restrains the use of the ratchet tool.
SUMMARY OF THE INVENTION
In accordance with one aspect of the present invention, there is provided a ratchet tool and comprising a ring-shaped head having a recess defined in an inner periphery thereof. A first passage is defined in a curve surface defining the recess so as to receive a first ball and a first spring. A ring member is rotatably received in the ring-shaped head and has a toothed outer periphery and a serrated inner periphery. A pawl is movably received in the recess and has a toothed surface. A protrusion extends from a top of the pawl. A plate has a notch for retaining the protrusion therein and two rods extend from the plate. A positioning ring is engaged with the ring-shaped head and has a slot through which the two rods extend. A lever has a head which has two holes so as to receive the two rods of the plate.
The primary object of the present invention is to provide a ratchet tool that has a larger contact area between the pawl member and the ring member.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, several embodiments in accordance with the present invention.
REFERENCES:
patent: 3269496 (1966-08-01), Kilness
patent: 6282993 (2001-09-01), Forman et al.
Pei-Chih Yang
Yuan-Chin Chi
Baxley Charles E.
Smith James G.
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