Tools – Wrench – screwdriver – or driver therefor – Handle clutched to head
Reexamination Certificate
2000-03-30
2001-04-03
Smith, James G. (Department: 3723)
Tools
Wrench, screwdriver, or driver therefor
Handle clutched to head
C192S043100
Reexamination Certificate
active
06209423
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a ratchet spanner, more particularly to a ratchet spanner which includes components that can be easily assembled during the manufacturing process thereof and which requires little operating space to operate the same.
2. Description of the Related Art
Referring to
FIGS. 1 and 2
, a conventional ratchet spanner is shown to include a spanner body
1
and a ratchet mechanism. The spanner body
1
has an annular head portion
101
defining a ratchet accommodating chamber
102
with a lower end opening. The ratchet mechanism includes a ratchet wheel
105
disposed rotatably in a front section
103
of the chamber
102
via the lower end opening such that a tool mounting shank
105
″ of the ratchet wheel
105
projects outwardly of the chamber
102
. Two spring-biased pawls
107
and a pawl actuator
106
are disposed in a rear section
104
of the chamber
102
and are operably connected to the ratchet wheel
105
. The pawl actuator
106
can be manually operated in either one of two directions in order to engage a selected one of the pawls
107
with the ratchet wheel
105
such that the conventional ratchet spanner is turnable in only a single direction when in operation.
Some of the drawbacks of the aforementioned conventional ratchet spanner are as follows:
It is somewhat difficult to assemble the components of the aforesaid ratchet spanner. During assembly, after the ratchet wheel
105
, the spring-biased pawls
107
and the pawl actuator
106
are mounted in the chamber
102
, a cover shield
109
is mounted on the spanner body
1
by the use of screws
109
′ to prevent downward removal of the ratchet wheel
105
from the head portion
101
of the spanner body
1
. As such, a relatively long assembly time is incurred.
In addition, because the ratchet wheel
105
has a relatively small number of teeth
105
′ with great pitches, in order to ensure engagement between a rectangular end
107
′ of the pawls
107
and the teeth
105
′ of the ratchet wheel
105
, a large amount of operating space is needed for turning of the spanner body
1
.
Referring to
FIGS. 3 and 4
, another conventional ratchet spanner is shown to include a spanner body
2
and a ratchet mechanism. The spanner body
2
includes an annular head portion
201
which has a peripheral wall
201
A with top and bottom ends and an opening
202
formed through the top and bottom ends, and top and bottom flanges that extend radially and inwardly from the top and bottom ends. The ratchet mechanism includes a ratchet wheel
205
that is disposed rotatably within the opening
202
in the head portion
201
and that defines a tool accommodating cavity at the central portion thereof, a pawl unit
206
disposed within the opening
202
, and a spring unit
207
that is disposed within a retention bore
204
formed in the peripheral wall
201
A and that biases the pawl unit
206
to engage teeth
205
′ of the ratchet wheel
205
.
Because the ratchet wheel
205
is provided with densely located fine profile teeth
205
′, only a small amount of operating space is required to operate the aforesaid conventional spanner. However, during the manufacture of the ratchet wheel
205
, high precision and great skill are needed to produce such type of fine profile teeth
205
′. A high manufacturing cost is thus incurred.
During mass production, a curved recess
203
is firstly formed in the peripheral wall
201
A. The retention bore
204
is then formed by a milling unit and a drilling unit. Since only a small-diameter cutting tool can be used in order to form the retention bore
204
with a relative depth, the cutting tool easily breaks under high speeds of rotation, thereby inconveniencing the operator.
SUMMARY OF THE INVENTION
Therefore, the object of this invention is to provide a ratchet spanner which includes components that are easily manufactured and assembled during the manufacturing process and which requires a relatively small amount of space to operate the same.
Accordingly, a ratchet spanner of the present invention includes a spanner body, a stepped insert member, a vertical cylindrical ratchet wheel, a spring-biased pawl assembly, and a control element. The spanner body has a head portion and a handle, which has an end connected fixedly to the head portion. The head portion has a peripheral wall with a top end and a bottom end, a top flange that extends integrally and inwardly from the top end of the peripheral wall, and a bottom flange that extends integrally and inwardly from the bottom end of the peripheral wall. The top flange defines a top opening therein, and has a curved and slotted inner peripheral surface with an open-ended slot that extends circumferentially therealong. The bottom flange has a circular inner peripheral surface, which is formed with an inward flange that extends integrally, radially and inwardly from a bottom end of the circular inner peripheral surface and that defines a bottom opening therein. The insert member is inserted into the head portion of the spanner body between the top and bottom flanges. The insert member has a lower portion with a top surface, an upper portion that extends integrally and upwardly from the top surface of the lower portion, and a curved shoulder defined between the upper and lower portions. The upper portion of the insert member has a curved side surface, which is formed with an open-ended slot that extends circumferentially therealong and that cooperates with the open-ended slot in the head portion to form an annular slot unit. The upper portion of the insert member extends into the top opening in the head portion of the spanner body. The curved shoulder of the insert member abuts against the top flange of the head portion of the spanner body for preventing upward removal of the insert member from the head portion. The lower portion of the insert member has a side surface with two chamber units and abuts against the bottom flange for preventing downward removal of the insert member from the head portion of the spanner body. The ratchet wheel is disposed rotatably within the head portion of the spanner body. The ratchet wheel has a diameter-reduced bottom end that extends into the bottom opening in the head portion of the spanner body and that defines a circular shoulder, a toothed portion with a plurality of ratchet teeth, and a top end portion that is formed with an annular groove. The circular shoulder of the ratchet wheel abuts against the inward flange of the head portion of the spanner body for preventing downward removal of the ratchet wheel from the head portion of the spanner body. A C-shaped retaining ring is disposed in the head portion of the spanner body in such a manner that the ring engages the annular groove in the ratchet wheel, the open-ended slot in the head portion and the open-ended slot in the insert member for preventing removal of the ratchet wheel and the insert member from the head portion of the spanner body. The pawl assembly includes a first pawl unit and a second pawl unit, which are received respectively within the chamber units in the insert member and which are biased by a spring action to engage the toothed portion of the ratchet wheel. Engagement between the toothed portion of the ratchet wheel and the first pawl unit prevents rotation of the ratchet wheel within the head portion of the spanner body in a first direction. Engagement between the toothed portion of the ratchet wheel and the second pawl unit prevents rotation of the ratchet wheel within the head portion of the spanner body in a second direction that is opposite to the first direction. The control element is mounted operably on the insert member such that the control element presses selectively against one of the first and second pawl units against the spring action, thereby permitting rotation of the ratchet wheel within the head portion of the spanner body in a selected one of the first and second directions.
REFERENCES:
patent: 57944
Sheridan & Ross P.C.
Smith James G.
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