Tools – Wrench – screwdriver – or driver therefor – Handle clutched to head
Reexamination Certificate
1999-02-11
2001-03-20
Scherbel, David A. (Department: 3723)
Tools
Wrench, screwdriver, or driver therefor
Handle clutched to head
C081S177400
Reexamination Certificate
active
06202512
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a screwdriver, more particularly to a multi-purpose screwdriver that is convenient to use.
2. Description of the Related Art
A conventional screwdriver generally has a handle. One end of the handle is provided with a tool bit for driving a screw. In use, as the space in which the screwdriver works is often small and narrow, the user does not have enough room to manipulate the screwdriver smoothly. This need resulted in the development of a torsion screwdriver that can be turned in a single direction. Referring to
FIG. 1
, a conventional torsion screwdriver
1
is shown to include a hollow handle
11
, a positioning sleeve
12
provided in the handle
11
, a locking tube
13
received in the positioning sleeve
12
, a plurality of locking cylinder rods
14
provided between the positioning sleeve
12
and the locking tube
13
, a curved spring strip
15
provided on the locking tube
13
, a rotary member
16
connected to the locking tube
13
, and a bit-driving shaft
17
that can pass through all of the rotary member
16
, the locking tube
13
, and the positioning sleeve
12
. The handle
11
has a hollow interior defining a receiving space
111
with a substantially square-shaped cross-section. One end of the handle
11
is closed by a screw cap
113
. A packing ring
112
is used to ensure the closure effect. The positioning sleeve
12
has a front end provided with an inward projection
122
, and a rear end formed with a through hole
121
for extension of a first end of the bit-driving shaft
17
. There is further provided a retaining ring
18
on an outer side of the through hole
121
to secure the bit-driving shaft
17
onto the positioning sleeve
12
. Furthermore, the locking tube
13
is generally cylindrical, and has a front end provided with an annular outward flange
133
. The above-mentioned curved spring strip
15
and the rotary member
16
are positioned on the annular outward flange
133
of the locking tube
13
. The curved spring strip
15
has a first end passing through the annular outward flange
133
of the locking tube
13
to be retained by the inward projection
122
of the positioning sleeve
12
. The locking tube
13
further has an axially extending positioning hole
131
, and a plurality of axially extending rod-retaining slots
132
for receiving the locking cylinder rods
14
. The rod-retaining slots
132
are communicated with the positioning hole
131
. In addition, the bit-driving shaft
17
has a second end provided with a tool bit receiving hole adapted to receive a tool bit
171
.
Reference is made to
FIG. 2
, which shows the screwdriver
1
in a state of use. With cross-reference to
FIG. 1
, when the handle
11
is turned in a certain direction, the positioning sleeve
12
forces the locking cylinder rods
14
to abut against a peripheral surface of the bit-driving shaft
17
, thereby bringing the bit-driving shaft
17
to turn with the handle
11
. When the handle
11
is turned in a reverse direction, the positioning sleeve
12
ceases to force the locking cylinder rods
14
against the peripheral surface of the bit-driving shaft
17
so that the bit-driving shaft
17
does not turn with the handle
11
. The intended object of unidirectional rotation can therefore be achieved. However, since the bit-driving shaft
17
always has the peripheral surface thereof in contact with the locking cylinder rods
14
regardless of its turning direction, it cannot be independently detached from the screwdriver
1
. This is because removal of the bit-driving shaft
17
from the locking tube
13
will cause the locking cylinder rods
14
to fall into the positioning hole
131
of the locking tube
13
. If the user intends to change the tool bit
171
at the second end of the bit-driving shaft
17
with another one (not shown) pre-disposed in the receiving space
111
of the handle
11
, the user has to remove the screw cap
113
and the packing ring
112
in order to have access to the tool bit in the receiving space
111
. After installing the new tool bit, the user has to put the previous tool bit in the receiving space
111
, and then put the packing ring
112
and the screw cap
113
back into position. It can be seen that the conventional screwdriver
1
is very troublesome and inconvenient to use. In addition, the tool bit receiving hole of the bit-driving shaft
17
is adapted for use with tool bits of a single size only, thereby limiting the utility of the conventional screwdriver
1
.
SUMMARY OF THE INVENTION
Therefore, the main object of the present invention is to provide a torsion screwdriver that has multi-purposes and that is convenient to use.
Another object of the present invention is to provide a torsion screwdriver that allows easy replacement of tool bits.
Accordingly, a torsion screwdriver of the present invention comprises a positioning sleeve, a locking tube, a plurality of locking cylinder rods, a curved spring strip, a rotary member, a coupling sleeve, and a bit-driving shaft. The positioning sleeve is formed with an axially extending locking hole that is defined by a plurality of adjacent locking sides interconnected by adjoining corners. The positioning sleeve has a tubular part that is formed with the locking hole, a radial outward flange that is disposed on a front end of the tubular part, and an annular skirt that extends forwardly from an outer periphery of the radial outward flange. The annular skirt is formed with an inward projection. The locking tube is disposed in the positioning sleeve, and is formed with an axial sleeve-receiving hole and a plurality of axially extending rod-retaining slots communicated with the sleeve-receiving hole. The locking tube has a front end formed with an annular outward flange that is confined by the annular skirt. The locking cylinder rods are received in the rod-retaining slots, respectively. The curved spring strip has a first end connected to the annular outward flange of the locking tube, and a second end abutting against the inward projection on the annular skirt of the positioning sleeve. The rotary member is disposed adjacent to the front end of the locking tube, and is coupled to the annular outward flange of the locking tube for co-rotation therewith. The rotary member is formed with a through hole aligned with the sleeve-receiving hole of the locking tube. The coupling sleeve is disposed in the sleeve-receiving hole of the locking tube, and is in contact with the locking cylinder rods. Rotation of the positioning sleeve in a first direction results in engagement of the locking cylinder rods with the locking sides to permit co-rotation of the coupling sleeve with the positioning sleeve. Rotation of the positioning sleeve in a second direction results in alignment of the locking cylinder rods with the adjoining corners to disengage the locking cylinder rods from the locking sides and result in idle rotation of the positioning sleeve relative to the coupling sleeve. The coupling sleeve is formed with an axially extending coupling hole, and has a front end portion that extends into the through hole in the rotary member and that is retained rotatably on the rotary member. The bit-driving shaft extends into the coupling hole in the coupling sleeve. One of the bit-driving shaft and the coupling sleeve is formed with a radial key projection. The other one of the bit-driving shaft and the coupling sleeve is formed with an axially extending keyway that engages slidably the key projection to couple removably and non-rotatably the bit-driving shaft and the coupling sleeve.
REFERENCES:
patent: 4341292 (1982-07-01), Acevedo
patent: 4448097 (1984-05-01), Rocca
patent: 5406866 (1995-04-01), Badiali
patent: 5651294 (1997-07-01), Shiao
patent: 5819612 (1998-10-01), Anderson
patent: 5894765 (1999-04-01), Anderson et al.
patent: 5904080 (1999-05-01), Anderson et al.
patent: 5943921 (1999-08-01), Lin
O'Brien Daniel J.
Wu Chih-Ming
Jacobson Price Holman & Stern PLLC
Scherbel David A.
Thomas David B.
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