Tools – Wrench – screwdriver – or driver therefor – Having work engaging and force exerting portion inserted...
Reexamination Certificate
1999-04-22
2002-01-29
Meislin, D. S. (Department: 3723)
Tools
Wrench, screwdriver, or driver therefor
Having work engaging and force exerting portion inserted...
C411S404000
Reexamination Certificate
active
06341546
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a screw and a driver bit used for the screw. Especially, the present invention relates to a screw having a bit fitting groove that is suitable for both a Phillips screwdriver and a flat blade screwdriver, and a driver bit used for the screw. More specifically, the present invention relates to a screw having a cross groove formed on the top thereof and a driver bit suitable for the screw, which can engage tightly each other so as to realize quick and secure fastening and loosening by constant and appropriate torque transmission, as well as a header punch for manufacture of screws.
BACKGROUND ART
Conventionally, a general combination of a screw and a driver bit having a configuration shown in
FIGS. 29-32
is known.
FIGS. 29 and 30
show a conventional screw having a cross groove,
FIG. 31
shows a driver bit for the screw having a cross groove, and
FIG. 32
shows a state in which the screw and the driver bit are engaged with each other.
The conventional screw
10
shown in
FIG. 29
has a cross groove
12
on the screw head
10
a.
This cross groove
12
has inclined groove portions
12
a
extending from the edge portion to the center of the neck portion
12
b
and a bottom portion with a substantially conical-shaped bottom surface
14
as a gentle slope. Reference numeral
13
denotes tapered wall portions formed between neighboring cross grooves
12
. This tapered wall portions
13
abut and engage a blade of a driver bit mentioned below. On a corner portion neighboring each of the inclined groove portions
12
a,
a tapered connection surface
17
a
or
17
b
is formed respectively, which extends from the position of the conical-shaped bottom surface
14
to the opening rim portion of the cross groove
12
at the screw head
10
a.
These tapered connection surfaces
17
a
and
17
b
are also adapted to engage a part of the blade of a driver bit mentioned below.
On the other hand, the conventional driver bit
20
shown in
FIG. 31
has blades
22
for engaging the cross groove
12
of the screw
10
and extension blade
22
a
adapted to the contour of the inclined groove portions
12
a
extending from the end edge portion of the cross groove
12
toward the center of the screw neck
12
b.
The reference numeral
23
denotes tapered walls formed on both side surfaces of the blade
22
and the extension blade
22
a.
This tapered wall
23
abuts and engages the tapered wall portions
13
formed on the cross groove
12
of the screw
10
.
The conventional combination of the screw and the driver bit having above-mentioned configuration, as shown in
FIG. 32
, when the screw
10
engages the driver bit
20
, the blades
22
and extension blades
22
a
of the driver bit
20
fit in the inclined groove portions
12
a
of the cross groove
12
, and the side walls
23
of the blades
22
and extension blades
22
a
abut the tapered walls
13
of the cross groove
12
of the screw
10
. Thus, a desired torque is transmitted to the screw
10
by rotating the driver bit
20
. Namely, the screw can be fastened to or loosened from an object.
In addition, a plus-and-minus screw (i.e., a screw with a cross grooved and slotted head)
10
having a configuration shown in
FIGS. 33 and 34
is known, for example, as a screw having a fitting grove that can fit both a Phillips® screwdriver bit and a flat-blade screwdriver bit. As a screwdriver bit that is used for the plus-and-minus screw
10
, the Phillips® screwdriver bit
20
having the configuration shown in
FIG. 31
is used.
FIG. 35
shows a state in which the plus-and-minus screw
10
and the Phillips® screw driver bit
20
engage each other.
The plus-and-minus screw
10
has an advantage in that a conventional flat-blade screwdriver can also be used.
Therefore, the conventional plus-and-minus screw
10
shown in
FIGS. 33 and 34
has a cross groove, i.e., a fitting groove
12
on the screw head
10
a.
This fitting groove
12
consists of a pair of linear grooves
12
a
and
12
b
crossing in the center of the screw head
10
a.
One linear groove
12
a
is adapted to abut and engage the blade of a Phillips® screwdriver, and the other groove
12
b
is adapted to abut and engage the blade of a flat-blade screwdriver.
The linear groove
12
a
includes an inclined groove portions
12
a
extending from the edge rim portion to the center portion of the screw neck
10
b
and the substantially conical-shaped bottom surface
14
formed as a gentle slope at the bottom. Both sides of the inclined groove portions
12
a
is provided with tapered walls
13
a
having a taper toward the bottom. This tapered wall
13
a
abuts and engages the blade of the Phillips screwdriver bit as explained below.
In addition, the other linear groove
12
b
is formed as a horizontal groove (
12
a
) that has a sufficient width and depth for abutting and engaging the blade of the flat-blade screwdriver bit. Both sides of the horizontal groove
12
a
is provided with vertical walls
13
b
that extend substantially vertically toward the bottom. This vertical wall
13
b
abuts and engages the blade of the conventional flat-blade screwdriver bit.
The corner portions between the linear groove (the inclined groove)
12
a
and the other linear groove (the horizontal groove)
12
b
neighboring thereof are provided with tapered connection surfaces
17
a
and
17
b.
A part of the blade of the drive bit mentioned below also abut and engage the tapered connection surfaces
17
a
and
17
b.
Therefore, the conventional Phillips® screwdriver bit
20
shown in
FIG. 31
has a blade
22
that engages the fitting groove
12
of the plus-and-minus screw
10
and am extension blade
22
a
extending so as to fit the contour of the inclined groove portions
12
a
extending from the edge portion of the fitting groove
12
to the center portion of the screw neck
10
b.
The reference numeral
23
denotes the tapered wall portions formed at both side surfaces of the blade
22
and extension blade
22
a.
Namely, this tapered wall portion
23
abuts and engages the tapered wall
13
a
formed on one of the inclined groove portions
12
a
of the fitting groove
12
of the plus-and-minus screw
10
.
According to the combination of the conventional plus-and-minus screw and the Phillips® screwdriver bit, as shown in
FIG. 35
, when the plus-and-minus screw
10
and the Phillips screwdriver bit
20
are engaged with each other, the blades
22
and the extension blade
22
a
of the Phillips® screwdriver bit
20
fit in the fitting groove
12
as mentioned above. One of the pair of the blade
22
and the tapered wall
23
of the extension blade
22
a
abuts the tapered wall
13
a
formed on one of the inclined groove portions
12
a
of the plus-and-minus screw
10
. Thus, when the Phillips® screwdriver bit
20
is rotated, a desired torque is transmitted to the plus-and-minus screw
10
. Namely, the plus-and-minus screw
10
can be fastened to or loosened from an object.
However, according to the combination of the conventional screw (the plus-and-minus screw)
10
and the driver bit (the Phillips® screwdriver bit)
20
, as shown in
FIG. 32
(FIG.
35
), the cross groove
12
of the screw head
10
a
has an inclined groove portions
12
a
extending from the edge portion to the center of the screw neck
10
b.
On the other hand, the corresponding driver bit
20
is adapted so that the edge line portion of the extension blade
22
a
fit to the contour of the inclined groove portions
12
a
to engage the cross groove (the fitting groove)
12
. In addition, the width of the edge line portion of the extension blade
22
a
increases little by little from the front to the rear.
Furthermore, since the tapered wall
23
formed on each blade
22
of the driver bit
20
also abuts and engages the tapered wall
13
formed on the cross groove
12
(the inclined groove portions
12
a
) of the screw (the plus-and-minus screw)
10
, when the driver bit
20
is rotated in a predetermined direction, the contact state of the driver bit
20
with the cross groove
12
(incl
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