Tools – Wrench – screwdriver – or driver therefor – Machine
Reexamination Certificate
1999-09-27
2001-04-03
Scherbel, David A. (Department: 3723)
Tools
Wrench, screwdriver, or driver therefor
Machine
C081S062000
Reexamination Certificate
active
06209422
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an improvement in a ratchet wrench used for tightening and loosening bolts and nuts in assembly and disassembly of automobiles, industrial machines and so on.
BACKGROUND OF THE INVENTION
An electrical or hand-operated ratchet wrench has been heretofore used for positively and quickly tightening or removing bolts, nuts or the like. A conventional ratchet wrench is disclosed in U.S. Pat. No. 5,537,899 and the main structure thereof will be explained hereinafter with reference to FIGS. 12 to 19.
As shown in
FIG. 12
, a housing
10
is internally provided with a motor
12
, a conventional motion conversion means
14
for changing rotational speed of the motor
12
, and a crank shaft
16
which is mounted for rotational motion and reciprocating sliding motion by the motion conversion means
14
.
As shown in
FIG. 13
, the crank shaft
16
is integrally formed at the extreme end thereof with a core
18
which is eccentric from the center of the shaft and parallel with the center of the shaft, and a bushing
22
having an insert hole
20
is slidably mounted on the core
18
. As shown in
FIGS. 12 and 14
, the housing
10
is integrally formed at the extreme end thereof with a pair of annular holding portions
24
, and an oscillating member
26
shown in
FIG. 13
is provided between the pair of annular holding portions
24
. The oscillating member
26
is formed in the center thereof with a hole
28
, and the hole
28
is formed in the inner wall thereof with an internal gear
30
. The oscillating member
26
has a pair of arms
32
at the extreme end thereof, and a space
34
is formed between the pair of arms
32
. The bushing
22
is rotatably and undisengageably fitted into the space
34
.
As shown in
FIG. 15
, a shank
36
for intermittently rotating bolts or the like comprises a columnar base portion
38
and a cubical engaging portion
40
formed integral with the base portion
38
. The base portion
38
of the shank
36
is inserted into the hole
28
of the oscillating member
26
. The oscillating member
26
with the shank
36
mounted therein is held between the pair of annular holding portions
24
of the housing
10
shown in
FIGS. 12 and 14
. As the crank shaft
16
rotates, the oscillating member
26
oscillates about the center axis of the hole
28
.
In the shank
36
, the columnar base portion
38
is internally provided with two wing members
44
which are oscillatable about a pin
42
. Each wing member
44
is formed on both left and right ends thereof with a plurality of pawls
46
. The columnar base portion
38
is formed with a central axial hole
48
, and a columnar switching member
52
(
FIG. 16
) integrally formed with a switching knob
50
is fitted into the hole
48
. The switching member
52
is mounted for rotation through a given angular range relative to the shank
36
.
As shown in
FIGS. 16 and 17
, the switching member
52
is formed with two axially extending holes
54
with openings opposite each other by 180 degrees. Each hole
54
is internally provided with a tubular bushing pin
56
with one end closed, and one end open to receive a spring
58
internally to bias the bushing pin
56
outwardly from the switching member
52
. As shown in
FIG. 17
, the closed end of the bushing pin
56
is biased by the spring
58
so as to project from the hole
54
into contact with the wing member
44
, thereby pressing against the wing member
44
.
The switching member
52
is normally and reversely rotated, for example, by approximately 90 degrees, when fitted into the hole
48
of the base portion
38
of the shank
36
, by turning the switching knob
50
of the switching member
52
, and the switching member
52
maintains one of the two stable positions shown in
FIGS. 18 and 19
. In
FIGS. 18 and 19
, each wing member
44
is pressed by the bushing pin
56
and the spring
58
so that the pawl
46
on one of left and right sides of each wing member
46
is engaged with the internal gear
30
of the oscillating member
26
. In
FIG. 18
, the bushing pin
56
presses one side of the wing member
44
which oscillates about the pin
42
. The part of the wing member
44
pressed by the bushing pin
56
is shifted from one side to the other of the wing member
44
by turning the switching knob
50
from the position shown in
FIG. 18
to that of FIG.
19
. By the switching with the switching knob
50
, the pawl
46
of each wing member
44
meshed with the internal gear
30
of the oscillating member
26
is switched from one side to the other, thus switching between tightening rotation and loosening rotation.
When the oscillating member
26
is rotated in one direction with one pawl
46
of each wing member
44
engaged with the internal gear
30
of the oscillating member
26
, wing members
44
move together with the oscillating member
26
. On the other hand, when the oscillating member
26
is rotated in an opposite direction, the pawl
46
of each wing member
44
and the internal gear
30
of the oscillating member
26
come in contact but slip so that they are not engaged, and the wing members
44
will not move together with the oscillating member
26
.
Thus, as shown in
FIG. 18
, when the oscillating member
26
is rotated in direction A, a tightening operation results, and when the oscillating member
26
is rotated in direction B slip occurs. In this manner, the tightening is carried out by repeating the tightening operation and the slip operation. Further, when switched from the
FIG. 18
state to the
FIG. 19
state, and when the oscillating member
26
is rotated in a direction C, the loosening operation results, and when the oscillating member
26
is rotated in a direction D, slip occurs.
As shown in
FIGS. 12 and 14
, the engaging portion
40
of the shank
36
is generally cubical in shape, and the engaging portion
40
projects, beyond one annular supporting portion
24
at the distal end of the housing
10
, in a direction perpendicular to the length of the housing
14
. A socket
60
for transmitting the intermittent rotational force of the ratchet wrench to the bolt or the like is detachably mounted on the engaging portion
40
of the shank
36
. The socket
60
is cylindrical, and one end thereof is provided with a first hole
62
which is square in section for mating with the engaging portion
40
of the shank
36
, and the other end thereof is provided with a second hole
64
which is hexagonal in section for fitting over a bolt (not shown). When the ratchet wrench is used, the socket
60
is mounted between the engaging portion
40
of the shank
36
and the bolt for tightening or loosening the bolt.
The operation of the ratchet wrench constructed as described above will be explained below.
First, when the motor
12
shown in
FIG. 12
is driven, the crank shaft
16
is rotated through the known motion conversion means
14
. When the crank shaft
16
is rotated, the core
18
of the crank shaft
16
causes the bushing
22
to rotate in a planetary orbit about the center axis the crank shaft
16
. The planetary motion of the bushing
22
causes the oscillating member
26
to oscillate about the center axis of the columnar base portion
38
of the shank
36
.
When the oscillating member
26
is oscillated in one direction, the pawl
46
on one side of the wing member
44
mounted on the shank
36
projects and is meshed with the internal gear
30
of the oscillating member
26
to rotate the shank
36
to tighten the bolt or the like (in direction A in FIG.
18
). When the oscillating member
26
is oscillated in the opposite direction (B in FIG.
18
), the projecting pawl
46
does not mesh with the internal gear
30
and the shank
36
is not rotated. Thereafter, when the oscillating member
26
is rotated in the one direction again, the bolt or the like is tightened. That is, in this ratchet wrench, only when the oscillating member
26
is rotated in one direction, is the shank
36
rotated, so that the bolt or the like is intermittently tightened.
In the ratchet wrench
Iritani Toshiro
Kamiya Tadashi
Danganan Joni B.
K-R Industry Company, Ltd.
Lorusso & Loud
Scherbel David A.
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