Tools – Wrench – screwdriver – or driver therefor – Slidable jaw adjustments
Reexamination Certificate
2001-03-26
2004-01-20
Meislin, D. S. (Department: 3723)
Tools
Wrench, screwdriver, or driver therefor
Slidable jaw adjustments
C081S133000, C081S157000, C081S173000
Reexamination Certificate
active
06679139
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to an adjustable sliding-jaw wrench and, more particularly to an adjustable sliding-jaw wrench providing a ratcheting mode of operation.
BACKGROUND OF THE INVENTION
An open-end wrench is a type of hand tool used to tighten or loosen a fastener, such as a nut or bolt. One type of open-end wrench is an adjustable sliding-jaw wrench, which uses a worm gear to drive a mating rack formed integrally with an adjustable sliding jaw. Rotating the worm gear adjusts the separation between the sliding jaw and a fixed jaw integrally formed with the handle of the wrench.
Adjustable sliding-jaw wrenches offer the particular advantage that the open-ended jaws can easily slip onto or off a fastener from the side. On the other hand, adjustable sliding-jaw wrenches cannot be used to rotate the fastener more than part of a single revolution unless the fastener is freely accessible. When rotation of the adjustable sliding-jaw wrench is hindered, the wrench must be removed and repositioned to further rotate the fastener.
Socket wrenches allow for a ratcheting mode of operation to torque a fastener without the need to remove and reposition the tool. Unfortunately, socket wrenches cannot slip onto or off of the fastener from the side and cannot be used when access to the top of the fastener is limited. Therefore, it is desirable to combine the features of an adjustable sliding-jaw wrench with a ratcheting mode of operation.
A number of solutions exist in the prior art for combining a ratcheting mode of operation with an adjustable sliding-jaw wrench. Many of the solutions require an extensive amount of manufacturing to accomplish. For example, some solutions use a camming operation or a pivoting handle to achieve the ratcheting effect. Although some of these wrenches may be effective, the difficulty and attendant cost of manufacturing makes them undesirable.
FIGS. 1A-C
illustrate an example of a ratcheting adjustable wrench
10
in the prior art as disclosed in U.S. Pat. No. 5,746,099 to Janson. Referring to
FIG. 1A
, ratcheting adjustable wrench
10
is cast or stamped out of steel and then machined. Wrench
10
includes a wrench head
12
having a handle
14
extending therefrom. A fixed jaw
16
also extends from wrench head
12
opposite handle
14
. A receiver
30
defines a longitudinal bore that extends through wrench head
12
and receives a movable member
40
therein. Movable member
40
includes a jaw
42
that opposes fixed jaw
16
and allows wrench
10
to clench a fastener F.
Movable member
40
also includes a toothed rack
44
that communicates with a large opening
50
. Large opening
50
extends through wrench head
12
and accommodates a worm gear
70
, a spindle
60
and a compression spring
62
therein. Spindle
60
is inserted into large opening
50
through a threaded aperture
64
. Worm gear
70
and spring
62
are positioned in large opening
50
. Worm gear
70
contains an axial bore (not shown), a widened portion of which receives one end of spring
62
. Spindle
60
passes through spring
62
and worm gear
70
until the end of spindle
60
lands in an aperture
66
opposite threaded aperture
64
. Spindle
60
then threads into threaded aperture
64
to support worm gear
70
and spring
62
within large opening
50
. In this way, worm gear
70
rides on spindle
60
, and spring
62
biases worm gear
70
to the top of large opening
50
.
Large opening
50
extends slightly into receiver
30
so that worm gear
70
engages with rack
44
on movable member
40
. A smaller opening
52
extends from large opening
50
on the side opposite from receiver
30
. Smaller opening
52
accepts a locking member
80
that is slideably mounted within smaller opening
52
. Locking member
80
, shown partially cut-away in
FIG. 1A
, slides within smaller opening
52
and covers a compression spring
88
in smaller opening
52
. Ideally, locking member
80
is assembled before the assembly of worm gear
70
, spindle
60
and spring
62
as described above. Those skilled in the art will appreciate that wrench
10
offers a number of challenges to manufacture and assemble.
In
FIG. 1A
, locking member
80
engages worm gear
70
in a locked position. The biasing of spring
88
urges locking member
80
towards spindle
60
in order to support worm gear
70
. In particular, a side protrusion
82
on locking member
80
is interposed between worm gear
70
and a sidewall
54
of large opening
50
. With locking member
80
in this locked position, worm gear
70
cannot slide along spindle
60
. Furthermore, movable member
40
, which is engaged with worm gear
70
, cannot move within receiver
30
unless worm gear
70
is rotated. With the support of locking member
80
, movable jaw
42
remains stationary relative to fixed jaw
16
so that wrench
10
may tighten or loosen the fastener F.
In
FIG. 1B
, locking member
80
is retracted from worm gear
70
to an unlocked position within small opening
52
. The retraction of locking member
80
overcomes the biasing of spring
88
. With locking member
80
in the unlocked position, worm gear
70
is no longer blocked by protrusion
82
and may slide along spindle
60
. Consequently, movable member
40
, engaged with worm gear
70
, may also slide within receiver
60
. With this freedom of movement, movable jaw
42
may slide away from fixed jaw
16
and accommodate the wider corner-to-corner dimension of the fastener F.
Although the design allows adjustable jaw
42
to move in relation to fixed jaw
12
when in the unlocked position, some problems exist in the operation of the tool. One particular disadvantage in the tool lies in the engagement of locking member
80
with worm gear
70
. As described in
FIG. 1A
, locking member
80
engages worm gear
70
when in the locked position.
FIG. 1C
illustrates a top view of the engagement of locking member
80
and worm gear
70
.
With reference to FIG.
1
A and more particularly to
FIG. 1C
, spindle
60
passes through a bore
72
of worm gear
70
. Spring
62
surrounds spindle
60
and lies partially within bore
72
of worm gear
70
. Locking member
80
is H-shaped with first and second protrusions
82
a
,
82
b
, a cross connector
84
, and a slideway
86
. Protrusions
82
a
,
82
b
interpose between worm gear
70
and sidewall
54
of large opening
50
to prevent worm gear
70
from sliding along spindle
60
. Cross connector
84
may also interpose between worm gear
70
and sidewall
54
. A portion of wrench head
12
is located within slideway
86
, and spring
88
biases locking member
80
towards spindle
60
and worm gear
70
.
Because worm gear
70
rides on spindle
60
, the protrusions
82
a
,
82
b
and cross connector
84
cannot support worm gear
70
on its axial center
72
. Protrusions
82
a
,
82
b
and cross connector
84
must fit around spindle
60
and spring
64
to accommodate them. Furthermore, the extension of the protrusions
82
a
,
82
b
under worm gear
70
is limited so that the protrusions
82
a
,
82
b
do not contact rack
44
of movable member
40
. Therefore, locking member
80
only partially supports worm gear
70
. The engagement of locking member
80
with worm gear
70
represents an inherently weak structure of the wrench
10
.
When the locked wrench
10
in
FIG. 1A
is used to tighten or loosen the fastener F, the corners of the fastener F bear on movable jaw
42
. Worm gear
70
is forced against locking member
80
. Because the engagement between locking member
80
with worm gear
70
is not axially aligned with the force applied, moment forces may be created on the structure of worm gear
70
, spindle
60
and locking member
80
. With the forces not axially aligned, wrench
10
may fail when torquing the fastener F.
Furthermore, the structure of wrench
10
requires careful machining of each component of the worm gear
70
, spindle
60
and locking member
80
to create the engagement of the locking mechanism. To avoid excessive “play” between the components, stringent tol
Emerson Electric Co.
Howrey Simon Arnold & White , LLP
Meislin D. S.
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