Note: Descriptions are shown in the official language in which they were submitted.
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This invention relates to an adjustable gripping tool
and more particularly to an adjustable gripping tool capable
of exerting pressure on a plurality of torque pressure points on
a work object having sides.
Adjustable gripping tools or wrenches having a fixed jaw
and an adjustable jaw are well known. Generally, each jaw is
provided with aflat contacting surface, the surfaces of both jaws
co-acting to engage opposite parallel sides of a work object
such as a fastener comprising a hexagonal nut or bolt head. Only
two torque pressure points may be obtained using this form of
wrench which presents a problem when an attempt is made to
release a fastener that may be frozen by rust. A common tendency
in such wrenches is for the jaws to slightly spring apart as
torque is increased. As a result, in situations where excessive
torque pressure is required, the spring-open tendency of the jaws
tends to round the corners of the fastener.
To overcome the problems of the foregoing prior art
adjustable wrenches, adjustable wrench designs have appeared in
which as many as four or five fastener contacting surfaces have
been provided. In general, the flat gripping surfaces of a simple
prior art adjustable wrench are formed into two V-shaped surfaces
which define and include an angle of 120. This angle corres-
ponds to the angle between adjacent surfaces of a hexagonal
fastener and is an industry standard.
Characterizing examples of the prior art may be seen
in U.S. patent 54,040, Symonds, an old patent issued in 1866,
and 3,015,246, Buyer, which by comparison is relatively recent,
having issued in 1962. While the prior art on adjustable wrenches
is relatively extensive, the Symonds and Buyer patents typify
the limits in time during which patents on adjustable wrenches
have issued as well as the extent of inventive ideas resorted to
in an effort to overcome the deficiencies of the simple two
torque point wrench.
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According to the Symonds patent an adjustable wrench is
disclosed having the capability of exerting pressure on as many
as five torque pressure points on a hexagonal fastener. It is
noted, however, that Symonds has not entirely escaped the problems
of the aforementioned simple adjustable wrenches for the reason
that the two contacting surfaces of the fixed jaw in Symonds
wrench are relatively short in length and may, under high torque
pressures, spring outwardly to round the corner of a fastener
in like manner to the simple adjustable wrench having two torque
points. Presumably, the Symonds wrench was designed in this manner
to accommodate a wide range of fastener sizes. It is apparent
that where all jaw surfaces are equal in length, the jaws may
not approach as closely together. By making the contacting ~;
surfaces of the upper jaw shorter than corresponding surfaces in
the lower jaw, both jaws may be drawn more closely together to
accommodate fasteners of small size.
In the Buyer patent it is recogni~ed that the jaws of an
adjustable wrench must engage corresponding surfaces of a fastener -
so as to completely span two adjacent sides in order to provide
a resultant grip that is firm and which distributes the turning
-forces over a larger area of the fastener. To this end, the
wrench disclosed by Buyer is provided with a hook jaw having a `
V-shaped fastener engaging surface and a heel jaw having only
one surface which operates as a fulcrum. Thus, Buyer discloses
an adjustable wrench having only three contacting surfaces for
fasteners of all sizes. A fourth contacting surface in the heel
jaw is eliminated in order to gain the advantage of easy access
to a fastener without having to excessively open the jaws of the ;~
wrench. In one embodiment disclosed by Buyer, a fourth jaw surface
becomes available when the wrench is opened to its maximum. For
general applications, howeYer, the Buyer wrench engages only
three surfaces of a fastener and thus exerts pressure at only
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three torque pressure points. It would appear that Buyer was
drawn to this structure in order to have two faces of equal length
in the hook jaw so as to completely span two adjacent sides of
the fastener. By removing the one surface of the heel jaw,easy
access to the fastener is obtained and both jaws may be brought
more closely together to accommodate a wide range of fastener
sizes. This advantage, however, was gained at the expense of
losing one torque pressure point.
An object of the present invention is to provide an
adjustable wrench which will exert pressure on at least four
torque pressure points on a work object such as a fastener.
Another object of this invention is to provide an adjustable
wrench which does not require fully opening the jaws each time
a new grip is taken on a fastener after the fastener has been
started by a portion of the wrench capable of exerting pressure
on at least four torque pressure points.
A still further object of the invention is to provide
an adjustable wrench having at least two fastener contacting
surfaces which are sufficiently large to completely span and
engage two opposite sides of a fastener in order to distribute
the turning forces over a larger area.
It is a still further object of the invention to provide
an adjustable wrench in which the opposing jaws may he closely
brought together in order to accommodate a wide range of fastener
sizes.
The foregoing disadvantages of the prior art may be
substantially overcome and the preceding objectives achieved by
recourse to the present invention which is an adjustable wrench for
exerting pressure at a plurality of torque pressure points on a
work object having sides. The wrench comprises a longitudinally
extended body having a fixed jaw at one end, a handle at the other
end and an adjustable jaw which is slidably disposed along a portion
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of the body for gripping the object between the jaws. Each
jaw has an inner and an outer face adapted to contact a pair
of adjacent sides of the object. The faces are unequal in
length with the longer face adapted to completely span and
engage one side of the object; the shorter face adapted to
contact at least a portion of the adjacent side of the object
and the jaw faces corresponding in length being disposed in
opposing parallel relation. An adjustment means cooperating
with the body and the adjustable jaw is provided for locating
the adjustable jaw on the body in a predetermined fixedposition.
The invention will now be more particularly described
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with reference to embodiments thereof shown, by way of example,
in the accompanying drawings wherein:
Fig. 1 is a perspective view of an adjustable wrench
in accordance with the invention and is shown gripping a large
hexagonal fastener;
Fig. 2 is a plan view of another embodiment of the
invention;
Fig. 3 is a plan view of still another embodiment
of the invention; and
Fig. 4 is a side view of the wrench of Fig. 1.
In Fig. 1, there is shown an adjustable wrench 10
that is particularly adapted to exert a pressure on at least
four torque pressure points on a work object having sides. The
work object is shown as a hexagonal nut 11. It should be noted
that the nut 11 may comprise a conventional nut or abQltheador
some other object such as a hexagonal bar orother suchpolygonal
object. The wrench 10 includes a longitudinally extendedbody 12
having a fixed jaw 13at oneend and a handle portion 14 at the
30 other end. An adjustable jaw 15 is slidably disposed along the ~
body 12 for gripping the fastener llbetween the jaws13and 15. ~-
Each jaw is provided with a longer face 16 and a shorter face 17.
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Thelonger and shor~ faces are adapted to contact a pair of
corresponding adjacent sides on the nut 11. As may be seen in
Fig. 1, two pairs of oppositely disposed parallel sides of the nut
11 are gripped by corresponding pairs of longer and shorter faces
16 and 17, respectively. The faces 16 and 17 of the jaws are
unequal in length with each longer face being adapted to completely
span and engage one side of the nut 11. Although ~ch shorter
face is adapted to contact only a portion of the side adjacent
to the side of the nut 11 which is engaged by the longer face,
the portion that it does contact is adequate for exerting a
torque pressure. However, the longer faces are more effective
for exerting torque pressures since they completely span opposite
sides of the fastener and thus distribute the tor~ue load over
a greater area.
It has been determined that a good practical ratio of
jaw face lengths exists which permits bringing together the jaws
13 and 15 in sufficiently close relation to handle a wide range
of fastener sizes. The ratio of the effective lengths of the
jaw faces 16 and 17 in Figs. 1 and 3 is 2:1.
Whereas each jaw 13 and 15 has been described as including
an inner and an outer face comprising a long face and a short
face, the fixed jaw 13 also includes an additional jaw face 20.
The jaw faces 16 and 17 form an included angle of 120 and are
work-engaging surfaces. The face 20 in the fixed jaw 13 is not
normally used as a work-engaging surface in the embodiments of
Figs. 1 and 3. However, a further embodiment of this invention
does use the face 20 as a work-engaging surface as will be later
described. In the embodiments of Figs. 1 to 3, the face 20 angles
away from the face 17 of the jaw 13 in order to contact the work-
engaging outersurface, shown as the longer face 16, of the adjustable
jaw 15. In this way, the jaws may be brought together sufficiently
close so as to enable handling a wide range of fastener sizes.
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It will be apparent from the foregoing description that
in the embodiments of Figs. 1 to 3, the angle between the faces
16 and 17 of each jaw corresponds to the angle between adjacent
corresponding surfaces of the nut 11. The overall result of the
embodiments is to provide an adjustable wrench which will develop
pressures on at least four torque pressure points on the nut 11.
When the jaws are at a maximum opening, as illustrated in Fig. 1,
a fifth torque pressure point becomes available. This arises
from a fifth jaw face 21 which forms a surface portion of the
fixed jaw 13 that is adjacent to the longer face 16 thereof. As
shown, the fifth face 21 engages a corresponding fifth side of
the nut 11 when the jaws are spaced apart a predetermined distance.
Two faces of the four faces on the jaws 13 and 15 fully
contact corresponding faces of the nut 11. This feature allows
a good grip on the flat portions thereof. The end portions 20
and 20' of the wrench jaws 13 and 15 are cut away at an angle
which corresponds to the two long faces 16 which completely span
corresponding surfaces of the nut 11. In this way, the wrench
jaws are permitted to closely approach one another so as to
accommodate fasteners of small size.
The two long faces 16 which fully span and contact two
faces of the nut 11 are disposed in opposed parallel relation.
This allows the application of maximum torque while reducing
the tendency to damage the nut 11 by rounding the corners. If
the two long faces 16 are placed in adjacent relation, as taught
in the prior art, the two short faces 17, which would then be
in opposing relation, contact a relatively small area of the
nut 11 so that the corners of the fastener are more easily `
damaged. This situation may readily occur in high torque
application-s where the wrench jaws tend to spring open a little.
- A wrench jaw having a small gripping area would therefore tend to
slip and round off a gripped corner. ~owever, since the two long
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faces 16 are in opposing relation, there is a substantially
reduced tendency for an adjacent pair of faces 16 and 17 in either
jaw 13 or 15 to slide over a corner of the nut 11.
Adjustment means are provided for locating the adjustable
jaw 15 on the body 12 in a predetermined fixed position so as to
adequately grip the work surfaces of the nut 11. This is clearly
shown in the figures. The adjustment means is well known in
the art of adjustable wrenches and includes a knurled worm gear
22 which engages a corresponding linear gear 23 that forms a
portion of the jaw 15. The gear 23 and the jaw 15 are joined by
a web 26 portion of the jaw. In accordance with common knowledge
in the art, the gear 23 and web 26 slidably engage a guideway 24 in
the body 12 so that the position of the jaw 15 relative to the jaw
13 will be held fixed at any setting of the gear 22. These
structural features are readily apparent in the side view of Fig. 4
which also shows a screw 25 that holds the gear 22 in rotatable
relation with the gear 23.
Fig. 2 is similar to Fig. 1, with the jaws 13 and 15 shown
in an open position to accommodate a large nut 11. The embodiment
of Fig. 2 shows a somewhat longer face 16 in the adjustable jaw
15 as well as a somewhat longer end portion 20 in the fixed jaw 13.
The purpose of these modifications is to permit gripping a fastener
by the surfaces 16 and 20 in order to reach into tight corners
or restricted areas to turn the nut 11 after the nut has been
started by means of full engagement with the surfaces 16 and 17
of the fixed and adjustable jaws 13 and 15~ respectively.
Whereas the embodiment of the invention illustrated in
Fig. 1 indicates that the fifth jaw face 21 is located on a portion
of the fixed jaw 13, it would be apparent to a workman skilled
in the art to modify the wrench shown so that the jaw face 21
is disposed on the adjustable jaw 15.
Fig. 3 illustrates a further embodiment of the invention
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wherein the fifth jaw face 21 is formed by the web 26 of the
movable jaw 15 instead of a portion of the fixed jaw 13. Aside
from this particular characterizing feature, the wrench functions
in substantially the same manner as the embodiments illustrated
in the other flgures.
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