Note: Descriptions are shown in the official language in which they were submitted.
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DISCLOSURE
This invention relates to an adjustable box wrench for
gripping and turning hexagonal nuts and bolt heads.
The adjustable wrench currently available and in common use
is of the Crescent wrench type. It is an open-ended wrench in
which a movable jaw is adjusted by means of an adjustment screw
situated in the wrench head itself. Although it has the advan-
tage of being capable of engaging a nut from the side, where
this feature is essential, it also has several disadvantages:
Being open-ended, the jaws themselves must be thick enough
to withstand the force involved in using the wrench. This makes
the head bulky.
The adjustment nut and the guide for the movable jaw are
also situated in the head of the wrench. This adds to its bulk-
iness and makes the wrench difficult to use in confined spaces
with surrounding obstructions. The wrench cannot be used on a
nut that is recessed in any way.
Another problem with the Crescent type wrench is that it
grips only two of the faces of the hex nut or bolt head. In so
doing it applies torque force at only two of the six corners of
said hex nut or bolt head. If it is not used very carefully
this wrench can easily damage the corners of the nut.
An adjustable box wrench with a fixed jaw consisting of
two flat gripping surfaces with a 120 angle between them and a
movable jaw with two similar opposing surfaces has the advantage
of being able to grip four surfaces of the hex nut or bolt head.
In using the wrench torque force is applied at four corners out
of six.
Not only this, but an adjustable box wrench, like a box
' wrench of fixed size, having a fully enclosed opening, can have
strength without the bulkiness of the head of an open-ended
wrench.
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The bulkiness of the head can be further reduced by remov-
ing the adjustment nut from the head and locating it somewhere
in the handle or near the centre of the wrench. This position-
ing was accomplished by Karl Maichen of Austria in Can. Pat.
No. 765,206 in 1967, although the method of adjustment is not
an adjustment nut. This central adjustment can also be seen in
Can. Pat. No. 55,021 by Frederick Ellis in 1896 and in Can. Pat.
No. 55,837 in 1896. It can be seen that remote adjustment is
not a new idea.
The detachable socket wrench which is in such common use
demonstrates admirably the ability to reach down into a recess
or between obstructions. The problem is that one needs so many
individual sockets, which can become lost, and a carrying case
to hold them. One really needs two sets, one in metric and the
other in imperial measure.
Richard E. Cone in his Application for Canadian Patent
No. 2,007,531 dated 1991/01/11 shows a Reversible Adjustable
Wrench which also has the capacity to reach down into a recess
to engage a nut or bolt head. To do this both the fixed jaw and
2-0 the movable jaw extend downward. Since the use of such extended
jaws has a strong tendency to cause the movable jaw to rotate
around the longitudinal axis of the wrench, it is therefore nec-
essary to stabilize the movable jaw in relation to the fixed jaw.
In Richard Cone's invention the movable jaw and the elongated
slot in the wrench head have interlocking surfaces which co-
operate with each other in order to support the movable jaw. In
my opinion this solution is far too complicated and too bulky.
Richard Cone has also placed the adjustment nut in the head,
which adds to the bulkiness.
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The objective of my invention is to create an adjustable
box wrench of simple construction which will have the following
features which include the good features already mentioned above:
The head will be compact, consisting of only an open hexa-
gonal box and a movable jaw which moves within it.
The jaws will each have two surfaces separated by an ansle
of 120, allowing torque force to be exerted on four points of
the nut.
The jaws will be able to extend down into a recess.
When the wrench is reversed a second set of jaw extensions,
proportionately smaller, will handle more delicate work.
The movable jaw will be well-stabilized against twisting
(rotation around the longitudinal axis of the wrench).
The head will be separated from the handle by a shaft of
narrow dimensions, making the wrench handy in tight places.
The fixed jaw will allow the user to engage a nut very close
to an obstruction.
The adjustment nut will be located in such a position that
it can be manipulated by the thumb and forefinger while firmly
grasping the handle with the rest of the same hand. Only one
hand will be needed to operate the wrench.
The size of the jaw opening can be maintained simply by
keeping the thumb and forefinger on the adjustment nut while
using the wrench.
The adjustment nut will have a left-hand thread so that the
user tightens the grip to the right and loosens toward the left,
in conformity with our customary way of thinking.
The handle will contain a large slot so that the wrench may
be threaded onto a belt.
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The special structural features of the invention which
allow the attainment of the above operational features are as
follows:
The head of the wrench consists essentially of a slightly
elongated hexagonal box, open top and bottom, the two longest
sides of which are parallel to the longitudinal axis of the
wrench. The material in the box can be quite thin since the
strength of the box is derived from the width of the material,
i.e. the depth of the box. The parallel outer edges of the
upper main portion of the movable jaw, being the same width apart
as the side walls of the box, can slide forward and back between
them while being securely confined by them so that no rotation
of the movable jaw around the longitudinal axis of the wrench is
possible.
A tubular shaft connects the head to the handle. A rod
passes through the tubular shaft. To one end is welded or other-
wise permanently attached the movable jaw contained within the
head. The handle end of the rod is threaded so that it can be
engaged by the knurled adjustment nut. No rotation of the
movable jaw around the vertical or transverse axis is possible.
The wrench is of simple construction, has a compact head,
remote adjustment, and only three moving parts.
In the accompanying drawings, which illustrate a preferred
embodiment of the invention:
Figure 1 is a plan view of the wrench.
Figure 2 is a cross-section of a side view along the
line AA of Figure 1.
Figure 3 is an isometric view of the main part of the
wrench.
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Figure 4 is an isometric view of the threaded rod with the
movable jaw.
Figure 5 is an isometric view of the knurled adjustment
nut.
In this preferred embodiment of the invention 1, 2, 3, 4, 5
and 6 are the six sides of an open box which forms the "head" of
the wrench. All inside angles between the sides are 120.
Sides 2 and 3 comprise the fixed jaw of the wrench. At 7 a
round hole divided evenly between sides S and 6 of the head
allows the tubular shaft 11 to pass through, where it is welded
in place so that the end of the tube is flush with the inside
surfaces of sides 5 and 6. The handle consists of two side
pieces 8 and 9, the butt 29 and cross-brace 10. There is an
open space 12 between the sides 8 and 9. The handle is welded
to the tubular shaft 11 at points 13 and 14.
The movable jaw 18, the two flat sides of which contain an
angle of 120, is welded to the round rod 17. The rod 17 fits
in the tubular shaft 11 just loosely enough for it to be able to
- slide freely. This will allow no movement at all of the movable
jaw 18 around the vertical axis or the transverse axis. This is
a very important feature of the invention.
The two parallel sides 19 and 20 of the movable jaw fit in
close contact between the inside surfaces of the parallel sides 1
and 4 of the wrench head, but just loosely enough to allow the
movable jaw to slide forward and back freely. Since the movable
~ ~ jaw is confined by the parallel sides 1 and 4 for the total dis-
tance between the top edge 23 and the bottom edge 24 of the
wrench head, a distance which is more or less equal to the width
, of the head, rotation of the movable jaw around the longitudinal
axis of the wrench is effectively blocked. This is another very
important feature of this invention.
5.
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Since rotation of movable jaw 18 is so effectively blocked
around any axis it is possible and desirable to extend the fixed
jaw 2 and 3 downward to form extension 25 and to extend movable
jaw 18 downward to form extension 26. This allows the wrench to
reach downward to a nut or bolt head which is recessed or sur-
rounded by other obstructions. It also provides, if needed,
clearance for the fingers of the user. The extensions 25 and 26
are tapered somewhat as in 27 and 28 so that they can engage a
nut in a more restricted location (a tight spot). Similar exten-
sions 15 and 16 which are narrower and closer together allow thewrench to be used in the reversed position to engage hex nuts
of a smaller size. The extension of the jaws downward is an im-
portant feature of this invention.
The considerable de?th of the wrench head between the top
edge 23 and the bottom edge 24 allows the head to be made from
rather thin steel without sacrificing strength. This means,
among other things, that the fixed jaw is thin enough to engage
a nut which is very close to an obstruction. The general com-
pactness of the wrench head in a plan view is an important
feature of this invention.
The rod 17 is provided with a left-hand thread 21. Knurled
nut 22 is also left-hand threaded to engage threads 21 on the
rod. The knurled nut 22, which fits rotatably between the end of
the tubular shaft 11 and the cross-brace 10, will advance the
movable jaw 18 towards the fixed jaw 2 and 3 when turned towards
the right, thus tightening the grip on the bolt head or nut.
This is important for the handiness of the tool, since tradition-
ally an adjustment mechanism tightens to the right and slackens
to the left.
The position of the knurled adjustment nut 22 in the handle
j allows it to be manipulated with the thumb and forefinger while
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maintaining a firm grip on the handle. Furthermore, the desired
jaw opening can be maintained simply by leaving the thumb and
forefinger in place on the adjustment nut to prevent its turn-
ing. The completely one-handed operation of the wrench is an
important feature of this invention.
Although welding has been described for permanent attach-
ment of parts, this can of course be done by some other method.
It is to be noted that the wrench contains only three
moving parts and that it cannot be taken apart. Nor can it fall
apart. In this embodiment of the invention the final welds
attach side 1 to side 6 and side 4 to side 5.
