CA2074379C

CA2074379C - Adjustable box wrench

Info

Publication number: CA2074379C
Application number: CA 2074379
Authority: CA
Inventors: Frank Peter Holm
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-07-21
Filing date: 1992-07-21
Publication date: 1995-01-17
Anticipated expiration: 2012-07-21
Also published as: CA2074379A1

Abstract

In an adjustable box wrench for gripping hexagonal nuts and bolt heads, the wrench consists of three movable parts.
The first part consists of a hexagonally shaped head, open top and bottom, permanently attached to a hollow tubular shaft which is attached to a handle. The extremity of the head has two gripping surfaces at 120° to one another, forming the fixed jaw of the wrench. The second part is a movable jaw with simi-lar oppositely placed gripping surfaces permanently attached to a rod which passes through the tubular shaft and is threaded on the end where it leaves the tubular shaft and enters the handle.
The third movable part is a knurled adjustment nut which is restricted in its forward and backward movement but which engages the threaded end of the rod and thus can advance and retract the movable jaw. The invention places the adjustment screw in the handle instead of in the head of the wrench, thus reducing the bulkiness in the head while also allowing the user to operate the wrench with one hand. The adjustment nut can be manipulated by the thumb and forefinger while firmly gripping the handle with the rest of the hand. Since the parallel lateral surfaces of the movable jaw are slidably confined by the two parallel inner surfaces of the sides of the head, the jaws of the wrench can be extended downward to engage a hexagonal nut or bolt head which is recessed.

Description

207~379 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.
1 .

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.
) 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.

2~74379 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.

-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.

-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 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.

Claims

1. An improved adjustable box wrench for gripping hexagonal nuts and bolt heads, the wrench having a longitudinal axis and consisting of three parts:
a first, or main part, elongated along and in parallel to the longitudinal axis, the first part having a head, a handle and a hollow tubular connecting shaft located between the head and the handle and integrally attached to both: the head and the handle, the head having a form of an elongated hexagonal box with two elongated sides located opposite each other and in parallel to the longitudinal axis, the head including a fixed jaw at a distal end thereof, the jaw having two gripping surfaces at 120°
to one another, the connecting tubular shaft opens at one end into the head and at another end into a recess formed in the handle;
a second part comprises a round, threaded rod remaining in sliding and non-rotatable relationship within the connecting shaft and integrally connected to a sliding jaw, the jaw having two gripping surfaces at 120° to one another and being able to slide toward and away from the fixed jaw along the two elongated sides of the box, the threaded rod at a distal end thereof ex-tends into the recess in the handle;
a third part comprises an adjustment means fitting rotatably into the recess in the handle over the distal end of the threaded rod;
where the improvement consists of a reduced bulkiness of the head while allowing a user for operation of the adjustment means with one finger without loosing a firm gripping over the handle and for engaging the jaws in area remote from a hand of the user.

8.

2. The adjustable wrench as defined in claim 1 in which the adjustment means is a knurled nut.

3. The adjustable wrench as defined in claim 2 in which the knurled nut and the threaded rod are provided with a left-hand thread.

4. The adjustable wrench as defined in any one of claims 1 to 3, where the fixed jaw and the movable jaw, both are extending through the elongated hexagonal box and away from the box.

9.