THIS INVENTION relates to a wrench.
The invention has particular application to an adjustable wrench of the type which has internally gripping jaws. However, it will be appreciated that the invention is not limited to this particular field of use, and may have application to other tools having movable jaws, such as bolt cutters, nut crackers, or other cutting and/or crushing tools.
Many types of wrench have been provided for gripping a mechanical element requiring application of torque for rotational movement or holding against rotation. Vise grips, for example, use a pair of jaws with multiple pivot points between the jaws together with a lever arm and over-centre locking arrangement for obtaining a tight grip on an element requiring turning. However, vise grips are sometimes difficult to remove from the article gripped and are limited in the size range of articles for which they are effective.
Multigrips have a wide range of size adjustments, but, for gripping an article, are limited to a simple mechanical advantage resulting from the ratio of the jaw length to the handle length, and a tight grip on the handles is required to maintain sufficient grip on the article.
The present invention aims to provide a wrench which alleviates one or more of the disadvantages of the prior art. Other aims and advantages may hereinafter become apparent.
With the foregoing in view, in one aspect, this invention resides broadly in a wrench including:
first and second jaw members each having first and second gripping portions for gripping an article to be rotated about a work axis and a leverage portion spaced from said gripping portion;
a handle connected to the leverage portion of the first jaw member for pivoting movement relative thereto about a leverage axis parallel to said work axis;
engagement means on said handle or operatively connected to said handle for movement therewith for engagement with the leverage portion of said second jaw member for urging said first and second leverage portions apart, and
connecting means connecting said first and second jaw members and holding them in opposed disposition, the connecting means being operatively interposed between said respective opposed gripping portions and said opposed leverage portions and being arranged to allow pivoting of one of said jaw members relative to the other, the connecting means being adjustable to vary the distance between the gripping portions to suit different sized articles.
In another aspect, the invention resides broadly in a wrench including:
first and second jaw members each having first and second gripping portions for gripping an article to be rotated about a work axis and a leverage portion spaced from said gripping portion;
handle connected to the leverage portion of the first jaw member for pivoting movement relative thereto about a leverage axis parallel to said work axis;
engagement means on said handle or operatively connected to said handle for movement therewith for engagement with the leverage portion of said second jaw member for urging said first and second leverage portions apart;
another handle in fixed relationship to and extending from the leverage portion of the second jaw member, and
connecting means connecting said first and second jaw members and holding them in opposed disposition, the connecting means being operatively interposed between said respective opposed gripping portions and said opposed leverage portions and being arranged to allow pivoting of one of said jaw members against the other, the connecting means being adjustable in length to vary the distance between the gripping portions to suit different sized articles.
Preferably the handles are located in the plane of rotation about the work axis. More preferably, the handles are arranged in operative juxtaposition with each other for gripping of both handles by the hand of a user, and such that the handle pivotally attached to the first jaw member may be pivoted towards the other handle to tighten the grip of the gripping portions and away from the other handle to loosen the grip of the gripping portions.
The connecting means is preferably length adjustable and in a preferred form is a length adjustable nut and bolt assembly. In one preferred form, the nut is in the form of a cylindrical pin having a diametral bore for receiving a length adjustable bolt comprising a sleeve and a screw in threaded engagement with a threaded bore extending axially into the sleeve. The nut is in pivotal co-operation with a complementary cylindrical housing provided in the jaw member for pivotal movement about an axis parallel to the work axis. It will be appreciated, however, that other shapes of nut may be provided which still provide pivotal engagement of the connecting means with the jaw member. Additionally, the wrench may be disassembled into its component parts, and in another aspect, the invention provides in the components for the wrench herein described.
Preferably, the nut and bolt assembly is pivotally connected to the first jaw member and the second jaw member includes an aperture for accommodating the length adjustable bolt, and permitting relative, but limited, pivoting movement of the length adjustable bolt within the aperture. More preferably, the aperture is in the form of a tapered bore tapering outwardly to its opening. The limiting of the pivoting may limit the amount of rolling of an article held between the respective jaw members. Preferably, the screw has a head held captive in a head retaining cavity provided in the second jaw member, and some of the perimeter of the head is exposed on one or both sides of the second jaw member for turning in a similar fashion to a thumb wheel. It is also preferred that the head retaining cavity is sized to hold the head captive with a limited degree of free movement axially with respect to the screw and also accommodate the limited degree of pivotal movement determined by the tapering bore in the second jaw member.
Preferably, biasing means is provided operatively connecting the jaw members for biasing the jaw members towards one another. More preferably, the biasing means comprises a coil spring with its respective ends engaging the respective jaw members intermediate the engagement means and the length adjustable bolt assembly means of each jaw member respectively. Preferably, the coil spring is operatively connected to the respective jaw members.
The engagement means is preferably a cam in fixed relationship with the handle and co-operable with an abutment surface on the leverage portion of the second jaw member for urging the leverage portions apart. The cam is preferably located close to the handle's pivotal connection to the first jaw member. The cam is preferably wedge shaped having a section which expands along a curved axis to provide an inner curved face and an outer curved face. Preferably, the inner curved face follows an arcuate course coaxial with the leverage axis, and the outer curved face follows a part spiral course from a pointed distal end outward from the inner face until the outer curved face meets the remainder of the handle. Thus, the cam is horn shaped in section when viewed along the leverage axis.
In order that the invention may be more readily understood and put into practical effect, reference will now be made to the accompanying drawings which illustrate two embodiments of the invention, and wherein:
FIG. 3. is a pictorial representation of another wrench according to the invention;
The wrench 10 illustrated in
The main pivot is on the other side of the retaining pin 32 from the gripping portion 15. The handle includes a cam 21 which is curved on an inner side to match the curvature of the main pivot and on an outer side is curved to form a curving wedge or horn shaped section, the outer curve of which is arranged to bear against a bearing surface 20 on the second body portion 17 of the second jaw member. The spring 19 is retained in the first and an second jaw members inside a spring retaining aperture 22 in the first and second body portions, and is arranged to have a biasing force urging the body portions of the jaw members towards one another, whereas the cam and bearing surface act together to move the body portions of the jaw members apart, the relative movement between the respective body portions being pivotal by virtue of the retaining pin in the first body portion. Accordingly, part of the body portions remote from the gripping portions may be considered as leverage portions described above.
The wrench 30 illustrated in
Referring to
Referring to
The first jaw member also has a convex mating surface 35 which is an arcuate part of a circle on the lower side of the first jaw member. The convex mating surface matches in radius a concave mating surface 45 on the upper side of the second body portion of the second jaw member 12. The second jaw member 12 also includes the bearing surface 20 which, as can be seen from
The length adjustable bolt assembly 14 is shown assembled in FIG. 7 and its three main parts are shown in
The handle 13 illustrated in
Referring to
Referring to
By turning the adjusting bolt so that it is screwed outward from the threaded sleeve, the first and second jaw members can be widened to grip a large diameter article 88 having a large diameter represented by dimension arrows 89. Moving the handle in the direction of the arrow 84 not only causes a tightening of the grip of the jaws on the articles, but also imparts a torque in the direction of the arrow 82 in a similar fashion to that described in respect of
In each instance, the cam 21 may be inserted between the body portions of each jaw members by pivoting of the handle with respect to the first jaw member, the separating force caused by the outer face of the cam bearing on the bearing surface being accommodated by the head of the adjusting bolt bearing down upon the base of the counterbore, placing the adjusting bolt in tension with respect to the threaded sleeve, the tension in the threaded sleeve being taken up by the retaining pin 32. It will be seen that the wrench of the present invention uses a double lever principle, one lever being the jaw members acting in concert with the connecting means, the load for the lever being the gripping force applied to the article being gripped by the jaw members, the fulcrum being the connecting means restraining the jaw members from moving further apart than the adjusted length of the setting of the adjusting bolt, and the activation of the lever being performed by the action of the cam on the bearing surface. The second lever is the handle in its pivoting relationship with the first jaw member and the wedging action of the cam on the second jaw member, the load being the separating action of the cam on the bearing surface, the fulcrum being the pivoting connection between the handle and the first jaw member, and the activation of the lever being performed by the pivoting of the handle as hereinbefore described.
In the case of the two handle wrench, the length adjustable bolt assembly may be adjusted so that moving the handles together until the mating surfaces of the limiting lands meet. If the article to be gripped is larger than the adjusted separation of the jaw members when the mating surfaces meet, imparting a force on the first handle as described in relation to the one handle wrench will impart a torque on the article being gripped. However, if desired, a reverse torque may be applied to the article being gripped, the tightening of the jaws onto the article being achieved by closing the handles together.
Although the invention has been described with reference to particular examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms within the broad scope and ambit of the invention as defined by the following claims.
Number | Date | Country | Kind |
---|---|---|---|
PQ 3166 | Sep 1999 | AU | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
---|---|---|---|---|
PCTAU00/01173 | 9/27/2000 | WO | 00 | 3/28/2002 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO0123146 | 4/5/2001 | WO | A |
Number | Name | Date | Kind |
---|---|---|---|
167085 | Evarts | Aug 1875 | A |
1053891 | Steinke | Feb 1913 | A |
1493741 | Ellison | May 1924 | A |
2537838 | Logan | Jan 1951 | A |
6223630 | Stanton | May 2001 | B1 |
6412372 | Hsu | Jul 2002 | B1 |
Number | Date | Country |
---|---|---|
767401 | Feb 1957 | DE |
1403411 | Oct 1963 | DE |
628301 | Aug 1949 | SE |