FIELD OF THE INVENTION

The present invention generally relates to locking-type wrenches. More specifically, the present invention relates to locking-type wrenches which are especially adapted such that the operating handles may be positionally restrained.

BACKGROUND AND SUMMARY OF THE INVENTION

Locking wrenches are well known tools that are employed in situations where it is desirable to clamp one structural member to another so that the operator's hands may be freed to accomplish other tasks. Examples of conventional locking wrenches include those wrenches disclosed in prior-issued U.S. Pat. No. 2,280,005 issued to William Peterson on Apr. 14, 1942; U.S. Pat. No. 2,514,130 issued to Harold T. Jones on July 4, 1950; and U.S. Pat. No. 2,592,807 issued to Harold T. Jones on Apr. 15, 1952 (the entire content of each of these prior-issued U.S. Patents being expressly incorporated hereinto by reference).

Conventional locking wrenches are generally comprised of an upper handle having a fixed-position upper jaw at its forward end and a threaded sleeve at its rearward end. A pivotally movable lower jaw is disposed in opposition to the upper jaw and is moved towards and away from the upper jaw by means of a lower operating handle (which is itself pivotally connected to the lower jaw). A toggle lever is pivotally connected at one end to the lower operating handle, and is slidably received within the upper handle at its opposite end. Typically, a tension spring biases the lower jaw in a pivotal direction tending to separate it from the upper jaw. An adjustment screw is threadably coupled within the sleeve of the upper handle and has a terminal end that acts upon the opposite end of the toggle lever.

As those in the art will appreciate, due to the relative connections between the toggle lever, lower operating handle, and lower jaw, turning movements applied to the adjustment screw will responsively cause the lower jaw to be moved pivotally relative to the fixed upper jaw. In this manner, the clamping force that is exerted by the upper and lower jaws may be selectively adjusted by the operator. In addition, the toggle lever increases the clamping force that is applied to structural members held between the upper and lower jaws when the lower operating handle is forcibly moved into a closed condition relative to the upper handle.

While conventional clamping wrenches function to clamp structural members securely one to another, there is a risk that the clamping force may suddenly be released--e.g., as might occur should the wrench and/or structural members held by the wrench be struck by an object with sufficient force to cause the lower operating handle to be moved under the influence of the tension spring to an opened condition relative to the upper handle. Sudden release of the clamping force may, in turn, release the structural members that had just moments before been securely clamped and allow them to strike the operator and/or others in the vicinity of the work area thereby causing potentially serious injuries.

One prior proposal for positionally restraining the upper and lower handles of a locking wrench is represented by U.S. Pat. No. 4,889,021 issued to Joseph L. to Morrison on Dec. 26, 1989. According to Morrison '021, the upper and lower handles of a locking wrench are provided with vertically aligned apertures so as to accommodate upper and lower stubs associated with an especially adapted padlock. The upper stub moreover bears against a brake means located physically within the upper handle member so as to apply braking force against the adjustment screw thereby inhibiting its turning movements.

While the locking wrench proposal in Morrison '021 appears to function in a manner that would minimize the risk of sudden release of the clamping force, it necessarily requires a separate and especially adapted padlock to always be available to the operator.

What has been needed therefore are improvements to conventional locking-type wrenches which would significantly reduce (if not eliminate entirely) the risks associated with the inadvertent sudden release of a wrench's clamping force and which would not require especially adapted restraining elements. Thus, locking-type wrenches that are inherently safer and more convenient to use have been needed. It is towards fulfilling such needs that the present invention is directed.

According to the present invention novel locking-type wrenches are provided such that the upper and lower handles are positionally restrained or immobilized relative to one another. More specifically, preferred embodiments of the present invention include a rearwardly directed extension member that defines an aperture associated with the lower operating handle, and means associated with the adjustment screw to coact with the aperture in the lower handle flange extension so as to positionally restrain the upper and lower handles relative to one another.

According to some preferred embodiments of the present invention, the head of the adjustment screw includes pairs of radially extending wings each of which defines an opening. The extension member is rigid with the lower operating handle and is located at a position such that it may be brought into an adjacent position with one of the wings when the lower operating handle is in a closed condition relative to the upper handle. Thus, when the extension member is adjacently positioned relative to one of the wings (i.e., when the lower operating handle is in a closed condition), the respective opening defined in that one wing and the aperture defined in the extension member will be in alignment. In such a manner, a restraining element (which could be virtually any suitable rigid or flexible member, such as a bolt, pin, rod, tube, padlock hasp, wire, rope, or the like) may be passed through the aligned opening/aperture to thereby positionally restrain the upper and lower handle members relative to one another. The risk of inadvertent sudden release of the clamping force is thereby minimized (if not eliminated).

Other embodiments of the invention include apertured adjustment screw heads of selected geometrical configuration, and an opening defined in the extension member. The extension member according to these alternative embodiments will likewise be oriented so that it is adjacent to the apertured adjustment screw head when the lower operating handle member is in its closed condition so that at least one of its defined apertures will be in alignment with an opening formed in the extension member.

The extension member may include a movable restraining element that defines an opening. The restraining element may be pivoted, for example, so that its defined opening is brought into operative association with a key flange associated with the adjustment screw head so as to positionally restrain the upper and lower operating handles when in their closed condition.

Further aspects and advantages of this invention will become more clear after careful consideration is give to the following detailed description of the preferred exemplary embodiments thereof.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

Reference will hereinafter be made to the accompanying drawings wherein like reference numerals throughout the various FIGURES denote like structural elements, and wherein;

FIG. 1 is a perspective view of the novel locking pliers according to this invention and shown being exemplary used to clamp bar stock to a work surface;

FIG. 2 is a side elevational view of the locking wrench according to the present invention and depicted with the operating handles in a closed condition;

FIG. 3 is a side elevational view of the locking wrench according to the present invention similar to FIG. 2, but shown with the operating handles in an open condition;

FIG. 4 is an end elevational view of the locking wrench of this invention as taken along line 4--4 in FIG. 2;

FIG. 5 is a partial side elevational view of an alternative embodiment of a locking wrench according to the present invention;

FIG. 6 is a cross-sectional elevational view of the wrench shown in FIG. 5 as taken along line 6--6 therein;

FIG. 7 is an end elevational view of another embodiment of a locking wrench according to the present invention;

FIG. 8 is a partial side elevational view of an alternative embodiment of a locking wrench according to the present invention; and

FIG. 9 is a cross-sectional elevational view of the wrench shown in FIG. 8 as taken along line 9--9 therein.

DETAILED DESCRIPTION OF THE DRAWINGS

Accompanying FIG. 1 shows a locking wrench 10 according to the present invention in an exemplary use environment to clamp a piece of bar stock 12 to a work surface 14. The wrench 10 is generally comprised of a forward locking wrench subassembly 16 (which in and of itself is conventional) and a rearward handle-restraining subassembly 18 (which incorporates the modifications according to the present invention).

As is perhaps more clearly shown in FIGS. 2-4, the locking wrench subassembly 16 includes an upper handle 20 having an upper jaw 22 rigidly fixed to the upper handle 20 at the latter's forward end. A lower jaw 24 is opposed to the upper jaw 22 and is pivotally connected to the upper handle 20 via pivot pin 26. A distal end of the lower operating handle 28 is connected pivotally to the lower jaw 24 at pin 30. Movements of the lower operating handle 28 between its closed condition (i.e., as shown in FIG. 2) and its opened condition (i.e., as shown in FIG. 3) will thereby responsively cause the lower jaw 24 to pivot between respective positions that are closer to and farther from the upper jaw 22.

A tension spring 32 operating between the upper handle 20 and the lower jaw 24 encourages the latter to pivot about pin 26 in a direction which separates the upper and lower jaws 22, 24, respectively (i.e., in a counterclockwise direction as viewed in FIGS. 2 and 3). Optionally, a release lever 33 may be provided so as to facilitate release of the clamping force between jaws 22 and 24--that is, to facilitate movement of the operating handle 28 from its closed condition to its opened condition.

A toggle lever 34 extends between the upper handle 20 and the lower operating handle 28. The toggle lever 34 is pivotally connected at one of its ends to the lower operating handle 28 at a pivot pin 36 rearwardly of the pivot pin 30 and is axially slidably received within the upper handle 20 by suitable means (not shown) at the other of its ends.

The threaded shank 40 of adjustment screw 42 is coupled operatively to the threaded sleeve 44 (see FIGS. 1 and 4) which axial extends within the rearward end of the upper handle 20. As is well known in this art, the terminal end of the threaded shank 18 will coact with the toggle lever 34 so as to in turn allow the operator to select the clamping force exerted between the upper and lower jaws 22, 24, respectively (i.e., in dependance upon the direction of turning movements applied to the adjustment screw 42).

The improvements according to the present invention are essentially embodied in the handle-restraining subassembly 18. In this regard, the adjustment screw 42 is preferably provided with opposing pairs of radially extending wings 46, each of which preferably defines an opening 48.

The proximal end of the operating handle 28 is provided with a flange extension 50 which defines an aperture 52 therethrough. As can be seen particularly in FIG. 2, the flange 50 moves into adjacent relationship to one of the radially extending wings 46 when the lower handle member 28 is forcibly moved into its closed condition. The aperture 52 defined in the flange extension 50 and the opening 48 defined in that one wing 46 which is adjacent to the flange extension will thereby be aligned to allow a restraining element, for example the hasp H of a conventional padlock P, to pass therethrough and thereby positionally retain the lower handle member in its closed condition. In this manner, the clamping force exerted by the upper and lower jaws 22, 24, respectively, will be maintained. Use of the padlock P as the restraining element will also increase security to minimize theft of objects upon which the wrench 10 is clamped.

The lower operating handle 28 usually will have some "play" (as depicted by the chain line representation thereof in FIG. 2) present due to the manner in which the toggle lever 34 and tension spring 32 functionally cooperate. That is, since the tension spring 32 and toggle lever 34 in essence collectively serve as an "over-the-center" assembly, the operating handle 28 will typically be allowed some minor range of opening movement before the clamping force of the jaws 22, 24 is released (i.e., before the force alignment imparted by the tension spring 32 is "over-the-center" of the toggle lever 34). The aperture 52 of the extension flange is thus preferably upwardly elongated (i.e., relative to the upper handle 20) so as to accommodate the "play" that is typically present with the lower operating handle 28.

The restraining element is not necessarily required to effect an absolute rigid union between the upper and lower handles 20, 28, respectively. In other words, since the lower operating handle 28 will usually exhibit some "play" before the clamping force between the jaws 22, 24 is released, it is only important according to the present invention that relative movements between the upper and lower handles 20, 28, respectively, be restrained to the extent of such "play". Because of this, flexible restraining elements such as wire, rope, cable rovings, chain or the like may be used to positionally restrain the upper and lower handle members 20, 28, respectively relative to one another. In other words, according to the present invention, positional handle restraint may be achieved by passing a length of a flexible restraining element through an aligned opening 48 and aperture 52 and then tying or twisting the ends of the flexible element to one another.

As will be understood from the discussion above, therefore, rigid restraining elements other than the padlock hasp H shown in the accompanying drawings could likewise be employed. Thus, for example, rigid bolts, pins, rods, tubing, and the like may be used as the restraining elements according to the present invention.

Although two opposing pairs of wings 46 are shown in the accompanying drawings, greater/lesser numbers of wings may be provided as may be deemed necessary. Thus, if greater "fine" adjustment of the clamping force is desired, then a greater number of wings may be provided, and vice versa. In addition, the flange extension need not be upwardly oriented as shown but could be angled (e.g., L-shaped) or provided in any other desired configuration as long as its aperture and an opening defined in one of the wings 46 are capable of being aligned when the lower operating handle 28 in a closed condition.

In addition to providing the means whereby the upper and lower handles 20, 28, respectively, may be positionally restrained when operatively coupled to the extension flange as described previously, the opposing pairs of radially extending wings 46 define levers of sorts which more easily facilitate manual turning movements applied to the adjustment screw 42.

In this regard, conventional locking-type wrenches usually include a knurled knob at the head of the adjustment screw which is extremely difficult (if not impossible) to operate when the jaws are in a clamped condition. However, because of the lever action provided by the radially extending wings 46, the adjustment screw 42 may be relatively easily turned manually by the operator even when the upper and lower jaws 22, 24 are in a clamped condition (i.e., when the lower operating handle 28 is in a closed condition). Thus, novel locking wrenches according to the present invention may simply be provided with at least one opposing pair of wings 46 in the event the handle restraining functions described previously are not deemed necessary.

The adjustment screw 42 with radially extending wings 46 may also be provided to the market as a "retrofit" item as a replacement for the knurled knob adjustment screw conventionally associated with locking wrenches. Hence, the functional attributes mentioned above can be realized by replacing the conventional knurled knob adjustment screw of those locking wrenches currently in the market with the novel "winged" adjustment screw 42 according to the present invention.

An alternative embodiment of the present invention is shown in accompanying FIGS. 5 and 6. As is seen therein, the extension flange 60 is upwardly and forwardly bent (e.g., generally C-shaped) so as to terminate in an essentially horizontally disposed tail flange 60a which defines an aperture 60b and is spaced above the lower operating handle 28 by means of upright flange portion 60c. The adjustment screw 62 includes a threaded shank portion 62a which is threadably coupled to the upper handle 20, and a knurled cylindrical head portion 62b. The knurled head portion 62b preferably defines a pair of mutually intersecting axially elongate openings 62c, 62d. A single one of the openings 62c, 62d or more than a pair of openings 62c, 62d may be provided, if desired.

As is perhaps more clearly shown in FIG. 6, the uppermost surface 60d of the tail flange 60a is concave so as to generally conform to the arcuate external surface of the adjustment screw's head portion 62b. In this manner, the tail flange 60a and the aperture 60b defined thereby may be brought into closely adjacent relationship with the external cylindrical surface of the head portion 62b of adjustment screw 62 when the lower operating handle 28 is in its closed state. Thus, one of the openings 62c, 62d defined by the head portion 62b will be capable of being brought into registry with the aperture 60b so that a restraining element may be passed therethrough in a manner similar to that described previously.

Accompanying FIG. 7 shows one possible modification to the embodiment described above in FIGS. 5-6. In this connection, it will be noted that the head portion 62b' of the adjustment screw 62' similarly defines a pair of mutually intersecting apertures 62c' and 62d' which open onto the valleys between adjacent respective ones of raised longitudinally extending lobes 62e'. The lobes 62e' serve to facilitate manipulation of the adjustment screw 62' by the user.

The tail flange 60a' of the extension flange 60' defines an aperture 60b' therethrough which is adapted to being brought into adjacent registry with one of the openings 62c', 62d' in a manner similar to that described above in connection with the embodiment shown in FIGS. 5 and 6. It will be observed, however, that the uppermost surface 60d' of the tail flange 60b' is convexly curved so as to closely match the concave curvature in the valley regions between adjacent lobes 62e'. Thus, the tail flange 60b' is able to be brought into closely adjacent relationship to the exterior surface in the valley regions between adjacent lobes 62e' when the upper and lower handles 20, 28 are in a closed condition so that the aperture 60b' and one of the openings 62c', 62d' may be aligned with one another. It will be appreciated that the cooperation between the convex surface 60c' of the tail flange 60a' and the valley regions between adjacent lobes 62e' will furthermore serve to impede turning movements being applied to the adjustment screw 62' when the handles 20, 28 are in a closed condition.

Accompanying FIGS. 8 and 9 show a further embodiment of a wrench according to the present invention as including an extension flange 70 rearwardly extending from the lower handle 28 and defining a longitudinally oriented slot 72. The adjustment screw 74 includes a threaded shank portion 74a which, like the other embodiments described above, is adapted to being threadably coupled axially to the upper handle 20. The adjustment screw 74 also includes a knurled cylindrical knob portion 74b and a rearwardly projecting planar key flange 74c which defines an opening 74d therethrough.

An rigid restraining element 76 in the form of an elongate loop includes a transverse lower leg 76a that extends through the slot 72 of the extension flange 70 and thereby allows the restraining element 76 to be slidably moved in the longitudinal directions established by the slot 72. An intermediate leg 76b establishes an elongate opening 76c collectively with the upper leg 76d of the restraining element 76 which is sized and configured to allow the planar key flange 74c to pass therethrough when the restraining element 76 is pivoted into cooperative engagement with the adjustment screw 74.

It will be noted that the upper and lower handle members 20, 28, respectively will be positionally restrained relative to one another when the key flange 74c and restraining element 76 are cooperatively engaged with one another as shown in FIGS. 8 and 9. However, there exists the possibility of disengagement of the key flange 74c and restraining element 76. To prevent such disengagement, it is preferred that a supplemental rigid or flexible restraining element (not shown, but of the variety as described above) be passed through the opening 74d of the key flange 74c when restraining element 76 is cooperatively engaged therewith. In this manner, the restraining element 76 will be captured between the supplemental restraining element and the cylindrical knurled knob 74b of the adjustment screw 74 which precludes the restraining element 76 from pivoting out of engagement with the key flange 74c.

It is entirely conceivable that a restraining element could be provided as an accessory element for the wrenches of the present invention when sold commercially. And, the restraining element could be provided as an integral part of the wrench, for example, by physically attaching a restraining element to the upper or lower handles 20, 28, respectively, via flexible chain, cord or the like, or via suitable hinge structures so that a restraining element is always available to the operator when the wrench is in use.

While a conventional pair of jaws associated with the locking wrenches of this invention has been shown in the accompanying drawings, they are simply representative of any opposing movable members that may be acted upon using a toggle lever according to the general principles of locking-type wrenches. Thus, the term "jaws" as used herein and in the accompanying claims should be interpreted broadly to include any opposing structural member which is otherwise associated with a locking-type wrench of the variety described previously.

Therefore, while the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.