Abstract:
The disclosure addresses wrenches having a portion thereof including carbon fibers. Example wrenches may have a handle portion comprising the carbon fibers; which in some cases can be formed as a part of a composite laminate structure of at least a portion of the handle. Example wrenches will often include an insert portion for engaging a bolt, nut, or similar structure. In most cases, the insert will be formed of a relatively hardened material, such as a metal, or a metal-containing, material.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a non-provisional patent application claiming priority under 35 USC §119(e) to U.S. Provisional Patent Application Ser. No. 61/889,345, filed on Oct. 10, 2013, which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to wrenches, and particularly to wrenches including a handle portion comprising carbon fibers, and an insert portion for engaging a bolt, nut, or similar structure. The insert will be formed of a relatively hardened material, and in many examples will be formed of metal, or a metal-containing material. 
     Various configurations have been proposed for manufacturing wrenches with handles or other components formed of a composite material. A difficulty in such devices is providing surfaces having characteristics suitable to engage a bolt head, nut, or similar component which can be suitably coupled to a composite structure. Proposed solutions require relatively complex structures or configurations, and many are relatively undesirable for attachment to a carbon fiber structure and/or require specific manufacturing processes for use with carbon fiber. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIGS. 1A-D  depict an example wrench in accordance with the present invention, depicted in  FIG. 1A  from a plan view, and depicted in  FIG. 1B  in vertical section along the longitudinal axis of the wrench; while  FIG. 1C  depicts a metallic insert of the wrench from a plan view; and  FIG. 1D  depicts that metallic insert in vertical section. 
         FIG. 2  depicts a set of wrenches from a perspective view, each of which is constructed in accordance with the basic description of the wrench of  FIGS. 1A-D . 
         FIG. 3  depicts an alternative configuration of a wrench in accordance with the present invention, wherein the opposing ends of the wrench extend in offset, generally parallel planar relationship to one another. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The example configurations of wrenches described herein are particularly adapted for formation with carbon fiber. In some particularly preferred embodiments, as described herein, the carbon fiber structure may be previously formed (i.e. may be a rigid laminate structure as described later herein), though the novel structures described and illustrated herein are applicable to use with the carbon fiber structure regardless of how it is formed. 
     For purposes of the present description and claims, the term “bolt object” will be used to embrace and refer to any of a bolt head (of any shape, such a 4-sided, 6-sided, etc.), a nut for a bolt (which may again have any suitable number of sides or “flats”), or any bolt head like-mechanism, having a plurality of sides which are intended to be engaged to facilitate rotation, or restriction from rotation, of the mechanism. 
     Referring now to  FIG. 1 , a block diagram  100  depicting one embodiment of a wrench assembly  105  is shown. In the embodiment of  FIG. 1 , wrench assembly  105  includes a handle portion  110  and metal inserts  120  and  160 . As depicted, wrench assembly  105  is formed from a carbon fiber laminate. The carbon fiber laminate used to form wrench assembly  105  may of varying degrees of thickness (e.g., ¼″, ⅜″, ½″, 3 mm, 6 mm, etc.), although is not limited to these examples. While the described structures are particularly applicable to box-end wrenches, as in the depicted example, the described structure and methods may also be applied to other configurations, such as spanner, combination and ratchet wrenches, though aspects described herein are particularly useful when applied to box-end wrenches. 
     In some embodiments, the carbon fiber laminate used to form wrench assembly  105  may be cut from a pre-formed sheet of carbon fiber material (e.g., a laminated substrate including carbon fibers). In one embodiment, a sheet of carbon fiber from which wrench assembly  105  is formed is comprised of orthotropic (non quasi-isotropic) laminates utilizing a twill weave at 0°/90°orientation, and may in some examples be a symmetrical and balanced laminate. An example of such material is that sold as “EconomyPlate CF Sheets” by Allred &amp; Associates of Elbridge N.Y. A textured finish may appear on both sides of a carbon fiber sheet used to form a wrench assembly, although the finish applied on one or both sides of the carbon fiber sheet (and wrench assembly) may vary by embodiment. Laminates for such a carbon fiber sheet may be composed entirely of a tough and rigid carbon reinforced epoxy matrix in some embodiments. 
     Forming handle portion  110  may be accomplished by various cutting means in different embodiments. In one embodiment, a pressurized water tool may be used to cut a carbon fiber sheet to form handle  110  (as well as apertures  115  and  155 ). In other embodiments, a laser cutting tool or mechanical cutting means may be used. Alternatively, the carbon fiber may be laid up and molded specifically in the form of the handle, through techniques known to those skilled in the art. In some cases, the handle may be laid up and molded around the insert. 
     As shown, handle  110  includes apertures  115  and  155 , which may be of different sizes in various embodiments. Aperture  115 , in the embodiment shown, defines a central opening with a plurality of recesses  119  around that central opening, i.e. extending around at least a portion of the periphery of aperture  115 . In the embodiment of  FIG. 1 , aperture  115  is formed in a way that allows metal insert  120  to be secured to handle  110 . 
     Metal insert  120  is formed, in various embodiments, using stainless steel, nickel-chromium, titanium, or any metallurgical combination that would occur to those with skill in the art. In one embodiment,  304  stainless steel may be used to form insert  120 . As shown, metal insert  120  has an external periphery that includes a plurality of teeth  117  configured to engage recesses  119  in handle  110 . In the embodiment of  FIG. 1 , metal insert  120  is secured into aperture  115  using an adhesive material (e.g., epoxy), although in other embodiments additional and/or alternative means for securing metal insert  120  may be used. In some preferred examples, the insert will be press-fit into the handle aperture; and in such embodiments the metal insert  120  and aperture  115  are cooperatively sized to provide an interference fit sufficient to maintain load on metal insert  120  within aperture  115 , and to thereby provide a frictional fit sufficient to maintain placement of metal insert  120  within aperture  115 . In some examples, the surfaces at the exterior of metal insert  120  and/or the surfaces defining aperture  115  may be roughened or otherwise adapted to enhance the frictional fit. 
     The dimensions of aperture  115  may be generally uniform across the height of the aperture in handle  110  (i.e., along a vertical axis through the center of aperture  115 ). As a result, aperture  115  may be formed by surfaces that extend generally perpendicular to the nominal plane of handle  110 . In the example of wrench  100 , where handle  110  exhibits generally flat top and bottom surfaces surrounding aperture  115 , the surfaces defining aperture  115  extend generally perpendicular to the upper and lower surfaces of handle  110  proximate aperture  115 . 
     The configuration of metal insert  120  will, in many embodiments, be complementary to the configuration as described for aperture  115 , as it will be configured to aperture  155  (for example, using teeth  117 ). Thus, teeth  117  of metal insert  120 , like the remainder of the insert, may be generally uniform in dimension in the direction of a vertical axis through aperture  155 , as discussed relative to aperture  115 . 
     The height of metal insert  120  may be substantially the same as the height of handle  110  in one embodiment, while in other embodiments, metal insert  120  may be taller than (i.e., extend beyond) handle  110 , or be shorter than handle  110  (so as to be at least to some extent recessed within the thickness of handle  110 ). 
     Additionally, while metal inserts  120 ,  160  in  FIG. 1  are shown as having a uniform vertical section, other configurations are envisioned. For example, a radially-extending ledge might be formed at either an uppermost or lowermost extent of either metal insert  120 ,  160 , the ledge configured to engage the adjacent surface of handle  110 . Engagement between such a radially-extending edge and handle  110  can either be at the nominal plane of handle  110 , or could be within a recess formed within handle  110  to receive the ledge. Other potentially non-uniformities in the vertical section of metal inserts  120 ,  160  may be implemented as may be deemed useful. 
     Metal insert  120  is configured to receive and engage a bolt head in the embodiment of  FIG. 1 . In one embodiment, aperture  115  and teeth  117  define a 12 point pattern for receiving a bolt head, and the exterior peripheral surface of metal insert  120  is configured to engage complimentarily with recesses  119 . In other embodiments, different patterns for teeth  117  may be used (e.g., a 6 point or other pattern). Metal insert  120  may also be formed with a generally uniform wall thickness in its lateral direction (i.e., perpendicular to an aperture extend through the center of aperture  115 ). In such a configuration with a uniform wall thickness, the point pattern within the insert will be found also on the exterior periphery. 
     Many configurations for the complementary engagement between the insert  120  and the handle may be envisioned. While some form of repeating features around the exterior periphery of the insert will often be desirable, in some embodiments, the repeating features might not extend all around the exterior periphery, but only in selected regions (for example, for some portion of each quadrant around the periphery). Additionally, the exterior periphery of the metal insert will not necessarily have a generally circular contour (as may be considered for the depicted example, as a circle may be drawn through the plurality of teeth extending around the periphery of metal insert  120 ), but might have, for example, a generally triangular, square, pentagonal, or other multi-sided configuration. One generally continuous exterior configuration that could be used in some examples might be a general oval periphery. The chosen shape will have some contour(s) or feature(s) that will facilitate non-rotating engagement between the insert and the handle. Additionally, while a single-piece (unitary) insert will often be desirable, a multi-element assembly for the insert may also be contemplated. Additionally, in some applications the metal insert could be configured to provide additional functionality, for example, such as providing a ratcheting mechanism between the portion engaging the handle in generally fixed relation, and the portion configured to engage the nut, bolt, etc. The handle will be formed with a contour of the aperture configured to receive and engage the exterior periphery of the insert. In many particularly preferred embodiments, the handle aperture will have a contour complimentary in both size and shape to the exterior periphery of the insert, as in the depicted example. 
     As shown, handle  110  also includes aperture  155  and metal insert  160 . Aperture  155  and metal insert  160  may have substantially the same properties (respectively) as aperture  115  and metal insert  120 , but may be smaller or larger in some embodiments. For example, in one embodiment, metal insert  120  may be fit for a ⅜″ bolt while metal insert  160  is fit for a 7/16″ bolt (in this example, apertures  115  and  155  would also be sized as necessary to accommodate their respective metal inserts). In general, a variety of patterns and sizing may be used for metal insert  120 , teeth  117 , and/or recesses  119 , and may include metric sizes, in some embodiments. 
     Referring now to  FIG. 2 , a picture of a set including a plurality of example wrench assemblies  202 A-E is shown. The wrench assembly  100  described above relative to  FIG. 1  may have some or all of the properties of the wrenches shown in  FIG. 2 , in various embodiments. Although the pictured example wrenches  202 A-E are generally flat, and have a generally rectangular profile if viewed in cross-section, other configurations are contemplated. For example, some wrenches may have handle formations that are other than flat, for example, with a bolt-engaging portion that extend is a first plane, and with a handle portion that extends generally relative to a second plane angularly disposed relative to the first plane, for example at an angle in the general vicinity of 15 degrees relative to that first plane. 
     Referring now to  FIG. 3 , therein is depicted an example wrench  300  which is not flat (i.e., the opposing ends of the wrench do not lie in a common plane). In wrench  300 , a handle  302  extends between first and second engaging sections, indicated generally at  304  and  306 . In many examples, the handle  302  will be formed as a single (or “unitary”), component with both engaging sections  304 ,  306 . Each engaging section  304 ,  306  is configured to facilitate engagement with a bolt object with a respective metal insert  312 ,  314  of a respective selected size and configuration. Each engaging section includes a respective metal inserts  312 ,  314  retained within a respective engaging aperture, each of which may be configured in accordance with the various options as described relative to wrench  100  in  FIG. 1 . 
     The engaging sections  304 ,  306  are located at opposite ends of the handle, and therefore also of the wrench  300 . A first angle  308  is formed in the structure between handle  302  and engaging section  304 , and a second angle  310  is formed in the structure between handle  302  and engaging section  306 . The magnitude of each angle  308 ,  310  may be of any selected size, though in many configurations the angles will be generally equal to one another to provide a useful symmetry to wrench  300 . Though the angles may be varied as needed to facilitate ergonomic usage or to facilitate the wrench&#39;s configuration for specific applications. The result of first and second angle  308 ,  310 , respectively, is that engaging sections  304  and  306  extend in planes that are parallel but offset from one another. While the two planes do not necessarily have to extend in parallel planes (they could extend in non-parallel, and non-common planes), offset parallel planes is a desirable configuration for many purposes. 
     As was previously described embodiments, the described configuration of wrench  300  can also be achieved either by individual layup of the handle configuration, or by using a preformed carbon fiber laminate sheet having appropriate formed bends for the desired configuration, from which the wrench handle can be cut, in a manner similar to that described earlier herein. Similarly, the handle portion can have a curved section, for example with a curve along some portion of either the longitudinal axis of the wrench or along the lateral axis of the wrench portion of the wrench. Depending on the curve desired, it may be more practical in some cases to individually lay-up the carbon fiber laminate for each handle than to cut the form from a pre-cured sheet laminate shaped with the desired curve. Additionally, even where a sheet of cured laminate is used as the source for the handle form, the otherwise rectangular cross section of the cut handle can be modified by chamfering or otherwise smoothing any undesired corners of the cut handle. 
     Although particular features have been described above, additional variations are contemplated, and the invention is not limited to the specific examples that have been set forth herein, but is defined by all of the following claims and all additional claims supported by the present specification, and all equivalents thereof.