Abstract:
A composite pliers has crossed levers, each including a non-metallic body with an exposed metal cutter blade. The pliers includes strengthening and/or retaining structure around a pivot joint which does not extend into handle portions of the levers. This structure strengthens the pivot joint and can help confine the pliers parts in the event of failure. In one embodiment, each lever has a pivot joint strengthening structure insert molded therein, the structure extending into a jaw portion of each lever and protruding from the non-metallic body to form a workpiece engagement surface, such as a cutting blade. In one form, the jaws have more than one row of teeth with adjacent rows offset from each other. When the pliers is assembled from two identical lever members, each row of teeth on one lever will face the offset row of teeth on the other lever so that the peaks of the teeth on one lever fall within the grooves between the teeth on the opposing row. A non-metallic biasing structure is used to bias the jaws of the pliers open.

Description:
BACKGROUND 
     The following relates to opposed-handle tools, such as pliers, cutters and the like, and particularly to tools formed of non-metallic materials. This has particular application to pliers, such as needlenose and lineman&#39;s pliers, of both the crimping and cutting types, which are designed for use in applications where they may be exposed to high electrical voltage or current. 
     Various types of opposed-handle tools have been available for working in applications where live current poses a danger of unpleasant shocks, or even death. Such opposed-handle tools include the types disclosed, e.g., in U.S. Pat. Nos. 5,556,150; 5,503,049; 5,484,641; 4,709,206; 4,023,450; 3,833,953; and 3,082,652. These prior composite opposed-handle tools all afford at least some degree of important electrically insulating, non-sparking and non-marring qualities. In order to withstand the forces normally applied to such tools, relatively large metal reinforcing structures are often provided that extend all the way from the workpiece engaging ends down into the handles. Such relatively large metal reinforcing structures can be undesirable in terms of electrical-sparking, weight, and manufacturing costs. 
     SUMMARY 
     An opposed-handle tool can comprise levers formed almost entirely of non-metallic material with a metal reinforcing structure embedded in the levers around the pivot joint. 
     An opposed-handle tool can further comprise a pivot mechanism passageway cooperatively formed by a first opening in the first reinforcement structure and respective second and third openings in the first and second pivot joint portions. The pivot mechanism can be inserted in the pivot mechanism passageway and used to interconnect the first and second pivot joint portions. The first opening can be sized and shaped to allow the first reinforcement structure to engage the pivot mechanism and the second and third openings can be sized and shaped to minimize engagement between the pivot joint portions and the pivot mechanism. 
     The disclosed opposed-handle tool consists of certain novel features and a combination of parts hereinafter fully described, illustrated in the accompanying drawings, and particularly pointed out in the appended claims, it being understood that various changes in the details may be made without departing from the spirit, or sacrificing any of the advantages of the disclosed opposed-handle tool. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For the purpose of facilitating an understanding of the disclosed opposed-handle tool, there is illustrated in the accompanying drawings an embodiment thereof, from an inspection of which, when considered in connection with the following description, its construction and operation, and many of its advantages should be readily understood and appreciated. 
     FIG. 1 is a perspective view of one form of the pliers described herein; 
     FIG. 2 is a perspective view of one lever of the pliers of FIG. 1; 
     FIG. 3 is an exploded perspective view of the pliers of FIG. 1; 
     FIG. 4 is an enlarged top plan view of the pliers of FIG. 1; 
     FIG. 5 is an enlarged sectional view taken along the line  5 — 5  in FIG. 4; and 
     FIG. 6 is an enlarged sectional view taken along the line  6 — 6  in FIG.  4 . 
    
    
     DETAILED DESCRIPTION 
     Referring to FIGS. 1,  3  and  4 , there is illustrated an opposed-handle tool, such as a pivotal hand tool in the nature of a plier/cutter tool  20 . The tool  20  includes a pair of elongated lever members  21  and  21 A which are substantially identical in construction. Accordingly like parts of the lever members  21  and  21 A bear the same reference numbers with the reference numbers of the lever member  21 A bearing the suffix “A” for purposes of distinguishing the two lever members. The following description will be principally with respect to the lever member  21 , and it will be appreciated that, although they may not all be specifically mentioned, the lever member  21 A has like parts. 
     Referring also to FIG. 2, the lever member  21  includes an elongated handle portion  22  at one end thereof and a workpiece engaging end, such as jaw  30 , at the other end thereof. Handle portion  22  and jaw  30  are interconnected by a reduced-thickness pivot joint portion  23 , which has a flat, planar inner surface  24  bounded at the rearward and forward ends thereof, respectively, by shoulder walls  25  and  26 . Formed through the pivot joint portion  23  is a cylindrical bore  27 , that can have a circular, or different shaped, cross-section. In one form, a slot  28  is provided proximate the end of handle portion  22  that is furthest from jaw  30 . 
     Referring also to FIGS. 5 and 6, the jaw  30  has substantially parallel side surfaces  31  and  32  interconnected by an outer surface  33 , which terminates at the forward end of the jaw  30  in a nose surface portion  34 . The side surfaces  31  and  32  are also interconnected by a serrated inner surface portion  35  which is opposite the outer surface  33  and has a plurality of transversely extending, sawtooth-shaped serrations or teeth  36  formed therein to provide a gripping surface. Serrated inner surface portion  35  can comprise two rows  37 ,  38  of sawtooth-shaped teeth  36 , wherein the teeth in each row are slightly offset from one another. 
     The lever member  21  can be of a unitary, one-piece construction, being formed of a non-metallic, non-conducting or electrically resistant composite plastic material, such as a 60% glass-fiber reinforced nylon plastic material known by the trade name GRIVORY and believed to be available through EMS-American Grilon, Inc. In one form, the lever members  21  and  21 A are formed by injection molding, but it will be appreciated that other types of molding could be used. 
     Referring also to FIGS. 2,  3 ,  5  and  6 , there are respectively fixedly secured to the pivot joint portions  23  and  23 A of lever members  21  and  21 A, as by a insert molding, two reinforcement structures, such as inserts  40  and  40 A, which are substantially identical in construction. Thus, the parts of the insert  40 A bear the same reference numerals as the like parts of the insert  40 , but with a suffix “A”, but the description will be principally in terms of the insert  40 , in the same manner as is described above in connection with the lever members  21  and  21 A. 
     In one form, insert  40  is of unitary, one-piece construction and made from steel. However, the insert can also be formed of any other suitable material. The insert  40  is disposed in the pivot joint and can be substantially parallel to the inner surface  24  thereof. Each insert  40  has a bore  42  therethrough disposed substantially congruent to the cylindrical bore  27  in the associated pivot joint portion  23  or  23 A. In one form, bores  27  and  42  both have a circular cross-section having the same axis, with the circular cross-section of bore  42  being smaller in diameter than the circular cross-section of cylindrical bore  27 . Each insert  40  can be disposed in the associated pivot joint portion  23  or  23 A so that the top of insert  40  is in the same plane as, or protrudes slightly above, inner surface  24 . 
     Each reinforcing insert  40  can be of a complex shape with one or more indentations  44 , openings and/or protrusions  45 , which can be filled, or surrounded, with the plastic material as the inserts  40  are insert molded, thereby anchoring the reinforcing insert  40  in the lever member  21  and helping to prevent pieces of the pivot joint portion  23  from breaking off in the event of an overload failure. In one form, insert  40  is sized and shaped to substantially surround the cylindrical bore  27  in pivot joint portion  23  in order to provide added strength to the pivot joint portion and does not extend any substantial amount into handle portion  22 . As illustrated in FIG. 2, insert  40  can be designed so that it does not extend into handle portion  22  at all. The various indentations  44 , openings, or protrusions  45  can be used as alignment surfaces to engage positioning surfaces (not shown) in the mold. In one form, at least two alignment surfaces are used in order to properly align insert  40  when insert  40  is insert molded. The interior of bore  42  can also be used as a third alignment surface. 
     Insert  40  can extend into jaw  30  in order to strengthen jaw  30  and/or to provide a workpiece engagement structure, such as a blade  47  of a wire cutter  49  or a wire crimper, that protrudes from the material that forms the rest of jaw  30 . In another form, insert  40  does not form a blade  47  protruding from the material that forms the rest of jaw  30 . Instead, insert  40  is not exposed to the environment when tool  20  is assembled. 
     In one form, the workpiece engagement structure can be formed from one of the positioning surfaces, such as protrusion  45 . Such protrusion  45  can be in an unsharpened state when used as a positioning surface. After insert molding, the tool  20  can be assembled with the protrusions  45  and  45 A left unsharpened in order to form wire crimpers (not shown). If wire cutters are desired, the protrusions  45  and  45 A can be sharpened (before or after tool  20  are assembled) in order to form blades  47  and  47 A. 
     It is advantageous to provide at least one surface  46  on jaw  30  that slopes toward protrusion  45  or blade  47  and forms an access way to allow easier access to sharpen protrusion  45  or blade  47 . A second sloping surface  48  can be provided opposite surface  46  to allow both sides of protrusion  45  or blade  47  to be sharpened and to allow cut wire to be easily extracted from tool  20 . 
     In assembly of the lever members  21  and  21 A, they are arranged in intersecting relationship, with the pivot joint portions  23  and  23 A overlapping, with the inner surfaces  24  and  24 A in facing relationship and with the bores  27 ,  27 A,  42  and  42 A coaxially aligned. The lever members  21  and  21 A can then be pivotally interconnected by a pivot assembly  50  (FIGS.  3  and  5 ), which includes a pin  51  and two non-conducting caps, such as plastic heads  52  and  53 . Plastic heads  52  and  53  can further comprise a deformable plastic tube  54  and  55 . In one form, at least one barb  57  is provided on each end of pin  51  to engage the deformable plastic, thereby keeping the pin  51  and heads  52 ,  53  together. 
     A first end of pin  51  is inserted into head  52 , such as into the attached deformable plastic tube  54 , and the resulting coupling is inserted into the pivot mechanism passageway, comprising the aligned bores  27 ,  27 A,  42  and  42 A, through the tool  20 . Head  53  is then placed in position so that the second end of pin  51  can be inserted into deformable plastic tube  55  until each head  52  and  53  is held firmly against one of the outer surface of one of the lever members  21  and  21 A. Thus, the pin  51 , deformable plastic tubes  54 ,  55  and the heads  52 ,  53  cooperate to define a pivot shaft interconnecting the lever members  21  and  21 A for pivotal movement between the closed condition illustrated in FIG.  4  and an open condition illustrated in FIG.  1 . The pin  51  is inserted into heads  52  and  53  until the parts are firmly secured together while allowing substantially free pivotal movement. The heads  52 ,  53  are formed of an electrically non-conducting material, such as a suitable plastic or rubber, and they cooperate with the pivot joint portions  23  and  23 A to completely enclose the pivot assembly  50 , so that no metallic portion thereof is exposed. 
     In one form, a wear resistant shaft  56  surrounds at least one of deformable plastic tubes  54  and  55 . When assembled, the wear resistant shaft  56  engages bores  42  and  42 A, whereas other portions of the heads  52  and  53  have a small gap between them and the plastic material defining cylindrical bores  27  and  27 A that surround them. This enables the wear resistant surfaces of shaft  56  and insert  40  and  40 A to prevent excessive wear by accepting most of the frictional forces as the pliers are used. Even if heads  52  and  53  engage the plastic material defining cylindrical bores  27  and  27 A, the plastic material will wear during initial use and eventually shaft  56  and inserts  40  and  40 A will take most of the wearing forces. In a similar fashion, the pin  51  cab be made of a suitable wear resistant material and, after being inserted in heads  52  and  53 , a portion can be left exposed for engagement with inserts  40  and  40 A. 
     When the parts are thus assembled, the inserts  40  and  40 A are disposed in opposed facing relationship so that, when the jaws  30  and  30 A are closed, the outer surfaces of the inserts  40  and  40 A will be disposed in an abutting, substantially coplanar relationship. If inserts  40  and  40 A extend slightly above inner surfaces  24  and  24 A, then inserts  40  and  40 A will protect inner surfaces  24  and  24 A from wear due to friction as the tool  20  is used. Even if the outer surfaces of the inserts  40  and  40 A are coplanar with, or even recessed below, inner surfaces  24  and  24 A, the plastic material forming inner surfaces  24  and  24 A will wear down during initial use and then inserts  40  and  40 A will reduce further wear. 
     In one form, insert  40  is disposed in the pivot joint at a slight angle with respect to the rest of tool  20  or inner surface  24 , such that protrusion  45  is raised slightly above inner surface  24  and is slightly elevated from the portion of the insert near indentation  44 . When tool  20  is assembled from identical components, protrusions  45  and  45 A are slightly offset from one another such that they are not in the same plane, as seen most clearly in FIG.  6 . This allows protrusions  45  and  45 A to slide over one another, thereby allowing tool  20  to fully close. Utilizing a design that allows protrusions  45  and  45 A to overlap also allows protrusions  45  to protrude sufficiently outside the plastic material to allow material to be cut away to make a cutter, wire stripper or crimper. Even when a portion is cut away to form blade  47 , a sufficient overlap can be provided such that there is enough material exposed to allow multiple re-sharpenings of blades  47  and  47 A. 
     It will be appreciated that the teeth  36  and  36 A define cooperating gripping surfaces for gripping associated workpieces in a known manner. However, using two offset rows  37  and  38  (and  37 A and  38 A) on each lever member  21  and  21 A allows the lever members to be manufactured as identical parts without any detrimental performance. In this situation, when the identical parts are assembled into tool  20 , then teeth  36  of row  37  interlay with the teeth  36 A (not shown) of row  38 A (not shown) and the teeth  36  of offset row  38  interlay with the teeth  36 A of row  37 A (not shown), as best seen in FIG.  4 . In other words, teeth  36  in lever member  21  will lay in the gaps between teeth  36 A of lever member  21 A, and vice versa. Otherwise, if only one row of teeth  36  is used and the tool is assembled from identical lever members  21  and  21 A, then teeth  36  would contact teeth  36 A and prevent the tool  20  from fully closing. The interlaying of teeth  36  and  36 A prevents excessive wear from repeated contact between both rows of teeth, as would likely occur with conventional designs where teeth from opposite jaws contact one another when a pliers is fully closed. The interlaying of teeth  36  and  36 A also provides an exceptionally strong grip on some thin soft surfaces even as teeth  36  and  36 A become worn. 
     In one form, a channel or groove (not shown) is provided between rows  37  and  38 . Such a groove further allows the tool  20  to be closed more fully by minimizing contact between the edges of teeth  36  that are nearest the groove in lever member  21  and the edges of teeth  36 A that are nearest the groove in lever member  21 A. This prevents the edges of teeth  36  and  36 A from catching on one another and preventing the pliers from closing. 
     A biasing member  60  can be provided with tool  20  to bias jaws  30  and  30 A in the open position seen in FIG.  1 . In one form, biasing member  60  is rectangular in shaped and comprised of a suitable flexible non-metallic, non-conducting material having a memory, such as acetal. Biasing member  60  is bent into an arch and a first end  61  is inserted in slot  28  of lever member  21  and the second end  62  is inserted in slot  28 A of lever member  21 A. In one form, the slots  28 ,  28 A and biasing member  60  are sized so that a friction fit can be used to keep biasing member  60  in place. In an alternative form, slots  28 ,  28 A and ends  61 ,  62  can be designed to snap-fit in place. Neither alternative requires the use of metal fasteners. 
     Except for the pivot assembly  50  and the inserts  40 ,  40 A, the plier/cutter tool  20  has no metallic parts, being formed substantially entirely of electrically insulating, non-sparking, non-corroding materials, which are lightweight and non-magnetic. 
     From the foregoing, it can be seen that there has been provided an improved pivoting hand tool which is of simple and economical construction, and which is largely non-electrically conductive, lightweight, non-sparking, non-magnetic and corrosion resistant, while providing gripping and cutting surfaces which have strength, hardness, toughness and wear resistance. The forgoing improved pivoting hand tool provides a strengthened hand tool with cutters that can be sharpened, while minimizing the amount of metallic material used and exposed.