Abstract:
A die set for crimping operations includes first and second die members having raised areas including a plurality of knurls and character areas. The die set combining knurls and character areas on the operative areas of the die members allows a single die set to be used to condition a surface for crimping operations as well as crimping connectors and marking them with relevant indicia without having to change die sets.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Application No. 61/787,449, filed Mar. 15, 2013, the contents of which are hereby incorporated by reference in their entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to a crimp die set. More particularly, the present invention relates to a crimp die set having a surface including knurls and characters and methods of using the same. Still more particularly, the present invention relates to a crimp die set that prepares a surface to be crimped and embosses an identification number thereon. 
       BACKGROUND OF THE INVENTION 
       [0003]    Crimping tools using interchangeable accessory dies are known in the art. As will be appreciated by one of ordinary skill in the art, crimp die sets are used in various fields for various purposes. One particularly applicable field involves those environments when crimping is required for grounding metal surfaces. Such environments include grounding steel “I”-beams in construction and steel supports for solar panels in solar farms. Other environments include situations such as grounding steel street grates or steel ladders in sewer manholes, etc. Typically, these environments involve metal substrates having thicknesses of ⅛ inch to ⅞ inch. To these metal substrates, a grounding connector and grounding wire are crimped together. The composite is then adapted to take ground fault energy and the like from the substrate through the connector to the wire and then safely to ground. 
         [0004]    For these types of environments, the art has developed particularized crimp die sets and methods. For example, when installing electrical connectors and ground wires to metal substrates, it is particularly imperative that the materials stay connected even under stress or otherwise the ground fault protection is lost. To this end, Underwriter&#39;s Laboratories has promulgated the UL467 Standard for grounding connectors that specifies a minimum “pull off” value. As will be appreciated, the pull off value is the amount of stress (pounds) that is required to pull the grounding member off of the metal substrate. By requiring a minimum pull off value be met, UL-approved products can help assure that grounding wires and the like stay attached to the metal substrates through the range of stresses that may be encountered in the environment, thereby maintaining the protection against ground faults. 
         [0005]    The art generally recognizes that structural steel and other flat surfaces are often generally smooth in texture. A problem with smooth surfaces is that it is difficult to simply squeeze a connector onto the smooth surface and expect it to remain adhered under even minimal stress. To combat this adhesion problem, the art uses “knurling” dies to condition the surface of the metal substrate. “Knurling” dies are a set of dies that include a field of raised features that will deform the surface(s) of substrate under pressure to leave the surface(s) textured. Typical, the knurls (raised features) are pyramidal in shape. Knurling leaves the surface textured and thus able to form more meaningful and lasting connections when crimped together with other materials. Knurling is carried out using a crimp tool that is loaded with right and left die members (a die set). Once loaded, the crimp tool is positioned such that its jaws accept the connection area of the substrate and then operated to squeeze the metal substrate under force (up to 12 tons) between the die members. The die members in turn displace and deform the metal substrate surface with an imprint of the topography of the die member faces. Dies come in different sizes and shapes and each configuration has its own “die number.” The die number is specific to the die set and is a universally recognized classification system for dies. 
         [0006]    Notably, the connectors to be crimped to the metal substrates have been tested by UL to meet the pull off value requirement. The die index number for the die set used with the connector in passing the tests that are required for UL approval plays an important role. In order to comply with the standard, the same die number must be used in the field when crimping the connectors to substrates (to assure that the minimum pull off value is achieved). 
         [0007]    In connection with complying with the UL standard, the instructions for most electrical connectors identify the die index to be used in crimping the connectors to the metal substrate. An issue arises when an electrical inspector is inspecting a work site and needs a way to identify if the connections are complying with the UL standard by employing the correct die index. Presently, the art has evolved to the use of a second die set having a mirror-image impression of the die index number in the face of the die members. The provision of the die number recesses in the die members allows the crimp tool to be reloaded with the second die set and activated a second time to squeeze the metal, typically copper, connectors such that the second die set members deform the metal to the point that it is accepted into the impressions during crimping, thereby embossing the die number raised and visibly discernible on the connector body after crimping. An inspector can then visually see the die index number and confirm that the correct die set was used in crimping the grounding connector and wire to the metal substrate sufficient to meet the UL standard during his inspection. 
         [0008]    As will be appreciated, the current state of the art of crimp tool dies for grounding operations uses two separate die sets to perform the crimping operation. The first die set is used to prepare the surface. The second die set in turn crimps the connector to the surface and embosses a die index number thereon. The process of loading the crimp tool with a first die set to condition the surface of the substrate and engaging the substrate, then removing the tool from the substrate, loading a second die set, repositioning the tool and a connector/wire assembly, and then crimping the connector/wire assembly and substrate together (and leaving a visible die index number on the surface) is time consuming. 
         [0009]    Additionally, as will be appreciated, the cost of knurling dies and separate die index dies is expensive as an installer must purchase two crimp die sets for each crimp size, thereby increasing costs and inventory. Not only is additional time required to conduct the crimp operation in switching between the two different crimp die sets, an improper size second die set can accidentally be used, thereby resulting in a poor crimp. 
         [0010]    The foregoing highlights some of the problems with conventional crimp die sets. Furthermore, the foregoing highlights the long-felt, yet unresolved need in the art for a crimping method that can be used more quickly and efficiently to meet the requirements for crimping operations in the field. In addition, the foregoing highlights the inventor&#39;s recognition of a need in the art for a crimp die set that prepares a crimping surface and embosses an identification number thereon. 
       SUMMARY OF THE INVENTION 
       [0011]    Various embodiments of the present invention overcome various of the aforementioned and other disadvantages associated with prior art crimp die set and methods, and offers new advantages as well. 
         [0012]    According to one aspect of various embodiments of the present invention, there is provided a crimp die set that reduces inventory. 
         [0013]    According to another aspect of various embodiments of the present invention, there is provided a crimp die set that quickens a crimping operation. 
         [0014]    According to yet another aspect of various embodiments of the present invention there is provided a single crimp die set or a pair of dies that both prepares a crimp surface and embosses an identification number thereon. 
         [0015]    These aspects and other advantageous features of various embodiments of the present invention may be realized by the provision of what the present inventor terms a “combocrimp” die set. In a preferred embodiment, the combocrimp die set comprises a pair of cooperating die members adapted to fit in and be operable with standard-sized crimp tools. 
         [0016]    Preferably, the die members comprise a first die member and a second die member having operative surfaces including knurls. In preferred embodiments, the die members are configured in the same shape and comprises the same materials as prior art die members with the difference being confined to the knurl surface. According to an advantageous feature of this embodiment of the invention, the knurls are disposed in a generally waffle-pattern (similar to that of existing knurl dies) that further includes areas of numbers, symbols, or patterns defined in the knurl area. 
         [0017]    Preferably, the areas of numbers, symbols, or patterns comprise raised areas of appropriately shaped knurl peaks suited to emboss the numbers, symbols, or patterns on a substrate, such as an electrical connector and ground wire assembly, crimped between the die members. In a presently preferred embodiment, the peaks of the raised areas are coterminous with the peaks of the knurls. An advantageous feature of the invention is that the raised areas can be included on one, or preferably both, die members. In an alternate embodiment, the raised areas may comprise depressed areas similar to those of prior art crimping dies to emboss die index numbers on connectors. 
         [0018]    The invention as described and claimed herein should become evident to a person of ordinary skill in the art given the following enabling description and drawings. The aspects and features of the invention believed to be novel and other elements characteristic of the invention are set forth with particularity in the appended claims. The drawings are for illustration purposes only and are not drawn to scale unless otherwise indicated. The drawings are not intended to limit the scope of the invention. The following enabling disclosure is directed to one of ordinary skill in the art and presupposes that those aspects of the invention within the ability of the ordinarily skilled artisan are understood and appreciated. 
         [0019]    As used in this application, the terms “front,” “rear,” “upper,” “lower,” “upwardly,” “downwardly,” and other orientational descriptors are intended to facilitate the description of the exemplary embodiment of the present invention, and are not intended to limit the structure of the exemplary embodiment of the present invention to any particular position or orientation. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    Various aspects and advantageous features of embodiments of the present invention will become more apparent to those of ordinary skill when described in the detailed description of a preferred embodiment and reference to the accompany drawing wherein: 
           [0021]      FIG. 1  is a side elevational plan view of a conventional crimp tool; 
           [0022]      FIG. 2  is a perspective view of a first die set, or knurling die set, used with the crimp tool of  FIG. 1  to prepare a surface for crimping; 
           [0023]      FIG. 3  is a perspective view of a second die set used with the crimp tool of  FIG. 1  to crimp a connector to the prepared surface and emboss the die index number thereon; 
           [0024]      FIG. 4  is a top plan view of a first die of a combocrimp die set in accordance with an exemplary embodiment of the present invention; 
           [0025]      FIG. 5  is a side elevational view of the first die of  FIG. 4 ; 
           [0026]      FIG. 6  is a top plan view of a second die of the combocrimp die set in accordance with an exemplary embodiment of the present invention; and 
           [0027]      FIG. 7  is a side elevational view of the second die of  FIG. 6 . 
       
    
    
       [0028]    Throughout the drawings, like reference numerals will be understood to refer to like parts, components and structures. 
       DETAILED DESCRIPTION 
       [0029]    While the present invention will be described in connection with embodiments suited for the operation of crimping copper electrical connectors and wires to steel substrates using a hand-operated, hydraulic crimp tool, it will be readily apparent to one of ordinary skill in the art armed with the present specification that the present invention can be modified and applied to any suitable crimping operating or the like in any suitable environment. 
         [0030]    For context, a crimp tool and crimping dies commonly used in installing electrical connectors is depicted in  FIGS. 1-3 . As shown in  FIG. 1 , a conventional crimping tool  10  includes a frame  12 , a working head  14 , a pump  16 , a motor  18 , a battery  20 , a fluid reservoir  22  and a controller  24 . The tool can also include additional or alternative components. The frame  12  forms a ram hydraulic drive conduit system. The working head  14  comprises a frame section  28  and a ram  30 . The frame section  28  is stationarily connected to the front end of the frame  12 , but could be rotatable. The ram  30  is movably connected to the section  28 . The section  28  and the ram  30  are adapted to removably receive conductor knurling and crimping dies at a conductor receiving area  32 . 
         [0031]    The ram  30  moves forward and backward axially as indicated by arrow  34 . The ram hydraulic drive conduit system is connected between the pump  16  and the rear end of the ram  30 . Hydraulic fluid pumped by the pump  16  against the rear end of the ram  30  causes the ram  30  to move forward. A spring (not shown) returns the ram  30  to its rearward home position when hydraulic fluid pressure is released. The ram  30  moves a distance  31  between its rear position and its forward position. 
         [0032]    The frame  12  forms a handle  36 . The battery  20  is removably connected to the bottom of the handle  36 . The handle  36  includes two user actuatable control triggers  38  and  39 , which are operably coupled to the controller  24 . 
         [0033]    The motor  18  is coupled to the controller  24  and the battery  20 . The motor  18  is controlled by the controller  24 . The output shaft of the motor  18  is connected to the pump  16  by a gear reduction or gearbox. 
         [0034]    When crimping an electrical wire crimp connector to a surface, a two step process is required. First, the surface  41 , such as a steel or solid surface area, is disposed between a first die set  42  and  43 , known as “knurling dies”, as shown in  FIG. 2 . The first die set  42  and  43  has knurls to prepare the surface  41  for the subsequent crimp connection. 
         [0035]    As shown in  FIG. 3 , the first die set  42  and  43  is removed and replaced with a second die set  44  and  45 , or “crimping dies.” The prepared surface  41  is disposed in a crimp connector  46  such that both surfaces of the prepared surface  41  engage a surface of the crimp connector  46 . An electrical wire  47  is disposed in an opening  48  in the crimp connector  46 . The surface  41 , the crimp connector  46  and the electrical wire  47  are crimped together using the second die set  44  and  45 . The second die set  44  and  45  include recesses in the form of the die index number for the die set. The recesses serve to emboss the die index number on the crimp connector  46  to ensure proper tooling was used in the operation as required by UL. 
         [0036]    As clear from the above, the accepted method of crimping grounding connectors and the like in the field is a multi-step process. In particular, the need to change die sets in mid-operation to ultimately emboss the die index number on the connector is particular time-consuming, and apt to lead to mistakes wherein an improper size second die set is accidentally be used, thereby resulting in a poor, non-compliant crimp. 
         [0037]    The present inventor recognized a need in the art for an improved process for crimping. A crimp die set, referred to as the “combocrimp” die set, in accordance with an exemplary embodiment of the present invention is shown in  FIGS. 4-7 . Although the present invention will be described with reference to the exemplary embodiment shown in  FIGS. 4-7 , it should be understood that the present invention can be embodied in alternative embodiments. For example, any suitable size and shape for the dies can be used. One of ordinary skill in the art armed with the present specification can modify the configuration of the die members to suit them for their intended purpose. 
         [0038]    Returning to the Figures, the combocrimp die set comprises first and second die members  51  and  52  that are adapted to be removably mounted to the frame section  28  and the ram  30  at opposing locations  42  and  44  of the conventional crimp tool  10  depicted in  FIG. 1 . The two locations  42  and  44  form die mounting areas of the crimp tool  10  for removably mounting the dies  51  and  52  to the crimp tool. The dies  51  and  52  can be mounted to any suitable type of tool such as, but not limited to, a non-battery operated tool or a non-hydraulic tool. The first and second dies  51  and  52  are each preferably unitarily formed as a single piece and are made of steel as with prior art die members. However, any suitable material or fabrication method may be used, and such variations are well within the ability of one of ordinary skill in the art. 
         [0039]    The first die  51  of the combocrimp die set is shown in  FIGS. 4 and 5  and has a substantially semi-cylindrical shape. A rounded surface  53  of the first die  51  is received at location  42  of the crimp tool  10  of  FIG. 1 . A planar surface  54  of the first die  51  has a raised platform  55 , which is spaced inwardly from edges  56 - 59  of the first die  51 . 
         [0040]    The raised platform  55  includes a plurality of knurls  60  and reference character areas  61 . The knurls  60  are preferably substantially pyramid shaped, although any suitable shape can be used. As shown in  FIG. 4 , the reference character  61  is “1105.” The reference character preferably corresponds to a recommended die index number for the crimp connector. 
         [0041]    As depicted, the reference character area  61  comprises raised ridges in the pattern of the reference character “1105.” With this configuration, the raised ridges serve to condition the surface as well as stamp the surface with the character. In alternate embodiments, the character areas  61  may comprises recesses defined by knurls (or the absence thereof). For example, knurls may surround the areas thereby defining a character. Alternatively, the raised platform  55  may include an etched area defining the character for embossing the character on a substrate. 
         [0042]    The second die  52  of the crimp die set is shown in  FIGS. 6 and 7  and has a substantially semi-cylindrical shape. A rounded surface  62  of the second die  52  is received at location  44  of the crimp tool  10  of  FIG. 1 . A planar surface  63  of the second die  52  has a raised platform  64 , which is spaced inwardly from edges  65 - 68  of the second die  52 . 
         [0043]    Similar to the first die member, the raised platform  64  of the second die member preferably includes a plurality of knurls  69  and reference character areas  70 . The knurls  69  are preferably substantially pyramid shaped, although any suitable shape can be used. As shown in  FIG. 6 , the reference character  70  is “1105.” As depicted, the reference character area comprises raised ridges in the pattern of the reference character. With this configuration, the raised ridges serve to condition the surface as well as stamp the surface with the character. In alternate embodiments, the character areas  70  may comprises recesses defined by knurls (or the absence thereof). For example, knurls may surround the areas thereby defining a character. Alternatively, the raised platform  64  may include an etched area defining the character for embossing the character on a substrate. The reference character preferably corresponds to a recommended die index number for the crimp connector and corresponds to the reference character of the first die  51 . 
         [0044]    A pair of posts  71  extend upwardly from the planar surface  63  of the second die  52  at opposite ends of the second edge  66 . The posts  71  are engaged by an edge  73  of the surface  41  to facilitate proper alignment of the surface  41 , as shown in  FIG. 2 . As shown in  FIGS. 2 and 3 , the surface  41  is one leg of a substantially L-shaped bracket  83 . 
         [0045]    To crimp the connector  46  to the surface  41  of the bracket  83 , the first and second dies  51  and  52  are connected to the crimp tool  10  in any suitable manner. The surface  41  is then disposed between the first and second dies  51  and  52 , and the crimp tool  10  is operated, as shown in  FIG. 2 , for the surface preparing step. The knurls  61  and  69  displace material on opposite surfaces of the surface  41  to prepare the surface for the crimping step. The reference characters  62  and  70  of the first and second dies  51  and  52  further displace material on the surface  41 . 
         [0046]    The prepared surface  41  is then disposed in a crimp connector  46  to which an electrical wire  47  is loosely connected, as shown in  FIG. 3 , for the crimping step. The first and second die sets  51  and  52  remain in the tool  10  for the crimping procedure. The knurled areas of the surface  41  facilitate having the crimp connector  46  crimped thereto. Operating the crimp tool  10  crimps and secures the connector  46  and electrical wire  47  and crimps and secures the connector  46  and the surface  41  of the substantially L-shaped bracket  83 . The entire raised platforms  55  and  64  of the first and second dies  51  and  52  act as the crimping surface during the crimping step. The reference characters  62  and  70  of the first and second dies  51  and  52  emboss the reference characters onto surfaces of the crimp connector  46 . Preferably, the reference characters  62  and  70  correspond to a recommended die index number displayed on the crimp connector  46 . Accordingly, during an inspection, it can be quickly and easily determined whether the appropriate die set was used by comparing the embossed characters crimped onto the connector with the recommended die index number displayed thereon. 
         [0047]    In accordance with an exemplary embodiment of the present invention, the same die set can be used to prepare the surface for crimping and for crimping the connector to the prepared surface. The inventory of required crimp die sets is reduced, and the ease and speed with which the crimping operation can be performed is increased. 
         [0048]    While advantageous embodiments have been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the scope of the invention. The above embodiments are for illustrative purposes and are not intended to limit the scope of the invention or the adaptation of the features described herein to particular tools. Those skilled in the art will also appreciate that various adaptations and modifications of the above-described preferred embodiments can be configured without departing from the scope and spirit of the invention. Therefore, it is to be understood that, within the scope of the appended claims, the invention may be practiced other than as specifically described.