Single fastener electrical connector

#The invention relates to connectors for creating an electrical bond between metallic conductors that are to be mechanically fastened together, such as for grounding a metallic structure through a grounding conductor.

#Safety dictates electrical grounding of exposed metallic parts of equipment housings or frames if there is a possibility that such parts could carry a current. For example, photovoltaic arrays need to be grounded because they produce electricity and are installed outdoors, exposed to the elements. Such arrays typically comprise a number of photovoltaic modules that are assembled onto a larger mounting structure and must be bonded to each other as well as to the grounded mounting structure. Bonded is used here in the technical sense to mean permanently joined to form an electrically conductive path that ensures electrical continuity and has the capacity to safely conduct any current likely to be imposed. The frames of the individual modules and the structural members on which the modules are mounted usually are made of aluminum. The aluminum is anodized to resist corrosion but the anodic coating insulates these pieces so that simple piece-to-piece contact does not electrically bond them together.

#A common practice is to install a separate metallic grounding lug on each anodized piece. The grounding lug is mounted to the metal frame of a module by a thread-forming stainless steel screw with a star washer sandwiched between them. The grounding lug accepts a copper wire, which is forced into contact with the grounding lug by a stainless steel set screw. Thus, aside from the mounting screw, there are three parts involved in making such a bonded connection: a lug, a star washer and a set screw. U.S. Pat. No. 8,092,129 to Wiley, et al., which is incorporated by reference herein in its entirety, discloses various types of “bonding washers” that are positioned between the metallic pieces of photovoltaic modules and module supporting structures and pierce the anodic coating to create an electrical bond when the pieces are clamped together. FIGS. 33 and 34 show a grounding lug assembly for use when only one of the metallic pieces has an anodic coating, such as for bonding a ground wire to that piece. That assembly, too, has at least three parts besides the mounting screw.

#Preferred embodiments of the disclosed invention are described in detail below purely as examples, with reference to the accompanying drawing, in which:

#FIG. 1 is a perspective view of a first embodiment of the electrical connector of the invention shown assembled on a portion of a flat conductor and almost fully clamping a round conductor to the flat conductor;

#FIG. 2 is a side elevational view of the assembly of FIG. 1;

#Referring to FIGS. 1-4, a first embodiment of the electrical connector of the invention comprises a one-piece, generally U-shaped body 2 preferably made of stainless steel. Body 2 has a first leg 4, a second leg 6 and a bight portion 8 joining the legs. First leg 4 has an inner face 10, an outer face 12 and a distal portion 14 remote from bight portion 8. Second leg 6 has an inner face 16, an outer face 18 and a distal portion 20 remote from bight portion 8. Inner faces 10, 16 oppose one another and distal portions 14, 20 are spaced or can be urged apart to receive a first conductor C1 between them. Legs 4, 6 have respective holes 22, 24 that are aligned to accommodate a fastener F, such as a threaded bolt, for securing the body to a second conductor C2 with conductor Ci clamped between the legs.

#The distal portion 14 of first leg 4 preferably is curved outward as shown to provide an arcuate recess 26 on its inner face that cradles round conductor C1. Distal portion 14 may be configured to provide a cradling recess of a different shape, for example, a V-shaped recess (not shown). Knurls 27 (see FIG. 9) optionally may be formed on the inner surface of recess 26 to enhance the grip on and bond with conductor C1. Bonding with conductor Ci primarily occurs at the distal portion 20 of second leg 6 by means of two inner teeth 28 that project from the leg's inner face 16. One tooth would suffice if it makes a good electrical bond; however, at least two teeth are preferred and all teeth directly oppose the longitudinal center of recess 26, i.e., the centers of teeth 28 and the center of recess 26 lie in a common plane P1 (see FIGS. 2-4).

#Bonding with conductor C2 occurs at the distal portion 20 of second leg 6 by means of two outer teeth 30 that project from the leg's outer face 18. Teeth 30 are formed on a terminal portion 32 of leg 6 that is folded outward 180° substantially flat against the remainder of distal portion 20. Here, too, one tooth 30 would suffice if it makes a good electrical bond; however, at least two teeth 30 are preferred, the number being equal to the number of inner teeth 28. Each outer tooth 30 preferably is aligned with a respective inner tooth 28 so as to form sets of aligned, oppositely directed teeth, all of which lie in common plane P1. Thus, when fastener F is installed and tightened, the clamping force exerted by the connector on conductors C1 and C2 acts directly along common plane P1, maximizing the penetrating effect of the teeth on their respective conductors.