Abstract:
A method for highly reliable and durable electrical power distribution and a fusing block assembly for distribution of large electric currents to electricity-consuming devices. The invention is a machined block ( 10 ) of conductive material into which threaded connectors ( 20 ) for input wires are affixed through the use of slip-joint ferrules ( 23 ) which allow the connectors ( 20 ) to be tightened securely to block ( 10 ) without twisting the wires. Threaded output connectors ( 30 ) hold fuses ( 70 ) which are joined to output wire connector assemblies ( 40 ). The output wire connector assemblies ( 40 ) also include slip-joint ferrules ( 51 ) which allow the connectors ( 40 ) to be tightened securely without twisting the wires.

Description:
TECHNICAL FIELD 
     The present invention relates generally to electrical power safety fusing devices and more particularly, to fuse holding blocks for high current electrical distribution. 
     BACKGROUND OF THE INVENTION 
     Fuses and fusible links, as well as circuit breakers, are circuit protection devices which create an open circuit for protecting a peripheral device in the event of over-current. 1  Typically, fuses are utilized in a manner such as “cartridge fuse” which contains a conductive strip coupled at the ends to fuse caps. Such fuses are usually installed in either a fuse block or a fuse panel. However, such related art fuse blocks and fuse panels are formed from an electrically insulating material and function as a mere housing for the fuses. 2  Thus, a need for an apparatus and method comprising a new fuse block formed from an electrically conductive material which accommodates power fuses, in particular, and which facilitates high current power distribution to peripheral devices is seen to exist. 
       1 Electric Utility Engineering Reference Book: Distribution Systems, Vol. 3, p. pp. 393-393, Westinghouse Electric Corporation (1965).  
       2 William H. Crouse and Donald L. Anglin, Automotive Mechanics, 10 th  Ed., pp. 343-344, Glencoe McGraw-Hill (1995).  
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is a method for highly reliable and durable electrical power distribution and a fusing block assembly for distributing large electrical currents to electrically-powered devices. The present invention apparatus is a machined distribution block of conductive material, typically metal, into which threaded connectors for input wires are affixed through the use of slip-joint ferrules which allow the connectors to be tightened securely to the distribution block without twisting the wires. Output connectors are threaded into the distribution block and are configured to securely hold tube-type fuses which are further electrically coupled to an output wire connector assembly. The output wire connector assembly also comprises slip-joint ferrules which similarly allow the connectors to be tightened securely without twisting the wires. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     For fuller understanding of the present invention, reference is made to the accompanying drawing in the following section entitled Detailed Description of the Invention. 
     FIG. 1 is a plan view of the power fuse block, in accordance with the present invention. 
     FIG. 2 is a side view of an input connector of the power fuse block, in accordance with the present invention. 
     FIG. 3 is an end view of an input connector of the power fuse block, in accordance with the present invention. 
     FIG. 4 is a side view of an output connector of the power fuse block, in accordance with the present invention. 
     FIG. 5 is an end view of an output connector of the power fuse block, in accordance with the present invention. 
     FIG. 6 is an exploded view of a wire connector assembly of the power fuse block, in accordance with the present invention. 
     FIG. 7 is a side view of the power fuse block, in accordance with the present invention. 
    
    
     Reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawings. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIGS. 1 and 7, a partially assembled power fuse block  100  is shown. The major components are the power distribution block  10 , input connector  20 , output connector  30  and wire connector assembly  40 . The electrically conductive components are constructed of compatible electrically conductive materials such as brass, stainless steel, or aluminum alloy, for example, and may be plated with non-oxidizing material such as gold or platinum for increased reliability. Also shown is tube fuse  70  comprising a glass cylinder with electrical connectors at each end and a fusible link therebetween within the glass cylinder. Power distribution block  10 , also shown in side view in FIG. 7, is a solid rectangular block of electrically conductive material, such as stainless steel, aluminum, brass, or the like. Block  10  contains one or more threaded cavities  15  for receiving the input connectors  20  and output connectors  30 . In the preferred embodiment, there are three cavities for receiving input connectors  20  and three for receiving output connectors  30 , as below described. Block  10  also contains one or more threaded cavities, not shown, for receiving screws or bolts  81  for mounting block  10  to base  80 , as shown in FIG.  7 . 
     Referring to FIGS. 2 and 3, an input connector  20  is shown. Input connector  20  has a head  21  which is faceted into a hexagonal nut. Head  21  is used to securely tighten connector  20  to block  10  during assembly of the power fuse block. Connector  20  has a threaded portion  22  which is dimensioned to match a corresponding cavity  15  in block  10 , and which serves to secure connector  20  to block  10 . One or more input connectors  20  may be used; the preferred configuration has three input connectors  20 , as shown. 
     Ferrule  23  is a hollow cylinder having a rim  26  formed inside cavity  25  which retains ferrule  23  inside connector  20  but allows it to rotate freely. An input wire, not shown, is fastened inside of ferrule  23  by a compression fit, so as to secure the wire to connector  20  but allow it to rotate relative to connector  20 . When connector  20  is threaded into cavity  15  of block  10 , ferrule  23  allows connector  20  to rotate without twisting the connected wire. Ferrule  23  is brought into intimate electrical contact with block  10  through connector  20  when shoulder  24  is tightened against block  10 . Input connector  20  is made of an electrically conductive material compatible with the material of block  10 . 
     Referring to FIGS. 4 and 5, an output connector  30  is shown. Connector  30  is formed from a single piece of electrically conductive material compatible with the material of block  10  and has two features, a threaded portion  32  and a fuse receiver  33 . Alternatively, threaded portion  32  could be left unthreaded and pressed into a matching cavity in block  10 . 
     Fuse receiver  33  is a hollow portion having a hexagonally faceted exterior and internal cavity  35  dimensioned to securely hold one end of a tube fuse. Fuse receiver  33  has an external surface faceted to accept a tool for tightening connector  30  into cavity  15  for securing connector  30  into block  10 . Expansion slots  34  allow for cavity  35  to be slightly undersized, allowing fingers  37  to flex slightly outward when a fuse  70  is inserted into cavity  35 , thereby securely holding fuse  70  in electrical contact with connector  30 . An opening  38  is bored through connector  30  between face  31  and cavity  35 . Connector  30  is inserted with face  31  first into cavity  15  of block  10  and connector  30  is securely tightened until shoulder  36  contacts the surface of block  10  by use of a tool fitting the external faceted surface of receiver  33 . 
     Referring to FIG. 6, a wire connector assembly  40  is shown. Wire connector assembly  40  consists of two components, a fuse receptacle assembly  41  and a wire terminal  50 . Fuse receptacle assembly  41  consists of a fuse receiver  43  which has expansion slots  44  and cavity  45  for receiving and holding a fuse, as above described, for the output connector  30 . Fuse receiver  43  is connected to wire receiver  47  by neck  46 , a solid piece of material. Wire receiver  47  has a threaded cavity  48  dimensioned to receive the threaded portion  53  of wire terminal  50 . Wire receiver  47  has an external surface faceted to accept a tool for tightening the fuse receptacle assembly  41  to wire terminal  50 . 
     Wire terminal  50  has a captive ferrule  51  formed and retained in cavity  52  in a manner similar to ferrule  23 , above described. Threaded portion  53  is dimensioned to screw into cavity  48 . The head  54  is formed with a faceted exterior surface for receiving a tool for tightening terminal  50  into assembly  41  at cavity  45 . Head  54  has a cavity  55  into which an output wire is inserted to allow the wire to be secured to ferrule  51 . In use, an output wire, not shown, is inserted through cavity  55  and opening  56 , then secured inside ferrule  51  by a compression fit. Ferrule  51  is free to rotate within head  54 , allowing terminal  50  to be screwed into assembly  41  at cavity  48  without twisting the output wire. 
     Referring to FIG. 7, the power fuse block is shown in side view. Block  10  is secured to insulating base  80  by screws or bolts  81 . Wire connector assembly  40  is supported in saddle  82 . A clear, insulating cover  60  is fitted over the entire power fuse block and detachably attached to base  80  to provide protection from the energized unit and yet allow a user to observe if a fuse is blown. Saddles placed to coincide with necks  46  are formed within the interior of cover  60  to aid in retaining wire connector assembly  40  in position and separated from parallel units. Gaps are formed in the perimeter of cover  60  to allow egress of the input and output wires as is known in the art. 
     Information as herein shown and described in detail is fully capable of attaining the above-described object of the invention, the presently preferred embodiment of the invention, and is, thus, representative of the subject matter which is broadly contemplated by the present invention. The scope of the present invention fully encompasses other embodiments which may become obvious to those skilled in the art, and is to be limited, accordingly, by nothing other than the appended claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” All structural and functional equivalents to the elements of the above-described preferred embodiment and additional embodiments that are known to those of ordinary skill in the art are hereby expressly incorporated by reference and are intended to be encompassed by the present claims. Moreover, no requirement exists for a device or method to address each and every problem sought to be resolved by the present invention, for such to be encompassed by the present claims. Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. However, it should be readily apparent to those of ordinary skill in the art that various changes and modifications in form, semiconductor material, and fabrication material detail may be made without departing from the spirit and scope of the inventions as set forth in the appended claims. No claim herein is to be construed under the provisions of 35 U.S.C. 112, sixth paragraph, unless the element is expressly recited using the phrase “means for.”