Abstract:
A modular assembly for mounting a plurality of fuses in electrically insulating enclosures or blocks in side by side relationship on a plane mounting surface. The assembly includes a single sidewall L-shaped fuse support and insulating enclosure and a separate end barrier wall which snap together, forming a double sidewall insulating enclosure of U-shaped cross-sectional configuration. Each L-shaped enclosure includes provisions for interlocking assembly to adjacent L-shaped enclosures. Thus, additional single sidewall enclosures can be assembled to form a block which provides complete electrical insulation for any desired number of fuses.

Description:
BACKGROUND OF THE INVENTION 
     I. Field of the Invention 
     This invention relates generally to insulating enclosures for mounting electrical devices in a side by side relationship on a plane mounting surface and specifically to a modular snap-together assembly for mounting a plurality of electrical fuses. 
     II. Description of the Prior Art 
     The use of an insulating support base and enclosure for mounting fuses or other electrical devices is old and well known in the art. Multiple fuse blocks have been integrally molded to accomodate a specific number of fuses. However, this practice creates problems for users in that they must stock a number of different blocks for each fuse size. 
     The invention disclosed in U.S. Pat. No. 3,742,413, issued to me on June 26, 1973, for a &#34;Sectional Assembly of Insulating Enclosures for Fuses&#34; overcomes many of the disadvantages associated with prior art multiple fuse blocks. It does so by providing a fuse block assembly of modular construction. Such an assembly allows an insulating block for any desired number of fuses to be built up from only two different modules. This feature greatly reduces the number of parts a user must stock for each fuse size. Although such modular configuration represents a significant advance in the art, it requires individual mounting of each modular unit on the support surface. Thus, for example, a four fuse modular block requires eight mounting screws whereas an integrally molded four fuse block requires only two mounting screws. 
     SUMMARY OF THE INVENTION 
     The present invention overcomes many of the disadvantages associated with prior art modular fuse block assemblies. It does so by providing an assembly of substantially identical single sidewall L-shaped fuse support bases and insulating enclosures and a separate end barrier wall which interlockingly snap together forming a fuse block of any desired length. The resultant fuse block is mounted on a plane mounting surface. 
     A principal object of this invention is to provide an economical and efficient fuse block assembly with no penalty in cost, performance, mounting time, or number of mounting fasteners required compared to the use of conventional integrally molded multiple-fuse blocks for mounting a plurality of fuses on a support base utilizing a modular building block principle requiring only two different elements. The present invention reduces the variety and number of fuse blocks required as compared to conventional fuse blocks. This reduction simplifies many manufacturing, stocking, sales and distribution problems. 
     It will be understood by those skilled in the art that the present invention is not limited solely to modular snap together assemblies of L-shaped support bases and insulating enclosures and separate end barrier walls for electrical fuses. The invention may be equally well applied to enclosure assemblies for other electrical devices such as electrically operated relays and electronic switches which should be separated and insulated one from the other. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The many objects and advantages of the present invention will become apparent to those skilled in the art when the following description of the best mode contemplated for practicing the invention is read in conjunction with the accompanying drawings, wherein like reference numerals refer to the same or similar elements, and in which: 
     FIG. 1 is a perspective view of the modular snap-together fuse block assembly of the invention; 
     FIG. 2 is a perspective view of a single sidewall L-shaped fuse support base and insulating enclosure; 
     FIG. 3 is a top view of the fuse support base and insulating enclosure shown in FIG. 2; 
     FIG. 4 is a perspective view of an end barrier wall; 
     FIG. 5 is an exploded end view of the fuse block assembly shown in FIG. 1; and 
     FIG. 6 is an enlarged longitudinal sectional view of the fuse support base and insulating enclosure shown in FIG. 3 as viewed through the line 6--6. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the several figures and more particularly to FIG. 1, there is shown a modular assembly 10 according to the present invention which is made from one or more single sidewall L-shaped fuse support base and insulating enclosures 12 and a separate end barrier wall 14. As best seen in FIG. 2, each insulating enclosure 12 consists of a single piece structure made of molded dielectric material having a fuse mounting base portion 16 and an integral upwardly extending sidewall portion 18. The outer lateral surface of the sidewall portion 18 is provided with a pair of spaced apart female dovetail engagement pockets 20. Mating male dovetail prongs 22 are disposed on the outer lateral surface of the base portion 16 for vertical engagement with the corresponding female dovetail pockets 20. A lateral outwardly extending tongue or ridge 24 is provided on the same surface of the base portion 16 from which the mating male dovetail engagement prongs 22 extend. A mating recess 26 is disposed in the outer surface of the sidewall portion 18 for engagement by the tongue or ridge 24. The tongue or ridge 24 and the mating recess 26 lockingly snap into registry when a pair of substantially identical L-shaped insulating enclosures 12 are assembled by engagement of the dovetail recesses 20 of one enclosure onto mating dovetail prongs 22 of another enclosure and vertical displacement of the first enclosure relative to the second until locked together. 
     Referring now to FIG. 4, it is seen that one surface of the separate end barrier wall 14 is provided with female dovetail pockets 28 which are engageable with the male dovetail engagement prongs 22 on the base portion 16 of a single sidewall L-shaped insulating enclosure 12. A lateral recess 30 is provided on the surface of the separate end barrier wall 14 provided with the female dovetail pockets 28. The recess 30 snaps into registry with the tongue or ridge 24 on the base portion 16 when the separate end barrier wall 14 is assembled with a single sidewall L-shaped insulating enclosure 12 in a manner similar to the assembly of two or more insulating enclosures 12. 
     The integral, upwardly extending sidewall portion 18 and the separate end barrier wall 14 are each provided with cutouts 32, 34, respectively, to facilitate the manual insertion and removal of a fuse such as a cartridge fuse 36 as shown in FIG. 6. Each individual L-shaped insulating enclosure 12 is provided with a pair of metallic fuse clips 38. Each fuse clip 38 is generally U-shaped and has a base portion 40 and a pair of integrally formed symmetrically opposed upwardly extending tangs 42 for both holding and electrically contacting the terminal ends 37 of the fuse 36. The base portion 40 of the clip 38 is provided with three apertures 44, 48 and 52. Aperture 44 is adapted to receive a mounting stud 46 integrally projecting from the enclosure base portion 16. Aperture 48 is adapted to receive an integrally molded upwardly extending fuse stop 50. Aperture 52 is internally threaded and adapted to receive a terminal screw 54. When the fuse clip 38 is installed on the base portion 16, the lower portion of the terminal screw 54 extends into an integrally molded, fully insulated rectangular pocket 56 disposed in the base portion 16. The base portion 40 of the clip 38 is additionally provided with a pair of longitudinally disposed, upwardly extending flanges 58 which stiffen the clip and position wire terminal lugs (not shown) when connected with the terminal screw 54. 
     Stiffening and positioning ribs, as shown at 60 in FIGS. 1, 2 and 3, may be provided for enhancing the rigidity of the integral upwardly extending sidewall portion 18 and the male dovetail engagement prongs 22, and for locating the clips 38 during assembly, with the axes of the clips aligned with the longitudinal axis of the modular L-shaped enclosure 12 as a result of engaging the outer surface of the flanges 58 extending upwardly from the base portion 40 of the clips. 
     Both the single sidewall L-shaped insulating enclosures 12 and the separate end barrier wall 14 are preferrably molded from thermoplastic rather than thermosetting insulating material. The selection of a thermoplastic material allows the ultrasonic deformation of the integrally molded upwardly extending mounting stud 46 in the form of a rivet head, as shown at 47, to positively secure the clip 38 to the base portion 16 as best shown in the cross-sectional view of FIG. 6. 
     As can be best seen by reference to FIGS. 3 and 6, the base portion 16 of each insulating enclosure 12 is provided with a pair of centrally located mounting holes 62 through which suitable fasteners 64 may be passed to hold the assembly 10 in engagement with a plane mounting surface 66. Because of the semi-rigid nature of the assembly 10, it is unnecessary to use a fastener 64 in all of the available mounting holes 62. Two or three fasteners will easily suffice to adequately mount a fuse block of modest length. 
     Some types of cartridge fuses are made in different lengths according to various amperage ratings in order to prevent placing a larger fuse than is required into a predetermined fuse block. End stops, such as the end stops 50 in the fuse block configuration of the present invention, are appropriately spaced apart so as to prevent insertion of a larger than desired fuse. Fuse support and insulating enclosures 12 provided with various distances between the fuse stops 50 may be molded in the same mold by the simple expedient of providing the mold with interchangeable inserts provided with the appropriate mold cavities for forming the fuse stops and the mounting pins 46 at the appropriate locations for accomodating cartridge fuses of various lengths. A single inventory of clips 38 is required, as the elongated pocket 56 in the block base 16 is capable of accomodating the downwardly projecting portion of the terminal attaching screw 54 within a range of positioning of the clips apart from each other. 
     From the foregoing description it will be apparent to those skilled in the art that a number of changes, adaptations, and modifications of the present invention come within the scope of the present invention, and it is intended that all such variations not departing from the spirit of the invention be considered as within the scope thereof as limited solely by the appended claims.