US 3302160 A
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1957 E. J. NIELSEN SEGMENTED ELECTRICAL TERMINAL STRIP Filed May 6, 1964 WWW Wil
United States Patent 3,302,160 SEGMENTED ELECTRICAL TERMINAL STRIP Erik J. Nielsen, Mequon, Wis, assignor t Square D Company, Park Ridge, Ill., a corporation of Michigan Filed May 6, 1964, Ser. No. 365,286 3 Claims. (Cl. 339-198) This invention relates in general to segmented electric terminal strips and more particularly to a segmented terminal strip having an improved insulating barrier between adjacent terminal segments or blocks when blocks of various sizes are intermixed in a row to form the terminal strip.
A terminal strip comprising a plurality of individual terminal blocks interlocked with each other in a row is described in Van Valkenburg and Nielsen Patent No. 2,981,922 which issued on April 25, 1961, to the assignee of the present invention. The individual terminal blocks of the Van Valkenburg and Nielsen terminal strip include projections and recesses which cooperate respectively with complementary recesses and projections of adjacent terminal blocks to hold the terminal blocks in close transverse alignment when loosely mounted in a row on a channel and clamped between end clamps. Such terminal blocks further include integral upstanding barrier portions which serve to electrically isolate the metal connectors or connector assemblies of adjacent terminal blocks from each other when the terminal blocks are all of the same size.
A problem is encountered, however, when terminal blocks like those of the aforementioned patent are of different sizes and are intermixed in a row to form a composite terminal strip. This is because opposite end portions of the metal connectors or connector assemblies of the larger terminal blocks project beyond the side boundaries of the barrier portions of the smaller terminal blocks thus reducing the electrical clearance below an acceptable minimum. A possibility thus exists that electrical conductors fastened to the metal connectors or connector assemblies of the terminal blocks may make physical contact with each other or that conductive material may inadvertently fall across the space between the metal connectors.
This problem is not adequately solved by positioning, between adjacent small and large terminal blocks of a segmented terminal strip, a separate barrier member having recesses on one side and projections on the other which cooperate with respective complementary projections and recesses on the adjacent terminal blocks. Such a barrier member must necessarily be of substantial thickness in order to permit the recesses to be of sufficient depth. In order not to unduly lengthen a composite terminal strip made up of terminal blocks of various sizes, it is desirable to have the barrier members of relatively negligible thickness. This is accompanied, in accordance with this invention, by providing an insulating barrier member of relatively thin, rigid, insulating material of good dielectrical properties having two openings complementary to the projections of the terminal blocks with which it is to be used. The projections on one terminal block pass through the openings in the barrier member and enter the recesses of an adjacent terminal block of a different size. Such an insulating barrier member can be made much thinner than prior barrier members and still provide adequate insulation between the ends of the connectors or connector assemblies of adjacent blocks and be held securely in interlocked relation with the remainder of the terminal strip.
An object of the present invention is to provide an electrical terminal strip composed of a plurality of individual terminal blocks of various sizes intermixed in a row and having an improved insulating barrier disposed between adjacent terminal blocks of difllerent sizes.
A more specific object is to provide a terminal strip comprising a plurality of terminal blocks of various sizes interlocked with one another against transverse movement when clamped in a row between end clamps and having an improved insulating barrier between adjacent terminal blocks of dilferent sizes, which barrier can be made thinner than prior barriers and still be interlocked against transverse movement from the row by the interlocking means of the adjacent terminal blocks and which permits the adjacent terminal blocks also to be interlocked.
Further objects and features of the invention will be readily apparent to those skilled in the art from the specification and appended drawings illustrating certain preferred embodiments, in which:
FIGURE 1 is a perspective view of an improved insulating barrier member in accordance with this invention;
FIGURE 2 is a top plan view of a composite terminal strip including the barrier member of FIGURE 1;
FIGURE 3 is a side view of a portion of the terminal strip of FIGURE 2;
FIGURE 4 is an exploded perspective view of the terminal strip of FIGURE 2; and
FIGURE 5 is a perspective view of one of the terminal blocks of FIGURE 2 showing the projections.
An insulating barrier member 10 in accordance with the present invention is shown in FIGURE 1. The barrier member 10 is preferably made of a phenolic material having a reinforced base, such as. cotton fiber, so as to have adequate dielectric properties, rigidity, and resistance to chipping or fracture although extremely thin when compared to prior barrier members. The importance of these characteristics will become apparent hereinafter.
The barrier member 10 has a generally rectangular slot 11 extending downwardly from the center of its super edge. Projecting inwardly from opposite side walls of the slot 11 is a pair of scored nibs 12. A pair of horizontally elongated, generally rectangular openings 13 with rounded end portions extend through the barrier member 10 in horizontally spaced relation to each other, and a generally T-shaped slot 14 extends upwardly from the bottom edge of the barrier member lltl.
The barrier member 10 is positioned in the segmented terminal strip 24} of FIGURE 2. The terminal strip 20 comprises a plurality of individual. terminal blocks 21 of relatively large size intermixed in a row along a T-shaped mounting channel 22 with a plurality of individual terminal blocks 23 of size smaller than the size of the terminal blocks 21 in both height and width. The larger terminal blocks 21 are necessary in certain applications to accommodate electrical connectors of adequate size for higher current levels. In other instances, and as shown, the larger terminal blocks 21 are necessary to accommodate composite electrical connectors or connector assemblies 24 including a pair of fuse retainers 25 for fuses (not shown) which fuses would be too large to be carried by the smaller terminal blocks 23. In the embodiment shown, the barrier member 10 is interposed between a terminal block 21a of the plurality of larger terminal blocks 21 and an adjacent terminal block 23a of the plurality of smaller terminal blocks 23.
The individual terminal blocks 21 and 23 are preferably constructed of a molded phenolic material. Each of the larger terminal blocks 21 has an integral barrier portion 26 extending upwardly from one side of a base portion 27. A pair of horizontally elongated, generally rectangular projections 28 (best seen in FIGURE 5) extend in horizontally spaced relation from the outer face of the barrier portion 26 and a pair of recesses 29 shaped and positioned to receive the respective projections 28 of an adjacent terminal block 21 are provided in the face of the base portion 27 opposite the barrier portion 26. A rectangular slot 30 extends downwardly from the center of the top edge of the barrier portion 26 and a generally T-shaped slot 31 extends upwardly from the bottom face of the base portion 27. A composite electrical connector or connector assembly 24 comprising a pair of the fuse retainers 25 is provided on each of the terminal blocks 21 for mounting a fuse. Each of the fuse retainers 25 comprises spaced blade or clip portions 25a extending upwardly from a conductive bar 25b having a screw terminal 250 at an outer end thereof. Each fuse retainer 25 is suitably held within spaced slots 34 formed in the upper surface of the base portion 27. Each of the screw terminals 250 receives a conductor (not shown) to complete a circuit through a fuse received between the pairs of the blades 25a of a composite connector 24.
Each of the smaller terminal blocks 23 has an integral barrier portion 36 extending upwardly from one side of a base portion 37. A pair of horizontally elongated, gen erally rectangular projections 38 extend in horizontally spaced relation from the outer face of the barrier portion 36 and a pair of recesses 39 shaped and positioned to receive the projections 38 of an adjacent terminal block 23 are provided in the face of the base portion 37 opposite the barrier portion 36. A T-shaped slot 40 extends downwardly from the center of the top edge of the barrier portion 36 and a generally T-shaped slot 41 extends upwardly from the bottom face of the base portion 37. A projection 42 extends from the central portion of the barrier 36 in overlying spaced relation with the upper surface of the base portion 37 to define a slot 44 in which an electrical connector 45 is suitably held. Conductors (not shown) to be interconnected are fastened to respec tive screw terminals 45a and 45b at opposite ends of the electrical connector 45.
The pairs of projections 28 and 38 of the respective blocks 21 and 23 have the same dimensions so as to be able to cooperate with either of the pairs of recesses 29 and 39 of the respective blocks 21 and 23 thereby permitting the intermixing of the terminal blocks 21 and 23 in a row in any arrangement that may be desired. In assembling the composite terminal strip 20, the T-shaped openings 31 and 41 of the terminal blocks 21 and 23 are received on the mounting channel 22 as best seen in FIG- URE 4. The individual terminal blocks 21 and 23 are pressed together on the channel 22 so that the projections 28 or 38 of one of the terminal blocks 21 or 23 are received within the recesses 29 and 39 of the next adjacent terminal block 21 or 23 as the case may be. As described in the aforementioned Van Valkenburg and Nielsen patent, the row of assembled terminal blocks 21 and 23 is terminated at one end by a spacer or reversing unit 48 (FIG- URE 2) having projections complementary to the recesses 28 and 38 on both faces thereof and the blocks are clamped rigidly together on the mounting channel 22 by a pair of identical end clamps 49, each having pairs of recesses of the same size and relative position as the recesses 29 and 39. The projections 28 and 38 cooperate with the recesses 29 and 39 to hold the individual terminal blocks 21 and 23 in transverse alignment.
As best seen in FIGURE 2, a condition of relatively short electrical clearance occurs in the regions generally indicated by the numeral 50 when one of the larger terminal blocks 21, such as the terminal block 2111, is mounted adjacent one of the smaller terminal blocks 23, such as the terminal block 23a, with the projections 38 of the terminal block 23a received within the complementary recesses 29 of the terminal block 21a. The opposite ends of the electrical connector assembly 24 of the larger terminal block 21a extend beyond the barrier portion 36 of the smaller terminal block 23a in the region 50. A possibility then exists that electrical conductors when connected to the screw terminals 45a and 45b and the screw terminals 250 may make physical contact, or that conductive material may inadvertently fall across the surfaces of relatively short length between the terminals 45a and 250 and 45b and 250.
To prevent the foregoing from occurring, one of the barrier members 16 in accordance with the present invention is interposed between the adjacent terminal blocks 21a and 23a. The barrier 10 is mounted on the channel 22 by inserting the channel 22 through the T-shaped slot 14. The openings 13 align with the recesses 29 of the terminal block 21a and, as best seen in FIGURE 3, the projections 38 of the terminal block 23a pass through the respective openings 13 of the barrier member 10 and project into the respective recesses 29 of the terminal block 21a. The barrier member 10 is preferably of the same height and Width as the barrier portions 26 of the terminal block 21a so as to enclose the associated electrical connector assembly 24 in the same manner as do the barrier portions 26 of adjacent terminal blocks 21.
The barrier 10 is constructed of a phenolic material with a reinforced base so as to permit a minimum thickness for the required degree of rigidity and durability. In the present embodiment, the thickness of the barrier member 10 has been held to approximately 1 of an inch. The thickness of the barrier member 10 in the drawing is made larger than scale for clarity. The projections 38 of the smaller terminal block 23a may thus pass through the opening 13 of the barrier 10 and suitably cooperate with the recesses 29 of the larger terminal block 21a without a substantial loss of mechanical interlocking action between the adjacent terminal blocks 21a and 23a. The reinforced base of cotton fiber for the barrier member 10 permits the barrier member to be flexed without fracturing or cracking, thereby providing the required degree of durability.
A conventional marking strip (not shown) is insertable in the slots 40 of therminal blocks 23 for appropriate identification markings thereon. The nibs 12 of the barrier member 10 prevent such a marking strip from being inserted past the barrier portion 36 of the terminal block 23a thereby to permit the insertion of a fuse in the connector assembly 25 of the terminal block 21a. The nibs 12 are pre-scored for convenient removal by snapping off when a barrier member 10 is used with terminal blocks which do not mount fuses thereon and it is desired to insert the marking strip across the entire length of the composite segmented terminal strip 20.
It can therefore be seen that a barrier member 10 in accordance with the present invention provides a convenient and economical method of permitting terminal blocks of various sizes to be intermixed in a composite segmented electrical terminal strip without reducing the desired electrical clearance between the metal connectors of the terminal blocks and without substantially adding to the overall length of the terminal strip.
1. A composite segmented terminal strip comprising a plurality of terminal blocks of different sizes aligned in a row in end-to-end relation with a larger one of said blocks adjacent a smaller one of said blocks in said row, interlocking means on each of said blocks interlocking adjacent blocks thereby to align the blocks in said row and to restrict relative lateral movement of the blocks, said interlocking means for each block comprising: a base, a projection extending from one end face of the base and a complementary recess in the other end face of the base, each of the blocks having an integral barrier portion extending upwardly at one end of the base, an electrical connector mounted on each block in endwise alignment with the barrier portion of its associated block and exposed endwise from the end face of its associated block opposite the barrier portion thereof, the barrier portion of said one of the smaller blocks being next adjacent the end of said one of the larger blocks opposite the barrier portion thereof, the electrical connector mounted on said one of the larger blocks extending laterally of said r-ow beyond the barrier portion of said one of the smaller blocks, an insulating barrier member interposed in the row between said one of the larger blocks and said one of the smaller blocks to provide electrical isolation between the respective connectors thereof, said insulating barrier comprising a strip of insulating material having an opening complementary to, and aligned with, the interlocked complementary recess and projection of the blocks adjacent thereto on opposite sides thereof, and said insulating barrier being sufficiently thin to permit the projection on one of said blocks adjacent thereto to extend through the said opening and to be received in an interlocking relation within the recess of the other of said blocks adjacent thereto, a single reverseing block having a thickness substantially equal to the thickness of the barriers on said block and a pair of oppositely facing projections each substantially identical with the projections on the terminal blocks so that each projection of the reversing block can be accommodated in said cavities selectively, and thereby the reversing block may be selectively positioned at an end of the row and intermediate the ends of the row in a terminal strip when one reversing block, the plurality of terminal blocks and the insulating barrier are assembled to provide a terminal strip, and a separate clamping memher at each end of the terminal strip for maintaining said plurality of terminal blocks, said insulating barrier and said reversing block in assembled interlocked relation.
2. The terminal strip of claim 1 characterized in that each of said blocks has a slot formed in the base thereof, a common support member is received in said slots lengthwise of said row, said barrier member has a slot receiving said support member and the clamping members are secured to the support member.
3. The terminal strip of claim 1 characterized in that said insulating barrier is a rigid strip of fabric-based, phenolic material.
References Cited by the Examiner UNITED STATES PATENTS 1,926,927 9/1933 Woertz 339--l98 X 2,981,922 4/1961 Van Valkenburg et al. 339-198 2,990,534 6/1961 Nielson 339l98 3,236,975 2/1966 De Smidt et a1. 339-198 FOREIGN PATENTS 886,329 8/ 1953 Germany.
EDWARD C. ALLEN, Primary Examiner.
W. DONALD MILLER, Examiner.