US 3351893 A
Description (OCR text may contain errors)
Nov. 7, 1967 T. PARRIS ETAL 7 ONE PIECE TERMINAL BLOCK 2 Sheets-Sheet 1 Filed May 23, 1966 Nov. 7, 1967 T. PARRIS ETAL 3,351,893
ONE PIECE TERMINAL BLOCK Filed May 23, 1966 2 Sheets-Sheet 2 7 INVENTOR. f0 Z5 Wm L 25 B BY 2 l *h-dh Z 6 9 Z a 4; 4 770/P/V' United States Patent 3,351,893 (ENE PIECE TERMINAL BLOCK Thomas Parris, Milwaukee, and Erik J. Nielsen, Mequon, Wis., assignors to Square D Company, Park Ridge, 111., a corporation of Michigan Filed May 23, 1966, Ser. No. 552,321 9 Claims. (Cl. 339-198) This invention relates to terminal blocks, and more particularly to a one piece terminal block, including a plurality of electrical terminal bars, wherein a terminal block of dielectric material is molded in one piece and provides a plurality of parallel compartments in which the terminal bars can be installed, respectively, subsequent to the molding operation.
The invention relates to terminal blocks for general purposes disclosed in United States Letters Patent No. 2,981,922 of H. L. Van Valkenburg, et al., issued Apr. 25, 1961, and No. 2,610,996 of William P. Rickabaugh, issued Sept. 16, 1952.
More specifically the invention is directed to the formation of certain shoulders on the block, combined with a specific shape of terminal bars such that the bars can be inserted readily in the finished block and held therein by cooperation with the shoulders without the necessity for extraneous holding or connecting parts.
A specific object is to provide a terminal block of this character in which the adjacent terminal bars are shaped and arranged in pairs such that they can be placed closely together and a suitable bolt for mounting the block on a support can be so positioned therebetween whereby the overall length of the block can be reduced.
Various other objects and advantages of the invention will become apparent from the following description wherein reference is made to the drawings, in which:
FIG. 1 is a top plan view of a terminal block embodying the principles of the present invention, part thereof being shown in section, with part of the terminal bars being broken away for clearness in illustration;
FIG. 2 is a fragmentary top plan view of the block illustrated in FIG. 2., with terminal bars installed;
FIG. 3 is a fragmentary front elevation of the structure illustrated in FIG. 2;
FIG. 4 is a front elevation of the block illustrated in FIG. 1, with the terminal bars removed;
FIG. 5 is a vertical, longitudinal, sectional view taken on the line 5-5 of FIG. 1;
FIG. 6 is a vertical, cross sectional view taken on the line 66 in FIGS. 1 and 5;
FIG. 7 is a bottom plan view of the structure illustrated in FIG. 5, one of the terminal bars being shown installed therein;
FIG. 8 is a top plan view of one of the terminal bars;
FIG. 9 is a front elevation of the bar illustrated in FIG. 8; and
FIG. 10 is a vertical, cross sectional view of the bar, taken on the line 1l 10 of FIG. 8.
Referring to the drawings, the invention is shown as embodied in a multi-circuit terminal block.
The terminal block comprises a body 1 of dielectric material, such as hard rubber or one of the synthetic organic resins, phenolic resin being an example. The material is such that it can be molded to precise dimensions and will retain its dimensional accuracy.
The body 1 is molded in one piece and, subsequent to the molding operation, terminal bars 2 are mounted therein. As hereinbefore mentioned, it is desirable that the bars be mounted in operating position in the body 1 subsequent to the molding operation, and that they be secured in operating position therein due to configuration of the body and of the bars themselves. Accordingly, the body is generally rectilinear and comprises a bottom portion 3 with integral upright barriers 4 thereon. The barriers are arranged in parallel spaced face to face relation with each other in a row extending endwise of the body, the spacing being such that terminal bars may be accommodated therebetween, one bar between, and substantially filling the space between, each pair of adjacent barriers.
The body portion 3 has upwardly open sockets 5, as shown in FIGS. 1 and 6, arranged in pairs, one pair between each two adjacent barriers. The sockets 5 of each pair are disposed in symmetrical relation to, and at opposite sides of, an upright median plane which extends longitudinally of the body 1. The body portion 3 has upwardly facing terminal supporting faces or shoulders 6 arranged in surrounding relation to the upper ends of the sockets 5. These supporting shoulders preferably are coplanar and disposed in a horizontal, transverse plane near the lower portions of the barriers 4. The adjacent inner edges of each pair are spaced apart from each other on opposite sides of the median plane.
The body 1 has an upper wall portion 8 which is positioned in spaced relation above the plane of the shoulders 6 and near the top of the barriers 4. The wall portion 8 extends generally the entire length of the body. Thus a plurality of passages or compartments 9, extending transversely of the body between the wall 8 and the shoulders 6, are provided, one such passage 9 between each two adjacent barriers 4. The passages 9 have generally parallel upright walls 10 and 11, respectively, extending upwardly from the plane of the shoulder 6 and in face to face spaced relation to each other longitudinally of the body 1 for accommodating a terminal bar therebetween in each passage.
The wall 10 is provided with a central rib or boss 12 of which the lower portion is of less width than the wall 10 in a direction transversely of the body 1. The rib 12 terminates transversely of the body an equal distance beyond the opposite sides of the longitudinal upright median plane, and in spaced relation inwardly from the adjacent inner edges of the shoulders 6.
The bottom edge of the rib 12 is positioned in spaced relation above the plane of the shoulders 6 so as to provide a hoizontal central shoulder 13 extending transversely of the body 1. The spacing of the shoulder 13 above the plane of the shoulders 6 is substantially equal to the thickness of one of the terminal bars to be installed in the associated passage 9.
The walls 10, in a direction transversely of the body, terminates in spaced relation to the lateral edges of the body and its lateral edges provide upright parallel shoulders 14 spaced equidistantly from the longitudinal median plane of the body and extending parallel thereto.
The wall 11, beginning a distance above the level of the plane of the shoulders 6 about equal to the thickness of the terminal bar 2 and continuing downwardly, is of less thickness, endwise of the body, and thus provides an overhanging downwardly facing shoulder 15.
Intermediate certain pairs of adjacent passages 9, the body is provided with vertically extending through bores 16 which extend from the bottom of the body upwardly into enlarged coaxial counterbores 16a which open through the top wall of the body. Each bore 16 and its counterbore 16a is adapted to receive amounting bolt for mounting the body on a suitable support.
The upright axes of the bore 16 lie in the upright longitudinal median plane of the body and are in spaced relation to each other endwise of the body. Transverse upright planes through the axes of the respective bores at right angles to the longitudinal median plane are disposed equidistantly between opposite faces of associated barriers 4, respectively.
In the form illustrated, wherein four terminal bars are provided, these bores 16 preferably lie in the barrier next adjacent to, but spaced from, the end barriers 4 of the bod It is to be noted that the passages 9 are arranged side by side in pairs in a row extending endwise of the body 1. The passages of each pair are arranged at opposite sides of, and in spaced relation to, the wall of an associated bore 16. These passages are disposed so that the walls 10 thereof, with the ribs 12 are at the sides of the passages 9 which are adjacent to the associated bore 16, as illustrated in FIG. 5.
Referring next to the terminal bars, each terminal bar 2 comprises an elongated strip of conducting metal which is relatively rigid and which is unsymmetrical about its own longitudinal axis which extends transversely of the body 1. As best illustrated in FIGS. 8 through 10, each terminal has a midportion 21 and two end portions 22. The end portions 22 have apertures 23, respectively, which are internally threaded to receive conventional screws 24 for fastening thereto the terminals of conductors, respectively.
Each of the end portions 22 has raised bosses 25 at opposite sides of its associated apertures 23 for cooperation with a clamp 26, as illustrated in FIG. 3, which, in turn, cooperates with the bosses 2-5 for more securely fastening conductor terminals to the terminal bar 2.
It is to be noted that the midportion 21 of each terminal bar 2 has a notch 26 at one lateral edge. A tongue 27 is provided at the other lateral edge. The notch 26 is of a length such that its end walls can engage the shoulders 14 of the wall 10 with operating clearance for constraining the installed bar from endwise movement out of its associated passage 9.
The midportion 21 is provided with an elongated slot 28 which is substantially coextensive lengthwise with the midportion 21 and which terminates in spaced relation to the apertures 23. The specific configuration of the terminal bars 2 and its advantages are best appreciated by referring to FIGS. 1 and 8 through 10, wherein the adjacent passages 9 are adjacent opposite sides of the bores 16 endwise of the body.
It is to be noted that, as to each pair of terminal bars 2 which are at opposite faces of the single barrier 4, the edges of the terminal bars in which notches 26 are provided face toward each other and toward the walls 16 of the adjacent passages 9. The tongues 27 extend outwardly away from each other toward the walls 11 of the same passages 9. This permits positioning the terminal bars 2 so that the end portions 22 are in closely spaced relation edgewise in a direction endwise of the body while the edges of the central portions forming the bottoms of the notches are spaced a sufiicient distance apart to allow for the bores 16 therebetween with adequate electrical clearance between the terminal bars 2 and bolts in the bore 16. As a result, the end portions 22 of each pair of bars can be disposed with their adjacent edges substantially at the planes of the opposite faces of their associated barrier 4, even though the bottoms of the notches 26 are far enough apart to accommodate mounting bolts therebetween of greater diameter than the thickness of the associated barrier 4.
In order to install one of the terminal bars in the body, the terminal bar is passed end first through one of the passages 9 while the bar is held in tilted position transversely, as illustrated by the bar 2 shown in dot-dash lines in FIG. 5, resulting from its having been rotated about its longitudinal axis. In this tilted position, it can be passed readily through the associated body passage 9.
The terminal bar 2, while in the tilted position illustrated in the left hand passage 9 in FIG. 5, is moved to dispose the lower edges of the end portions 22, at the tongue edge, against the shoulders 6 and to dispose the tongue 27 in position to be received beneath the shoulder 15. When in this position, the terminal bar 2 is then 4 swung downwardly to the right at the notched edge so" that the tongue 27 passes beneath the shoulder 15, the end walls of the notch 26 engage fully with the shoul der 14, and the margin of the midportion 21 at the base of the notch 26 snaps under the shoulder 13 as a result of the flexibility of the midportion 21 of the terminal bar resulting from the slot 28, and as a result of the slight resiliency of the material of the body 1. However, once in place, the terminal bar 2 is retained firmly therein. The end walls of the notch 26, by engaging the shoulders 14, prevent displacement of the terminal bar 2 endwise, transversely of the body 1. The upper marginal surface of the midportion 21 adjacent the bottom of the notch 26 engaging the shoulder 13 and the tongue 27 engaging beneath the shoulder 15 prevents movement of the terminal upwardly away from the shoulders 6. The shoulders 6, of course, prevent downward displacement of the terminal bar 2. Also, the shoulders 6, 13, 14 and 15 prevent tilting of the bar 2 in its passage 9.
If desired, by suitable tools, the bar 2 can be forced into tilted position and removed from the body for purposes of repair or replacement.
The width of the midportion 21 of the terminal bar 2, endwise of the body 1, must be properly dimensioned for the snap-fastening engagement. However, in some instances where conventional tolerances do not readily permit snap action vfor installation of a terminal bar 2, then after a terminal bar is moved into the horizontal position in its passage 9, a screwdriver or other implement may be inserted in the slot 28 and twisted, thus widening the slot 28 and thereby moving the base of the notch 26 and the tongue 27 farther apart for engagement beneath their associated shoulders 13 and 15, respectively.
As is usual in such structures, a bottom strip 30 may be disposed on the bottom of the body 1 and an indicating strip 31 disposed on the top.
Having thus described our invention, we claim:
1. A terminal block comprising a body of dielectric material having a transverse passage therethrough with side walls and open ends, and with wall portions angularly' disposed to the side Walls and adapted to be engaged by, and to support, one face of a terminal bar when the bar is disposed in operating position in the passage;
shoulder means in the passage in overhanging spaced relation to said wall portions;
a terminal bar having terminal connecting portions at its opposite ends, respectively, and said bar being disposed in, and extending endwise of, the passage and being juxtaposed at one face against said wall portions and at the other face having lateral margins juxtaposed against the shoulder means;
a slot in the portion of the bar between the connecting portions; and
said slot being elongated endwise of the bar.
2. The structure according to claim 1 wherein the body has a pair of opposite facing spaced shoulders, each facing outwardly endwise of the passage;
said bar has a notch in the midportion of one lateral margin, said notch is elongated endwise of the bar and has end walls facing toward the longitudinal midportion of the bar;
and said end walls are in engagement with said oppositely facing shoulders, respectively, and constrain the bar to fixed position endwise of the passage.
3. The structure according to claim 2 wherein the bar has a tongue portion at the midportion of the other lateral margin;
said shoulder means include shoulders at both sides of the passage, the shoulder at one side of the passage engages the lateral margin of the bar at the base of the notch, and the shoulder at the other side of the passage engages the tongue portion.
4. The structure according to claim 2 wherein said oppositely facing shoulders are adjacent the ends of the P age- 5. The structure according to claim 2 wherein the slot is substantially coextensive in length with the notch.
6. The structure according to claim 2 wherein the lateral edges of the portion of the bar disposed in the passage are in stressed engagement with the side walls of the passage.
7. The structure according to claim 2 wherein said Wall portions are coplanar, the connecting portions are wider than the passage, the longitudinal midportion of the bar fits between the side walls of the passage and beneath said shoulder means;
and the passage is of such dimension in a direction normal to said coplanar portions that the bar can be received end foremost through an end of the passage when the bar is in rocked position about its longitudinal axis.
8. A terminal block comprising a body of dielectric material and having a base and a barrier portion extending transversely of the body and outwardly from the base;
terminal bars arranged at opposite faces of the barrier,
respectively, and aligned with each other;
said bars having notches at the longitudinal midportions of their adjacent lateral margins, one notch in each bar, and each bar having connecting portions at its ends;
each of the adjacent edges of the connecting portions at the respective ends being closely adjacent the barrier at its associated end;
6 said barrier having its midportion substantially coextensive edgewise of the bars and endwise of the passages with said notches and extending outwardly from the surface of the base; and said base and midportion of the barrier having a bolt receiving passage extending entirely therethrough for accommodating a bolt for securing the body to a support.
9. The structure according to claim 8 wherein the cross section of the midportion of the barrier and size of the passage are so related to each other and to the thickness of the barrier that the minimum electrical barrier between the bars and passage is at least substantially as great as the thickness of the barrier between the adjacent connecting portions of the bars.
References Cited UNITED STATES PATENTS 20 2,221,710 11/1940 Johnson 339--19s.1 2,628,263 2/1953 iBulla 339-19841 2,811,616 10/1957 Green 3-39-1984 25 MARVIN A. CHAMPION, Primary Examiner.
R. S. STROBEL, Assistant Examiner.