US3422387A - Electric current power-take-off device for enclosed busway systems - Google Patents

Description

D. G. SPRIGINGS L ELECTRIC CURRENT PowER-TAKEmFF DEVICE FOR Jan. 14, 1969 ENCLOSED'BUSWAY SYSTEMS Original Fil ed June 30, 1964 Sheet INVENTORS UONHLD G. SPRlG H S BY GERHLV EI- Mafia-M3 4 ,fs M 1 m Arron/[r Jan. 14, 1969 GSPRIGWGS ET AL 3,422,387

. ELECTRIC CURRENT POWER-TAKE-OFF DEVICE FOR 7 ENCLOSED BUSWAY SYSTEMS Original Filed June 30, 1964 Sheet 2 0f 2 H INVENTORE, DOHHLD Gspmsmg BY GERFILO EZMHRTIN ATTORNEY United States Patent 3,422,387 ELECTRIC CURRENT POWER-TAKE-OFF DEVICE FOR ENCLOSED BUSWAY SYSTEMS Donald G. Sprigings, Mystic, Conn., and Gerald E. Martin, Lynchburg, Va., assignors to H. K. Porter Company, Inc., Lynchburg, Va., a corporation of Delaware Original application June 30, 1964, Ser. No. 379,137, now Patent No. 3,337,697, dated Aug. 22, 1967. Divided and this application Nov. 7, 1966, Ser. No. 592,386 U.S. Cl. 339-44 4 Claims Int. Cl. Hillr 3/06; H011 9/16; H01r 33/12 ABSTRACT OF THE DISCLOSURE This invention relates to a power-take-off device or plug for an enclosed busway system having conductor rails at the top of the enclosure, a continuous slot in the bottom of the enclosure and grounding strips on each side of the slot. The plug has a head wider than the slot, a thickness narrower than the slot, a round stern of a diameter equal to the thickness of the head, an elongated base member on the stern and a web on each side of the stem extending from the base and joining the stem. The housing consisting of these parts is longitudinally split into identical halves bolted together. Cavities in the head mount contacts spring biased outwardly and conductors are connected thereto from a cable extending through the central bore of the stern. Slots on each side of and parallel to the bore in the stem house resilient ground contacts which extend out of the stem at its juncture with the head. Bent downwardly, the dished ends of the contacts abut the conductive ground strips in the bottom of the busway and urge the plug upwardly, further biasing the power contacts against the rails. The plug is inserted through the slot in the bottom of the busway and turned 90, during which the ground contacts cam upward and inward over the bottom of the busway. Notches on the upper edges of the webs engage with formations on the busway to resist rotation of the plug once it is in its final position.

This application is a division of our pending application, Ser. No. 379,137, filed June 30, 1964, now Patent No. 3,337,697, issued Aug. 22, 1967.

This invention relates generally to enclosed trolley busway systems in which the structural support, protective housing and bus insulation are all combine-d into one thermosetting plastic enclosure, and more particularly to an improved construction of a power-take-off plug which may be connected into the busway system at any desired point along its length by insertion upwardly into the busway enclosure through a bottom slot thereof to thereby provide a positionally fixed electrical top-off for supplying current from said system for operation of a work utility.

The foregoing and other objects of our invention will become clear from a reading of the following specification in conjunction with an examination of the appended drawings, wherein:

FIGURE 1 illustrates a side elevational view of the enclosed trolley busway system which is described in detail in our above mentioned copending application and which description thereof is included herein by reference thereto;

FIGURE 2 is a vertical sectional view taken through an enclosure coupling section as would be seen when viewed along the line 22 of FIGURE 1, the showing of FIGURE 2 being on an enlarged scale;

FIGURE 3 is a view showing the busway enclosure in transverse section and the plug-in jack positioned therein "ice for taking off current from the current conducting rails, the jack appearing in this figure as an end elevational view thereof; and

FIGURES 4 to 6 are various views of the plug-in jack per se as taken along the section lines 4-4, 5-5 and 6-6 respectively of FIGURES 3, 4 and 5.

In the several figures, like elements are denoted by like reference characters.

Referring now to the drawings and more particularly to FIGURES 1 and 2, it will be observed that the trolley of the present invention is designed for use in an enclosed trolley busway system including a plurality of longitudinally extending end-to-end alined extruded enclosure sections 40 secured together by coupling sections 43, all as described more fully in our above-mentioned copending application.

As best seen in FIGURES 2 and 3 the several interconnected enclosure sections 40 which make up the trolley busway system are each generally rectangular in cross section having an upper wall 45, opposite depending side walls 46 and a pair of inwardly projecting bottom walls 47 separated by a longitudinally centrally extending slot 48 defined by the down turned spaced apart flanges 49 which form the proximate facing edges of the bottom walls 47. The sidewalls 46 are provided near their tops with longitudinally extending inwardly projecting ledges or shoulders 46' which face one another and provide physical support for the conductor rails support blocks hereinafter described. The side walls 46 and tOp Wall 45 0f the enclosure sections 40 are cut back at an angle from points on the side walls spaced somewhat upward from the bottom walls 47 so that the interior of the enclosure sections at the ends thereof are accessible from the top and sides. Punched or drilled through the side walls 46 proximate the ends thereof are apertures 50 of proper size, shape and position to have projected thereinto complementally formed buttons 51 projecting inward from the inside surface of the side walls 52 of each half of the enclosure sections coupling devices 43.

As best seen in FIGURE 2, the side walls 52, top wall sections 53 and inturned bottom walls 54 of the enclosure sections coupling devices 43 close fittingly surface engage the top, side and bottom walls of the enclosure section 40 so that the four buttons 51 of each coupling half project through the enclosure apertures 50 to interlock the ends of adjacent enclosure sections when the vertically extending flanges 55 of the enclosure coupling halves 43 are fixedly secured together by the nuts and bolts 56 projected through the aligned apertures in said flanges 55.

Extending longitudinally along and bonded downward upon the upper surface of the enclosure bottom walls 47 are flat electrically conductive strips 60 having downturned ends extending below the housing bottom walls 47. As is more particularly shown and described in our pending application aforesaid, these ends abut one another when two enclosure sections are interconnected, the abutting ends being mechanically and electrically connected to one another. The conductive strips 60 are connected to an electrical ground when the system is placed in operation and electrically ground the frame of the trolley collector, as will be subsequently seen, to thereby prevent any shock hazard to personnel utilizing system.

The busway conductor rails 63, as best seen in FIG- URE 2, are of I-shape in cross section and are slidable endwise longitudinally into and through grooved formations formed in the conductor support block 65. These grooved formations in the conductor support block are of the same general cross sectional shape as the upper half of the conductor rails 63 in that such formations have a horizontally extending open region of the same general shape but slightly larger than the upper flange 63a of the conductor rails and have a depending vertical slot portion of the same width as the web 63b of the conductor rails 63. Disposed within the conductor rail flange receiving portion of the grooved formations are resilient biasing strips 66 which hold the conductor rails 63 in stable position within the support block 65.

The conductor rail support blocks 65 are provided with longitudinally extending side flanges 65' and a longitudinally extending top rib 67 centered between a pair of similarly extending parallel ribs 68-68, the central rib 67 extending upward above the surface of the block to a greater extent than the laterally positioned ribs 68-68. The support block side flanges 65 seat upon the enclosure side walls shoulders 46 whereby the weight of the conductor rails of the system as supported by the enclosure. As best seen in FIGURE 2, the support block central rib 67 projects upward into a groove 69 formed in the underside of the enclosure top wall 45 while the lateral ribs 68 are seated against the undersurface of the enclosure top wall 45. The conductor support block 65 is fixedly held in position within the enclosure by a bonding agent 70 which securely bonds the support block central rib 67 into the enclosure groove 69 in the enclosure top wall 45.

The enclosure sections 40 may be made of any convenient length as may be the conductor rails 63, but in general standard lengths will be such that enclosure sections and conductor rails will be of the same length so that mechanical coupling of the enclosures and electrical splicing of the conductor rails may be accomplished at the same point. It is of course understood that the conductor rail splicing is effected before the aligned enclosure sections 40 are secured together by the coupling sections 43.

FIGURES 3 to 6 illustrate the plug-in jack structure of the present invention which may be connected into the busway system at any desired point by insertion upward through the enclosure bottom slot to provide a fixed position electrical tapofl. The plug-in jack unit, designated generally as 146, in generally of T-shaped configuration having a head 147 and a stem 148 from the bottom of which latter laterally extends a handle portion including a flat horizontal flange 149 and a vertical web 150 integrally formed with the lower portion of the stem 148 and the horizontal flange 149.

As best seen in FIGURES 4 to 6, the body of the plugin jack unit is formed of two identical vertically extending halves made of electrical insulating plastic material and which are secured together by the nuts and bolts 151 projected through the vertical web portions 150 of the jack handle and by the nuts and bolts 152 projected through the head portion 147 of the jack unit. The head 147 of the jack unit is formed with three vertically extending cavities 153 open at the top and bottom, and with the bottom openings communicating with a horizontally extending cavity 154 which in turn communicates with the open bottomed bore 155 extending vertically through the stem 148 from the bottom thereof.

The top and bottom open ends of the vertical cavities 153 are of smaller cross-section than the cavities themselves, the heads 156 of the conductor rails electrical contact elements 157 projecting freely upward through the top openings of the cavities 153 while the flanged portions 158 formed at the bottom of the heads 156 extend laterally thereof and are too large to move upward through the cavity top opening and thereby retain the contact elements within the cavities. Extending downward from the contact element flanges 158 are stems 159 about which are disposed helical compression springs 160 which have their upper ends seated against the underside of the flanges 158 and their lower ends seated on the bottoms of the cavities 153. The springs 160 bias the heads of the contact elements upward so that the latter are vertically resiliently shiftable. Electrically secured to and extending downward from the contact elements 157 into the cavity 154 are electrical conductors 161 which are formed into a cable 162 and extended downward through the vertical bore 155 and out of the bottom of the stem 148. The cable and conductors contained therewithin are of course terminated in any convenient manner useful for connection to a utility to be operated.

Also formed in the stem 148 and extending vertically parallel to the bore 155 on opposite sides of the latter are a pair of rectangular slots 163 which open through the bottom of the stem 148 and turn laterally outward in opposite directions at the top of the stem to merge with horizontally extending open bottomed cavities 164 as formed in the bottom of the head 147. Extending vertically upward through each of the rectangular slots 163 from a point below the bottom edge of the stem 148 is the vertical leg 165 of a spring metal grounding strip 166, the upper ends of the grounding strip vertical legs 165 when turning laterally outward into the cavities 164 and merging with angularly laterally outwardly extending legs 167 of the grounding strips 166, the outer ends of the downwardly angled legs 167 terminating in upwardly 'dished contact cups 168. As best seen in FIGURE 3, the

contact cups 168 are engaged with the enclosure grounding strips 60 when the plug-in jack unit 146 is operatively engaged with the busway system so that the externally accessible lower ends of the vertical legs 165 of the grounding strips 166 are at electrical ground potential.

As is best seen in the showing of FIGURE 4, the jack head 147 and stem 148 are of the same width, and, as best seen in FIGURE 3, this width is just slightly less than the width of the enclosure slot between the enclosure lower flanges 49. Moreover, the downward angulation of the grounding strip legs 167 of the plug-in jack unit is observed to be greater in the showing of FIGURE 5 than in the showing of FIGURE 3. This results from the fact that the distance between the underside of the dished contact cups 168 and the upper surface of the electrical contact element heads 156 is greater than the vertical distance within the enclosure 40 between the upper surface of the grounding strips 60 and the under surface of the conductor rails 63.

Consequently, when the plug-in jack is inserted upward into the enclosure 40 through the bottom slot it must be inserted sufliciently upward to cause the electrical contact elements 157 to engage the center conductor rail and be depressed downward somewhat into the plug-in jack head against the bias of the compression springs 160 in order to permit the dished contact cups 163 of the grounding strips 166 to cam upward and inward over the enclosure flanges 49 as the plug-in jack unit is rotated through into the position shown in FIGURE 3. Once the contact cups have been cammed up onto the flanges 49 of the enclosure 40, the plug-in jack may be pulled slightly downward by means of the handle flange 149 so that the lower ends of the enclosure flanges may clear the upper edges of the plug-in jack vertical webs and then drop into the receiving notches 169 recessed downward from the upper edges of these vertical webs 150.

The engagement of the contact element heads 156 with the conductor rails 163 causes the compression springs to tend to drive the entire plug-in jack unit 146 downward, but this drive is oflset by the resilient action of the grounding strips 166 which tend to drive the plug-in jack unit upward by reason of the engagement of the dished contact cups 168 with the enclosure grounding strips 60. The upward drive of the resilient grounding strips 166 overbiases the downward drive of the compression springs 160 so that the plug-in jack unit moves vertically upward into its stable position in which the enclosure flanges 49 are seated Within the web notches 169, the drive of the compression springs 160 insuring a good contact between the heads of the electrical contact elements and the above lying conductor rails 63.

Having now described our invention in connection with particularly illustrated embodiments thereof, it will be appreciated that modifications and variations thereof may now occur from time to time to those persons normally skilled in the art without departing from the essential scope or spirit of our invention, and accordingly it is intended to claim the same broadly as well as specifically as is indicated by the appended claims.

What is claimed to be new and useful is:

1. A current collector plug-in jack device for use in conjunction with a conductor system which includes a plurality of laterally spaced longitudinally extending conductor rails having downwardly facing contact surfaces housed within an enclosure having a pair of longitudinally extending bottom walls defining therebetween a central longitudinally extending slot of substantially constant width, comprising in combination,

(a) a main body of insulating material having a head part of a transverse Width greater than and of a thickness less than said slot whereby said head may be projected upwardly through said slot and then rotated through 90 degrees to dispose it transversely of said slot and the conductor rails in said housing, said head part being formed with a plurality of vertical recesses laterally spaced for respective registry with said rails,

(b) a spring-pressed electrical contact element disposed within each of said recesses and projecting upwardly above the upper surface of said head part for resilient engagement with one of the said conductor rails when said plug-in jack is in operative position within the aforesaid enclosure,

(c) a stem part depending from said head part for projection downwardly through said slot and terminating in a handle portion disposed externally of said housing, said handle portion being adapted to underlie the bottom walls of said enclosure, and

(d) a pair of spring-pressed elements extending laterally from opposite sides of said stem part in underlying relation to said head part adapted to resiliently seat upon the bottom walls of the enclosure and thereby bias said head part upwardly in said enclosure and effect respective engagement of said contact elements with said conductor rails when said head part is inserted into and rotated within the enclosure as hereinbefore set forth.

2. A current collector plug-in jack as defined in claim 1 wherein said handle portion of the stem part limits upward movement of the jack into said enclosure and wherein said handle portion and said enclosure are provided with coacting interlocking means for preventing unintentional rotation of the plug relatively to said enclosure upon operative final engagement of the contact elements with the conductor rails.

3. A current collector plug-in jack as defined in claim 2 wherein said laterally extending spring-pressed elements respectively terminate in dished extremities which cam over the bottom walls of the enclosure as the jack is rotated into operative position.

4. A current collector plug-in jack device for use in conjunction with an enclosed conductor system, which system includes enclosure sections of hollow generally rectangular cross section formed of electrical insulation material having a top wall below which are disposed a plurality of side by side parallel extending spaced apart conduetor rails having downwardly facing contact surfaces, a pair of depending side walls which turn inwardly toward one another at their bottom edges to form a pair of longitudinally extending bottom walls defining therebetween a central longitudinally extending slot of substantially constant width, and which bottom walls carry on their upper surfaces conductive grounding strips coextensive with the length of the enclosure, said plug-in jack device comprising in combination,

(a) a generally T-shaped body of insulating material having a head part and a stem part from the bottom of which latter laterally extends a handle portion including a fiat horizontal flange part and a vertical web part integrally formed with the lower portion of the stem part, said head part being formed with a plurality of laterally spaced vertically extending cavities each of which opens at the top through the upper surface of said head,

(b) an electrical contact element disposed within each of said laterally spaced head cavities and being resiliently upwardly biased by spring means contained within said cavities so that said electrical contact elements project upward above the upper surface of said head part, each of said electrical contact elements having electrically connected thereto an insulated electrical conductor extending downward therefrom into and through said stern part, said electrical contact elements being laterally spaced so as to each contact one of the above-lying conductor rails when said plug-in jack is in operative position within the aforesaid enclosure system, and

(c) a pair of spring elements extending laterally from opposite sides of said stem part and underlying the oppositely projecting portions of said head part, each of said spring elements terminating in an upwardly dished contact cup, the contact cups of the laterally spaced spring elements being separated by a distance approximately equal to the lateral spacing between the longitudinal center lines of the bottom walls of the said enclosure sections, the spring metal elements of said plug-in jack and the resilient biasing means associated with the electrical contact elements of said head part being effective to firmly drive the plug-in jack electrical head contact elements and spring metal elements into positive engagement respectively with the enclosed conductor rails and the conductive grounding strips in the enclosure bottom walls, said webs which form a part of the aforesaid handle portion of said plug-in jack being provided with means which interfit with the slit defining bottom wall portions of said enclosure eifective to mechanically stabilize said plug-in jack and maintain the same in operative position within the enclosure.

References Cited UNITED STATES PATENTS 2,279,383 4/1942 Von Gehr 191-23 2,348,665 5/1944 Von Gehr 339-21 FOREIGN PATENTS 854,276 1/ 1940 France. 1,288,609 2/1962 France.

RICHARD E. MOORE, Primary Examiner.

PATRICK A. CLIFFORD, Assistant Examiner.

US. Cl. X.R. 33921, 196

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