US1974452A - Panel board of the dead front convertible type - Google Patents

Description

sepi. 25, 1934.

f H. J. L. FRANK 'I PANEL BOARD OF THE DEAD FRONT CONVERTIBLE TYPE original Filed April 8. 1929 1o sheets-sheet 1 A TTORN st 'epL 25, 1934. Hf 1 L, FRANK 1,974,452

PANEL BOARD 0F THE DEAD FRONT CONVERTIBLE TYPE voriginal Filed April 8. 1929 1o sheets-sheet 2 JNVENTOR.

A TTORNE Y.

Sept.' 25, 1934. H L. FRANK` 1,974,452V

.PANEL BOARD OF THE DEAD FRONT CONVERTIBLE TYPE original Filed Apri1'8f1929 1o snets-sheet 3 INVENTOR.

E 2%;4 auf ff/1% j Sept. 25, 1934. H. 1 L FRANK ,974,452

PANEL BOARD 0F THE DEAD FRONT CONVERTIBLE TYPE Original Filed AprlrB, 1929 lO Sheets-Sheet 4 A TTORNEY.

Sept. 25, 1934.

-H. J. L. FRANK PANEL BOARD 0F THE DEAD FRONT CONVERTIBLE T YPE Y 1o sneetsfsheet 5 vori. .f,ina1 Filed April 8. 1929 S" linkin :a l

JNVENTOR. BY

Sept 275, 1934- H.. .1. L. FRANK f 1,974,452

PANEL BORDVOF THE DEAD FRONT CONVERTIBLE TYPE original Filed Abril 8, .1929 1o Sheets-sheet e INVENTOR.

ATTORNEY.

Sept. 25, 1934. H. J. l.. FRANK PAHL BOARD OF THE DEAD FRONT CONVERTIBLE TYPE l0 Sheets-Sheet 7 Original Filed April 8, 1929 INVEVTOR.

sept. 25, 1934.. J, FRANK 1,974,452

PANEL BOARD 0F THE DEAD YFRONT CONVERTIBLE TYPE Original Filed April 8, 1929 17.0 Sheets-Sheet 8 N Alul 11W/ENTOR-I ATTORNEY.

Sept. 25, l1934. H. J. 1..' FRANK PANEL BORD OF TH DEAD FRONT CONVERTIBLE TYPE Original Filed April 8, 1929 l0 Sheets-Sheet 9 INVENToR.. BY j am f/V ATToRNE v Sept. 25, 1934; f H, J. l.. FRANK 1,974,452

PANEL BOARD AOF' THE DEAD FRONT CONVERTIBLE TYPE originalV Filed April 8. 1929Y 1o sheets-sheet 1o ATTORNEY Patented Sept. 25,1934

PANEL BOARD OF THE DEAD FRONT CONVERTIBLE TYPE Harrison J. L. Frank, Detroit, Mich., assignor to Bulldog Electric Products Company, Detroit, Mich., a, corporation of West Virginia.

.Application April 8, 1929, Serial No. 353,343 Renewed March 18, 1933 25 Claims.

The invention of this application relates to electrical panelboards and parts thereof.

The principal object of the primary invention of this application is to sectionalize panelboards of the so-called feeder type, that is to say, one

wherein the circuits leading from the panelboard are of a large variety of electrical capacities and characteristics, in such a manner that no extravagane of space is permitted.

Sectionalizing of panelboards has been satisfactorily accomplished in connection with lighting distribution panelboards, these possessingthe enabling characteristic that the circuits leading therefrom are generally of similar capacity and nature. Because of this similarity, the problem of sectionalizing a lighting distribution 'panelboard is a relatively simple one.

However, for feeder panelboards, wherein the circuits are of widely dissimilar capacities and 20 characteristics and where an innite number of combinations must be effected, sectionalizing is not so simple a matter.

While sectionalizing a panelboard of this type is not in itself a difficult matter, harmonizing the demands of sectionalizing with the demands of space economy, and the demand of not having too many sizes and types of units, is a very difficult problem and until my solution was offered, there had been no satisfactory sectionalized panelboards of the feeder type.

It is observed at the present time that if the demands of space economy are to be ignored, sectionalizing of .feeder type panelboards could be eiected merely by cutting up a panelboard into a large number of units. This would provide large units and small units of various sizes and it would be obvious that aunit large enough to receive large circuit elements would be quite wasteful of spacev if used to receive small circuit elements.

Further, because of the fact that a feeder panelboard mustaccommodate an infinite variety of circuit capacities, circuitl characteristics, and combinations, sectionalizing such a panelboard at rst appeared impractical because of the fact that it was thought that an infinite variety of units would have to be made and carried in stock to meet various conditions. Merely to indicate the variety of circuit capacities, characteristics, etc., 50 there is presented here a table showing the various demands made upon feeder panelboards: 1. Poles-circuits may be of 1, 2, 3, 4, or 5 Y poles; l

2. Amperage capacities-circuits may be of 30,

. 60, 100,200, 400, 600, 800, 1200 Amp. etc.;

3. Voltages-circuits may be of 125, 250, 440, 575, or 660 volts;

4. Bus bar connectionscircuits may be connected in any of the following ways:

4 4 wire; 3-3 wire; 2 2 Wire; 3 qb to single rp; 60 2 p to single qb; 2 p 3-wire to 2 p 4-wire and to 2 qs 5-wire; 3-wire 110-220 volt single qs; the same with branches of 110 volt 2-wire -220 volt Z-Wire; 110-220 volt 3-wire, etc.

These merely exemplify the numerous demands 66 that must be satisfied, by feeder panelboards.

A solution of the problem of sectionalizing feeder panelboards, consistent with the demands of space economy, and the demands of manufacturing economies, insofar as the variety of units 70 to be carried is required, etc., is the principal object of the primary invention of this application.

A key .to my solution may be found in my discovery that the advantages desired may be gained by proportoning the divisions of the panelboard so that the dimensions of a panel builtgup of these divisions will be integral multiples of the greatestcommon factors of the corresponding dimensions of the divisions Without, at the same time, necessarily being integral multiples of the corresponding dimensions of the divisions themselves. In other words if the length dimension is considered by way of example, a dimension characteristic that is intimately associated with the result that an economy of space is effected will 35 be found to be this; the length of a panel Will be an integral multiple of the greatest common factor of the lengths of the divisions, and yet may not be an integral multiple of the lengths of divisions. That is to say, I establish a der. relation between the length of the panel and thegreatest common factor of the lengths of the divisions, but no such relation necessarily exists between the length of the panel and the lengths of the divisions; the relation established is to the factor and not to the division lengths.

In illustrating my invention, I have chosen, from a large variety, of units, units of the A, B, C, C1, and D type, combined to form SA, SB, SBi, SBz, SC, SCi, and SD circuit protecting divisions, and these have been chosen only by way of illustration of the many possibilities which my invention possesses.

Further, I have chosen to illustrate, as my units, units of the plug and receptacle type, or of the movable head and xed base type, and this type is chosen only by way of illustration.

Further objects of the invention are to provide novel details of construction of circuit protecting m0 units, combined in circuit-protecting-divisions to form a. sectionalized panelboard.

Other objects of the invention will presently appear upon reference to the following detailed description of a panelboard built in accordance with my invention and of units useful in forming the panelboard of my invention, the panelboard and these units being shown in the appended drawings in which Fig. 1 is a vertical longitudinal section of an A unit, on lines 1-1 of Figs. 4 and 30;

Fig. 2 is a plan view of an A unit receptacle part; y

lill

Fig. 3 is a perspective view of an A unit plug part;

Fig. 4 is a vertical section on line 4.-4 of Fig. 1;

Fig. 5 is a plan view of what may be designated an A unit fuse limiting plate;

Figs. 6 and 7 are perspective views 'of two forms 0f A unit plug contact and fuse prongs, Fig. 6 showing a cartridge fuse in place in one of the prongs; Fig. 8 is a diagrammatic plan view showing a group of three A units with the plugs thereof ganged, as they may well be, to form a 3 pole switch;

Fig. 9 is a perspective view of an A unit, whose plug is formed to permit of the insertion of a testing or other instrument into the circuit line;

Fig. 10 is a longitudinal vertical section of the unit of Fig. 9;

Fig. 11 is a perspectivevview of a detail thereof;

Figs. 12 and 13 are partial sectional views showing the operation of this portion of the device;

Figs. 14 to 18 represent diagrammatically differentarrangements of the means used with A units for preventing use of improper fuses in them.

Fig. 19 is a longitudinal vertical section through the receptacle part of a B unit, as if on line l1er-19, rig. 3o;

z Fig. 20 is a side elevation of a B unit plug;

Fig. 21 is a perspective view of a detail of construction thereof;

Fig. 22 is a side elevation of a B unit, with one of the plugs in circuit breaking relation, and

the other in circuit making relation;

Fig. 23 is a top plan view ofFig. 22; y Fig. 24 is an inside View of a B unit, rec-eptacle with the bottom guard member removed;

' diagrammatically indicated in Figs. 31 and 32.

will-be dened: A panelboard includes a panelf l and the associated mounting plate, box, etc. A' panel includes a number of circuit protecting divisions grouped in an ordered appearance fashion; the term panel may embrace all of the units in any one distributing center, or it may embrace less than all of the units in any one distribution center.

A "circuit-protecting-division includes a desired vgrouping of "circuit-protecting-elements, (fuses, switches, etc.,) capable of adequately protecting acomplete circuit, and associated with mounting and assembling body parts of insulating material, both the elements and their associated body partsbeing included in the word division. A unit is an article of manufacture including insulation blocks and circuit protecting elements, and may comprise a portion of a block of insulating material, as in the case of the D units. or one or more blocks of insulating material, (as in the ca'se of two A units combined) or portions of one or more blocks of insulating 'as a block,

Capacity is the maximum load carrying ability, in amperes, of the part under consideration. The capacity of a unit is its maximum load-carrying ability, in amperes. The capacity of a panel is equal to the sum, in amperes, of j the capacities of the. units comprising the panel.

From Fig. 31, it will be seen that the divisions shown are of assorted widths, across the bus bars, and assorted lengths along the bus bars, this beingl due principally t the different dimensions of the elements thereof. For example, where the elements are in the nature of low voltage fuses, the divisions are generally narrow, and where the elements are in the nature of high voltage fuses, the divisions are wide. Also, divisions of the 2 pole type are comparatively shorter than similar divisions of the 3 p'ole type.

It might be well to mention at this time that thev dimensional size of a fuse varies with its capacity. For example, a 60 Amp. fuse is larger in cross section than a 30 Amp. fuse and smaller than a 100 Amp. fuse, etc. Because of this, a division which can accommodate fuses up to 200 Amp. size, cannot accommodate a 400 Amp. fuse, etc., but a division which can accommodate a 400 Amp. fuse can also receive a smaller capacity fuse, provided it be equipped with fuse receiving means of the proper size, spacing, and type. The assortment of divisions shown diagrammatically in Figs. 31 and 32 will be briefly described.

The divisionreferenced SA in my design is l 11.,wide and 4X(5) long. The division referenced SD, is 11" wide and 4X(5) long. The divisions referenced SC are each 51/2 wide and 3X(3%-"-) long. The divisions referenced SCi are each 5%" wide, and 3X(3%) long. The divisions referenced SB are each 51/2" wide and 6X(71/2") long. The division referenced SB1 is 11'. wide and 2X(21/2") long. The

divisions referenced SBz" are each 5%" wide and 4X(5") long.

A characteristic of each division is its compactness, each' being substantially as compact as possible, consistent with the requirements that the elements thereof be properly insulated, support-l ed, grouped, etc., and consistent with manufacturing tolerances.

For convenience of manufacturing, the divisions can be built up of units,.and a representative selection ofunits for the divisions of Figs. 31-32 is shown in Fig.- 30 by way of example.

The SA division-may be made up of two A units, 11" x 2X each. The SD division may be made up of one D unit, 11" x 4X. The SC divisions together may be made up of one C unit, 11" x 3X, double branch type.' 'Ihe SCi divisions together may be made up of one C1 unit, 1l x- 3X, double branch type. The SB divisions may together be made up of three B units, 11 x 2X, double branch type.

each of the double branch type.

Other examples may be mentioned but are here omitted for purposes of brevity.

Each of the panels shown, therefore, includes.

the following units, all 11" wide; 2-A units, S-B units, l-C unit, 1-C1 unit; 1-D unit; or eight units in all, forming eight divisions, Fig. 31, or nine divisions, Fig. 32.

The units, together form a panel, which is enclosed in a cabinet whose gutter plates cover the side edges of the panel formed of the units, and because of this, to preserve an. ordered appearance it is not necessary that the units be all exactly 11" wide. Some may be lOl/2 wide and some 11%, for example, without disturbing the ordered appearance of the board.

Further, mounting means (not shown in Figs. 30-31) are provided and these also may be spaced at uniform distances X.

It will be observed at this time that the mounting and connection spacingX is only a fraction of the length of the shortest unit, being one-half of the A and B length, and is accordingly a fraction of the length of the shortest division.

Further, certain of the unit lengths are frac-gv tional multiples of other unit lengths, C:B, CzA, for example, due to the fact that the units and divisions are designed to be as compact as possible, notwithstanding the fact that some of the unit lengths are non-fractional multiples of other unit lengths.'Y I can eiect interchange of divisions and of units, without leaving gaps between divisions and-units, this being due to the fact that the mounting and connection spacing X is less than the unit length, and that each unit length is a non-fractional multiple of X.

Further, byvirtue of the fact that the dimensional characteristics or areas of circuit protective elements are substantially proportional rto their electrical characteristics or capacities, it will be seen that the areas of divisions, compacted to such elements, will prove to be similarly proportional to their capacities. having a certain arrangement of divisions, and consequently a certain area, will have a ycertain capacity and will always accommodate enough units to total substantially that capacity. This insures against overloading' of the feeders of a panel already installed, by rearrangement of units, and also permits utilization of the feeders, and the panel area to practically capacity, regardless of what rearrangements of divisions take place. This feature, together with Thus, a panel other features of design, permits replacement of one arrangement or group of divisions by different ones, without there being any danger of disturbing the ordered appearance of the panel, without creating odd-size gaps in the pane1,with out overloading the panel feeders, and without sacrifice of compactness of the panel as a whole.

Further, the divisions are subdivided into units, and these are combinable in various ways to form different types of divisions. For exam- `ple, a 7X division may be made of two 2X units plus one 3X unit, or of a 4X unit plus a 3X unit or of a 2X unit plus a 5X unit, etc. Or, a batch of 2X, 3X, etc., units may be grouped at one time to form 7X divisions, at another time 5X divisions, etc. Thus, where two'circuits whose divisions have a total length of let us say, 12X are to be replaced by five circuits totalling the same ca-.

pacity and also totalling 12X in length,lthe replacement can readily be effected without gaps, as will be illustrated by considering the five circuit divisions, 12X in length, being made up of three 2X units and divisions and two 3X units and divisions.

The method of laying out a sectionalzed panelboard system In order to design a manufacturing system for sectionalized panelboards, wherein all of the demands of sectionalizing are adequately and satisfactorily carried out, while retaining a satisfactory compactness for the panelboard, I adopted a novel method of laying out my system and I now describe it, since it aids in a complete understanding of my invention, although I do not now claim this method in this application.

I. First, I determined what complete-circuitprotecting divisions would have to be provided by my system. In doing this, I created the desired groupings of the circuit-protecting-elements, listing all of these desired groupings. For example, I discovered that among the groupings would be the following: 3-30 Amp. 250 V. fuses; 2-30 Amp. 250 V. fuses; 3-100 Amp.'600 V. fuses, etc.

II. E then proceeded to arrange the individual elements of each group on body parts of insulating material, to form divisions, in such a Way that each division would be as compact as possible, consistent withthe electrical and mechanical demands of insulation, strength, spacing, etc. and manufacturing tolerances. I discovered that in general, the divisions could be divided into two widths; about 51A",-and about 11, respectively. I therefore, determined to observe the following rule as regards the widths of any divisions I might` design. I maintained for the widths of the divisions, dimensions equal to integral-mul'tiples of a common factor width, and s of lengths of divisions, the lengths varying fromv about 21/2 up to about 'l1/2, with intermediate lengths, at about 3%, 5", 6%, etc.

IV. I then determined for that assortment of lengths a proximate common factor, which proved to be in my design, 1%", I, therefore,4

redesigned my divisions so that their lengths would be integral multiples of the common factor length. The lengths were found to be as follows: 21A?, 3%, 5, 61A, 'l1/2, etc.

V. For conveniencefof manufacture, and also in order to reduce the number of lengths from e.- the ve mentioned to three, I subdivided the divi- -mons into units, In certain cases, areas, were so subdivided that a number of units would form a complete division (SA) In another case, a, number of units formed a number of divisions (SB). In still another case, one'unit formed two divisions (SC-SC1). In another case, one unit formed one division (SD).

VI. I then proceeded to provide means for conl=- .r the elements of the division to the bus bars and means for mounting the units on the xed structure, usually the mounting plate. I provided threaded holes in the bus bars to receive connection screws and also provided on y the mounting plate threaded holes to receive mounting screws. I spaced the threaded holes of the bus bars and of the mounting plate on uniform spacngs equal to the common Afactor length 1%". I did this in appreciation ofthe fact that my 1 of divisions (and of units) varied, not as integral multiples of the length of the shortest division (or unit), but as integral multiples of the common factor length, and I appreciated that if the uniform spacing was chosen, not with relation to the length of the shortest division,

but with relation to the common factor length, I could accommodate, 1-with complete interchangeability, the intermediate lengths of divisions, that is those lengths which were not integral multiples of the length of the shortest division. A characteristic of vmy lay out, therefore,

.is the following relation, shown in Fig. 30.

. tolemes.

A still further relation is this: The overall length of the panel is an integral multiple of the greatest common factor of the unit lengths, and yet it is not neeesarily an integral multiple of any unit length. For example, a complete panel could be built up of 2A units, 1D unit, 1C unit,

and 3B units, in which case the panel length would be 17X. This would be an integral multiple of X (the `factor) but would not be an integral multiple of 2X (the length of the shortest unit). The same applies to a panel including all but the C unit of the panel of Fig. 30.

As an ple of the space emciency of my design, wherein 'the above mentioned relation is a characteristic, I contrast the lay out disclosed in Figures 36 and 31 with a similar capacity lay out, wherein the uniform spacing is equal to (2X) the length of the shortest division or unit, rather than. as on my design, where the uniform spacing X is one-half of the length of the shortest unit. From Figs. 30 and 31, itwill beseen that the length of the'panelboard shown is 20X or 25". Now,`i the spacing had been (2X). equal to the length of the shortest unit, I would nothave'been able to provide C or C1 units of the 3X length, but would have had to provide for these.

lengths of 4X. Accordingly, my SC, and SCi sections would be "4X long rather than. 3X

V long.i Altogether, the panel would be' 22X or 2711' long. By my design, therefore, I save 2X or 2541' on the p'anel shown whichis a saving of 'one channel.

about 10%, all due to the fact that my divisions are compact and the uniform spacing X is a fraction of the length of the shortest section and unit.

Greater savings in length result where the number of 3X and 5X sections is comparatively great.

Now having described a representative panelboard, and my layout method, l'. describe in detail two only of the units I provide, these being chosen by way of example.

In Figs. 1-5 I show an A unit; in Figs. 9-13, I also show an A unit, having a testing plug, and in Figs. 19-29, I show a B unit.

The "A unit The A unit shown in Figs. 1-5 is a plug and `receptacle type switch having a fuse therein to has a connecting opening 25 leadingout of the end of the receptacle. V

The oor of the receptacle covers the central channel and part of the side channels and shields the interior of the receptaclefrom the bus bar space, and is provided with a 'low cross-rib or barrier 26 immediately over one of the intermediate legs 21.

ceptacle. Each of these openings (23 and 24) Secured to the oor of the receptacle 20 as by screws 27 and extending from barrier 26 to the end wall beyond opening 2e and preferably bent so as to lie below opening 25 is a conducting plate or bar 28 carrying at its outer end a pair of iixed or receptacle contact iingers 29 which extend well up above the receptacle iioor but whose upper ends are considerably below the top of the walls thereof and below the inwardly projecting .shielding portions 30.

At the other end of the receptacle floor is a second bar or plate 28a, similar to plate 28, except that it is not so long, as, it overlies only Also within receptacre 20 and secured to barrier 26 as by screw 3l passing through hole 31a thereof is a strip of insulating material 32, shown. in plan in Fig. 5. This strip 32 may be designated the fuse limiting strip and is provided with a plurality of pairs of screw holes, care.- fully located, through which preventive forks or limiting members or stops 33 may be selectively attached thereto. 'These stops are shown in Fig. I as secured in holes numbered 3 and 5, Fig. 5.

The plug part 50 of the unit is of insulating material shaped to t within the upper portion of the receptacle and-is provided with a suitable hand grip 51' on its outer face, which may consist of a metal. plate tooshort to extend from one pair of iingers' 29 to the other so that when the' block 50 is inserted top down there can be no current iiow and all live parts are hidden. The edges of the plug are cut away from the edges of the plate as shown, to provide linger grip cavities 51a, Fig. 3.

The under side of plug 50 carries at each end plug contact and fuse prongs, which, for the 30 Amp. 250 V. fuse shownin Fig. l, comprise plug contacts 52, attached to plates 53 secured 150 any A unit receptacle 20, so as to be completely interchangeable with non-testing A unit plugs.

At one of its ends, the testing plug may be similar to any non-testing A unit plug 50. At its other end however, the testing plug 50T is provided with a large cavity opening to the under face of the plug and having a small opening 76 to the upper face. 'I'he conducting plate 53aT to which the fuse 58 is attached at the end containing the cavity 75 does not extend to the end of the plug 50T but projects beyond the edge of the cavity only for a short distance. The plug contact 52T, adapted to coact with a contact 29 in the receptacle 20,'is formed on a small plate 53bT secured to the plug as by screws 5401, which plate 53bT, has a vertical extension 77 extending up into cavity 75 at one end thereof, near opening 76.

Plate 53aT and the parts connected directly therewith are shown more in detail in Figs. 11, 12, and 13. To one end of plate 53aT is xed an L-shaped spring abutment 78 and back of this, one end of a exible lead 79. To the other end of lead 79 is ixed a small plate 80 provided with curved ends 81 as shown. Fixed to the end of lead 79 adjacent plate 80, is one end of a coil spring 82, whose other end is xed to the upright portion of the L-shaped abutment 78. Lead 79 and the spring 82 are of such construction as to allow the plate to be pressed firmly against part 77 of plate 53bT.

The electric connection in this form of plug,'

from. the contact 29 in one end of member 20 to the contact 29 in the other end thereof is through contact 52T to part 77, to plate 80, through lead 79 to plate 53aT, then through the fuse 58, to plate 53 and the other contact 29.

By means of this form of block and the form of bipolar instrument terminal shown in Figs. 9, 12, and 13, an instrument may be connected to the circuit line in series or disconnected therefrom without opening the circuit line or interrupting current flow therethrough.

The form of terminal shown consists of two plates of conducting material connected to the two poles of the instrument, d secured on opposite sides of a thin strip of insulating material 101 which may project a short distance beyond the ends of the plates.

When the tip of this device is inserted in opening 76 it easily separates the upper end of plate 80 from part 77, while the spring 82 holds the lower end of plate 80 in contact with part v77 until plates 100 have contacted with parts 77 and 80 respectively, thus maintaining the one circuit until the other is also completed. The reverse operation occurs upon withdrawal of the terminal, the circuit through the instrument being maintained until the parts 77 and 80 are once more in contact and the main circuit is completed.

An A unit plug is adapted to be used with any A unit receptacle to form a switch. Placing the plug in the receptacle with the fuse outward breaks the circuit and indicates that the circuit is broken, and placing it in the receptacle, with the fuse inside, completes the circuit, and indicates that fact.

It should be noted that the plug of Figs. 1-5 is identical in shape and outer dimensions with the plug shown in Figs. 9 to 11 and interchangeable therewith so that one may be substituted for the other without change and tests carried out when desired without interruption of service.

It will be observed that while parts 20 and 50 are named as receptacle and plug, they might well be termed base and head, etc.

The B unit This unit, shown in Figs. 19-29, includes two integrally formed receptacles,` and two separate plugs therefor, each receptacle and its plug forining half of a B unit. The unit is of the same dimensions as the A unit and is interchangeable therewith, as can be readily seen.

The B unit includes a cup shaped part 120 formed of suitable insulating material, and including end legs 121 and intermediate legs 122, the latter containing suitable bores 123 through which -may be passed bolts for securing the part 120 to a suitable supporting base, not shown.

The bottom of the cup shaped part is provided with three suitably spaced knockouts 124 providing means through which connection may be made between the elements inside the part and the bus bars 125, which latter are mounted in any suitable fashion on the supporting base, between legs 121 and 122, as indicated. In the drawings, one of the knockouts is removed, and a screw 56 and bushing 56a are shown as replacing that knockout.

Inside of the part 120 and at its ends, suitable terminal connecting plates 126 are mounted and to' these may be bolted lead terminals, 127. These y tacle contacts 128 lying close to the said wall and under an overhanging insulating portion 130 formed thereon. The exposed halves of the contactsv 128 are provided with protecting cover pieces 131 of insulating material. The provision o f parts 130-130 protect the normally live contacts 128 against accidental touching when .the receptacles are open.

In the central portion, the part 120 is provided with a metallic plate 135 overlying the central knockout and one of the others whereby this plate may be connected to anyone of the three bus bars over which the receptacle is to be placed. This plate 135 is provided with two sets of receptacle contacts 128a located on opposite sides of the cross center line of the part 120 and on opposite sides of the longitudinal center line thereof, so that, when the part 120 is divided into two receptacle compartments by means to be described, each will have receptacle contacts in diagonally opposite corners.

With the plates 126 and 135 in position, the part 120 is divided into two receptacles or compartments by a removable insulating wall or shield 140 slidable in guides 141 provided for this purpose. The wall 140 preferably carries also a cover piece 142 of insulating material which overlies the plates 126 and 135 so that when this wall unit, which is shown in Fig. 26, is in position, all of the live parts are guarded against accidental touching.

One of the two plugs 150 is shown in detail in Figs. 20, 21, 27, and 28 as consisting of a portion of insulating material of such size as to t and ll one of the receptacles and a suitable bail 151, therefor, is provided to aid in withdrawing the plug.

The side of the plug opposite the bail 151, is provided with depending side walls 152 which aid in piloting the plug into proper position for engagement of the plug contacts 153 carried thereby with the receptacle contacts 128, 128er. These plug contacts 153 are mounted at diagonally op- Levanta to the plug as by screws 54 passing through the block and having their heads sunk well below the upper surface, out of contact with 'hand plate 51. Plates l53 extend from near the central portion of the plug to close to the ends thereof and have the contacts 52 at their outer ends where they are in position to mate with contacts 29 of the receptacle. To their inner ends are attached fuse clips 55 for the reception of the 30 Amp. 250 V. fuses 58 for which the device is adapted. It will be observed that eachstructure 52-53-55 is considered as a plug contact and fuse prong.

With a bus bar 125 electrically connected to plate 28 by a screw 56 and a bushing 56a, extending through the center hole 56h in the i'loor of the receptacle 20 and into the bus bar hole H, as shown clearly in Fig. 1, replacing the knockout that had been in hole 56h. and with a load cable 57 secured to plate 28a by screw 57a as shown in the same gure, the connection through the fuse 58 from bar 125, to cable 57 'is made by inserting the plug 50 into the receptacle, with contacts 52 engaging contacts 29.

Fig. l shows the plate 28 connected through center hole 56h to the center bus bar 125,and cable 57 connected to plate 28a. If the plate 28 is' to be connected to the bus bar in the right hand channel, fora diierently phased`connection,-screw 56 and bushing 56a are placed through the right hand connection hole 56e, the knockou 56d at that point being removed, just as the center knockout had.been for the connection shown. If the plate is to be connected to the bus bar in the left hand channel, the unit as a whole is reversed 180, and the screw 56, passed through the hole 56o, will align with the left hand bus.

It will be observed that the two holes 56h and 56e through which screw 56 and bushing 56a may pass and which open the interior of the receptacle to the bus bar channels are normally closed, one being closed by the unremoved knockout, and the other by the bushing and screw, and this is normally true regardless of which bus bar is connected to strap 28. The knockouts, therefore close the bus bar compartments in back of the units. To complete the closure of the receptacle floor, an insulation sheet 56e is secured to the receptacle iioor at opening 23.

Fuse limiting The plifgs of various A units are constructed so as to be interchangeable, and for this reason I provide means for preventing the plugging-in of an A unit plug having a fuse of higher amperage or lower voltage into an A unit receptacle which should not receive such a fused plug and such means will now be described.

In general such means includes preventive forks 33 so mounted in the receptacle as to prevent insertion of a plug having an improper fuse. The forks are adjustable and removable and are used according to the schedule shown in Fig. 5.

The unit shown in Figs. '1 4 happens to be' arranged for the reception of a 30 Amp. 250 V. fuse, which is the smallest dimensionedsize fuse for which the unit lis adapted. As so arranged, the fuse ends are-received in clips 55 and the forks are positioned in holes 3 and 5 (Fig. 5) this spacing permitting the insertion oi' an"A unit plug having a 30 Amp. 250 V. use.

If' a plug is equipped with a 60 Amp.'250 V. fuse, the fuse ends will be .received in clips 55a (Figs. 14-15), which are so positioned on their prongs that they will be to one side of the longitudinal center line of the unit, and so that -they would engage the forks 33 if the latter were set in holes 3 and 5 for a 30 Amp. 250 V. fuse. A receptacle whose forks are spaced for a 30 Amp. 250 V. fuse could not therefore receive a 60 Amp. 250 V. fuse or any larger dimensioned size fuse. To permit the receptacle to receive a 60 Amp. 250 V. fuse, the receptacle forks would have to be placed in holes 2 and 6, as indicated.

If a plug is equipped with a Amp. 250 V. fuse (Fig. 18), the fuse ends, formed as blades, would be positioned'in the parallel blade clips 52e (Fig. 7) formed on a plate 52h having a plug 'contact 52d and a tongue 52o, the prong structure 52h, 52e, 52d, 52e, replacing the structure `52, 54, 55, of Figs. 1-4. If a plug so equipped were inserted into a receptacle intended to receive plugs having fuses of lower amperage, the forks 38 of that receptacle would engage parts of the structure 52h-52e, preventing complete insertion. To permit the receptacle to receive alOO Amp. 250 V. fuse, the forks would have to be set in holes 1-7 of plate 32, Fig. 5.

If a plug is equipped with a 200 Amp. 250 V.

fuse, referenced 60, (Figs. 6 and 16) the fuse ends 61, formed as blades, would be positioned in the parallel blade clips 62 formed on plate 52a. 'the latter having a plug contact 63, a tongue 62o, and a fuse holding screw 62a, structure 52a, etc., replacing the structure 52-55 of Figs. 1-4. If a plug so equipped were inserted into a receptacle intended to receive plugs having fuses of lower amperage, the forks 33 of that receptacle would engage parts of the structure 52a, etc., preventing complete insertion. To permit the receptacle to receive a 200 Amp. 250 V. fuse, the forks would be omitted entirely.

If a receptacle is equipped to receive a 30 Amp. 600 V. fuse (Fig. 17) the insertion of a plug having a 60 Amp. 250 V. fuse cannot be effected since the clip 55a of that plug would be engaged by the fork 33 of the receptacle.

From these examples it may be seen that the parts may be so arranged as to prevent the insertion of a plug 50 carrying a standard fuse of eitherhigher amperage value or lower voltage value than that for which the parts are set.

Gangz'ng Fig. 8 shows the possibility of grouping three A units over a common three bar arrangement to form a 3 pole SA division, similar to the 2 pole SA division of Fig. 31. It shows for example, the three A units connected to the three bus bars 125 selectively, with one of the units reversed 180 in position. 'I'he plugs of the three units are ganged to form a, 3 p'ole switch, by a plate 250, connecting the three plugs,` and connected to each of them by screws 251. This plate is so connected to the plugs by the screws that the plugs can move slightly on the plate,

4relatively to one another, to compensate for'diiculties in plugging in, and thus facilitating insertion or plugging in of the 3 pole switch.

It will be understood that the ganging principle may be applied to any division, and for example, two or more B unit plugs may be .ganged, if desired.

' its posite corners of the plugs, each being one branch of an L-shaped plate 154 secured to the plug at one end. These plates 154 are provided with suitable tapped openings by means of which fuse holding clips'or ngers 155 are bolted thereto. The tapped openings referred to are several in number and so located that several sizes of fuses may be provided for. The form shown in Figs. 20 and 27 for example, is for a fuse having a round end, while that in Fig. 28 is for a cartridge fuse having a blade end.

As it is intended that a plug carrying a fuse 156 may be placed in its compartment in reversed position when it is desired to maintain the circuit broken, means are provided to hold the `plug 150 securely in such position. This means may consist of a small plate 160 bent over one edge of the plug and having the bent over edge cut nearly across so as to providea tongue 161 having a teat 162 adapted to coact with the side wall of the receptacle 120 when the plug is reversed, and inserted.

Further, in order to provide means for testing the fuses without removing plugs 150, .openings 165 (Fig. 23) are provided through the plugs 150 from their outer to their inner faces, within the area covered by plates 154. These openings permit the insertion of contact wires or rods connected with any suitable indicator (not shown).

A means to prevent exchange of the plugs of two or more"B units is indicated in Fig. 23, in which gurethe plugs are shown as provided with slots 175 cooperating with screws 176 projecting through side walls of the receptacles. It is of course obvious that other plugs, not so slotted, could not be inserted, in such receptacleswhen the screws are in position. Other forms of projections and slots may of course be used Yto accomplish a like purpose. Y

.This case is in part a continuation of applicaton, Serial No. 175,173, led March 14, 1927, on Electric fusing devices.

Summary From the foregoing, it will be seen that there has been provided a sectionalized panelboard whose units may be provided with `means to prevent the combining with any unit of a fuse larger than the one intended to be used with that particular unit, the means being adjustable and removable so that the fuse receiving characteristics of the units may be varied as desired.

It will further be seen that there has been provided a sectionalized panelboard-having units on to which circuit protective elements, such as fuses, may be assembled and connected into or disconnected from the circuits, without danger to the operator; that is, insertion or removal of fuses into their clips can be accomplished only when the circuits through the fuses are dead. Further, the units are so constructed that fuse replacement can be effected only when the operator is remote from the live parts of the panelboard, or is completely shielded therefrom by insulation.

Further, the panelboard is so constructed that units may be readily converted to and from testlng'type from and to non-testing type, and when of the testing type, circuit testing may be carried on without interrupting or disconnecting the tested circuit.

Further, it will be observed that each unit.

while adaptable for several sizes of circuit protectiveelementsY (fuses) is only slightly larger in dimension than the largest elementl (ruse) for which it is designed, this feature causing the units to be as compact as efficiently possible.

Further, it will be observed that suitable barrier constructions between opposite polarity parts are provided, the barriers facilitating the compacting of the units, by reducing the sizes'thereof. Further, it will be observed that the panelboard is so constructed that all the desirable operations such as changing of circuits, refusing, rephasing, installing units, testing, etc., which require manipulating of the manipulable screws, etc.,in the receptacle, maybe accomplished from the front side of the panelboard.

It will further4 be observed that a wide range of convertibility is assured, even though a small assortment of units is provided, the units being combinable so as to create a great variety of divisions, as to size, capacity, number of poles, etc.

It will'further be observed that since the panelboard is ofthe sectionalized type, it possesses all of the advantages inherent to sectionalized panelboards, and that this is accomplished without sacrifice of compactness or convertibility, even though the circuit requirements are of a wide range, as necessary for power distribution contra-distinguished from lighting distribution. -Further, each unit is so constructed that the interior thereof is completely shielded from the live or bus bar space in back of the unitf either by the knockouts which had not been removed or by the screw and bushing insertedlin ahole wherein a knockout had been removed.

Further, a great degree of interchangeability is provided by the fact that A units are interchangeable with B units, etc., 'and parts of A units are interchangeable with parts of other A units, etc. Further, by virtue of the fact that the units can be connected selectively to any bus bar, convertibility is assured.

Further, the provision of the insulating plates adjacent the oor of the receptacles, combined with the overhanging portions of the receptacle walls and other insulating pieces, completely shields the live parts of the receptacles.

, Further, the various types of vunits have interchangeable, and standardized/mounting and connection details, which enhances the interi changeability and convertibility of the panelboard.

Further, by virtue of the specific type of connection and mounting means provided, interchange of units is facilitated, and may be accomplished from the front of the. panelboard, this also applying to rephasing lof the units, that is to say, `disconnecting them from the bus bars to which they had been connected and connecting them to diierent bus bars. Further, working on units, without disturbing other units, or the circuits therethrough, is readily possible.

vNow having described preferred .embodiments of my invention, reference will be had to the following claims for a determination of the scope of my invention.

'I claim:

l. In a panelboard of the class describeda plurality of spaced bus bars and a plurality of vclosely adjacent circuit protective units mounted in front of and over and connected to said bus bars, each unit having a plurality of depressions on the back thereof spaced in a manner correspondng to the spacing of said bus bars so that when a unit is placed over said bus bars, each depression will align with abus bar to form a compartment for each bus bar, and av knockout" in each depression integral with said unit', whereby any desired one ofthe knockouts may be removed to expose any desired one or more of the bus bars to the front of the unit, the knockou when in place serving as an insulating shield between a bus bar and the front side of the units, the knockouts beingaccessible from the front of the panelboard for removal.

2. In a panelboard of the class described, a plurality of bus bars; a plurality of contacts xedly mounted with respect to each of and spaced along said bars, a plurality of heads having contacts adapted to engage the xed contacts and means to mechanically connect two or more of said heads to operate in unison whereby a fganged head may be formed, said means being readily releasable from and attachable to said heads so that the latter may be operated independently or in unison interchangeably, said means when attached permitting a slight movement of a. head relative to its neighbor to compensate for diiiiculties in interengaging contacts,

front of and over said bus bars, a plurality of conducting parts disposed within said receptacle, and a plurality of manipulable parts disposed within said receptacle and selectively adapted to cooperate with one another, and with the threaded apertures, for mounting and connecting purposes, all of said parts being wholly manipulab from the front of the panelboard.

4. In a panelboard of the 'class described, a plurality of bus bars, units comprising a plurality of similarly constructed bases iixedly connected to said bus bars, and a plurality of similarly constructed removable heads, said heads being adapted toselectively and interchangeably cooperate with said bases, and means attachable to and detachable from said. units whereby undesirable interchange of heads and bases is prevented.

5. In a panelboard of the class described, three parallel, equally spaced bus bars, and a plurality of bases over and in front of said bus bars, each of said bases being provided with two holes therethrough for the reception of members adapted to contact with two of the bus bars, the holes aligning with an end and a center bus bar, and a knockout in each hole, the bases being symmetrical about the center bus bar.

6. In a panelboard of the class described, three parallel equally spaced bus'bars and a plurality of units over and in front thereof, each having end and center contacts adapted to engage the end and center bus bars, the ends of each unit being identical in shape so that the unit may be reversed 180 to permit the end contact to engage the other end bus bar, without disturbing the ordered appearance of the unit in the panelboard.

7. In a panelboard of the class described, a plurality of bus bars, units having contacts exposed to the sides thereof nearest the bus bars, and sheets of insulating material removably secured to said units to form barriers between the bus bars and the contacts or to expose said contacts to the bus bars. v Y

8. In a panelboard of the class -demribed, a plurality of bus bars, a plurality of head receiving bases in front thereof, all having substantially the same width and lengths equal to integral multiples of a predetermined common :factor length, and all having identical connection details whereby they may be interchangeably connected to said bus bars, certain of said bases being constructed to receive one wide head and certain being constructed to receive a plurality of narrower h ds, said bases and said heads comprising in ually cooperating bodies upon which vare dispsed mutually cooperating contacts, the

length, and all having identical connection details whereby they may be interchangeably connected to said bus bars, certain of said bases being constructed to receive one wide head and certain being constructed to receive a plurality of narrower heads, said bases and said heads comprising mutually cooperating bodies upon which are disposed mutually cooperating contacts, similarly sized and shaped heads being relatively interchangeable, said bases being provided with means to prevent the combining therewith of any but the head or heads which that base is intended to receive.-

l0. In a panelboard'of the class described, a plurality of closely adjacent units having remov- '.ab1e heads, a plate connected to and extending across a plurality of said heads to form a multihead switching unit, the heads being movable relatively and with respect to the plate to permit quick-switching action.

11. In a panelboard of the class described, a plurality of closely adjacent plug and receptacle units, means for mechanically connecting two or more plugs to operate in unison as a ganged plug, said means being readily releasable from or attachable to said plugs so that they may operate independently or in unison, said'means when attached permitting a slight movement of a plug relative to its neighbor to compensate for dimculties in plugging in, due to friction.

12. In a panelboard, of the class described, a plurality of bus bars, a plurality of cup shaped, plug receiving receptacles thereon, all having substantially the samewidth and lengths equal to non-fractional multiples of a predetermined common factor length, and all having identical mounting details, whereby they may be interchangeably mounted on said bars, certain of said receptacles being constructed to receive one wide plug, and certain being constructed to receive a plurality of narrower plugs, said plugs and said receptacles each comprising a body of insulating material upon which are disposed mutually cooperating contacts, the latter being inaccessible when the plugs and receptacles are in cooperative changeably mounted on said bas, certain of said receptacles being constructed'to receive one wide plug, and certainbeing constructed to receive a plurality of narrower plugs, said plugs and said receptacles each comprising a.l body of insulating material upon which are disposed mutually cooperating contacts, the latter being inaccessible when the plugs and receptacles are in cooperavlili functioning members, means accessible from the tive relation, the plugs carrying fuses which are enclosed within the receptacles when the plugs are plugged in.

14. A sectionalized panelboard of the dead front convertible type including a plurality of fixed bus bars, a plurality of `units having bases iixedly mounted with respect to said bars and connected to one or more of them by selective connectors, each unit being provided with circuit protective velements and with a head carrying means to connect said elements, said heads being movably mounted with respect to said bases so as to be movable to and from circuit connection posiinterchange of heads, as well as adjustment of fuse receiving means in the units, is permissible without disturbing the ordered appearance oi the panelboard, each unit being provided with removable means to prevent the receiving thereby of any but a fuse for which it is intended.

l5. .a sectionalized panelboard employing a plurality oi' adjacent units which are relatively interchangeable without disturbing the ordered appearance of the panelboard as a whole, each unit being provided with adjustably mounted and replaceable means for receiving and holding a cartridge fuse, so that different sizes and types of fuses on a unit may be interchanged, cach unit including a xed base and a movable head carrying the iuse receiving means, the heads of various units being interchangeable for fuse interchange, each base being provided with removable means for preventing the mounting thereon of any but the head `for which it is intended.

16. A sectionalized panelboard including a plurality of bus bars, a plurality of units, each of which is provided with circuit protective elements including convertible and replaceable cartridge fuse receiving means, and each of which is further provided with relatively movable switchfunctioning members, means accessible from the front of the panelboard for connecting the units to one or more of the bus bars as desired, before or after the panelboard is formed 4as a whole, the means being so interlocked with respect to the switch-functioning members that exposing themeans for connecting them to bus bars is not possible unless and until the switch functioning members have been moved to the position in which they break the circuit through the unit.

17. A sectionalized panelboard including a plurality of bus bars, a plurality of units, each-oi front ci the panelboard for connecting thel units to one or more of the bus bars, as desired for phasing and rephasing, before or after the panelboard is formed as a whole, the means being concealed by the switch functioning members, when they are in a circuit making position, so that exposing the means for a re-phasing is not possible unless and until the switch-functioning members have been moved to the position in which they break the circuit'through the unit, the cartridge fuse receiving means being similarly interlocked with respect to the switch-functioning members.

18. A sectionalized panelboard including a plurality of bus bars, a plurality of units, each of which is provided with circuit protective elements including convertible and replaceable cartridge fuse receiving means, and each of which is further provided with relatively movable switchfunctioning members, means accessible from the front of thepanelboard for connecting the units to one or more of the bus bars, as desired, before or after the panelboard is formed as a whole, the means being so interlocked with respect to the switch-functioning members that exposing the means for connection to bus bars is not possible unless and until the switch-functioning members have been moved to the position in which they break the circuit through the unit, the cartridge fuse receiving means being similarly interloclred with respect to the switch functioning members, the units being interchangeably mounted on the panelboard, the construction as a whole being such that interchange of units, adjustment, interchange or replacement of fuses, and changes of phasing are all impossible of performance while there is a current through the unit considered.

i9. A vsectionalizedpanelboard including a plu- 'units mounted over and connected to said bus bars, means for connecting the units to any one or more of the bus bars, the units having lengths equal to integral multiples of the spaces between said connection means, each of said units having therein adjustable and interchangeable cartridge fuse receiving means and having switch functioning members, the latter being so mounted that access to the live parts of the. units is not possible until and unless the switch functioning members have been moved to their circuit interrupting positions.

20. A sectionalized panelboard including a plurality of bus bars having uniformly spaced connection means, a plurality of circuit protective units, mounted over and connected to said bus bars, means for connecting the units to any one or more of the bus bars, the units having lengths equal to integral multiples of the spaces between` -rality of bus bars having uniformly spaced coni their circuit interrupting positions, all of the units being of the same width, so as to present an ordered appearance when combined to form a panelboard. I

21. A sectionalized panelboard including a plurality of bus bars having uniformly spaced connection means, a plurality of circuit protective units, mounted over and connected' to said bus bars, means foiconnecting the units tc any one or more of the bus bars, the units having lengths equal to integral multiples of the spaces between said connection means, whereby the units may be interchangeably mounted on said bus bars, each of said units having therein adjustable and interchangeable cartridge fuse receiving means and having switch functioning members, the latter being so mounted that access to the live parts of the units is not `possible unless and until the switch functioning members have been moved to their circuit interrupting positions, the switch functioning members indicating at a. glance. by their position, the condition of the circuit through them and the unit being considered, the connecting means for the units including parts to'which access for connection purposes, can be had from the front of the panelboard, the parts being interlocke'd with the switch members, so that access thereto for connection can be had only when the circuit is interrupted. y

22. A sectionalized panelboard including a plurality of bus bars having uniformly spaced connection means, a plurality of circuit protective units, mounted over and connected to said bus bars, means for connecting the units to any one or more of the bus bars, the units having lengths equal to integral multiples oi the spaces between said connection means, whereby the units may be interchangeably mounted on said bus bars, said units having therein adjustable and interchangeable cartridge fuse receiving means and having switch functioning members, the latter being so mounted that access to the live parts of the units is not possible until and unless the switch .functioning members'have 'been moved to their circuit interrupting positions, the switch functioning members indicating at a glance, by their position, the condition of the circuit through them and the unit being considered, the switch functioning members including 'relatively movable switch parts having fuse receiving means and one of which covers the other part to enclose the fuse within the interior of the unit.

23. A relatively large area sectional panelboard including a plurality of xdly mounted busbars having uniformly spaced connection means, a

means is prevented unless and until the current through said unit has been interrupted, each of the units also having therein means for receivlengths equai to integral multiples of the spaces between said connection means, phasing means selectively and interchangeably connecting said units to onelor more oi said busibars, said units being also provided with adjustable fusing means for holding and connecting any one of a number of different sizes and types of cartridge fuses, conti-oi means for the units, the construction as a whole being such that the phase and fuse characteristics of each circuit may be varied by interchange of the units and/or of the controlv means thereof, therein, the said phasing and fusing means being interlocked with respect to the control means in each of the units so that any changes in the phase and fuse characteristics of a unit cannot be made until the current through the unit has been interrupted.

25. A relatively large area sectional panelboard comprising a board having a plurality of fixedly mounted bus bars having uniformly spaced connection formations, a large number of relatively small area, closely adjacent, interchangeable circuit protective fused, current lead-oir units connected to said bus bars by connecting n@ means cooperating with said connection formations, said units having diierent lengths, equal to integral `multiples of h; spaces between said connection formations, t e'units being provided with relatively movable, switch-functioning members; interchange of the unitsbeing possible without disturbing the ordered appearance of the panelboard as a whole, access to the means for connecting the units to the bus bars being impossible unless and until the switch functioning members have been moved to the position in which they break `the circuit through the unit being considered.

HARRISON J. L. FRANK.'

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