US3166372A

US3166372A - Method and apparatus for connector orientation

Info

Publication number: US3166372A
Application number: US141841A
Authority: US
Inventors: Just Alex
Original assignee: Malco Manufacturing Co Inc
Current assignee: Malco Manufacturing Co Inc
Priority date: 1961-09-29
Filing date: 1961-09-29
Publication date: 1965-01-19
Anticipated expiration: 1982-01-19

Description

Jan. 19, 1965 A. JusT 3,166,372 7 METHOD AND APPARATUS FOR CONNECTOR ORIENTATION Filed Sept. 29, 1961 3 Sheets-Sheet l /Z I II 1! 9.1. A 3,!

; 8 gum F /Z m /35 2% K c 300000 ofi lgzfifi fi g 0E @0000; C 30000000 lc 0@,@.@@0= 0c 3000000 0|c c l 0c 000000000 0[ 300000000 0c 300000000 olc 300000000 25 INVENTOR. //e,r g/z szj Jan. 19, 1965 A. JUST 3,166,372

METHOD AND APPARATUS FOR CONNECTOR ORIENTATION Filed Sept. 29, 1961 s Sheets-Sheet s IHI 3,156,372 Patented Jan. 19, 1965 United States Patent Office 3,166,372 METHOD AND APPTUS FUR CQNNECTGR OREENTATIGN Alex Just, River Forest, 12L, assignor, by mesne assignmenw, to Maico Manufacturing Company, Inc, Chicago, 111., a corporation of lllinois Filed Sept. 29, 1961, Ser. No. 141,841 (.laims. (Ci. 33Q186) This invention relates in general to electrical connectors. It deals more particularly with apparatus and a method for polarizing or indexing blocks of terminal connectors with respect to mating connectors in a terminal board.

In missile control panels or electronic computers, for example, it has become the practice, due to recent development in the field, for huge terminal boards or banks of smaller boards to provide the base for thousands and thousands of terminal connections in corresponding circuits. these connections. Ordinarily female type terminalsjare set in groups in the board and separate unitary blocks of male terminals must mate with specific groups of the former to establish correct and proper circuit connections. Herein lies a problem and danger. Twenty to a hundred or more terminals might be congregated in one group or block, a hundred or more groups or blocks in one board. Yet, the correct connection of each block to a proper group in the board must be made quickly and errorlessly time after time as circuits are completed and broken in a missile firing submarine, for example. Heretofore, correctly mating corresponding groups and blocks of connectors has been a time consuming and tedious task.

An object of this invention is to provide a connector assembly which insures proper connection of a block of terminal connectors with a block of mating terminal connectors. 1

Another object is to provide a connector assembly which prevents connection of a block of terminal connectors with the wrong block of mating terminal connectors in a bank of blocks of mating terminal connectors.

Yet another object is to provide .a connector assembly including apparatus for mechanically protecting the terminal connectors from damage when the terminal blocks are disconnected.

Another object is to provide a connector assembly including apparatus for protecting the terminal connectors from electrical contactor short circuit when the terminal blocks are disconnected.

Another object is to provide a connector assembly Groups or blocks of terminal connectors form blocks of mating terminal connectors set in a terminal board. While specifically arranged male and female connectors are hereinafter referred to, it will be understood that many other types or arrangements of mating connectors may be used in accordance with the teachings of the invention.

Briefly, the invention contemplates characteristically indexing each set or block of male connectors with the corresponding female terminal connectors in the terminal board. One embodiment of the invention envisages the use of separate and individual indices surrounding each block of female terminal connectors and set in the terminal board. This construction facilitates seating and removing individual indices and readily adapts itself to on-the-job programming.

Another embodiment of the invention contemplates the use of unitary indexing apparatus including separate indices forming a part of the unitary. apparatus and pro truding therefrom. In this embodiment the indexing structure is associated as an element with each block of connectors, regardless of the indexing structure utilized,

with complementary blocks of female terminal connectors, is substantially uniform. It provides electrical and mechanical protection for the male terminal blades when which electrically shields the terminal connections from A further object is to provide a connector assembly v facilitating on-the-job programming of any indexing variation desired.

Still another object is to provide a method for insuring proper connection of a block of terminal connectors with a block of mating terminal connectors.

' A further object is to provide a method for insuring correct placement and proper connection of a block of terminal connectors in a bank of blocks of mating terminal connectors.

The above and other objects are realized in accordance with the present invention by providing a methodand apparatus, including several embodiments, for quickly and accurately positioning and properly connecting blocks of terminal connectors in pre-selected. position in a bank of corresponding blocks of male and female terminal connectors are unconnected and additionally provides electrical shielding for the electrical connection itself.

The invention, both as to its organization and method of operation, taken with further objects and advantages thereof, will be best understood by reference to the following description taken in connection with the accompanying drawings, wherein the several embodiments are illustrated:

FIGURE 1 is a perspective view of a portion of a terminal board showing blocks of male and female terminal connectors and associated indexing structure forming one embodiment of the invention, certain details of the boards 7 construction having been omitted for purposes of clarity;

FIGURE 2 is a plan view of a portion of the terminal board illustrated in FIGURE 1 showing blocks of male and female terminal connectors and associated indexing structure; 7

FIGURE 3 is a view taken alongline 33 of FIGURE 2 showing mating blocks of male and female terminal connectors and associated indexing structure;

FIGURE 4 is an exploded end view of the blocks of unmated terminal connectors and associated indexing structure illustrated in FIGURE 3;

FIGURE 5 is a sectional view through a portion of a terminal board showing a printed circuit board and associated indexing structure;

FIGURE 6 is a view taken along line 6-6 of FIG- URE 5;

FIGURE 7. is a perspective view of a portion of a terminal board showing a block of female terminal con- UREJ;

, circuits.

FIGURE 9 is a perspective'view of a portion of a I terminal board showing a block of female terminal condetermined distance above the topsof the bushings 2%.

I This extends the index bushings into a position of prominectors and associated indexing structure forming the basis for 'yet another embodiment of the invention, and

FIGURE 10 is a view t aken along line 1;tl1 of FIG- URE9.

nence and insures their being recognized by a descend- 'ing male terminal connector block 14 before any elec- Referring to the drawings, a first embodiment of this num sheet stock and has'a plurality of holes 11 extending through it at generally regularly spaccd intervals. Although an aluminum board is described, its use is merely a matter of choice and a wide variety of materials might be advantageously utilized.

Only a few of the holes 11 are shown in FEGURE 1, the remainder having been omitted in the interest of clarity. The board would normally be apertured across its entire surface or in the alternativelarge banks of holes might be separated by unapertur'ed sections of the board. Blocks lZj'of female terminal connectors 13 are-mounted in groups of adjoining holes in predetermined relationship on the board. In practice, each block 1.2 of female terminal connectors 13 is adapted to. receive a specific block 14 of male terminal connectors. For example, each set of

mating terminal blocks

12 and 14 might be a terminal connection between elements of an electrical circuit or combination of circuits. It will be easily seen that. inadvertent connection of a block of male terminal connectors forming a composite terminal for one circuit or combination of circuits with the wrong block of female terminal connectors might wreck havoc with complicated electrical equipment. linewith this, misalignment and consequently ofifset con nection'of what actually are mating blocks of terminal connectors is also highly undesirable and would be disastrous'to the function of a circuit or combination of This invention insures the mating of correct blocks of terminal connectors and in' conjunction with this prevents misconnection between 'blocksforming a normally mated pair of male and fem'aleter-rninal connector blocks. v 1 I 1 i.

Returning to the embodiment of thisinventio'nillustrated in FIGURES l6,'and specifically to FIGURES 2 and 4, each female terminal connector 13 in a block includes a' sleeve or bushing 2t} s'eate'din a hole 11in the terminal board 10. A female terminal pin 21 ex! tends through each bushing 12% and has a wire wrap shank 22 at one end thereof. As disclosed in. U.S. Patent No. 2,995,617, entitled Self-Locking Terminal, August 8, 1 961, in which I am the co-inventor, a selfloc king or expansionfit is formed between the bushings 2b and the holes 11 through the cooperation of the locking shanks (not shown) forming part of the ter- 'rninal pins Zlwithideach bushing 2t A male blade receiving fork'forms the other end of each terminal pin 21 within the bushings 2h. it will alsobe seen that the bushings 2d are generally square orrectangular inccrosssection, establishing an orientating fit'between the bushings themselves. The specific construction of the terminal connectors including the self-locking fit between the terminal board it and the-connectors 13 forms no I part of this invention, however, and a detaileddescription thereof is n ot thought to be necessary; As best seen in FIGURES 1 and 2, a total'of three index bushings 25 are seated in the rows R of holes immediately bracketing each block 12. of female terminal connectors 13. in the terminalboard 1th The index bushings 25 are 'solidfno bore being provided in them since they {are notadapted to receive terminal pins 21 in themanner of the terminal connector bushings 29;

Referring now to FIGURES 3 and 4,'it will be seen that index bushings 25 are larger than the adjoining terminal connector bushings 20. Consequently, they extend apreissued I 1 and. one on the other side.

" board is established. Since a total of ten holes is available, as seen in FIGURE 2., in each row R of holes bracketing a block 12 of female terminal connectors 13, it will be obvious thatalarge number of variations in the relative positioning of each group or" three index bushings 25 is available. t is not intended, however, that the use of ten holes be restrictive. More or less would be available, depending upon the size of the block 12 of female, terminal connectors l3.

Two bushings are shown on one side or" each block 12. This combination has been found most suitable for large terminal boards in which a great number of blocks of female terminal, connectors are mounted for'connection to corresponding blocks of male terminal connectors to complete various circuits. It

'will' readily be seen that the use of three index bushings in the manner described above eliminates the possibility of connecting a block of male terminal connectors in inverted relation to the Wrong block of female terminal connectors, as might be the case if only two bushings were used, for example. However, under certain conditions 'it' is contemplated that moreor less than the three index bushings describedmight be satisfactory. in addi tion, though the indexing structure illustrated herein includes index bushings 25, it is conceivable that various types of pins might be utilized with identical results. For

V example metal dowels might be used.

Although the indexing structure associated with the blocks 14 of maleterminal connectors 15 remain the sarne, regardless of whichever mating indexing structure associated with the female terminalconnecto rs is used, the actual construction of diiferent blocks of inale terminals might vary depending upon the use contemplated. One construction of primary importance is the wire wrap block seen in FIGURES 1-4. Such afbloclr might intending skirts 31 and form the legs of the plate while. a-base 34 connects the legs. The base of each U-shaped plate 31) has a generally rectangular cut-out 35 therein.

' such as screws 3'7 and nuts A terminal plate 36 is seated between thelegs 31 and 50f the Ll-shaped plate '36 and secured to the base 34 at nal block might include bushings ll seated in corresponding holes (not shown) in the terminalplate This is best illustratedin FIGURE .4 where four rows of bushmgs 41 having generally rectangular heads are nested in intimate relationship. Terminal pins 42 extend through the bushings t l and, might establish a self-locking fit between the bushings and corresponding holes (not shown) mentioned patent.

in the plate 36 in the manner disclosed inthe afore- The details of the ,fit between. the terminal pins.42,.the bushings 41' and the terminal. plate 36 form'nojpart of thi invention, however, anda com plete description is not thought to be necessary.

Each terminal pin includes a ,Wire wrap shank 43 V normally extending upwardly from the plate 36 and male blades 44 which protrude downwardly from the bushings 41 within the confines of the

skirts

31 and 32 of the U-shaped plate 30. As is best illustrated in FIGURE 4, also, the

skirts

31 and 32 extend below the ends of the male blades 44. Consequently, regardless of how the block 14 of male terminal connectors 15 is handled, the male blades 44 cannot come into contact with any substantially flat surface. This is important in that the positioning and spacing of the blades 44 is a matter of some criticality and any blows suffered by the blades can easily throw them out of alignment and consequently pre vent their seating in the proper female terminal connectors 13 in a corresponding block 12 thereof. In line with this, the downward-

1y extending skirts

31 and 32 prevent short circuiting of the blades 44 due to inadvertent contact of the blades with conducting surfaces when mating blocks of male and female terminal connectors are disconnected. The skirt are additionally important in that they provide electrical shielding for the connections established by the various mating pairs of male and femaleterminal connector blocks 14 and 12, respectively. Consequently, electrical interference between adjoining circuits is substantially reduwd.

FIGURE 3 best illustrates the notche 50 cut in the

skirts

31 and 32 of the U-sh-aped plates 30 and forming complementary indexing structure or indicia receiving means. The notches 50 might be cut in the

skirts

31 and 32 during manufacture with a punch and die, for eX- ample. On the other hand, a portable hand cutting tool might as easily be utilized. The notches 50 are cut in such positions in the

kirts

31 and 32 that they align with and are adapted to receive the characteristically placed index bushings 25 surrounding the block 12 of female terminal connectors upon which the block of male terminal connectors in question is intended to be seated. FIGURE 2 illustrates different positioning or programming of the index bushings 25 around various block 12 of female terminal connectors 13 and it will be readily understood that the notches 50 in the

skirts

31 and 32 would be cut to align with these index bushings.

The apparatus comprising the indexing or polarization assemblies and forming the basis for thi embodiment of the invention is of such nature that index bushings 25 can be characteristically placed or replaced in a terminal board while the board is in installed relationship in a computer control panel, for example. In keeping with this, the

skirts

31 and 32 are readily cut and programmed with a portable hand tool for complementary seating over appropriately placed index bushing 25 surrounding the correct block 12 of female terminal connectors 13. This in effect provides on-the-job programming capabilities and facilitates the change or modification of connections in various circuits with speed and dispatch.

Although the male terminal connector block 14 has i been described above as a block of wire wrap terminal connectors 15, a male terminal connector block embodying the features of this invention might take other forms. For example, this invention might be embodied in a printed circuit assembly, as illustrated in FIGURES '5 and 6. In such case, the terminal block might include a printed circuit board 66 carrying a conventional printed circuit (not shown). The printed circuit board 60 is preferably mounted on a shell 61 which in turn carries a terminal board 62 secured to its base in any Well known manner. A male terminal connector arrangement, seen generally at 64, is appropriately mounted in the terminal board 62. In general, the arrangement 64 is connected to appropriate circuits in the printed circuit boards 66 and adapted to be connected to the female termina 3 13 of the female connector block 12.

More specifically, the male terminal connector arrangement 64 includes two or more rows of terminal connectors 76. Each terminal connector 76 comprises a bushing '71 seated in an appropriately formed aperture in the terminal board 62, an upwardly extending angulated shank 72 connected by soldering, for example, to .the aforementioned appropriate circuits in the printed circuit board 66, and a depending male blade 65. A self-locking fit might be established between the terminal connectors 79 and the terminal board 62 in the manner disclosed in the aforementioned patent. In any event, the specific details of construction of the printed circuit assembly described immediately above form no part of this invention. Consequently they have been described in broad terms only. Bracketing the male blades 65 so as to partially enclose them is an inverted U-shaped member 75, seen best in FIGURE 6. The U-shaped member 75 might be secured to the terminal board 62 by appropriately placed bolts and lock nuts of small dimension (not shown). This type of mounting is merely exemplary of various methods which might be utilized for securing the member 75 to the terminal board 62, however.

The U-shaped member 75 might be formed of aluminum, for example, although it might on the other hand he formed of other metals or even non-metallic materials. It includes depending skirts 76 which are adapted to extend below the lowermost portion of the male blades 65, in the manner described hereinbefore in detail in relation to the wire wrap male terminal connector blocks 14. As with the aforedescribed wire wrap terminal connector blocks 14, electrical and mechanical protection of the male blades 65 is afforded by the depending skirts.

The depending skirts 76 of the inverted U-shaped member 75 are notched as at 86, best seen in FIGURE 5. These notches 80 provide complementary indexing structure or indicia receiving means for the index bushings 25 seated in the terminal board 10 in bracketing relationship with a female terminal connector block 12 seated in the terminal board 10. As has previously been pointed out in detail, these bushings 25 are seated in holes in the terminal board 10 forming the, two rows R immediately adjacent the terminal block 12. Preferably there are two such bushings 25 on one side of each block 12 of female terminals 12 and one bushing 25 on the opposite side. This arrangement provides innumerable indexing combinations as has also been clearly ponited out in the foregoing discussion of the indexing structure embodying the features of this invention. In seated relationship, as seen in FIGURE 6, the depending skirts 76 electrically shield each block of terminal connectors and, as has previously been made clear, this guards against electrical disturbances from neighboring mated connector blocks in the terminal board.

A second embodiment of the invention is illustrated in FIGURES 7 and 8, where a terminal board is indicated generally at 11(l. In this embodiment, the indexing structure associated with the female terminal connector blocks forms an integral part of certain of the connectors themselves. The complementary indexing structure associated with each male terminal connector block might be identical to that described in relation to the first embodiment of this invention, however. In elfect, the latter structure is uniformly adaptable to incorporation in indexing assemblies forming the basis for all embodiments of the inven tion. a i

. Referring specifically to FIGURE 7, a plurality of generally regularly spaced holes 111 extend through the ter, minal board 11%. Again, only a few of the holes are shown, the remainder having been omitted in the interest of clarity. In predetermined relationship on the board, blocks 112 of female terminal connectors 113 are mounted in groups of adjoining holes 111. Each female terminal connector 113 includes a bushing 129 seated in a hole 111 in'the terminal board 110. A female terminal pin 121 extendsthrough each bushing and has a wire Wrap shank 122 at one end thereof. As disclosed in the aforementioned patent, a self-locking or expansion fit is formed between the bushings '120 and the holes 111 through the cooperation of the locking shanks (not shown) forming a part of each terminal pin 121 within each bushing 12%.

A male blade receiving fork forms "the otheiendo'f each terminal pin 121 within each bushing 12th The specific construction of the female terminal connectors H5, including the self-locking fit, forms no part ofthis invention, however, and a detailed'description thereof is not thought to be necessary.

As seen in both FIGURE 7 and FlGURE 8, certain or" the bushings 11.259, which might be identified generally as 12th:, have integrally molded index cars 1125 extending .from their sides. These bushings; lZtla are identical in all other respects to bushings 12% and are machine set in a terminal board along with the bushings 12b to pro ide indexing structure complementary with the notched skirts of a mating block 14 of male terminal connectors 15. This embodiment has the advantage of utilizing a minimum amount of terminal board space, since the molded indexing ears 125 need extend only a short distance outwardly from the block 112 of bushings 12% and 12%.

A third embodiment of the invention is illustrated in FIGURES 9 and 10, where a terminal board is indicated generally at 21h. In this embodiment, the indexing structure associated with each female terminal connector block is unitary in form. As in each of the aforedescribed embodiments, however, the indexing structure associated with each male terminal connector block remains unchanged. As has been previously pointed out, in sheet 'the same male terminal connector block construction is adaptable for use with this or any embodiment of the in vention. 7 Referring specifically to FIGURE 9, a plurality of gen erally regularly spaced holes 211 extend through the terminal board Zlll. As in the foregoing description of the first two embodiments of this invention, only a fewof the holes are shown, the remainder having been omitted in the interest of clarity. In predetermined relationship entire board, blocks 212 of female terminal connectors 21 .3 are mounted in groups of adjoining holes 211. Each female terminal connector 213 includes a bushing 22%) seated in a hole 211 in the terminal board 210. A female terminal pin 221 extends through each bushing 22d and has a wire 7 one setting up Connections in a large terminal board.

wrap shank 222 at one end thereof. A male blade receiving fork and locking shank might be formed on the other end of female terminal pin 221 Within the bushing 223, in the manner elicited in the description of the foregoing embodiments of this invention. In such case, a locking fit might be' formed between the bushings 22%} and the holes 211 by theaction of the locking shanks (not shown) of the terminal pins 221. 1

As seen in both FIGURE 9 and FIGURE 10, an indexing plate 225isseated on top of'each'block 212 of female terminal connectors 213. Each plate 225 has a plurality of indexing tabs 225a extending outwardly therefrom in preselected locations. As seen in FIGURE 10, the plate 2245 might be held securely to the top of each block 212 of female terminal connectors 213 by bayonets 2% extending into interstices 227 formed between the. adjoining corners of bushings 222%. Slots 228 in thesurface of the plates 225 align with the jaws of male blade receiving forks (not shown) within the bushings 22b to insurecorrect alignment of male blades with the jaws.

- The indexing plates 225 provide indexing structure complementary with the notched skirts of matingbloclrs lid of male terminal connectors 15. In this respect, of course, the indexing structure is identical to that of the adore-described embodiments of this invention. The tabs 225a of the indexing plate 225 can readily be cut by hand tool to facilitate on-the-job programming.

the corresponding female terminals to male terminal in each embodiment ot this invention described above, electrical and mechanical protection of the male terminal blades is afiorded by the depending skirts in which notches, for example, are cut. In addition, as has been pointed out, electricalshieldingof each connection in the terminal board is provided by the depending skirts.

The polarizationor indexing assemblies embodying this invention provide an efiicient'means of insuring correct location and proper connection ofia block of male terminal connectors in a bank of blocks of female terminal connectors. innumerable combinations of the complementary indexing structures are readily available to any- It has been shown'that the number or combinations in positioning of the indexing structure around the blocks of male and female terminalconnectors is virtually countless. There is no need of having preformed indicia receiving means or notches in the depending skirts of the connector blocks since they can readily be notched onthe-job to coincide with the characteristic positioning of index bushin s 25, cars 125, or tabs 225a. The adaptability of the system is such that its desirability is obvious.

in conjunction with providing a portion of the actual indexing structure, the

skirts

31 and 32 or 75, forexample, protect the blades or" the male terminal connectors from shorting their associated circuits or being knocked out of alignment by blows which might befall them during everyday handling. The shielding provided by the skirts isolates each connection electrically from those about it and consequently tends to eliminate electrical interference between the various circuits having connections in a large terminal board.

Although three embodiments of the invention have been described herein, it is understood that others might fall within its purview and that various modifications and improvements might be made therein. It is intended to cover in the appended claims all such embodiments, modifications and improvements as fall within the true spirit and scope of the invention. a a

What is desired to be claimedand secured by Letters Patent of the United States is: a

1. In a polarization assembly for terminal blocks on a terminal board, the combination of aterminal board having a plurality of spaced holes extending therethrough, bushings seated in a group of said holes, female terminal pins mounted in said bushings, a terminal block for mounting on said terminal board, said terminal block including a plurality of male terminal connectors for connecting with corresponding female terminalpins in said group, said block further including a skirt shielding said male terminal connectors, a' plurality of extra bushings seated in pre-selectedholes adjacent said group of holes,

' said skirt being characteristically notched to coincide with the placement of said extra bushings and forming com- In addition, the slots 223 in each indexing plate 225 limit access to shown) within each bushing-22d. This embodiment also has the advantage of requiring a minimum amount of terminal board space, since the indexing't'abs 225a need ex tend only a short distance outwardly from the blocks 2"12 of bushings 22h.

plementary index means for mating with said extra bushings to insure proper placement andconnection of said block on said board.

2. In a polarization'assembly for terminal blocks on a terminal board, the combination of a-terminal board having a plurality of spaced holes extending therethrough, bushings seated in a group of said holes, female terminal pins mounted in said bushings, a terminal block for mounting on said terminalboard, said terminal'block including a plurality of male terminalconnectors for connecting with corresponding female terminal pins/in said group, said blockfurther including a skirt shielding said male terminal connectors, a plurality of said bushings having ears forming a part thereof and extending outwardly ofsaid group or" bushings, said skirt being characteristically notched to coincide with the placement or" said ears and forming complementary indexrneans'on said -lock formatting with said ears to insureproper placement and connection of said block on said board.

3. In a polarization assembly for terminal blockson a ing a plurality of spaced holes extending therethrough, bushings seated in a group of said holes, female terminal pins mounted in said bushings, a terminal block for mounting on said terminal board, said terminal block including a plurality of male terminal connectors connecting with corresponding female terminal pins in said group, said block further including a skirt shielding said male terminal connectors, an indexing plate seated on said bushings and having a plurality of indexing tabs extending outwardly from said group of said bushings, said skirt being characteristically notched to coincide with the placement of said tabs and forming complementary index means on said block for mating with said tabs to insure proper placement and connection of said block on said board.

4. The assembly of claim 3 further characterized in that said indexing plate has a plurality of slots in its surface, said slots limiting access to corresponding terminal pins.

5. In a polarization assembly for terminal blocks on a terminal board, the combination of a terminal board having a plurality of generally regularly spaced holes extending therethrough, female terminal connectors including bushings mounted in predetermined groups of said holes, a plurality of terminal blocks for mounting on said terminal board, each of said terminal blocks including a plurality of male terminal connectors for completing a connection With. a corresponding group of female terminal connectors, a plurality of index means mounted on said board immediately adjacent to each or" said groups of female terminal connectors, each of said blocks of male terminal connectors including a depending skirt, each of said skirts being characteristically and distinguishably notched to coincide with the arrangement of the index means adjacent a ditterent group of female terminal connectors such that each block of male terminal connectors is adapted to properly mate with a predetermined group of female terminal connectors and prevented from mating with other than said predetermined group of female terminal connectors to insure the proper placement and connection of said blocks on said board.

6. The assembly of claim 5 further characterized in that said plurality of index means includes at least two indicies on one side of each of said groups of female terminal connectors and at least one'indicia on the other side of each of said groups of female terminal connectors.

7. In a polarization assembly for terminal blocks on a terminal board, the combination of a terminal board having a plurality of spaced holes extending therethrough, bushings seated in a group of said holes, female terminal pins mounted in said bushings, a terminal block for mounting on said terminal board, said terminal block including a plurality of male terminal connectors for connecting with corresponding female terminal pins in said group, said block further including a skirt shielding said male terminal connectors, a plurality of members seated in preselected holes adjacent said group of holes, said skirt being characteristically notched to coincide with the placement of said members and forming complementary index means for mating with said members to assure proper placement and connection of said block on said board.

8. In a polarization assembly for terminal blocks on a terminal board, the combination of a terminal board having a plurality of spaced holes extending therethrough, bushings seated in a group of said holes, terminal pins mounted in said bushings, a terminal block for mounting on said terminal board, said terminal block including a plurality of terminal connectors for connecting with corresponding terminal pins in said group, said block further including a skirt shielding said terminal connectors, a plurality of members seated in preselected holes adjacent said group of holes, said skirt being characteristically notched to coincide with the placement of said members and forming complementary index means for mating with said members to assure proper placement and connection of said block on said board.

9. In a polarization assembly for terminal blocks on a terminal board, the combination of a terminal board having a plurality of spaced holes extending therethrough, bushings seated in a group of said holes, terminal pins mounted in said bushings, a terminal block for mounting on said terminal board, said terminal block including a plurality of terminal connectors for connecting with corresponding terminal pins in said group, said block further including a skirt depending on opposite sides of said terminal connectors, a plurality of members seated in preselected holes adjacent said group of holes, said skirt being characteristically notched to coincide with the placement of said members and forming complementary index means for mating with said members to assure proper placement and connection of said block on said board.

10. In a polarization assembly for terminal blocks on a terminal board, the combination of a terminal board having a plurality of spaced holes extending therethrough, terminal connectors including bushings mounted in a group of said holes, a terminal block for mounting on said terminal board, said block including a plurality of terminal connectors for connecting with corresponding terminal connectors in said terminal group, a plurality of members seated in preselected holes adjacent said group of holes, means on said block being characteristically notched to coincide with the placement of said members, said notches forming complementary index means for mating with said members to assure proper placement and connection of said block on said board.

References Cited in the file of this patent UNITED STATES PATENTS 2,750,572 Fox June 12, 1956 2,798,930 Frost July 9, 1957 2,847,543 Cobb Aug. 12, 1958 2,939,100 Watts May 31, 1960 2,952,810 Helton Sept. 13, 1960 2,952,828 Dorizzi Sept. 13, 1960 2,987,693 Wamsley June 6, 1961 3,042,894 Fox July 3, 1962 3,054,078 Baschkin Sept. 11, 1962 FOREIGN PATENTS 1,097,940 France Feb. 23, 1955 616,550 Germany July 31, 1935 630,333 Great Britain Oct. 11, 1949