US2593182A - Monoblock connector - Google Patents

Description

April 15 195 2 E. c. QuAcKENBusl-l 2,593,182

MONOBLOCK CONNECTOR Filed April 22. 1948 V 3J, M

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Patented Apr. 15, 1952 MONGBLOCK CONNECTOR Edward C. Qu-ackenbush, Aurora, Ill., assignor to American Phenolic Corporation, Chicago, Ill., a corporation of Illinois Application April 22, 194s, serial No. 22,631

1 Claim. (Cl. 173-328) The present invention relates to electrical connectors and deals primarily with the provision of connector contacts of novel form, in combination with an improved mounting for the individual contacts whereby the effectiveness of the insulation between the several contacts of a connector is improved, and the liability of formation of electrical creepage paths between the separate contacts carried ina connector mounting block is largely eliminated.

The problem of maintaining effective insulation between a multiplicity of electrical contacts in. a multiple connector is a difficult one', since the contacts must of necessity be quite closely grouped, and since the connectors not only are subjected to considerable physical abuse, but are also exposed to all extremes of climatic conditions.

It is requisite, of course, that to be acceptable to the trade a connector must be satisfactory from a mechanical as well as an electrical viewpoint, and it follows that the several contacts must be held in quite exact position, yet must have a certain freedom of movement, so that they may align themselves with their coacting contacts in the mating connector and tinto each other freely and without binding. In view of this, it has been almost universal prior practice to provide the individual metallic contacts with an enlarged mounting portion adapted to be loosely clamped between oppositely disposed abutment shoulders in each of two separate halves of an insulating mounting block. .This expedient has been very satisfactory from a mechanical'standpoint, but it involves serious electrical shortcomings; primarily due to the fact that repeated cycling of the connector into and out of zones of high and low temperatures, variable humidity, or both, often brings about sufficient condensation of moisture in the joint between the surfaces of the two pieces of the block to establish electric current creepage paths between the individual contacts. These paths are undesirable in any circuits, but are particularly troublesome in communication lines, where even 4a very minute leakage may cause serious operatan opportunity to evaporate. The most serious difficulty appears to arise between permanently joined surfaces intermediate the opposite ends of the metallic contacts, where the length of the path between the contacts is very small.

Considerable research has been directed toward reaching a solution to this problem, and some progress has been made, as by devices designed to effect a moisture-proof seal around the critical areas, but despite the large sums of money expended to overcome it, the problem still persists; and no simple, practical and entirely successful solution has heretofore been forthcoming. It is accordingly the primary object of the present invention to provide, in an electrical con-- nector, a combination of a novel form of individual metallic contacts and a mountingblock of insulating material so. arranged and constructed that the contacts are carried loosely, yet

in exact position, and wherein there are no intercontact surfaces through the insulating block at any point between the opposite faces of the block, so that the establishment of creepage paths between the individual contacts is unlikely.,

A further object of the invention resides in the provision of an electrical connector wherein the insulating block in which the connector'contacts are mounted is a single, unitary, one-piece structure, with the contact cavities extending entirely through it but separated by a so1id, unbroken wall of insulation throughout'their length. Thus, the formation of creepage paths in the block itself is eliminated. l

A still further object is to provide a contact mounting block as indicated above, with the mounting portion of each contact substantially shorter than the length of the cavity, and terminatingV a considerable distancefrom the, back face of the block. This'expedient provides a particularly long contact-to-contact distance across the back face of the block, and largely avoids the risk of electrical leakage at the rear face of the block.

.'Ihe'manner in which these objects are accomplished will be apparent by reference to the following description and to the drawings of this disclosure, wherein:

Figure 1 is a side elevational view, partly in section, showing an electrical connector constructed in accordance with the teachingsl of this invention;

Figure 2 is an enlarged sectional View of the unitary mounting block, connector contact and spacing sleeve with which the present invention is specifically concerned; and

Figure 3 is a perspective view of one of the insulating spacing sleeves.

The preferred embodiment of the invention is illustrated in connection with a train line receptacle and connector including a fixed socket tting and plug having mating male and female contacts. The fixed socket has a housing comprising a metallic casting I adapted to be mounted on a xed supporting surface and sealed thereto by a gasket I I. A pivot arm I2 and cover I3 are hinged to the socket to close the outer end of the casting I0 when the connector is disengaged, and a gasket is positioned on the cover to establish a seal over the contacts.

The xed socket of the -connector carries a number of pin contacts I5, each of which is joined to a iiexible conductor I6. Thevindividualcontacts I5 include enlarged mounting shoulders I'I, received in one of the cavities of a mounting block I8, and held in position by spacing sleeves A resilient rubber sealing member 2 I is positioned 'over the. rear surface of the block I8and is: heldV in. position Vby an insulating sheet 22, secured by-the cap screws 23 in any convenient manner.

:The removable plug of; the connector includes alhousingcomprising a forward-portion 25 and a bodyportionZB having a screw threaded fitting 21 by which the. housing is: joined to a multiple conductor cable 28.- Aninsulating block 3l; of unitaryone-piece construction is mounted in the housing, and is securely7 held in place by an enrlarged; shoulder 32'fitted in a recessin the head vportion-25 of the housing. -fIhe block 3,I has a plurality'of contactY cavities ingwhichgthe female contacts ofl the connector are mounted'. Each of thepavities extends between; the ,front face 33 -and the=rear facef34, ofnthe block,;and includes forward, centerV andV rearportions 0f v*progres- --sivelyf increasing diameter. As shown, the `for- .wardf-openings. through the` frontface. 33 constitute the,A portionof minimum diameter of the Lcavity,`H and. terminate.- in.. a Y rearwardly facing abutment shoulder 36 from which the center, or -mounting portion 3'I,;of thecavityextends to a :second shoulder 38 and to therearportion 33 of `maximum' diameter (Figure 2) The mounting portion of,` the female ,contacts comprises a relatively long tubular portion d! (Figure 2),-, which terminates in, al front stop surfacef 42 and a shoulder,y or rearwardly disposed .stop4 surface 43, and as.v showm; each 0f. the C Ol-f tacts includes a reducedportion. 45; having aninternal bore or cavity in vwhich one, of the exible conductors. 46 ofthe cable 28 isv secured. A cylindrical insulating sleeve .Mabutsagainst' the shoulder. 43 to retain the contact in position in the cavity. The sleeves'1 inzturn, are secured in `place inthe cavitiesby a rubber sealing gasket `etanol' insulating sheetli. The sleeve may be of one-piece construction as shown in vFigure 3, -or maybe 'split to permit it to be put in place after the contact is joined to its iiexibleconductor, butin either caseA it will function in a manner to limit rearward movement of the contacts,` towards the back face ofV the mounting block. The male contacts .are secured inthe ;s ame manner as the female;and although the Amounting portion of the male contacts consists -of the ,fla-nge' I 'I and is, of course, notably shorter than the sleeve portion 4I of the female, yet its front and, rear-surfacesl coact with` the internal Shouldersofzthe cavityr-and withthe sleeves I9 inyan identical; manner.

It is to be noted; that sincethe insulating mounting blocks I8 and 3I are of unitary onepiece construction, there is no parting line extending between the individual contacts at any point between the opposite ends of the block, and it follows that no creepage paths can develop between the contacts unless they extend across the front faces. This is quite unlikely on the exposed face surfaces of, the block, since long experience has shown that no great difficulty isencountered at this point, and that if creepage paths are to develop at all, they are more apt to establish themselves across the interior sealed surfaces of the connector. This is extremely improbable in a connector constructed according to this teach- Ying, since itis obvious that no interior creepage v path can develop unless it is to extend from the shoulder-38. along the full length of the bore 39,

Vbest electrical characteristics, and that a conacross the rear surface 34 of the block, and back the entire length of another bore 39 to the shoulder 38 of the next contact. lThis is an extremely long path,V and its unusual length obviates the diiculties `heretofore encountered in condevelop across this greatly increased distance.

From the foregoing, it will be apparent that Y theteachingsofl the present invention effect a happy reconciliatmn between thevrequired mechanical. characteristics of a connector and the nectar-designed and constructed in accordance with these teachings achieves a degree of elec trical perfectionnot heretofore obtained,V yet in lll` so doingmaintains the-essential mechanical characteristics...,That is, a connector according tothis; disclosure permits slight looseness oi each. ,individual contact, sothat each may align itself with; itsmating Vcontact to engage and disengage freely,4 although: the entire group is nevertheless held inzqllitegaccurate relative position. The

`present disclosurerthus offers, in a simple, rugged Aandpcompact structure, a practical solution to e problem that has long plagued workers in the eld towhich thisY invention is related, but to which no satisfactory solution has heretofore been forthcoming.

The. drawings attachedfhereto illustrate a present commerical embodiment of the inven- -tion in the precise form deemed-preferable for a train line connector, but it is recognized that various deviations from the exact structure disclosed may be indulged in without departing from these teachings, and it is accordingly pointed out that the inventive concept is notlimited to the precise arrangement illustrated, but extends equally toany modified structure coming within the terms of the appended. claim.

Having thus described the invention what I claiinas new and desire to protect by United States Letters Patent is:

In an electrical connector having a metallic housing with an open front end adapted to engage a mating connector, a contact mounting block of dielectric material; said block having side walls secured within the housing, an exposed front face surface adapted to abut the front face surface of asimilar block in the mating-connector and a rearv surface enclosed Within the housing; at least one contact cavity in said block, having a face orice of relatively small diameter at the front surface of the block, with a rearwardly facing shoulder near the forward end of the cavity and an enlarged mounting portion of the cavity extending rearwardly from the shoulder; a metallic contact element having a mounting portion loosely fitted within the enlarged portion of the cavity; the mounting portion of said contact having a forwardly facing stop surface at one end and a rearwardly facing stop surface at its other end and being substantially shorter than the mounting block, with vthe forwardly facing stop surface positioned in en- Y 6 loosely fitted within the cavity and bearing against the rearwardly disposed stop surface to limit rearward movement of the contact, and a sealing sheet including perforations closely surrounding an electrical conductor leading from each contact and bearing against the end of the spacing sleeve to retain the sleeve and contact in position in the cavity.

EDWARD C. QUACKENBUSH.

REFERENCES CITED The following references are of record in the filer of this patent:

UNITED STATES PATENTS Number Name y Date 2,307,972 Strunk Jan. V12, 1943 2,411,861 Antony, Jr., et al. Dec. 3, 1946 2,419,018 Gudie Apr. 15, 1947

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