Source: http://www.google.com/patents/US5066250?dq=7125605
Timestamp: 2014-07-26 05:56:46
Document Index: 324102792

Matched Legal Cases: ['arts 120', 'art 122', 'art. 4', 'arts 24', 'arts 24', 'arts 120', 'art 116', 'art 118']

Patent US5066250 - Polarizing key permitting connector displacement - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign in<nobr>Advanced Patent Search</nobr>PatentsPolarizing keys are provided to allow only selected pairs of connectors to be mated, which allow one connector to be displaced slightly after mating, while also providing a large area of interference between nonmating keys to prevent their connectors from mating. Each key has an elongated keying portion...http://www.google.com/patents/US5066250?utm_source=gb-gplus-sharePatent US5066250 - Polarizing key permitting connector displacementAdvanced Patent SearchPublication numberUS5066250 APublication typeGrantApplication numberUS 07/605,445Publication dateNov 19, 1991Filing dateDec 21, 1990Priority dateDec 21, 1990Fee statusLapsedAlso published asEP0563064A1, WO1992011670A1Publication number07605445, 605445, US 5066250 A, US 5066250A, US-A-5066250, US5066250 A, US5066250AInventorsDavid E. WelshOriginal AssigneeItt CorporationExport CitationBiBTeX, EndNote, RefManPatent Citations (4), Referenced by (9), Classifications (4), Legal Events (5) External Links: USPTO, USPTO Assignment, EspacenetPolarizing key permitting connector displacementUS 5066250 AAbstract Polarizing keys are provided to allow only selected pairs of connectors to be mated, which allow one connector to be displaced slightly after mating, while also providing a large area of interference between nonmating keys to prevent their connectors from mating. Each key has an elongated keying portion with an interfitting side 94 (Fig. 9) which lies opposite the interfitting side of a similar corresponding key when the connectors are mated. Each interfitting side has forward and rearward parts 120, 122, with the rearward part 122 being indented with respect to the forward part.
I claim: 1. In a connector system which includes plug and receptacle connectors with contacts having front ends that mate when the connectors move in a mating direction towards each other, each connector having a key which is polarized by its rotational orientation about a key axis extending in said mating direction, wherein each of said keys lies on one side of said key axis and a pair of mating keys lie on opposite sides of said key axis when said connectors are mated, and wherein the connectors and said mating keys can be shifted perpendicular to said mating direction after said connectors are mated, the improvement wherein:each of said keys has forward and rearward parts that are positioned so the forward part of each key lies opposite the rearward part of the other key when the connectors are fully mated, the forward part of each key lying closer to the key axis than the rearward part of the same key. 2. The improvement described in claim 1 wherein:the forward and rearward parts of each of said keys forms approximately one half of a hexagon, including first and second key surfaces forming adjacent sides of the hexagon and third and fourth surfaces forming less than half of third and fourth sides of the hexagon, and each key forms an interfitting key side connecting said third and fourth key surfaces with the forward part of each key having longer third and fourth surfaces than the rearward part of the key. 3. A connector arrangement comprising:first and second electrical connectors which have contacts that mate when the connectors are moved in forward directions toward each other, said first connector having a first key mounted thereon and said second connector having a second key mounted thereon; each of said keys has a keying portion with an interfitting side which lies opposite the interfitting side of the other key with an imaginary plane between said interfitting sides, when said connectors are mated, and each interfitting side has forward and rearward parts with each rearward part being indented with respect to the forward part, and with each forward part lying closer to said plane than the rearward part. 4. The key described in claim 3 wherein:said keying portion of said first key has a cross-section which is slightly less than half of a hexagon, and includes first and second key surfaces lying on the adjacent sides of the hexagon and third and fourth key surfaces each comprising less than half of third and fourth sides of the hexagon that lie respectively adjacent to said first and second sides, and said interfitting side comprises a line connecting said third and fourth surfaces at cross-sections of said keying portion, with the third and fourth surfaces being longer in a lateral direction that is perpendicular to said forward direction, along said forward part of said interfitting side than along said rearward part of said interfitting side. 5. In an electronic circuit apparatus which includes a rack having a plurality of module-receiving tracks, a multi-contact rack connector at an end of each track, a cold plate beside the track, and a clamping device for clamping a module portion lying in the track against the cold plate, and wherein the apparatus also includes a plurality of modules that each comprises a heat sink plate that can slide along the track, at least one circuit with electronic components mounted on said plate, and a multi-contact module connector mounted on said plate and having contacts coupled to said module components, and wherein said rack connector has a polarizing key that mates with a corresponding polarizing key of only a selected one of said modules, and wherein each polarizing key has an elongated keying position with an interfitting side that extends in said mating direction and each connector has a space adjacent to the interfitting side of its key for receiving the keying portion of the key of the corresponding connector, the improvement wherein:the keying portion of each of said keys has a forward part which is closest to a key of a mating connector before the connectors begin to mate, and has a rear part, with the interfitting side of the rear part of a key being instepped with respect to the front part of that key. 6. The improvement described in claim 5 wherein:said keying portion of said first key has a cross-section which is slightly less than half of a hexagon, and includes first and second surfaces lying on the adjacent sides of the hexagon and third and fourth surfaces each comprising less than half of third and fourth sides of the hexagon that lie respectively adjacent to said first and second sides, and said interfitting side comprises a line connecting said third and fourth surfaces at cross-sections of said keying portion, with the third and fourth surfaces being longer, in a lateral direction which is perpendicular to said mating direction, along said forward part of said interfitting side than along said rearward part thereof. Description
BACKGROUND OF THE INVENTION High quality electronics equipment, such as for military applications, is often designed around modules. Each module consists of a metal heat sink plate, circuit boards laminated to opposite sides of the plate, and a connector at one end of the plate. Several of such modules or panels are installed in a rack by inserting projecting upper and lower portions of the heat sink plate into upper and lower groove-like tracks of the rack and sliding the module into place. As the module is slid into place, the multiple contacts of the module connector mate with corresponding contacts of a rack connector. Finally, clamps are operated to tightly clamp the projecting upper and lower ends of the plate against a side of the track which forms a cold plate that removes heat from the module.
SUMMARY OF THE INVENTION In accordance with one embodiment of the present invention, a key system is provided for polarizing electrical connectors, which provides a considerable gap between keys to enable sideward displacement of one fully mated key with respect to the other, while providing large interference between mismating keys. A first key has an elongated keying portion extending in a mating direction, with an interfitting side which can lie opposite the interfitting side of a mating similar second key. The interfitting side of each key includes forward and rearward parts, wherein the forward part first encounters the mating key as they approach each one another prior to mating. The rearward part of the interfitting side is instepped with respect to the forward part of the interfitting side. As a result, there is a very narrow gap between the forward parts of the interfitting sides as the keys start to mate, to provide a large area of interference between mismated keys. However, once the keys are fully mated, when the rearward part of each interfitting side of a key lies opposite the forward interfitting side of the other key, there is a larger gap between the keys to allow substantial sideward movement of one key with respect to the other.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded partial perspective view of an electronic circuit apparatus which uses polarizing keys of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 illustrates an electronic circuit apparatus 10 which includes a rack 12 having a plurality of module-receiving tracks, including upper and lower tracks 14, 16. A module 20 includes a heat sink plate 22 with upper and lower parts 24, 26 which can slide along the tracks 14, 16 into the rack. The module includes a pair of circuits 30, 32, each having components 34 to be connected to circuitry of the rack, such as a mother board 36. The module has a module plug connector 40 which connects to a rack receptacle connector 42 as the module is inserted in a mating direction 44 deep into the rack. When the module has been fully inserted in the mating direction, clamps 46, 48, such as of the wedge lock type, are operated to shift the upper and lower parts 24, 26 of the module heat sink plate sidewardly, so they press firmly against side walls 50, 52 of the tracks. The side walls may be referred to as cold plates, which are maintained at a low temperature so they cool the module heat sink plate 22 to cool the components of the module.
FIG. 6 is a top or front view of the module key 61P, and shows how there is interference with a mismating key 66N. A properly mating key would be at the position 66P, but the mismating key 66 is rotated 60� about the key axis 74P, so its center point has been rotated from the position 102P to the position 102N. In that case, the top surfaces 110P, 110N of the two keys make contact in the area indicated at 112P. It may be noted that the top or front surface of each key has a chamfer 114P of a width of 0.004 inch or 4 mils (each mil equals 0.001 inch) surrounding the top or front surface 110P of the key. The top surface contact area 112P is relatively small. Commonly used keys are of a size wherein the opposite surfaces are spaced apart by 100 mils, so each side of the hexagon has a length C of 57.75 mils. The module shifts a distance of about 10 mils when it is clamped. The gap distance B between mating interfitting key sides 94P, 96P previously has been about 20 mils, to allow for sideward shifting of one key by 10 mils and to allow for combined tolerances of 10 mils. In this example, the top surface contact area 112P is 0.116mm2 (1.8x 10�4 inch2).
The major advantage of the arrangement of FIG. 7, is that the forward parts 120, 124 of the two keys lie only 8 mils apart during the beginning of mating. If a mismating key 136 (FIG. 8) is installed, whose center point 140 is angled by only 60� from the center point 142 of a properly mating key, then the top surfaces 138, 139 of the keys interfere in an area 144 which is considerable. In the above example where the length C of each hexagon side is 57.75 mils, and the gap distance E of the front parts is 8 mils, the top surface contact area 144 is 0.348mm2 (5.4x 10�4 inch2). For stainless steel keys with a Brinell hardness of 150Kg/mm2 this contact area will sustain a load of 115 pounds before bearing failure at the contact area. This is sufficient to cause a technician to understand that the connectors are incorrectly polarized. In the prior art key arrangement of FIG. 6, the contact area 112P is 0.116mm2 for a gap width B of 20 mils and 0.177mm2 for a gap width B of 16 mils, or about half the contact area 144 (FIG. 8) for the present key arrangement.
FIG. 9 is a perspective view of a pair of keys 61x, 62x of the same type as the keys 61, 62, but rotated 180� about the key axis 74. It can be seen that the third and fourth surfaces 75, 77 of the key are longer at the forward key part 116 than at the rearward key part 118 (in lateral directions L that are perpendicular to a forward direction F). The keying portion 90 of each key extends in a forward direction F from the mounting portion 80.
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS977836 *Apr 25, 1910Dec 6, 1910Clarence D PlattFixed-polarity attachment-plug.US3491330 *Sep 22, 1967Jan 20, 1970Amp IncConnector keying systemUS3611272 *Jul 1, 1970Oct 5, 1971Bendix CorpPolarizing means for mateable units such as electrical connectorsUS4778411 *Apr 24, 1987Oct 18, 1988Amp IncorporatedRetention system for connector key member* Cited by examinerReferenced byCiting PatentFiling datePublication dateApplicantTitleUS5370557 *Oct 22, 1993Dec 6, 1994The Whitaker CorporationKeying system for low profile connectorUS5769669 *Aug 26, 1996Jun 23, 1998Dsc Telecom L.P.Apparatus and method for keying an electrical assembly with a wiring backplaneUS6869319 *Oct 31, 2003Mar 22, 2005Ddk Ltd.Misconnection-proof key and connector using the sameUSRE42318 *Apr 4, 2006May 3, 2011Rambus Inc.Semiconductor module with serial bus connection to multiple diesUSRE42429 *May 28, 2010Jun 7, 2011Rambus Inc.Semiconductor module with serial bus connection to multiple diesUSRE42785May 28, 2010Oct 4, 2011Rambus Inc.Semiconductor module with serial bus connection to multiple diesEP0576857A1 *Jun 3, 1993Jan 5, 1994Siemens AktiengesellschaftCoding means for electrical devicesEP0578180A1 *Jul 5, 1993Jan 12, 1994Framatome Connectors InternationalConfigurable coded electrical plug and socketWO2007059799A1 *Dec 5, 2005May 31, 2007Framatome Connectors IntConnector system with keying members* Cited by examinerClassifications U.S. Classification439/681International ClassificationH01R13/645Cooperative ClassificationH01R13/6453European ClassificationH01R13/645BLegal EventsDateCodeEventDescriptionFeb 1, 2000FPExpired due to failure to pay maintenance feeEffective date: 19991119Nov 21, 1999LAPSLapse for failure to pay maintenance feesJun 16, 1999REMIMaintenance fee reminder mailedMay 1, 1995FPAYFee paymentYear of fee payment: 4Oct 22, 1990ASAssignmentOwner name: ITT CORPORATION, A CORP. OF DE, NEW YORKFree format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:WELSH, DAVID E.;REEL/FRAME:005592/0537Effective date: 19901005RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services©2012 Google