US3371413A - Hermetically sealed connector - Google Patents

Description

March 5, 1968 D. F. RUNDLE 3,371,413

HERMETICALLY SEALED CONNECTOR Filed 001;. 26, 1966 United States Patent C) 3,371,413 HERMETICALLY SEALED CONNECTOR David F. Rundle, Cicero, Ill., assignor to Amphenol Corporation, Broadview, 11]., a corporation of Delaware Filed Oct. 26, 1966, Ser. No. 589,551

1 Claim. (Cl. 29-629) ABSTRACT OF THE DISCLOSURE A hermetically sealed electrical connector and the method of making it wherein a glass body is interposed between a contact and a steel ring and is in melted-bond relationship with the contact and the ring to produce a hermetic seal therebetween. A metal shell, of a material such as aluminum, is disposed about the steel ring and is engaged to the ring in a heavy force fit accomplished with the shell heated to a predetermined temperature to result in a hermetic seal between the shell and the steel ring.

This invention relates to electrical connectors and more particularly to hermetically sealed electrical connectors and methods of making such connectors.

In electrical connectors it is sometimes desirable that a hermetic seal be effected within the connector about the contacts thereof. Glass is generally used to bond between the connector shell and the contacts to effect the hermetic seal. To insure a good bond between the glass and the connector shell, it has been found that the connector shell should be manufactured from a material that readily oxidizes. Such materials are steel and iron. However, when these readily oxidizable materials are used in the manufacture of a connector, they add substantially to the weight of the connector. Lightweight metals, such as aluminum, do not readily bond to glass since they do not easily oxidize. Accordingly, the state of the prior art does not permit the manufacture of a lightweight hermetically sealed connector.

It is therefore one object of the present invention to provide a lightweight hermetically sealed connector and a method of making such a connector.

It is another object of the present invention to provide a metal to metal hermetic seal and a method of effecting such a seal.

It is another object of the present invention to provide an improved hermetically sealed electrical connector and a method of making such a connector.

Other objects of the present invention will become more apparent as the detailed description proceeds.

In general the present invention comprises a steel ring surrounding an electrical contact. A glass body is interposed of the contact and the glass ring and is in meltedbond relationship with the contact and the ring to effect a hermetic seal therebetween. A metal shell, of a material such as aluminum, is disposed about the steel ring and is engaged to the ring in a heavy force fit effected with the shell heated to a predetermined temperature to give a hermetic seal between the shell and the steel ring.

Further understanding of the present invention may best be obtained from consideration of the accompanying drawings wherein:

FIGURE 1 is a cross sectional view of a connector according to the present invention prior to the final assembly thereof.

FIGURE 2 is a cross sectional view of the connector of FIGURE 1 showing how final assembly is effected.

In FIGURE 1 an electrical contact is mounted within a metal ring 12. A glass body 14 is in melted-bond engagement between the metal ring 12 and contact 10 to effect a hermetic seal therebetween. The contact 10, metal ring 12 and glass body 14, as assembled, form a ring asice sem'bly 16. A metal connector body shell 18 accepts the ring assembly 16 and forms a hermetic seal between the shell 18 and the ring 12.

To effect the aforementioned hermetic seal between the connector shell 18 and ring 12, the connector shell is internally sized so that it will accept the metal ring 12 in a heavy force fit engagement when the connector shell 18 is heated to a predetermined temperature. It is preferred for the present invention that the material of the shell 18 have a lower degree of hardness and a greater coefficient of thermal expansion than the material of the ring 12. Accordingly mild steel and stainless steel are suitable materials for the metal ring 12 and aluminum for the connector shell 18. With these materials, ring 12 will remove material from connector shell 18 upon their engagement and connector shell 18, when cooled, will exert a shrink fit upon the ring 12.

It has been found that an abutment 20 for-med in the connector shell 18 to engage the ring 12 when it is inserted within the shell materially aids in effecting a hermetic seal between the shell 18 and the ring 12. Without the abutment 20, a hermetic seal may still be effected, however, the certainty of so doing is materially reduced. It is to be noted that the material removed from the connector shell 18 by the ring 12 when engaging the shell is compressed against the abutment 20.

The aforedescribed connector assembly is constructed as follows. The periphery 22 of ring 12 is finished to a high grade machine finish (approximately thirty-two microinch finish or better). A preformed glass body is inserted within the metal ring 12 and the contact 10 inserted through the glass body 14. The ring assembly 16 is then heated in an oxidizing atmosphere to a temperature sufficient to melt the glass body 14 and effect bonding thereof to the ring 12 and the contact 10. The ring assembly 16 is then cooled.

As previously stated, the connector shell 18 is internally sized to accept the metal ring 12 in a heavy force fit engagement with the connector shell heated to a predetermined temperature. Further, the connector shell is internally sized so that an abutment 20 is formed therein to engage the ring 12 upon insertion of the ring assembly 16 into the connector shell. The connector shell 18 after the machining is then heated to the temperature at which joining of the ring assembly 16 and the connector shell 18 is to be effected.

The shell 18 while at the aforedescribed temperature is mounted over a support assembly 24 as shown in FIG- URE 2. The ring assembly 16 is mounted in a metal press fixture 26 as also shown in FIGURE 2. The ring assembly 16 may be mounted within the press assembly 26 in several ways. The method illustrated in FIGURE 2 utilizes the socket of contact 10 to effect the mounting. With the press assembly 26 and support assembly 24 coaxially aligned and the connector shell 18 heated to its predetermined temperature, the press assembly 26 is lowered to force fit the ring 12 within the connector shell 18. As soon as bottoming of the metal ring 12 on abutment 20 is effected, the press assembly 26 is elevated to remove the connector shell 18 from support assembly 24 to permit the maximum cooling thereof. As connector shell 18 cools, it will, in addition to the force fit engagement, exert a compressive shrink fit engagement upon the metal ring 12 whereby it has been found a satisfactory hermetic seal is effected between the connector shell 18 and the metal ring 12.

If mild steel is used for the metal ring 12, it is generally desirable, after completion of the ring assembly 16, for a protective plating to be deposited upon the ring 12 to prohibit corrosion thereof. If such is done, then the amount of metallic deposition on the periphery 22 of ring 12 should be taken into consideration in calculating the internal sizing of the support assembly 24 to insure the aforedescribed heavy'force fit.'If stainless steel is used for the metal ring 12, it is desirable that, prior to melting of the glass body 14 to form ring assembly 16, the ring 12 be copper plated to-inhibit oxidation of the surface thereof during the-formation of ring assembly 1t. Therefore, with stainless steel, the metal ring 12-should be cop per plated "'and'any copper deposited on interior surface 128 ofthe ring -be'removed by'rnachining prior to-melting phere'to effectthehermetic ring assembly 16. The connector shell '18 was internally sizedto a nominal diameter of 1.050 inches. This nominal diameter gave the shell 18 an internal diameter which was'two thousandths of an inch less than the 1.0615 diameter of the ring 12'when the connector shell 18 was at a'temperature of"650 F. The connector shell Washeated in an oven tothe'650 F. temperature and then rapidly transferred to the support 'assembly24 shown in FIGURE 2. The ring assembly 16 was'imrnediately brought into engagement with the connector'shell 18 until' motion was arrested by abutment 20. The shell 18 was then removed from the support assembly'24'and gave a satisfactory hermetic seal between the metal ring 12 and connector shell 18 and between the glass'body '14,-metal ring 12 and contact 10. It is to be understood that'though the foregoing example heated' the connector shell'18 apart from the support assembly 24, that such heating maybe effected while on the support assembly.

Persons skilled'inthe art will, of course, readily adapt the teachings of the present invention to embodiments and methods far different than the embodiment and method described above. Accordingly, the scope of protection afforded the present invention should be determined only in accordance with the appendedclaim.

The embodiments of the invention in which an exclusive property or privilege-isclaimed are defined as follows:

=1. A-method of making a hermetically'se'aled' electrical connector comprising finishing the periphery of a stainless steel ring to a high grade machine finish; copper plating said ring; removing the copper plate from the interior surface of said ring; inserting an electrical contact within a glass'body;inse'rting said glass'body within said ring to form a ring assembly; heating said ring assembly-to a predetermined temperature in an oxidizing atmosphere to melt said glass body and form a hermetic seal between said glass body, said contact and said ring; removing the copper plating from said ring; sizing the interior of an aluminum shell to-accept said ring to a predetermined depth therein in a heavy force fit engagement with said shell at a predetermined temperature; heating said shell to said predetermined temperature; coaxially engaging said ring assembly and said shell in a heavy force fit engagement with-said shell at said predetermined temperature to said predetermined depth; and rapidly cooling said shell whereby said shell shrinkfit engages said ring.

References Cited UNITED STATES PATENTS 5 79,969 4/ 1897 Fellows 29'-447 2,272,210 2/ 1942 King "29- 447 X '3,070,649 12/1962 Edlen et a1 .."339'89 X FOREIGN PATENTS 872,580 7/ 1961 Great Britain.

LARAMIE EVASKIN, Primary Examiner.

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