TERMINAL PIN AND END CLOSURE STRUCTURE FOR A HOUSING OF A HERMETIC TERMINAL ASSEMBLY, AND METHOD OF MANUFACTURE

Abstract: A modified terminal pin (19) and end closure structure for the housing (4) of an hermetic terminal assembly and method of manufacturing the same is described. The closure structure includes an apertured end closure (2) with a peripheral wall (12) surrounding the aperture (11) and extending into the housing (4) with the free end of the wall (12) cooperatively overlapped in aperture sealing relation by a terminal pin carrying eyelet (13)

Description: The present invention relates to hermetic terminal assembly structure and particularly to an end closure structure for the chamber defining housing of a hermetic terminal assembly, the end closure having an aperture therein to provide for a terminal pin carrying eyelet cooperatively sealed to the end closure along the periphery of the aperture. As discussed in EP-A-0 263 050 it is well known in the art to place an apertured cover in a fixture, the fixture further supporting in the cover aperture a terminal pin surrounded by an annular bead of glass or glass sinter extending from the pin to the aperture wall, the loaded fixture being heated to the melting point of the glass to bond the glass to the cover and to the pin. More recently, to reduce space, time and energy requirements and to avoid cumbersome manufacturing techniques, a universal seal has been provided in the form of a pin carrying eyelet which can be readily oriented in either of two positions in sealing relation with the aperture of the cover for efficient and economical assembly and welding. This known type universal seal is disclosed in US-A-4 603 095. The pin carrying eyelet has chamfered edges. For welding the eyelet to the end closure or cover one of the chamfered edges is placed in contact with a sharp arras defining the margin of the aperture in the end closure or cover. It is also known from US-A-3 219 753 and 4 233 372 to provide surface to surface contact between a pin carrying eyelet and a cover to which the eyelet is to be welded. The glass seal is spaced axially of the pin from the weldment between the eyelet and the cover. The object of the invention is to provide a terminal pin and end closure structure, having an improved strong weld seal and support between the eyelet and the end closure while maintaining optimum compactness. In accordance with the invention, to achieve this, there is provided a terminal pin and end closure structure for a chamber defining housing of a hermetic terminal assembly, comprising an end closure including a main body having an aperture therein, a projection surrounding the aperture, being integral with the main body and extending at an angle with respect thereto, a substantially flat eyelet geometrically sized to conform with and totally cover said aperture in said end closure, said eyelet having opposed parallel side faces with an aperture disposed therethrough, and a chamfered peripheral edge face adjacent at least one side face, with said chamfered peripheral edge face being in fuse welded sealed relation with said projection, and a terminal pin sealed in said aperture of said eyelet to extend beyond said opposed faces of said eyelet, characterized in that said projection is an extended peripheral wall presenting inner and outer edges at its free extremity, that said chamfered edge face abuts said inner edge of said extended peripheral wall providing line contact therebetween along the entirety of the circumferential extent of the chamfered edge face (23) and the inner edge of said extended peripheral wall (12), and that said extended peripheral wall extends toward said housing chamber when said end closure is assembled therewith. The present invention provides an improved end closure structure for the chamber defining housing of an hermetic terminal assembly which employs certain features of EP-A-0 263 050 in a modified form to even further increase the advantages of reducing space, time, material and energy requirements, avoiding cumbersome manufacturing steps, improving the joining of a pin carrying sealing member such as an eyelet to the cover, and even further increasing both the strength of the jointure and the structural support and assured positioning of the terminal pin relative the cover to which it is assembled. As in EP-A-0 263 050, the present invention provides a structure particularly suited for use with thinner covers, even further contributing to overall size and weight reduction of the hermetic terminal assembly and further increasing overall strength and terminal pin support. The present invention provides a compact, comparatively light and strong assembly structure that also is particularly suited for lithium type batteries. Referring to the drawing which discloses an advantageous embodiment of the terminal pin and end closure structure: Figure 1 is a plan view of the novel apertured end closure structure for a chamber defining housing of an hermetic terminal assembly; Figure 2 is an enlarged cross-sectional view of the end closure structure of Figure 1, taken in a plane through line 2-2 of Figure 1, disclosing a portion of the hermetic terminal assembly housing; and, Figure 3 is a further enlarged cross-sectional view of a portion of the structure of Figure 2, disclosing details of the end closure and eyelet prior to welding. As can be seen in the drawing, the novel end closure 2 includes a circular main body 2 having a peripheral rim 3 extending normally from the main body thereof, rim 3 being sized and geometrically configured to conform with the inner face of cylindrical chamber defining housing 4 to snugly fit thereagainst and to be sealed thereto. As can be seen in Figure 2, the peripheral rim 3 is so positioned in housing 4 that the outer extremity of peripheral rim 3 conforms with the outer extremity of chamber defining housing 4. When rim 3 has been properly positioned in housing 4, it can be sealed thereto by any one of a number of suitable sealing means depending upon the materials involved, such as by laser or TIG (tungsten inert gas) welding when the materials are fusible metals. As can be seen in Figures 2 and 3 of the drawing, the main body of end closure 2 includes substantially parallel integral offset radially inner section 6 and radially outer section 7 joined by connecting wall 8 integral therewith so that, when end closure 2 is assembled with housing 4, the inner section 6 is spaced from chamber 9 defined by housing 4 a greater distance than outer section 7, the offset further serving to enhance the strength and stability of the end closure. Inner section 6 is provided with an aperture 11 therethrough and an extended peripheral wall 12 surrounding aperture 11 to extend substantially normal thereto toward outer section 7 and housing chamber 9 when end closure 2 is assembled to housing 4. End closure 2 is formed from a suitable fusible stock material and, when the end closure is to be for lithium type battery assemblies, advantageously is formed from a suitable thin metallic material such as stainless steel strip stock, designated commercially as 304L SS having a thickness of approximately 0.25 ± 0.025 mm (0.010 ± 0.001 inches). Sized to conform with and overlap the free end of extended wall 12 in cooperative sealed relation therewith to cover aperture 11 is eyelet 13. Eyelet 13, like end closure 2, can be formed from a suitable fusible material companionable with the fusible material of end closure 2 and in lithium type battery assemblies advantageously is of the same steel stock as end closure 2. Eyelet 13 has substantially flat, parallel surfaces 14 and 16, is circular and is sized to conform with and cover aperture 11 in end closure 2. Eyelet 13 has a central aperture 17 defined by an inner cylindrical wall 18 to which a terminal pin 19, extending substantially normal to surfaces 14 and 16, is bonded by means of a suitable seal 21, which can be of a preselected glass formulation. The outer margins of eyelet 13 are defined by an outer wall 22, perpendicular to parallel planar eyelet surfaces 14 and 16 and chamfered perimetric edge faces 23 and 24, extending at mirror-image angles from the opposite perimetric edges of outer wall 23 to eyelet surfaces 14 and 16 respectively. As in EP-A-0 263 050, the angles of the chamfered faces can be identical and the chamfers symmetrical on either planar surface. It is to be noted that chamfered edge face 23 abuts against the inner free edge of peripheral wall 12, it being understood that it would also be possible to have chamfered edge face 24 so abutting the inner free edge of peripheral wall 12, the abutment, in either case, forming a line contact between the chamfered edge face and the peripheral wall edge. The distance between outer planar surfaces or faces 14 and 16 of eyelet 13 or the thickness thereof is substantially equal to the offset distance between inner section 6 and outer section 7 of the main body of end closure 2 or the breadth of connecting wall 8. Thus, when most of peripheral wall 12 is fused as part of the seal, eyelet surface or face 16 lies substantially in the same plane as outer section 7 of the main body of end closure 2 to enhance compactness of the assembly. It is further to be noted that terminal pin 19 sealed in aperture 17 of eyelet 13 and extending normally beyond faces 14 and 16 thereof is so sized that one extremity of pin 19 extends between the outer surface of inner section 6 of the main body of end closure 2 and the extremity of housing 4 when the end closure is assembled therewith. Thus, not only is compactness enhanced, but the pin 19 does not interfere if the housing is rested on such extremity. In manufacture of the end closure structure above-described, the main body portion of end closure 2 can be formed by some suitable means such as stamping and punching in a manner similar to that described in EP-A-0 263 050 only in this structure the formation is such that the main body includes offset inner section 6 and outer section 7, the outer section having peripheral rim 3 and the inner section having aperture 11 with an integral peripheral wall 12 surrounding aperture 11. It is to be understood that other forming steps besides stamping and punching could be employed to arrive at the desired shaped end closure, depending upon the nature of the materials employed. For example, with certain fusible materials, such as plastics, it would be possible to cast or extrude much of the desired shape. Once the end closure 2 has been properly formed, an eyelet 13, including terminal pin 19 extending in sealed relation therethrough, is positioned so that the eyelet 13 covers the aperture in the inner section 6 of the main body of end closure 2 with the peripheral edge face of the sealing means in cooperative abutting relation to the peripheral surrounding wall 12 extending from inner section 6. With the sealing means properly positioned, the peripheral edge face thereof is then joined to the peripheral surrounding wall 12 to form a uniform sealed relation therewith by some suitable sealing step such as fusion resistance, laser or inertial welding in a manner similar to that described in EP-A-0 263 050. From the description set forth above, it is to be understood that, although the present invention lends itself to the effective utilization of very thin end closure structure arranged in a unique compact yet strong manner to resist outward pressures from within a housing chamber, the overall size and overall geometry of the closure is otherwise immaterial as long as the closure aperture and peripheral wall are sized to permit the eyelet, to be securely joined as described, and the relative dimensions of the eyelet thickness and offset of inner and outer sections as well as the terminal pin are such as to permit the desired inventive compactness and facility of handling. As above noted, the end closure and eyelet advantageously can be made of compatible stainless steel but other type metals or conceivably even fusible plastics can be employed.

Claims: Terminal pin and end closure structure for a chamber defining housing of a hermetic terminal assembly, comprising an end closure (2) including a main body having an aperture (11) therein, a projection surrounding the aperture (11), being integral with the main body and extending at an angle with respect thereto, a substantially flat eyelet (13) geometrically sized to conform with and totally cover said aperture (11) in said end closure (2), said eyelet (13) having opposed parallel side faces (14,16) with an aperture (17) disposed therethrough, and a chamfered peripheral edge face (23) adjacent at least one side face (14), with said chamfered peripheral edge face (23) being in fuse welded sealed relation with said projection, and a terminal pin (19) sealed in said aperture (17) of said eyelet (13) to extend beyond said opposed faces (14,16) of said eyelet (13), characterized in that said projection is an extended peripheral wall (12) presenting inner and outer edges at its free extremity, that said chamfered edge face (23) abuts said inner edge of said extended peripheral wall (12) providing line contact therebetween along the entirety of the circumferential extent of the chamfered edge face (23) and the inner edge of said extended peripheral wall (12), and that said extended peripheral wall (12) extends toward said housing chamber (9) when said end closure (2) is assembled therewith. Terminal pin and end closure structure according to claim 1, characterized in that said peripheral wall (12) extends normal to said end closure main body. Terminal pin and end closure structure according to claim 1, characterized in that said end closure main body includes a peripheral rim (3) extending normally therefrom and geometrically conforming with the inner face of said housing (4) to snugly fit thereagainst to be sealed thereto, said rim (3) and said terminal pin (19) being so sized and positioned that one extremity of said pin (19) extends between the outer surface of said main body of said end closure (2) and the housing extremity. Terminal pin and end closure structure according to claim 1, characterized in that said end closure main body includes substantially parallel offset radially inner and outer sections (6,7) with said inner section (6) having said eyelet covered aperture (11) therein spaced from the chamber (9) of said chamber defining housing (4) a greater distance than said outer section (7). Terminal pin and end closure structure according to claim 4, characterized in that said offset difference in spacing from said chamber (9) with respect to said inner and outer sections (6,7) is substantially equal to the thickness of said eyelet (13) sealed to and covering said aperture (11) in said inner section (6). Terminal pin and end closure structure according to claim 1, characterized in that said aperture (11) in said peripheral wall (12) is punch formed in said main body of said end closure (2). Terminal pin and end closure structure according to claim 1, characterized in that said end closure (2) is extrusion formed.

Inventors: BOWSKY, BENJAMIN, BURROWS, LARRY GENE, HONKOMP, GLENN ANTHONY, WILSON, EDWARD EUGENE
Applicants: EMERSON ELECTRIC CO.
Application year: 1987
Main classification: H01M2
IPC codes: H01M2, F16J15