US3813635A - Terminal connector - Google Patents

Abstract

To provide a large contact area and rigid high pressure connection between a heavy power carrying terminal and a power distribution bus, capable of being thoroughly insulated with water-impervious material, a tapered or inverted frusto-conic socket is suitably machined or incised into the bus and a terminal having a similarly tapered shank is press-fitted into the socket. A clearance bore through the shank receives a bolt for connection through a receiver in the bus located beneath the conic socket. An arched washer may be used under the head of the bolt to maintain a high pressure engagement between the terminal shank and the bus during changing thermal or vibratory conditions. The entire connection area may then be jacketed with a double jacket, the jacket serving to insulate the bus and connection in a water-impervious, sealing fashion.

Description

United States Ptent [191' Cooper, Jr. et a1.

1 1 TERMINAL CQNNECTOR [75] lnventors: James Joseph Cooper, ,lr.; Gary Lee Schurter, both of St. Louis, Mo.

[73] Assignee: International Telephone and Telegraph Corporation, New York, N.Y.

22 Filed: June 9, 1972 [21] Appl. No.: 261,539

Related US. Application Data [62] Division of Ser. No. 80,339, Oct, 13, 1970, Pat. No.

[52] US. Cl. 339/22 B, 339/242, 339/263 R [51] Int. Cl H011 13/60 [58] Field of Search 339/242, 22 B, 19, 263 R, 339/263 B, 263 E, 263 L, 263 S, 267, 268 R, 268 S, 213, 270

[56] References Cited UNITED STATES PATENTS 2,087,384 7/1937 Lee 339/270 R 3,183,476 5/1965 Sacks et al Hawkins Sievert 339/22 1 1 May 28, 1974 3,633,147 l/l972 Polidori 339/19 Primary Examiner-.loseph H. McGlynn Assistant Examiner-Robcrt A. Hafer Attorney, Agent, or Firm-James B. Radon; Marvin M.

Chaban [57] ABSTRACT To provide a large contact area and rigid high pres sure connection between a heavy power carrying terminal and a power distribution bus, capable of being thoroughly insulated with water-impervious material, a tapered or inverted frusto-conic socket is suitably ma- .chined or incised into the bus and a terminal having a similarly tapered shank is press-fitted into the socket. A clearance bore through the shank receives a bolt for connection through a receiver in the bus located beneath the conic socket. An arched washer may be used under the head of the bolt to maintain a high pressure engagement between the terminal shank and the bus during changing thermal or vibratory conditions. The entire connection area may then be jacketed with a double jacket, the jacket serving to insulate the bus and connection in a water-impervious, sealing fashion.

3 Claims, 8 Drawing Figures PATENTEDW 28 m:

SHEEI 1 BF 2 PATENTEB m 28 1915 SHEEI 2 OF 2 FIG. 7 /II I TERMINAL CONNECTOR This is a division of application Ser. No. 80,339 filed October 13, 1970, now US. Pat. No. 3,699,497.

BACKGROUND OF THE INVENTION Where a terminal or plurality of terminals are to be connected to a heavy power carrier such as a central bus, the general practice has been to drill or otherwise produce a cylindrical socket in the bus surface and thread or tap the socket to receive a shoulder stud terminal. The shoulder on the stud contacts the bus surface to produce a surface to surface contact while further contact is made through the mating contacts. In these devices, the contact surface is limited primarily to that of the shoulder-to-bus contact while the contact through the threads is minimal. The amount of contact surface limits the current carrying capacity of the connection, and the contact maybe diminished even further due to mechanical vibration or thermal changes.

In another form of connector known to the art, a clearance opening is drilled or otherwise machined or formed through the bus, and a screw receiving socket is threaded into the underside of the terminal. A bolt is passed through the clearance opening and is tightened into the terminal. Again the contact surface is formed by the shoulder abutting against the bus upper surface and minimally through the bolt and its contact with the bus lower surface. Again any loosening of the bolt will lead to decreasing the contact pressure between the terminal and the bus, thereby lessening the current carrying capability of the connection. In addition, the protrusions from opposed sides of the bus increase the problems where the bus and terminal are to be insulated in a water-impervious manner.

It is therefore an object of the invention to provide a new and improved high pressure high current carrying connection between a heavy duty bus and one or more terminals.

It is a further object of the invention to provide an improved connector construction for readily connecting one heavy duty terminal to another.

It is a further object of the invention to provide a heavy duty high pressure terminal construction for connection to a central bus to produce a good conductivity, large surface contact between the bus and terminal, relatively impervious to vibration and thermal effects.

It is a still further object of the invention to provide a superior insulating, water-sealed jacket for a heavy power bus and connector.

To effect these and other objects, features, and advantages of the invention, we provide a central bus with an inverted, truncated conic cavity into which is pressfitted the shank of a complementary shaped terminal. A bolt is connected to a receiver firmly secured within the bus and extending into said concavity. A pressure maintaining washer is fitted under the head of the bolt. In this way the complementary conic surfaces provide a large surface area of contact between the bus and the terminal without using the bolt for any appreciable current transfer.

The entire structure can then be jacketed with an interior insulating jacket liner properly sealed to suitable insulating sleeves and double sealed with an outer sealing jacket which can be mated with sleeves, the inner jacket liner and sleeves being of elastomeric material having high insulating properties and superior heat aging and setting characteristics while the'outer jacket is comprised of elastomeric material with high resistance to degradation by oils and abrasion.

Thus, a rigid high pressure connection capable of high power carrying capability is formed, which connection can be maintained even with vibration and thermal cycling.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a section of bus with terminal mounted thereon according to the invention with the insulation and jacketing removed to show the interior structure;

FIG. 2 is a sectional view taken along line 2-2 of FIG. 1;

FIG. 3 is a perspective view of a section of insulating jacket for the connected bus and terminal;

FIG. 4 is a sectional view as FIG. 2 showing the bus connector with terminals, assembled within the insulating jacket;

FIG. 5 is a sectional view of a varient structure of terminals employing the invention;

FIG. 6 is a sectional view of a further variant terminal and bus structure employing the invention;

FIG. 7 is a section view as FIGS. 2, 4, and 6, of an alternate form of terminal and bus structure bearing a cable connected thereto jacketed and sealed; and

FIG. 8 is a view in section along the line 88 of FIG. 3 showing a portion of the fully jacketed terminal, the view of FIG. 8 being showninserted.

Shown in FIG. 1 is an assembled-terminal, shown without insulation, using one form of our invention. In that figure, we show a large rectangular bus 10 onto which has been mounted a terminal 12. The portion of the terminal 12 above the bus is cylindrical in cross section and terminates in a horizontal wall 14 from which the terminal portion 16 upstands. The terminal portion 16 has a circular segmental cross section and spaced along its height has tapped holes 20 for receiving therein screws 22 (not shown in FIG. 1) for connection to the cable which is to be affixed to the terminal in a conventional manner.

Within the center of wall 14 is a circular recess 23 for receiving a mounting bolt 24, the head of which can be seen in FIG. 1. Bolt 24 serves to hold the terminal 12 in firm contact with the bus 10 as will be explained.

In FIG. 2, there can be seen an inverted truncated conic cavity or socket 30 in the bus. The basal section of the terminal 12 has a complementarily shaped shank section 32 to fit within cavity 30 in tight fitting relationship therein. A suitable degree of taper to comprise the shank section may be that of the Morse taper as used in machine tool work. As an example of the amount of taper used and the relative proportions of components found acceptable, we have found that for a bus of 2-% inch height, a terminal shank section which has as its major diameter of l-% inch, a conic section of approximately inch height, and a minor diameter of approxi mately 1- /2 inch provides a suitable contact surface, and easily assembled components. By press fitting the terminal basal section into the bus cavity, a large surface to surface contact area is produced. The contact is enhanced and maintained by the tightening of bolt 24 within a suitably threaded socket 34. A crowned or arched washer 36 of the type sold under the tradename Belleville" washer is inserted under the head of the bolt 24 prior to mounting of the bolt to sustain a pressure fit between the terminal base and the bus cavity.

In FIG. 3, we show a single jacket 40 of suitable insulating, water-impervious material. The jacket 40 as shown has a rectangular through opening 42 sized to receive with a clearance fit the bus 10. The jacket has spaced tubular risers 44, extending upwardly from the top jacket wall 45, there being open communication between the through opening 42 and the tubular bores 46 of risers 44. The bore spacing would correspond to the spacing between terminals to be mounted on the bus, and the bores must be sufficiently large to encircle a terminal, once assembled in the manner shown in FIG. 4. Annular shoulders at the rim of the bores serve to receive and mate with a suitable insulating sleeve, if desired. An end plug or cap 48 is fitted into the end of the opening 42 to close the opening and complete the insulation surrounding the bus.

In FIG. 5, we show how our invention may be used to connect together two tubular crimp sleeves with a rigid high pressure electrical contact between the sleeves. A first of the crimp sleeves 60 has a circular end wall or floor 62 at one end. The outer surface of the end wall 62 has an inverted truncated conical cavity 64 formed therein. The other sleeve 66 has a truncated cone 68 extending outwardly from its circular end wall 70. The truncated cone 68 and cavity 64 are complementarily sized and shaped in the manner previously described for FIGS. 1 and 2. Thus, the bolt 72 readily fits within the tubular opening 75 at the center of the crimp sleeve 70. Cone 68 fits into cavity 64 with a press fit insuring large area surface to surface contact. A suitable bolt 72 in one sleeve end wall fits into a suitably threaded hole 73 in the wall of the other sleeve and a compression maintaining washer 74 is mounted under the bolt head.

In FIG. 6, we show how two terminals 120 and 12b can be connected to a bus a using a single bolt 24a with the terminals mounted on both sides of the bus opposed cavities of the same shape as previously described, i.e. truncated conic sockets, are formed or machined in the bus 10a, the sockets 30a and 30b being of desired size and configuration for the terminal to be attached. Preferably sockets 30a and 30!) would have the same size and configuration with a clearance opening coaxial to both sockets. One terminal 30a has a central clearance opening 80; The other terminal 3012 has a threaded receiver opening 82 in its communication with a suitable bus clearance opening 84 to receive a single bolt 24a holding both terminals firmly in contact with the bus. Again a holding crowned washer 36a fits under the head of bolt 34a, to tightly hold the terminals together.

The drawings in general have shown a single socket in each bus 10. Using our principle, we could of course provide and show a plurality of sockets in the bus, as indicated by FIG. 1, and a like number of terminals mounted therein. The principle, of course, remains the same.

Similarly in describing the insulating jacket of FIG. 3, it is clear that the jacket would be slid onto the bus prior to the mounting of terminals or terminals on the bus. The jacket bores would then be aligned with the sockets and the terminals affixed. The jacket could require one end plug or two end plugs, dependent on whetherthe jacket had been fabricated with one solid end wall or with both ends open.

In FIGS. 7 and 8, we show an alternate form of assembly fully jacketed and sealed, employing our inventive concept. There we show a section through our bus bar 1 10 to which there is connected a tapering terminal 112 fitted therein within a truncated conic cavity 111 in bus 110. The terminal 112 has extending therethrough a central cylindrical bore 114 which extends from one terminal surface 113 concentrically through the terminal for most of the terminal height and leads into a central bore 116 of smaller diameter. The lower end of bore 114 is filled with a core plug 118 having threaded fit into bore 114. The core plug may also be welded to the terminal 112 if desired. The plug is cylindrical in shape and its lower surface remains coplanar with the bottom surface 113 of the terminal. A central clearance hole in the plug bears a headed bolt 132, the bolt head resting in bore 114 between plug 118 and the decreased diameter of bore 116. The socket type bolt head 134 is accessible through the bore 116 for tightening the screw into a suitably threaded hole in the bus bar concentric with the conic cavity 111.

The terminal and bus connector assembly is insulated and sealed with a composite molded insulating jacket comprised of composite molded end plugs 151 for the jacket; composite, molded, slip-over self-sealing insulating sleeves 152 for the cable and cable connection, and bus cover 154. All insulating components of this system include a molded inner liner of double thickness fabricated of an elastomeric material having high dielectric strength and good physical properties such as elasticity and resiliency, especially concerning permanent set characteristics in conjunction with heat aging. The outer casing 162 of all the components is also an elastomeric material, this material having high resistance to degradation by oils and excellent resistance to abrasion.

At the junction or sealing area 164 where end plugs 151 are assembled to the bus cover 154, or at sealing area 166 the insulating sleeves 152 are assembled to the bus coating 154, the inner lining material 160 of any component always bears sealingly against the inner lining material of the mating component and the outer casing material always bears against seals to the outer casing of the mating component. Further the inner lines 170 of sleeves 152 may have annular sealing ribs adjacent each end and in addition the outer liner 172 annular sealing ribs for sealing to the cable 114. Further, the bus cover 154 as shown in FIG. 7 has an annular depression 176 for receiving enlarged rib 180 of the sleeve to complete the sealing arrangement. In this manner, a mating U-shaped joint is formed by the outer and inner liners of one member into which joint the outer and inner liners of the other member matingly fit.

In this way, the entire bus connector with sleeves, when installed in service, is compatible with and truly an extension of the presently used and acceptable insulating system used on network underground conductors. This insulating system, which includes the slipover self-sealing sleeves, thereby eliminating the costly taping operation generally required on network connector design. The use of slip-over sleeves no longer makes the integrity of the sealing areas solely dependent on the ability of the installer to fabricate a seal with tape. The thick, molded-on outer casing would overcome problems prevalent with dip coated outer jackets where incomplete coating may occur leading to the ever present possibility that the thin coating may be easily damaged during installation, thus exposing the inner electrical insulation and making it susceptible to damage by oil. The sealing arrangement disclosed herein between the bus jacket and the self-sealing insulating sleeve permits a simplification in mold design and reduces the size of the insulating sleeves and end plugs, but permits the extension of the cable insulation feature into the bus connector assembly.

While there has been described what is at present thought to be the preferred embodiments of the invention, it is understood that modifications may be made therein, and it is intended to cover in the appended claims all such modifications which fall within the true spirit and scope of the invention.

We claim:

l. A power distribution connection for joining two terminal members comprising an inverted, frusto-conic blind socket in one wall of a first conductive terminal member, a shank on a second terminal member, said shank including a frusto-conic section shaped and sized for press-fitting relationship within said frusto-conic socket, said socket being greater in depth than the penetration depth of said shank to allow said shank to be compressively seated within said conic socket to produce a large conic area of surfaceto-surface contact between said terminal members to render said contact capable of carrying currents of over 1,000 amps, conductive means extending through said one wall of said first conductive member and the base of said frustoconic shank for permanently connecting said shank within said socket, and means for maintaining a high compressive force in said surface contact between said terminal members, wherein said permanent connecting means comprises a threaded fastener extending through the base of the frusto-conic shank of said second terminal member and a threaded receiver on the other terminal member, and further includes a biasing member maintaining relatively constant pressure between said shank and said socket.

2. The connection of claim 1, wherein there is a onepiece insulating cover disposed about said first terminal member, said cover being imperforate on the side opposite said second terminal member.

3. The connection of claim 1, wherein said connecting means comprises a bolt passed through said second terminal member, and a threaded member facing said socket for receiving said bolt.

Claims (3)

1. A power distribution connection for joining two terminal members comprising an inverted, frusto-conic blind socket in one wall of a first conductive terminal member, a shank on a second terminal member, said shank including a frusto-conic section shaped and sized for press-fitting relationship within said frusto-conic socket, said socket being greater in depth than the penetration depth of said shank to allow said shank to be compressively seated within said conic socket to produce a large conic area of surface-to-surface contact between said terminal members to render said contact capable of carrying currents of over 1,000 amps., conductive means extending through said one wall of said first conductive member and the base of said frustoconic shank for permanently connecting said shank within said socket, and means for maintaining a high compressive force in said surface contact between said terminal members, wherein said permanent connecting means comprises a threaded fastener extending through the base of the frusto-conic shank of said second terminal member and a threaded receiver on the other terminal member, and further includes a biasing member maintaining relatively constant pressure between said shank and said socket.

2. The connection of claim 1, wherein there is a one-piece insulating cover disposed about said first terminal member, said cover being imperforate on the side opposite said second terminal member.

3. The connection of claim 1, wherein said connecting means comprises a bolt passed through said second terminal member, and a threaded member facing said socket for receiving said bolt.

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