US2238319A - Cable contact - Google Patents

Description

' April 15, 1941 E. R. GoLDFlELD CABLE CONTACT Filed July 12, 1940 I l 24 19ML 19g FIG-2. v

FIG-5 Flc-4 FIG-l INVENTQR EDWIN R. GOLDFIELD A Patented Apr. 15g, 1941 CABLE ooN'racvr Edwin R. Goldileld, University Heights, Ohio, as-

signor to Picker X-Bay Corporation. Waite Manufacturing Division, Inc., Cleveland, Ohio, a corporation of Ohio Application July 12, y1940, Serial No. 345,080 z claims. w1. 17a- 324) 'I'his .invention relates to improvements in electrical cable connectors and particularly to improvements in means for connecting heavy electrical cables :to high `voltage equipment such as X-ray Vtubes and the like.

Electrical connections to high voltage equipment such as X-ray rtubes include very heavy cables sometimes almost an inch in diameter carrying several conductors which are very heavily insulated because of the high voltages carried. For instance it is com-mon in connections to X-ray tubes to use a cable carrying .three conductors, one for the tube anode or cathode, one for the lament and one for 'the return line. These cables are connected to tube equipment which must necessarily be manipulated in the ordinarycourse Yof operations. Such manipula- Y tion requires movement of the connecting cables which, because of their heavy character, arevnot easily distorted. It is very desirable therefore to provide cable connectors permitting a twisting .or rotation of the' cables in their sockets without disturbing the electrical connections. It is also important that such contacts be adapted to carry the high voltages used in a safe manner and tional view` taken along .the line 5 5 of Fig. 4; while Fig. 6 is a sectional view of one of the contact members of Figs. 2 and 3.

In the drawing it will .be understood that the cable I is a cable of the usual character found inX-ray equipment carrying three electrical conductors Il, I2 and i 3, one of which is adapted Ito carry ythe tube current. one for the lament current and one for the return line. Such currents are of the order of 25,000 peak volts or higher. Thesesame currents are carried on to the equipment served by .the connections I4, I5 and I6, leaving the other end of the device here disclosed. It will be understood that the conductors extending beyond the points I4, I5 and I6 are generally oil immersed and the design of my improved connector takes this feature into account.

My novel connector device includes an inner `cylindrical sleeve I1 and an outer cylindrical particularlyto prevent spark-over and corona' effects when the high voltages are used in humid atmosphere or at high" altitudes.

One of the objects of .the present inventionis to provide a novel means for connecting electric cables comprising coacting sets of concentrically arranged intertltting contact members permitting relative rotation betweenl -the movable contact members connected with the electrical cable and `the fixed contact members on the X-ray tube equipment.

Another object of the present invention is to provide a very-.rugged connection of electrical cables with high voltage equipment permitting a .twisting of the cables and at the same time rendering any spark-over practically impossible and housing .the parts in such a manner that they are sufciently ruggedto stand much abuse even to the extent of being dragged through mud and water as is sometimes necessary with army equipment or other emergency use of X-ray apparat/us.

Other objects and advantages of the present invention will be apparent from the accompanyingspeciiication and drawing and the essential features will he set forth in the claims.

In .the drawing, Fig. 1 is an elevational view of pose which'will -be later described.

vat I9.

sleeve I8 having an overall length in the present embodiment of from four to six inches for a pur- The clearance betweenthe outside diameter of sleeve I1 and the inside diameter of sleeve I8 is .lust suilione end of the lcylinder I'Ia and passalong sub.

stantially -the entire length thereof to the free end where the electrical conductors are secured -to a set of contact members indicated generally The contact members are secured to a heavy sheet of insulating material 20 which closes the end of the cylinder 11a and all of thev free space within the cylinder Ila and surroundingv the cable and its conductors indicated generally at ZI is filled with a plastic insulatinf material which lflows readily when heated and stiiens upon cooling. This completely seals and lls the entire space within the cylinder |1a up to the member 20. A spring strip of corrugated metal 22 engages in` recesses Z3 on the inner face of cylinder 11a so as to serve to position the member 20.

Referring nowto the set of contact members indicated generally at I9, this comprises annular substantially rigid contact members Isa, Hb and lSc concentrically arranged. Each of the contact members has portions passing .through the member 2l and bent down on .the inside thereof so as to firmly hold 'the contact members'in place. '.I'he conductors Il, I2 and I3 are soldered to their 'housing associated contact members so as to form .permanent connections. The contact members have longitudinally extending slots as indicated at 24' so as lto provide a slight yielding effect the better to frictionally engage .fthe coacting set of contacts carried by the sleeve I8. A detailed arrangement of the contact member ISb is shown in Fig. 6 where the longitudinally extending slot 24 is extended in T-form as indicated at 24a so as A.to give greater iiexibility at fthe free ends of the contact member.

'Ihe sleeve i8 is threaded as indicated at Ia for attachment to an X-ray tube or to an oil immersion tank carrying the associated equipment. The sleeve also has provided integrally therewith a transversely extending wall IBb which carries centrally thereof a set of contacts indicated generally at 25.

The set of contacts 25 comprises three substantially annular contactmembers 25a, 25h and 25e concentrically arranged preferably in such a manner that they lie radially outside of the respective contact members in the set I9. Referring to the detailed arrangement of Figs. 4 and 5,

the member 25e has a truncated conical surface r 26 which engages a complementary surface of the wall |81, these surfaces being tightly pulled together by a nut 21 threaded on the member 2B, thus holding in place the connector member I5, a washer 28 and a gasket 29. A spacer 30 of insulating material having truncated conical shape spaces the members 25o and 25h. The member 25h is heldassembled by a nu-t 3I which holds in place the connector member I6 and a sheet of insulating material 32. A spacer 33 of insulating material having ltruncated conical form separates the contact members 25h and 25a. The

member 25a has a threaded stem 34 to the lower end of which is attached a nu-t 35 which secures in place the connector member Il and a sheet of insulating material 36. It will be noted that the set of contact members assembled at 25 together with the wall I8b sealsone end of the shell I5 against liquid' leakage from the oil immersion compartment generally connected to the threads Ilia.

When rthe parts are assembled as shown in Fig. 1, the contact members of the set I9 frictionally engage and overlap the contact members of the set 25 with the corrponding membersof d the set 25 lying radially outward of the members of the set I9. The cylinder ila then provides a skirt I'Ic at its inner or free end which engages tightly against the wall 68D, thus overlapping and both sets of contacts and practically preventing any spark-over from them. In any case spark-over travelling from the set of contacts 25 toward the cable I0 would have to travel downwardly as viewed in Fig. 1 for the exposed length of contact member 25c and thenupwardly along the outside of the cylinder Ila. Thus an overlapping of the parts IIc and 25e, by for instance three-eighths of an inch, will compel any sparkover to traverse a path of more than threequarters of an inch, at the same time relative rotation of the contacts I9 and 25 may occur freely without any strains on the cable I0.

The arrangement of the concentric annular contacts I9 and 25 provides a much greater area of coacting contacting surfaces than is found in the customary interengaging prongs of the prior art.

What I claim is:

y1. An electric cable connector comprising inner and outer sleeves of rigid insulating material adapted to have a sliding t one within the other, the clearance between the outside diameter of said inner sleeve and the inside diameter of said outer sleeve being just sufficient to permit sliding movement between the sleeves, said sleeves having a length of approximately four or iive inches. a set of relatively xed contact members, said outer sleeve Ihaving a transverse wall near one end supporting said set of contact members centrally of said sleeve with the contact members extending into the sleeve from said wall, said wall and set and mounting thereforclosing and sealing said sleeve end, electric cable conductors enterlngkat one end of said inner sleeveand extending through substantially its entire 4length to the other or free end thereof, asecond set of con tact members connected to said cable conductors, plastic insulating material sealing said conductors and said second set of contact members within said inner sleeve, leach of said sets of contact members comprising a plurality of concentric members insulated from members in the same set, said sets interfltting and overlapping when said sets are in engagement with the members of the relatively xed set respectively radially outside` the members of the second set, and the free end of said inner sleeve surrounding the outermost contact member of said fixed set and forming a continuous skirt engaging said wall when said sets of contact members are in opera-tive engagement.

2. An electric cable connector comprising male and female members of rigid insulating material, said members being of intertltting cylindrical form "with just suiiicient clearance between the outside diameter of the male member and the inside` diameter of the female member to permit axial sliding movement between them, two frictionally engageable sets of `concentrically `ar ranged contacts, the contacts of each set being electrically insulated from each other, said sets being positioned rigidly one on each of said members in position to be engaged only when said members are in intertting engagement with one member fully within the other, whereby one of said sets of contacts'is at the inner end of said male member, an electrical cable integrally connected with the outer end of said male memberl and having an outer sheath of low potential, said cable having internally thereof a plurality of conductors adapted to carry a current of high potential of the order of 25,000 peak volts, said conductors being integrally joined respectively with the contacts of that set positioned at the inner end of said male member, and said male member being of such a length that there is at least three inches between the set of contacts at the inner end of said male member and the nearest point of the outer sheath of said cable at the outer end of said male member, whereby said cable and male member may be rotated relative to the set of contacts on said female member and when said sets of contacts are engaged the spark-'over or corona effects must travel at least three inches from said contacts through the limited clearance space between said members to reach the nearest exposed point on said cable.

EDWIN R. GOLDFIELD.

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