US3730970A - Terminal with grease retaining members - Google Patents

Terminal with grease retaining members Download PDF

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Publication number
US3730970A
US3730970A US00185990A US3730970DA US3730970A US 3730970 A US3730970 A US 3730970A US 00185990 A US00185990 A US 00185990A US 3730970D A US3730970D A US 3730970DA US 3730970 A US3730970 A US 3730970A
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US
United States
Prior art keywords
terminal
chamber
insulated conductor
inlet end
retaining member
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00185990A
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English (en)
Inventor
L Johnson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
3M Co
Original Assignee
Minnesota Mining and Manufacturing Co
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Filing date
Publication date
Application filed by Minnesota Mining and Manufacturing Co filed Critical Minnesota Mining and Manufacturing Co
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Publication of US3730970A publication Critical patent/US3730970A/en
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02G—INSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES
    • H02G15/00—Cable fittings
    • H02G15/02—Cable terminations
    • H02G15/06—Cable terminating boxes, frames or other structures
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02G—INSTALLATION OF ELECTRIC CABLES OR LINES, OR OF COMBINED OPTICAL AND ELECTRIC CABLES OR LINES
    • H02G15/00—Cable fittings
    • H02G15/02—Cable terminations
    • H02G15/06—Cable terminating boxes, frames or other structures
    • H02G15/064—Cable terminating boxes, frames or other structures with devices for relieving electrical stress
    • H02G15/068—Cable terminating boxes, frames or other structures with devices for relieving electrical stress connected to the cable shield only

Definitions

  • ABSTRACT I A terminal for high voltage electrical cable formed 5 6] References Clted with a chamber extending through the terminal from UNITED STATES PATENTS an inlet end for engagement over the cable to an out- 2,946,839 7/1960 Horning ..174 93 let i g g g i i T g l a 3,044,037 7/1962 Honig ..174 93 X 9 e c am er mm c m en 5 e 3 065 292 11/1962 Chickvary .174/93 xmeans Operable of the 3,231,524 10/1966 Lynch).
  • Terminals of the type described in US. Letters Patent No. 3,542,942 are formed with a chamber having an inlet end for insertion of the cable end to be ter- 1 "end of the chamber which is attached to the semi-conductive sleeve of the cable as this area experiences the greatest electrical stress.
  • Assembly of the shielded conductor with the terminal typically comprises threading the end of the cable through the partially grease-filled chamber.
  • insulating grease in the chamber tends to move through I the chamber with the cable leaving air pockets, particularly adjacent the inlet end of the chamber. Air within these tiny pockets is ionized by the high electrical stress, producing a chemical and mechanical breakdown in the surrounding insulating-grease or cable insulation. This breakdown will progress until the insulative property of the cable insulation and insulating grease is destroyed and the high voltage carried by the conductor arcs to an available ground.
  • a terminal according to the present invention provides means for insuring essentially air-pocket-free insulating grease in the chamber about the cable for a predetermined distance from the inlet end of the chamber.
  • a terminal for a high voltage electrical cable is formed with a chamber having an outlet end and an inlet end adaptable for engagement over the cable.
  • a viscous electrically non-conductive grease fills a portion of the chamber from the inlet end, and retaining means is mounted in the chamber for retaining the grease in the chamber about the cable between the retaining means and the inlet end upon threading of the cable into the chamber from the inlet end.
  • FIG. 1 is a vertical sectional view'of a terminal constructed according to the present invention connected to an electrical cable;
  • FIG. 2 is a fragmentary vertical sectional view of a terminal as shown in FIG. 1 prior to assembly with the electrical cable;
  • FIG. 3 is a perspective view of a first retaining member used in the terminal shown in FIGS. 1 and 2;
  • FIG. 4 is a perspective view of a second retaining member used in the terminal shown in FIGS. 1 and 2.
  • the electrical cable 12 is of the type having a central conductor 14, and aninsulating sleeve 16 between the conductor 14 and a cylindrical semiconductive shield 18.
  • the device 10 is useful for terminating the semi-conductive shield 18 where a continuing length 20 of the insulated conductor 14 is to be connected to a second conductive member (not shown) at a connector element 21 attached to the conductor 14.
  • the insulating sleeve 16 is typically formed of a polyethylene or cross-linked polypropylene materi- 0 a1; and the semi-conductive shield 18 is typically comprised of a semi-conductive ethylene propylene material.
  • the cable 12 may have a multiplicity of ground wires 22 wrapped around the semi-conductive shield 18 to afford an efficient path to ground from the shield 18 and to providemechanical strength for the cable 12.
  • the terminal 10 includes wall means for defining a chamber 24 within the terminal 10 and having an inlet end 26 adapted for engagement with the cable 12.
  • the wall means includes a boot or semi-conductive stress relief cone member 28 for shaping the electrical stress lines, having an internal wall 30 defining a funnel-shaped bore 32.
  • the wall 30 adjacent the small end of the bore 32 defines the inlet end 26 adapted for engagement with the end 33 of the semi-conductive shield 18 to position the continuing length 20 of the insulated conductor 14 centrally projecting from the large end 34 of the bore 32.
  • the semi-conductive member 28 is formed of a flexible, resilient elastomeric material having less than 1 megohm per square centimeter resistance (such as Nordel" conductive ethylene-propylene terpolymer) to continue the semi-conductive electrical path of the shield 18 onto the device 10.
  • the wall 30 adjacent the inlet end 26 is formed with annular sealing grooves 38 for an air tight seal about the shield 18, and conforms to engage the end of the semiconductive shield 18.
  • wall 30 adjacent the large end of the bore 32 is formed with inwardly extending parallel spaced ridges 40 engageable with mating grooves formed about a hub on one end of a porcelain insulator 42.
  • the surface of the insulator 42 contacted by the semi-conductive member 28 is coated with a conductive material to prevent ionization of air in any voids left therebetween.
  • a grounding insulator support clamp 43 attached to the ground wires 22 may be engaged about the end of the semi-conductive member 28.
  • the insulator 42 is formed with a cylindrical bore 44 of larger diameter than the insulating sleeve 16 and is attached to the semi-conductive member 28 with the bores 44 and 32' axially aligned to concentrically position the continuing length 20 of the insulated conductor 14 within the cylindrical bore 44.
  • the outer surface of the insulator- 42 is formed along its length with a series of rings 46 to provide a long surface path between the conductor element 21 and the grounding clamp 43 to restrict arcing therebetween.
  • the bores 32 and 44 form the chamber 24 within the terminal 10.
  • the outlet end of the chamber 24 opposite the semi-conductive member 28 is defined by a central opening through a resilient sealing cup 48 engaging the end of the insulator 42 and an' outer stainless steel cap 49.
  • the connector element 21 projects through the central opening in the cup 48 and. cap 49 and is held in that position by a snap ring 50.
  • a viscous, thixotropic electrically insulating grease 52 having a high dielectric strength is provided onlyin sufficient volume to fill the voids remaining in the chamber 24 for a predetermined distance from its inlet end 26, which distance isless than the length of the chamber 24, after the cable has been inserted (FIG. 1 Prior to engagement with a power cable 12 the grease fills a portion of the chamber 24 extending from the inlet end 26 of the chamber 24 (FIG. 2).
  • a removable plug 54 engageable with the inlet end 26 is provided to protect the grease 52 prior to use of the terminal 10.
  • Retaining means or retaining members 56 and 58 are mounted in the chamber 24 for retaining the grease 52 in the chamber 24 about the continuing length of cable 12 between the retaining member 56 or 58 and the inlet end 26 upon threading of the cable 12 through the chamber 24 from the inlet end 26.
  • the retaining member 56 as best seen in FIG. 3 has wall means forming a hollow truncated conical wall 60 defining an orifice 62 at its small end and an annular lipped flange 64 formed about the large end thereof for engagement with the end of the hub on the insulator 42 and the wall 30 for retaining the grease 52 between the retaining member 56 and the inlet end 26 of the semiconductive member 28.
  • Suitable materials for forming the retaining member 56 include polyethylene or polypropylene.
  • the truncated conical wall 60 is pointed toward the outlet end of the chamber 24 and guides the end of a cable 12 being threaded into the chamber 24 through the orifice 62.
  • the orifice 62 is generally of smaller diameter than the insulating sleeve 16.
  • the truncated conical wall 60 is of decreasing thickness toward the orifice 62 and will stretch adjacent the orifice 62 to closely surround the conductor element 21 and insulating sleeve 16 to provide a wiping action for restricting the grease 52 from moving with the cable 12 being threaded through the chamber 24.
  • grease 52 is retained within the chamber portion defined by the conducting member 28 and retaining member 56 to prevent air from entering the chamber 24 with the cable 12 and air pockets from developing upon movement of the grease.
  • the retaining member 58 has wall means comprising a hollow cylindrical wall 66 formed with axially extending grooves 68 on the outer periphery thereof, and a concentric hollow truncated conical wall 70 inwardly extending from an end 71 of the cylindrical wall 66 to an orifice 72 defined at the small end thereof.
  • the retaining member 58 is attached as by an adhesive to the insulator wall defining the cylindrical bore 44 within the predetermined distance from the inlet end 26 of the chamber 24.
  • the retaining member is attached at a point in the bore 44 at which the electrical stress is sufficiently small that air present in the chamber will not be sufficiently ionized and provide a wiping action for restricting grease from moving with the cable 12 through the chamber 24.
  • the grooves 68 provide a path for escape of grease 52 after engagement of the cable sleeve 16 with the orifice if further grease 52 is displaced as by increased volume of the entering section of cable 12.
  • -A cable 12 to be connected to the terminal 10 is prepared by attaching a connector element 21 to the conductor 14 and stripping the semi-conductive shield 18 from the end for a distance to expose an appropriate continuing length 20 of insulated conductor 14.
  • the plug 54 is removed from the terminal 10, and the cable 12 is threaded into the chamber 24 through the inlet end 26.
  • a terminal adapted for engagement with an end of a semiconductive shield for a high voltage electrical power cable having a central conductor, and an insulating sleeve between the conductor and the semiconductive shield, to afford connection of a continuing length of the insulated conductor to a second conductive member, said terminal comprising:
  • a boot having wall means for defining a bore with an inlet end and an opposite larger end, and having means adjacent the inlet end of said bore adapted for engagement with the end of the semiconductive shield to position the continuing length of the insulated conductor centrally projecting through the larger end of said bore;
  • an insulator having wall means for defining a cylindrical bore of larger diameter than said insulating sleeve and attached to the wall means of said boot adjacent said larger end with said bores aligned to centrally position a said continuing length of the insulated conductor within said cylindrical bore, said bores comprising a chamber within said terminal;
  • At least one retaining member having a hollow truncated conical wall mounted in said cylindrical bore within a predetermined distance from said inlet end with a large end thereof engaging the wall means of the chamber and a small end thereof directed away from said inlet end and adapted for engagement around the continuing length of the insulated conductor to retain said grease in said chamber about said continuing length of insulated conductor between said inlet end and said retaining member upon threading of the continuing length of insulated conductor through said chamber from said inlet end.
  • the terminal of claim 1 wherein said boot is a stress relief cone having a funnel-shaped bore, and said terminal comprises first and second retaining members, the large end of said first retaining member being mounted at the juncture between said stress cone and said insulator, and said second retaining member being spaced from said first retaining member along said cylindrical bore.
  • a terminal adapted for engagement with an end of a semiconductive shield for a high voltage electrical power cable having a central conductor, and an insulating sleeve between the conductor and the semiconductive shield, to afford connection of a continuing length of the insulated conductor to a second conductive member, said terminal comprising:
  • a stress relief member having wall means for defining a first bore with an inlet end and an opposite end, and having means adjacent the inlet end of said bore adapted for engagement with the end of the semiconductive' shield to position the continuing length of the insulated conductor centrally projecting through said opposite end of said first bore; an insulator having wall means for defining a cylindrical bore of larger diameter than said insulating sleeve and attached to the wall means of said stress relief member adjacent said opposite end with said bores aligned to centrally position a said continuing length of the insulated conductor within said cylindrical bore, said bores comprising a chamber within said terminal having an outlet opening spaced a first distance from said inlet opening;
  • a viscous electrically insulating grease filling a portion of said chamber extending from said inlet end, the volume of said insulating grease being only sufficient to fill the space within said chamber around the continuing length of the insulated conductor for a predetermined distance from said inlet end, said predetermined distance being less than said first distance;
  • At least one retaining member having a hollow truncated conical wall mounted in said cylindrical bore within said predetermined distance from said inlet end with a large end thereof engaging the wall means of the chamber and a small end thereof directed away from said inlet end and adapted for engagement around the continuing length of the insulated conductor to retain said grease in said chamber about the continuing length of insulated conductor between said inlet end and said retaining member upon threading of the continuing length of insulated conductor through said chamber from said inlet end.
  • terminal of claim 5 wherein said terminal comprises first and second retaining members, the large end of said first retaining member being mounted at the juncture between said stress relief member and said insulator, and said second retaining member being spaced from said first retaining member along said cylindrical bore.

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  • Cable Accessories (AREA)
  • Connector Housings Or Holding Contact Members (AREA)
US00185990A 1971-10-04 1971-10-04 Terminal with grease retaining members Expired - Lifetime US3730970A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US18599071A 1971-10-04 1971-10-04

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US3730970A true US3730970A (en) 1973-05-01

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US (1) US3730970A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
JP (1) JPS5512807B2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
AU (1) AU470616B2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
CA (1) CA989028A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
CH (1) CH544431A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
DE (1) DE2248963A1 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
GB (1) GB1401833A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)
ZA (1) ZA727058B (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3937870A (en) * 1974-08-08 1976-02-10 Clemar Manufacturing Corporation Device for insulating an electrical wire joint
US4204083A (en) * 1976-11-18 1980-05-20 Angelo Mariani Termination on electric power cables for normal, high and very high voltages
US4491686A (en) * 1982-12-21 1985-01-01 Imperial Underground Sprinkler Co. Electrical connector
US4714800A (en) * 1983-12-13 1987-12-22 Raychem Corporation Stress control/insulating composite article with an outer surface having convolutions and electric power cable terminated therewith
US20090153286A1 (en) * 2007-12-14 2009-06-18 Maclean-Fogg Company Insulator for cutout switch and fuse assembly
US9214318B1 (en) 2014-07-25 2015-12-15 International Business Machines Corporation Electromagnetic electron reflector

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5963912U (ja) * 1982-10-22 1984-04-27 岩崎電気株式会社 照明器具のア−ス掛止構造
JPH0197378A (ja) * 1987-10-08 1989-04-14 Tokyo Electric Co Ltd 端子装置
US5806111A (en) 1996-04-12 1998-09-15 Hill-Rom, Inc. Stretcher controls
US6330926B1 (en) 1999-09-15 2001-12-18 Hill-Rom Services, Inc. Stretcher having a motorized wheel
AU2001259732A1 (en) 2000-05-11 2001-11-20 Hill-Rom Services, Inc. Motorized propulsion system for a bed
US9707143B2 (en) 2012-08-11 2017-07-18 Hill-Rom Services, Inc. Person support apparatus power drive system
CN103074690A (zh) * 2013-02-26 2013-05-01 长沙丝美乐蚕业科技有限责任公司 一种煮茧用的可循环太阳能供水设备
US10912685B2 (en) 2015-07-24 2021-02-09 Stryker Corporation System and method of braking for a patient support apparatus

Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB262532A (en) * 1925-09-16 1926-12-16 Frederick Alexander Ross Bushes, glands, and the like for protecting, sealing, and bonding of electric cablesand the like
US2946839A (en) * 1959-02-24 1960-07-26 William A Horning Sleeve type joint protector
FR73501E (fr) * 1956-06-20 1961-01-09 Embouchoir pour câbles électriques ou autres canalisations
FI32282A (fi) * 1957-06-21 1962-01-10 Kaapelitiiviste
US3044037A (en) * 1960-05-27 1962-07-10 Herbert G Honig High voltage disconnect splice head
US3065292A (en) * 1958-05-22 1962-11-20 Burndy Corp Electrical connector
US3281524A (en) * 1964-04-03 1966-10-25 Thomas & Betts Corp Insulated service splicer assembly
US3322883A (en) * 1966-05-03 1967-05-30 G & W Electric Speciality Co Prefilled cable termination system
US3445580A (en) * 1967-10-13 1969-05-20 G & W Electric Speciality Co Power cable termination with improved entrance system
US3518358A (en) * 1967-06-19 1970-06-30 Dexter Corp Cable or like enclosure
US3542942A (en) * 1969-09-25 1970-11-24 Minnesota Mining & Mfg High voltage cable termination
US3548070A (en) * 1969-05-06 1970-12-15 Chance Co Ab Pothead with pressurized dielectric

Patent Citations (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB262532A (en) * 1925-09-16 1926-12-16 Frederick Alexander Ross Bushes, glands, and the like for protecting, sealing, and bonding of electric cablesand the like
FR73501E (fr) * 1956-06-20 1961-01-09 Embouchoir pour câbles électriques ou autres canalisations
FI32282A (fi) * 1957-06-21 1962-01-10 Kaapelitiiviste
US3065292A (en) * 1958-05-22 1962-11-20 Burndy Corp Electrical connector
US2946839A (en) * 1959-02-24 1960-07-26 William A Horning Sleeve type joint protector
US3044037A (en) * 1960-05-27 1962-07-10 Herbert G Honig High voltage disconnect splice head
US3281524A (en) * 1964-04-03 1966-10-25 Thomas & Betts Corp Insulated service splicer assembly
US3322883A (en) * 1966-05-03 1967-05-30 G & W Electric Speciality Co Prefilled cable termination system
US3518358A (en) * 1967-06-19 1970-06-30 Dexter Corp Cable or like enclosure
US3445580A (en) * 1967-10-13 1969-05-20 G & W Electric Speciality Co Power cable termination with improved entrance system
US3548070A (en) * 1969-05-06 1970-12-15 Chance Co Ab Pothead with pressurized dielectric
US3542942A (en) * 1969-09-25 1970-11-24 Minnesota Mining & Mfg High voltage cable termination

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Waddon, The Post Office Electrical Engineering Journal, Vol. 50 No. 4, Jan. 1958. Pages 219 221 *

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3937870A (en) * 1974-08-08 1976-02-10 Clemar Manufacturing Corporation Device for insulating an electrical wire joint
US4204083A (en) * 1976-11-18 1980-05-20 Angelo Mariani Termination on electric power cables for normal, high and very high voltages
US4491686A (en) * 1982-12-21 1985-01-01 Imperial Underground Sprinkler Co. Electrical connector
US4714800A (en) * 1983-12-13 1987-12-22 Raychem Corporation Stress control/insulating composite article with an outer surface having convolutions and electric power cable terminated therewith
US20090153286A1 (en) * 2007-12-14 2009-06-18 Maclean-Fogg Company Insulator for cutout switch and fuse assembly
US7646282B2 (en) 2007-12-14 2010-01-12 Jiri Pazdirek Insulator for cutout switch and fuse assembly
US20100102919A1 (en) * 2007-12-14 2010-04-29 Jiri Pazdirek Insulator for Cutout Switch and Fuse Assembly
US9214318B1 (en) 2014-07-25 2015-12-15 International Business Machines Corporation Electromagnetic electron reflector

Also Published As

Publication number Publication date
CH544431A (de) 1973-11-15
ZA727058B (en) 1973-06-27
JPS5512807B2 (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1980-04-04
DE2248963A1 (de) 1973-04-12
AU470616B2 (en) 1976-03-25
JPS4844793A (GUID-C5D7CC26-194C-43D0-91A1-9AE8C70A9BFF.html) 1973-06-27
AU4732172A (en) 1974-04-11
GB1401833A (en) 1975-07-30
CA989028A (en) 1976-05-11

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