Classifications

• • 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
  • H02G3/00—Installations of electric cables or lines or protective tubing therefor in or on buildings, equivalent structures or vehicles
  • H02G3/02—Details
  • H02G3/06—Joints for connecting lengths of protective tubing or channels, to each other or to casings, e.g. to distribution boxes; Ensuring electrical continuity in the joint
  • H02G3/0616—Joints for connecting tubing to casing
  • H02G3/0625—Joints for connecting tubing to casing with means for preventing disengagement of conductors
  • H02G3/065—Joints for connecting tubing to casing with means for preventing disengagement of conductors with means biting into the conductor-insulation, e.g. teeth-like elements or gripping fingers
• • 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
  • H02G3/00—Installations of electric cables or lines or protective tubing therefor in or on buildings, equivalent structures or vehicles
  • H02G3/02—Details
  • H02G3/06—Joints for connecting lengths of protective tubing or channels, to each other or to casings, e.g. to distribution boxes; Ensuring electrical continuity in the joint
  • H02G3/0616—Joints for connecting tubing to casing
  • H02G3/0625—Joints for connecting tubing to casing with means for preventing disengagement of conductors
  • H02G3/0675—Joints for connecting tubing to casing with means for preventing disengagement of conductors with bolts operating in a direction parallel to the conductors

Definitions

• the present invention relates to a sealing and tension- -relieving -screw fitting intended for leading electric " cables through the casings of divers electrical appara ⁇ tus.
• the screw fitting which is of the so-called chuck kind, incorporates a sleeve having provided on one end part thereof a first external screw thread by means of which the screw fitting is attached to the apparatus casing or like component
• the screw fitting further in ⁇ corporates a barrel or gland nut which partially embra ⁇ ces the sleeve and which is screwed onto a second screw thread provided externally on the sleeve.
• the barrel or gland nut has provided internally thereof a funnel shaped part which lies in abutment with finger-like elements arranged on the other end of the sleeve, these finger- -like elements being pressed against and into gripping contact with a cable drawn through the screw fitting, when the gland nut is screwed onto the sleeve.
• a conventional and much used bushing is one which comprises a sleeve having provided on one end thereof an external screw thread by means of which the bushing can be attached to a casing or housing, and in which the other end of the sleeve accommodates internally a sleeve-like nut which is operative in pressing a rubber seal against a seating, this rubber seal being intended to be pressed against a cable drawn through the bushing, when the nut is screwed into the sleeve.
• the size of the cable coincides generally with the size of the hole pro ⁇ vided in the rubber seal, the seal will abut tightly against the cable in a sealing fashion, while at the same time relieving the tensile load on the cable to some extent.
• the nut is usually provided with an extension which co-acts with a locking means to this end, the cable being clamped firmly to the nut extension upon co-action of the nut with the locking means.
• bushing of this kind One drawback with bushing of this kind is that the seals used must be of the correct size, and that the nut must be screwed tight with the aid of a suitable tool, in order to obtain a satisfactory seal. In tightening the nut fully, it is possible that the position taken by the nut is such as to make it virtually impossible to mani ⁇ pulate the locking means . In addition in those cases where an apparatus casing or housing is fitted with a plurality of cable bushings, the bushings are normally located very close together, making it difficult and time- -consuming to fit a nut with the aid of a tool. This often results in inefficient sealing of the bushings. Bushings of the so-called chuck-type have also been developed.
• bushings comprise an outer barrel or gland nut which embraces the bushing sleeve and which is provided with an internal funnel-shaped part which abuts finger- -like elements extending axially from one end of the sleeve and surrounding a tubular rubber seal, this seal being pressed against a cable drawn through the bushing, when the barrel or gland nut is screwed onto the sleeve.
• Such bushings can only be used effectively with cables over a small range of diameters and, furthermore, the barrel or gland nut must be screwed very tight. in order to afford a satisfactory seal and to satisfactorily re ⁇ lieve the cable of tensile load.
• the object of the present invention is to provide a bush ⁇ ing which is not encumbered with the aforesaid drawbacks, i.e. a bushing with which the size of the seal need not be adapted to individual cables, but which will provide an effective seal in respect of cables lying within a wide range of diameters, irrespective of the extent to which the nut is tightened.
• a further object is to pro ⁇ vide a readily fitted screw fitting which can be tighte ⁇ ned by hand to the extent required, without needing to use a tool herefor.
• Figure 1 which is an axial sectional view of the bushing, the reference 1 identifies a sleeve having pro ⁇ vided on one end thereof an external screw-thread 2 , by means of which the bushing is screwed onto an apparatus casing or housing, not shown.
• the sleeve 1 is partially embraced by a barrel or gland nut 3 having an internal screw-thread 4 which engages a further screw-thread 5 provided externally on the sleeve 1.
• the barrel nut 3, the outer surface of which is serrated, includes an in ⁇ ternal, funnel-shaped part 6 which abuts against finger- -like elements 7 arranged in the other end part of the sleeve 1.
• a sealing sleeve 8 Located within the sleeve 1 is a sealing sleeve 8, or constric ⁇ ted nipple, which incorporates a funnel-shaped part 11 surrounded by a substantially cylindrical tubular part 9 which sealingly abuts against the inner surface of the sleeve and against a shoulder 10 provided on the sleeve wall.
• the finger-like elements 7 bend over the edge of the sealing sleeve 8, and press the sealing sleeve against the shoul ⁇ der 10, the sleeve thus lying against the shoulder under pressure.
• FIG. 2 is an exploded view of the bushing, are the same as those used in Figu- re 1 to identify similar components. It will be seen from Figure 2 that the bushing comprises a substantially hexagonal part 12, which facilitates the attachment of the bushing to the casing or housing of a piece of appa ⁇ ratus. Because the sealing function of the bushing has been se ⁇ parated from its tension-relieving function, and as a re ⁇ sult of the construction of the sealing sleeve and its locked positioning in the sleeve, a good seal will always be obtained between the cable and the bushing, irrespec ⁇ tive of whether the nut is tight or not.

Landscapes

• Engineering & Computer Science (AREA)
• Architecture (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Cable Accessories (AREA)
• Installation Of Indoor Wiring (AREA)
• Insulating Bodies (AREA)
• Bridges Or Land Bridges (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20357236

Family Applications (1)

Country Status (7)

Cited By (1)

Families Citing this family (8)

Family Cites Families (5)

• 1984
  • 1984-10-04 SE SE8404975A patent/SE463843B/sv not_active IP Right Cessation
• 1985
  • 1985-09-27 JP JP50451785A patent/JPS62500349A/ja active Pending
  • 1985-09-27 WO PCT/SE1985/000374 patent/WO1986002209A1/en active IP Right Grant
  • 1985-09-27 EP EP19850905123 patent/EP0196326A1/en not_active Withdrawn
• 1986
  • 1986-05-26 NO NO86862082A patent/NO169149C/no not_active IP Right Cessation
  • 1986-05-27 FI FI862228A patent/FI83375C/fi not_active IP Right Cessation
  • 1986-06-03 DK DK260486A patent/DK159702C/da not_active IP Right Cessation

Non-Patent Citations (1)

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