Electricity: conductors and insulators – Conduits – cables or conductors – Combined
Reexamination Certificate
1999-03-19
2001-07-10
Kincaid, Kristine (Department: 2831)
Electricity: conductors and insulators
Conduits, cables or conductors
Combined
C174S07400A
Reexamination Certificate
active
06259029
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to cable glands.
Cable glands for connecting an electric cable to a piece of equipment such as a junction box are known for use in hazardous environments to provide a sealed entry for the cable to contain any explosion occurring within the equipment.
The seal may be of the compression type in which relative rotation of two threadably engaged parts of the gland compresses the seal inwardly to bear onto the surface of the cable. This type of seal has to be matched to the size of the cable and use of the incorrect seal can result in poor sealing efficiency. In addition, the compression force can result in the surface of the cable becoming deformed with subsequent loss of sealing efficiency if the gland is taken apart for inspection and then re-assembled.
These problems are largely avoided by a diaphragm type of seal in which an opening in the seal adapts automatically to different sizes of cable. A cable gland with this type of universal seal is the subject matter of our granted UK Patent No. 2276777-B.
We have now found, however, that during assembly of such glands having a universal seal, the marginal edge of the opening in the seal can be damaged by contact with the sharp conductor cores and/or rough edges of the cut end of the cable sheath as it is pushed through the opening. Such damage reduces sealing efficiency and, in certain cases, the seal may not meet safety requirements requiring the seal to be replaced which is time consuming.
The same problem can arise but usually to a lesser extent with seals of the compression type. For this reason, it has been the practice, whichever type of seal is used, to cover the cut end of the cable with an adhesive tape to reduce the risk of damage to the seal. Often the glands are assembled in conditions of restricted space and/or visibility with the result that the taping of the cut end of the cable and subsequent removal of the tape is awkward and adds considerably to assembly time.
The present invention has been made from a consideration of the foregoing problems and disadvantages of known cable glands.
SUMMARY OF THE INVENTION
It is a primary object of the present invention to provide a cable gland in which damage to the seal(s) by the cut end of the cable is substantially avoided in a simple, effective manner without taping the cut end of the cable.
According to the present invention there is provided in or for a cable gland, a cap member for the cut end of a cable, the cap member being constructed and arranged to pass with the cable through a seal in the gland and thereafter to be removable from the cable.
As will be appreciated, the cap member facilitates passage of the cable through the seal and prevents the seal being damaged by the cut end of the cable in a simple, effective manner which avoids taping the cut end of the cable.
The seal may be of the universal type with the cap member being appropriately dimensioned for use with any selected one of a range of different cable sizes and types.
The cap member may be made of any material having the required flexibility and strength to pass with the cable through the seal without tearing. For example, the cap member may be made from appropriate plastics or paper materials.
The invention will now be described in more detail by way of example only with reference to the accompanying drawings.
REFERENCES:
patent: 2145705 (1939-01-01), Wodtke
patent: 4273405 (1981-06-01), Law
patent: 4515991 (1985-05-01), Hutchison
patent: 5059747 (1991-10-01), Bawa et al.
patent: 5310963 (1994-05-01), Kennelly
patent: 5589663 (1996-12-01), Wales
patent: 5621191 (1997-04-01), Norris et al.
patent: 5691505 (1997-11-01), Norris
patent: 5951327 (1999-09-01), Marik
patent: 2 691 852 (1993-12-01), None
patent: 2 276 777 (1996-10-01), None
patent: 05083823 (1993-08-01), None
Cantor & Colburn LLP
Hawke Cable Glands Limited
Kincaid Kristine
Mayo, III William H
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