Electricity: conductors and insulators – Conduits – cables or conductors – Single duct conduits
Reexamination Certificate
1999-06-10
2001-01-23
Kincaid, Kristine (Department: 2831)
Electricity: conductors and insulators
Conduits, cables or conductors
Single duct conduits
C174S15300A, C174S068300
Reexamination Certificate
active
06177633
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to electrical cable clamps, and more specifically to electrical connector clamps including a back-out prevention feature for securing electrical cables to wiring enclosures.
BACKGROUND OF THE INVENTION
The wiring of electrical devices requires that electrical cables be inserted through openings or holes in junction boxes, panel boxes and the like. Electrical codes generally require that such access holes be substantially filed after insertion of electrical cable and the some means be provided to inhibit retraction of the electrical cable from the access hole after installation to eliminate the possibility of accidental disconnection of the electrical connections internal to the panel box, junction box, etc. The most commonly used connector to provide such utility until recently has been a two-part device that permitted passage of the cabling through a circular collar that passed through the access hole and provided means for securing the cabling inside the circular collar and a lock nut or other means for, in turn, securing the collar to the access hole. Such devices are unwieldy and sometimes difficult to install, especially when space is limited, because of the number of parts involved and the need to apply screw drivers and wrenches to attain proper and secure attachment.
More recently, unitary plastic, strain relief, cable connector clamps, that include a self-locking mechanism as well as a cable retention system have been developed and found broader application. This type of cable clamp or connector is essentially tubular with a slit along one side to enable the connector to be squeezed for insertion into the access hole in the panel box, junction box, etc. It then resiliently returns to its original shape and is provided with protruding ribs to lock it into the opening.
It is common practice to include in the tubular portion of such connectors, clamping elements that resiliently deflect as the cable is inserted, with the free end of the clamping element biased against the cable sheath so as to engage the sheath between the clamping element and the inner wall of the connector to thereby prevent the cable from being readily withdrawn from the connector.
One such device is described in U.S. Pat. No. 5,594,209 to Nattel et al issued Jan. 14, 1997. This patent suggests a connector, as just described, that includes an internal clamping element that has a clamping lip that is resiliently pressed against the cable to prevent its removal from the connector. The clamping lip is described as having a reduced thickness at its free end and including additional projections on the inner wall of the tubular housing, which additional projections have abutment faces perpendicular to the axis of the housing.
U.S. Pat. No. 4,970,350 to Harrington, issued Nov. 13, 1990 describes a similar such connector device comprising a housing having first and second open ends and an inner wall forming a channel extending through the housing for receiving a cable. A coupling means is mounted within the housing for urging the cable towards the inner wall and includes a flange, means for grippingly engaging the cable between the inner wall and the flange, and an elongated bracing pin for providing resistance to bending of the flange.
While both of the foregoing patented devices provide useful solutions to the stated problem of providing a simple to use cable connector, their design is not optimal since they rely largely on simple friction or the presence of a single sharp surface to inhibit “pullout” of the inserted cable. Although the devices described in the foregoing patents allege an ability to retain a wide range of cable diameters, the range of their utility is really quite limited because of their design.
A better arrangement would provide a serrated engagement surface for retaining the inserted cable. Such a design provides a more secure retention of the inserted cable. The use of such a serrated surface, if properly designed, has the additional benefit of being more readily adaptable to a larger variety of cable diameters without sacrificing cable retention capability. The manufacture of such a connector using conventional plastic molding techniques is, however, not simple and requires redesign of the connector to obtain the required serrated contact points at the proper location and with the proper orientation in such a process.
Also, prior art such clamping or connector devices provide no means for releasing the retained cable without removing the entire connector assembly from its mounting in the junction box.
OBJECTS OF THE INVENTION
It is therefore an object of the present invention to provide a simple and easily installed connector for the attachment of electrical cabling to electrical panel boxes, junction boxes and the like that has the ability to securely retain a broad range of cable sizes and diameters while permitting release of the retained cable without removal of the connector from the junction box.
It is another object of the present invention to provide such a connector that is easily manufactured using conventional plastic molding techniques.
SUMMARY OF THE INVENTION
The connector clamp of the present invention is integrally molded from a resilient plastic material and comprises a cylindrical housing defining a passage for a cable and a slot in its outer perimeter that permits its compression and insertion into the knockout hole of an electrical junction box. Within the housing there is a resiliently deflectable retaining element having serrations or teeth running perpendicular to the axis of the cylinder for retaining an inserted cable. Through the wall of the cylinder at a point facing the serrations there is an aperture in the cylinder wall that permits access to the retaining element for purposes of releasing same from engagement with the inserted cable, assuming the size of the cable permits proper access. This aperture also serves as an access point for insertion of a core used in molding the serrations at the optimum angle perpendicular to the cylinder axis without significantly modifying the molding process.
REFERENCES:
patent: 3873759 (1975-03-01), Schindler et al.
patent: 4591658 (1986-05-01), Bauer et al.
patent: 4970350 (1990-11-01), Harrington
patent: 4972044 (1990-11-01), Kropa
patent: 5037318 (1991-08-01), Robertson
patent: 5132493 (1992-07-01), Sheehan
patent: 5539152 (1996-07-01), Gretz
patent: 5594209 (1997-01-01), Nattel et al.
Arlington Industries Inc.
Estrada Angel R.
Kincaid Kristine
LandOfFree
Cable connector does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Cable connector, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cable connector will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2463637