Electrical connectors – Metallic connector or contact having movable or resilient... – Screw-thread operated securing part
Reexamination Certificate
2000-12-28
2001-08-28
Sircus, Brian (Department: 2839)
Electrical connectors
Metallic connector or contact having movable or resilient...
Screw-thread operated securing part
C335S202000
Reexamination Certificate
active
06280264
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a terminal connector for connecting wiring to switches used in electric power circuits, and particularly to such a terminal connector which can accommodate a wide range of wire sizes and alternate mounting configurations of the switches.
2. Background Information
Where electric power switches such as circuit breakers, transfer switches, contactors and the like are used in distribution systems having wires as the conductors, terminal connectors are needed to connect the wiring to the rigid, generally flat conductors of the switches. A common type of connector has a collar with a transverse slot engaging the flat conductor of the switch. An adjacent aperture receives the wire which is clamped against the flat conductor by a screw threaded into a longitudinal bore in the collar.
Depending upon the installation, or section of an installation, the size of the wire may vary over a wide range, e.g., from 14 AWG to 1/0. With wire at the lower end of the range of sizes, the installer must be careful to ensure that the wire is directly in line with the screw. Otherwise, a poor connection can result, such as where the smaller diameter wire lodges between the side of the screw and the edge of the aperture. Such a connection will not pass the required pull test in which the connection must support a designated weight for a prescribed time period.
For electric power switches with molded casings, the terminal connectors are typically disposed in pockets formed in the ends of the molded casing with the wires inserted laterally into the aperture in the terminal collar and with the screw accessible from the top face of the casing. Where the switches are mounted with the bottom face engaging rails, the screws are easily accessible for connecting and disconnecting the wiring. Currently, different terminal connectors are required when the switches are front mounted, that is, with the front face facing a panel so that the terminal screws are accessible from the bottom face of the switch. Otherwise, the switch cannot be wired while installed on the panel.
SUMMARY OF THE INVENTION
This invention is directed to an improved terminal connector and an electric power switch incorporating the improved terminal connector. The terminal connector, for use in connecting wire with a range of sizes to a flat conductor of an electric power switch, comprises a collar with a lateral slot sized and shaped for receiving the conductor of the switch. An aperture adjacent to and intersecting the slot is sized for receiving the full range of sizes of the wire. The collar also has a longitudinally extending tapped hole transverse to and intersecting the aperture. The terminal connector further includes a telescoping screw comprising an outer screw with an external thread threaded into the tapped hole of the collar and a tapped longitudinal bore. The telescoping screw also includes an inner screw threaded into the tapped longitudinal bore of the outer screw. The outer screw is advanced in the threaded hole in the collar to clamp the wire against the conductor of the switch with the inner screw being advanced toward the switch conductor beyond the outer screw when the wire is in the lower end of the range of diameters.
The aperture is shaped to cam the wire in the lower range of diameters into engagement with the flat conductor as the inner screw is advanced toward the flat conductor. Preferably, the aperture is at least partially circular, having a diameter complementary to that of the wire at the upper end of the range of diameters. More particularly, the aperture can have a circular section not intersecting the slot and a transition section extending between the circular section and the slot. This transition section can be a cylindrical passage axially aligned with the threaded bore in the collar and with a diameter complementary to the diameter of the inner screw. The inner screw may be provided with a beveled end extending toward the slot in the collar to form an annular gap with the cylindrical passage and the flat conductor having a cross section smaller than the diameter of the wire. The circular section of the aperture in the collar can be sized, for example, to receive a 1/0 wire at the upper end of the wire diameters and the annular gap can be sized smaller than a #14 wire at the lower end of the range of wire diameters. In addition, the collar can have a longitudinal hole extending to the slot and a fastener extending through this hole to secure the flat conductor in the slot of the collar.
The invention also embraces an electric power switch having a molded casing with a top face, a bottom face and an end face between the top and bottom faces with the end face having an elongated recess. A conductor of the switch projects from the molded case into the elongated recess. A reversible terminal for securing a wire to the switch conductor in the recess comprises a collar having a first aperture extending laterally in the collar and sized and shaped to receive the switch conductor. A second aperture extends laterally in the collar substantially parallel to and intersecting the first aperture. The first aperture is adjacent a first end of the collar through which a first axial bore extends to the first aperture. A first fastener extends through this first bore and engages the switch conductor to clamp the collar to the switch conductor. A second axial bore extends from the second end of the collar to the second aperture. A second fastener in the form of a screw threads into the second bore and clamps the wire inserted into the second aperture against the switch conductor to effect an electrical connection between the wire and the switch conductor. The collar and the recess in the molded housing are shaped for reversible mounting of the collar on the switch conductor with the second fastener selectively accessible through the recess from the top face of the molded casing and alternatively from the lower face. For installations where the wire can have a range of diameters, the screw can be the telescoping screw described above.
REFERENCES:
patent: 2777119 (1957-01-01), Edmunds
patent: 2885654 (1959-05-01), Norden
patent: 4457577 (1984-07-01), Browne et al.
patent: 4603376 (1986-07-01), Maier
patent: 5206789 (1993-04-01), Barbry
patent: 6084188 (2000-07-01), Mueller et al.
patent: 6211759 (2001-04-01), Little et al.
Lias Edward Ethber
Whipple Michael Jerome
Dinh P K
Eaton Corporation
Moran Martin J.
Sircus Brian
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