Twist lock fixture attachment system
AssigneeGeneral Electric Company
InventorLee J. Belknap
Life of this patent
Estimating the term…
Abstract
A twist lock attachment system for attaching a fixture having a sheet metal mounting plate that is part of a sheet metal housing to a structural support. The exemplary fixture disclosed is a lighting fixture attached to a wiring conduit. The mounting plate has a generally circular mounting aperture. A twist lock bushing includes a tubular body correspondingly generally circular in cross section. The mounting plate and the twist lock bushing releasably engage each other by relative movement to insert the tubular body into the mounting aperture with the mounting plate and the bushing angularly oriented in an insertion and removal position with reference to each other, followed by rotation of the mounting plate and the twist lock bushing relative to each other to an installed position.
Claims18
A twist lock attachment system comprising:
- a mounting plate made of sheet metal and included as part of a fixture, said mounting plate having an exterior surface and an opposed interior surface separated by a mounting plate thickness, and a generally circular mounting aperture;
- a twist lock bushing attachable to a structural support, said twist lock bushing including a tubular body generally circular in cross section having an insertion end and an opposite end;
- said mounting plate and said twist lock bushing releasably engaging each other by relative movement to insert said tubular body into said mounting aperture with said mounting plate and said bushing angularly oriented in an insertion and removal position with reference to each other, and subsequent rotation of said mounting plate and said twist lock bushing relative to each other in a first rotational direction to an installed position;
- said tubular body including
- a radially-extending top flange located intermediate said opposite end and said insertion end, said top flange having a flange bearing surface axially facing said insertion end for limiting relative axial movement in an insertion direction by bearing against said exterior surface of said mounting plate, said flange bearing surface defining a flange bearing surface plane, and
- at least two radially-extending locking tabs intermediate said top flange and said insertion end and generally adjacent said insertion end, said locking tabs having locking tab bearing surfaces axially facing said opposite end for retaining said tubular body within said installed position by bearing against said interior surface of said mounting plate in the installed position, said locking tab bearing surfaces being spaced from the flange bearing surface plane a distance corresponding to the thickness of said mounting plate;
- said mounting plate having at least two locking tab clearance slots extending radially from said mounting aperture for clearing said locking tabs as said tubular body is inserted into or removed from said mounting aperture in the insertion and removal position;
- said top flange having at least one flange set screw aperture and said mounting plate having at least one mounting plate set screw aperture, said flange set screw aperture and said mounting plate set screw aperture being angularly located with reference to each other so as to be in alignment in the installed position so that a set screw within said set screw apertures prevents relative rotational movement of said mounting plate and said bushing,
- wherein said at least one mounting plate set screw aperture comprises a further radial extension of at least one of said locking tab clearance slots;
- and
- releasable elements for preventing relative rotational movement of said mounting plate and said bushing in the installed position.
Dependencies are inferred from the claim text.