Luminaire Attachment Device

The present invention relates to luminaires, and more particularly concerns luminaires of hazardous duty type having a globe and protective guard attached thereto.

It is an object of the invention to provide a luminaire of the above type having an improved attachment device for readily attaching and detaching the globe and protective guard without the use of tools.

Another object of the invention is to provide a simple attachment device of the above type which firmly holds the globe and protective guard in assembly with the luminaire and enables the assembly to withstand the effects of vibration and shock under operating conditions.

A further object of the invention is to provide an attachment device of the above type which does not hinder ready removal of the attached luminaire components for maintenance and replacement.

Other objects and advantages will become apparent from the following description and the appended claims.

With the above objects in view, the present invention in one of its aspects relates to a luminaire comprising, in combination, support means comprising a socket having a screw-threaded wall defining a socket bore open at one end, the wall having an opening extending transverse the threads thereof and having an end face at the open end, an elongated spring member having an intermediate mounting portion and opposite end portions, the spring member secured to the socket end face with one end portion received in the transverse wall opening and normally protruding therefrom into the socket bore, the opposite end portion of the spring member extending along the end face of the wall and formed with a transverse catch portion, a globe having an open top threadably engaging the screw-threaded socket wall and yieldably engaged by the protruding spring end portion for firmly holding the globe in removable assembly in the socket, and a cage-like guard having an open end secured to the support means and extending around the globe, the support means having inwardly directed flange means at the open end of the socket, the guard formed at its open end with a shoulder portion, the guard being rotatable in one direction relative to the support means with the shoulder portion engaging the flange means for moving the guard into attached position, the shoulder portion formed with detent means engaged by the spring catch portion for yieldably holding the guard in attached position on the support means, the guard being rotatable in the opposite direction for releasing the detent means thereof from the spring catch portion for removing the guard from the attached position.

The invention will be better understood from the following description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a view in elevation of a hazardous duty luminaire in which the invention may be embodied;

FIG. 2 is an exploded view of the FIG. 1 luminaire showing the luminaire globe and its guard spaced from their support socket on the upper luminaire housing;

FIG. 3 is a fragmentary perspective view in enlarged scale of the support socket showing the retaining device for the luminaire globe and guard in accordance with an embodiment of the invention;

FIG. 4 is a sectional view in somewhat enlarged scale of the socket structure shown in FIG. 3 taken along the line 4--4;

FIG. 5 is a plan view of the spring retaining device employed in the FIG. 3 embodiment;

FIG. 6 is a plan view in reduced scale of the spring retaining device in assembly on the support socket;

FIG. 7 is a bottom plan view in enlarged scale of a portion of the support socket showing portions of the globe and guard in assembly therewith;

FIG. 8 is a top plan view in enlarged scale of the globe guard shown in FIG. 2; and

FIG. 9 is a detail view in cross-section of a portion of the protective guard, taken along the line 9--9 of FIG. 8.

Referring now to the drawings, and particularly to FIGS. 1 and 2, there is shown a luminaire 1 of hazardous duty type comprising a ballast housing 2 having a collar 3 secured at the bottom thereof and forming a shallow support socket for receiving and removably holding transparent globe 4 and cage-like metal guard 5 surrounding the globe. Globe 4 encloses lamp 6, typically a high intensity gaseous discharge lamp, which is mounted at its upper (base) end in electric socket 7 within collar 3 and extends downwardly therefrom along a vertical axis about which globe 4 and protective guard 5 are substantially concentric. Ballast housing 2 contains electrical components (not shown) for operating discharge lamp 6.

As seen in FIG. 3, support socket 3 is formed with screw-threads 3a on its internal surface, and globe 4, which is typically made of glass, is formed adjacent its open upper end with external threads 4b, so that the globe may be screwed into housing socket 3 to install it in position around lamp 6. Socket 3 is formed at its bottom with circumferentially spaced flanges 3b projecting inwardly below bottom end face 3c of threaded socket wall 3d. Protective guard 5 is formed at its top edge with a pair of upwardly projecting arc-shaped shoulders 5a arranged diametrically opposite one another (see FIGS. 2 and 8). As seen in the cross-sectional view of FIG. 9, shoulders 5a are formed at their top with an outwardly projecting flange 5b. At their front ends, each shoulder 5a is formed with a tapered portion 5d and a recess 5e spaced rearwardly therefrom. In the assembly of guard 5 with the support socket 3, the guard is moved upward into socket 3 with its shoulders 5a inserted into entrance slots 3e between socket flanges 3b, as indicated by the interrupted lines in FIG. 7, and the guard is rotated clockwise as viewed in FIG. 7 with flanges 5b inserted in the space between socket flange 3b and the bottom end face 3c of threaded socket wall 3d, so that guard flange 5b rides on socket flange 3b during such rotation. Rear surface 5c of each shoulder 5a serves as a stop which prevents clockwise rotation of guard 5 by abutting the edge of socket flange 3 in the event of such rotation.

In accordance with the invention, a dual function wire spring 10 having the form shown in FIG. 5 is secured to the bottom end face 3c of socket wall 3d, the spring being constructed and arranged to firmly and resiliently hold both globe 4 and protective guard 5 in assembled position in housing socket 3. As seen in FIGS. 3 and 5, wire spring 10 has a substantially flat loop 10a formed in its intermediate portion, a V-shaped catch portion 10b at one end, and a bent bearing portion 10c at its other end (see FIG. 3) extending in a plane transverse the planes of loop portion 10a and catch portion 10b. As seen in FIG. 3, spring 10 is secured to socket wall 3d by a screw 11 or the like passing through spring loop 10a and screwed into socket end face 3c, with the spring end portion having catch 10b extending along end face 3c and the opposite end portion comprising bent member 10c partially inserted into slot 3e in threaded socket wall 3d so that the yieldable bearing member 10c projects outwardly from the slot, as seen best in FIG. 4. In a typical arrangement, a similar spring member (not shown) is mounted on socket wall 3d diametrically opposite the described spring member.

In the operation of the disclosed device, when globe 4 is screwed into socket 3, its upper threaded portion comes into contact with spring bearing member 10c, pushing the protruding portion of the latter partially into slot 3e. Bearing member 10c thereby exerts sufficient resilient pressure against the threaded portion of globe 4 to effectively prevent loosening of globe 4 from the support socket 3 due to vibration or other operating conditions, while still permitting the globe to be readily unscrewed for removal from the socket.

When protective guard 5 is inserted into socket 3 enclosing globe 4 and rotated clockwise as viewed in FIG. 7, as previously described, the tapered leading end 5d of each shoulder comes into contact with spring catch 10b of the respective springs and with continued rotation displaces and rides past the latter until catch 10b snaps into recess 5e of the shoulder. Recess 5e has a shape complementary to the shape of catch 10b, so that when the latter is seated in the recess, guard 5 is effectively held in assembled position and can withstand vibration and impact conditions encountered in typical installations without tending to rotate out of its assembled position. The arrangement is such, however, that guard 5 may be readily manually rotated counter-clockwise to disengage the recessed shoulders from the spring catches 10b for removal of the guard from the fixture.

There are thus provided by the invention means for readily and rapidly removing the globe and the protective guard of hazardous duty luminaires without the use of tools to allow relamping, cleaning of the globe, and other maintenance procedures, while providing secure attachment of these parts to the lighting fixture.

While the present invention has been described with reference to particular embodiments thereof, it will be understood that numerous modifications may be made by those skilled in the art without actually departing from the scope of the invention. Therefore, the appended claims are intended to cover all such equivalent variations as come within the true spirit and scope of the invention.