Thermally Protected Lamp Holder Housing for Use in Recess Lighting Fixtures

This invention relates to lamp holder housings. More particularly, this invention relates to lamp holder housings for use in recessed lighting fixtures and, in still greater particularity, this invention relates to a lamp holder housing including an arrangement for mounting both flexible conduit to the lamp holder housing and a thermal protective device within the interior of the lamp holder housing.

Heretofore, electrical conduit has been mounted to enclosures such as lamp holder housings with multi-piece connectors such as threaded male and female members specifically adapted to be inserted and retained within an access opening in the enclosure or housing. These connectors are typically provided with mechanical means for attachment to the conduit. Such mechanical means typically include hardware such as set screws, saddle type clamps and friction or compression type systems all configured for grasping the exterior of the conduit.

It has also been a practice in the field to provide protection against overheating for the surrounding structure. This protection is normally accomplished by including thermal sensors and switch assemblies within the lamp holder housing or adjacent to its exterior. These thermal sensors and switches open the electrical circuit which provides power to the lamp when excessive heat is detected. One of the most desirable locations for sensing heat is between the light source and the closed end of the housing. It is in this area that heat builds up and causes a potential hazard. Heretofore, special access holes, mounting brackets or hardware for securing the thermal protective device within the housing have been required to obtain this most desirable positioning of the thermal sensor.

The present invention provides a lamp holder housing having a simplified arrangement for mounting both an electrical conduit to the housing and a thermal protective device within the interior of the housing.

According to an important aspect of the invention, the lamp holder housing itself is provided with an access opening and a flange projecting from its sidewall configured to receive one end of a flexible electrical conduit. The flange defines one portion of a clamp for securing the conduit to the lamp holder housing.

There is also provided a bracket member adapted to both fit within the access opening and interact with the flange to define the second portion of the aforementioned clamp. Specifically, the bracket member has one leg configured to be compatible with the flange to engage an end of the flexible conduit and a second leg which extends into the interior of the housing in a spaced apart relationship with the inner surface of the housing sidewall. Provided on the second leg of the bracket is a mounting for a thermal protective device configured to place the thermal protective device in close proximity to the housing sidewall.

The invention further provides for a spring clip adapted to be received in a cut-out portion of the bracket member. The spring clip engages the thermal protective device to removably mount the protective device to the bracket member.

According to another important feature of the invention, the bracket member is shaped like an upside-down L to define an elongated, raised, flange-like portion at the junction of its horizontal and vertical legs. The raised portion abuts an edge of the access opening the closed end of the housing.

A still further important feature of the invention provides for a shoulder on the bracket member defined by the raised, flange-like portion and vertical leg of the bracket member. The shoulder is received against an inner surface of the closed end of the housing.

A still further important feature of the invention provides for a pair of raised projections on the flange and horizontal leg of the bracket member which are oriented and sized to threadably receive the external thread configuration of a BX type flexible conduit.

Another feature of the invention provides for a threaded fastener for holding the bracket member to the flange to clamp the conduit between the flange and bracket.

These and other features of the invention will become better understood after a reading of the following detailed description of the preferred embodiment taken in conjunction with the drawings wherein:

FIG. 1 is a top plan view of a lamp holder housing embodying the teachings of the present invention;

FIG. 2 is a side elevational view looking from imaginary line 2--2 of FIG. 1;

FIG. 3 is an exploded perspective view of the device of the present invention showing details of construction;

FIG. 4 is a side elevational view in partial section looking from imaginary line 4--4 of FIG. 1.

FIG. 5 is a side view in partial section of the device of the present invention;

FIG. 6 is an exploded perspective view of an alternate embodiment of the device of the present invention;

FIG. 7 is a view similar to FIG. 4 of the embodiment shown in FIG. 6; and

FIG. 8 is a view similar to FIG. 5 of the embodiment shown in FIG. 6.

Shown in FIGS. 1 and 2 is lamp holder housing 10 including a generally cup-shaped body having peripheral sidewall 12, closed end 14 and an open end 15. An electrical socket 16 (FIG. 5) is mounted within interior 15 of housing 10 against interior surface 13 of closed end 14. Housing 10 is of the type generally used in a recessed lighting fixture, the specific structure and features of which do not constitute part of the present invention.

As shown in FIG. 3 the body of housing 10 is provided with access opening 18 in one portion 19 of peripheral sidewall 12. Opening 18 provides for access to the interior 15 of housing 10 by electrical power leads 20, 22 (FIG. 5). In the preferred embodiment of the invention, access hole 18 is located where sidewall 12 joins closed end 14. Access opening 18 may be either square or rectangular thus defining edge 26 on closed end 14 along one side of opening 18. The utility of edge 26 is discussed below.

Conduit mounting flange 28 defines the bottom of first portion of a clamp for mounting electrical conduit 31. Flange 28 is provided on sidewall 12 of housing 10 at the bottom of access opening 18. Flange 28 is further defined as being positioned opposite edge 26 across opening 18 and extending substantially perpendicular from the exterior of sidewall 12. Conduit mounting flange 28 includes a semi-circular-shaped mounting surface 30 which is sized to receive thereagainst one end of conduit 31. It is contemplated that a flexible BX-type conduit 31 will be attached to housing 10, therefore, a first diagonally oriented projection 32 may be provided on surface 30 of flange 28 against which conduit 31 is engaged. While diagonally oriented projection 32 is shown in the preferred embodiment it is not required for operation of the invention. Projection 32 is configured and oriented to be received within low portions 33 of thread 35 of BX-type conduit 31. In addition thread 35 cooperates with a similar second projection 34 provided on surface 39 of horizontal portion 36 of bracket member 38. Projections 32 and 34 cooperate to threadably receive conduit 31 between conduit mounting flange 28 and bracket member 38.

Bracket member 38, referred to above, is a stamped, one-piece, generally upside-down L-shaped member having a first or horizontal leg 36 defining the semicircular-shaped second surface 39 of the clamping mechanism for holding conduit 31. Second or vertical leg 40 of bracket member 38 further extends from first leg 36 into interior 15 of housing 10 and is positioned in a substantially parallel, spaced-apart relationship from inner surface 37 of sidewall 12. Second or vertical leg 40 is also configured to fit into opening 18 so that it engages closed end 14. Specifically, an enlongated flange-like raised portion 42 and a shoulder 44 are formed by bends in leg 40. Bracket 38 is positioned within access opening 18 such that first leg 36 is engaged against conduit 31 and also secured to conduit mounting flange 28 with threaded fastener 46. Raised portion 42 is received into that portion of opening 18 which extends into closed end 14. In this position shoulder 44 is in surface contact with surface 13 as shown in FIG. 5. The structure described retains and positions bracket member 38 with respect to housing 10 and also provides for fast and simple positioning and retention of conduit 31 to housing 10.

Referring to FIGS. 3 and 4, second leg 40 of bracket member 38 is provided with cut-out 48 on one end which is configured to receive barb portion 50 of U-shaped spring clip 52. Clip 52 includes first leg 54 which is positioned against outermost surfaces 53 of bracket leg 40. Barb portion 50 of clip 52 is received within cut-out 48 and second leg 56 of clip 52 is positioned to reset against thermal protective device 57. Clip 52 is resilient and thereby holds thermal protective device 57 against innermost surface 59 of bracket leg 40. Further retention of thermal protective device 57 is provided by bent end portion 61 of second leg 56.

An alternative design of bracket member 38a is shown in FIGS. 6-8 wherein second leg 40a of bracket member 38a is elongated. Parts having the same function and relative location as in the preferred embodiment have been identified with the suffix "a". Spring clip 52a is positioned such that first leg 54a of clip 52a holds thermal protective device 57 in the same manner as described in connection with the embodiment shown in FIG. 3 except thermal protection device 57 is positioned on the outside of bracket member 38a.

In FIGS. 3-5 thermal protective device 57 is positioned transverse to the longitudinal axis of socket 16, while in the embodiment of FIGS. 5-7, thermal protective device 57 is oriented generally parallel to the longitudinal axis of socket 16. In either case, thermal protective device 57 is electrically coupled in series with lamp socket 16 and will cause the electrical circuit to open when a predetermined level of heat is sensed.

A lamp holder housing 10 constructed according to the principles of the present invention provides a simplified, cost effective structure for attaching an electrical conduit without the use of extraneous hardware. Additionally, the lamp holder housing 10 of this invention also provides for the mounting of a thermal protective device 57 within the interior of the housing 10 in close proximity to the housing sidewall 12 without the use of special access holes, mounting brackets or hardware.

Having now described the preferred embodiment of the invention, those skilled in the art having the benefit of the description and the accompanying drawings may readily devise other embodiments and modifications. Such other embodiments and modifications are to be considered within the scope of the appended claims.