US3397308A

US3397308A - Lighting fixture

Info

Publication number: US3397308A
Application number: US587724A
Authority: US
Inventors: George P Wakefield; Harvey H Vick; Buckner Ned
Original assignee: Deutsche ITT Industries GmbH
Current assignee: Thomas and Betts Holdings Inc
Priority date: 1966-10-19
Filing date: 1966-10-19
Publication date: 1968-08-13
Anticipated expiration: 1985-08-13

Description

13, 1968 e. P. WAKEFIELD ET AL 3,3 7,308

LIGHTING FIXTURE 3 Sheets-Sheet 1 Filed Oct. 19, 1966 INVENTORS w E F K "M WV PH. V! 5 RV mm 6H e m \mm NED BUCK/V5 flMWMy fiamully ATTORNEYS Aug. 3, 1968 G. P. WAKEFIELD ET AL. 3,397,308

LIGHTING FIXTURE Filed Oct. 19, 1966 3 Sheets-Sheet 2 GEORGE WAKEFIELD 5.: HARVEY H. V/CK J 7 NED BUG/(IVER BY ()mmgfiwmdly ATTORNEYS j INVENTORS 3, 1968 G. P. WAKEFIELD ET AL 3,397,308

LIGHTING FIXTURE Filed Oct. 19, 1966 3 Sheets-Sheet 3 ENTORS INV GEORGE R WAKEFIELD HARVEY H. V/CK NED BUG/(IVER BY ammflmwi y ATTORNEYS United States Patent 3,397,308 LIGHTING FIXTURE George P. Wakefield, Harvey H. Vick, and Ned Buckner, Vermilion, Ohio, assignors to International Telephone and Telegraph Corporation, New York, N.Y., a corporation of Maryland Filed Oct. 19, 1966, Ser. No. 587,724 7 Claims. (Cl. 240128) ABSTRACT OF THE DISCLOSURE A lighting fixture having a housing with downwardly, outwardly sloping side walls for mating engagement by upper complementary tapered sides of a refractor. Refractor retaining latches on the housing yieldably urge the upper tapered sides of the refractor into firm seating engagement with the downwardly tapered sides of the housing.

The present invention relates generally, as indicated, to a lighting fixture and, more particularly, to certain improvements in lighting fixtures and especially the manner of attachment of refractors to the housings of such fixtures.

The use of refractor retainers in the form of spring clips and spring actuated latches for releasably securing refractors to lighting fixture housings is old and wellknown. However, it has been the usual practice when incorporating such spring clips and spring actuated latches as refractor retainers to provide the refractors with a metal frame or the like for engagement by the retainers, which substantially adds to the over-all cost of the fixtures. Moreover, a considerable portion of the refractor frames is often visible, thereby creating shadows and generally uneven lighting.

It is therefore a principal object of this invention to provide a lighting fixture with novel refractor retaining means for directly engaging the refractor, whereby the need for a refractor frame is eliminated.

Another object is to provide such a lighting fixture with retaining springs or spring actuated latches which cooperate with the fixture housing in a novel manner to lift the refractor and hold it in engagement with the fixture housing.

Yet another object is to provide such a lighting fixture with tapered outer surfaces adjacent the upper edge of the refractor which are urged into engagement with complementary tapered surfaces on the fixture housing through the lifting action of the refractor retainers.

A further object is to provide such a lighting fixture with retaining springs having lower cam surfaces which are adapted to be engaged by the upper edge of the refractor during assembly of the refractor to the housing for camming of the retaining springs out of the way.

A still further object is to provide such a lighting fixture with retainer latches and actuating springs for the latches which are adapted to be moved between a first latching position urging the latches into lifting engagement with the refractor and a second position holding the latches in an inoperative position for unobstructed removal of the refractor.

Another object is to provide such a lighting fixture in which the retainer latches are provided with lever arms which are adapted to be engaged by the refractor during assembly of the refractor and housing to cause movement of the latches from the inoperative position to the latching position.

Another object is to provide such a lighting fixture in which the sides of the refractor extend outwardly below the fixture housing to conceal the housing and end caps 3,397,308 Patented Aug. 13, 1968 ice so as to provide more uniform brightness and eliminate shadows.

A further object is to provide a fixture of the type described which may be mounted on a stem for spacing the fixture from the mounting surface, secured flush against the mounting surface, or recess mounted.

Other objects and advantages of the present invention will become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, the invention, then, comprises the features hereinafter fully described and particularly pointed out in the claims, the following description and the annexed drawing setting forth in detail certain illustrative embodiments of the invention, these being indicative, however, of but a few of the various ways in which the principles of the invention may be employed.

In such annexed drawing:

FIG. 1 is a transverse vertical section through a preferred form of lighting fixture constructed in accordance with this invention;

FIG. 2 is a fragmentary longitudinal section taken on the plane of the line 22 of FIG. 1 showing the manner of mounting the ballast to the fixture housing, with portions of the housing and ballast cover removed adjacent the ends of the fixture to show the manner of attachment of the end caps and lamp holders to the housing;

FIG. 3 is an enlarged fragmentary section taken on the plane of the line 33 of FIG. 1 illustrating how the refractor retaining springs are secured to the fixture hous- FIGS. 47 are schematic diagrams illustrating the manner in which the refractor may be disassembled from and assembled to the fixture housing;

FIG. 8 is an enlarged fragmentary section similar to FIG. 3, but illustrating another form of refractor retainer in accordance with this invention;

FIG. 9 is an enlarged fragmentary transverse section of still another preferred form of refractor retainer in accordance with this invention;

FIG. 10 is a fragmentary longitudinal section showing the refractor retainer of FIG. 9 in front elevation as seen from the plane of the line ill-1h; and

FIGS. 11 and 12 are schematic diagrams showing the various movements of the refractor retainers of FIGS. 9 and 10 during assembly and disassembly of the refractor to and from the fixture housing.

Referring now in detail to the drawing and first especially to FIGS. 1 and 2, a preferred form of lighting fixture shown by way of example is generally indicated at 1 and comprises a housing 2 of sheet metal or the like with end caps 3 riveted or otherwise attached to the ends thereof for supporting lamp holders 4 which are adapted to receive the terminals of fluorescent or like lamps 5. Although the number and disposition of the lamps 5 within the housing 2 may obviously be varied as desired, two such lamps are shown, one adjacent each side 6 of the housing. The lamp holders 4 are preferably suspended from the housing 2 by brackets 7 secured to the housing 2 as by means of suitable fasteners 8.

Centrally of the housing 2 there is provided a downwardly opening channel 10 formed by a pair of upwardly opening grooves 11 in the top wall 12 of the housing 2. Within the channel 10 there is disposed a ballast 15 for the lighting fixture 1, secured in place as by a tongue 16 struck down from the web 17 of the channel- 10 for receipt of a flange 18 at one end of the ballast 15 and a nut and screw assembly 19 attaching a flange 20 at the other end of the ballast 15 to the web 17. A ballast cover 21 encloses the open side of the channel 10 and is provided with V-shaped sides 22 which reflect the light emanating from the lamps 5. Horizontal flanges 23 extend from the upper 3 edges of the sides 22 for supporting the cover 21 by tongues 24 struck down from the bottom portions 25 of the grooves 11.

Secured to the bottom of the housing 2 there is a light refractor 30, which may be made of glass or any suitable plastic material such as acrylic or styrene plastic. The upper side edges 31 of the refractor are preferably tapered inwardly for seating engagement against the complementary outwardly tapered sides 6 of the housing 2, and a head 32 having a substantially vertical inner surface 33 and a horizontal lower shoulder portion 34 is formed on the upper side edges 31 for engagement by a plurality of spring type refractor retainers 35. The refractor retaining springs 35 may either be made from spring wire 36 bent into U-shape such as illustrated in FIGS. 17 or thin gauge spring steel sheet metal strips 37 such as illustrated in FIG. 8.

When spring wire 36 is used, the springs 35 are preferably attached to the underside of the housing wall 12 by positioning the ends 38 of the wire 36 between a U- shaped support plate 39 and wall 12 with a spacer 40 disposed between the wire ends 38, and riveting the support plate 39 and spacer 40 to the wall 12, as clearly shown in FIG. 3. When sheet metal strips 37 are used, the springs 35 may be riveted directly to the wall 12. (see FIG. 8).

In any event, the

retaining springs

35 or 35 are desirably bent in such a manner that their upper ends 42 conform to the configuration of the corner between the top and

side Walls

12 and 6, respectively. The central portion 43 of the retaining springs from just above the upper side edges 31 of the refractor 30, on the other hand, is bent downwardly in a substantially vertical direction out of contact with the side walls 6, with a hook portion 44 on the central portion adjacent the bead shoulder 34 which is adapted to underlie such shoulder for urging the upper side edges 31 of the refractor 30 upwardly into firm seating engagement with the complementary side walls 6 of the housing 2. Outwardly turned flanges 45 on the lower extremities of the side walls 6 limit the amount of upward movement of the refractor 30 by engagement with horizontal portions 46 of such refractor.

When it is desired to remove the refractor 30 from the housing 2 for re-lamping or other purpose such as cleaning the inside of the refractor, it is only necessary to grasp the horizontal portions 46 of the refractor and pull downwardly to cause springing in or the retaining springs 35 until the beads 32 clear the hook portions 44 (see FIGS. 5 and 6). Although not shown, a plastic retaining strip or the like may interconnect the refractor 30 and housing 2 to permit the refractor to hang from the housing in the disassembled position.

To facilitate reassembly of the refractor 30 to the housing 2, the lower ends 47 of the retaining springs 35 are bent downwardly and inwardly away from the side walls 6 so as to provide a cam surface for the upper side edges 31 of the refractor 30. Thus when the upper side edges 31 are raised into engagement with the lower spring ends 47, the spring ends are forced inwardly as shown in FIG. 7 until the beads 32 clear the hook portions 44, after which the refractor 30 may be readily pushed into position, aided by the action of the springs 35 tending to lift the beads 32 toward the side walls 6.

Another form of refractor retainer 50 in accordance with this invention is shown in FIGS. 9-12 and consists of a latch 51 pivotally mounted on a bracket 52 adjacent the lower inner edge 53 of the fixture housing 2 for swinging movement of the latch arm 54 into and out of engagement with the underside of the refractor portion 46. The bracket 52 may be secured to the fixture housing 2' as by means of a rivet 55 or other suitable fastener, and has a bent end portion 56 to which one end of a spring 57 is attached. The other end of the spring 57 is attached to a similar bent portion 58 on the latch 51 which bent portion 58 is radially spaced from the latch pivot 59.

When the refractor 30 is in the assembled position with 4 the latch arm 54 engaging the horizontal portion 46' of the refractor 30', the spring 57 will maintain the latch 51 in the latching position illustrated in FIGS. 9 and 10 yieldably urging the upwardly and inwardly tapered side edges 60 of the refractor 30 into firm seating engagement with the complementary tapered sides 6' of the fixture housing 2. However, should the refractor 30 be pulled downwardly to remove the refractor 30 from the fixture housing 2' for charging the lamps 5 and the like, the latch 51 will be pivoted by engagement of the housing portion 46' with the latch arm 54 to the over-center position of FIG. 12 whereat the spring 57 urges the latch 51 to an inoperative position clear of the refractor 30. A stop surface 61 on the latch 51 limits the movement of the latch away from the latching position by engagement with the side 6' of the fixture housing 2'.

The latch 51 will be retained in this inoperative position by the spring 57 until the latch is again pivoted toward the latching position of FIGS. 9 and 10 as by engagement of the tapered side edge 60 of the refractor 30 with an upper camming surface 65 on the latch 51 during reassembly of the refractor 30' in the fixture housing 2 (see FIG. 12). As soon as the latch 51 has swung far enough for its axis to cross back over the latch pivot 59, the spring 57 will continue the movement of the latch 51 toward its latching position and thus aid in lifting the refractor 30 into its assembled position in engagement with the lower portion of the fixture housing 2 as aforesaid.

Although the number of

refractor retainers

35 or 50 used in securing the

refractors

30 or 30 in place may obviously be varied as desired, it is preferred that four such retainers be provided, two for each side of the refractors. Moreover, the refractor sides 66 and 66 desirably extend outwardly beyond the housing sides 6 and 6', and the end caps 3 and 3' stop short of the

horizontal refractor portions

46 and 46, whereby there is a substantially uniform brightness at the sides as well as the ends of the refractors.

The lamp holders 4 are preferably contained within the

housings

2 and 2 itself to eliminate shadows which would otherwise be created thereby. Furthermore, although not shown, openings may be provided in the

refractors

30 and 30 to assist in cooling of the lamps 5 and ballast 15 and other openings may be provided in the top wall 12 to create a draft effect.

Other modes of applying the principles of the invention may be employed, change being made as regards the details described, provided the features stated in any of the following claims or the equivalent of such be employed.

We therefore, particularly point out and distinctly claim as our invention:

1. In a lighting fixture, a housing having a top wall and downwardly, outwardly tapering sides, a refractor having upper complementary tapered sides for mating engagement with the tapered sides of said housing, an integral shoulder formed on the inner surface of said refractor sides, and refractor retaining means comprising a plurality of spring means attached to said housing and provided with hook portions adapted to engage said shoulder on said refractor for yieldably urging said upper tapered sides of said refractor into firm seating engagement with said downwardly tapered sides of said housing, said spring means being made of spring wire having a generally U-shape in front elevation and secured to said top wall by a U-shaped support plate attached to said top wall with the ends of said spring Wire inserted between said top wall and support plate, and a spacer disposed between said wire ends, said spring means being provided with upper portions which are bent to conform to the corners defined between said top wall and sides of said housing, and central portions which are bent inwardly away from said housing sides slightly above said upper sides of said refractor, said hook portions being formed on the lower ends of said central portions.

2. In a lighting fixture, a housing having a top wall and downwardly, outwardly tapering sides, a refractor having upper complementary tapered sides for mating engagement with the tapered sides of said housing, and refractor retaining means attached to said housing and adapted to engage portions of said refractor for yieldably urging said upper tapered sides of said refractor into firm seating engagement with said downwardly tapered sides of said housing, said refractor retaining means comprising a plurality of latches, means pivotally mounting said latches interiorly of said housing, said latches having a latch arm which is adapted to be moved into and out of engagement with said refractor through pivotal movement of said latches, and spring means yieldably maintaining said latches in a latching position in contact with said refractor for yieldably urging said refractor into seating engagement with said housing as aforesaid, said spring means being attached to said latches radially spaced from their pivotal mountings for yieldably urging said latches to an inoperative over-center position whereat said latch arms are clear of said refractor in response to withdrawal of said refractor from said housing, said latches being provided with a stop surface which is adapted to engage the sides of said housing for locating said latches in such over-center position, and a camming surface which is adapted to be engaged by said refractor when said latches are in such over-center position for causing return movement of said latches to the latching position during insertion of said refractor within said housing.

3. The lighting fixture of claim 2 wherein said housing sides taper downwardly and outwardly from said top wall for their full length, and said tapered sides of said refractor have mating engagement with a substantial length of the tapered sides of said housing.

4. In a lighting fixture, a housing having a top Wall and downwardly, outwardly tapering sides, a refractor having upper complementary tapered sides for mating engagement with the tapered sides of said housing, and refractor retaining means attached to said housing and adapted to engage portions of said refractor for yieldably urging said upper tapered sides of said refractor into firm seating engagement with said downwardly tapered sides of said housing, said refractor sides having an integral shoulder formed on the inner surface thereof, and said refractor retaining means comprising a plurality of spring means attached to said housing and provided with hook portions adapted to engage said shoulder for releasably securing said refractor to said housing, said upper sides of said refractor having inwardly facing straight vertical portions extending upwardly from said integral shoulder, and said spring means having straight vertical portions which are adapted to engage said straight vertical portions of said upper sides of said refractor.

5. The lighting fixture of claim 4 wherein said refractor is provided with horizontal portions below said upper sides of said refractor which extend outwardly beyond said housing sides to conceal the same and provide a stop for limiting the upward movement of said refractor into said housing, and lamp holders are confined within said housing so as to provide substantially uniform brightness at the sides of said refractor which extend outwardly beyond said housing sides and eliminates shadows.

6. The lighting fixture of claim 4 wherein said housing sides taper downwardly and outwardly from said top wall for their full length, and said tapered sides of said refractor having mating engagement with a substantial length of the tapered sides of said housing.

7. The lighting fixture of claim 6 wherein said spring means have upper ends securely fastened to said top wall and adjacent portions bent to con-form to the corners defined between said top wall and tapered sides of said housing, and central portions bent at an acute angle inwardly away from said housing sides slightly above said upper sides of said refractor, said hook portions being formed on the lower ends of said central portions.

References Cited UNITED STATES PATENTS 2,887,569 5/1959 Frei 240128 3,043,951 7/1962 Tillson et al 240S1.11 3,248,534 4/1966 Cahill et al. 240128 FOREIGN PATENTS 369,209 6/ 1963 Switzerland. 194,635 2/ 1965 Sweden.

NORTON ANSI-1BR, Primary Examiner.

W. A. SIVERTSON, Assistant Examiner.