US3755666A

US3755666A - End cap construction

Info

Publication number: US3755666A
Application number: US00212231A
Authority: US
Inventors: J Edgeington
Original assignee: IMS Corp
Current assignee: IMS Corp
Priority date: 1971-12-27
Filing date: 1971-12-27
Publication date: 1973-08-28
Anticipated expiration: 1990-08-28

Abstract

An end cap structure comprises a housing portion formed of smooth sheet material having an open portion to be covered by an end cap. The end cap has a wall portion positioned over the opening and turned edges formed around the periphery of the cap in conformity with the outer configuration of the housing being covered. The housing has a deformable surface or covering, at least in the area receiving the end cap, and at least one protuberance is formed on the turned edges, at the inner side thereof, to come into pressing contact with the deformable covering on the housing. The protuberance will cause cold flow of the covering thereby forming a dimple under the protuberance to hold the cap to the housing.

Description

United States Patent [1 1 Edgeington, Jr.

[451 Aug. 28, 1973 END CAP CONSTRUCTION [75] Inventor: James NQEdgelngton, Jr.,

Albuquerque, N. Mex.

[73] Assignee: IMS Corporation, Albuquerque, N.

Mexl

[22] Filed: Dec. 27, 1971 [21] Appl. No.: 212,231

Bucek 240/51. R

An0rneyRoy H. Olson et a1.

[57] ABSTRACT An end cap structure comprises a housing portion formed of smooth sheet material having an open portion to be covered by an end cap. The end cap has a wall portion positioned over the opening and turned edges formed around the periphery of the cap in conformity with the outer configuration of the housing being covered. The housing has a deformable surface or covering, at least in the area receiving the end cap, and at least one protuberance is formed on the turned edges, at the inner side thereof, to come into pressing contact with the deformable covering on the housing. The protuberance will cause cold flow of the covering thereby forming a dimple under the protuberance to hold the cap to the housing.

8 Claims, 5 Drawing Figures PATENTED A08 28 1973 3. 7 55 666 END CAP CONSTRUCTION BACKGROUND OF THE INVENTION This invention relates generally to an end cap construction and more particularly to an end cap for use with plastic coated metal housings, or the like.

Heretofore, snap-on end caps for housing structures have been constructed by forming turned edge portions along the periphery of the end cap. The turned edge portions are either formed by bending the material or by stamping or extruding a blank in a die. Aligned holes are sometimes formed in the end cap and the housing to receive a screw or rivet to secure the end cap to the housing. However, this type of end cap configuration requires accurate alignment of the holes. In many cases proper alignment is very difficult because of the thinness of material forming the housing or end cap and the possibility of shifting of the housing configuration during use. When there is no alignment the end cap will not be held firmly in place on the housing.

Furthermore, prior art end cap structures lack esthetic appeal because of the need of surface distractions such as screws or dimples formed along the turned edge portion of the end cap on the visible side thereof.

SUMMARY OF THE INVENTION Accordingly, it is an object of this invention to provide an end cap structure which insures exact alignment of a protuberance with a dimple formed in the surface of the housing receiving the end cap.

Another object of this invention is to provide an end cap structure which is securely fastened to housing members without the use of screws or external dimples formed along the turned edges of the end cap.

Still another object of this invention is to provide an end cap structure which is simple and inexpensive to manufacture and efficient and reliable in use.

A feature of this invention is utilizing a housing member either totally formed of a plastic material or having a plastic coating thereon, such as over a sheet metal support, which plastic material or coating will cold flow under prolonged pressure.

Briefly, the end cap structure disclosed herein is shown in connection with a housing for a blacklight fluorescent lamp unit and is illustrated to show one preferred form of the invention. However, the end cap structure generally can be used on any housing configuration and for any suitable purpose. Preferably the housing to receive the end cap is formed of a plastic covered sheet metal as is well known for simulating wood grain or other textured surfaces on sheet metal such as sheet aluminum or sheet steel. Preferably, the end cap is molded plastic and has turned edges along the periphery thereof and has a configuration to receive the housing inwardly of the turned edges. On the inside of the turned edges is formed one or more protuberances which will engage the housing under pressure when the end cap is applied thereto. The plastic covering on the housing, as a result of the pressure exerted by the protuberance, will cold flow sufficient to form a deformation in the covering. This deformation will produce a dimple exactly under the protuberance for perfect alignment therewith ultimately to securely hold the end cap in position. Generally, the plastic covering on the housing will cold flow in approximately two to five days and produce the desired dimple. However, the

length of time needed to cause cold flow of the plastic covering is dependent on, among other things, the ambient temperature and the pressure of the protuberance in contact therewith. Positioned on each side of each protuberance is a back-up post which extends from the end cap wall and parallel to the turned edge. The sheet metal is held firmly between the protuberance and the back-up post to supply the proper pressure to cause cold flow of the plastic covering. Preferably the backup posts have the upper ends thereof relieved to act as guide. surfaces during application of the end cap to the housing structure.

Other objects, features and advantages of this invention will be more fully realized and understood from the following detailed description when taken in conjunction with the accompanying drawings wherein like reference numerals throughout the various views of the drawings are intended to designate similar elements or components.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a front view of a blacklight fluorescent lamp structure which has a housing for receiving a pair of end caps in accordance with this invention;

FIG. 2 is a sectional view through line 22 of FIG.

FIG. 3 is a sectional view through line 33 of FIG.

FIG. 4 is an enlarged fragmentary view, corresponding substantially to that of FIG. 3, but showing the plastic coating deformed to create a dimple in accordance with this invention; and

FIG. 5 is a top view of the fragment shown in FIG. 4.

DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS Referring now to FIG. 1 there is seen a light assembly designated generally by reference numeral 10. The light assembly 10 is here shown as a blacklight fluorescent lamp unit used for decorative or display purposes. The light assembly 10 has a housing 12 preferably of plastic covering metal, such plastic coverings being of a wood or other decorative texture. A reflector unit 13 is mounted within the housing and has high gloss surfaces l3a, 13b and at angles relative to one another to direct the light from a fluorescent lamp 14 in a given direction. While the end cap structure of this invention is shown in connection with the lamp assembly 10, it will be understood that the novel aspects of this invention can be incorporated in connection with end caps for other structural devices.

Most advantageously, a pair of end caps 16 are secured to each end of the housing 12 and firmly held in place on the housing in accordance with the principles of this invention. The end caps 16 preferably are of molded plastic construction and are fonned of any suitable moldable plastic material.

Referring now to FIG. 2, which is a section view of the end cap FIG. I, the end cap 16 has the turned edges 16a thereof surrounding the housing 12. That is, the peripheral edge portion of the end cap has a configuration corresponding substantially to the configuration of the housing. The housing 12 is positioned inwardly of the turned edges 16a and has a discrete elemental area thereof in contact witha plurality of protuberances l8 strategically located on the turned edges 16a. Positioned on each side of the protuberances 18 are back-up

posts

19 and 20 to hold the sheet metal of the housing 12 toward the protuberances,

As best seen in FIG. 3, the back-up

posts

19 and 20 have slanted guide surfaces 19a and 200 at the top of each post and they serve to direct the wall portion of the housing 12 between the back-up posts and. the protuberance 18. In FIG. 3 the housing portion 12 is shown as a sheet metal structure 120 with a plastic covering 12b. The plastic covering preferably is of a nature that will cold flow from pressure over a prolonged period of time, polyvinyl chloride being a preferred example.

In accordance with this invention, the protuberance 18 will then cause cold flow of the plastic covering 121; immediately under the protuberance to form a deformation 22, as seen in FIG. 4, in exact registry with the protuberance. This deformation is a dimple in the skin of the housing and serves to hold the end cap firmly in position.

This is further shown in FIG. 5 which indicates that the deformation 22 causes the wall portion of the housing 12 to move slightly toward the turned edge 16a while still maintaining the backside thereof in contact with the back-up

posts

19 and 20. Therefore, the backup posts 19 and 20 are slightly urged away from the protuberance 18 upon initial insertion of the wall 12 therebetween, and after several days of constant pressure of the protuberance against the plastic covering 12!) the plastic covering will cold flow to form the dimple.

Subsequent removal of the end cap 16 can be accomplished by exerting sufficient force to cause the protuberance to part from the dimple. Thereafter a second fastening or connecting of the end cap to the housing 12 is readily accomplished and exact alignment of the protuberance and dimple are achieved since the protuberance itself created the dimple in the first instance.

What has been described is a simple efficient end cap structure for use in closing off a housing formed with a plastic coating or, the end cap can be used on solid plastic housings wherein the surface portion of the housing will cold flow as described herein. Accordingly, variations and modifications of this invention may be effected without departing from the spirit and scope of the novel concepts disclosed and claimed herein. Techniques for bonding polyvinyl chloride and other sheet plastic material to metal are well known, and hence are not disclosed herein. Alternatively, the covering could be a coating applied to the metal rather than a discrete sheet bonded thereto.

The invention is claimed as follows:

I. An end cap structure comprising an end wall portion to be positioned over an open end of a thin wall housing, said end wall portion having turned edges with a peripheral configuration corresponding to that of the housing to receive said end cap, at least one protuberance formed on said turned edges on the inner side thereof to come in pressing contact with the material forming the housing, and back-up means formed on said end wall portion adjacent said protuberance and parallel to said turned edges and positioned to receive a wall portion of the housing between said protuberance and said back-up means, said back-up means being formed by a pair of yieldable post members, each post member being located on opposite sides said protuberance and spaced from said turned edges a distance to provide a space between the peripheries said protuberance and said pair of post members which is less than the thickness ofa wall portion of the thin wall housing inserted therein.

2. The structure of claim 1 wherein said pair of post members have guide surfaces formed at their upper ends to guide the wall portions of the housing between said protuberance and said back-up post members.

3. An structure for a blacklight housing containing spaced apart sockets to receive a black-light fluorescent lamp and a reflector positioned behind the lamp and electric circuit means in the housing, to control energization of the lamp, said structure comprising in combination, a housing portion formed of smooth sheet material of predetermined thickness having an open portion to be capped, an end cap having an end wall portion to be positioned over said open portion, said end cap having turned edges, said turned edges having a peripheral configuration to conform substantially to the outer configuration of said housing portion at the open portion thereof, said housing portion being positioned inwardly of said turned edges, at least one protuberance formed on said turned edges on the inner side thereof to come into pressing contact with the smooth sheet material forming said housing portion, a pair of yieldable post members formed on said end wall portion parallel to said turned edges, each post member being located adjacent to and on opposite sides of said protuberance and spaced from said turned edges a distance to provide a space between the peripheries said protuberance and said pair of post members which is less than said predetermined thickness of said sheet material.

4. The structure of claim 3 wherein said back-up posts have guide surfaces formed at their upper end to insure that said sheet material will be directed between said protuberance and said back-up post.

5. The structure of claim 3 wherein said smooth sheet material is formed of a plastic covering over sheet metal and said plastic covering is deformed under prolonged pressure of said protuberance.

6. An structure comprising in combination, a housing formed of smooth sheet material of predetermined thickness having an open portion to be capped, an end cap having an end wall portion to be positioned over said open portion, said end cap having turned edges, said turned edges having a peripheral configuration to conform substantially to the outer configuration of said housing at the open portion thereof, said housing being positioned inwardly of said turned edges, at least one protuberance formed on said turned edges on the inner side thereof to come into pressing contact with the smooth sheet material forming said housing, back-up means formed by a pair of yieldable post members on said end wall portion parallel to said turned edges, each post member being located adjacent to and on opposite sides of said protuberance and spaced from said turned edges a distance to provide a space between the peripheries of said protuberance and said pair of post members which is less than said predetermined thickness of said sheet material and a deformation formed in said smooth sheet material as a result of cold flow at the surface of said material caused by the pressure contact of said protuberance, whereby said deformation forms a dimple under said protuberance to hold said end cap to said housing.

7. The structure of claim 1 wherein said back-up posts have guide surfaces formed at their upper end to insure that said sheet material will be directed between said protuberance and said back-up post.

8. The end cap structure of claim 6 wherein said smooth sheet material is formed of a plastic covering over sheet metal and said plastic covering is deformed under prolonged pressure of said protuberance.

Claims

1. An end cap structure comprising an end wall portion to be positioned over an open end of a thin wall housing, said end wall portion having turned edges with a peripheral configuration corresponding to that of the housing to receive said end cap, at least one protuberance formed on said turned edges on the inner side thereof to come in pressing contact with the material forming the housing, and back-up means formed on said end wall portion adjacent said protuberance and parallel to said turned edges and positioned to receive a wall portion of the housing between said protuberance and said back-up means, said back-up means being formed by a pair of yieldable post members, each post member being located on opposite sides said protuberance and spaced from said turned edges a distance to provide a space between the peripheries said protuberance and said pair of post members which is less than the thickness of a wall portion of the thin wall housing inserted therein.