US2890327A - Flashlight construction - Google Patents

Description

June 9, 1959 YlCK c. CHENG 2,890,327

FLASHLIGHT CONSTRUCTION I 7 Filed July is, 1955 1N VENTOR 7 BY Elm ATTORNEYS United States Patent FLASHLIGHT CONSTRUCTION Yick C. Cheng, Kowloon, HOllg Kong, assignor, by mesne assignments, to The Electric Storage Battery Company, Philadelphia, Pa., a corporation of New Jersey Application July '19, 1955, Serial No. 523,093

4 Claims. (Cl. 240-106) This invention relates to a novel type of insulator for the reflector bowl of a flashlight, whose function is to insulate the electrically conductive undersurface of the reflector bowl from the metallic flashlight casing. A

- particularly desirable feature of the insulator of the present invention is the tight seal which may be obtained between the lens of the flashlight and the reflector bowl.

Very little attention has been devoted in the past to this structural component of a flashlight. In a typical lens and reflector assembly for a flashlight, a primary component of the assembly is the lens ring having some type of flanged aperture, with the glass or plastic lens positioned in abutment against the flange. Seated against the flat undersurface of the lens is a reflector bowl having a reflective metal surface, and an undersurface coating of electrically conductive copper, with an open, centrally disposed, threaded cylinder within which the lamp is secured. Ordinarily, the electrical circuit in the flashlight is completed by a contact strip in physical and electrical contact with the undersur-face of the reflector bowl. Usually, both the contact strip and the metallic flashlight casing are in electrical contact with the bottom terminal of a dry cell in the flashlight. In order to avoid continuous operation of the light, and allow for the use of a control switch in the circuit, it is therefore essential that the reflector bowl be carefully electrically insulated from the metallic flashlight casing. This is accomplished frequently by a strip of cardboard or a like insulating material which is inserted in some fashion between the reflector and the flashlight casing.

In order to maintain the reflector in engagement with the lens and lens ring and to prevent accidental dislocation of the respective component parts of this assembly, there is frequently provided a helical spring of strong wire which engages both the reflector bowl and the interior surface of the flashlight casing. This spring forces the reflector against the lens. In order to prevent electrical contact between the casing and the reflector bowl through the metallic wire spring, at least part of the spring is usually electrically insulated by a thin plastic sleeve, frequently referred to as spaghetti.

With a lens and reflector assembly of this type, it was found that the earliest point at which deterioration of the flashlight casing was noticeable was the exposed metallic surface of the reflector bowl. This was particularly noticeable in warm, humid climates. Another frequent source of trouble in such a flashlight assembly was in the lens. It was found that a glass lens in particular was susceptible to cracking upon sudden impacts, such as would be caused by dropping the flashlight against a hard surface. Still another drawback to a construction of this type is the large amount of labor required for the complex assembly operations involved in placing the cardboard insulating piece and the insulated spring in position.

Accordingly, it is an object of the present invention to provide a novel type of plastic insulator which will be sturdy, simple to assemble, and which will eliminate a large percentage of the labor requirement for assembly of the lens and reflector components.

Another object of the invention is to provide a resilient, 5 plastic insulator which will also function as a gasket between the reflector bowl and the lens, whereby an airtight seal may be obtained between the lens and reflector bowl for the elimination of corrosion of the interior exposed metallic surfaces of the reflector bowl.

Yet another object of the invention is the provision of a resilient gasket between the lens and reflector bowl in the front end cap assembly of a flashlight, in order to minimize the effect of impact shocks on the front end cap assembly by providing a cushion between the lens and the reflector bowl.

A still further object of the invention is to provide an insulator for a flashlight reflector bowl which will also function to insulate a piano wire spring used in the assembly from the reflector bowl.

These and other objects of the invention are achieved by the novel plastic insulator of the present invention. This insulator is in the form of a cylindrical ring of U-shaped cross-section, with the inner wall or web of the U being slightly inturned and inclined to the vertical, 5 while the outer web or wall of the U is in the form of a wall of a cylinder. Integrally secured to the outer wall of the ring at the point where it unites with the bight of the U, there is an upwardly and inwardly directed flange which forms a recessed channel with the 0 bight of the U. The peripheral flange conventionally provided on a reflector bowl, as a bearing surface against the lens, may be seated within this recessed channel. The portion of the plastic insulator which is interposed between the peripheral flange of the reflector bowl and the lens forms a resilient cushion between the lens and the reflector bowl. This cushion decreases the effect of sharp impacts on the lens, and at the same time, when 'placed under slight compression, forms a hermetic seal between the lens and the reflector bowl. Such a seal is very advantageous in preventing corrosion of the reflector bowl. Where it is desired to use a wire spring to urge the reflector bowl into contact with the lens, the wire spring may be seated within the bight of the U- shaped ring which encloses it sufliciently so that there need be no additional insulation placed on the wire spring itself.

These and other features of the invention may be best understood by reference to the drawings, in which:

Fig. 1 is a side elevational view of a flashlight lens and reflector assembly according to the present invention, in partial section; I

Fig. 2 is a top plan view of the reflector insulator;

Fig. 3 is a plan view of the undersurface of the reflector insulator;

Fig. 4 is a sectional view of the reflector insulator taken on line 44 of Fig. 2.

Referring now in detail to the drawings, a flash-light casing 11 is provided with a conventional type of lens ring 10 having an inturned lip 9 against which a lens 14 is positioned in abutting relation. Seated against the lens is a reflector bowl 12, the peripheral flange 21 of which bears against the inner surface of the lens. Seated around the reflector 12 and embracing the peripheral flange 21 thereof with in a recess 18 therein, is the reflector insulator 13. Interposed between the peripheral flange 21 and the opposed surface of the lens 14 is the upper extremity or lip 23 of an inwardly directed flange 19. Extending inwardly and downwardly, in snug engagement with the underlying undersurface of the reflector bowl, is an inner web 17. The snug engagement between the web 17 and the underlying undersurface of the reflector bowl enhances the pneumatic seal which is obtainedbetween the peripheral-flange 21 of the reflector bowl and the lens 14, and at the same time insulates the undersurface of the reflector bowl 12 against contact with the flashlight casing 11 and the metallic front end cap 10. Another integral part of the reflector insulator is an abbreviated cylindrical tube or apron 16, which forms the outer wall of a ring of substantially U-shaped cross-section. The abbreviated cylindrical tube 16 adds rigidity to the structure and facilitates the insertion of the peripheral flange 21 of the reflector bowl within the recessed channel 18 in the reflector insulator. The cylindrical tube 16 also forms the outer wall of a pocket within which the wire spring may be seated in insulated relationship with respect to the undersurface of the reflector bowl 12. The wire spring 15 may be seated against the bight 20 of the U-shaped ring, and at its other extremity may beseated against a shoulder within the flashlight end cap 10.

The slight compression applied by the wire spring 15 suflices to urge the peripheral flange 21 of the reflector bowl into a mild compressive engagement with the inner surface of the lens 14., The mild compression desirably distorts the lip 23 of the reflector insulator so that it functions as a gasket and forms an air-tight seal between the glass lens 14 and the interior of the reflector bowl 112. In order to obtain this gasket effect, it is necessary that the reflector insulator be constructed of a resilient material. Two highly satisfactory plastics for the construction of the reflector insulator, of the several which may be employed, are the polyvinyl plastics and the polyethylene plastics. The particular plastic employed may be selected on the basis of its strength characteristics, appearance, ease of handling, age-resistance and insulating properties. Of these plastics, a polyethylene plastic having a molecular weight in the range of 10,000 to 20,000 is preferred.

While it is preferred that the reflector insulator disclosed be employed in combination with a wire spring of the type illustrated in Fig. 1, so that a mild compressive action is obtained, and so that accidental dislocation of the lens and reflector assembly during this assembly or reassembly of the entire flashlight is prevented, it should be understood that the presence of the wire spring 15 is not essential in the assembly. The wire spring 15 may be omitted in many cases, and suflicient compressive relation to obtain the gasket eifect from the reflector insulator may be obtained through the action of a conventional bottom spring in the flashlight casing. Other minor modifications in the basic structure disclosed, which are within the scope of the invention, will occur to those skilled in the art.

I claim:

1. In an improved flashlight structure, a lens ring and a lens, a peripherally flanged reflector bowl in juxtaposition with said lens, a resilient plastic gasket interposed between the lens and peripheral reflector bo'wl flange toobtain a tight seal, said gasket embracing the flange in seating engagement within a channel therein, said gasket having a dependent integral Web snugly embracing the undersurface of said bowl to insulate it from the flashlight casing, said gasket also having a second dependent integral web in abbreviated cylindrical form, said webs being integrally interconnected in a structure of inverted U-shaped cross-section, and a wire spring seated against the bight of said U and engaging the walls of the flashlight casing, said spring biasing the reflector bowl toward engagement with the lens and thereby compressing the resilient gasket.

2. In an improved flashlight structure, a lens ring and lens, a peripherally flanged reflector bowl spring-biased into juxtaposition with said lens, and a resilient plastic gasket element part of which is interposed under com.- pression between the lens and reflector bowl flange, whereby a tight seal is obtained, said gasket element having a channel within which the reflector bowl flange is seated; a dependent web snugly embracing the undersurface of said bowl and insulating it from the flashlight casing while providing a seal between the lens and the interior of the reflector bowl; a second dependent web of abbreviated cylindrical form attached at one end about said gasket element, said second dependent web imparting rigidity to said gasket element, said dependent webs forming between them an inverted recessed seat for a biasing spring.

3. In a flashlight having a cap, a lens and a reflector bowl below said lens, said bowl having a peripheral flange at the top thereof, the improvement which cornprises; an integral resilient sealing and insulating clement, said element having an interior annular channel embracing the said flange of said bowl thereby providing a lip portion interposed between said lens and said flange, said element having a downwardly depending, inwardly in clined annular web below said channel, said web being shaped to conform to and embrace the other portion of said bowl below the flange thereof, said element having a second integral, downwardly depending annular web outwardly spaced from said downwardly inclined web, thereby providing a recessed inverted scat between said webs.

4. The improvement claimed in claim 3 in which a wire spring is confined under compression between the said flashlight cap and the said recessed inverted seat, said spring biasing the reflector bowl toward the lens and thereby compressing the said interposed lip portion of said resilient sealing and insulating element.

References Cited in the file of this patent UNITED STATES PATENTS 1,299,909 Burgess Apr. 8, 1919 1,560,278 Mahan Nov. 3, 1925 1,595,146 Ford Aug. 10, 1.926 2,264,284 Bassett Dec. 2, 194] 2,304,742 Officer Dec. 8, 1942 2,602,114 Fisch July 1, 1952 2,613,314 Garland Oct. 7, 1952 FOREIGN PATENTS 489,382 Great Britain July 26, 1938

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