Patent Publication Number: US-5299108-A

Title: Disposable-type flashlight

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates generally to flashlights and more particularly to compact, disposable-type flashlights that are operated by squeezing a case of the flashlight. 
     2. Prior Art 
     Compact, disposal-type flashlights are well known and have been available for a number of years. 
     One early disposable-type flashlight is disclosed in U.S. Pat. No. 3,797,869. This flashlight includes a switch wire which may be pressed against an uninsulated can of one of two batteries to close an electrical circuit of the flashlight. This circuit includes a bulb having two lead wires welded respectively to a positive terminal of one battery and a negative terminal of the other battery. 
     U.S. Pat. No. 4,429,352 discloses the first inventive flashlight of the inventor of a herein disclosed still further improved lighting instrument. The bulb of this flashlight also has two lead wires. A first lead wire is attached by a solder joint to a positive front terminal end of one battery while the second lead wire functions as a switch. Compression of a case of the flashlight bends the second lead wire to engage a connector strap and close a circuit of the flashlight to energize the bulb. 
     A second inventive flashlight from this inventor is set out in U.S. Pat. No. 4,819,140. In this flashlight one of the two bulb lead wires is bent forward over the bulb. Compression of the flashlight case presses one arm of a U-shaped spring switch into contact with this forward bent lead wire to close a circuit on the flashlight and connect the batteries with the bulb. 
     SUMMARY OF THE INVENTION 
     A still further improved disposable-type flashlight of this invention includes a hollow, pliable case. Carried in the case is a hollow core piece that holds a pair of oppositely positioned batteries against an inner wall of the case. Connecting oppositely charged front terminal ends of the batteries is a conductive front contact member having a hat-like shape. A front lens of a bulb of the instrument is contained in an opening in a web of the front contact member. An inner terminal end of the bulb then is carried in a front end opening of the core piece. 
     A base segment of a conductive switch fits against a rear end of the core piece to engage a rear terminal end of one battery. The switch base segment connects spaced apart, flexible arms that extend forward so that an end tip of each arm locates adjacent to a base terminal portion of the bulb. 
     A flange of a conductive connector strip is positioned opposite the switch base segment to engage a rear terminal end of the other battery. The strip then extends forward into an inner space of the core piece where a flexible end of the strip engages the bulb inner terminal end. 
     To complete assembly of the flashlight caps are placed over a front and rear end of the case with the bulb lens end extending outward from an opening in the front end cap. As affixed to the case, the caps compress the various components therein. This compressive force produces a slight flexing of the front contact member and the connector strip. 
     To operate the flashlight one squeezes the case forcing the end tip of either switch arm against the bulb base terminal portion. The resulting engagement closes an electric circuit comprising the bulb, batteries, front contact member, switch, and connector strip. Current from the batteries flows to energize the bulb and produce illumination. 
     The flashlight of this most recent invention provides several improvements not known or presently available in other disposable-type flashlights. 
     To appreciate these improvements and resulting advantages, one must understand that for a disposal-type flashlight to be commercially successful, that flashlight must operate reliably and be competitively priced. These criteria in turn require an availability of high quality components in large quantities. 
     A first advantage of this improved flashlight is that large quantities of high quality components for this flashlight may be mass-produced at a reasonable cost. 
     A second advantage is that these components then may be quickly assembled into reliably working flashlights. Of particular importance to promoting reliability is that the bulb of this flashlight does not have lead wires, common to most other available assemblies. Typically, bulb lead wires are connected to other circuit components by a solder joint. Such joints are subject to failure because of their inherent structural weakness. Additionally, bulb lead wires have been known to break or become dislocated and cause a short circuit. Further, any excessive heat used to form a solder joint can be detrimental to the batteries. 
     In this inventive flashlight all of the circuit components first are positively located and then connections between these components are held together by a continuing compressive force. Resulting friction produces high-quality conductive interfaces. This continuing compressive force results from a flexing of the front contact member and connector strip. The spring-like nature of these components also accommodates dimensional variations of the batteries and the bulb. The bulb and batteries are staple-like purchased components; as such, they are not manufactured to exacting dimensional tolerances. 
     Reliability is further advanced by component symmetry. Components may be in a flip or flopped position for assembly. No component has just one usable position. For example, neither the core piece nor the switch has a defined top or bottom side. The front contact member has no defined right or left side. While the batteries must be positioned in an opposing manner, the batteries are identical and interchangeable. Further, the position of the switch end segment and the connector strip flange with respect to the core piece may be reversed. This invertibility and reversibility reduces the time of assembly and minimizes assembly error. 
     Ease of assembly is further advanced by the core piece. The core piece positively holds the switch and connector strip and helps position the bulb and batteries. As secured to the core piece, these components then may be readily inserted into the case. The core piece then maintains the position of these components within the case as discussed above. 
     A still further advantage is that this inventive flashlight is easy to operate. The length of the switch arms allows the case to be squeezed almost anywhere with lesser force to activate the flashlight. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a flashlight of this invention; 
     FIG. 2 is an exploded view in perspective of components of the flashlight of FIG. 1; 
     FIG. 3 is a cross sectional view of the flashlight as seen generally along the line 3--3 of FIG. 1; 
     FIG. 4 is an elevation view of a rear end of a core piece of the flashlight; 
     FIG. 5 is a side elevation view in cross section of the core piece as seen generally along the line 5--5 of FIG. 6; and 
     FIG. 6 is an elevation view of a front end of the core piece. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     A flashlight of this invention is shown generally in FIG. 1 and designated 10. The flashlight 10 includes a hollow, oval-like shaped case 12. This case 12 is made of a thin, pliable plastic material which preferably is translucent. When the case 12 is translucent, a paper lining 14 may be carried snugly in the case 12 so that advertising indicia 16 printed on the paper liner 14 is visible therein. 
     Fitted over a front end 18 and a rear end 20 of the case 12 is a respective cap 22. In an end wall 26 of each cap 22 is an opening 28. A peripheral sidewall 30 then extends inward from each cap end wall 26 to fit tightly about the front end 18 and the rear end 20 of the case 12. 
     In the opening 28 of the rear end cap 22 is a key ring holder 32 having an inner end flange 34 that abuts against an inside surface 36 of the cap end wall 26. A slotted outer end 38 of the holder 32 then extends from the opening 26. Projecting through the opening 28 of the front end cap 22 is an outer lens end 40 of a bulb 42. This bulb 42 has a 2.5 volt rating. 
     Interior structure of the flashlight 10 can best be understood by viewing FIGS. 2-6. Inside the front end cap 22 is a hat-like shaped front contact member 46. This contact member 46 is made of a flexible, conductive material and includes a web 48 formed with an opening 50. The web 48 connects a pair of spaced apart legs 52 positioned on an angle so that the legs 52 flare slightly apart. On the end of each leg 52 is a respective contact flange 54a, 54b positioned on a slight angle to flare away from the web 48. The bulb lens end 40 extends through the contact member web opening 50 with a shoulder 56 of the bulb 42 fitting against the web 48. 
     As shown in FIGS. 2 and 3, an inner terminal end 58 of the bulb 42 is carried in an opening 60 in a front end 62 of a core piece 64. As located, the bulb inner terminal end 58 locates in a rectangular-shaped, hollow inner space 66 of the core piece 64. Projecting forward from the core piece front end 62 and positioned about the opening 60 is a set of four posts 68 which fit about a terminal base portion 70 of the bulb 42. These posts 68 help secure the bulb 42 during assembly of the flashlight 10 and then inhibit any inadvertent contact between the bulb base terminal portion 70 and the front contact member 46. 
     The core piece 64, see FIGS. 2 and 4-6, has an elongated body 72 formed with recessed sidewalls 74 sized to hold respectively a pair of quad-A, alkaline batteries 76a, 76b. Each battery 76a, 76b has a 1.5 volt rating. Additionally, the core piece sidewalls 74 are spaced apart to locate the batteries 76a, 76b firmly against the paper liner 14 inside the case 12. The batteries 76a, 76b are positioned in an opposing manner so that, for example, a front terminal end 78a of the battery 76a is positively charged while a front terminal end 78b of the battery 76b is negatively charged, see FIG. 2. 
     A rear end 80 of the core piece 64 has a top and bottom flange 82. In each flange 82 is a slot 84 to hold respective arms 86 of a switch 88. The switch 88 is made of a flexible, conductive material with the arms 88 connected by a base segment 90. This base segment 90 fits against the core piece rear end 80 to in part cover an rear end opening 92 to the core piece inner space 66. A contact extension 94 of the segment 90 then engages a rear terminal end 96b of the battery 76b. 
     The switch arms 86 extend forward and outward on an angle. This angle is such that a forward end portion 98 of each arm 86 is flexed inward by contact with the case 12 at a point near the front end 62 of the core piece 64. Each arm 86 then has an inwardly offset contact tip end 100 that locate near and on each side the bulb terminal base portion 70. 
     The switch base segment 90 has a notch 102 opposite the contact extension 94, see FIG. 2. A connector strip 106 extends through this notch 102 and the core piece rear end opening 92 and into the core piece inner space 66. This strip 106, also made of a flexible, conductive material, has a rear end contact flange 108 that engages a rear terminal end 96a of the battery 76a. A front end portion 110 of the connector strip 106 has a narrowed width and is offset on an angle to engage the inner terminal end 58 of the bulb 42. 
     To locate the connector strip 106 within the core piece inner space 66, a top and a bottom wall 112, 114 of the inner space 66 each has a set of ribs 116, see FIG. 4. Each rib set 116 is spaced inward from respective sidewalls 118 of the core piece inner space 66 to form glide slots 120a, 120b. As shown, the connector strip 106 is located in the glide slot 120a. 
     The caps 22 are affixed to the case ends 18, 20 to apply a slight compressive force to various connections between elements comprising an electric circuit of the flashlight 10. For example, the caps 22 force the switch base segment 90, connector strip contact flange 108, batteries 76a, 76b, and flanges contacts 54a, 54b of the front contact member 46 together. Because the flange contacts 54a, 54b are on a slight angle, this force flexes the legs 52 of each contact flange 54a, 54b slightly apart. This flexing of the legs 52 produces a reactive force which then maintains the connections between these components is a compressive state. 
     In a like manner the caps 22 force the connector strip 106, bulb 42, and front contact member web 48 together. Force applied to this second element grouping flexes the connector strip front end portion 110 and the front contact member web 48. This further flexing then maintains connections between these components in a like compressive state. The core piece 64 and the case 12 inhibit component dislocation induced by this compressive state. 
     Upon assembly the flashlight 10 is operated by compressing the case 12. Compression of the case 12 presses the switch arms 86 inward so that at least one arm contact tip 100 engages the bulb terminal base portion 70. This engagement in turn closes the circuit of the flashlight 10 so that electric current may flow from the batteries 76a, 76b to the bulb 42. The now energized bulb 42 produces illumination. 
     While an embodiment, uses and advantages of this invention have been shown and discussed, it should be understood that this invention is limited only by the scope of the claims. Those skilled in the art will appreciate that various modifications or changes may be made without departing from the scope and spirit of the invention, and these modifications and changes may result in further uses and advantages.