FLASHLIGHT

Abstract: A flashlight (20) includes a barrel (21) for retaining batteries (31). A reflector (51) and lens (26) located at one end is rotatable axially to vary the reflection dispersion of a light beam emanating through the lens (26) from a lamp bulb (45). An internal cylindrical sleeve (100) within the barrel (21) provides the electrical path between a tail cap (22) adjacent the one electrode end (35) of the batteries (31) and the end (101) adjacent the reflector, lens, and bulb. The sleeve (100) is a non-ferrous nickel plated material for improved conductivity between component parts.

Description: The present invention relates primarily to flashlights, and in particular, to a miniature hand-held flashlight. Flashlights of varying sizes and shapes are well-known in the art. In particular, certain of such known flashlights utilize two or more dry cell batteries, carried in series in a cylindrical tube serving as a handle for the flashlight, as their source of electrical energy. Typically, an electrical current is established from one electrode of the battery through a conductor to a switch, then through a conductor to one electrode of the lamp bulb. After passing through the filament of the lamp bulb, the electrical circuit emerges through a second electrode of the lamp bulb in electrical contact with a conductor, which in turn is in electrical contact with the flashlight housing. The flashlight housing usually provides an electrical conduction path to an electrical conductor, generally a spring element, in contact with the other electrode of the battery. Actuation of the switch to complete the electrical circuit enables electrical current to pass through the filament, thereby generating light which is typically focused by a reflector to form a beam of light. The production of light from such flashlights has often been degraded by the quality of the reflector utilized and the optical characteristics of any lens interposed in the beam path. Moreover, intense light beams have often required the incorporation of as many as seven dry cell batteries in series, thus resulting in a flashlight having significant size and weight. Efforts at improving such flashlights have primarily addressed the quality of the optical characteristics. The production of more highly reflective, well-defined reflectors, which may be incorporated within such flashlights, have been found to provide a more well-defined focus thereby enhancing the quality of the light beam produced. Additionally, several advances have been achieved in the light admitting characteristics of flashlight lamp bulbs. Since there exists a wide variety of uses for hand-held flashlights, the development of the flashlight having a variable focus, which produces a beam of light having a variable dispersion, has been accomplished. However, such advances have heretofore been directed at "full-sized" flashlights. In a flashlight which is made of metal body such as aluminum many manufacturing processes are necessary to ensure that effective electrical conductivity and contact can be maintained through the metal body. These processes can be relatively expensive steps in the overall manufacturing procedures. Some of these processes require multiple machining, anodizing and degreasing steps of the various metal elements. Moreover, it is desirable to ensure that the electrical conductivity between conductive elements does not deteriorate due to corrosion effects which may be caused by electrolysis through the interaction between different kinds of metal, such as copper and aluminium, which may form part of the electrical circuit. It is an object of the present invention to provide a flashlight having improved electrical conductivity and optical characteristics while being capable of producing a beam of light having a variable dispersion with the relative motions of components that produce the variation and the dispersion of the light beam, provide an electrical switch function to open and complete the electrical circuit of the flashlight in an advantageous manner. FR-A-2 372 382 discloses a flashlight in accordance with the preamble of claim 1. In this prior construction, the annular lip of the conductive element is outwardly directed with the consequence that not only the bulk of the forward end of the flashlight is necessarily increased but also the arrangement is necessarily such that it is rearward movement of the head assembly which causes closure of the electrical connection. With the present invention, as defined in claim 1, a compact head assembly can be utilised with the inwardly directed lip enabling the arrangement to be such that the electrical connection is open when the head assembly is in its rearward most position facilitating control of operation of the flashlight and enabling the lamp to be illuminated, even when the head assembly is removed completely. The structure according to claim 1 provides a head assembly which engages threads formed on the exterior of the barrel such that rotation of the head assembly about the axis of the barrel changes the relative displacement between the lens, or the reflector and the lamp bulb. When the head assembly is fully rotated onto the barrel, the reflector pushes against the forward end of the lamp holder assembly causing it to shift rearward within the barrel against the urging of the spring contact at the tail cap. In this position, the electrical conductor within the lamp holder assembly which completes the electrical circuit from the lamp bulb to the barrel is not in contact with the cylindrical sleeve or barrel. Upon rotation of the head assembly in a direction causing the head assembly to move forward with respect to the barrel, pressure on the forward surface of the lamp holder assembly from the reflector is relaxed enabling the spring contact in the tail cap to urge the batteries and the lamp holder assembly in a forward direction. This brings the electrical conductor into contact with the cylindrical sleeve, thereby completing the electrical circuit and causing the lamp bulb to illuminate. At this point, the lamp holder assembly engages a stop which prevents further forward motion of the lamp holder assembly with respect to the cylindrical sleeve and barrel. Continued rotation of the head assembly in a direction causing the head assembly to move forward relative to the barrel causes the reflector to move forward relative to the lamp bulb. This changes the focus of the reflector with respect to the lamp bulb, which results in varying the dispersion of the light beam admitted through the lens. US-A-4 570 208 discloses a flashlight which utilises a switch assembly separate from the movable head structure carrying the reflector such that control of the reflector for varying beam shape is quite divorced from the operation of the switch which itself is mounted in a non-sealing manner on the barrel of the flashlight. The present invention as defined in claim 1 provides for varying degrees of the same axial movement of the head structure carrying the reflector on the barrel to provide both the on/off switching action and control of beam shape. With this structure, there is no need to provide an additional aperture through the barrel for switching purposes with the switching action itself being caused by engagement of a contact with an inwardly directed lip, whereby good electrical contact is ensured. While GB-A-2 107 038 discloses an electrical lamp in which axial movement of a head provides both the switching function and the beam control function, there is no suggestion of the use of an annular connecting element, reliably engageable by a contact in various adjusted positions of the head structure. While US-A-4 220 985 discloses a light in which a narrow head assembly is screwed relative to the barrel to engage contacts to provide illumination of the lamp, this prior construction operates in a similar manner to the construction of FR-A-2 372 382, discussed above in that there is no appreciation as to how, by using an inwardly directed lip, it can be arranged for the lamp to be switched off when the head assembly is screwed in, rather than being switched on in that position. Although not shown in FR-A-2 372 382, the use of a parabolic reflector and a detachable tail cap is known elsewhere, for example in US-A-4 527 223. Preferably, the batteries are of the size commonly referred to as "pen light" batteries. In the preferred embodiment later described in detail, the conductive element is a non-ferrous material such as brass and is nickel-plated. This ensures effective conductivity with engaging adjacent parts connected in electrical circuit with the battery electrodes and the spring member in the tail cap. By rotating the head assembly until it disengages from the barrel, the head assembly may be placed, lens down, on a substantially horizontal surface and the tail cap and cylindrical tube may be vertically inserted therein to provide a "table lamp". Brief Description of the Drawings Figure 1 is a partially foreshortened cross-sectional view of a flashlight with an internal cylindrical sleeve; Figure 2 is a partial cross-sectional view of a forward end of a flashlight of Figure 1, illustrating, in ghost image, a translation of the forward end of the flashlight; Figure 3 is a perspective view of a cylindrical internal sleeve for the flashlight; Figure 4 is a partial foreshortened cross-sectional view of a flashlight with an internal cylindrical sleeve and with a head assembly having a gradually tapering outside surface; Figure 5 is a partial foreshortened cross-sectional view of a portion of a flashlight with an internal sleeve and with a head assembly having a gradually tapering concave outside surface. The overall construction of the flashlight of Figures 1, 2, 4 and 5 is basically similar. In the embodiments of Figures 1, 2, 4 and 5, there is an internal cylindrical sleeve. The construction of the flashlight is now described. A flashlight 20 is comprised of a generally right circular cylinder, or barrel 21, enclosed at its rear end by a tail cap 22 and having a head assembly 23 enclosing the forward end thereof. The head assembly comprises a head 24 to which is affixed a face cap 25 which retains a lens 26. The head assembly 23 has a diameter greater than that of the barrel 21 and is adapted to pass externally over the exterior of the barrel 21. The barrel 21 provides a machined handle surface 27 along its axial extent. The tail cap 22 is configured to include provision for attaching a handling lanyard through a hole 28 in a tab 29 formed therein. The barrel 21 has an extent sufficient to enclose at least two miniature dry cell batteries 31 disposed in a series arrangement. The tail cap 22 has a region of external threading 32 which engages matching threads formed on the interior surface of the barrel 21. A sealing element 33, typically in the form of an 0-ring, is provided at the interface between the tail cap 22 and the barrel 21 to provide a watertight seal. A spring member 34 is disposed within the barrel 21 so as to make electrical contact with the tail cap 22 and a case electrode 35 of an adjacent battery 31. The spring member 34 also urges the batteries 31 in a direction indicated by an arrow 36. A center electrode 37 of the rearmost battery 31 is in contact with the case electrode of the forward battery 31. The center electrode 38 of the forward battery is urged into contact with a first conductor 39 mounted within a lower insulator receptacle 41. The lower insulator receptacle 41 also has affixed therein a side contact conductor 42. Both the center conductor 39 and the side contact conductor 42 pass through holes formed in the lower insulator receptacle in an axial direction, and both are adapted to frictionally receive and retain the terminal electrodes 43 and 44 of a miniature bi-pin lamp bulb 45. In Figure 3 there is illustrated a cylindrical sleeve 100 for location internally inside barrel 21 around the batteries 31. The forward end 101 of the sleeve 100 includes an internally directed circumferential lip 102. The action of the spring 34 is thus to cause contact of the conductor 42 with the lip 102 of the sleeve 100. The sleeve 100 is of a non-ferrous material such as brass and is nickel-plated. At the rear end, for location adjacent the tail cap 22 there are spaced slots 103 axially directed to form fingers 104 of a leaf spring. The tail cap 22 includes an inwardly directed annular slot 105 about the periphery of the tail cap 22 adjacent the second electrode of the battery 31. The annular slot 105 accommodates a portion of a spring member 106 so that the fingers 104 of the leaf spring engage the spring member 106 in annular slot 105. The lower insulator receptacle is urged in the direction indicated by the arrow 36, by the action of the spring 34, to move until it comes into contact with lip 102 formed on the end of the sleeve 100. At that point, electrical contact is made between the side contact conductor 42 and the lip 102 of the sleeve 100. An upper insulator receptacle 47 is disposed external to the forward end of the barrel 21. The upper insulator receptacle 47 has extensions that are configured to mate with the lower insulator receptacle 41 to maintain an appropriate spacing between opposing surfaces of the upper insulator receptacle 47 and the lower insulator receptacle 41. The lamp electrodes 44 and 43 of the lamp bulb 45 pass through the upper insulator receptacle 47 and into electrical contact with the center conductor 39 and the side contact conductor 42, respectively, while the casing of the lamp bulb 45 rests against the forward surface of the upper insulator receptacle 47. The head assembly 23 is installed external to the barrel 21 by screw threads 48 formed on an interior surface of the head 24 engaging with matching threads formed on the exterior surface of the barrel 21. A sealing 0-ring 49 is installed around the circumference of the barrel 21 adjacent the threads to provide a water-tight seal between the head assembly 23 and the barrel 21. A substantially parabolic reflector 51 is configured to be disposed within the forward end of the head 24, whereat it is rigidly held in place by the lens 26 which is in turn retained by the face cap 25 which is threadably engaged with threads 52 formed on the forward portion of the outer diameter of the head 24. An 0-ring 53 may be incorporated at the interface between the face cap 25 and the head 24 to provide a water-tight seal. When the head 24 is fully screwed onto the barrel 21 by means of the threads 48, the central portion of the reflector 51 surrounding a hole formed therein for passage of the lamp bulb 45, is forced against the forward surface of the upper insulator receptacle 47, urging it in a direction counter to that indicated by the arrow 36. The upper insulator receptacle 47 then pushes the lower insulator receptacle 41 in the same direction, thereby providing a space between the forwardmost surface of the lower insulator receptacle 41 and the lip 102 of the sleeve 100 on the forward end of the barrel 21. The side contact conductor 42 is thus separated from contact with the lip 102 on the sleeve 100. Appropriate rotation of the head 24 about the axis of the barrel 21 causes the head assembly 23 to move in the direction indicated by the arrow 36 through the engagement of the threads 48. Upon reaching the relative positions indicated in Figure 2 by the solid lines, the head assembly 23 has progressed a sufficient distance in the direction of the arrow 36 such that the reflector 51 has also moved a like distance, enabling the upper insulator receptacle 47 and the lower insulator receptacle 41 to be moved, by the urging of the spring 34 translating the batteries 31 in the direction of the arrow 36. In this position, the side contact conductor 42 has been brought into contact with the lip 102 of the sleeve 100 at the forward end of the barrel 21, which closes the electrical circuit. Further rotation of the head assembly 23 so as to cause further translation of the head assembly 23 in the direction indicated by the arrow 36 will result in the head assembly 23 reaching a position indicated by the ghost image of Figure 2, placing the face cap at the position 25' and the lens at the position indicated by 26', which in turn carries the reflector 51 to a position 51'. During this operation, the upper insulator receptacle 47 remains in a fixed position relative to the barrel 21. Thus the lamp bulb 45 also remains in a fixed position. The shifting of the reflector 51 relative to the lamp bulb 45 during this additional rotation of the head assembly 23 produces a relative shift in the position of the filament of the lamp bulb 45 with respect to a focus of the parabola of the reflector 51, thereby varying the dispersion of the light beam emanating from the lamp bulb 45 through the lens 26. In the embodiment of Figure 4, the head assembly 23 is shaped in a gradual taper 106 towards the tail cap 22 over an extent substantially greater than half the length of the head assembly 23. The taper 106 is substantially even and gradual. In the embodiment of Figure 5, the head assembly 23 is shaped in a gradual concave taper 107 towards the tail cap 22 over an extent substantially greater than half of the length of the head assembly 23. The taper 107 is a substantially evenly directed concave formation. Referring to the embodiments of Figures 4 and 5, the electrical circuit of the flashlight is described. Electrical energy is conducted from the rearmost battery 31 through its center contact 37, not shown in Figures 4 and 5, which is in contact with the case electrode of the forward battery 31. Electrical energy is then conducted from the forward battery 31 through its center electrode 38 to the center contact which is coupled to the lamp electrode 44. After passing through the lamp bulb 45, the electrical energy emerges through the lamp electrode 43 which is coupled to the side contact conductor 42. When the head assembly has been rotated about the threads 48 to the position illustrated in Figure 1, the side contact conductor 42 does not contact the lip 102 of the cylinder sleeve 100, thereby resulting in an open electrical circuit. When the head assembly 23 is rotated about the threads 48 to move forwardly away from the tail cap 22, the side contact conductor 42 is pressed against the lip 102 by the lower insulator receptacle 41 being urged in the direction of the arrow 36 by the spring 34. In this configuration, electrical energy flows from the side contact conductor 42 into the lip 102, through the sleeve 100, into spring 106 and into the tail cap 22. The spring 34 electrically couples the tail cap 22 to the case electrode 35 of the rearmost battery 31. By rotating the head assembly 23 about the threads 48 such that the head assembly 23 moves rearwardly in a direction counter to that indicated by the arrow 36, the head assembly 23 is restored to the position illustrated in Figure 1, thereby opening the electrical circuit and turning off the flashlight. By rotating the head assembly 23 about the threads 48 in a direction causing the head assembly 23 to translate forwardly relative to the barrel 21 in the direction of the arrow 36, the electrical circuit is closed as previously described, and the lamp bulb 45 is illuminated. Continued rotation of the head assembly 23 in that direction enables the head assembly 23 to be completely removed from the forward end of the flashlight 20. By placing the head assembly 23 upon a substantially horizontal surface such that the face cap 25 rests on the surface, the tail cap 22 of the flashlight 20 may be inserted into the head 24 to hold the barrel 21 in a substantially vertical alignment. Since the reflector 51 is located within the head assembly 23, the lamp bulb 45 emits a substantially spherical illumination, thereby providing an "ambient" light level. In a preferred embodiment, the barrel 21, the tail cap 22, the head 24, and the face cap 25, forming all of the exterior metal surfaces of the miniature flashlight 20 are manufactured from aircraft quality, heat-treated aluminum, which is anodized for corrosion resistance. The sealing 0-rings 33, 49, and 53 provide atmospheric sealing of the interior of the flashlight 20 to a depth of 61 metres (200 feet). All interior electrical contact surfaces are appropriately machined to provide efficient electrical conduction. With the nickel-plated sleeve 100 there is effective conductivity between the various nickel components of the electrical circuit without the exposure to corrosion by electrolysis which would otherwise occur with contact between different metals such as, for instance, aluminum and copper. The sleeve 100 avoids many of the manufacturing, degreasing and anodizing steps which would be otherwise necessary for the aluminum body and tail cap. The reflector 51 is a computer generated parabola which is vacuum aluminum metallized to ensure high precision optics. The threads 48 between the head 24 and the barrel 21 are machined such that revolution of the head assembly 23 through less than 1/4 turn will close the electrical circuit, turning the flash-light on. Additional turning will adjust the light beam from a "spot" to a "soft flood". A spare lamp bulb 62 may be provided In a cavity machined in the tail cap 22. While preferred embodiments of the invention have been described numerous modifications, alterations, alternative embodiments, and alternative materials may be contemplated by those skilled in the art and may be utilized in accomplishing the present invention. All such alternative embodiments are considered to be within the scope of the present invention as defined by the appended claims. In one such alternative, instead of a complete cylindrical internal sleeve 100, there could be a conductive element running down the inside of the barrel 21 with a suitable contact between a lip-type formation or contact at the forward end of the barrel 21 and the side contact conductor 42 47, and a contact with the tail cap 22.

Claims: A flashlight comprising: a barrel (21) for retaining at least one dry cell battery (31); a lamp bulb (45); a receptacle (41,47) within the barrel (21), between the forward end of the barrel and the battery receiving portion of the barrel, for holding the lamp bulb (45); the lamp bulb (45) being mounted such that lamp bulb electrodes (43,44) are mounted in the receptacle (41,47); a concave reflector (51); a substantially planar lens (26); a head assembly (23) for retaining the reflector (51) and the lens (45) located at the forward end of the barrel (21), said head assembly (23) being threaded to a surface at the forward end of the barrel (21) to be controllably axially translatable along the barrel (21) such that the relative positional relationship between the reflector (51) and the lamp bulb (45) may be varied, the reflector (51) having a central hole therethrough to enable passage of the light bulb (45), thereby varying the position of the reflector (51) relative to the lamp bulb (45) to change the focus of the light beam emanating from the lamp bulb (45) to vary the reflective dispersion of a light beam emanating through the lens (26) from said lamp bulb (45); means (39) for electrically coupling a first electrode of the battery (38) to the first electrode (44) of the lamp bulb; and a conductive element (100) within the barrel (21) for providing an electrical connection to a second electrode (35) of the battery (31) located adjacent the rear end of the barrel; wherein the head assembly (23) for retaining the reflector (51) and the lens (26) is movable in an axial direction relative to the barrel (21) to cause opening of an electrical coupling (102,42) of the second electrode (43) of the lamp bulb (45) with the conductive element (100), and the conductive element (100) has its forward end (101) provided with an annular lip (102) engageable by a contact (42) connected with the second electrode (43) of the lamp bulb (45) when the head assembly (23) is moved axially from the position in which the electrical coupling is open, characterised in that a tail cap (22) is engageable with the rear end of the barrel (21), the head assembly (23) is rearwardly movable to cause opening of the electrical coupling (102,42), the reflector (26) is substantially parabolic, the annular lip (102) is inwardly directed for engagement by the contact (42) when the head assembly is moved axially forwardly from the position in which the electrical coupling is open, and conductor elements (39,42) are provided in the receptacle (41,47) for electrically connecting the lamp bulb electrodes (43,44) with the battery electrodes (35,38), one such conductor element comprising the contact (42) engageable with said annular lip (102), and the other conductor element (39) being for connecting with the central battery electrode (38). A flashlight as claimed in claim 1, wherein the conductive element is a cylindrical sleeve (100) within the barrel (21) so that the battery (31) can be located in the sleeve. A flashlight as claimed in claim 2, wherein the rearward end of the sleeve (100) includes spaced axial slots (103) at spaced intervals to form fingers (104) of a leaf spring. A flashlight as claimed in claim 3, wherein the tail cap (22) includes an inwardly directed annular slot (105) about the periphery of the tail cap adjacent the second electrode (35) of the battery (31), said slot (105) being for accommodating a spring member (34) and wherein the leaf spring (104) engages the spring member (34) in the slot. A flashlight as claimed in claim 2, 3 or 4, wherein the sleeve (100) is of a non-ferrous material. A flashlight as claimed in claim 2, 3 or 4, wherein the sleeve (100) is a brass composition. A flashlight as claimed in claim 6, wherein the non-ferrous material is nickel plated. A flashlight as claimed in any preceding claim, wherein the lamp bulb is a bi-pin lamp bulb (45), each electrode of the lamp bulb being an elongated pin (43,44) extending from the lamp bulb (45). A flashlight as claimed in any preceding claim, wherein the head assembly (23) includes an outer surface (107) shaped in a gradual taper towards the rear end over an extent substantially greater than half the length of the head assembly. A flashlight as claimed in any one of claims 1 to 8, wherein the head assembly (23) includes an outer surface (107) shaped in a gradual concave taper towards the rear end over an extent substantially greater than half the length of the head assembly. A flashlight as claimed in any preceding claim, wherein the sleeve lip (102) is located adjacent the reflector (31), rearward axial translation of the head assembly (23) along the barrel (21) being adapted to cause the receptacle (41) to move from engagement with the lip (10) of the sleeve (100) and thereby separate the contact (42) from the lip (102) of the sleeve (100) to interrupt the electrical circuit of the flashlight. A flashlight as claimed in any preceding claim, wherein the tail cap (22) includes a spring member (34), said tail cap being threadably engageable with the barrel (21), and the spring member urging the dry cell battery (31) toward the forward end of the barrel. A flashlight as claimed in any preceding claim, wherein barrel (21) is adapted to receive at least two dry cell batteries (31) in a series electrical contact. A flashlight as claimed in any preceding claim, wherein the tail cap (22) is adapted to retain a spare lamp bulb (62). A flashlight as claimed in any preceding claim, wherein a sealing ring (49) is provided between the structure (23) and the barrel (21) to provide a seal during axial adjustment of the structure relative to the barrel (21). A flashlight as claimed in any preceding claim, wherein a sealing ring (33) is provided between the tail cap (22) and the barrel (21). A flashlight as claimed in any preceding claim, wherein said head assembly (23) removed from the barrel provides, lens down, a stand to receive tail end cap (22) to support the barrel (21) in an upright position, used as a table lamp.

Inventors: MAGLICA, ANTHONY
Applicants: MAG INSTRUMENT INC.
Application year: 1987
Main classification: F21L15
IPC codes: F21V23, F21V13, H01M6, F21Y101, F21L4, F21V14