Illumination – Self powered lamp – Cylindrical flashlight casing
Reexamination Certificate
1999-07-16
2001-04-24
O'Shea, Sandra (Department: 2875)
Illumination
Self powered lamp
Cylindrical flashlight casing
Reexamination Certificate
active
06220720
ABSTRACT:
SUMMARY OF THE INVENTION
This invention relates to flashlights, and particularly to improvements in water-resistant flashlights.
Conventional flashlights typically incorporate sliding switches in the sidewalls of their battery compartments. Such switches are subject to corrosion and wear, and have been notoriously unreliable. Moreover, because they are subject to leakage, they have been generally unsuitable for use in flashlights intended for underwater use.
These drawbacks of conventional flashlight switches have led to the use of rotatable head flashlights in which the battery compartment has no switch and is entirely water-tight, and in which a head, containing an assembly comprising a bulb, a parabolic reflector and a lens, is threaded onto the battery compartment. In rotatable head flashlights, switching is accomplished by rotation of the head relative to the battery compartment. Rotation of the head on the threads of the battery compartment causes the head to move axially, bringing contacts together, or separating them, depending on the direction of movement of the head. A water-tight seal is maintained between the head and the battery compartment, usually by an O-ring or other suitable sealing device. In some cases one of the contacts is a metal portion of the bulb itself. In others a battery terminal or a part of the battery case is used as one of the contacts. The use of portions of the bulb or portions of a battery or battery case as contacts has the advantage of reducing cost, but sometimes produces unreliable operation. Various other switching devices designed for cost reduction also give rise to a risk of unreliable operation. Still others utilize more complex head assemblies in the interest of reliability.
Reliability is, of course, an especially important consideration in underwater flashlight design, and an important object of this invention is to provide an inexpensive, water-resistant flashlight having a highly reliable switch.
The flashlight in accordance with the invention comprises a battery compartment having first and second opposite ends, and an internal space for containing an electrical energy source having a pair of terminals. The compartment is entirely closed except for a opening at one of the opposite ends, and has threads adjacent the opening. A head assembly, including a lens, has threads engaged with the threads of the battery compartment and provides a fluid-tight closure for the opening of the battery compartment. The operation of the threads moves the head assembly axially relative to the battery compartment as it is rotated. A bulb carrier assembly, supporting miniature incandescent bulb, is receivable through the opening of the battery compartment. The bulb carrier includes a reflector arranged to direct light generated by the light bulb through the lens. The bulb carrier is engageable by the head assembly and movable axially by the head assembly.
The bulb carrier has a pair of electrical terminals engageable with the terminals of the electrical energy source. The bulb carrier also has a normally open switch comprising at least two contacts one of which is movable relative to the bulb carrier. The contacts of the switch are carried by the bulb carrier, and conductors provide a series circuit through the bulb, the switch and the pair of electrical terminals. The battery compartment includes a surface engageable with the movable contact of the normally open switch, and positioned to urge the movable contact in a direction to close the series circuit when the head assembly moves the bulb carrier axially in a first direction relative to the battery compartment.
In a preferred embodiment of the invention, the carrier includes a printed circuit board on which the conductors are printed, and on which both electrical terminals, and the contacts of the switch, are mounted.
The board optionally has a socket mounted on it, removably receiving, and providing electrical connections to, the bulb. In the preferred embodiment, the switch includes three contacts, the movable contact being a resilient, bridge-like element overlying both of the other contacts. The surface engageable with the resilient element is preferably a molded shelf formed on the interior wall of the battery compartment.
Preferably, a spring in the battery compartment urges an electrical energy source in the battery compartment in a direction such that the terminals of the electrical energy source are continuously held in contact with the pair of electrical terminals of the bulb carrier. The electrical energy source preferably comprises a pair of cells disposed in side-by-side relationship and connected electrically in series.
Interengaging elements on the battery compartment and the bulb carrier may be provided to prevent rotation of the bulb carrier with the head assembly while permitting axial movement of the bulb carrier relative to the battery compartment.
Other objects, details and advantages of the invention will be apparent from the following detailed description when read in conjunction with the drawings.
REFERENCES:
patent: 4450508 (1984-05-01), Carley
patent: 4999750 (1991-03-01), Gammache
patent: 5213408 (1993-05-01), Shiau
patent: 5383104 (1995-01-01), Hou
patent: 5839821 (1998-11-01), LeZotte
patent: 6045236 (2000-04-01), Cheng et al.
patent: 6050699 (2000-04-01), Bouffay et al.
Howson & Howson
Neils Peggy C
O'Shea Sandra
Princeton Tectonics, Inc.
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