Electricity: measuring and testing – Fault detecting in electric circuits and of electric components – Combined with a flashlight
Reexamination Certificate
1998-12-07
2001-05-15
Metjahic, Safet (Department: 2858)
Electricity: measuring and testing
Fault detecting in electric circuits and of electric components
Combined with a flashlight
C324S507000
Reexamination Certificate
active
06232784
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to means of testing continuity of an electrical circuit and, more specifically, to apparatus for adapting a conventional flashlight for use as a continuity tester.
In many electrical applications, it is sometimes necessary or desirable to have a quick and easy means for testing circuit continuity, i.e., for determining whether there is an electrical path for current flow between two points. Many devices have been provided in the prior art for performing this function. Among such devices are those which include an incandescent bulb or other light-emitting means for providing a visual indication of presence or absence of circuit continuity in the apparatus or line under test. Often, the continuity tester includes a pair of wires terminating in alligator clips for attachment at the points between which continuity is to be tested. The prior art also includes means for modifying conventional flashlights to permit their use as circuit continuity testers.
The principal object of the present invention is to provide novel and improved means for adapting a conventional flashlight to act as a circuit continuity tester.
SUMMARY OF THE INVENTION
The apparatus of the invention is used in conjunction with a conventional hand-held flashlight, preferably of compact construction, having a detachable metal clip by which it may be attached to a pocket or other part of the clothing. The flashlight includes the usual hollow body portion wherein the battery or batteries are mounted. Upper and lower end caps are threaded to opposite ends of the body, the bulb being mounted in the upper end in conductive relation with the positive battery terminal. An electrically conducting spring is urged by the lower end cap, when the latter is fully engaged with the body, into conductive contact with the negative side of the batteries. Both end caps and the body, as well as the spring, are of conductive material and thus in electrical connection with the negative side of the batteries. An on-off switch is provided to selectively make or break the circuit connecting the bulb to the negative terminal of the batteries.
According to the present invention, an insulated electrical wire passes through an opening provided for such purpose in the lower end cap, placing one end of the wire inside and the other end outside the flashlight body. The end inside the body is soldered to an electrically conductive member, e.g., a rivet or a metal washer of appropriate size, and the end outside the body is soldered to the metal pocket clip which may be selectively placed in or removed from encircling relation to the flashlight body. The plate to which the inner end of the wire is soldered is placed between the spring and the negative side of the battery, being urged into conductive contact with the battery by the spring. In a first disclosed embodiment, a layer of insulating material is interposed between the metal plate and the spring, preferably by being coated upon or otherwise affixed to the surface of the plate opposing the spring. In a second disclosed embodiment, the normal flashlight spring is removed and replaced by a layer of somewhat resilient electrically insulating material which is compressed between the end cap and negative battery terminal; the head of a rivet is urged by the resilient layer into engagement with the negative battery terminal and the stem of the rivet extends into a through opening in the resilient layer where it contacts the end of the wire inside the flashlight body.
Thus, with the flashlight switch in the “on” position, the bulb is illuminated only when the metal pocket clip and metal exterior of the flashlight, i.e., the end caps or body, are placed in contact with two points between which electrical continuity exists. In this manner, the modified flashlight may be employed to test for circuit continuity between two points simply by placing the pocket clip in contact with one point and any other exterior surface in contact with the other point and observing whether or not the bulb illuminates.
The foregoing and other features of construction and operation of the invention will be more readily understood and fully appreciated from the following detailed description, taken in conjunction with the accompanying drawing.
REFERENCES:
patent: 3711768 (1973-01-01), Frazin
patent: 3753090 (1973-08-01), Tomek
patent: 3775677 (1973-11-01), Garrett et al.
patent: 4150330 (1979-04-01), Hudson et al.
patent: 5406207 (1995-04-01), Shershen
Hancock & Estabrook, LLP
McGuire George R.
Metjahic Safet
Nguyen Vincent Q.
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