Magnetic compass

Details Magnetic compass Magnetic compass

2001-12-13

2003-06-17

Bennett, G. Bradley (Department: 2859)

Geometrical instruments

Indicator of direction of force traversing natural media

Magnetic field responsive

C033S348000

Reexamination Certificate

active

06578277

ABSTRACT:

FIELD OF THE INVENTION
The present invention relates generally to a magnetic compass, and more particularly to the magnetic compass having an illuminating device therein and simple structure.
BACKGROUND OF THE INVENTION
As more people participate in outdoor leisure activities (such as mountain climbing and camping), there has been a proportionate increase in the demand for magnetic compasses. A conventional magnetic compass, such as that in U.S. Pat. No. 6,145,209, consists of numerous structural components and requires complicated and, furthermore, precise assembly to complete, with the objective of achieving reading accuracy through a biconvex lens that magnifies compass rose graduations. In addition to utilization by the average layman in leisure activities, such magnetic compasses are used for military applications and issued to soldiers.
Another type of magnetic compass, such as that in U.S. Design No. D369,982, has an aiming plate, scaling ruler, and other map-reading compass features for ascertaining position and distance.
Although the above two magnetic compasses are utilized by people for leisure activities, the magnetic compass disclosed by U.S. Pat. No. 6,145,209 has an inordinate number of structural components and is highly difficult to produce, it has a higher price that is not readily accepted by consumers. Although the magnetic compass taught by U.S. Design No. D369,982 has a scaling ruler and is capable of measuring actual distances on maps, most people do not understand how to use it and cannot take advantage of all the functions; the magnetic compass is also more expensive because it utilizes a large quantity of acrylic material. In addition, the magnetic compasses are of greater dimensions and weight, making them inconvenient to carry and, as a result, the magnetic compasses are not in widespread use among consumers.
Furthermore, to facilitate nighttime use, U.S. Pat. No. 6,145,209 discloses a lighting member situated on the bottom section of a mounting plate and since the light source is directed upward from the bottom section, light penetrates the compass rose disposed on the mounting plate to illuminate the graduations of the compass rose, thereby allowing the user to take readings. The drawback of such a design is that since the light source is projected from the bottom section of the compass rose, the projected light produces a diminutive bright spot that only illuminates a limited portion of the compass rose, which does not result in the most optimal illumination of the compass rose. Furthermore, since the illuminating device has numerous structural components and assembly is complicated, the production cost and retail price of the magnetic compass is significantly higher, a factor that inhibits consumer purchasing.
SUMMARY OF THE INVENTION
The primary objective of the present invention is to provide a magnetic compass, which has fewer structural components as well as a lower production cost and is easier to assemble.
Another objective of the invention herein to provide a magnetic compass having an illuminating device, which enhances the utility of the compass in dark.
To achieve the objectives above, the present invention provides a magnetic compass comprising a compass body having a housing and a magnetic needle situated inside the housing, an illuminant, a battery set, a base, a cover, a push button and a top lid. The base is provided with a base body having an internally formed recessed space, a battery compartment, and an illumination component chamber, wherein the compass body is situated within the recessed space. The battery compartment is disposed at one side of the recessed space and adapted to receive the battery set. The illumination component chamber is contiguous to the recessed space and the illuminant is positioned in the illumination component chamber such that its rays of emitted light are projected towards the peripheral walls of the compass body and, furthermore, the illuminant is connected to the battery set. In addition, an opening is formed at the top section of the base body that is contiguous with the recessed space and which is utilized to place the compass body into the recessed space. The opening of the base body is sealed by the cover. The cover is provided with a readout window and a push button hole corresponding in location to said compass body and said battery set. The push button is positioned in the battery compartment and, furthermore, its top portion protrudes through the push button hole of the cover. Pressing the push button establishes continuity between the battery set and the illuminant, enabling electrical current from the battery set to be supplied to the illuminant. The top lid is pivoted to one end of the base that folds down over the top surface of the base. In addition, the top lid is provided with a magnifying glass.


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patent: 5749150 (1998-05-01), McDermott
patent: 6145209 (2000-11-01), Chang et al.
patent: 6292137 (2001-09-01), Agnew et al.
patent: D462020 (2002-08-01), Chang

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