Geometrical instruments – Indicator of direction of force traversing natural media – Level or plumb – terrestrial gravitation responsive
Reexamination Certificate
1999-12-02
2001-12-04
Hirshfeld, Andrew H. (Department: 2859)
Geometrical instruments
Indicator of direction of force traversing natural media
Level or plumb, terrestrial gravitation responsive
C033S297000, C033S373000, C033S528000, C033S529000
Reexamination Certificate
active
06324767
ABSTRACT:
CROSS REFERENCE TO RELATED APPLICATIONS
Not Applicable
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT
Not Applicable
BACKGROUND OF THE INVENTION
1. Field of the Invention This invention relates to levels and particularly levels mounted on cards.
2. Description of Related Art
The level is an ubiquitous tool. The standard form of level has changed little over hundreds of years. The basic feature of these levels is a liquid-filled tube that has a small air bubble in it. Because liquids always seek their own level, the bubble will be centered in the tube when the tube is held level. Levels are made in a variety of sizes, from a few inches to several feet long. Although these tools are extremely useful, they do have some minor drawbacks. In determining the level of small objects, or determining the level of flat objects on a wall, the standard levels are not easy to use. This, for electrical switch or outlet covers, it is difficult to get a proper level quickly. Leveling pictures or other items is also difficult.
BRIEF SUMMARY OF THE INVENTION
The present invention overcomes these difficulties. It eliminates the need for a bubble tube and the resultant frame. The level is a series of register marks that are printed on a flat card. The register marks are designed to fit square on the rectangular card. The primary marks are positioned at the two ends of the card. When looking at the register marks, the user can see any angular displacement between them. This angular displacement indicates an out of level condition. If the marks are viewed as being completely horizontal, the card is level. To use the device, simple stand the card up on the surface to be leveled. The angular displacement of the register marks instantly show whether the surface that the card is resting on is level. In this way, just about anything can be tested for level. The device can also be placed on walls or other objects to draw level lines or reference marks. It is also useful as a template for tracing or drawing straight lines for sewing or other activities.
Moreover, the card is easy to carry and use. It can be made the size of a typical credit card. Making the card from plastic makes it durable and portable.
The register marks can vary somewhat in placement and color. However, there are preferred placements of the marks. In addition, other reference points may be added to indicate angles or other useful measures, as desired.
REFERENCES:
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patent: 3744133 (1973-07-01), Fukushima et al.
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patent: 4549360 (1985-10-01), Allen
patent: 4879815 (1989-11-01), Vischer
patent: 5330179 (1994-07-01), Hampel
patent: 5813130 (1998-09-01), MacDowell
patent: 6032376 (2000-03-01), Shurtleff
Hirshfeld Andrew H.
Tavella Michael J.
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