Geometrical instruments – Indicator of direction of force traversing natural media – Level or plumb – terrestrial gravitation responsive
Reexamination Certificate
2004-01-09
2004-09-21
Fulton, Christopher W. (Department: 2859)
Geometrical instruments
Indicator of direction of force traversing natural media
Level or plumb, terrestrial gravitation responsive
C033S451000, C033S365000, C033S379000
Reexamination Certificate
active
06792686
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to levels and more specifically to the construction of the frame structure of levels and the interface of the various level inserts therewith.
BACKGROUND OF THE INVENTION AND SUMMARY OF THE INVENTION
The type of level herein contemplated is the type of level having an extruded thin wall frame structure having inserts therein such as a level indicating vial assembly.
Levels of this type typically utilized an extruded thin wall frame structure in the form of a solid I-beam cross-sectional configuration. This configuration had the advantage of presenting the user with a convenient shape to handle the level anywhere along the entire length of the frame structure irrespective of the working or operative surface orientation.
Another extruded thin wall structure which enjoys practical usage is the so-called box frame structure which is essentially four integral walls in a rectangular cross-sectional configuration. The advantage of the box structure is that it resists twisting loads along the longitudinal axis better than frame structures of solid I beam cross-sectional configuration. This is particularly true when considering that the formation of openings in the frame structure to accommodate the various inserts had a much more deleterious effect on the twisting resistance with the solid I beam cross-section than is the case with the centrally hollow rectangular cross-sectional configuration where the openings do not remove material extending along the central longitudinal axis. However, with a hollow rectangular cross-sectional configuration, the handling advantages of the I beam configuration were lost, requiring handling to be accomplished with a much more difficult pinching action between the spaced sides as compared with a hooking action under the crosspiece at each end of the thin central wall.
A different extruded thin wall frame construction is disclosed in U.S. Pat. No. 5,134,780, which purports to get a better measure of the advantages of both the commercial prior art frame structures and lesser measure of the disadvantages of both. The patent refers to the construction as being of hollow I beam configuration. The patent discloses two different embodiments, which differ from one another solely in the configuration of the working or operative walls.
In both embodiments, the structure disclosed provides one operative wall, which is planar, and a second spaced operative wall, which is formed with a V groove. In both cases, a pair of central walls is provided between the operative walls and perpendicular flanges extend outwardly from opposite ends of the central walls. The perpendicular flanges at the ends of the central walls adjacent planar operative wall are simply integral with perpendicular flanges extending from the planar operative wall. In the first embodiment shown in
FIG. 2
, a pair of convexly arcuate walls connects the perpendicular flanges at the ends of the central walls adjacent the V groove operative wall to a centrally located V wall. In the second embodiment shown in
FIG. 4
, the operative wall is parallel to the planar operative wall and is formed with a central V groove therein. The V groove operative wall includes flanges that connect integrally with the adjacent perpendicularly flanges. The present invention is based upon the underlying concept that the specific shapes disclosed in the '780 patent could be improved to further enhance the accrued advantages and diminish the disadvantages which are achieved in comparison with the commercial prior art structures.
An object of the present invention is to achieve the aforesaid improvement. In accordance with the principles of the present invention, this objective is achieved by providing a level comprising an extruded thin wall frame structure having an opening of I-shaped configuration from end to end thereof. The thin wall frame structure includes a pair of elongated operative walls each having a pair of transversely spaced inwardly turned flanges defining the width thereof and an exterior operative surface extending between the flanges thereof. The operative surfaces are planar and parallel. A pair of angular walls extend from each pair of spaced flanges in converging relation with one another and a pair of central walls are spaced apart in the direction of the width of the operative walls a distance less than the width of the operative walls and integrally interconnected between the pairs of angular walls extending from the flanges. The operative walls and the central walls having a plurality of wall openings therein.
An end member closes the opening at each end of the thin wall frame structure. Each end member has structure constructed and arranged to cooperate with the configuration of the thin wall frame structure to fixedly secure each end member in closing relation with respect to the associated end of the thin wall frame structure. A level indicating vial system has structure constructed and arranged to cooperate with the configuration of the thin wall frame structure to fixedly secure the level indicating vial system therein.
From the above it can be seen that the four angular walls cooperate with the other components of the combination to provide enhanced resistance to twisting loads about the longitudinal axis of the thin wall frame structure. The angular walls act in a similar manner to diagonal braces.
In accordance with another aspect of the present invention, the preferred embodiment of the above mentioned level further includes the indicating vial system further including a horizontal level indicating vial assembly within a wall opening in one of the operative walls, and a pair of vertical level vial assemblies within aligned wall openings adjacent the end members.
In accordance with another aspect of the present invention, the preferred embodiment of the above mentioned level further includes a hand hold assembly within longitudinally elongated aligned wall openings in the central walls. The hand hold assembly has structure constructed and arranged to cooperate with the configuration of the thin wall frame structure to fixedly secure the hand hold assembly within the elongated aligned central wall openings so as to present a handheld opening through the central walls.
In accordance with another aspect of the present invention, the preferred embodiment of the above mentioned level further includes a magnet assembly mounted in an operative position with respect to the thin wall frame structure within each of a plurality of longitudinally spaced openings therein. The openings have a width greater than the distance between the central walls.
It is contemplated herein that the various inserts could be further improved to cooperate with the thin wall frame structure having I beam cross-sectional configuration of the above mentioned level. In accordance to another aspect of the present invention, the above mentioned thin wall frame structure has a central opening in one of the operative walls and adjacent coextensive generally aligned openings in the central walls. The above mentioned level indicating vial system includes a horizontal level indicating vial assembly. The horizontal level indicating vial assembly has structure constructed and arranged to cooperate with the thin wall frame structure to fixedly secure the horizontal indicating vial assembly with respect to the openings so that a horizontal level indication can be viewed alternatively through the central opening in the one operative wall or either of the aligned openings in the central walls. The central opening has a width less than the width of the one operative wall so that the remaining portions of the one operative wall coextensive with the central opening and the associated coextensive portions of the adjacent flanges and angular walls provide structural continuity for the thin wall frame structure in the area of the openings.
In accordance to another aspect of the present invention, the above mentioned horizontal level indicating assembly further includes a horizonta
Baker Bernie W.
Krehel Gregg C.
Fulton Christopher W.
Reis Travis
The Stanley Works
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