Geometrical instruments – Straight-line light ray type – Alignment device
Reexamination Certificate
1999-01-28
2001-06-26
Bennett, G. Bradley (Department: 2859)
Geometrical instruments
Straight-line light ray type
Alignment device
C033S290000
Reexamination Certificate
active
06249983
ABSTRACT:
FIELD OF THE INVENTION
This invention relates generally to supports and, more particularly, to supports of the type having a platform for mounting a geometric instrument, e.g., a laser level.
BACKGROUND OF THE INVENTION
Builder's spirit levels have been in wide use for decades, perhaps centuries, for establishing reference lines and planes used during construction of roads, buildings, sidewalks and the like. A more recent innovation is a laser level which includes spirit vials for levelling and which also includes a laser light source for “spotting” a remote reference point upon a structure.
Equally common are the tripods upon which such levels are supported and examples of earlier tripods and levels are disclosed in U.S. Pat. No. 494,876 (Merrill), U.S. Pat. No. 753,149 (Lankford), U.S. Pat. No. 1,151,549 (Schade) and U.S. Pat. No. 2,308,206 (Poland). One of the features of the tripods shown in the Lankford and Schade patents is a levelling screw arrangement.
More recently developed tripods used by professional engineers and builders have a number of additional features not disclosed in the Merrill, Lankford, Schade and Poland patents. And while such features make the tripod easier to use and more accurate in use, the cost of such professional tripods has risen accordingly. In a modern, professional tripod, the levelling screw platform and related hardware is, itself, a rather costly component of the tripod.
A professional engineer or builder can justify the expense of such a tripod—after all, the tripod is an important tool of the profession and is subjected to use, perhaps hard use, daily or nearly so. But a homeowner/builder who might use a tripod only infrequently to, e.g., lay a sidewalk, build a shed or the like, has great difficulty justifying the expense of a professional-class tripod.
And that is not the only reason why a professional-class tripod might not be appropriate for the casual user. Another reason relates to ease (or, conversely, complexity) of operation. Modern professional-class tripods have a number of parts, including adjustment-related parts which, while contributing to the absolute accuracy required by a professional, may be baffling to the uninitiated user.
In view of the invention, it is neither necessary nor desirable for the casual homeowner/builder to employ a professional-quality tripod or, for that matter, to employ any tripod at all.
OBJECTS OF THE INVENTION
It is an object of the invention to provide a new levelling apparatus, often referred to in the trade as a “levelling base,” which overcomes some of the problems and shortcomings of the prior art.
Another object of the invention is to provide a new levelling apparatus which is easy for a casual homeowner/builder to use.
Another object of the invention is to provide a new levelling apparatus which is low in cost.
Still another object of the invention is to provide a new levelling apparatus which is compatible with commonly-available camera tripods.
Another object of the invention is to provide a new levelling apparatus which is useful alone, i.e., without a tripod of any type.
Another object of the invention is to provide a new levelling apparatus which is freely adjustable without the use of levelling screws or the like.
Yet another object of the invention is to provide a new levelling apparatus which, in a particular embodiment, provides three degrees of freedom of movement of a level mounted thereon. How these and other objects are accomplished will become apparent from the following descriptions and from the drawings.
SUMMARY OF THE INVENTION
The invention involves a levelling apparatus for a laser level, e.g., a combined spirit and laser level. The apparatus is low in cost and suitable for purchase and use by the home craftsman.
Such apparatus includes a substantially flat, disc-like base having a central axis generally perpendicular to such base. A cup-like, sphere-shaped socket component is mounted to the base and, more particularly, is mounted atop the base.
A sphere-shaped ball device, nominally a half-sphere, is received in the socket component for relative movement with respect thereto. The ball device, which supports the level, and the socket component are held in sliding contact with one another solely by the weight of the level and ball device bearing downwardly against the socket component. In this configuration, the levelling apparatus permits up-down and rotational movement of the level mounted thereon, as described in more detail below.
While the levelling apparatus is fully functional with the components described above, there is some risk of physical damage to the level mounted thereon. Whether or not the apparatus is supported only on its base or whether the base is supported atop a tripod, the ball device (to which the level is secured) can be freely removed from (or can easily fall out of) the socket component if the apparatus or its supporting tripod are inadvertently bumped or tipped over.
To the end of helping to prevent damage to the level, the highly preferred apparatus includes a retention mechanism having first and second locking members in overlapping relationship to one another, thereby retaining the ball device in the socket component. In one embodiment, the retention mechanism is spaced radially outwardly from the central axis and has a first locking member with a lip extending radially outwardly from the socket component. The second locking member includes a hook overlapping the lip and, most preferably, includes a plurality of hooks overlapping the lip.
In a specific embodiment, there are three hooks spaced 120° apart. Such hooks are somewhat flexible and extend outwardly and downwardly from the ball device, terminate below the lip and overlap the lip so that the socket component and the ball device cannot be separated from one another without flexing the hooks outwardly, thereby releasing them from the lip.
In another aspect of the invention, the socket component is fixed with respect to the base (by, e.g., sonic welding) so that the socket component and base cannot rotate or otherwise move with respect to one another. The socket component has an inner surface which is spherical over 360°. To state it another way, all points on the inner surface which are coincident with a plane perpendicular to the base-and-component central axis are at the same distance from such axis.
Similarly, the ball device includes an outer surface spherical over 360° and contacting the inner surface of the socket component, thereby permitting the ball device to pivot in any direction with respect to the socket component. To state that relationship another way, the ball device can be moved in such a way that a ball device concentric axis can circumscribe a circle on the plane mentioned above and can intersect such plane anywhere within the circle.
A specific embodiment of a ball device includes structure for aiding positional retention of the ball device and the laser level with respect to one another. In this embodiment, the ball device has an upper rim with a notch formed in it. The laser level includes a lower support or rail which is received in the notch with close fit.
There is some possibility that the embodiment of the apparatus which permits the ball device to pivot in any direction with respect to the socket component might be a bit unstable for some homeowner/users of the apparatus. In another embodiment, the apparatus includes a guide mechanism spaced radially outwardly from the central axis. Such guide mechanism has first and second guide members in overlapping relationship, thereby permitting only one degree of freedom of movement of the ball device with respect to the socket component.
In one, more-specific embodiment, the first guide member includes an arcuate groove in the socket component and the second guide member includes a tongue on the ball device and projecting into the groove. In another, similar embodiment (which might be termed an “inside out” version of the embodiment described immediately above), the second guide member includes a groove in the
Coel Joseph B.
Wright Randall J.
Bennett G. Bradley
Empire Level Mfg. Corp.
Jansson & Shupe & Munger Ltd.
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