Geometrical instruments – Straightedge type – Square and fixed straightedge
Reexamination Certificate
1999-06-07
2002-06-25
Gibson, Randy W. (Department: 2841)
Geometrical instruments
Straightedge type
Square and fixed straightedge
C033S476000
Reexamination Certificate
active
06408529
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to carpentry tools, and in particular, to framing tools having integral measuring, marking and tabular information for enabling a worker to establish readily the material required and the layout lines for sizing lumber for use in framing and roof construction.
BACKGROUND OF THE INVENTION
Construction workers and carpenters use a wide variety of layout tools in the erection of various structures. To insure proper perpendicularity and angularity such that adjacent members are correctly aligned, framing squares and levels and gages are commonly employed. Most widely used is a carpentry framing square. The typical framing square is a single L-shaped piece of material having unequal legs having indicia at periodic markings to indicate incremental lengths. Levels may be integrated with such tools. While simple in construction, framing squares cannot be readily used to plumb studs or layout rafters for roofing. Moreover, framing squares are bulky, generally 12 inch by 24 inch or larger, and cannot be carried in an ordinary tool belt. Additionally, for roofing in particular, the size effectively prevents using the framing square during construction to check and verify the correctness of the layouts. While seeking to provide gage markings for additional carpentry tasks, angular indicia, compound cut markings and the like have been included in multi-purpose framing tools, this multiplicity of information is oftentimes confusing, unneeded or inherently provided by the construction tools.
One such approach is disclosed in U.S. Pat. No. 4,506,451 to Hiltz wherein an adjustable mechanical stop is provided to set an associated straight edge at a desired marking inclination. Liquid levels are incorporated for use in aligning 90° and 45° cuts. Discrete stops are required for each inclination. U.S. Pat. Nos. 4,745,689 to Hiltz, 4,922,621 to Maier, D197,309 to Schimmelman and D220,061 to Kerns disclose foldable selectively pivotal arm and straight edge-level tools that can be preset to replicate angular cuts. U.S. Pat. No. 5,669,149 to Meitzler and U.S. Pat. No. 4,394,801 to Thibodeaux disclose another foldable arm tools containing indicia, angular and numeric for establishing varying pitches and cut angles.
Another approach for marking pitch angles is disclosed in U.S. Pat. No. 3,456,353 to lams wherein two sliding pivot buttons that may be adjusted with respect to indicia to establish cutting angles. U.S. Pat. No. 4,574,492 to Miller discloses a layout tool provided with a number of slots and apertures containing configurations, slots and indicia for establishing angular cuts. U.S. Pat. No. 5,253,426 to Mosbrucker discloses a three-section layout square containing angular, pitch length and tabular indicia for use in making pitch and angle framing cuts. Similarly U.S. Pat. No. 5,727,325 to Mussell discloses a triangular multipurpose square that performs various straightedge and protractor orientations.
The foregoing, although in one way or another providing a basis for laying out commonly used construction angles and pitches, provide a multiplicity of superfluous information and tool orientation techniques for establishing the desired cutting lines. In addition to being needlessly complex for the average tradesman, awkward to handle, and cumbersome to carry conveniently on the tool belt around the job site, no information is contained thereon allowing the carpenter to select the proper length of material, conveniently layout the cutting lines, employ current measuring techniques and reference only the information necessary to make the base cuts required with modem construction tools. Additionally, for most construction applications, conventional layout equipment performs satisfactorily. However, in the roof framing field where varying pitches and runs are required in a compound roof design, a simple layout tool enabling the tradesman to select only the information needed to select the proper material and mark the cuts required for the ridge beam, base plate and overhang for convenient carrying on the tool belt around the job site has not yet been available.
SUMMARY OF THE INVENTION
The present invention overcomes the limitations and complexities of the prior art and fulfills the needs for a compact roof framing tool. The resultant multi-purpose roofing framing square is light weight, compact and easy to carry in a conventional tool belt holder, and contains all information necessary for the carpenter to select the proper length of material for a given roof section, mark all necessary cut lines, and saw the desired roofing configurations with a conventional circular saw.
More particularly, the multi-purpose roof framing square of the present invention provides a compact, lightweight, easy to use tool belt framing square containing all information and guide surfaces necessary for enabling the worker to select proper lumber lengths for rafters and beams, mark the correct pitch, establish load bearing notches, and create setoffs and overhangs. The framing square includes an elongated rectangular body having a standard 2× graduated width defined by graduated parallel sides and a length sufficient to mark common lumber widths. A crosspiece is provided at one end of the body orthogonal thereto and wider than the body. Accordingly, the framing square may be traversed along one edge of the lumber piece with the body perpendicular thereto thereby allowing the worker to make accurate markings for transverse cuts with indicia for marking common increments of the 2× dimensional lumber. Additionally, the outboard edge of the ruler is provided with a linear scale for marking incremental lengths. The inboard edge of the ruler is provided with angular indicia representing common roof pitches as measured from the pivot point between the cross piece and the ruler. By setting the pivot point at the desired marking for pitch cut, the ruler is rotated to align the pitch indicia with the longitudinal edge of the stock. The worker can then scribe a cutting line along the outboard edge of the ruler. Further, the framing square contains a table containing rafter lengths per width increment. Inasmuch as the typical worker customarily uses a calculator in normal activities, the length of the rafter for a particular run and pitch may be readily determined thereby quickly providing an indication of the minimum length required in each instance. Standard setoffs and overhangs may be easily added thereto in the calculation. Such length calculation may also be used to layout the “birdsmouth” notches from mounting the rafter to the top plate of the supporting wall. The above calculated rafter run is transcribed from the outboard tip of the rafter to the inboard edge thereof, a transverse line at the desired pitch transcribed therefrom, and a line transcribed at right angles thereto having a length for the support base conforming to applicable building codes. After marking and cutting one such rafter, the finished rafter may be used for making all similar rafter units.
It will thus be appreciated that with a single tool, lightweight and easy to carry in conventional tool pouches, the worker is provided with the information and tools required for laying out and cutting the various building roofing conditions experienced in the normal course of trade.
Accordingly, it is an object of the present invention to lightweight, easy to carry framing square containing a simplified layout format for marking and cutting lumber used in framing and roof.
Another object of the invention is a framing square for 2× dimensional lumber construction including scales and tables for establishing cutting lines at the desired lengths and angularity for conventional framing construction.
A further object of the invention is to provide a lightweight tool belt accessory for marking and cutting dimensional lumber to desired configurations in combination with tools ordinarily used by workers in the trade.
REFERENCES:
patent: 1179778 (1916-04-01), Turner
patent: 1196519 (1916-08-01), Cay
Gibson Randy W.
Mills Law Firm PLLC
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