Geometrical instruments – Miscellaneous – Light direction
Reexamination Certificate
1999-07-26
2001-08-14
Bennett, G. Bradley (Department: 2859)
Geometrical instruments
Miscellaneous
Light direction
C033S481000, C033S474000
Reexamination Certificate
active
06272758
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to the field of hand tools for construction workers and more specifically to hand tools used by steelworkers and steel fabricators to lay out bolt and weld patterns and to fit up structural steel members.
BACKGROUND
Structural steel members are widely used in the construction of buildings, bridges, billboards, signs, piers, foundations, retaining walls and similar structures. These structures are typically built with a steel fine to which floors, walls, panels and other elements are connected. These steel frames are typically constructed from structural steel members which are made with standard cross-sectional shapes which are especially suited for particular applications.
One cross-sectional shape that is particularly common is the ubiquitous “I-beam.” The “I” shaped cross-section of the I-beam has a particularly high moment of inertia for its size and weight making it extremely useful as a beam for carrying loads. This shape also makes it resistant to buckling when used as a column or brace. Several variations of the I-beam have become standard in the industry and are shown in FIG.
1
. The “W” shapes or wide-flange sections
2
, the “M” shapes or miscellaneous flange sections
4
, the “S” shapes or standard flange sections
6
and the “HP” shapes or bearing pile sections
8
all have the characteristic “I” shape with its protruding flanges
16
and interior web
18
. Structural channels
10
and angles
9
also have a shape with protruding flanges
16
, however, on channel sections
10
and angles
9
the flanges protrude from only one side of the web. Structural “T ” shapes
12
also have protruding flanges as do numerous other composite shapes
14
which may be fabricated for special purposes.
Connections between structural steel members are typically made using multiple bolts which are spaced apart in specific patterns with precise spacing dimensions or using welds along with gussets and brackets to form the connection. Connections of structural steel members may be simple connections, as shown in
FIGS. 2A through 2D
where shear forces are transferred, but little bending moment is transferred in the connection or they may be more complicated moment resisting connections, as shown in
FIGS. 2E and 2F
where substantial bending moment and shear forces are transferred in the connection. Both types of connections typically require numerous bolts
20
arranged in patterns
22
with standard spacing requirements.
The fabrication of these bolted connections begins in the shop where beams, columns and other members are cut, welded, drilled and otherwise prepared for assembly on a construction site. Often clips, gussets, brackets, stiffeners, plates and other elements are cut and welded or bolted to one member and drilled for assembly to an accompanying member with bolts which are inserted on site. This construction fabrication requires precise measurement of bolt and other element locations so that field assembly will flow smoothly without interruption. Accordingly, bolt and weld locations must be laid out with precision, accuracy and efficiency.
While bolt locations and patterns vary for different connections, grades of steel and member shapes, the prevalence of certain grades of steel and certain structural shapes makes some bolt spacing patterns especially common. Bolt spacings which are commonly found in structural steel connections are 3″ and 5½″ . In laying out these patterns, measurements must often be made from the top of the top flange on the beam to a point on the beam web. This requires a steelworker to measure around the top flange and place an accurate mark on the web of the steel member. This requires several steps and multiple tools using conventional layout tools. A tool which allows this measurement to be performed in one step can drastically increase productivity and significantly reduce the possibility of error.
Large structural steel members can be extremely expensive and an incorrectly placed bolt pattern can damage or completely ruin one of these members causing extensive financial loss. Furthermore, a mistake may not be discovered until the steel member is raised to the top of a high-rise building project with a crane. At this point many man-hours may have been wasted in transporting and placing the steel member only to discover that the member is defectively fabricated. This type of mistake can be extremely costly in wasted man-hours and material. Consequently, steelworkers are typically highly skilled workers who gain extensive experience before receiving responsibility for connection layout.
Due to the heightened responsibility and the highly skilled nature of the job, steel workers typically receive higher wages than the majority of construction workers. A steelworker who can work quickly and efficiently is, therefore, a tremendous asset. Correspondingly, a tool which can improve steelworker speed and efficiency and increase accuracy and precision is also a tremendous asset.
SUMMARY AND OBJECTS OF THE INVENTION
Preferred embodiments of the present invention comprise a tool that is especially useful in laying out bolt and weld patterns on flanged structural steel members. The present invention is also useful in measuring and laying out cuts and connections on structural steel tubing, pipe and other non-flanged members.
Preferred embodiments of the present invention comprise a tool with parallel arms which can be used to reach around the flange of a steel member and measure directly to a point on the member's web. The edges of these parallel arms are spaced apart at distances which are commonly used for bolt spacing so that standard pattern measurements can be easily measured without clumsy manipulation of adjustable squares and tapes. The result is a measurement which is not only more accurate, but one that is completed in a fraction of the time required for completion with known tools.
Preferred embodiments of the present invention also comprise an offset design which forms somewhat of a “Z” shape and which allows the invention to be used as a conventional square as well as a special purpose square which can be used on corners with fillet welds, inside radii or other obstructions. The offset design also allows the present invention to be used to mark perpendicular lines on pipes and other round members. Additionally, the offset design's “Z” shape allows the present invention to be self-supporting when placed on its edge so that it may be used for squaring and fitting-up a connection while affording the user a “hands-free” situation.
Preferred embodiments of the present invention also comprise novel extensions which give the present invention a variable length to increase its utility and accuracy for certain measurements. Further, the present invention is made in a variety of sizes to accommodate different ranges of steel member size.
An adjustable, locking cross bar is also incorporated into preferred embodiments of the present invention and allows the present invention to be used directly as a level, to locate the top of a horizontal pipe and other uses.
The present invention allows for the speedy and accurate accomplishment of myriad measurements not previously measurable with any single known tool.
Accordingly, it is an object of preferred embodiments of the present invention to provide a method and apparatus for direct and precise measurement around flanges and other protrusions on steel members.
It is another object of preferred embodiments of the present invention to provide a method and apparatus for making a perpendicular measurement from an inside corner which has a radius or a fillet weld.
It is an additional object of preferred embodiments of the present invention to provide a method and apparatus for locating the top of a horizontal pipe or round object.
A further object of preferred embodiments of the present invention is to provide a method and apparatus for simplifying the layout of standard bolt patterns.
An additional object of preferred emb
Bennett G. Bradley
Kirton & McConkie
Krieger Michael F.
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