US651057A - Steel square. - Google Patents

Description

Patented lun 5, |900.

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STEEL SQUARE. (Application med No. 1a, 1599,)

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M2292 25565 j 7% 7%7-44 m. MUJQW UNITED STATES PATENT OFFICE.

ARTEMAS ROBERTS, OF NORMAL, NEBRASKA.

STEEL SQUARE.

SPECIFICATION forming part Of Letters Patent No. 651,057, dated June 5, 1900.

Application led November 18, 1899. Serial No. 737,417. (No model.)

To all whom t may concern:

Be it known that I, ARTEMAs ROBERTS, a

citizen of the United States, residing at Normal, in the county of Lancaster and State of Nebraska, have invented new and useful Iinprovements in Steel Squares, of which the following is a specification.

My invention relates to certain im prove` ments in carpenters steel squares, the iinprovements'conternplated being,tirst,th esub stitution upon the blade of the steel square in place of certain figures or tables usually placed thereon of a conveniently-arranged rafter-table giving in duodecimals or feet, inches, and twelfths of an inch the length of rafters having a certain defined pitch or inclination and a given horizontal run, and, second, to give in connection with the raftertable the figures for the lengths, which, taken on the blade and tongue of the square, will give the bevels for the horizontal and vertical cuts for rafters having the given pitch or inclination. I `accomplish these objects in the manner illustrated in the accompanying drawing, which is a view of a portion of the blade of a carpenters steel square, showing the arrangement of my improved rafter-table with the figures giving the horizontal and vertical cuts for each pitch, as is more fully described below.

Upon the blade A A of a carpenter-s steel square, made in the usual forni, and the place usually occupied by a lumber-table I place a rafter table B B. This table consists of a number of parallel rulings having at the left end figures C, indicating a certain pitch of inclination, while along between the rulings and opposite the usual figures denoting the inches on the outside of the square are given the lengths in duodecimals or feet, inches, and t'welfths of an inch of rafters having the run in either feet or inches indicated by said figures and of the given pitch or inclination. In case the run of the rafters is taken in feet we call one inch on the square a f0ot, and the readings of the table will give the lengths correctly. In case the run is taken in inches the readings of the table will be in inches, twelfths, and one hundred and forty-fourths of an inch, and the latter may be neglected in most cases. lf the given run consists of feet and inches, the length of the rafter may be taken for the given number of feet and for the given number of inches, and the two added together will given the entire length.

To illustrate: Suppose the run of a rafter to be twenty-one feet and five inches (21 5") and the roof to have one-fourth (i) pitch. In the column indicating pitches we find Onefourth, and following the ruling We find under the figures 2l on the outside of the square the length Of a rafter havinga run of twenty-one feet, (2l,) Which is twenty-three feet five inches and nine-twelfths of an inch, and under the figure 5 We find the length five inches and seven-twelfths of an inch of a rafter of five inches run, and adding these we get the Whole length of the rafter, which is twenty-nine feet no inches and ten-tvvelfths of an inch, (29 0" 10.) In formulating this table I have adhered to the method in common use among carpenters of calling the proportion between the vertical height of the roof and the Width of the building or double the run of the rafter the pitch of the rafter. At the right of this table and opposite each of the ruled lines I place the figures, which, taken upon the blade and tongue of the square, give the bevels for the horizontal and vertical cuts of rafters having the designated pitch or inclination.

Having thus fully described my invention, what I claim is l., A carpenters steel square made in the usual form and having upon one side of the blade a table giving the lengths in duodecimals, or feet, inches and twelfths of an inch, of rafters having a certain defined pitch or inclination and a given horizontal run, the latter being indicated by the usual figures which indicate inches on the square substantially as described.

2. In combination With a carpenters steel square of the usual form a rafter-table, made as shown and described, in which the runs of rafters are indicated by the usual figures denoting inches on the square, While the rafter lengthsare given in feet, inches and twelfths, and having in connection therewith figures which taken upon the blade and tongue of the square will give the bevels for the horizontal and vertical cuts, substantially as set forth.

' AR'FEMAS ROBERTS.

Witnesses:

A. W. WOODS, MARY L. KINSLEY.

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