US1770304A - Calculating device - Google Patents

Description

Filed Dec. 13, 1926 IIIIIII'IIIIIHIII-llf Vlllllllllillllllllll[will INVENTOR ATTORNEY Patented July s, 193.0

UNITED HARRY H. FERRIS, or Los ANGELES, CALIFORNIA GALCULATING Dnvicn Appiieetien mea December- 1s,v 1926. serial' ne. 154,553.

the invention further includes the followingY novel features and details of construction, to

be hereinafter more fully described, illustrated in the accompanying drawings and pointed ont in the appended claim.

In the drawings Figure 1 isv an elevation of the invention applied for use upon the. conventional form of square.

Figure 2 is a similar view of the calibrated clamping member.

Figure 3 is an end elevation thereof.

Figure 4 is an end elevation of an additional clamping member operablein conjunc tion with the remaining end of the calculating member.

Referring to the drawings in detail, wherein like characters of referencey denote corresponding parts, the reference character 10 indicates the conventional form of builders or carpenters steel square. Slidably mounted upon the vertical leg'of the square is aclamping member 11 including a set screw 12 extending within a slot 13 for engagement with f said vertical leg. An enlarged portion 14 is carried upon the inner side edge of the clamping member and adjacent the lowermost corner thereof and provided with a cut-out por-v tion 15, the lpurpose of which will be readily apparent.

A clamping member 16 ofa general configuration similar to that of the clamping member 11 is slidably mounted upon the horizontal leg of the square and adapted to be locked ina desired adjusted position after the manner of the clamping member 11.V An arcnate shaped scale 17 is carried upon one side edge of the clamping member 16.` An enlargedportion 18 carried by the upper left vhand corner of the clamping member 16 is provided with an opening 19 whose side walls flare oppositely and outwardly from a point substantially central of the opening.

" A calculating member consisting of an arm 20 marked olf in inches and twelfths, to

be subsequently referred to as feet and inches,

has the 'upper end thereof pivot-ally mounted within the cnt-out portion 15 of the enlarged portion 14 carried by the 'clamping member 11. The remaining end of the calculating de vice is disposed through the opening 19 and across the face of the'arcuate shaped scale 17. S'aid lscale is calibrated to indicate vthe rise in inches per foot run.`

, 1f the run were 111/2 feet andthe rise 7l/2, the respective clamping members would be disposed in registration with the inch markings upon the square. Said inch markings will now be considered as feet.v Extensions 21 carried by each of the .clamping members and ldisposed over the markings upon the square are divided into twelve divisions; each division representing one inch. l/Vhen the clamping members are disposed in the man-y nerv as illustrated in Figure 1 of the drawing the length of 'the comifnon rafter will be calculated upon'the arm 2O immediately behind the enlarge-d portion 18, the length Vbeing13feet'8 inches. The distance between the pivot lpoint for the iarm and the exposed portion of the arm extending therefrom is Aequivalent tothe vdistance from the center of the opening within which the set screw 22 is threaded within the enlarged portion 18V to the rear edge of the latter. rlfhe length of the common rafter will thus be indicated in feet between 13 and 14 and the portions of a e portion of the arm 2O extending across thev arcuate shaped scale 17 willcorrectly indicate the pitch of the rafter in the same calculation. The diculty as generally experienced in the calculation of the length of rafters and pitch thereof has been the reduction 5 of inches ordinarily calculated 'in sixteen sections to twelve. n the application of the present invention the inches are considered as feet and the sections of the feet are considered as twelfths. rEhe said tWelths are lo indicated upon the extensions 2l. A set screw 22 is carried by the enlarg-ed portion 18 of the clamping member 16 and adapted for biting engagement with the adjacent portion oil' the arm 2O to permit an operator to set l5 the instrument While calculating the length oi" the raiter and pitch.

Squares of the character described are generally provided with calculations upon the reverse sides thereof to give the pitch of a 20 rafter in degrees, namely, an eight inch rise on twelve would be three-fourths; the present invention overcomes the necessity of referring to the reverse side of the square which is often impossible when the square lies Hush with a plate and rafter.

The invention is susceptible of various changes in its form, proportions and minor details of construction, and the right is herein reserved to make suoli changes as properly all Within the scope of the appended claim.

Having thus described the invention what is claimed is A rafter measuring device adapted for use in conjunction with a square comprising clamping members provided with slotted portions adapted to permit sliding movement upon the legs of the square, set screws carried by the clamping members and projecting vithinthe slotted portions and being adapted o for engagement With the adjacent edges of the square legs to retain the clamping members in position for use, enlarged portions carried upon each of the clamping members, said enlarged portions having an opening therethrough Whose Walls are oppositely and outwardly flared, extensions carried by each of the clamping members having calibrations adapted to cooperate with the calibrations upon the square, an arm pivoted at one end o Within the single cut-out portion of one of the enlarged portions for sliding movement through the opening of the remaining enlarged portion and having graduations thereon, and one of the clamping members having Y d5 indicia thereon to cooperate with the adjacent edge of the arm to determine the pitch of a rafter Whose length is indicated upon the arm.

In testimony whereof I aiix my signature.

60 HARRY H. FERRrs.

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