US1242467A - Geometrical instrument. - Google Patents

Description

J. R. PEIRCE.

GEOMETRICAL INSTRUMENT.

APPL|CATION FILED AUG.26. I916,

Patented Oct. 9,1917.

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JOHN B. rnmon, or MONT CLARE, PENNSYLVANIA. 1

GEOIVIETRICAL memmem.

Specification of Letterslatent.

Patented Get. 9, 19 17 Application filed August 26, 1916. Serial No. 117,057.

To all whom it may concern:

Be it known that I, JOHN R. Pnrnon, a citizen of the United States of America, residing at Mont Clare, in the county of Montgomery and State of Pennsylvania, have invented new and useful Improvements in Geometrical Instruments, of which the following is a specification.

My present invention relates to an improved geometrical instrument of that type employing a square and pivoted blade.

The primary object of the invention is to provide an instrument of this character especially adapted for use in beveling rafters, joists, etc., and also adapted for use by draftsmen in laying ofi work.

The invention consists in certain novel combinations and arrangements of parts as will be hereinafter specified and claimed.

In the accompanying drawings I have illustrated one complete example of the physical embodiment of my invention constructed according to the best mode I have so far devised for the practical application of the principles of my invention.

Figure 1 is a plan view of a complete instrument embodying the present invention.

Fig. 2 is an edge View of the instrument of Fig. 1. v

Fig. 3 is an enlarged sectional view on line 3-3, Fig. 1.

Fig. at is an enlarged sectional view on line 4-4:, Fig. 1, showing only the body of the instrument, the pivoted blade being omitted for convenience of illustration.

In the preferred form of my invention as shown in the drawings, I have illustrated a square 1 which may be of wood, metal, celluloid, or any other suitable material, and is provided with right angled edges 2 and 3. The square is provided with an additional pair of right angled edges 4 and 5, which are parallel with the edges 2 and 3, respectively so that a rectangular portion is provided in the square, with the edges 4 and 5 j of precise and similar length. This formation provides for the extended angular portions 6 and 7 of the square, and of course these portions 6 and 7 are to be used for the purpose of drawing perpendicular lines. The edges a and 5, of course, may also be used for drawing parallel on-perpendicular provided with a fixed screw or threaded pin 11, which is adapted to swing in an arcuate slot 12 which is struck from the pivot point 10 as a center, and by means of the thumb nut 13 the blade may befixed in adjusted position. i

The outer edges of the body of the instrument are beveled, as -is also the outer portion of the bevel 9, for convenience in use. 'The edge 9 of the blade, it will be noted, radiates from the center of the pivot pin 10. and this edge is adapted to be used in conjunction with the graduated spaces on the two scales l and 5.

In use, if it is desired to secure a bevel of nine inches to one quarter inch, the bevel 9 is moved to the position indicated in Fig. 1, and the blade is locked in its adjusted position by the use of the thumb nut 13, and the work may be properly laid out as desired.

From the above description taken in connection with my drawings, it will be seen that the device possesses efficiency, simplicity. and that it is comparatively inexpensive'in first cost, and not liable to become disarranged, but may be manipulated with accuracy and despatch.

WVhat I claim is:

1. A geometrical instrument of the square type comprising an integral body having a pair of edges at right angles to each other,

and a second pair of shorter edges arranged v perpendicularly to these first mentioned edges, so that the edges of the first pair extend beyond the adjacent edges of the second, said second mentioned edges having scales thereon, and a blade pivoted to the body and coacting with said scales.

2. A geometrical instrument ot the square type having a pair of edges at right angles said body having an urcuate slot, a threaded to each other, and a second pair of edges pin in the blade adapted to move in the slot, Derpendieular to these first mentioned edges and a thumb nut on the pin. adapted to hold provided with scales, the body of the instruthe blade in adjusted position.

5 ment being recessed at its underside, a blade In testimony whereof I my signature.

pivoted in the body of the instrument and adapted to swing in the recessed portion, JOHN R. PEIRGE.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patenm Washington, 11, 6).

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