US2353989A - Geometrical instrument - Google Patents

Description

' July 18,1944 1 J. H. D. BEAUCAGI; 2,353,989

GEOMETRICAL INSTRUMENT I Filed Dec. ll, 1941 2 Sheets-Sheet l l 3 ZI 2K4 5 eazooa/ge July 18, 1944- J. H. D. BEAUCAGE 2,353,989

GEOMETRICAL INSTRUMENT 'Filed Dec. 1'1, 1941 v 2 sheets-sheen:v

Patented July `18, 1944 UNITED STATES PATENT OFFICE e GEOMETRICAL 'INSTRUMENT 1 Joseph H. Beaucage, Pittsfield, Mass. Application December 11, 1941, serial No. 422,568

3 claims.

This invention relates to improvements in geometrical instruments of the type used for inscribing angles accurately and speedily, more particularly to a geometrical instrument of simple construction which can be used with the maximum of accuracy and speed in various kinds of work for plotting angles.

Still another aim of the invention is to provide an instrument by which angles of any desired degree can be quickly and easily plotted by means of which the legs of the angle may be measured accurately when laid out to desired length.

Other objects and advantages of the invention will hereinafter become more fully apparent from the following description of the drawings, which illustrate preferred embodiments thereof, and wherein:

Figure l is a plan View of one form of the geometrical instrument,

Figure 2 is a fragmentary plan view of the bottom or reverse side thereof,

Figure 3 is a fragmentary sectional View taken substantially along the plane of the line 3-3 in Figure 1,

Figure 4 is a top plan view of another form of the instrument,

l Figure 5 is a fragmentary bottom plan view of the same,

Figure 6 is a fragmentary sectional view taken Figure e,

, Figure '7 is a top plan view of still another form of the geometrical instrument,

Figure 8 is a fragmentary bottom plan View of the same, and i Figure 9 is a fragmentary sectional view taken substantially along the plane of the line 9-9'of Figure '7.

Referring more particularly to the drawings, wherein like reference characters designate like or corresponding parts throughout the different views, and referring particularly to Figures l to 3, I designates generally a geometrical instrument including a carpenters square attached a member-l2- The member i2 is in the shape of a quarter or quadrant of a circle. The member l2 is attached to one side of the carpenters square Il and at the apex thereof in any suitable manner, not shown, as'b-y means of cement, `lcrazing, welding or by suitable fastenings. The member I2 extends into the angle formed by the arms i3 of the square I! and its curved edge I4 extends between said arms and partly overlap them. The upper, or-exposed side substantially along theplane of the line 'E-S in 1:,

Il to which is ings and calibrations fory indicating angles, preferably, at 30, 45, 60, '75 and 90, and which can be measured in either direction, as seen at I5. It will be noted that the member I2`is slightly larger than the quadrant of a circle in order that the two end calibrations can be spaced from the straight edges lIE of the member I2 and said calibrations arel disposed over the arms I3 and are spaced outwardly from the inner longitudinal edges I'I thereof and are disposed substantially parallel to boththe inner and outer longitudinal edges of the arms I3. A plurality of elongated blades or ruler arms I8 are attached to the under side of the member I2,` in any suitable manner, and'project radially from its edge I4 with said arms being arranged so that their longitudinal axes form continuation of the calibrations indicating angles of 15, 30, 45, 60 and Obviously, the angles indicated by the calibrations I5 could be varied and the number of blades I8 and their relative positions could be correspondingly varied. As seen in Figure l, the upper faces of the blades or ruler arms I8 'are inscribed in inchesand'fractions thereof, beginning beyond 'the'edge I4, and the inner edges II are correspondingly inscribed, while the outer longitudinal edges of the square arms I3 are marked in inches andfractions thereof, from the apex of said outer edges. The member I2 is preferably provided with a screw i9 which extends upwardly therethrough and to'which is threadedly connectedv a knob 25, which is disposed onV the upper side of the member I2 and: which forms a handlev for the instrument I0;

The 'end calibrations I5y are spaced from the edges i6 a distance equal to the distances between the longitudinal edges of the blades I8 and the calibrations I5; which are disposed intermediate of said edges. Consequently, an angle, for'exam ple, of 15 can be accurately plotted by drawing a line along one of the edges Il -and the longitudinal edge which is remotel thereto'sof the blade I 8, which is adjacent to'saidaforementioned edge il. Likewise, angles of 15, 30, and so on, can be plotted by drawing 'lines'along' corresponding edges of the different blades I. Likewise, it will be readily obvious that by providing linear scales on the arms i3 and blades I8 that the legs of the angles plotted can be accurately measuredto desired lengths. The-linear scales of the edges I'l providek convenient rules for drawing lines to scale when the outer edges ofthe square II'are next to a straight edge or a T-square.

Another embodiment-of the geometrical inf of the member I2 is provided with degree mark- 55;' strument, designated generally il; fis, illustrated the under or back side of the protractor 22 by means of a pivot pin or rivet 29. The supporting member 28 is provided with an'upwardly oilset, arcuately shaped edge portion 30 which is disposed in substantially the same plane as the upper side of the protractor 22 andthe inner edge of which is in sliding engagement with the edge 21. Said upper surface of the portion 30 is provided with calibrations and degree markings which cooperate with the calibrations and degree markings ofk the protractor 22 to form a Vernier scale, as seen in Figure 4. A pair of arms 3| are suitably attached, at corresponding ends thereof, to the under side of the supporting member 28 and project radially therefromV and are disposed at right angles to one another. A plurality tof blades 32 are similarly attached, at corresponding ends thereof, toA the under side of the member 28 and project radially therefrom andare disposed between the arms 3| and are equally spaced from one another. The blades or arms 32 correspond to blades I8 and are similarly arranged relatively to each other, preferably at angles of apartand can be employed with the arms 3|, in the same manner as previously described, with reference to the instrument I8, for plotting angles. Likewise, the upper sides of the blades 32 are inscribed with linear scale markings, similar to the blades I8, and the'arms 3| are inscribed in the same manner.

The rivet 29 is disposed in the center of the curved edge 21 and at the center of the arcuately shaped offset portion 38 so that the member 28 can swing relatively to the protractor 22. The protractor 22 is provided with an arcuately shaped slot 33 and a screw or bolt 34 extends upwardly through the member 28 and loosely through the slot 33. The screw 34 carries a thumb nut 35 and a washer 36 preferably disposed between the thumb nut and the upper side of the protractor 22. It will thus be obvious that the member 28 can be swung relatively to the protractor 22 to position thearms 3| and 32 at various angles, as desired, after which the member 28 can be clamped to the protractor by tightening thumb nut 35. The ends of the portion 38 are adapted to abut against the edges 26 to form stops for limiting the swinging movement vof the member 28 and when one of said ends is disposed in engagement with its vedge 26 the longitudinal edges of the arm 3l. adjacent thereto, will be disposed parallel tothe straight edge 24. The zero calibrations of the protractor 22 are disposed parallel to the straight edge 24 so that said edge 24 can be employed with the arms 3| or blades 32 for measuring any angle from zero to one hundred eighty degrees, quickly and accurately. As seen in Figure 6, the underside of the base 23 extends to below the underside of the protractor 22 and is disposed in substantially the same plane as'the undersides of the arms 3| and 32. y

Another form of geometrical instrument, designated generally 31, is illustrated in Figures 7, 8 and 9 and includes a carpenters square 38 having linear scale markings, corresponding to the carpenters square Il. A substantially segment shaped member 39 is disposed on the square 38 and at the apex thereof and is suitably secured to an angular spacing strip 4) which, in turn, is suitably secured to the upper side of the square 38 for elevating the segments 39 above the surface of the upper side of the square 38. The length of the curved edge of the member 39, which is disposed in the angle formed by the arms of the square 38, is greater than an arc of and the upper side of the member 39, along its curved edge, is calibrated and provided with degree markings from zero to ninety degrees, as indicated at 4|. The Zero and 90 calibrations are spaced inwardly from the arms of the square 38 and are adapted to be disposed parallel to the longitudinal edges thereof. A supporting member 42, as best seen in Figure 8, which corresponds to the member 28, is pivotally connected to the underside of the segment 39 by means of a rivet 43. rThe rivet 43 is disposed at the center of the curved edges oi the members 38 and 42. The member 42 is provided with an upwardly offset portion 44, corresponding to portion 3|] and which slidably engages the curved edge of the segment 39 and which is provided with a vernier scale for cooperation with the degree markings and calibrations 4|. Six blades 45 are suitably secured, at corresponding ends thereof, to the underside of the member 42 and project radially from its curved edge. The blades 45 are spaced fifteen degrees apart and are provided on their upper sides with linear scales, corresponding to the blades I8. The segment 39 is provided with an arcuately shaped slot 46, as indicated in dotted lines in Figure '7, to receive a bolt 41 which carries a thumb nut 48 and washer 49, arranged in the same manner and for the same purpose as the bolt 34, nut 35 and washer 36. The length of the portion 44 is substantially fifteen degrees less than that of the exposed portion of the curved edge of the segment 39 so that the blades 45 can be swung to an arc of at least fifteen degrees to enable the instrument 31 to be adjusted for measuring any angle from zero to ninety degrees.

The operation and use of the instrument 31 is identical with that of the instrument I8 except that the blades 45 can be adjusted to lay out any angle up to ninety degrees, and a further description of the use of instrument 31 is therefore deemed unnecessary.

Various modifications and changes in the embodiment of the invention as disclosed, are contemplated and may obviously be resorted to, provided they fall within the spirit and scope of the invention as hereinafter defined by the appended claims, as only a preferred embodiment has been disclosed.

I claim as my invention:

1. A geometrical instrument comprising a segmental member having a curved edge extending more than 90 degrees and straight edge portions secured to the arms of a carpenters square, a plate disposed below and pivoted to said segmental member to move in the angle of such a square, said plate having a curved portion concentric with said curved edge to coact therewith in protractor relation, and blade means extending from said portion.

2. A geometrical instrument comprising a segmental member having a curved edge extending plate disposed below and pivoted to said segv mental member to move in the angle of such a square, said plate having a curved portion concentric with said curved edge to coact therewith in protractor relation, blade means extending from said portion, the ends of said plate being disposed for abutment against the arms of the carpenters square to limit movement in opposite directions.

3. A geometrical instrument comprising a segmental member having a curved edge extending more than 90 degrees and straight edge portions secured to the arms of a carpenters square, a plate disposed below and pivoted to said segmental member to move in the angle of such a square, said plate having a curved portion concentric with said curved edge to coact therewith in protractor relation, blade means extending from said portion, the ends of said plate being disposed for abutment against the arms of the carpenters square to limit movement in opposite directions, said plate portion being raised into approximately the plane of the segmental member, and the plate portion and segmental member at said curved edges having coacting calibrations.

JOSEPH H. D. BEAUCAGE.

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