US3008236A

US3008236A - Angle trisector

Info

Publication number: US3008236A
Application number: US625891A
Authority: US
Inventors: Donald E Hanson
Original assignee: Individual
Current assignee: Individual
Priority date: 1956-12-03
Filing date: 1956-12-03
Publication date: 1961-11-14
Anticipated expiration: 1978-11-14

Description

D. E. HANSON ANGLE TRISECTOR Nov. 14, 1961 Filed Dec.

\f/AN GLE BISECTOR INVENTOR.

DONALD E. HANSON United States Patent Filed Dec. 3, 1956, Ser. No .625,891 1 Claim. (Cl. 33-1) The present invention relates generally to instruments and more particularly to an instrument capable of trisecting any angle.

The primary object of this invention is to provide an instrument capable of accurately trisecting any angle, which instrument eliminates all mathematical computations necessary in the conventional procedure for accomplishing this function, whereby the possibility of error and time and elfort normally required for tn'secting an angle would be greatly reduced.

Finally, it is an object to provide an instrument of the aforementioned character which is simple, safe and convenient to operate, and which will give generally eflicient and durable service.

With these objects definitely in view, along with other objects which will become evident as this description proceeds, this invention consists in the novel construction, combination and arrangement of elements and portions, as will be hereinafter fully described in the specific-ation, particularly pointed out in the claim, and illustrated in the drawing which forms a material part of this disclosure, and in which:

FIGURE 1 is the plan or top view of the instrument, the view being proposed as illustrating how the instrument is used;

FIGURE 2 is a side elevation of the instrument;

FIGURE 3 is a transverse sectional view of the portion of the instrument adjacent the sighting bore;

FIGURE 4 is a fragmentary sectional view of the pivot peg and adjacent parts; and

FIGURE 5 is a fragmentary sectional view of the pivot peg with the lockscrew.

Similar characters of reference indicate similar or iden tical elements and portions throughout the specification and throughout the views of the drawing.

Referring now to the drawing and to FIGURE 1 in particular my instrument includes the base arm 12 on one end of which is mounted a short cylinder 13 which provides the sighting bore 14. In the sighting bore 14, preferably adjacent what may be considered the bottom end thereof, there is mounted a transparent disc 15 with cross hairs 16 painted thereon or otherwise applied thereto. At the outer end of the base arm 12 there is provided a pivot peg 18 which is mounted for free rotary movement about its vertical axis by means of a large headed screw 17. In the end of the base arm 12 adjacent to the pivot peg 18, there is provided a sighting or register notch 20, said notch being aligned with sighting cross hairs 16 and the axis of the pivot peg 18. The cross hairs 16 are centered in the sighting bore 14, in order to accurately position the instrument for use.

The secondary arm 22 is mounted on the cylinder 13 and a second pivot peg 24 wtih a hand knob 26 on its upper end is pivotally mounted in the outer end portion of the said secondary arm. It is important to note that the axes of the pivot peg 18 and second pivot peg 24 are equally distant from the point of intersection of the sighting cross hairs 16. A reference notch 28 in the outer end of the secondary arm 22 is aligned with the sighting cross hairs 16 and the axis of the pivot peg 24. The pivot peg 18 and pivot peg 24 are identical in size and design except that pivot peg 24 is drilled and tapped to accommodate lockscrew 26.

The traverse bar 30 is of approximately three times the length of the base arm 12 and is recti-cylindrical with a is on the bisector line.

'ice

'2 pointer 32 Qnthe and adjacent t t e p o P 4- This Painter 32 m y be u itary with the bar 30, con it a dcWn-turnedterminal or a le g h s a t l y eq to the height of the traverse bar above the {bottom surface of the base leg 12. The traverse bar 30 is rigidly fixed to the pivot peg 24 by a set screw 34 or otherwise.

The portion 36 of the traverse bar 30, between the axis of the pivot peg 24 and the extremity of the pointer 32 has an effective or horizontal length equal to the distance fi'orn the center defined on the 'crosshairs 16 to the axis of either one of the

pivot pegs

18 or 24 which are equidistant from the cross hairs.

As illustrated, the arm 22 is pivoted on the cylinder 13 above the corresponding portion of the arm 12 and the arm 22 has the outer end portion 38 thereof offset downwardly to the level of the arm 12. In this way the instrument is adapted to lie flat on the surface whereon it is used.

The angle to be trisected is first bisected in the conventional manner, the bisector line being extended from the point of intersection of the angle sufiiciently to either side of the point of intersection to accommodate the instrument, as indicated in FIGURE 1. The instrument is then placed on the angle with the sighting cross hairs 16 coinciding with the point of intersection of the angle and the register notch 20 on the base leg 12 centered on one leg of the angle. The base arm 12 is held in this position and the hand knob 26 moved until the pointer 32 The entire instrument is now held in this position while a reference mark is made, indicating the location of the reference notch 28 in the secondary arm 22. The instrument is then removed and a trisector line 40 is drawn through the reference mark and the point of intersection of the angle, said line being extended beyond the point of intersection as at 42 in order to trisect the desired angle. If required, a second trisector line can be obtained by using the instrument with the register notch 20 aligned with the remaining leg 44 of the original angle.

Minor variation from the form disclosed herein may be resorted to without departure from the spirit and scope of this invention, and the said specification and drawing should be considered as illustrative rather than limiting.

I claim: Apparatus for trisecting an angle having an apex formed by two intersecting lines, and an angle-bisecting line, said apparatus comprising:

a single base arm having an indicating notch at one end thereof, said indicating notch being on the longitudinal axis of said base arm;

a single secondary arm having an indicating notch at one end thereof, said indicating notch being on the longitudinal axis of said secondary arm;

means for pivotally connecting together the other ends of said base arm and said secondary arm for relative pivotal movement about a first axis;

means, comprising a sighting bore having a reticule positioned above said first axis for positioning said first axis above the apex of said angle, whereby said reticule and first axis may be positioned above the apex of said angle, and said indicating notch of said base arm may be positioned in alignment with one said line of said angle to cause said base arm to line up along said line of said angle; a rigid traverse bar;

means for slidably and pivotably mounting said bar at a point of said base arm to pivot about a second References Cited in thefile 0t this patent UNITED STATES'PATENIS Steed Sept. 1, 1914 Galvin Aug. 2, 1927 Tihenko Nov. 7, 1933 Thibodeau Mar. 7, 1950 Hart et a1. June 16, 1953 FOREIGN PATENTS Germany Dec. 19', 1892 France Nov. 5, 1956 OTHER REFERENCES Page 34' of the Triseetion Problem, a book by Robert C. Yates, 1 942. (Copy in Div. 66.)