US2719359A - Protractor - Google Patents

Description

W. D. WEBBER Oct. 4, 1955 PROTRACTOR 2 Sheets-Sheet l @ZM T m W@ Oct. 4, 1955 w. D. WEBBER 2,719,359

PROTRACTOR Filed Oct. 15, 1954 2 Sheets-Sheet 2 I N VEN TGR.

ATTD RN EYE United States Patent C PROTRACTOR William D. Webber, Chicago, Ill.

Application October 15, 1954, Serial No. 462,553

8 Claims. (Cl. 33-1) This invention relates to a measuring instrument, and more particularly to a protractor.

This invention is an improvement over the protractor shown and described in my Patent No. 2,602,228.

The object of the invention is to provide a yprotractor which will enable the user to not only accurately determine any angle of any degree, but also to conveniently determine any fractional part of a degree.

Another object of the invention is to provide a protractor which can be used to determine any degree and any fractional part of a degree down to the minute and wherein an angle can be determined even from a course the bearings of which are unknown.

A further object of lthe invention is to lprovide a protractor which is extremely simple and inexpensive to manufacture.

Other objects and advantages will be apparent during the course of the following description.

ln the accompanying drawings, forming a part of this application, and in which like numerals are used to designate like parts throughout the same:

Figure l is a top plan View of the protractor, constructed according7 to the present invention, and with parts broken away and in section.

Figure 2 is a cross sectional View taken through the protractor of Figure 1.

Figure 3 is a fragmentary plan view yof the base.

Figure 4 is an enlarged fragmentary sectional view showing certain constructional details of the protractor.

Figure 5 is a sectional view showing the relationship between the base, disc'and ring.

Figure 6 is a plan view of a modified protractor, with parts broken away and in section.

Figure 7 is a cross sectional view taken through the protractor of Figure 6, and with the parts disassembled.

Figure 8 is a cross sectional View taken through the protractor of Figure 6, and showing the parts in their assembled position.

Figure 9 is a fragmentary sectional View showing a modified protractor wherein a thumb screw is used for maintaining the parts immobile in their adjusted positions.

Referring in detail to the drawings, the numeral 10 designates a ring which can be made of any suitable material such as a transparent plastic, and the lower surface of the ring 1t) is provided with a circular recess or cutout i1. Snugly seated in the recess 11 is a circular base 12 which is also made of transparent material, and rotatably connected to the base 12 is a circular disc 14.

A suitable securing element such as a rivet 15 serves to rotatably connect the disc 14 and base 12 together, Figures 2 and 4. The disc 14 is provided with a plurality of large cutouts or openings 16 which are adapted to register with openings 17 in the base 12. These openings 16 and 17 are adapted to be engaged by the users fingers when the protraetor is to be lifted up olf of a at surface. The straight edges of the large cutouts 16 and 17 which parallel the sides of the table 32 are beveled or tapered on 23,719,359 Patented Oct. 4,l 1955 the disc 14 and on the base 12, as indicated by broken lines in Figure 1. The outer periph/:ry of the ring 10 is beveled or tapered as at 18 whereby the outer periphery of the ring 10 terminates in a sharp edge for increasing the accuracy with which the protractor can be read or used. The ring 10 is provided with a circular cutout or opening 20 in which is rotatably mounted the inner disc 14. The inner edge of the ring 10 is beveled or tapered as at 19, Figure 5, and the adjacent outer edge of the disc 14 is also beveled or tapered as at 21. Thus, it will be seen that these tapered surfaces 19 and 21 cooperate whereby with the parts assembled as shown in Figure 2, the ring 10 is prevented from accidentally moving out of its proper position.

The base 12 is divided into four quadrants 22, and two of these quadrants have scales or graduations thereon, these graduations being indicated by the numeral 23, Figures l and 3, The ring 10 is also divided into four quadrants of degrees each and the dividing lines of the quadrants on the ring 10 are at the points indicated by the numerals 24, 25, 26 and 27. The ring 10 is further provided with four rows or sets of graduations or markings on one half thereof, and these four rows of scales or markings are designated by the numerals 28, 29, 30 and 31, Figure l. A reference table 32 may be imprinted on the disc 14 or arranged thereon in any suitable manner.

Referring to Figures 6, 7 and 8 of the drawing there is shown a modified protractor wherein the numeral 33 designates a ring which can be made of a transparent material. The lower surface of the ring 33 is provided with a recess 40, and the ring 33 is provided with cutouts 34 which define a rib or crossbar 35. The crossbar 35 has an opening 36 through which is adapted to be projected a suitable securing element such as a rivet 37, and the rivet 37 also extends through a registering opening 38 in a base 39. The base 39 is snugly and rotatably seated in the recess 40 in the lower surface of the `ring 33. After the rivet 37 has been inserted through the openings 38 and 36, it may be peened over as shown in Figure 8 so as to maintain the ring 33 and base 39 connected together.

The base 39 may have on its upper surface the reference table 32, and the base 39 is divided into four quadrants 22 in the same manner as the previously described base 12. Also, two of the quadrants 22 have graduations 23 thereon. Also, the ring 33 is divided into four quadrants and the dividing lines between the four quadrants on the ring 33 are again indicated by the numerals 24, 25, 26 and 27. Furthermore, the ring 33 has the four sets of markings or graduations 28, 29, 30 and 31 as does the previously described ring 10.

Referring to Figure 9 of the drawing, there is shown a further modification wherein instead of using the rivet 37, a screw 41 may be extended through the openings 38 and 36 for maintaining the parts connected together. A nut 42 is arranged in threaded engagement with the screw 41, so that by tightening the nut 42 on the screw 41, the ring 33 and base 39 can be maintained immobile with respect to each other after they have been adjusted to a desired position.

From the foregoing it is apparent that there has been provided a protractor which is an improvement over the protractor shown and described in my Patent No. 2,602,228. The precision instrument of the present invention will permit the user to not only determine an angle of any degree but will also permit the user to conveniently determine any fractional part of a degree. The instrument is simple to make, accurate to use, easy to operate and inexpensive to manufacture. The instrument shown in Figures l through 5 is composed of three main parts that is the ring 10, base 12 and disc 14. The ring 10 can be rotated and is held in place by means of the interengaging surfaces 21 and 19. However, the disc 14 and base 12 can be laminated together or else they can be rigidly connected together by means of the eyelet or rivet 15.

The graduations 23 on the base 12 are computed by dividing seventy-six degrees (76) into fifteen (15) equal parts. The graduations on the base 12 are thus spaced five degrees and four minutes (05 04') apart. These graduations read from Zero to the right and to the left and are as follows: Five degrees and four minutes 04'); ten degrees and eight minutes (10 08'); lifteen degrees and twelve minutes (15 12'); twenty degrees and sixteen minutes 16'); twenty-five degrees and twenty minutes 20'); thirty degrees and twentyfour minutes 24'); thirty-five degrees and twentyeight minutes 28'); forty degrees and thirty-two minutes 32'); forty-five degrees and thirty-six minutes 36'); fifty degrees and forty minutes (50 40'); fifty-five degrees and forty-four minutes 44'); sixty degrees and forty-eight minutes 48'); sixty-five degrees and fifty-two minutes 52'); seventy degrees and fifty-six minutes 56'); and seventy-five degrees and sixty minutes 60').

The graduations 28, 29, 30 and 31 on the ring 10 or on the ring 33 are in degrees. Thus, by rotating the ring 10, in either direction for any given number of degrees, the degree graduations on the ring 10 will always be relatively in the same location in relation to the graduations on the base 12. It follows therefore that if the ring 10 or the ring 33 is moved to the desired number of degrees, and an additional fractional part of a degree is desired, the ring 10 can be moved in the same direction until the degree graduation on the ring 10 near the desired minute graduation 23 on the base 12 is registered thereon. Therefore, with a protractor of this type, it is posible to not only determine any desired degree, but in addition, to determine any fractional part of a degree to the extent of four minutes (04') or any multiple thereof.

The ring and base are each divided into four quadrants of ninety degrees each. The dividing lines between the quadrants on the rings are at the points 24, 25, 26 and 27. On each side of these points on the ring 10, there are graduations which are spaced fifteen minutes (15') apart, viz: Fifteen minutes 15'); thirty minutes (30'), and forty-five minutes (45'), for convenience in determining any of those fractional parts of a degree.

Due to the fact that the protractor can be made of any practical size, the combination of the degrees on the ring 10 and the fractional parts of the degrees on the base 12 plus the fifteen minute 15') graduations at points 24, 25, 26 and 27, on the ring 10 make it possible for the user of the protractor to determine any degree and any fractional part 0f a degree down to the minute, as evidenced by the reference table 32. The table 32 is included on the protractor as a ready reference.

The openings 16 and 17 which register with each other facilitate the picking up and handling of the protractor.

In Figures 6 through 9, there is shown a protractor which is used in the same manner as the previously described protractor of Figures l through 5. However, in Figures 6 through 9 the rotary wheel or ring 33 has a crossbar 35 which extends through its center and is an integral part thereof. The crossbar 35 is pivotally connected to the base 39 by means of a shaft or rivet 37. As shown in Figure 9 a thumb screw 41 and nut 42 can be used to lock the ring 33 in any desired angular position when desired.

The protractors of the present invention are made of transparent material such as of suitable plastic. With the present invention any angle can be determined even from a course the bearings of which are unknown. Thus, courses do not always have reference to compass bearings and it is not always necessary to have the point zero of the protractor set at true north. Courses are not always necessarily described by compass bearings in relation to magnetic north or true north. Angles can be determined from courses without relation to compass bearings and the present invention goes beyond the scope of the prior art in that not only any degree but any fractional part thereof can be determined. Also, the protractor can be used without reference to compass bearings.

The table 32 is used for the purpose of eliminating the necessity of mentally calculating any fractional part of a degree when it is other than four minutes (04') or a multiple thereof. The following is an example: assuming that an angle of ten degrees and thirty-three minutes (10 33') to the right is desired. See the table 32 which shows 33 (48-15). Then, move the ring 10 to the right ten degrees (10), and then move ring 10 in the same direction until the degree graduation on the ring 10 near the forty-eight minute (48') graduation on base 12 is registered thereon. By marking the point of angle at the fifteen minute (15') graduation directly to the left of 26 on ring 10, it will be the angle desired because, as indicated in the table 32, in order to determine said fractional part of a degree it is necessary to first add forty-eight minutes (48'), and then subtract fifteen minutes (15') therefrom, as the table 32 shows.

The graduations indicated by the numeral 23 on the base 12 of Figure l and on the base 39 of Figure 6 are adapted to be engraved on the upper surface of the base and can preferably be in red, whereas the degree graduations and the fifteen minute (15') graduations on the ring 10 of Figure 1 and on the ring 33 of Figure 6 are to be in black so that the graduations on the ring will readily be distinguishable from the graduations on the base. The dividing lines between the quadrants indicated by the numerals 24, 25, 26 and 27 are indicated by the numeral 13 on the base 12 of Figure l, and these dividing lines are indicated on the base 39 of Figure 6 by the lines 43. The dividing lines 13 or 43 are adapted to be engraved on the lower surface of the base, but on the upper surface thereof at the points directly under the degree graduations on the ring 10 of Figure l, or the ring 33 of Figure 6. Furthermore, the degree graduations and the fifteen minute (15') graduations on the ring 10 of Figure 1 and on the ring 33 of Figure 6 are engraved on the lower surface thereof. The purpose of this is to be able to secure exact registrations and readings when using the protractor.

For a further clarification to show how various angles are determined: Moving the ring 10, for example counterclockwise, to a point making an angle of thirty-two degrees and twenty-four minutes (32 24') at the point indicated by the numeral 26 on the ring 10, the other angles would be: one hundred twenty-two degrees and twentyfour minutes (122 24') at the point indicated by the numeral 25 on the ring 10; two hundred twelve degrees and twenty-four minutes (212 24') at the point indicated by the numeral 24 on the ring 10; and, three hundred two degrees and twenty-four minutes (302 24') at the point indicated by the numeral 27 on the ring 10.

I claim:

1. In a protractor, a circular base divided into quadrants, two of said adjacent quadrants each having seventysix degree (76) graduations spaced five degrees and four minutes (05 04') apart, a ring provided with a circular recess in its lower surface rotatably receiving said base, said ring being divided into quadrants, two of the adjacent quadrants of said ring being graduated in degrees, the outer periphery of said ring being tapered to a sharp edge and having graduations arranged at the dividing lines between the quadrants on the ring, said last named graduations being spaced fifteen minutes 15') apart, a disc arranged within said ring and connected to said base, the contiguous edges of said disc and ring being inclined and engaging each other.

2. In a protractor, a circular base divided into quadrants, two of said adjacent quadrants each having seventysix degree (76) graduations spaced live degrees and four minutes (05 04') apart, a ring provided with a circular recess in its lower surface rotatably receiving said base, said ring being divided into quadrants, two of the adjacent quadrants of said ring being graduated in degrees, the outer periphery of said ring being tapered to a sharp edge and having graduations arranged at the dividing lines between the quadrants on the ring, said last named graduations being spaced fifteen minutes (15') apart, a disc arranged within said ring and connected to said base, the contiguous edges of said disc and ring being inclined and engaging each other, there being registering openings in said disc and base for the projection therethrough of the users fingers,

3. In a protractor, a circular base divided into quadrants, two of said adjacent quadrants each having seventysix degree (76) graduaions spaced five degrees and four minutes (05 04') apart, a ring provided with a circular recess in its lower surface rotatably receiving said base, said ring being divided into quadrants, two of the adjacent quadrants of said ring being graduated in degrees, the outer periphery of said ring being tapered to a sharp edge and having graduations arranged at the dividing lines between the quadrants on the ring, said last named graduations being spaced fifteen minutes (15') apart, a disc arranged within said ring and connected to said base, the contiguous edges of said disc and ring being inclined and engaging each other, there being registering openings in said disc and base for the projection therethrough of the users fingers, said base, ring and disc being made of transparent material.

4. A protractor comprising a ring provided with a circular recess in its lower surface, a base seated in said recess, the inner portion of said ring being cutout to define a crossbar, means rotatably connecting said base to said crossbar, said base being divided into quadrants, two of said adjacent quadrants on the base each having seventy-six degree (76) graduations spaced five degrees and four minutes (05 04') apart, said ring being divided into quadrants, two of the adjacent quadrants of the ring being graduated in degrees, the outer periphery of said ring being tapered to a sharp edge and having graduations arranged at the dividing lines between the quadrants on the ring, said last named graduations being spaced fifteen minutes (15') apart.

5. A protractor as defined in claim 4, wherein said means comprises a securing element extending through said base and crossbar,

6. A protractor as defined in claim 4, wherein said means comprises a thumb screw extending through said base and crossbar, and a nut arranged in engagement with said thumb screw.

7. A protractor comprising a ring provided with a circular recess in its lower surface, a base seated in said recess, means rotatably connecting said base to said ring, said base being divided into quadrants, two of said adjacent quadrants each having seventy-six degree (76) graduations thereon spaced five degrees and four minutes (05 04') apart, said ring being divided into quadrants, two of the adjacent quadrants of said ring being graduated in degrees, the outer periphery of said ring being tapered to a sharp edge and having graduations arranged at the dividing lines between the quadrants on the ring, said last named graduations being spaced fifteen minutes (15') apart.

8. In a protractor, a circular base divided into quadrants, two of said adjacent quadrants each having seventysix degree (76) graduations spaced five degrees and four minutes (05 04') apart, a ring provided with a circular recess in its lower surface rotatably receiving said base, said ring being divided into quadrants, two of the adjacent quadrants of said ring being graduated in degrees, the outer periphery of said ring being tapered to a sharp edge and having graduations arranged at the dividing lines between the quadrants on the ring, said last named graduations being spaced fifteen minutes (15') apart, a disc arranged within said ring and connected to said base, the contiguous edges of said disc and ring being inclined and engaging each other, and a table on said protractor for eliminating the necessity of mentally calculating any fractional part of a degree when it is other than four minutes (04') or a multiple thereof.

No references cited.

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