US 1402269 A
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Description (OCR text may contain errors)
J. L. TANNER.
APPLICATION FILED SEPT.28, 1920.
1,402,269. t t d Jan. 3, 1922,
ml \1 lLUIE umrao STATES ears J' OHN L. TANNEB, OF DALLAS, TEXAS.
Specification of Letters Patent.
Patented Jan. 3, 11922.
To all whom it ma concern:
Be it known that I,\JOHN L. TANNER, a citizen of the United States, residin at Dallas, in the county of Dallas and tate of Texas, have invented certain new and useful Improvements in Drafting Imple- 1 ments, of which the following is a specification.
This invention relates to new and useful improvements in drafting implements.
The invention has particularly to do with an implement for laying out ,or plotting curves of different degrees and combining line 3-3 of 1n a single implement the functions of a plurality of implements.
In carrying outthe invention I provide a flat plate or member in which a plurality of curved slots is provided. Each slot has two curved longitudinal edges, one of which gives an even degree curve and the other of which produces a curve of a certain scale'at a given measurement. For instance the bot- .tom curves of the slot may successively range from one degree; while the to i curves may range from 0 30' to 12 30. his arrangement gives a 30 curve at the top of each slot. This implement is particularl useful in plotting railroad alinement. l t is also proposed to make a portion at one end of each slot tangent thereto and this is particularly useful in engineering work.
The implement may be provided also with scales and graduati'ons along its margins, but these are not essential elements of the invention.
The invention will be more readily understood from a reading of the following specificationv and by reference to the accompanying drawings, in which an example of the invention is shown, and wherein:
Fig. 1 is a plan view of an implement constructed in accordance with my inven tion,
Fig. 2 is an edge view of the same, and Fig. 3 is a cross sectional detail on the Fig. 1. In the drawings the numeral 10 designates a flat plate or member which may be made of any suitable material, such as celluloid composition. It is preferable to use a substantially transparent material, but this Y I plate having a plurality of slots extending is not essential.
substantially longitudinal slots 11, each beginning at the left hand margin of the plate and curving downwardly at the right hand.
end. In Fig. 1 the lower edge 12 of the plate Is the bottom andthe upper edge 13 is the top3i The slots curve toward the bottom.
ach slot has two longitudinal edges or sldes 14 and 15, the bottom edges being designated by 14 and the top edges by 15. At the left hand end of each slot a portion 11, tangentlal to the curve of the slot is provlded.
Designations are provided .at the left hand end of each slot indicating the degree of the curve represented by the lower edge 14 thereof. In Fig. 1, I have shown thirteen slots and-the curves represented ran e from one degree to thirteen degrees, but thls tion 11' registers with the line of the drawing to which the curve-is to be added. Should the desired curve be eight degrees, the plate is placed so that the portion 11' of the slot having 8 degrees at its end will match along its lower edge with the line of the drawing. The lower edge 14 of the slot will give the desired curve and the draftsman has only to trace along the lower edge of the slot, which acts as a guide. The same procedure is employed for tracing any other curve.
A scale 16 may be placed along the margin at the bottom of the plate and the marginal portions 17 of the other three edges may be used for the graduations of a protractor, or any other measurement or scale. It is preferable to round the corners of the plate so that the plate when made in a small size may be more readily slipped into a coat pocket when used in the field and will not catch on objects on the drafting table.
What I claim, is:
In a drafting implement, an elongated longitudinally thereof, said slots being lontions indicating the degree of curvature of gitudinally curved, each slot having a pair the lower edges of said slots, said plate also of longitudinally curved edges, the edges of having designations indicating the degree each slot having different degrees of curvaof curvature of the upper edges of said slots. 10 ture. said plate being provided at the cor- In testimony whereof I affix my signature. responding ends of said slots with designa- JOHN L. TANNER.