US575105A

US575105A - Plan i meter

Info

Publication number: US575105A
Authority: US
Publication date: 1897-01-12
Anticipated expiration: 1914-01-12

Description

(No Model.)

-B. E.OHOLLA R PLANIMETER.

Patented Jan. 12, 1897.

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I reference being had to the accompanying which-- ter; 2, the perpendicular portion, terminattively, the positions shown at 10, 11, and 12.

v UNITED STATES ATEN'I FFICE.

BYRON E. CHOLLAR, OF ST. LOUIS, MISSOURI.

PLANIMETER.

SPECIFICATION forming part of Letters Patent No. 575,105, dated January 12, 1897. I Application filed July 16, 1896. Serial No. 599,371; (No model.)

To all whont it may concern:

Be it known that I, BYRON E. CHOLLAR, a citizen of the United States, residing at the city of St. Louis, in the State of Missouri, have invented a certain new and useful Improvement in Planimeters, of which the following is a full, clear, and exact description,

drawings, forming part of this specification. My invention relates to an improvement in instruments for ascertaining the area of irregular plane surfaces. I am aware that the instrument itself is old, but my invention relates to an improved attachment therefor.

The device is shown in the drawings, in

Figure I illustrates a perspective view thereof. Fig. II illustrates a diagram showing the various positions of the parts during the measurement of a surface.

1 is the horizontal portionof the planimeing in a point, said point being adapted to trace the boundaries of the surface to be measured.

3 is the second perpendicular portion of the instrument, being in the same plane as the other portions and terminating in a flat knifeedge, the said edge being in the plane of the portions 1, 2, and 3.

4 is a sleeve adapted to fit over and support the upright 2.

5 is a ring attached to the sleeve 4 by means of the braces 6.

7 is a knife-edge in line with point 2 and provided with a cut at its point of contact and situated on the end of upright 3.

For the purpose of illustrating the use of my invention we will assume that the circle 8 incloses the area to be ascertained. By placing the pointed end of 2 in the center of this circle the edge. 7 will fall upon the place 7 as shown in Fig. II. The point of 2 is then moved down the radius r to the circumference. The supporting-ring 5 will then be in the position shown at 9, while the center of edge 7, which has been allowed to swing freely, will be at 9. The point 2 being traced over the circumference, as shown by the arrow, causes the ring 5 to take, consecu- The edge 7 beingin the meantime allowed to I travel freely will be in the positions 1O 11 12. When the point has returned to the end of the radius r, the edge 7 will be at 13. Then the point 2 is traced back up the radius r to the center, at which place it will be found that the edge 7 rests at 14. The distance from 14 to 7, the place of starting, multiplied by the distance from point 2 to the point of contact of edge 7 will give the area thereof. Formerly the bent wire 1 2 3 was all that was used. As great care and exactness are required, the necessary freedom of the loose end 7 was impaired by the handling of the device. The pointed end 2 must exactly trace the boundary of the surface, while the end 7 must be allowed to move freely. Holding the instrument in the hand prevented this. I have therefore provided the collar 4, through which the pointed end 2 plays, supported by braces from a fiat ring 5. The ring 5 is large enough to expose the pointed end 2 to ones view. The collar 4 holds the instrument upright, and the braces 6 afford a convenient means for holding or moving the device. By its use accurate results may be obtained with an case that has not before been possible.

What I claim, and desire to secure by Letters Patent, is-

l. The combination with a planimeter, of a frame adapted to seat on the surface to be traced whereby the pointed upright of the planimeter is supported in contact with the said surface; substantially as described.

2. The combination of a pointed upright, a knife-edge upright, and a connection between the two, a collar adapted to support said pointed upright, and a horizontal ring secured to said collar by means of braces, substantially as described.

3. The combination of tracing-upright 2, knife-edge upright 3, and connection 1, all made integral, with supporting-collar 4 adapted to receivesaid tracing-upright 2, horizontal ring 5, and braces 6, likewise made integral, substantially as described.

BYRON E. CHOLLAR.