US200048A

US200048A - Improvement in compasses

Info

Publication number: US200048A
Authority: US
Publication date: 1878-02-05
Anticipated expiration: 1895-02-05

Description

A. P. FRESHMAN. Compass.

No. 200,048. Patented Feb. 5,1878.

ATTEST: INVENTOR: Maw Qfi'whmm N. PETERS. PBOTO-UTHOGRAPHER, \IASHINGTQN, 0 C4 UNITED STATES PATENT OFFICE.

ANDREW P. FRESHMAN, OF BELLEVILLE, ILLINOIS, ASSIGNOR OF ON E-HALF HIS RIGHT TO GEORGE EISENBERG, OF SAME PLACE.

IMPROVEMENT Specification forming part of Letters Patent No. 200,048, dated February 5, 1878 application filed November 26, 1877.

To all whom it may concern Be it known that I, ANDREW P. Faust:- MAN, of Belleville, Illinois, have made a new and useful Improvement in Compasses, of which the following is a full, clear, and exact description, reference being had to the annexed drawings, making part of this specification, in which- Figure 1 is a side elevation of a compass containing the improvement, the legs being opened apart; Fig. 2, an elevation, showing the compass closed; Fig. 3, a detail, showing the compass having caliper-points; and Fig. 4, a cross section taken on the line 00 w of Fig. 2.

Similar letters refer to similar parts.

By means of the present invention theparallelism of the points of the compass-legs is preserved whatever the angle the legs are opened out to.

The improvement also relates to the provision by which the points of the legs can be readily replaced or changed.

Referring to the drawings, A represents a compass having my improvement. The legs a a arepivoted to each other at b in the usual manner; but they are each-(and similarly) made in two sections, a and c and a and 0, jointed, respectively, at cl and d. The legs, at their upper ends, are similarly extended a short distance beyond the pivot b. A lever or rod, 6, is pivoted at one end, 6 to the extension of the leg at, and at the other end, 6 to an extension, 0 of the section a. A similar rod, f, is similarly pivoted at f to the leg at, and at f to an extension, 0 of the section 0. The extensions 0 and o are, respectively, on the outer sides of the legs a and a.

The various parts being thus arranged, extended, and connected, as the legs a a are opened apart or closed together the rod 6 causes the sections a and a to turn upon each other, and the rod f causes the sections 0 and a to turn upon each other, and the effect of the combined movements is to cause the sections 0 and c to remain parallel with each other in all positions of the sections a and a,

. for all the parts of the compass are so arranged relatively to' each other, and so proportioned, that the sections 0 and c are parallel when the compass is closed, and that, as the compass is opened, the movements of the sections 0 and a, respectively, upon the sec tions at and a are just sufficient to keep the sections 0 and 0 parallel. The relations, respectively, of the pivots e and f to the pivot b affect, of course, the relations of the pivots f and e to the pivots d and 01". As the one is changed the other must be correspondingly modified.

The lower ends of the sections 0 and 0 may, if desired, be sharpened to constitute the points of the compass legs. I preferably, however, make the extreme ends 9 g of the sections detachable. This enables a point to be renewed with but slight expense. It also enables differently-shaped points to be used. In Fig. 3, points h h, shaped suitably for calipers, are shown.

That portion of the improvement first above described is especially useful in connection with such points, for, in making nice measurements with calipers, it is desirable for the' extreme points to be applied as nearly as is practicable in the line of the diameter being measured. The keepingof the sections 0 and 0 parallel enables the points to be thus presented. v

This improvement is valuable not only in compasses, but also in drafting-instruments, and other tools that consist mainly of two parts or legs pivoted together at one end, and that are used in-measuring.-

I am aware that dividers having what is termed a parallelogram connected with a stanchion depending from the head of the dividers have heretofore been constructed.

I claim.

The hereindescribed compass, consisting