US373100A - Protractor and circle-scribing attach ment for rulers - Google Patents

Description

(N0 Modl.) I

J1 G. SMITH. PROTRAGTORY AND CIRCLE SG'RIBING' ATTAGHMENT FOR RULERS. No. 373,100. Patented Nov. 15, 1887.

Inaenfir N. FILTERS. PhMo-Lilhngnphnr. Waxhingto'm D. C.

UNITED STATES PATENT GFFICE.

JAMES G. SMITH, OF J AMESTOWN, NEW YORK.

' PROTRACTORAND CIRCLE-SCRIBING ATTACHMENT FOR RULERS.

SPECIFICATION forming part of Letters Patent No. 373,100, dated November 15, 1887.

Application filed March 30, 1887. Serial No. 232,984. (No model.)

T on whom it may concern:

Be it known that 1, JAMES G. SMITH, a citizen of the United States, residing at Jameswood, and the parts are not liable to become out of order.

In the accompanying drawings, Figure 1 is a top view of a ruler and its attachments constructed in accordance with my invention. Fig. 2 is a transverse vertical section of the same. Fig. 3 is a top View of the sheet-inetal clamp opened out. Fig.4 is a side View of the protractor index, and yielding pad, with rivet uniting them. Fig. 5 is a view from the under side of the ruler and its attachments,

4 showing the rubber or other yielding pad of the device.

In said drawings, A represents a ruler, preferably made of wood, and having the ordinary subdivisions and a beveled edge, a, so that it can be used for ruling lines with a common pen without danger of blurring. To facilitate its use to draw angles, circles, 850., a short sheetmetal strap, B, is bent half-way of its length and folded so as to clasp said roller, and the branches of said clasp are retained substantially by means of a rivet, c, passing through them close to the edge of the ruler; and upon the lower end of said rivet is placed a washer or pad, d, of a soft and yieldingsubstance, substantially as india-rubber, to sufficiently ad here to paper or other substance upon which the ruler may be applied, and, if pressed upon, permit the ruler to be revolved and a circle be described without danger of shifting its center.

To retain a pencil connected with the ruler, a ring or screweye, e, is attached to one end of the ruler, and when it is to be used to describe a circle the point of a pencil is inserted in said eye and used to revolve the ruler. To indicate the size of the circle to be described, the edge of the strap B is cut away to form a pointer, b, at the same distance from an axisline passing through the rivet c as the outer end of the eye 6 stands from the end of the ruler. To prevent the ruler from accidentally slipping through its clasp, the latter has a clamping-screw,f, the inner end of which bears against the face of the ruler.

To permit any given angles to be described with the ruler, there is placed upon the clasp B a protractor, g, having its face subdivided into degrees and its center mounted upon the outer end of the rivet 0, so that by retaining the clasp immovable with one hand its opposite end can be revolved and a true circle described.

As the ruler is of uni form thickness throughout its length, the clasp can be made to occupy any desired point upon it, and it can be entirely removed therefrom and the scale-ruler A be used simply as a ruler.

Having now fully described my invention, I claim I In combination with a scale-divided ruler having a beveled edge, the attachment consisting of a sheet-metal clasp, B, having a pointer, 12, a yielding pad on the under side thereof and a protractor on its upper side, and a ring or screw-eye in the end of said ruler, substantially as and for the purpose described.

In testimony whereof I afiix my signature in presence of two witnesses.

JAMES G. SMITH.

Witnesses:

FRANK W. SrEvENs, FRED. R. PETERSON.

Images