US665316A - Protractor. - Google Patents

Description

Patented 1an. I, I90I.

C. P. FAY.

PRUTRAGTUR.

4 (Applicgation led Jan. 30, 1899.\

(No Model.)

7? wmk A f /f,/W/+H Tn: noRms paens cn, uovo-nwo., WASHINGTON. n. c.

CHARLES P. FAY, OF CHICOPEE, MASSACHUSETTS, ASSIGNOR TO THE J. STEVENS ARMS AND TOOL COMPANY, OF SAME PLACE.

PROTRACTO R.

SPECIFICATION forming part of Letters Patent N o. 665,316, dated January 1, 1901.

Application tiled January SQ, 1899. Serial No. 708,799. (No model.)

To all w/tom, t 1er/ty concern.'

Be it known that I, CHARLES P. FAY, a citizen of the United States of America,and a resident of Chicopee, in the county of Hampden and State of Massachusetts, have invented certain nevt7 and useful Improvements in Protractors, of which the following is a full, clear, and exact description.

This invention relates to improvements in protractors of the class having combined with the graduated semicircular plate the centrally-pivoted radins-bar or protractor-arrn, which is adapted to be swung at any angle from the base edge of the protractor-plate, which description of protractor is extensively used by mechanics in setting bevel-squares or universal squares at any required angle, by draftsmen in setting T-squares with the blades thereof at any angle to the head, and by architects, surveyors, and others.

The invention more particularly relates to interlocking devices whereby the radins-bar or protractor-arm after having been set at any angle required may be locked in its set position and held safely against accidental displacement, but susceptible of being readily disengaged and afterward lo'cked for a new setting of the bar, the object being to provide a protractor of the kind referred to which is extremely simple and cheap of construction, very convenient in operation, and accurate in its measuring or angle-indicating capability.

The invention in its broader aspect is defined as comprehending a new and improved protractor, consisting of a protractor-plate and a protractor-arm or radius-bar pivoted thereon, the plate having a series of teeth or serrations corresponding to the degree-graduations thereon and the arm having a nnernber to register with the protractor-graduations and provided with a device adapted for convenient detachable engagements with the teeth of the plate; andthe invention also consists in the specic constructions and combinations of parts, all substantially as shown, described, and set forth in the claims.

Reference is to be had to the accompany-- ing drawings, in which the present improved adjustable protractor is fully and clearly illustrated, and in which- Figure l is a plan view thereof". Fig. 2 is a sectional View on line 2 2, Fig. l. Fig. 3 is an edge view of the protractor, showing the protractorarm as swung into its position, whereby it is disengaged from the protractorplate to permit the'adjustinent of said arm at any angle from the base of said plate. Fig. t is a plan View of portions of the protractorplate and of the protractor-arm, especially illustrative of the provisions whereby the one is detachably intel-locked with the other. Fig. 5 is a sectional View similar to Fig. 2,

but showing a slight modification.

Similarcharacters of reference indicate corresponding parts in all of the views.

In the drawings, A represents the protractor-plate, of substantially selnicircular form, having the straight base edge a, as usual, and having its face around adjacent its arc-formed edge provided with the degree -indicating marks or graduations b, and the said arcformed edge of the protractor is provided with a series of notches or teeth b, corresponding to and one for each of the graduations.

B represents the radius-bar or protractorarm lying under and next to the protractorplate, being pivotally connected thereto by the headed screwfand clam p-nut g, the extremity of said arm projecting beyond the toothed edge of the protractor-plate, said extremity having formed thereon or permanently affixed thereto a member or shoe h, which is provided at its inner edge with several teeth t, which are adapted to engage in the teeth edgewise provided on the protractorplate. The height of the shoe, as shown, is approximately the same as the thickness of the plate, and the same is provided with the upstanding studj, having at its upper end the overhanging head m. The height of the stud is slightly greater than the thickness of the plate, and the head m is inwardly beveled, as indicated at n, and is centrally provided with an indicating mark or line o, extending centrally and longitudinally relative to the protractor-arm.

In order to adj ust the protractor-arrn, which is of thin spring metal, the stud is pressed downwardly to bring t-he bevel-head to overlap and lie closely on the upper face of the protractor-plate, thereby causing the shoe h IOO to be moved clear below the lower face of the protractor, the teeth of the shoe being disengaged from the teeth of the protractor-plate, alias clearly indicated in Fig. 3. The protractor-arm is now swung until the indicating-line o on the head of the stud comes to the graduation indicating the number of degrees at which the protractor is to be set, whereupon the downward pressure is released, permitting the teeth of the shoe h to match into and interlock with the teeth of the plate, firmly assuring the retention of the bar in its given set position, so that there will be no liability when the instrument is placed against an adjustable square or other tool or work of the arm becoming displaced from its set position.

Vhile the description hereinabove given is specific in detailed statement of the precise forms or construct-ions and arrangements of the parts of the protractor as shown in the drawings, I may, under the foregoing statement of invention and the terms of certain of my claims, carry out my invention by the employment of substantially the same idea of means, but somewhat different in matters of detail-as, for instance, I may provide the protractor-arm B with the member or device for engaging the serrations or teeth of the protractor-plate, which member is movable on or relative to the arm proper for the engagement and disengagement with the teeth of the plate, and in Fig. 5 the radius-bar or protractor-arm B is constructed in the two sections o and 02, the one of which is engaged with the other for an endwise sliding movement, as permitted by the pin-and-slot engagemen t, (indicated at t.) Therefore under this construct-ion a distention of the radiusbar, instead of a bending thereof across its normal plane of occupancy, enables the disengagement of the teeth i' of the part hat the outer extremity of the bar from the teeth or seri-ations at the edge of the protractor-plate.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is-

l. A protractor-plate having a series of degree-graduations, and provided with a series of corresponding teeth, combined with a protractorarm pivotally connected to swing around on the plate, carrying an indicating part to register with the said graduations', and having a part movable relatively to the teeth of the plate, to engage and disengage the same.

2. A protractor-plate having graduations, and edgewise provided with corresponding teeth, combined with the pivotally-connected protractor-arm constructed with a portion or member projected beyond the edge of the plate, and provided with an upstanding part which at its edge toward the plate is toothed, the said arm which carries the upstanding part being composed of spring metal and capable of being swung transversely of the plane of the plate for disengagement and rengagement with the latter, substantially as described.

3. A protractor-plate having graduations and edgewise provided with teeth corresponding thereto combined with a protractor-arm of spring metal pivotally connected to the plate and having at its extremity which is projected beyond the edge of the plate, the upstanding shoe h which at its edge toward the plate is toothed, and said extremities furthermore having the upstanding stud with the head which overhangs the edge of the protractor-plate, and which has an indicator to register with the graduations of the plate, substantially as described.

1. The combination with 'the protractorplate having the degree-graduations and corresponding edgewise serrations or teeth, of the protractor-arm B pivotally connected to the base portion of the plate and having its free extremity extended beyond the curved edge ot' the plate and provided with the shoe 7L having at its edge toward the plate the teeth 'i and having the upstanding stud j of a height slightly greater than the thickness of the plate and provided with the head m which overhangs the edge of the plate, and which has the beveled part n provided with the indicatingmark o,all substan tially as described and shown.

Signed by meat Springfield, Massachusetts, this 4th day of November, 1898.

CHARLES P. FAY.

Witnesses:

WM. S. BELLOWS, M. A. CAMPBELL.

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