US1028742A - Combination bevel-protractor. - Google Patents

Description

J. LA FOLLETTE.

COMBINATION BEVBL PROTRAGTOR.

APPLICATION FILED JULY 28, 1911. 1,028,742.

Patented June 4; 1912.

WITNESSES:

A TTOR/VE Y COLUMBIA PLANOORAPH 60.. WASHINGTON, l7v c srs COMBINATION IBEVEL-PROTRACTOR.

Specification of Letters Patent.

Patented June 4, 1912.

Application filed July 28,1911. Serial No. 641,154.

To all whom it may concern:

Be it known that I, J osErH LA FOLLETTE, a citizen of the United States, residing at Portland, in the county of Multnomah and State of Oregon, have invented certain new and useful Improvements in Combination Bevel-Protractors, of which the following is a specification.

My invention relates to means for laying out angles and computing lengths of material in building construction work, and is an improvement on an instrument of this character, for which Letters Patent of the United ,States were granted to me June 27th, 1911,.

The object of my invention is to provide an instrument of this character, which can be used to advantage both by the mechanic.

in which,

Figure 1 shows a protractor embodying my invention and provided with a straightedge attachment, Fig. 2 is a front elevation of said straight-edge attachment, Fig. 3 illustrates my device fitted with a protractor stock, parts of said stock removed in order to clearly show its construction, and Fig. 4 is a perspective elevation of the protractor stock shown in Fig. 3.

Referring in the first instance to Fig. 1 plate or quadrant a is provided with a series of scales 0, (Z, 6, giving the angles of side-cuts for roof-hips and valleys, and a protractor scale Z), whereas the opposite face of the quadrant, as illustrated in Fig. 3, is made with a series of scales 7, g, h, giving lengths of rafters and angles of their top and bottom cuts. This arrangement of scales I have found most convenient in practice, but I wish it understood that I may substitute any other combination or arrangement of scales. Said scales are all concentric, and plate a is at scale center 2' made with a notch 7' adapted to receive it:

pivot is of protractor stock Z. The latter comprises two parts m, m, identical in form and held together in their proper relation by studs 72 and 0%. On stud 71., between parts m, m, is rotatably hung an eccentric cam 0 provided with a fingerpiece p, and in close proximity to said cam is mounted a shoe g, held in place by one or more studs r. Perforations s of said shoe are elongated to permit said shoe to move longitudinally in stock Z. When desired to mount stock Z on plate a, pivot 70 is first caused to enter notch j, whereupon the stock is rotated on said pivot, until shoe Q engages and rides on the peripherical surface t of the plate, as shown in Fig. 3, and it is readily seen that the stock, as long as the shoe is in engagement with edge It, is securely hung on the plate. The stock is set by turning it until its reading edge u coincides with the desired reading on one of the scales, whereupon it is locked against peripherical displacement on the plate by rotating eccentric cam 0, which in its turn clamps shoe 9 against surface 25.

Stock Z is preferably made of thick material, so as to insure a good surface contact between said stock and the edge of the timber to be marked for cutting, but in order to provide a more convenient instrument for draftsmens use, I substitute the combination shown in Fig. 1, in which a stock v is mounted on blade a. The construction of this stock, so far as the attaching and locking arrangements are concerned, is identical with the construction of stock Z, but it differs from the latter in other respects. It is made in two parts to, to, one of which, as w, extends beyond pivot y and forms a blade or straight-edge w.

Stock 4) is made of very thin metal, in order to be conveniently used on paper drawings, where my device may be used in connection with a T-square by bringing either edge 2, 2 of the stock in contact with the edge of the T-square, or it may be used independently on oblique lines by alining an edge 2, z with said oblique line. Fi-

' nally my device itself may be used as a T- square by placing edge 2 or 3 of plate a against the edge of the drawing board. In cases where fine protractor measurements are required, I may add a Vernier scale as indicated by reference number 4 in Fig. 1.

Having thus described my invention, I claim:

1. In a device of the character described in combination with a quadrantal scale bearing plate provided atthe apex with a notch the bottom of which coincides with the scale center, a pair of interchangeable stocks each adapted to fulcrum in thenotch of said plate, and means for clamping the stocks on the plate, all as and forthe purpose set forth.

2. In a device ofthe character described in combination with a quadrantal scale bearing plate provided at the apex with a notch the bottom of which coincides with the scale center, a pair ofinterchangeable stocks, each stock comprising two members and provided with means for clamping the two members together, said means comprising two studs one at each end of the stock, the inner stud adapted to fulcrum in said notch, and means for clamping the stock on the plate, said means cooperating with the Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. G.

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