US2421395A - Bevel protractor - Google Patents

Description

JuneB, 1947. w. H. SCHNEIDER 2,421,395

BEVEL PROTRACTOR Filed Aug. 24, 1944 INV ENT OR.

Patented June 3, 1947 UNITED STATES PATENT OFFICE BEVEL PROTRACTOR William H. Schneider, Milwaukee, Wis.

Application August 24, 1944, Serial No. 550,925

9 Claims.

The invention relates to bevel protractors.

The general object of the invention is to provide a protractor which may be made up of several stampings that may be readily and economically produced and which stampings may be readily modified to fit the selling price of the tool for different types of sales outlets.

The invention further consists in the several features hereinafter described and more particularly defined by claims at the conclusion hereof.

In the drawings:

Fig. 1 is a side elevation View of a bevel protractor embodying the invention, parts being broken away and parts being shown in section;

Fig. 2 is an end elevation view of the protractor looking in the direction of the arrow A;

Fig. 3 is a horizontal sectional view taken on the line B-B of Fig. 1 and looking in the direction of the arrows;

Fig. 4 is an elevational View of a modification of one of the parts;

Fig. 5 is an end view of the part shown in Fig. 4;

Fig. 6 is a front view of the clamping ring structure;

Fig. 7 is a side view of the structure shown in Fig. 6;

Fi 8 is an elevational view showing a modified form of frame structure;

Fig. 9 is an end view of the frame shown in Fig. 8.

The bevel protractor embodying the invention includes a frame or support, a dial rotatably mounted in said frame, a straight-edge carried by said dial, and means for clamping the dial in different radial positions of adjustment relative to said frame.

In Figs. 1 to 3 the frame is formed by a pair of complementary plate stampings ll] having angled base portions 1 l providing a. straight edge and upright portions l2 which are spaced apart to receive indicator plates I3 to which they are secured by rivets I 4 and which have other spaced portions IE to receive the dial structure between them and which at these portions [5 have circular apertures [6 formed therein in which the pivot-forming and dial-clamping cup-shaped members I! having flanges l8 engaging said frame are mounted.

In Figs. 1 and 3 the indicator plates l3 are shown as a pair of complementary plate stampings secured together b rivets l9 and having parts 20 adjacent alined openings 20 pressed out to house a spirit level bulb 2| which is cemented in position during the assembly of the plates.

Instead of using the indicator plates 13 and the spirit level bulb, I may use in some instances a cheaper construction shown in Figs. 4 and 5 in the form of a single indicator plate 22 which is secured to the frame plates by the rivets I4. Where the indicator plates l3 or the plate 22 is used, the total thickness thereof is slightly greater than the thickness of the dial plate and straightedge hereafter referred to. For a still cheaper construction one of the frame plates I0 may have an indicator portion 23 formed integral therewith which slightly overlaps the edge of the dial plate 24 and the base plates l0 spaced apart by a spacing disk 25 through which a holding rivet 26 passes.

The dial structure includes the dial plate 24 which is cut off on a cord 21 to form a. guide surface for a straight-edge 28 whose sides are slidably mounted between a pair of reinforcing and straight-edge guide circular plates 29 that are secured to and against opposite sides of the dial plate 26 by rivets 30. Both plates 29 and the dial plate 24 have circular center openings 3| alined with the openings It in the frame plates Ill. The cup-shaped pivot members or disks ll of steel or other resilient metal project into these alined openings l6 and 3|, and their bottom portions are designed to be normally spaced apart and be drawn together by a centrally disposed rivet 32 extending through said members and putting them under a predetermined tension, so that these members exert a certain amount of clamping tension between the dial structure and the supporting frame plates [0.

The dial plate 24 has the scale markings 33 cut or otherwise suitably formed therein, and in Fig 1 I have shown a mark for every five degrees of dial periphery. These markings cooperate with the base mark 34 on the indicator which may also have the single degree markings 35 on either side of this base mark, so that the dial may be set by scale to any single degree between the five degree divisions, the markings 35 thus acting as a Vernier scale.

For clamping the dial structure in any desired set angular position, I provide a clamping screw 36 passin through openings 31 in the bottoms of the pivot members l1 and provided with a thumb nut 38 so as to clamp these members between the head of the screw and said nut and thus increase the clamping tension over that of the initial tension exerted by the rivet 32.

For clamping the straight-edge 28 in adjusted lengthwise position relative to the dial structure and the frame, the guide plates 29 have radially disposed alined key slots 39 formed therein in which a clamping key 48 is slidably mounted, the dial plate 24 at this portion being slotted to accommodate said key. This key 40 has a longitudinal slot 4| formed therein to receive the straight-edge 28 and a projection 42 engaging in a lengthwise extending recess 43 formed in one side of said straight-edge. The key has a screw threaded end 44 which extends into an opening 45 formed between cut out portions of the clamping disks or pivot members H, and at this point semi-circular portions 46 of sides of said disks are pressed inwardly to stiffen the metal and to form tapered semi-circular centering flanges that are engaged by the inwardly tapered end 48 of the straight edge clamping thumb nut 49 mounted on the threaded end 44 of the key 48, so that tightening up of said nut causes the key 40 interlocked with the straight-edge 28 through the projection 42 and the recess 43 to draw the inner edge 28 of the straight-edge against the chord surface 21 of the dial plate 24, the nut in being tightened tending to draw in the flanges 46 and I8 and thus center and tension the clamping connection in the pivot If. The thickness of the dial plate 24 is slightly greater than the blade 28, so that when the three plates of the dial structure are secured together, the blade will have a free sliding movement between the guide plates 29.

In some instances it is desirable to use the protractor as a fixed square or ninety degree protractor, and for this purpose-I have provided, as shown in Figs. 1 and 3, means for positively locking the dial plate to the frame to hold the straight edge 28 at right angles to the base of the frame l0. This locking means includes a locking pin 50 which is slidably mounted in a bore formed by alined openings in the plate 24 and plates 29 and engaged by a spring 52 to move its outer end into an opening 53 in one of the frame plates in when the straight-edge 28 is in a right angled or squared position. To facilitate release of the pin 59, a spring finger 54 is mounted on the frame having one end'55 mounted in a slot 56 in the part l5 of one of the frame plates I0 and anchored in position by a rivet 51 secured to said frame plate. -Pressing on the free end of thefinger 54 will'm'ove the pin 50 inwardly out of the opening 53, so that the dial structure may be used to set the straightedge to other angles than a right angle. This spring 54 also prevents the pin'fill from falling out of the dial structure.

It will be noted that the frame plate It! shown in Fig. 8 has the extension it), and this type of frame is especially designed'for use of the protractor by woodworkers.

I desire it to be understood that this invention is not to be limited'to any specific form or arrangement of parts except in so far as such limitations are included in the claims.

What I claim as my invention is:

1. In a bevel protractor for machinists, carpenters, and the like, the combination of a fixed frame having a base providing a straight edge and spaced portions provided with alined apertures, a straight edge carrying dial having a centrally located. aperture alined with the apertures of said base portions, a pair of flanged cup-shaped resilient metal pivot disks extending into the alined apertures of said base and dial from opposite sides with their flanges engaging said base and .having their bottom portions normally spaced from each other, and means for clamping'said disk together and exerting a tensioning 4 pressure through said flanges between said base and said dial.

2. In a bevel protractor for machinists, carpenters, and the like, the combination of a fixed frame having a base providing a straight edge and spaced portions provided with alined apertures, a straight edge carrying dial having a centrally located aperture alined with the apertures of said base portions, a pair of flanged cup-shaped resilient metal pivot disks extending into the alined apertures of said base and dial from opposite sides with their flanges engaging said base and having their bottom portions normally spaced from each other, means for clamping said disk together and exerting a tensioning pressure through said flanges between said base and said'dial, and a clamping nut for drawing the bottoms of said disks together to further increase their clamping pressure.

3. In a bevel protractor for machinists, carpenters, and the like, the combination of a fixed frame having a base providing a straight edge and spaced portions, a straight edge carrying dial, means for pivotally mounting said dial between the spaced portions of said base, a spring pressed locking pin mounted. in the dial and engageable with the opening in the base to lock the dial in a ninety degree position, and a spring finger mounted on said base engageable with said locking pin and adapted to be pressed inwardly by the operator to release the same from locking engagement with said base.

4. In a bevel protractor for machinists, carpenters, and the like, the combination of a fixed frame having a base providing a straight edge and spaced portions providedwith alined apertures, a straight edge carrying dial having a central opening alined with the apertures in said base, pivot forming and resilient clamping means extending into said alined apertures of said base and dial, means for putting said clamping means under initial tension to resist turning of said dial relative to said base, and manually adjustable means for further increasing the tension of said clamping means.

5. In a bevel protractor for machinists, carpenters, and the like, the combination of a fixed frame having a base providing a straight edge and spaced portions provided with alined apertures, a dial including a dial plate and reinforcing plates on opposite sides thereof forming at one side a guide for a straight-edge, a straightedge slidably mounted between said last named plates, said dial plate and reinforcing and guide plates having alined apertures alined with the apertures of said base portions, pivot forming and clamping means extending into said alined apertures of said base and dial including means for creating an initial tension between said dial and base to resist turning movement of the dial relative thereto, and manually operable means for increasing the tension of said clamping means between the dial and said base, and adjustably tensioned means carried by the dial and engageable with the straight-edge for clamping the straight-edge to the dial in adjusted position.

6. In a bevel protractor for machinists, carpenters, and the like, the combination of a fixed frame having a base providing a straight edge and spaced portions with alined apertures, a dial having an apertured portion alined with the apertures of said base portions and a straight edge guide portion, a straight edge slidably mounted in said guide portion, a pair of flanged cupshaped resilient metal pivot disks extending into the alined apertures of said base and dial from opposite sides with their flanges engaging said base and having their bottom portions normally spaced from each other and having inwardly extending semi-circular tapered portions adjacent the guide for said straight-edge, means clamping said disk together and exerting a tensioning pressure through said flanges between said base and said dial, a straight-edge clamping member having interlocking connection with said straightedge and a threaded end extending into the apertured portion of said dial, and a clamping nut engageable with said threaded portion with a tapered end in engagement with said tapered portions of said disks to clamp the straight-edge to the dial.

7. In a bevel protractor for machinists, carpenters, and the like, the combination of a fixed frame including angles plates provided with alined apertures and an indicator member disposed between the plates and secured thereto and spacing the same apart, a straight edge carrying dial means extending through the apertures of said angled plates for pivotally mounting the dial between said plates, and means for clamping the dial in adjusted radial position relative to said base.

8. In a bevel protractor fOr machinists, carpenters, and the like, the combination of a, fixed frame including angled plates provided with alined apertures and an indicator member including a pair of plates secured together and to said angled plates and spacing said last named plates apart, a straight edge carrying dial, means extending through the apertures of said angled plates for pivotally mounting the dial between said plates, and means for clamping the dial in adjusted radial position relative to said base.

9. In a bevel protractor for machinists, carpenters, and the like, the combination of a fixed frame having a base providing a straight edge and spaced portions provided with alined apertures, a dial having a central opening alined with the apertures in said base, a straight-edge slidably mounted on the dial, a pair of pivot forming and dial clamping resilient members extending into said alined apertures of said base and dial, means mounted on said members for tensioning the same to resist turning of said dial relative to said base, and means for clamping said straightedge in adjusted position relative to the dial and engaging said resilient members and tensioned thereby.

WILLIAM H. SCHNEIDER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 789,044 Mentzer May 2, 1905 798,695 Oehrle Sept. 5, 1905 1,398,243 Rosskopf Nov. 29, 1921 1,127,802 Palmer Feb. 9, 1915

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