CN201693928U - Rotary protractor - Google Patents

Abstract

The utility model provides a rotary protractor, which comprises two same protractors, wherein the two protractors are vertically overlapped and are coaxially fixed at the center of a circle. The two protractors can rotate around the center of a fixed shaft, and the two protractors can be used for drawing a straight line when being overlapped, and can measure and directly draw an accurate angle when being opened. The rotary protractor can be flexibly rotated so as to directly draw accurate angles, and can be more conveniently used than the ordinary protractor.

Description

The rotation amount hornwork

Technical field

The utility model relates to a kind of rotation amount hornwork.

Background technology

Protractor is one of learning tool of primary and secondary students' indispensability.When last mathematics class, need ruler to draw straight line sometimes, requirement hornwork measuring angle so all will use these instruments every day, fails to lay down again in the pencil box but be with many sometimes.Common protractor can only take measurement of an angle, and when needs picture angle, an other limit is drawn after having measured angle again in the limit of can only drawing earlier, and protractor is divided into outer semi arch and has the interior semi arch of scale, has error when taking measurement of an angle, and is not very accurate.

Summary of the invention

The technical problems to be solved in the utility model provides a kind of protractor of rotation, and it can be worked as ruler and use the angle accurately of directly measuring and draw again.

The technical solution of the utility model is: a kind of rotation amount hornwork, comprise two identical protractors, and described two identical protractors are stacked together up and down, and coaxial fixing at circle centre position.

Described two identical protractors are made up of common protractor.Circle centre position at two protractors is installed a fixed axis, and such two protractors can rotate around the axle center.

Protractor of the present utility model can not only be realized the function of ruler, and the energy measurement and the angle of drawing, and has reduced the quantity of required stationery for the student.Compare with common protractor, the protractor of the present utility model required angle of can directly drawing, very easy to use.

Description of drawings

Fig. 1 is the structure of rotation amount hornwork of the present utility model.

The specific embodiment

Below in conjunction with drawings and Examples the utility model structure is described in further detail.

As shown in Figure 1, the rotation amount hornwork comprises two identical protractors 1 and 2, and wherein protractor 1 overlays on the protractor 2.Circle centre position in protractor 1 and 2 uses a nail 3 as fixed axis.After two protractors are fixed, can overlapping placement use as ruler, also can rotate the measurement of carrying out angle relatively.Two protractors rotation angle separately is the diagonal angle with the angle of measurement, equates, so the limit of two protractors needed angle of directly drawing about can utilizing.

Wherein, the center of circle of two protractors can also use other object as fixed axis, as rivet etc.

Claims (1)

1. a rotation amount hornwork comprises two identical protractors, it is characterized in that: described two identical protractors are stacked together up and down, and coaxial fixing at circle centre position.

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