Multifunctional compasses

Abstract

The invention discloses a pair of multifunctional compasses. On the basis of a current compass structure (P), the pair of multifunctional compasses is characterized in that an arc scale plate (F) which separately shows angle indication scales (t) and length indication scales (u) is arranged on one compass leg (3); besides, the arc center of the arc scale plate (F) coincides with a central shaft (2) at the end parts of two compass legs (3); the distances from the central shaft (2) of the compasses (P) to two pin points (4) are identical; the intervals of the length indication scales (u) on the arc scale plate (F) are constrained by the identical distances; the intervals of the angle indication scales (t) are identical, and are determined according to the scales of a conventional protractor; and the intervals of the length indication scales (u) are determined according to an integrated cosine law, are unequal, and are constrained by the distances from the pair of pin points (4) to the central shaft (2). The technique is crucially characterized in that the cosine law that c<2> equals a<2> plus b<2> minus 2abcosC is integrated into a more practical equation, namely, c<2> equals 2b<2>(1 minus cosC), and design and use of the compasses are directed by the latter equation.

Description

technical field [0001] The invention relates to compass technology, in particular to a multifunctional compass technology capable of measuring both angle and length. [0002] technical background [0003] At present, most of the compasses on the market have a single structure and can only realize the function of drawing a circle, and the radius of the drawn circle often needs to be obtained with the help of other rulers. [0004] CN204820798U discloses a kind of structural concept of multi-purpose compass: can't realize the multi-purpose compasses with true meaning according to this structural concept, for example, its arc scale does not provide key arc center position, and its length scale scale is equidistant again (See the schematic diagram of its accompanying drawing-should be unequal spacing according to the law of cosines), therefore, can't realize its expected requirement in use, promptly do not have practicability. Contents of the invention [0005] Purpose of the ...

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Problems solved by technology

[0003] At present, most of the compasses on the market have a single structure and can only realize the function of drawing a circle, and the radius of the drawn circle often needs to be obtained with the help of other rulers.

[0004] CN204820798U discloses a kind of structural concept of multi-purpose compass: can't realize the multi-purpose compasses with real meaning according to this structural concept, for example, its arc scale does not provide key arc center position, and its length scale scale is again equidistant (See the schematic diagram of its attached picture - according to the law of cosines, it should be unequal spacing), therefore, it cannot achieve its expected requirements during use, that is, it is not practical

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