CN216927858U

CN216927858U - Triangle cosine theorem demonstrator

Info

Publication number: CN216927858U
Application number: CN202122903809.3U
Authority: CN
Inventors: 万卓函
Original assignee: Individual
Current assignee: Individual
Priority date: 2021-11-24
Filing date: 2021-11-24
Publication date: 2022-07-08
Anticipated expiration: 2031-11-24

Abstract

The utility model relates to the field of teaching appliances, and discloses a triangle cosine theorem demonstrator which comprises a first graduated scale, a second graduated scale, a first sliding chute, a second sliding chute, a protractor, a rotating shaft, a first sliding pin, a second sliding pin and a plastic leather strip rope, wherein the first sliding chute is arranged on the first graduated scale, and the first sliding pin is arranged on the first sliding chute; the first graduated scale and the second graduated scale are rotationally connected through a rotating shaft, a second sliding groove is formed in the second graduated scale, and a second sliding pin is arranged on the second sliding groove; the plastic leather strip rope is connected with the first sliding pin and the second sliding pin; the middle point of the protractor is fixed at the intersection of the middle lines of the first scale and the second scale. The method has the advantages of convenient operation and reading, and more intuitive and effective understanding of the relation between the three sides and the angle of the triangle; the first graduated scale and the second graduated scale are flexible to rotate, and the angle setting of 0-180 degrees meets the teaching requirement.

Description

Triangle cosine theorem demonstrator

Technical Field

The utility model relates to the field of teaching appliances, in particular to a triangle cosine theorem demonstrator.

Background

The cosine theorem is a mathematical theorem describing the cosine value relationship between the length of three sides in a triangle and an angle, and is a popularization of the pythagorean theorem in the case of a general triangle, and the pythagorean theorem is a special case of the cosine theorem. The cosine theorem is an important theorem for revealing the corner relationship of a triangle, the problem that the third side is solved by using two sides and included angles of a known triangle or the problem that the triangle is solved by using three known sides can be solved by directly using the cosine theorem, and if the cosine theorem is deformed and is properly moved to other knowledge, the use is more convenient and flexible. However, the cosine law is a difficult point, and the teaching process is often abstract due to the fact that no specific demonstration tool is available.

The disclosure No. CN206301520U discloses a cosine theorem demonstration device, which belongs to the technical field of teaching instrument equipment and comprises a frame body, wherein the frame body consists of a triangular frame body and a protractor, the triangular frame body comprises a first frame rod, a second frame rod, a third frame rod and a fourth frame rod, and a second guide rail groove, a third guide rail groove and a fourth guide rail groove on the frame rods can slide and stretch by taking a first shaft connecting point as an axis, so that the degrees of three angles on the triangular frame body are changed; the method has the advantages that the mutual relation between the edges and the angles in the cosine determination is made into a structural device which can be directly observed, the lengths of the two edges, the size of the angles of the three angles and the length of the vertical line on the triangular frame body can be changed by sliding the rotating shaft on the first shaft connecting point, and the conversion relation between the angles and the lengths can be directly observed. However, the device is inconvenient to operate, complex to use and not suitable for demonstration in class.

SUMMERY OF THE UTILITY MODEL

In order to solve the technical problems, the utility model provides a demonstration teaching aid for the cosine theorem, which can freely move a graduated scale and a plastic leather strip rope to read corresponding scales, observe the angle of a formed triangle through a protractor, and accurately and conveniently discover the mutual influence relation between the length of three sides of the triangle and one corner of the triangle by fixing and regularly changing the three sides of the triangle, so that a teacher can intuitively and effectively teach the knowledge of the cosine theorem, the understanding of students on the cosine theorem is improved, and the demonstration teaching aid has the characteristics of simple operation and easy implementation.

The specific technical scheme of the utility model is as follows: a triangle cosine theorem demonstrator is characterized in that: the plastic leather strap rope comprises a first graduated scale, a second graduated scale, a first sliding groove, a second sliding groove, a protractor, a rotating shaft, a first sliding pin, a second sliding pin and a plastic leather strap rope, wherein the first sliding groove is formed in the first graduated scale, and the first sliding pin is formed in the first sliding groove; the first graduated scale and the second graduated scale are rotationally connected through a rotating shaft, a second sliding groove is formed in the second graduated scale, and a second sliding pin is arranged on the second sliding groove; the plastic leather strip rope is connected with the first sliding pin and the second sliding pin; the middle point of the protractor is fixed at the intersection of the middle lines of the first scale and the second scale.

The triangle cosine theorem demonstrator has a first chute in the middle of a first scale, a second chute in the middle of a second scale, the lower part of a protractor is fixed with the left side of the first scale, the first scale and the second scale are connected through a rotating shaft, the second scale can rotate on the first scale through the rotating shaft, and an included angle between the first scale and the second scale is read through the protractor. The first sliding pin can freely move and be fixed in the first sliding groove, the second sliding pin can freely move and be fixed in the second sliding groove, the plastic leather strip rope with scales is connected with the first sliding pin and the second sliding pin, one end of the plastic leather strip rope is connected with the second sliding pin and is fixed, the other end of the plastic leather strip rope can be separated from the first sliding pin, and when the angle gauge is used, the angle gauge only needs to be tensioned and then fixed on the sliding pin, so that the length of the bevel edge corresponding to the angle where the angle gauge is located can be read. The second graduated scale can rotate through the rotation axis, and when the second graduated scale and the first graduated scale form any angle, the third telescopic length represented by the plastic leather strip rope with the graduation is combined to represent the third side of the triangle, but the plastic leather strip rope does not have elasticity. The middle point of the protractor is fixed at the intersection point of the central lines of the first graduated scale and the second graduated scale, so that the accuracy of angle measurement can be guaranteed. The second graduated scale can rotate through the rotation axis, conveniently carries when coinciding with first graduated scale, and the sliding pin can remove through the spout, changes triangle-shaped length of side to directly read out third edge length of side through the little leather strap rope of taking the scale.

Preferably, the first sliding pin comprises a first sliding pin main body, a first fixing bolt and a first slideway, the first slideway is embedded in the first sliding groove and is fixed in a sliding manner, and the first fixing bolt movably penetrates through the first sliding pin main body and is fixed to abut against the back face of the first sliding groove; a plastic leather strap rope is arranged between the first sliding pin main body and the front face of the first sliding groove, and the other end of the plastic leather strap rope is fixedly connected with the second sliding pin.

The first sliding groove and the first sliding pin main body can be compressed tightly in the process of fixing bolt reinforcement, so that the first sliding pin is fixed, the plastic leather strap rope is arranged between the front face of the first sliding pin main body and the front face of the first sliding groove, when the first sliding groove and the sliding pin main body are compressed tightly by the first fixing bolt, the fixing bolt movably penetrates through the first sliding pin main body to abut against the back face of the first sliding groove during tightening, the friction force between the first sliding pin main body and the front face of the first sliding groove is increased, fixation is achieved, the plastic leather strap rope on the front face of the first sliding pin main body and the front face of the first sliding groove can be fixed simultaneously, and the plastic leather strap rope is arranged on the front face of the first sliding pin main body and the front face of the first sliding groove to facilitate reading in the demonstration process. The front side refers to the side facing the demonstration object, namely the student, and the back side refers to the side facing away from the demonstration object when the triangle cosine theorem demonstrator demonstrates.

Preferably, the second sliding pin is fixed in the second sliding groove in a sliding manner, the second sliding pin comprises a second sliding pin main body, a second fixing bolt and a second slide way, the slide way is embedded in the second sliding groove and fixed in a sliding manner, and the second fixing bolt movably penetrates through the second sliding pin main body and abuts against any surface of the second scale.

In order to meet the requirements of different triangular three-side relationships, the first sliding pin can freely move and be fixed in the first sliding groove; the second sliding pin can freely move and be fixed in the second sliding groove. Plastics leather strap rope one end is fixed, and other end swing joint is fixed in first sliding pin, and the first sliding pin of optional plastics leather strap rope one end fixed connection second in this scheme, the first sliding pin of other one end swing joint.

Preferably, the plastic leather strip rope is provided with scales.

Preferably, the 0 ° scale line of the protractor is parallel to the scale line of the first scale, and the protractor is fixed to the first scale.

In order to ensure that data is convenient to read, the 0-degree scale line of the protractor is parallel to the scale line of the first graduated scale, namely parallel to the reading change direction of the scale line.

Preferably, the 180 ° scale line of the protractor is parallel to the scale line of the second scale, and the protractor is fixed to the second scale.

Preferably, the rotation angle between the first scale and the second scale is 0-180 °.

Compared with the prior art, the utility model has the beneficial effects that:

1. the operation and reading are convenient, the carrying is convenient, the cosine theorem can be intuitively and effectively understood, and the relation between the angle and the length change of the three sides is convenient to observe;

2. the length and the proportion of the three sides, the adjustable range of 0-180 degrees between the first graduated scale and the second graduated scale meet the teaching requirement, and the operation of the adjusting process is simple.

Drawings

FIG. 1 is a schematic diagram of an embodiment of the present invention.

FIG. 2 is a schematic view of a fixing structure between the second slide pin and the second slide slot;

fig. 3 is a schematic view of a fixing structure between the first sliding pin and the first sliding groove.

The reference signs are:

1. the first scale, 2, the second scale, 3, the protractor, 4, the first chute, 5, the second chute, 6, the rotating shaft, 7, the first sliding pin, 71, the first sliding pin main body, 72, the first fixing bolt, 73, the first slideway, 8, the second sliding pin, 81, the second sliding pin main body, 82, the second fixing bolt, 83, the second slideway, and 9, the plastic leather strap rope.

Detailed Description

The present invention will be further described with reference to the following examples. The devices, connections, and methods referred to in this disclosure are those known in the art, unless otherwise indicated.

Example 1

As shown in fig. 1: a triangle cosine theorem demonstrator comprises a first graduated scale 1, a second graduated scale 2, a first chute 4, a second chute 5, a protractor 3, a rotating shaft 6, a first sliding pin 7, a second sliding pin 8 and a plastic leather strip rope 9, wherein the first chute 4 is arranged on the first graduated scale 1, and the first sliding pin 7 is arranged on the first chute 4; the first graduated scale 1 and the second graduated scale 2 are rotatably connected through a rotating shaft 6, a second chute 5 is arranged on the second graduated scale 2, and a second sliding pin 8 is arranged on the second chute 5; the plastic leather strip rope 9 is connected with the first sliding pin 7 and the second sliding pin 8; the middle point of the protractor 3 is fixed at the intersection point of the central lines of the first graduated scale 1 and the second graduated scale 2; the first sliding pin 7 can be fixed in the first sliding groove 4 in a sliding manner; the second sliding pin 8 can be fixed in the second sliding groove 5 in a sliding manner; one end of the plastic leather strip rope 9 is fixedly connected with the second sliding pin 8, and the other end of the plastic leather strip rope is movably connected with the first sliding pin 7; the plastic leather strip rope 9 is provided with scales; the 30-degree scale line of the protractor is parallel to the scale part of the first graduated scale 1; the protractor 3 is fixed on the first graduated scale 1; the rotation angle between the first scale 1 and the second scale 2 is 0-180 °.

As can be seen from fig. 2, the plastic leather strap 9 is fixed to the second sliding pin main body 81, and the second sliding pin main body 81 and the second sliding chute 5 can be pressed by tightening the second fixing bolt 82, and the second sliding chute 5 is embedded in the slideway 73.

As shown in fig. 3, the basic structure is similar to that of fig. 2, except that the plastic leather strap rope 9 is located between the first sliding pin main body 71 and the first sliding groove 4, and during tightening of the fastening bolt, the first sliding groove 4 presses the first sliding pin main body 71, and simultaneously fixes the plastic leather strap rope 9.

When measuring the edge, according to needs, the second scale 2 can be rotated to a needed angle around the rotating shaft 6, the second sliding pin 8 slides on the second slide rail 83 to a needed length and then is fixed through the second fixing bolt 82, the first sliding pin 7 slides later, the first sliding pin 7 can slide on the first slide rail 73, the plastic leather strip rope 9 is loosened in the process, the plastic leather strip rope 9 can slide between the first sliding pin main body 71 and the first slide groove 4, the plastic leather strip rope 9 is tightened after the needed length is reached, the first sliding pin 7 is fixed, meanwhile, the plastic leather strip rope 9 is also fixed, and the third edge length can be obtained through reading.

When the angle is measured, the second sliding pin 8 can be slid to the required length and then fixed through the second fixing bolt 82 according to the requirement, the first sliding pin 7 is then slid to the required length, the plastic leather strip rope 9 is adjusted to the required length at the moment, the rotating shaft 6 is adjusted to strain the plastic leather strip rope 9 after the first sliding pin 7 and the plastic leather strip rope 9 are fixed, and the corresponding angle can be obtained by reading the angle gauge 3.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and all simple modifications, changes and equivalent structural changes made to the above embodiment according to the technical spirit of the present invention still belong to the protection scope of the technical solution of the present invention.

Claims

1. A triangle cosine theorem demonstrator is characterized in that: the plastic rubber belt leather strip angle gauge comprises a first graduated scale (1), a second graduated scale (2), a first sliding chute (4), a second sliding chute (5), an angle gauge (3), a rotating shaft (6), a first sliding pin (7), a second sliding pin (8) and a plastic rubber belt rope (9), wherein the first sliding chute (4) is arranged on the first graduated scale (1), and the first sliding pin (7) is arranged on the first sliding chute (4); the first graduated scale (1) is rotatably connected with the second graduated scale (2) through a rotating shaft (6), a second chute (5) is formed in the second graduated scale (2), and a second sliding pin (8) is arranged on the second chute (5); the plastic leather strip rope (9) is connected with the first sliding pin (7) and the second sliding pin (8); the middle point of the protractor (3) is fixed at the intersection of the central lines of the first graduated scale (1) and the second graduated scale (2).

2. The triangle cosine theorem demonstrator of claim 1, wherein the first sliding pin (7) comprises a first sliding pin body (71), a first fixing bolt (72) and a first sliding way (73), the first sliding way (73) is embedded in the first sliding slot (4) to be fixed in a sliding manner, and the first fixing bolt (72) movably penetrates through the first sliding pin body (71) to abut against the back surface of the first sliding slot (4).

3. The triangle cosine theorem demonstrator of claim 2, wherein a plastic leather strap rope (9) is arranged between the first sliding pin main body (71) and the front surface of the first sliding chute (4), and the other end of the plastic leather strap rope (9) is fixedly connected with the second sliding pin (8).

4. The triangle cosine theorem demonstrator of claim 3, wherein the second sliding pin (8) is fixed in the second sliding slot (5) in a sliding manner, the second sliding pin (8) comprises a second sliding pin body (81), a second fixing bolt (82) and a second slideway (83), the slideway (83) is embedded in the second sliding slot (5) and fixed in a sliding manner, and the second fixing bolt (82) movably penetrates through the second sliding pin body (81) to abut against any surface of the second scale (2).

5. The triangle cosine theorem demonstrator of claim 1, wherein said plastic leather strip string (9) is provided with graduations.

6. The triangle cosine theorem demonstrator according to claim 1, wherein the 0 ° graduation marks of said protractor (3) are parallel to the graduation marks of the first graduated scale (1).

7. The triangle cosine theorem demonstrator according to claim 6, wherein said protractor (3) is fixed to the first graduated scale (1).

8. The triangle cosine theorem demonstrator according to claim 1, wherein the 180 ° graduation marks of said protractor (3) are parallel to the graduation marks of said second graduated scale (2).

9. The triangle cosine theorem demonstrator according to claim 8, wherein said protractor (3) is fixed to the second scale (2).

10. The triangle cosine theorem demonstrator according to claim 1, wherein the rotation angle between said first scale (1) and said second scale (2) is between 0 ° and 180 °.