CN203260234U - Circle circumference formula derivation instrument - Google Patents
Circle circumference formula derivation instrument Download PDFInfo
- Publication number
- CN203260234U CN203260234U CN 201320116305 CN201320116305U CN203260234U CN 203260234 U CN203260234 U CN 203260234U CN 201320116305 CN201320116305 CN 201320116305 CN 201320116305 U CN201320116305 U CN 201320116305U CN 203260234 U CN203260234 U CN 203260234U
- Authority
- CN
- China
- Prior art keywords
- circle
- box body
- disc
- circular box
- girth
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
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- Drawing Aids And Blackboards (AREA)
Abstract
The utility model discloses a circle circumference formula derivation instrument, which is composed of a circular box body and a disc with a 10-centimeter diameter. The circumferential wall of the circular box body is provided with an opening 1. A circular box body diameter strip PQ which can rotate for 90 degrees with a P point as the circle center is arranged on the box cover corresponding to the opening. The circle centers on the upper box cover and the lower box cover of the circular box body are both provided with a recessed hole 5. A radius drawn in advance is arranged on the disc. A fixed shaft 7 with no rotation is arranged on the circle center of the disc. The two ends of the shaft are right located inside the recessed holes of the circular box body. One end of a steel ruler 2 with a 31.4-centimeter length is fixed on the circumference of the disc. The other end of the steel ruler is exposed outside the box body from the opening 1 of the circular box body. The circle circumference formula derivation instrument can be used for demonstrating and deriving the circle circumference formula.
Description
Technical field:
The utility model and a kind of school mathematics instruments used for education, particularly round girth derivation of equation instrument.
Background technology:
When middle and primary schools impart knowledge to students the girth formula of justifying at present, all be to roll a week at ruler with a disk, then draw round girth formula by computational data.It is cumbersome to operate, and can not play effect directly perceived.The utility model successful directly perceived uses the round girth formula of its demonstration derivation, and the student is acceptant.
Summary of the invention:
The technical problems to be solved in the utility model provides a kind of with low cost, and is simple in structure, the girth derivation of equation instrument of easy to operate circle.
For solving the problems of the technologies described above, the disk dish that the utility model is 10cm by a transparent round box and diameter forms.
Round box be two halves altogether, its circle centre position has shrinkage pool (5), and an opening part (1) is arranged on the circumference.Covered a diameter bar PQ (3) on the box body, P point place is fixed, and can clockwise rotate 90 ° along the P point.
The circle centre position of disk dish penetrates one and maintains static moving axle (7), and the radius (6) of finishing in advance in addition on the disk dish is fixed a steel ruler bar (2) on the right circumference of its radius,
The length of steel ruler bar is the girth of disk dish, is again 3.14 times of diameter.Chi end at the steel ruler bar works the scale that is decorated with 3 diameter lengths.
The disk dish is packed in the round box, and two terminations of disk dish circle centre position stationary shaft are just in time dropped in the shrinkage pool of round box.Another chi end of steel ruler exposes from the circumferential opening of round box.The radius of finishing in advance on the disk dish just in time with round box on finish in advance diameter overlap.
After the steel ruler bar is all pulled out in the round box, the radius on the disk dish can also with round box on diameter overlap.
Description of drawings:
Fig. 1 is structural representation of the present utility model, the opening part of 1 round box wherein, 2 steel rulers, the diameter bar PQ on 3 round boxs, the fixedly termination of 4 steel ruler bars, the shrinkage pool on 5 round boxs, the radius on the 6 disk dishes, 7 stationary shaft.
Embodiment:
Below by way of embodiments and drawings the utility model is further elaborated, referring to accompanying drawing 1, the disk dish that the utility model is 10cm by a transparent round box and diameter forms.
One opening part is arranged on the circumference of round box, cover at the right box body in opening place a rotary diameter bar PQ is installed.
The radius of finishing is in advance arranged on the disk dish, the steel ruler that to fix a length at the intersection point place of radius and circumference be 31.4cm, circle centre position penetrates one and maintains static moving axle.The disk dish is put into box body, and the chi end exposes outside the round box from the opening part of box body.
During use, put down the diameter bar that covers on the box body, the steel ruler bar is pulled out in box body slowly, can find out intuitively that round girth is 3.14 times of diameter, thereby draw round girth formula: C=π d.
Claims (3)
1. the girth derivation of equation instrument of circle comprises round box and disk dish, it is characterized in that the disk dish is in round box.
2. the girth derivation of equation instrument of circle according to claim 1 is characterized in that the upper lower casing circle centre position of round box has shrinkage pool, on covered a diameter bar, an opening part is arranged on the circle wall.
3. the girth derivation of equation instrument of circle claimed in claim 1 is characterized in that a radius of finishing is in advance arranged above the disk dish, and a stationary shaft passes from circle centre position, fixes a steel ruler bar on the circumference.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320116305 CN203260234U (en) | 2013-03-07 | 2013-03-07 | Circle circumference formula derivation instrument |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201320116305 CN203260234U (en) | 2013-03-07 | 2013-03-07 | Circle circumference formula derivation instrument |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203260234U true CN203260234U (en) | 2013-10-30 |
Family
ID=49472780
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201320116305 Expired - Fee Related CN203260234U (en) | 2013-03-07 | 2013-03-07 | Circle circumference formula derivation instrument |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN203260234U (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104036673A (en) * | 2013-03-07 | 2014-09-10 | 周维保 | Circle circumference formula derivation instrument |
-
2013
- 2013-03-07 CN CN 201320116305 patent/CN203260234U/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104036673A (en) * | 2013-03-07 | 2014-09-10 | 周维保 | Circle circumference formula derivation instrument |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20131030 Termination date: 20140307 |