CN104036673A - Circle circumference formula derivation instrument - Google Patents
Circle circumference formula derivation instrument Download PDFInfo
- Publication number
- CN104036673A CN104036673A CN201310081678.2A CN201310081678A CN104036673A CN 104036673 A CN104036673 A CN 104036673A CN 201310081678 A CN201310081678 A CN 201310081678A CN 104036673 A CN104036673 A CN 104036673A
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- CN
- China
- Prior art keywords
- box body
- circle
- disc
- circular box
- opening
- 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.)
- Pending
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- Drawing Aids And Blackboards (AREA)
Abstract
The invention discloses a circle circumference formula derivation instrument. The circle circumference formula derivation instrument 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 by taking a P point as a circle center is arranged above a 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 each provided with a recessed hole 5. A radius OA drawn in advance is arranged on the disc. A fixed shaft 7 with no rotation is arranged at the circle center of the disc. The two end heads of the shaft are right located inside the recessed holes of the circular box body. The end head of one end of a steel ruler 2 with a length of 31.4 centimeters is fixed at an A point of the circumference of the disc, and the end head of the other end of the steel ruler is exposed outside the box body from the opening 1 of the circular box body.
Description
Technical field:
The present invention relates to 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, be all on ruler, to roll one week with a disk, then by computational data, draw round girth formula.Operate cumbersome, can not play effect directly perceived.The present invention's successful directly perceived, is used the round girth formula of its demonstration derivation, and student is acceptant.
Summary of the invention:
The technical problem to be solved in the present invention is to provide a kind of with low cost, 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 (Fig. 2) that the present invention is 10cm by a transparent round box (Fig. 1) and diameter forms.
Round box be two halves altogether, its circle centre position has shrinkage pool (5), has an opening part (1) on circumference.On box body, covered a diameter bar PQ (3), P point place is fixed, and can rotate 90 ° along P point.
The circle centre position of disk dish is worn one of people and is maintained static moving axle (7), the radius OA (6) finishing in advance in addition on disk dish, and a steel ruler (2) is fixed at A point place, and its length is the girth of disk dish, is again 3.14 times of diameter.Chi end at steel ruler bar works the scale that is decorated with 3 diameter lengths.
Disk dish packs in 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 disk dish just in time with round box on diameter overlap.
Steel ruler is all pulled out in round box, the radius on disk dish can also with round box on diameter overlap.
Accompanying drawing explanation:
Fig. 1 is the structural representation of round box, 1 opening part wherein, 2 steel rulers, 3 diameter bar PQ, 5 shrinkage pools.
Embodiment:
The present invention is further elaborated below by way of embodiments and drawings, and the disk dish that is 10cm by a transparent round box and diameter referring to accompanying drawing 1,2 the present invention forms.
On the circumference of round box, have an opening part, opening place right on cover a rotary diameter bar PQ be installed.
On disk dish, have the radius OA finishing in advance, the steel ruler that a length is 31.4cm is fixed at A point place, and circle centre position is worn people one and maintained static moving axle.Disk dish is put into box body, and chi end exposes round box from the opening part of box body.
During use, put down the diameter bar covering on box body, steel ruler is slowly pulled out in box body, can intuitively find out 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 disk dish is in round box.
2. round box claimed in claim 1, is characterized in that the upper lower casing circle centre position of box body has shrinkage pool, has above covered a diameter bar, has an opening part in circumferential wall.
3. disk dish claimed in claim 1, is characterized in that there is a radius OA who finishes in advance above, and circle centre position has an axle to pass, and a steel ruler is fixed at circumference A point place.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310081678.2A CN104036673A (en) | 2013-03-07 | 2013-03-07 | Circle circumference formula derivation instrument |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310081678.2A CN104036673A (en) | 2013-03-07 | 2013-03-07 | Circle circumference formula derivation instrument |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN104036673A true CN104036673A (en) | 2014-09-10 |
Family
ID=51467426
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201310081678.2A Pending CN104036673A (en) | 2013-03-07 | 2013-03-07 | Circle circumference formula derivation instrument |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN104036673A (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5215467A (en) * | 1992-01-27 | 1993-06-01 | Brischke Donald A | Mathematical instruction board and method of use |
| CN2302498Y (en) * | 1997-06-12 | 1998-12-30 | 周维保 | Multi-function measuring instrument |
| CN2484609Y (en) * | 2001-05-31 | 2002-04-03 | 魏学谦 | Disc instrument for geometry teaching |
| CN201637369U (en) * | 2009-09-26 | 2010-11-17 | 于书霞 | Circumference measuring scale |
| CN102394019A (en) * | 2011-12-16 | 2012-03-28 | 张启士 | Circumference ratio demonstrator for mathematics in primary schools |
| KR20120110281A (en) * | 2011-03-29 | 2012-10-10 | 공주대학교 산학협력단 | The teaching tools which studies the carbon dioxide absorption degree of the tree |
| CN203260234U (en) * | 2013-03-07 | 2013-10-30 | 周维保 | Circle circumference formula derivation instrument |
-
2013
- 2013-03-07 CN CN201310081678.2A patent/CN104036673A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5215467A (en) * | 1992-01-27 | 1993-06-01 | Brischke Donald A | Mathematical instruction board and method of use |
| CN2302498Y (en) * | 1997-06-12 | 1998-12-30 | 周维保 | Multi-function measuring instrument |
| CN2484609Y (en) * | 2001-05-31 | 2002-04-03 | 魏学谦 | Disc instrument for geometry teaching |
| CN201637369U (en) * | 2009-09-26 | 2010-11-17 | 于书霞 | Circumference measuring scale |
| KR20120110281A (en) * | 2011-03-29 | 2012-10-10 | 공주대학교 산학협력단 | The teaching tools which studies the carbon dioxide absorption degree of the tree |
| CN102394019A (en) * | 2011-12-16 | 2012-03-28 | 张启士 | Circumference ratio demonstrator for mathematics in primary schools |
| CN203260234U (en) * | 2013-03-07 | 2013-10-30 | 周维保 | Circle circumference formula derivation instrument |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Application publication date: 20140910 |