Oval scale
Technical field
The utility model relates to a kind of graphic plotting instrument, particularly, relates to a kind of oval scale.
Background technology
Ellipse is a kind of common geometric figure, at industry-by-industry application is arranged all.Drawing ellipse is the thing of a trouble, though a kind of ellipsograph is arranged now, be fully feasible in theory, but practical operation is got up but very inconvenient, and in actual applications, often do not need or and do not know standard elliptic, and only be to need a kind of more satisfactory figures.Particularly, the ellipse on the project blue print often is not an ellipse truly, but diameter of a circle is only known in the projection of circle, and does not know oval major and minor axis, and this moment, ellipsograph just can't be used at all.
Drawing at present the easiest oval method is " four heart circule methods ", and as shown in Figures 1 to 3, it is applicable to the round survey technique of painting that just waits, promptly replaces elliptic arc approx with four arcs, and step is as follows:
1) draw axonometric projection---the rhombus of round circumscribed square, and determine four centers of circle, as figure
2Shown in: wherein two of short diagonal end points are two center of circle O
1, O
2They are to the line O of opposite side mid point
1A
1, O
1D
1(O
2B
1, O
2C
1) with the intersection point O of long-diagonal
3, O
4Be two other center of circle.
2) respectively with O
1, O
2Be the center of circle, O
1A
1For radius is drawn orthodrome A
1D
1And B
1C
1With O
3, O
4Be the center of circle, O
3A
1For radius is drawn roundlet arc A
1B
1And D
1C
1, as shown in Figure 3.
Obviously, it was both more convenient and swift than additive method to draw ellipse in this way, accurately level and smooth again, but drew rhombus and definite center of circle O
3, O
4With still more time-consuming thing such as each point of contact (mid point), and be difficult for grasping toward contact for the beginner, especially for the technique of painting of fillet, easier makeing mistakes.
Therefore, in view of the above problems, need a kind of aid that above-mentioned " four heart circule methods " draws ellipse of using.
The utility model content
The purpose of this utility model provides a kind of oval scale, and to address the above problem, this oval scale can be used " four heart circule methods " quickly and easily and draw oval.
Above-mentioned purpose is achieved through the following technical solutions: oval scale, comprise main scale, this main scale comprises the angle square of two 60 ° of fixed angles of symmetry, be respectively equipped with chute on each angle square, two described angle squares connect respectively by two slidiing pins accordingly, this slidiing pin can be free to slide along described chute, an end that is fixedly connected on active connection in the described slidiing pin, the other end of this active connection is provided with rotary pin shaft, the center of this rotary pin shaft is corresponding to the intersection point on the measurement limit of two described angle squares, and can be connected with the rotation chi on this rotary pin shaft, this rotation chi is provided with serrate slot.
By rotation chi of the present utility model, can determine rapidly and accurately to draw each the oval key point and the direction of axonometric axis, thereby it is oval to adopt " four heart circule methods " to draw quickly and easily.In addition, oval scale of the present utility model is simple in structure, and is with low cost, easy to use, has stronger practicality and good technical economic benefit.
Description of drawings
Fig. 1 to Fig. 3 is the drawing process schematic diagram that is used to draw oval " four heart circule methods ";
Fig. 4 is the structural representation of the oval scale of the utility model specific embodiment;
Fig. 5 to Fig. 7 draws oval application principle schematic diagram by means of oval scale of the present utility model.
Among the figure: 1 main scale; 2 rotation chis; 3 active connections; 4 slidiing pins; 5 chutes; 6 serrate slots; 7 rotary pin shafts.
The specific embodiment
The specific embodiment of the utility model oval scale is described below in conjunction with accompanying drawing.
As shown in Figure 4.This oval scale comprises main scale 1, this main scale 1 comprises the angle square of two 60 ° of fixed angles of symmetry, be respectively equipped with chute 5 on each angle square, two described angle squares connect respectively by two slidiing pins 4 accordingly, this slidiing pin 4 can be free to slide along described chute, apparently, remains two angle square symmetries during slip, four limits of such two angle squares promptly constitute a rhombus, and the length of side of rhombus is diameter of a circle; The mid point on each limit is A shown in Figure 2
1, B
1And D
1, C
1The intersection point on the measurement limit of two angle squares is O shown in Figure 2
1And O
2The point.A slidiing pin in the described slidiing pin 4 is fixedly connected on an end of active connection 3, the other end of this active connection 3 is provided with rotary pin shaft 7, the center of this rotary pin shaft 7 promptly is equivalent to O shown in Figure 2 corresponding to the intersection point on the measurement limit of two described angle squares
1Point, and be connected with rotation chi 2 on this rotary pin shaft 7, promptly rotating chi 2 can be around rotary pin shaft 7 rotation, and this rotation chi 2 is provided with serrate slot 6, and the serrate slot 6 on rotation chi 2 is aimed at the mid point A on the limit of above-mentioned rhombus
1And D
1The time, the intersection point of the long-diagonal of it and described rhombus is O
3And O
4, on drawing paper, mark this position.
Penholder is gone into A
1In the serrate slot at place, promptly can O
1Be the center of circle, O
1A
1For radius is drawn orthodrome A
1D
1Conversely, promptly can O
2Be the center of circle, O
2B
1For radius is drawn orthodrome B
1C
1As for little arc A
1B
1And D
1C
1Can draw by means of compasses, also the rotation chi can be taken off, and an end points is individually fixed in O
3And O
4And draw with the rotation chi.
The main purpose of this chi is in order to determine A shown in Figure 2 fast
1, B
1, D
1, C
1Point and O
1, O
2, O
3, O
4Point after these points are determined, can be drawn each section circular arc by means of compasses.Certainly, this chi also can help to determine fast the direction of each axonometric axis of isometric drawing.The point of contact and the center of circle of determining the isometric drawing of all directions fillet by means of this chi have more superiority, and its principle such as Fig. 4 are to shown in Figure 7.
By last description as seen, by rotation chi of the present utility model, can determine rapidly and accurately to draw oval each key point and axonometric axis direction, thereby it is oval to adopt " four heart circule methods " to draw quickly and easily.In addition, oval scale of the present utility model is simple in structure, and is with low cost, easy to use, has stronger practicality and good technical economic benefit, thereby for oval a kind of simple and efficient instrument that provides is provided on the engineering.
Each concrete technical characterictic described in the above-mentioned specific embodiment can make up arbitrarily by any suitable manner, and it falls within the scope disclosed in the utility model equally.Simultaneously, also can make up arbitrarily between the various embodiment of the present utility model, as long as it is without prejudice to thought of the present utility model, it should be considered as content disclosed in the utility model equally.In addition; the utility model is not limited to the detail in the above-mentioned embodiment; in technical conceive scope of the present utility model, can carry out multiple simple variant to the technical solution of the utility model, these simple variant all belong to protection domain of the present utility model.Protection domain of the present utility model is defined by the claims.