JPH0630997B2 - Parabolic generator - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a parabolic creation tool that is suitable for use as a teaching material for geometry and the polishing of a parabolic surface.

Conventionally, some instruments that draw and form a parabola use a link mechanism or many gears.
These have the drawbacks of being complicated in construction, very difficult to manufacture, and difficult to operate.

The present invention has a main object to provide a parabolic creation tool that can draw an accurate parabola with a simple operation by using the principle of parabola different from the conventional one, which is easy to manufacture. is there.

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a schematic diagram showing an example of the present invention. Reference numeral 10 denotes a cross-shaped member, which is a first member 11 extending to a point N at which a normal line at an arbitrary point P of a parabola intersects the optical axis, and a focus F perpendicular to the first member 11 to a point PN. The second member 12 that coincides with the perpendicular line has a cross shape.

Then, along the center line of the first member 11, the sliding grooves 11a and 11b on which the first sliding member S ₁ and the second sliding member S ₂ slide.
And a slide groove 12a in which the third slider S ₃ and the fourth slider S ₄ slide along the center line of the second member 12.
And 12b are drilled. Sliding groove 1 of the first member 11
The first slider S ₁ that slides in 1a is rotatably supported by one end of a first link piece 14 that regulates the distance between the focal point F and an arbitrary point P, and also the first member. 11 sliding grooves 11
The second slider S ₂ sliding in b is rotatably supported by one end of the second link piece 15 that regulates the distance between the focal points F and N. The second link piece has the same length as the first link piece. The links 14 and 15 are provided to keep the distance between PF and FN constant. As shown in Fig. 2, parabolas have the characteristics and principles of ∠FP and ∠FNP.
It is understood that is always constant. The other end of the first link piece 14 is connected to the slide groove 12 of the second link piece 15.
The fourth slide piece S ₄ that fits into and slides on b is rotatably supported by the fourth slide piece S _4, and the other of the second link pieces 15 is also rotatably supported by the second slide piece S _2. There is. The third slider S ₃ is rotatably attached to the sixth slider S ₆ fitted in the lateral groove 32 with a fixing pin 17 longer than the thickness of the cross member 10 and the length of the groove plate 30. As a result, the cross member 10 moves freely around the focal point F.

The fifth slider S ₅ is further fitted into a vertical groove 31 formed on a line connecting an arbitrary point P and a foot M that descends from this point P in a direction perpendicular to the optical axis ON. As shown in FIG. 3, the vertical groove 31 is formed in the groove plate 30 together with the horizontal groove 32 formed on the optical axis connecting the focal points F and N to regulate the orthogonal relationship. A sixth slider S ₆ having a center coinciding with the axis of the third slider S ₃ is fitted and slid in the lateral groove 32. Then, as shown in FIG. 2, in order that the distance between the intersection points M and N perpendicular to the optical axis from an arbitrary point P is always 2f (f = focal length), the groove plate is placed on the point N. The fitting pin 33 of the slider S ₂ is planted on the 30. The groove plate 30 is restricted so as to move only in the intersecting axis direction.

It should be noted that, instead of the above-mentioned sliding groove and slider, a moving element such as rails and rolling elements and a moving element restricting portion can be used.

Next, the creation of a parabola using the above creation tool will be described.

First, as shown in FIG. 1, the fixing pin 17 is rotatably fixed to the drawing surface at a position to be the focal point F of the parabola A. In this state, a writing instrument such as a pencil or a pen, or a parabola generating means 18 such as a cutter is provided at an arbitrary point P, that is, the tip of the slider S ₁ , if desired. Then, the cross member 10 is focused on the focal point F.
By rotating to the right (or left) about
The movement of 0 is restricted only in the direction of the lateral groove 32, and the fifth slider S ₅ fitted to the first link piece 14, the second link piece 15 and the vertical groove 31 and the fifth slide piece fitted to the lateral groove 32. It is biased in the right (or left) direction in the drawing through the slider S 6 of No. ₆ .

In this case, an isosceles triangle connecting the arbitrary point P with the focal point F and the center point c of the cross-shaped member 10 and an isosceles triangle connecting N with the focal point F and the center point c of the cross-shaped member 10 have a congruent relationship. In order to maintain the distance, the distance between PF and FN is always equal, and the distance between the vertical groove 31 of the groove plate 30 and the pin 33 planted on the groove plate 30, that is, the line segment MN is constant (= 2f).
The parabola A has the property of parabola
Will be drawn.

As described above, according to the present invention, the cross member is formed by the first member and the second member which are orthogonal to each other, and the first member and the second member are formed.
Slipper restriction grooves are formed in the respective members, first and second sliders are fitted in the slider restriction grooves of the first member, and third and third sliders are fitted in the slider restriction grooves of the second member. Fit the 4 slides,
The one end and the first slider of the first link piece are rotatably supported, and the one end and the second slider of the second link piece having the same length as the first link piece are rotated. The other end of the first and second link pieces and the fourth slider, which is fitted into the slider restricting groove of the second member, are rotatably supported and rotatably supported by the groove plate. Two orthogonal first and second grooves are provided, a fifth slider is fitted in the first groove, and a sixth slider is fitted in the second groove,
The fifth slider is rotatably supported by the first slider, and the second slider is
A pin is planted on the extension line of the groove of No. 2, the pin and the second slide are rotatably supported, and the length is longer than the sum of the thickness of the sixth slide, the cross member and the groove plate. Since the third slide is rotatably supported, the number of constituent elements is much smaller than in the past, and the manufacturing is easy. Therefore, it is possible to form various lenses and mirror surfaces of a large-scale optical system. -It can be ground and cut, and when applied to teaching materials, it has very few components and is easy to manufacture, so it can be supplied at low cost.

[Brief description of drawings]

FIG. 1 is a front explanatory view showing an example of the creation tool of the present invention, FIG. 2 is an explanatory view for explaining a parabola, and FIG. 3 is a view showing an example of a groove plate. 10 ... Cross member, 11 ... First member, 12 ... Second member
Member, 13 ... Support shaft, 14 ... First link piece, 15 ...
... second link piece, 18 ... parabola generating means, 30 ...
Groove plate, 31 ... Vertical groove, 32 ... Horizontal groove, 33 ... Pin, A
...... Parabola, F ・ ・ ・ Focus, M ・ ・ ・ An intersection of a point P perpendicular to the optical axis, N ・ ・ ・ A point at which the normal line at an arbitrary point P intersects the optical axis, P ・ ・ ・ An arbitrary parabola point.

Claims (1)

[Claims] 1. A cross-shaped member is formed by a first member and a second member which are orthogonal to each other, and a slipper restricting groove is formed in each of the first member and the second member, and a slipper restricting groove of the first member is formed. The first and second sliders are fitted to the, the third and fourth sliders are fitted to the slider restricting grooves of the second member, and one end of the first link piece and the first The slider is rotatably supported, and one end of a second link piece having the same length as that of the first ring piece and the second link piece.
Rotatably rotatably supporting the other end of the first and second ring pieces and the fourth slider fitted in the slider restriction groove of the second member rotatably. , Two orthogonal first and second grooves are provided in the groove plate, a fifth slider is fitted in the first groove, and a sixth slider is fitted in the second groove, and a fifth slider is fitted. Pivotally supports the child with the first slider,
A pin is planted on the extension line of the second groove, the pin and the second slider are rotatably supported, and the length is longer than the total length of the sixth slider, the cross member, and the groove plate. A parabolic creation tool characterized by pivotally supporting a third slider with a shaft.