Creation of a spiral on the drawing is used for the image of some elements in architecture and the equipment. For example, screw elements on a surface of cones or a spiral of heating elements.
It is required to you
- Sheet of paper, pencil, ruler, compasses, eraser.
Instruction
1. The simplest spiral on the drawing can be received relocation of the centers of a semi-circle from one center of a spiral in another. This detail is simple in construction and has an equal step of increase in radius of rounds. For its construction designate the center of a spiral of O on the sheet of paper or the drawing.
2. Through the center of a spiral draw a horizontal straight line. Its length from each party from the center has to be more or is equal to the maximum radius of a spiral.
3. Note on a straight line a point at distance from center O which to equally minimum radius of a spiral. It will be the second center of a spiral which is necessary for its construction. Designate it as O1.
4. From the center of a spiral of O carry out by compasses an arch which represents a circle half. The arch begins from the center of a circle O1, and comes to an end through 180 degrees, having reached the constructed horizontal straight line. Radius of an arch is equal to the minimum radius of a spiral.
5. Set to compasses the size equal to two minimum radiuses of a spiral, and establish his leg with a sharp tip in the second center of a spiral - O1. Carry out an arch which begins in that point in which the first arch ended, and comes to an end, having reached a horizontal straight line from the opposite side of the center of a spiral O.
6. Similarly execute the third and the subsequent necessary steps of construction filched. Semi-circle radius for the third step has to be equal to the minimum radius of a spiral turn increased by 3. Arch radius for the subsequent steps equals to number of a step of construction which is increased by the minimum radius of a spiral turn.