Correlation Between Parameters and Geometry in Case of Designing Spiral Twist With Variable Pitch

• Main Authors: Ivan CISMARU, Camelia COŞEREANU
• Format: Article
• Language: English
• Published: Editura Universitatii Transilvania din Brasov 2016-12-01
• Series: Pro Ligno
• Subjects: spiral twist; variable pitch; longboard; geometry; parameters; tapering
• Online Access: http://www.proligno.ro/en/articles/2016/4/cismaru.pdf

The aim of the study presented in this paper is to analyze the correlation between the parameters of a spiral twist and the geometry of the tapered and double truncated cone solids on which it is applied, in order to design a helical trajectory with variable pitch, aesthetical harmonized with the shape and sizes of the furniture wood component. The property of the spiral twist with variable pitch (as helical trajectory on a double truncated surface) is that its axial pitch is proportional to the variable diameter of the wood part on which it is processed, so to create the maximum aesthetic effect of the proportion between the volumes and the dynamism required by the ornament function of the piece of furniture. The diameter size of a double truncated wooden part, which vary along its length, depends both on the position from the edge where the correlation is done and on the piece taper size. The proportion between the pitch measured on the part surface and the corresponding diameter has to comply with the proportion between the axial pitch and the corresponding diameter. The axial pitch cannot be measured, but it can be calculated depending on the pitch measured on the part’s surface. Correlation between the geometric parameters of the spiral twist with variable pitch and the geometry of the designed wooden part on which it is processed (Dmax, Dmin, ∝, ϴ) is very important for the aesthetic reason of the ornament and also for defining the kinematics during machining it.