DIGITALNA ARHIVA ŠUMARSKOG LISTA
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| ŠUMARSKI LIST 1-2/1965 str. 40 <-- 40 --> PDF |
oštrenje. Zavisnost ugla oštrenja od prečnika turpije i nadvišenja »h« je jako izražena, što se pri oštrenju bez upotrebe odgovarajućih naprava negativno odražava na kvalitet oštrenja. Ovim razmatranjima obuhvatili smo najvažnije faktore u vezi sa oštrenjem zuba lanaca motornih pila koje se danas upotrebljavaju u eksploataciji šuma. Iz izloženog dovoljno je jasno da je mišljenje o težini oštrenja zuba motornih pila relativno i da se više odnosi na vreme i napor, a mnogo manje na složenost oštrenja i potrebnu preciznost. LITERATURA 1. Anikin , B. P.: Mehanizacija lesorazrabotok, 1940. 2. Popović , V.: Iskorišćavanje šuma, 1954. 3. Beršadskij , A. L.: Rezanie drevesini, Moskva, 1956. THE CUTTER AND THE ELEMENTS OF SHARPENING POWER-SAW CHAINS Summary The author deals with the elements and the significance of the cutter and with the sharpening of power-saw chains used in logging. He points out the superiority of the new tooth form (Fig. 2) over the old tooth form of non-mechanized saws (Fig. 1). In the introduction he explains the role of individual elements of the cutter in the light of the theory of the wood-cutting process. On a tooth edge the author distinguishes three parts: horizontal (Ho), vertical, transition (Po). On explaining the role of the individual parts of the cutter or the edge, he points to the rough notion of the elements of sharpening in practice, and after some critical comments gives the definitions of the sharpening angles for the individtial parts of the cutter. The major part of the paper is engaged with the question of the dependence of the sharpening angle of the individual part on the file diameter and other factorj. The author stresses that sharpening angle of the vertical part of cutter depends on the angle which takes the file axis towards the direction of the chain motion, but ho likewise points to the fact that the sharpening angle of the horizontal part of the cutter does not depend on the file angle mentioned towards the direction of the chain motion. He illustrates this in Figs. 5, 6, and 8, presenting also a matematical expression for these relations. Equation 1 represents the dependence of the sharpen´n^ angle of the horizontal cutter part (minimum angle) on the file diameter and the tile superelevation above the cutter edge. Equation 2 indicates the dependence of the sharpening angle of the horizontal cutter part on the so-called relative file superelevation above the cutter edge only, while the diagrammatic representation of this dependence is given in Fig. 8. According to the author, the sharpening angle of the horizontal part does not depend at all on the angle which the files towards the direction of the chain motion, but only on the file superelevation above the cutter edge. In this connexion the author introduces the concept of the so-called minimal or tangent angle of sharpening from which he distinguishes the over-all angle of sharpening — the concavity of the cutter front-side. When the file superelevation above the cutter edge remains the same in the relative amount (in parts of file diameter), then also the initial sharpening angle remains the same (Fig. 5b). On the basis of an analysis of the elements and role of the indicidual parts of the cutter edge, the author draws the conclusion about the superiority of the new cutter over the teeth of non-mehanized saws, and in doing so he especially points to a smaller cutting angle and the sharpening angle of the horizontal cutter part. Then he stresses the significance of precision sharpening, and the drawbacks when the sharpening operation is performed without adequate devices. He also points to the imperfections of sharpening with cylindrical files. |