GB294457A - Improvements in and relating to machines for cutting concentric tubes from a tree trunk - Google Patents

Abstract

294,457. Kleinholz, H. March 12, 1928. Drilling-machines; cutters. - A machine for cutting concentric tubes out of a tree trunk comprises a rotary face-plate b to which the trunk c is attached and a slide e carrying a non- rotary sleeve f provided at the forward end with an annular cutter head g. The trunk is first turned externally to the required diameter of the outer tube and is steadied by a support d during its rotation. The cutter head g comprises four cutters i, k, m, n, Fig. 2, of which the first has an end-cutting action and also operates on the interior surface of the tube being cut, the second acts on the exterior of the core o, Fig. 4, the third removes the annular shell of debris, whilst the last takes a finishing cut on both sides. The cutters are secured in dovetailed radial slots in the head g. The sleeve f is guided by a member h and is supported on the slide e by a member q which is provided with an annular recess q<1>, Fig. 4, connected by flexible pipes s to a compressed-air reservoir t. Pipes p leading from the recess q<1> along the exterior of the sleeve supply air to the cutters for cooling and removing debris. Additional external pipes r, Fig. 1, lead from the recess to a point mid-way in the length of the sleeve and direct compressed air rearwardly when the cutters have penetrated a considerable depth into the work. Another pipe s<1> leads to the rear closed end of the sleeve and supplies air to the annular space between the sleeve and the core o to prevent the accumulation of debris therein. Further external pipes v, Figs. 1 and 4, supply air to the annular space and are used alternatively with the pipe s'.