CIRCULAR SAW Russian patent published in 1997 - IPC

FIELD: longitudinal and cross sawing of wood, wood particle plates, etc. SUBSTANCE: circular saw is made in the form of flat disk 1 with inner hole d and toothed rim 2 along its periphery. The face surface of teeth 3 features hardened structure resulted from the laser shaping of the saw contour. The inner surface of teeth 3 at the bends resulting from the saw setting is additionally hardened by strengthening strips 4 applied by laser treatment of side surfaces 5 of saw disk 1. The saw is manufactured as follows. First a preliminarily cut blank is mounted and fixed on the table of a laser treatment installation. Central hole with a diameter d is cut by moving the table by a special program. Then strengthening strips 4 are applied to the blank to improve rigidity of the teeth surface and to add them wearing resistance. To this end hardening strips 4 are applied at the points of teeth location on both sides 5 of disk 1. The hardening strips are essentially hardening structures of the martensite class applied in compliance with special program by laser irradiation in radial direction. The width of the hardened strip is equal to the width of tooth 3 at its base and the depth of the hardened layer shall not exceed the boundary position of neutral surface between the compressed and tensioned layers of metal during setting the saw teeth 3. The length of the hardened layer is equal to the radius between the tooth point and forging radius and this makes it possible to improve resistance of the circular saw against action of disturbing side forces arising in the course of sawing. After the hardening strips 4 are applied, laser irradiation is used to form the contour of the circular saw, its toothed rim 2. After that the saw is subjected to setting of teeth 3. The setting is fulfilled so that the hardened surface becomes inner surface of tooth and works in compression while the outer surface of the tooth should work in tension. This operation is aimed to exclude cracking of the outer surface of tooth 3 and by this way to increase wear resistance of the saw. The saw manufacturing process is ended by forging saw disk 1. EFFECT: wear resistance of the saw is increased 1-2 to 1-3 times in comparison with saws manufactured by the routine method. 3 cl, 3 dwg