| 摘要 |
<p>Frame saw for sawing of essentially horizontally fed timber by the type of saw working withs saw blades placed largely perpendicular to the direction of feed of the timber, i.e. without overhang, in which frame saw a sash in which the said saw blades are clamped is arranged to be imparted, by means of a crankshaft a reciprocating upward and downward motion with upper and lower turning points in relation to an controlled by a system of guides which by the said crankshaft via one or several guide connecting rods and via one or several controlled guide links is arranged to be moved before the sash phase-displaced in the direction of feed of the timber. The guide system and the guide connecting rods being designed with fulcrums in or in relation to the said guide links , which are pivotably disposed. The fulcrums of the guide system are so located in relation to the fulcrums of the guide connecting rod that the fulcrums of the guide system move along a circular arc with a shorter radius than do the fulcrums of the guideconnecting rod. Said arrangement is made in order to impart to the guide system and thus to the sash with the saw blades a movement with such a horizontal component as to cause the guide system to be displaced against the feed direction of the timber when the sash and thus the saw blades are in the vicinity of the said upper turning point and during the downward movement, and in such a complementary horizontal movement in the feed direction of the timber when the sash and thus the saw blades are in the vicinity of the said lower turning point and on their way up that the sash and thus the saw blades over and above the horizontal motion during the downward and upward movement are alsoimparted during the cutting period of the saw blades such a horizontal complementary motion that the cutting engagement of the saw blades with the timber becomes more or less constant during the greater part of the cutting period.</p> |
