| 摘要 |
Compound angle saw cuts are made with precision on lumber components in the mass production of hip, valley and jack rafters. The required cuts are made by a power-driven circular saw blade which is caused to traverse a linear guideway in one direction with the saw blade in a first angular position to produce a first compound angle cut, followed by reverse traversing of the saw blade along the linear guideway while in a second angular position perpendicular to the first angular position to produce a second compound angle cut. The saw blade, its linear guideway and operating elements are attached to a control arm forming a part of a pantograph linkage which can be driven around a sector gear having a protractor scale to establish the roof slope angle for which rafters are being cut. The sector gear is adjustable on a primary support along a linear path to allow the axis of rotation of the control arm and saw blade to be located in a reference plane defined by the top surface of a lumber component conveyor. The axis of rotation is at all times perpendicular to the linear guideway axis. The linear guideway and saw blade are also adjustable on the control arm when the saw blade is at the mid position of its angular adjustment and in a plane parallel to said axis of rotation for making square cuts through lumber components so that one face of the saw blade can be placed precisely on the axis of rotation. Lumber components are delivered in succession intermittently to a cutting station and are held at such station while the saw blade produces the compound angle cuts. |
