Abstract: A guard barrier in front of the exposed portion of the blade of a band saw is raised or lowered responsive to the elevation of the portion of the non-planar workpiece which is approaching the blade to be cut so that the varying length of exposed blade is continuously guarded without interfering with the cutting operation. A pneumatic cylinder controls the position of the guard barrier. Cam followers at the bottom end of the barrier ride along the uneven surface of the workpiece acting as a cam and follower movements operate a throttle valve which controls the pressure in the pneumatic cylinder to cause the barrier to move to and hover at its guarding location. An auxiliary valve is provided for rapid raising of the barrier to accommodate a steep rise on the workpiece, to broaden the range of useful operation in relation to workpiece profiles, and for manually controlled lifting of the guard.An electric system is coordinated with the pneumatic system to provide control and safety features.
Abstract: A band saw which has a displaceable guard rail that covers the saw blade in the cutting region thereof above the feed table and is adapted to be displaced upward in a direction parallel to the saw blade and away from the feed table to the height necessary to allow passage of the stock that is being cut. The band saw includes apparatus for raising the guard rail the necessary height in response to exerting pressure by the stock against the guard rail in the direction of cutting, and the apparatus will then maintain the guard rail at a height conforming to the contour of the stock as the latter is passed through the saw blade. Other apparatus provides smooth movement of the guard rail during cutting operations and provides for securing of the guard rail when the band saw is not in operation.