Wide belt sanding machine with improved support for outboard end of cantilevered center bar

Claim 1

A belt-type sanding machine having a main frame with upright side frame sections, a horizontal work support between said side frame sections and a sanding head above the work support carried by a horizontal center bar having an inboard end securely fixed to one of said side frame sections and an outboard end overlying and spaced above the other side frame section, said sanding head having an orbitally driven endless abrasive belt which, during operation of the machine, has its downwardly facing bottom portion pressed against a workpiece on the work support along an elongated contact zone that extends transversely across the machine, and which abrasive belt must be periodically removed and replaced, and in the act thereof passes through the space between the outboard end of the center bar and the top of the adjacent side frame section, said machine being characterized by improved means for separably connecting the outboard end of said center bar with the side frame section therebeneath, said means comprising: A. a removable spacer block of fixed thickness; B. structure at the underside of the outboard end of the center bar providing a substantially horizontal wall with a downwardly facing surface that is substantially bisected by a vertical plane passing thru said elongated contact zone; C. structure on the side frame section beneath the outboard end of the center bar providing a substantially horizontal wall with an upwardly facing surface opposing said downwardly facing surface and spaced therefrom a distance greater than the thickness of said spacer block, said upwardly facing surface being directly below said downwardly facing surface and hence also substantially bisected by said vertical plane; D. a pad vertically adjustably connected with one of said two substantially horizontal walls and having a surface that in all positions of adjustment of the pad is at an elevation between said opposing surfaces and faces the other of said walls and is also substantially bisected by said vertical plane; E. means for adjusting the elevation of said pad with respect to the wall with which it is connected and for securing said pad in an adjusted position at which its said surface is so spaced from the surface of the wall it faces that insertion and clamping of the spacer block between said facing surfaces accurately locates the sanding head with respect to the work support; and F. clamping means operable to draw said two substantially horizontal walls towards one another and thereby clamp said surfaces between which the spacer block is inserted tightly against the block.