Finally, with reference again to FIGS。 1 and 2 of the drawings, it can be seen that four-sided frame element 34 to which sanding head 20 is affixed by means of sanding head support element 36 extending between two opposing sides thereof is provided with vertically adjustable movement by means of lifting mechanisms 72A-72D (72B-72D not shown) provided at each end of frame element 34。 Fifting mechanisms 72A-72D are most suitably jack posts that act in response to motor actuation (not shown) through a sprocket and chain mechanism (not shown) that is controlled, as desired, by a suitable manual or suitable computer control mechanism (not shown)。 Conveyor 60 is suitably mounted on support systems 74A-74D (74C-74D not shown) which are most suitably fixed mounting blocks to hold conveyor 60 stationary。 Support systems 74A-74D for conveyor 60 are supportably mounted on machine base 76。

Finally, applicants contemplate that counterweights C can be provided on idle pulleys 52A and 52B at the bottom end of eccentric shafts 38A and 38B, respectively, as required in order to suitably balance the eccentric shafts。

I。Use of Novel Sanding Machine

A。 Conventional Rotating Belt Sanding Machine

To fully appreciate the advancement of applicants’ novel sanding machine that provides simultaneous superimposed movements comprising rotation of the sanding belt about the tension roller and contact roller and translational orbital movement of the sanding belt, applicants note that traditionally the surface sanding of flat panels is performed with conventional belt sanding machines by feeding a work piece into the sanding area by means of a feed belt entrained around a motorized roller and an idle roller。 A vacuum hold system can be utilized to apply vacuum to the feed table beneath the feed belt to improve adhesion of a work piece to the feed belt。 Normally, the feed belt and support table therebeneath is set at a fixed level from the floor such that the rotating belt sanding head must vertically adjust in order 

to accommodate different thicknesses of work pieces。 However, it is also known to utilize a fixed sanding head with a vertically adjustable feed belt and support table in order to accommodate work pieces of different thicknesses。 The sanding action performed by the sanding head on a work piece is obtained by the sanding belt rotating around a contact roller (typically rubber or steel surface) and a tension roller that serves to maintain a proper tension to the sanding belt between the two rollers。

The conventional sanding head is a contact roller (typically with a rubber or steel surface)。 However, an alternative embodiment of the conventional sanding machine is known that utilizes a pad/platen unit that is formed as a one-piece construction for the entire working width of the unit or that is segmented into various sections with electronic control of the intervention of the various sections of the pad/platen unit。

Convention tension rollers are adapted to be raised or lowered for applying the proper tension to the sanding belt as noted above, and when the tension roller is lowered it will further allow for the substitution or the replacement of the sanding belt as required during use of the sanding machine。 Moreover, it is well known for the tension roller to be provided with a swinging movement (in addition to the vertical movement) to maintain proper tracking of the sanding belt on the sanding head during use of the sanding machine。 Also, although abrasive endless belts are well known in the sanding machine art, it is also known for the sanding head to utilize other sanding media such as rollers formed of steel, nylon or natural fiber brushes which are all well known in the industry for various abrasive/polishing and uses。

B。 Operation of Novel Sanding Machine

Applicants’ novel sanding machine 10 combines a single orbital movement of sanding head 20 with the conventional rotation of sanding belt 32 about tension roller 22 and contact roller 24。 In use, electric motor 50 rotates eccentric shafts 38A and 38B by means of belt 54 driving pulley 52B which in turn motivates belt 56 so as to drive pulley 52A。 The teeth on belts 54 and 56 serve to maintain a constant ratio of rotation of eccentric shafts 38A and 38B by electric motor 50 and pulley 50A connected to the drive shaft thereof。 Eccentric shafts 38A and 38B are arranged in phase so that when the shafts are turning the circular trajectories of each shaft 38A and 38B are in phase and the same radius of eccentricity of shafts 38A and 38B is achieved。 Eccentric shafts 38A and 38B impart the single translational orbital movement to lower roller supports 28A and 28B and upper roller supports 30A and 30B which in turn impart the single translational orbital movement to eccentric shafts 38A and 38B and to tension roller 22 and contact roller 24。