Thus, sanding belt 32 is subject to two distinct contemporaneous superimposed movements consisting of the rotation movement about rollers 22 and 24 as well as the single translational orbital movement imparted thereto by rotation of eccentric shafts 38A and 38B by electric motor 50。 Contemporaneously, electric motor 68 is motivating conveyor belt 62 about driven roller 64 and idle roller 66 and electric motor 44 is imparting rotational movement to sanding belt 32 by imparting rotation to contact roller 24 through belt 46 to pulley 48 connected to the shaft of contact roller 24。 In order to accommodate tensioning of sanding belt 32 by vertical adjustment of tension roller 22, eccentric shafts 38A and 38B are splined on the top end (see FIG。 2) to facilitate vertical movement of tension roller 22。 To motivate tension roller 22 upwardly and downwardly, two pneumatic actuators 40A and 40B are provided in sanding head support element 36 positioned between tension roller 22 and contact roller 24 and fixedly secured to frame element 34。 As noted hereinbefore, automatic centering of sanding belt is accomplished by turning shaft pin 22A with pneumatic actuators 42A and 42B mounted on fixed support 30B for tension roller 22。

Thus, applicants’ combination of rotational movement of sanding belt 32 and the simultaneous single translational orbital movement thereof provides an unusually homogeneous sanding pattern on the surface of work piece WP that can render almost unnoticeable the scratches created by sanding belt 32 during working of work piece WP。 Although applicants have described the present invention with particular reference to sanding of solid wood or veneered work pieces WP, applicants’ inventive sanding machine is intended for other applications including lacquered surfaces, plastic materials, marble, ceramic tiles, stainless steel and copper sheet materials and other type of flat surface work piece materials。论文网

II。 Alternative Embodiment of Sanding Machine

Referring now to FIG。 3 of the drawings, an alternative embodiment of the novel rotating belt sanding machine is shown and generally designated 80。 Sanding machine 80 is shown with like numerals for like parts that are shown in the first embodiment of the sanding machine depicted in FIGS。 1 and 2 of the drawings。 Sanding machine 80 is substantially identical to sanding machine 10 shown in FIGS。 1 and 2 of the drawings except for the substitution of an arcuate plate P for upper roller 22 of sanding machine 10。 Arcuate plate P is mounted for vertical movement relative to cross support S which is supported at opposing ends thereof by tension roller supports 30A and 30B。 The use of arcuate plate P provides an alternative system for tensioning endless sanding belt 32 which is entrained around the stationary arcuate plate P and lower contact roller 24。 Similarly to sanding machine 10, sanding machine 80 has two actuators 81A, 81B which are each mounted to cross support S at their lower end and arcuate plate P at their upper end so as to urge arcuate plate P upwardly or downwardly as required in order to properly tension endless sanding belt 32 entrained around arcuate plate P and contact roller 24。 Two pneumatic actuators 84A, 84B are mounted on tension roller support S of arcuate plate P to automatically center sanding belt 32 by oscillating the complete arcuate plate P supported in its center, the fulcrum of oscillation。 The sanding belt 32 provides the signal of inversion of oscillation through a photocell (not shown) in a conventional manner that is well known to one skilled in the art。 (The centering system can be considered similar in principle to the two pneumatic actuators 42A, 42B mounted on support 30B of tension roller 22 in the first embodiment of the invention shown in FIGS。 1 and 2 of the drawings)。

Other than the use of the modified tensioning system for sanding belt 32 as described hereinabove in lieu of tensioning roller 22 shown in the first embodiment of the invention depicted in FIGS。 1 and 2 of the drawings, the remaining functions and structural elements of sanding machine 100 are similar to the first embodiment of the invention generally designated 10 in FIGS。 1 and 2 of the drawings。