Pneumatic sanding roll for flexible abrasive cloth sleeve

#The present invention herein described relates to a sanding roll that is filled with air wherein an abrasive cloth sleeve mounted thereon is locked in place by the expanding rubber socket.

#Sanding and polishing, particularly of wood but also other materials, with sandpaper and abrasive cloth are time consuming work that is made easier by using sanding rolls in different configurations. One commonly occurring problem with many sanding rolls is that they are too hard and cause vibration, they cause grades and remove too much material instead of being soft and flexible so that an even and smooth surface is created while maintaining the desired shape. Air filled rubber sanding rolls having endless bands of abrasive cloth have provided a solution to this problem for a long time. The technical construction of these rolls has not made it possible to make them in small dimensions while maintaining the same or similar level of usefulness.

#One object of the present invention is to provide sanding rolls having small dimensions while keeping or even improving the areas of application compared to conventional air sanding rolls. To solve this problem, a valve construction has been invented that has an air inlet drilled along a center line of the driving axle and which hole terminates in the inside of the sanding roll. The air is let out by loosening a nut that holds the upper spacer in place.

#FIG. 1 is a cross-sectional side view of the pneumatic sanding roll of the present invention;

#FIG. 2 is a cross-sectional side view of an alternative embodiment of the sanding device; and

#FIG. 3 is a top view of the unfolded abrasive cloth used in the sanding device shown in FIG. 2; and

#With reference to FIG. 1, the shaft of the sanding roll device has been marked with 1 on the drawing, and the drive axle is marked with 2 and the captured rubber socket is marked with 3. This is equipped with O-rings 4 and are tightened with a spacer 5 and a nut 6 on the upper part of the sanding roll and at the bottom of the sanding roll by a spacer 7 and a screw 8. The air supply channel is marked with 9. The driving axle may extend into a chamber 10 of the inside of the device 1. A piece of rubber tube 11 functions as a back valve and encloses the middle axle 12 of the shaft and also the end of the air supply channel that is marked with 14. The abrasive cloth is marked with 13.

#With reference to FIGS. 2-4, the sanding roll 20 has a semi-spherical shaped bendable abrasive material 22. A tube-shaped open end 24 of the material 22 has a flexible adhesive tape 26 attached to an inside the material 22 so form the tube shape. Preferably, the tape 26 is bendable but not extendable. The tape 26 may be attached to the inside of the material 22 in any suitable way such as by Velcro. It may even be possible to loosely apply the tape or band 26 outside the material 22 because, as is described below, the band 26 is then pressed hard against the material 22 and the friction between the two surfaces alone may be sufficient to hold the material 22 in place.

#As best shown in FIG. 3, the abrasive material 22 has a star-shaped form, when flattened, that includes a round center 28 and outwardly protruding leg sections 30. Preferably, the material 22 is bendable but not extendable. Each leg section 30 has a tapered inner end 32 that is attached to or integral with the round center 28. The abrasive material 22 forms the semi-spherical shape by attaching the leg portions 30 to the tube-shaped tape 26, as best shown in FIG. 4. There may be elongated gaps 34 formed between each leg portion 30.