Patent GB-1309884-A (GB)
Title: Portable sander
IPC: B24B23/04
Filed: 1971-05-03
Abstract: 1309884 Valves; vibrators NITTO KOHKI CO Ltd 3 May 1971 [14 May 1970 29 Jan 1971] 12661/71 Headings F2V and F2X [Also in Division B3] A portable sander comprises a motor 1 having at least one circulating member 19, Fig. 2, movable around a circulator 16 at high speed by compressed air supplied to an inlet 91, the centrifugal force of the member producing vibration of a sanding table 4 carrying abrasive material secured to the underside of the motor, and a handle 8 connected to the upper side of the motor by at least one resident support 5. The circulator may be oval or circular and have a pair of bearing faces 16a on which run the circulating member in the form of a spherical body 19, a number of bodies joined together by a holder (101, Fig. 10, not shown), a section of a toroid or cylinder, upon compressed air from the inlet 91 passing through a pipe 97 and passage 96 into the motor. The circulator is clamped by a bolt 18 between a lower member 11, which is secured to a plate carrying a resilient sanding table 4, and an upper member 15, sandpaper or cloth being secured to the lower surface of the table by spring loaded clips 3a, 3b. The upper member 15 is connected by the resilient supports 5 to the skirt 81 of the handle 8 containing a valve 65 controlling the supply of compressed air to the motor. The table 4 may be replaced by others having parts permitting the abrading of curved surfaces, grooves or projections. In another embodiment, the circulating member 27, Fig. 18, is annular shape and the compressed air is supplied to the periphery of the circulator. In a similar embodiment having an annular circulating member, the compressed air is supplied to a hollow centre 113, Fig. 20, having a sliding vane 116 formed with a groove 117 through which the air passes to a pressure chamber M to cause rotation of the member 118, the latter acting to open and close a port (122, Fig. 21, not shown) for exhausting air from an exhaust chamber N as that chamber diminishes in volume. In a modification of the last embodiment, the circulating member is in the form of an inner annular member 217, Fig. 25, disposed within an outer annular member 218 which rotate in the circulator 214, the compressed air being supplied to a hollow centre 213 having a sliding vane 216. In another embodiment, the circulating member 312, Fig. 31, is circular with teeth 313 on its circumference engaging internal teeth on the wall of the circulator. The member is guided by a projection 316 on its upper face engaging a groove 311 and has a number of openings 317 so that its centre of gravity is eccentric and the vibration has an oval motion. The handle 8 is shaped so as to be easily gripped and houses the valve 65 which is operable by a control knob 66. The valve has a flange 62 and ring 63 which, when seated, closes the passage between an inlet chamber 91 and a passage 94 leading to the motor 1. The valve is movable to its open position by pressure on the control knob moving a control rod 67 slidable in openings in projections 87, 83 of a skirt portion 84 carried by the resilient supports 5 from the motor 1, a resilient ring 72 engaging a groove in the rod moving from engagement with a groove 69 in a cylinder 68 to a groove 70 to hold the valve open without the necessity of manual pressure. To close the valve and stop the supply of air to the motor, the control knob is pressed again and the movement of the rod 67 causes the resilient ring to be compressed within a sleeve 71 slidable within the sleeve. On release of pressure on the control knob, the air pressure in the inlet 91 acts to seal the valve and move the rod, the sleeve sliding with the rod to close the groove 70 so that the rod moves to its initial position with the ring 72 engaging the groove 69. Reference has been directed by the Comptroller to Specification 1246427.