GB578027A - Improvements in or relating to rubbing, sanding, or polishing machine - Google Patents

Abstract

578,027. Sanding &c. machines. STERLING TOOL PRODUCTS CO. May 1, 1944, No. 8154. Convention date, Oct. 4, 1943. [Class 60] A rubbing, sanding or polishing machine, in which the sanding &c. pad has an orbital movement, has a counterpoise mounted adjacent the pad and given also an orbital movement whereby vibration is reduced. The machine comprises a housing frame A, Fig. 3, with a handle A<1> and a cap A<2>, a hinged grill A<3> for holding a filter panel A4 in position, an electric motor B with switch B<1>, a counterpoise C and a driving-head D carrying the sanding &c. pad E. The housing A carries the motor B, through which air is blown to slots in the cap A<2> by a fan 23, the ingoing air being filtered by the panel A<4> comprising a thin porous fibrous sheet 26 between metal screens 27, the panel being held in an opening in the frame by the grill door A<3>, hinged at 24 and held closed by a spring 25. Wiring 21 leads to the motor B through a switch B<1> on the handle A<1> and the motor shaft has at its lower end a gear 33, which drives a gear 34 driving an idler gear 35 ; the gear 35 drives gears 36-38, Fig. 9, the gears 37, 38 being splined to crankshafts 39, 40 which impart orbited movements to the drive head D, and similarly the gears 34, 36 impart orbital movement, 180 degrees out of phase with the movement of the head D, to the counterpoise C. The crankshafts are journalled by antifriction bearings in a top bearing plate 43 and in a centre bearing plate 45 secured to the housing A by screw 46, and the plate 43 carries an oil reservoir 47. The counterpoise C makes contact with the plate 45 and with the drive head D through thrust ball bearings, and the head D is supported by stirrup portions 51 depending from the plate 45 and having ball bearing sockets 51a to support cross-bars 52 secured to the head D by screws 53 ; a rubber sleeve 54 is cemented to the margin of the plate 45 and head D and extends at 54a into contact with the housing wall, thereby excluding dust from the driving mechanism. The sanding &c. pad E is carried by the head D so as to allow of slight flexing to suit a curved surface ; for this purpose the head D has therein inserts provided with nibs 56 and part-spherical recesses, and the pad E has a thin steel backing plate 58 having dome shaped detents 59 to engage the recesses in the inserts, and carrying a slidable member 61, Fig. 16, provided with flexible fingers 57 to engage under the nibs 56. The plate 58 has cemented thereto a felt pad 65 and over this is placed a sheet of fabric, sandpaper &c., which is gripped at its bent over ends and tensioned by rotatable tumblers 68 acted upon by spring keepers 66 ; one such tensioning &c. device only may be used, a clamp being used at the opposite end of the pad.