Patent GB-486785-A (GB)
Title: Improvement in a rubbing machine
IPC: B24B23/04
Filed: 1936-12-10
Abstract: 486,785. Polishing &c. flat surfaces. DEHN, F. B. (Sterling Products Co.) Dec. 10, 1936, No. 33999. [Class 60] In a rubbing-machine for sanding, polishing, and like operations on flat surfaces and comprising mechanism within a housing for reciprocating an external rubbing shoe, the shoe is mounted on the outside of the housing by yieldable means so as to allow vertical reciprocation but prevent tilting of the shoe with respect to the housing. In the form shown in Fig. 1, the housing 15 has an extension 16 containing a motor 17 which drives a pulley 23 through a belt 22. The shaft 24 of the pulley operates through an eccentric 27, 28 to reciprocate an arm 32 which at its other end embraces the upper end of a tubular member 35. A reciprocating motion is thus transmitted to the member 35 which is attached to a guided slide plate 37 and depends through the housing 15. The lower end of the member 35 projects into a bushing 48 anchored within a sleeve 50 upstanding from a plate or rubbing shoe 47 of rubber or similar material. The member 47 is also connected to the housing by means of flexible annular hangers 67 attached by bolts 66 to the member 47 and to the housing by means of rods 68 passing through the depending side flanges of a bottom plate 42. A layer 59 of said paper, emery cloth or the like is secured to the member 47 by means of strips 61 pressed into grooves 60 by means of hooks 62, 63 and springs 64. A flexible shield 54 is provided around the member 35 between the housing and the rubbing member. The motor may be surrounded by a cooling water jacket from which water is discharged on to the work or alternatively the motor may drive a fan for air cooling. In a modified form, Fig. 5, the motor 17 is omitted and the member 35 is reciprocated by an arm 93 from the stud 90 of an eccentric disc 89 mounted on a shaft adapted to be coupled to a flexible shaft driven by external means. The abrasive layer 59 is retained by a rubber frame 107. A pin 104 passes through slots in the members 35, 48 and 50 and the rods 68 are dispensed with, the hangers 67 being anchored to the plate 42 by depending studs 74 if desired. In another modification, Figs. 10 and 13, adapted to be operated pneumatically the housing includes a cylinder block 189 in which a piston 191 is reciprocated by pressure air admitted alternately to the opposite ends of the cylinder under the control of a slide valve comprising valve heads 213, 218 connected by a rod 215. Passing diametrically through the piston is a drive shaft 194 connected to the rubbing shoe. At the upper end of the shaft 194 is an integral cross-head 232 having a stud 233 on which is mounted an arm 234 which at its other end embraces a pin 237 projecting eccentrically from a flywheel 238 journalled in an upper bearing 240. The pin 237 is integral with a disc 242 from the underside of which projects a pin 241 which is concentric with the flywheel and is journalled in a lower bearing 243. Surrounding an eccentric collar 244 on the pin 241 is a plate 245 slidably engaging within a frame 246 adapted to rock about a pivot at one end and to actuate the slide valve rod 215 through a connecting stud 248 at its other end. The source of air under pressure is connected to an inlet 200 which communicates past a valve 202 operated by a cam disc 206 with chambers 208 and 211 from which the air is supplied to the ends of the cylinder under the control of the slide valve. An inlet 249 controlled by a valve operated by a cam disc allows water to pass to passages such as 253 with openings 254 from which water is distributed on to the work.