Patent GB-531876-A (GB)
Title: Apparatus for surfacing and polishing stones, marbles and other hard materials
IPC: B24B27/00
Filed: 1939-08-05
Abstract: 531,876. Surfacing and polishing stone, marble, &c. MAYER, L. Aug. 5, 1939, No. 22765. Convention date, Aug. 13, 1938. [Class 60] In an apparatus for surfacing and polishing stone, marble or other hard blocks, plates or sheets, of the kind comprising rubbing tools having tangential contact with the work and carried by a rotating frame and also oscillated radially the tools are for each turn of the frame caused to assume different oscillating positions so that the whole surface may be operated upon uniformly. The shaft 8 on which the rubbing tools 55 are mounted may be carried by an arm 2 pivoted at 3 to an arm 1 pivotally mounted at 5 on a support 6 forming part of a frame 4 such as a wall or partition. The shaft 8 is driven by belt and toothed gear from a member connected by a universal joint to the end of the shaft 8 and a number of brackets 15 on which are pivoted on axles 16 the supports 17 for the rubbing tools. The universal joint may consist of a spherical member 11 on which are mounted discs 12, 13 retaining an annular member 14 carrying pins 19 passing through holes 20 in the part 11 so as to communicate rotation of the shaft 8 to the supports 17. The supports are provided with extensions 21 carrying spherical rollers 24, which are mounted on ball or roller bearings and engage a spherically surfaced eccentric 25 carried by a sleeve 27 so as to oscillate the supports 17 radially. The angular position of the eccentric is varied by rotating it from the shaft 8 through spur gear 30, 31 and a two speed forward and reversing gear controlled by a sliding pinion assembly 38, 39. When the assembly 38, 39 is in the neutral position, as shown, alteration of the angular position of the eccentric is effected by contact with the rollers 24. A roller bearing 28 is provided between the eccentric and shaft 8. The rollers 24 are held in contact with the eccentric by springs or weights. In the form shown the extensions 21 of opposite supports 17 are engaged by cross members 49 connected by tie members 50 provided with adjustable springs 51. Spherical members 18 are provided on the axles 16 and notches 54 in the extensions 21 engage the cross members 49 so that the supports 17 may also oscillate laterally to enable the tools 55 to accommodate themselves to the surface of the work in all positions. In order that reciprocal action between the tools and work may be uniform in spite of variations in the radial distance between the arc of contact and the axis of the shaft and thus in the speed of movement of the contact lines, the tools are trapezium-shaped with their smallest base near the shaft 8, so as to vary the length of the contact lines and thus render the amount of work done by the tools the same for all the contact lines. The tools are mounted in holders 56 with conical extensions 57 and projections 58 to prevent rotation of the tools about the extensions 57. Pressure may be provided by the weight of the tool mountings assisted by a spring 160, and by a hand-operated sleeve 60 secured to the shaft 8.