Patent GB-636274-A (GB)
Title: Improvements in or relating to electrically-driven floor polishing machines
IPC: A47L11/40
Filed: 1947-10-14
Abstract: 636,274. Floor - polishing machines. PATCHETT, G. W., and STERLING ENGINEERING CO., Ltd. Oct. 14, 1947, No. 27525. [Class 138 (i)] In an electrically-driven floor-polishing machine of the kind in which polishing brushes are rotatably mounted on a frame carrying the electric motor and the means for effecting driving engagement between the motor and brushes, and a handle is provided for moving the machine over the floor, the drive between the motor and the brushes is effected by frictioned contact between the driving- shaft of the motor and one of the brushcarrying wheels and between said brushcarrying wheel and the other brushcarrying wheel or wheels, the said wheels rotating on bearings arranged to pivot eccentrically to the central axis of said bearings and said wheels, resilient means being provided to pivot said bearings in a direction to effect driving engagement between said driving-shaft and said wheel and between said wheel and said other wheel or wheels. The floorpolishing machine, Fig. 1, comprises a casing 2, housing an electric motor, which casing has a lower portion 3 enclosing the driving mechanism for three wheels 4 (referred to separately as 4a, 4b and 4c) each of which carries a brush 6. The bottom of the casing 3 is closed by a casing 5 having three openings therein through which the brushes 6 protrude. The motor and the wheels 4 are mounted on a plate 7 secured to the casing 3 to which plate are also fitted two brackets 9 pivotally connected to the forks 10 of a sleeve 11 to which is fitted a handle 12. The spindle of the electric motor has a pulley 18, Fig. 5 (underneath view), fitted to its lower end, which pulley drives by frictional contact a tyre 29 of the wheel 4a, which wheel drives also by frictional contact wheels 4b, 4c. Each wheel 4, Fig. 6, is freely rotatable on ball-bearings about a bush 22 integral with a grooved pulley 23, the central axis of which pulley is eccentric to the central axis of the bush 22 and the ball-bearing. Each pulley and bush is rotatably mounted, on a spindle 24 and is retained thereon between a collar 25 and a spring clip 26 fitting in a groove 27, The wheel 4 has a central depending screwed spigot 28 to which is connected the brush 6. A tensioned helical spring 30, Fig. 5, is anchored at its ends in the grooves of the pulleys 23 associated with the wheels 4b, 4c in such a manner that the bushes 22 turn eccentrically on their spindles 24 to cause the wheels 4b, 4c to maintain contact with the wheel 4a. A spring 31 anchored to a screw 58 fixed to the plate 7 and to the pulley 23 associated with the wheel 4a is so arranged that the bush 22 is turned eccentrically on its spindle 24 to cause the wheel 4a to maintain contact with the driving pulley 18. The tension of the spring 30 is not sufficient to cause the wheels 4b, 4c to push the wheel 4a out of engagement with the driving pulley 18 against the tension of the spring 31. Means for disengaging the wheel 4a from the driving pulley 18 are operated by the handle 12 as it is brought into the vertical position. A finger 42 on the fork 10 engages a pivoted bracket 35, Fig. 1, which also causes a spring-controlled arm 36, Fig. 5, to engage with a pin 32 radially screwed into the pulley 23 associated with the wheel 4a and so causes the bush 22 to turn eccentrically on its spindle 24 and disengage the wheel from the driving pulley 18. The handle 12 is locked in the vertical position by a spring plunger device mounted in the sleeve 10, which plunger engages in a recess 54 of a catch spindle 57, Fig. 1, mounted on the top of the casing 2. The plunger is releasable from the recess 54 by a lever operable by a foot-pedal 53 mounted on the fork 10 adjacent to the sleeve 11.