GB694443A - Improvements in electric power transmission for sewing machines and the like - Google Patents

Abstract

694,443. Motor driving arrangements. AMERICAN SAFETY TABLE CO., Inc. Aug. 25, 1950 [June 8, 1950], No. 21124/50. Class 35. [Also in Group XXIV] In a drive unit comprising an electric motor 10 mounted in a cylindrical housing 16 below a table 53 for driving a sewing or other machine, mounted above the table, through a cork-faced clutch disc 27 fast on the shaft of a driving belt-pulley 28, and axially movable therewith, by a spring-loaded treadle-actuated bell-crank 33, between a conically-ribbed clutch face 14 on a motor fly-wheel 12, and a coned brake rib 40, on the fixed housing 16, the axial travel of the clutch disc 27 between clutch and brake positions is adjustable to vary the actuation speed, but axial adjustment of the driving motor 10, in the fixed housing 16. Such adjustment externally of the housing is effected by turning a grooved sleeved nut 48, retained axially in the fixed housing 16 and threaded on a bolt 42 fixed to the motor 10, which latter is clamped in adjusted positions in the housing 16 by pinch bolts 22. To adjust the tension of the driving belt 55 the housing 16 is swung around a pivot 58 on a fixed bracket 56 and retained in adjusted positions by a telescopic link, the two parts 61-62 of which are adjustably secured together by a bolt 63 passing through a slot in one part. To permit removal of the belt 55 without disturbing the tension adjustment, the link 62 is retained on the housing 16 by a pin 66, Fig. 7, fast on the housing and passing through L- shaped slots 65 on the link, the pin being normally locked in the short arm of the slots, as shown, by a spring 68. Pressing the link towards the motor housing frees the pin 66 for movement into the long arm of the slots 65 so that the housing 16 can be pivoted upwards to release belt tension sufficient for belt removal. The belt has a pivoted cover-guard, not described. The motor fly-wheel 12 has vanes to circulate cooling air and at 70 carries two electrical supply sockets, one for the motor, the other for low-voltage lighting.