GB672713A - Improvements in and relating to the control of a sequence of operations, particularly of electrical washing machines - Google Patents

Abstract

672,713. Time switches. BRITISH THOMSON-HOUSTON CO., Ltd. June 15, 1949. [June 19, 1948] No. 15956/49. Class 38 (v). [Also in Groups XXIV and XXXV] A control apparatus, e.g. for washing machines, comprises a sequential control for a series of operations, an interval control, means effective during one of the operations for shifting the drive to the interval control, and means effective at the end of the interval for shifting the drive back to the sequential control, a common means being provided for starting the sequential control and setting the interval control. The sequential control comprises a cam drum 14 co-operating with switches 5, similar to those of Specification 636,039, and is driven clockwise by a motor 18 and shaft 17 through gearing 20 ... 25, gear 25 being fixed to the drum 14. The gear 24 is fixed to a spindle 27 pivoted to a gear 26 which is rotatable on the shaft 17 but is normally prevented from counter-clockwise rotation by engagement with a pinion 28. The latter and a gear 29 are rotatable on a spindle 30 and a spring pawl 31 mounted on the gear 29 engages with the pinion 28 so that clockwise movement thereof relative to gear 29 is prevented. Normally, the tip 33<SP>1</SP> of a double-armed lever 33 pivoted at 34 is held in engagement with gear 29 by the engagement of its other end 35 with the edge of gear 25 but when a recess 36 in the gear 25 comes opposite the end 35, e.g. at the beginning of the "wash" period, the lever 33 is moved counter-clockwise by a spring 37 to release gear 29 and lock gear 25. The drum 14 is therefore topped and the gear 26 is now rotated counter-clockwise by the pinion 24 which rolls around the gear 23. After a predetermined and adjustable time an arm 42 carried by gear 26 engages the end 35 of lever 33 which is moved back to its normal position thereby stopping gear 26 and allowing gear 25 to rotate again to resume sequential control. For adjustment of the "wash" period, the arm 42 is preset relative to the end 35 by clockwise rotation of a knob 4, which is fixed to the shaft 17 and, through gears 23, 24, rotates gear 26 clockwise, as permitted by the pawl 31 and latched wheel 29. Counter-clockwise rotation of knob 4 rotates gear 25 and drum 14 clockwise to any required position in the sequence, the pawl 31 and latched wheel 29 preventing the wheel 24 from rolling round the wheel 25. The "wash" period can be set or increased at any point in the sequence, but can only be diminished or eliminated during or at the beginning thereof. Specification 633,054 also is referred to.