575,203. Door latches. EVERED & CO., Ltd., and WILSON, A. H. March 4, 1944, No. 4071. [Class 44] In a door-latch operating mechanism wherein in the handle at one or each end of the spindle is associated with an auxiliary spring to aid the latch spring in returning the handles to normal position after retracting the bolt, the spring 15 of known flat coil form is mounted in a circular box-like casing 14 housed in a recess 13a in the rose-plate 13 and held against rotation therein by radial lugs 14a engaging corresponding notches in the wall of the recess. The casing is removable for reversal if necessary according to the hand on which the door opens so that the spring is wound up by the rotation of the spindle in retracting the bolt. A circular cover plate 14e for the casing is rotatable on a recessed seating 14f by the spindle 11 which fits a square hole formed axially through a boss 14d extending from the plate 14e across the casing to take a bearing in a circular hole 14c in the bottom of the casing. Rotation may be limited by a radial lug (not shown) on plate 14e working in a segmental recess 14h in the casing wall. The outer end of the spring is hooked and anchored by a hook projection 14i on the casing wall, the carrier end 15a being anchored in a slot in boss 14d. The handle 12 is secured to the spindle by a pin 16, the spindle and attaching arrangement preferably being as described in Specification 465,364. The handle shank 12a bears only against the outer face of the rose plate, to prevent detachment of the plate from the door by pulling the handle. The invention is particularly applicable to lever handles, or handles and rose-plates moulded from plastic material.