996,052. Locking mechanisms. WILMOT-BREEDEN Ltd. Sept. 18, 1961 [Sept. 24, 1960; Jan. 26, 1961], Nos. 32906/60 and 3074/61. Heading E2A. A locking mechanism comprises a key operated device 1 or 30 rotatable in opposite locking and unlocking directions from a central position, a driven member 2 or 34 rotatable between locking and unlocking positions by the locking device, there being provision for lost angular motion between the device and the member so that the former may return to its central position after having rotated the latter to either of its locking or unlocking positions, stop means 14 or 39, 40 having first and second states in which normal rotation of the locking device in its locking and unlocking directions respectively is prevented and holding means 6 or 35, 36 arranged to hold the stop means in the first state when the driven member is in its locking position and hold the stop means in the second state when the driven member is in its unlocking position. In a first form, Figs. 2 and 3 the key operated device is a barrel lock 1 which is rotatably mounted within a push button 2 inset in a vehicle door handle 3. The driven member 4 is constituted by the push button stem and interengagement between the device 1 and the member 4 is provided by the holding means 6, which is an arcuate abutment on the push button stem 4, and a tongue 5 on the device 1. The dimensions of the holding means 6 are such as to provide the angular lost motion between it and the tongue 5. The stop means 14 is a U-shaped spring the arrangement being such that when the push button stem is in its locking position shown in Fig. 3 the holding means 6 forces one end 16 of the spring 14 away from the centre of the push button 4 so that the other end 17 of the spring 14 moves inwardly into the path of a face 7 of the tongue 5 thus preventing the latter and the locking device 1 from being moved in the locking direction. When the locking device 1 is moved in its unlocking direction it rotates the push button stem 4 to its unlocking position and the holding device 6 rotates and pushes the end 17 of the spring 14 away from the centre of the push button 4 so that the end 16 comes opposite the radial face 8 of the tongue 5 and prevents rotation of the tongue 5 in the unlocking direction. The push button stem 4 is associated with the end of a lever 18 of a door fastening device and in the locked position of the push button stem 4 the lever 18 is aligned with a slot 19 in the stem 4; hence depression of the push button does not move the actuating lever 18. Movement of the stem 4 to the unlocking position brings a step 20 into alignment with the lever 18 so that depression of the push button engages the lever 18 to move the lever. A spring 22 returns the push button to its normal position. An internal locking lever (not shown) movable from inside the door has its free end engaged in a slot 24 at the inner end of the push button stem 4 so that when the locking lever is pivoted it turns the stem between its locking and unlocking positions. In a second form shown in Figs. 6 and 7 the device 30 is rotatably mounted in a housing 31 arranged-to be received in an aperture in the outer panel of a vehicle door. The inner end of the housing is shaped to provide two part-annular tongues 32 and 33 the tongue 32 having a considerably greater circumferential length than the tongue 33. The driven member 34 is a cup which is rotatably mounted on the tongues 32 and 33 and which has a lost motion connection with the member 30; this consists of an hour glass shaped slot in the member 34 engaged by a tongue 37 on the member 30. The device 30 is provided with a transverse bore 38 in the ends of which are mounted two balls 39 and 40 constituting the stop means. A compression spring 42 forces the bores 39 and 40 outwardly against the internal surface of the cup 34 which is provided with two recesses 35, 36 which form the holding means. The recesses 35 and 36 are arranged so that with the device 30 in its central position and the cup 34 in its locking position the recess 35 is opposite one end of the bore 38. In this position the ball 39 is forced into the recess 35 and its centre is then substantially in alignment with the centre of the end 47 of the tongue 23 so that the ball 39 is unable to ride over the end of the tongue. The other ball 40 is held further into the bore 38 and can ride over the other end 48 of the tongue 32 so that the device 30 can be turned in the unlocking direction. When the cup 34 is in the unlocking position the ball 40 is in the recess 36 and the locking device 30 can then be turned only in the locking direction. A radial peg (not shown) on the cup 34 actuates locking means of an associated door fastening device.