GB1196417A - In Combination a Lock Mechanism and a Key - Google Patents

Abstract

1,196,417. Lock mechanisms. VENNER Ltd. 10 July, 1967 [30 Aug., 1966], No. 38703/ 66. Heading E2A. In a combination of a plug and cylinder typs lock mechanism and a key, the lock mechanism comprises a cylinder 12, a plug 15 mounted for rotation in the cylinder and defining a key-hole for reception of the key, a plurality of pivotally mounted displaceable operating members 32 mounted within the plug and each having a convexly curved contact edge 35 facing the key-hole, means 36 normally urging each of the operating members to a locking position, each of the operating members being displaceable to an unlocking position by means of a push on its contact edge from the leading edge of the key, the key being formed with a stepped leading edge 47, the individual steps being arranged to engage the individual contact edges of the opcrating members, the key and key-hole having correspondingly fluted profiles and the individual operating members having their contact edges shaped in dependence on the fluted profile such that the contact edges engage the key substantially along the centre lines Z, Y of the thicknesses of the respective steps thereof. In the construction shown each of the operating members is a lever these being pivoted on a common pivot rod 33 supported in holes 26 in the plus so as to extend normal to the axis 34 of the plug and cylinder; the means 36 which urges each lever to its locking position is a spring 36, one end portion of which is secured around the pivot rod 33 and the other end portion of which is secured to a retainer plate 24, the spring being located in a slot in the lever. The upper edge 37 of each lever is cam shaped and each at its rear is provided with a projection 38; in the edge 37 is a groove 40 the grooves of at least some of the levers being at different distances from the contact edges 35. A talon 41 is pivotally mounted on a rod, 42 parallel to rod 33 and supported in holes 27 in the plug and biassed by a spring 42a to urge the talon away from the keyhole to a fastening position in which its back is located in a cam shaped recess 44 in a locking plate 16; the front of the talon 41 is formed with a projecting arm 45 which engages projections 38 of the levers 32 and has its front surface adjacent the edges 37 of the levers 32 in their looking positions. The lock mechanism; shown has six levers 32 and the key 39 is formed with its leading edge 47 having six steps arranged to engage respective ones of the levers 32. In the locking condition of the mechanism the plug is prevented from rotation in the cylinder by engagement of the talon 41 in the recess 44 and its movement is prevented by its engagement with the edges 37 of the levers; when the correct key is inserted into the keyhole the stepped leading edge 47 of the key contacts the contact edges 35 of the levers 32 and moves them by a push against the action of the springs 36 to the unlocking positions in which all the grooves 40 are aligned and disposed underneath the arm 45 of the talon 41; rotational movement of the plug by means of the key urges the talon 41 forward to its releasing position in which the arm 45 is located in the grooves 40, the interaction of the cam surface of the recess 44 with the back of the talon 41 moving the talon 41; the plug can be moved in either direction to move the talon 41; an incorrect key prevents all the notches being aligned and movement of the talon 41 cannot then take place. The key is formed with a side notch 52 which when the key is rotated receives a flange 14 of the cylinder so that withdrawal of the key is prevented except in the locking condition of the mechanism in a modified construction the talon 41 instead of engaging the recess directly engages it via a ball. In a further modification instead of the plug being free to rotate in the cylinder and being held from rotation by the talon 41 engaging the recess 44, the plug has a projection which engages a recess in the cylinder when the plug is in the locking position, the engagement preventing the rotation; to release the plug for rotation it must be moved axially rearwardly, this movement being prevented when the lock mechanism is in looking condition by the talon 41 which engages a rear wall of the cylinder and the edges 37 of the levers 32. When the key is inserted into the lock mechanism it first moves the levers so that their grooves are aligned and when this has been done a further push on the key causes the plug to move rearwardly the movement also causing the arm 45 to enter the grooves in the levers so that the plug can then be rotated. The plug is urged forward by a compression spring.