185,219. Miller, C. May 31, 1921. Locks, permutation.-The device consists of a lock in which the combination is formed bv time elements, normally idle and run down, and slotted discs. A knob is turned in a clockwise direction for half a turn to wind up a spring mechanism and free an escapement device operated by this mechanism to rotate the slotted disc. The knob is retained in this position for a predetermined number of seconds, after which period the slot in the disc is in position to receive a finger on the bolt. The knob is then turned counter-clockwise, throwing the first escapement device out of action, and, if desired, winding up a second one. A half-turn in the counter-clockwise direction frees a second escapement device to rotate a second slotted disc for a given number of seconds so that its slot also registers with the bolt finger. A further quarter-turn in the clockwise direction withdraws the bolt by means of a cam on the handle spindle, while a further quarter-turn in this direction allows the first escapement to run down and frees the bolt. A further three-quarter turn counter-clockwise allows the second escapement to run down, the parts being then in their original position. In Fig. 1, one escapement device and one slotted disc are shown. The escapement device has a shaft 13 with a pallet 12 working with the toothed wheel 11 and terminating in a finger 14 which is normally prevented from oscillating by the periphery of a controller-wheel 46 rigidly mounted on the knob spindle 47. The escapement device is adapted to rotate the time wheel 20, fixed to the shaft 15, bv means of the toothed wheels 16 - - 19. The time-wheel 20 has sixty holes 23 round it near its periphery, into one of which fits the yielding catch 24 of the slotted disc 21. This disc therefore revolves with the time-wheel. Each space between the holes 23 corresponds to one second of time. Rotatably mounted on the knob spindle 47 is a toothed disc 34 carrying two spring pawls 43, 44, Fig. 3. This disc is the winding-gear and engages teeth 33 on a drum 32 in which is housed a spring 35, one end of which is secured to the drum and one to the spindle 15 of the time-wheel. The initial position of the mechanism is shown in Fig. 3. When the knob 53 is given half a turn in the clockwise direction, a pin 45 on the controller disc 46 engages the pawl 43 on the winding-wheel 34 and turns this with it. The ratio between the wheel 34 and the drum 32 is such that a half turn of the wheel turns the drum through exactly one revolution, when a pawl 42 engages a shoulder 41 on the drum, Fig. 5, to prevent it from slipping backwards. The exact revolution of the drum through one turn is ensured by the Geneva stop mechanism 38, 39, Fig. 3. Bv the time the spring 35 is wound up, the notch 48 in the controller disc has arrived under the finger 14, freeing this to oscillate. This position is shown in Fig. 6, and the mechanism is retained in this position for a predetermined number of seconds. During this time, the escapement device rotates the time-wheel 20, and with it the slotted disc 21. At the end of this time, the slot 28 in the disc 21 is in position to receive the finger 29 on the bolt 30, and the escapement mechanism is then thrown out of action by turning the knob counter-clockwise, the finger 14 being then made to rest inactive on the periphery of the controller disc. If the knob is turned in this direction through three-quarters of a turn, Fig. 7, a cam 49 on the knob spindle lifts the cross-piece 52 of the bolt-struts 51, causing the finger 29 to enter the slot 28 in the disc 21 and withdrawing the bolt 30. This turning also disengages the pin 45 from the pawl 43. When it is desired to close and re-lock the door or the like, the knob is turned further in a counter-clockwise direction through a quarter of a turn to the position shown in Fig. 8. The finger 14 is again freed and the escapement mechanism is allowed to run down, a finger 45<a> travelling round to lift the pawl 44. When the escapement has run down, the knob is given a further half-turn in the counter-clockwise direction, the notch 48 in the controller disc being brought back to the position shown in Fig. 3, the pin 45 snapping behind the pawl 44, and the bolt shooting into its operative position by means of the springs 51<a>, 51<b>, the lock parts being in their initial position. The. running-down of the escapement mechanism revolves the timewheel and the slotted disc to remove the slot 28 from its registering position with the bolt-finger 29. The predetermined interval of time during which the escapement is allowed to run to bring the slot 28 into its correct position may be changed by altering the position of the disc 21 with relation to the time-wheel 20, by means of a key having projections taking into holes 25. The number of seconds is determined by bringing the pin 21a on the disc 21 into contact with the pawl 21b on the casing and turning back the disc 21, counting the holes 23 passed over by the yielding catch 24. The time of one revolution of the wheel 20 is one minute and the time taken to revolve through the distance between the holes 23 is one second. The knob 53 may have depressions passing over a yielding catch 54 in order to assist the operator to turn it through the correct amounts in the dark. If it is not desired to time the interval during which the escapement is allowed to run by a watch, the shaft 15 may be prolonged through the casing to carry a finger moving over a graduated dial. If desired, the operation of the lock may be made more complicated by introducing two escapement mechanisms, each with a slotted disc and controller-disc. Fig. 10 shows the arrangement. Turning the knob 53 half a turn clockwise winds up the spring- motor 32 and frees the escapement finger 14, which is allowed to rotate the disc 21 until its slot registers with the bolt finger 29a. The knob is then given half a turn counter-clockwise, stopping the rotation of the disc 21 and winding up the spring motor 32<1>, freeing the escapement finger 14', and rotating the disc 21<1> for a given time till the slot 28' also registers with the finger 29<a>. A further counter-clockwise quarter-turn withdraws the bolt and throws the second escapement out of action. To relock the door, the knob is given a still further quarter-turn counter-clockwise, allowing the bolt to' shoot, withdrawing the finger 29<a>, and allowing the first escapement mechanism to run down and turn the disc 21 to a locking position. A further half-turn counterclockwise allows the second escapement mechanism to run down and brings the mechanism to its starting position. In this last half-turn the gap in the controller-disc 46 of the first mechanism must be turned quickly past the finger 14 in order that the finger shall not oscillate. The position of the slotted discs 21, 21' on the respective time-wheels 20, 20' are changed to vary the time interval at will, by cogs 61, 61<1> gearing with teeth 60, 60<1> in the slotted discs, and operated by turning parallel shafts 62, 62' by a square key inserted in the hole 64.