1,175,730. Combination locks. SARGENT & GREENLEAF Inc. 13 June, 1967, No. 27118/67. Heading E2A. A combination lock includes a casing 21, a plurality of selectively adjustable tumbler wheels 29, 30, 31 each having a peripheral recess (not shown) forming a gate, and a rotatable driving cam 28 for adjusting said tumbler wheels located in the casing, a drive spindle 26 fixed to the said driving cam and extending through the casing, the spindle having a dial 25 fixed to one end portion thereof, the end portion outside the casing, a dial ring 24 having a central opening through which said drive spindle projects, a bolt 35, a fence lever 36 pivotally connected to said bolt having a nose 43 for selectively engaging the periphery of said driving cam and a laterally extending fence 39 transversely overlying the peripheries of said tumbler wheels, said driving cam having a peripheral gate 32 for receiving said fence lever nose 43 to permit said fence 39 to enter the tumbler recesses when the latter are adjusted in registry therewith, an annular guard ring 45 of greater diameter than said driving cam pivotally mounted on the latter at a location eccentric to the axis of rotation of the driving cam for arcuate movement from a normal shielding position concentric with the driving cam preventing entry of the fence lever nose into the driving cam gate, to a non-shielding position displaced angularly from said concentric relation, exposing the driving cam gate to receive the fence lever nose, a rotatable actuating member 54 adjacent said guard ring, an actuating spindle extending coaxially through said drive spindle having one end portion fixed to said actuating member and a knob 57 fixed on the other end portion of said actuating spindle centrally of said dial for rotating the actuating member relative to the driving cam over a preselected range of movement, and spring means 51 coupled to said guard ring and actuating member to store up energy during movement of said actuating member toward a selected intermediate position in said range of movement and be shifted to a direction upon passage of said intermediate position to expend the stored up energy on said guard ring to drive the latter fully to non-shielding position. In the construction shown the tumbler wheels are supported to rotate freely upon a hollow boss 22 projecting within the lock casing 21, each of the tumbler wheels being of the kind designed to be changed by means of a combination resetting key to vary the combination of the lock and each comprising an inner hub on which is supported a pair of annular discs, the peripheral gate being formed in the annular discs. Flys 33 consisting of annular rings each having an outwardly radiating projection therefrom are provided between the tumblers 31 and 30 and between the tumblers 30 and 29 to rotate in annular recesses provided in the adjacent faces of the inner hubs of the tumbler wheels 31 and 30; the innermost tumbler wheel 29 is provided with a fly 34 having an annular ring to surround and ride freely on the hollow boss 22 and an outwardly radiating projection terminating in a triangular tip having inclined converging faces. The lock is manipulated to position the tumbler wheel gates in registry with each other and in alignment with the fence 39 by rotating the dial 25 by means of its knob 25a; three complete revolutions and a bit in a counterclockwise direction to bring a preselected dial marking in alignment with the index mark on the dial ring 24, then two complete revolutions and a bit in a clockwise direction to bring another dial marking into alignment with the fixed index mark and then another complete revolution and a bit in a counterclockwise direction to align the third dial marking with the index mark; during this manipulation of the dial the guard ring 45 is in the position illustrated in Fig. 2 where its uninterrupted periphery 46 supports the fence lever nose 43 out of contact with the driving cam 28; the guard ring carries a drive pin 49 which under this condition engages the projection of the fly 34 to impart lost motion drive to the rearmost tumbler wheel 29, the intermediate and forward flys 33 being picked up by pins projecting from the rear and intermediate tumblers 29 and 30 upon subsequent complete revolutions of the driving cam 28. When the tumbler wheel gates have been thus aligned with the fence 39, the dial 25 is rotated in a clockwise direction to bring the zero mark into alignment with a fixed index mark on the dial ring 24. In this position a rearwardly projecting portion of the drive pin 49 is aligned radially with a transition groove 67 in a rear cover 65 of the casing, a limit pin 59 in the dial 25 is aligned with one end portion of a slot 62 in dial ring 24 and the driving cam gate 42 is.disposed immediately below the fence lever nose 43. The knob 57 is then rotated through a selected range rotating the inner spindle and actuating member 54 to shift the guard ring 45 about its pivot pin 48 in an arcuate path to the position illustrated in Fig. 3. When an anchor pin 53 on the actuating member 54 to which the spring means 51 is connected passes clockwise as shown between the end portion of spring means 51 in a hole 52 of guard ring 45, the angular position of the spring which has been highly tensioned during the approaching movement of the end portions thereof is shifted so as to exert a counterclockwise rotating force on the guard ring about its pin 48, the stored energy of the spring means 51 being sufficient to fully move the guard ring 45 to the notch shielding position shown in Fig. 3; provided the tumbler wheel gates have been aligned, the fence lever will then fall under the force of its spring 38 to seat the fence lever nose 43 in the driving cam gate 42 and the fence in the tumbler wheel gates; During such rotation of the knob 57 to shift the guard ring 45, a forward end portion of the limit pin 59 is engaged progressively by a ramp portion and then a flat portion of a cam surface of the knob 57 to drive the limit pin 59 axially rearwardly against the force of its spring 61 into the slot 62 in dial ring 24 adjacent one end of the slot. The dial 25 can then be rotated counterclockwise as shown in Fig. 3 through the range permitted by the slot 62 which is sufficient to effect retraction of the bolt 35 through the action of the driving cam gate 42 on the fence lever nose 43. An arcuate groove in the rear cover 65 which receives the rearwardly projecting portion of the drive pin 49 in the non-shielding position of the guard ring 45 is of similar arcuate range to the slot 62 to also limit rotation of the driving cam in this condition of the lock to this range. To place the lock in locking condition it is necessary to rotate the dial in the reverse direction to bring the drive pin 49 on the guard ring 45 into alignment with a transition groove (not shown )in the rear cover and then rotate the auxiliary knob 57 in the reverse direction which rotates the actuating member 54 and returns the guard ring 45 to its normal position concentric with the driving cam 28.