A combination lock comprising a looped shackle movable between a first locked position, a second unlocked holding position and a third fully released position after zero, or some other preselected number on the dial face has been rotated to an index mark on front side of the case, said holding means being a guided pin engaged with a slot in long leg of the shackle releasable into an apeture on under side of the dial;
- locking means movable into and out of engagement with provided notches in legs of the shackle;
- said locking means being composed of solid latching hooks at the top end, with unlocking lugs at the bottom end, having sides provided with lost motion slots therein to accomodate stationary pivot pins secured to parts of the case, fence means including a fence for moving the locking means out of locking engagement with said notches of the shackle;
- a calibrated dial rotatable on a common axis with a plurality of locking tumblers mounted axially on a centrally located shaft perpendicular to face of the dial;
- means for sequentially rotating said tumblers to and fro for aligning the gates of all the tumblers with the fence, for movement of said fence into said gates for moving the locking means out of engagement with said notches of the shackle, said gates being located on the perifery of outer disks of the tumblers, frictionally held to inner hubs of the tumblers to allow provided driving means between the dial and tumbler hubs to new selected positions relative to gates of the dial;
- means for dialing and activating a master tumbler means for stopping all the disks of the said locking tumblers for slipping all of the said hubs to a preselected number on the dial face;
- and means for releasing the said disks preparatory to rotating with the fence for opening of the lock;
- means for pivoting the locking means into deeper engagement with notches in the shackle legs if and as the shackle is vigorously pulled outward of the case while the locking means is engaged with notches of the shackle leg;
- and means for wedging the locking means tighter into notches of the shackle legs if the shackle is forcefully pulled outward against inner surface of the case when the locking means is engaged with the shackle notches as aforesaid;
- means for detecting each circumferentially spaced graduation on the dial face as the dial is rotated and means for effecting a discernable pause at each such graduation, thus diminishing meed for close scrutiny of the dial face in so doing;
- means for blocking the dial from rotation prior to contact of the fence with disk rims of the tumblers thus foiling all attempts by pick-locks for feeling or listening out positions of tumbler disk gates relative to the fence;
- means for providing a guided mounting slide plate with a preloaded safety compression spring operable between an unlatching bar secured to said slide plate and an actuating finger plunger passing through a hole in an upturned end of said slide plate and confined therein by a flange at inside end of the plunger, said spring being only partly compressed, will compress further when internal parts are not properly positioned to function, thus serving to protect internal mechanism of the lock from damage;
- a portion of the upturned slide plate is then turned inward to form a flat pedestal upon which the fence means is mounted;
- compressive spring return means are provided at the opposite end of the slide plate;
- which return spring functions between a spring well cup secured to back case plate aligned with the end of a master combination means actuating rod (secured to the said plunger at top end of the case) which spring then activates a master actuating means near bottom end of the case, said rod being rotatable and axially guided by hole through the locking tumbler shaft mounting post;
- means are provided for bringing a provided compression spring in to alignment with the afore mentioned master actuating knob on an arm;
- and means for lifting the master fence pin and rotating a provided sleeve independantly rotatable on the master fence pin;
- after said means has moved said lift arm a given distance up the said ramp the said sleeve being rotatable by a provided pin secured into the said master fence pin activates a toggle spring for rotating said sleeve clockwise leaving the drive pin and master fence lift arm behind, due to a lost motion rectangular slot in which the said pin operates, through said means a set of locking tumbler disk stopping hooks are resiliently brought to bear against the locking tumbler disks;
- after the said disk stopping hooks have served to slip the disks to a preselected position as aforesaid;
- means are provided for reactivating said toggle spring to throw the toggle spring in the opposite direction for withdrawing the said hooks from engagement with the gates of said disks;
- means for providing enlarged portions of the shackle legs outside of and close to the case when the shackle is in its locked position for the purpose of foiling attemps by pick-locks to gain access to internal parts of the lock through use of any type or thickness of tool or instrument for the purpose of unlatching the hooks, which in conjunction with shape and location of the hook ends and unlocking lugs at lower end of the latching members make such an accomplishment vertually impossible;
- means whereby latching of the shackle holding hooks function independantly one from the other, thus in the event a pick-lock devises means for disengaging one hook from the shackle, the other hook is not effected thereby.