Pin-tumbler-type lock having antipick security action

In a lock of the type having a casing and a core housing that houses a locking mechanism and that is releasably retained within the casing, and wherein the locking mechanism includes a cylindrical locking/unlocking plug defining a keyway and includes a core retaining control sleeve rotatably fitted on the plug and disposed therewith in the core housing, and a row of transversely oriented tumbler bores and associated primary/control tumbler assemblies so constructed and arranged in the core housing, sleeve and plug so that the tumbler assemblies have true primary and control breakpoints which respectively enable a primary key to rotate the plug relative to the control sleeve and core for unlocking the lock, and enable a control key to rotate the plug and control sleeve relative to the core housing for releasing the core housing from the casing, wherein the lock incorporates the improvement of an antipick security action that comprises:

• said sleeve being transversely divided into first and second sleeve segments that are arranged for independent limited angular rotation relative to said core housing, said true primary/control breakpoints in said tumbler assemblies being disposed so that the primary key causes said plug to rotate relative to both said first and said second sleeve segments which are held stationary by said tumbler assemblies at a shear line between said sleeve segments and said core housing, and so that the control key causes said plug to rotate relative to said first segment and causes said second segment to rotate jointly with said plug relative to said core housing to release said core housing from said casing;
• false breakpoint means in at least one of said tumbler assemblies that cooperates with said first sleeve segment for providing one or more false breakpoints along with said true primary breakpoints for causing said plug and said first sleeve segment to rotate conjointly when either said false or true breakpoints are positioned at the shear line between said sleeve segment and core housing during an attempt to pick the lock, such that said plug cannot be rotated sufficiently relative to said core housing to open the lock because said plug is constrained to the limited angular rotation of said first sleeve segment.

In a lock of the type having a housing containing a locking mechanism that includes a cylindrical locking/unlocking plug defining a keyway, and a plurality of transversely oriented tumbler bores and associated key actuated tumbler assemblies so constructed and arranged in the housing and plug so that the tumbler assemblies have true breakpoints which enable a matching key to rotate the plug relative to the housing for unlocking the lock, wherein the lock incorporates the improvement of an antipick security action that comprises:

• a sleeve rotatably fitted on said plug and arranged for independent limited angular rotation relative to said housing, said true breakpoints in said tumbler assemblies being disposed so that the matching key causes said plug to rotate relative to said sleeve and housing;
• false breakpoint means in at least one of said tumbler assemblies for providing one or more false breakpoints along with said true breakpoints;
• at least a first security tumbler bore formed in said core housing so as to intersect with said sleeve, and a security tumbler bore formed in said sleeve so as to extend between said housing and plug, and a security tumbler bore formed in said plug so as to extend from said sleeve inwardly into said plug, said security bores in said plug and sleeve being normally aligned with each other and circumferentially offset from said first security tumbler bore in said housing and being movable into alignment with said first security tumbler bore in said housing when said sleeve and said plug are conjointly rotated relative to said housing due to picking of breakpoints on said tumbler assemblies;
• and
• at least a first security tumbler means mounted in said first security tumbler bore of said housing for causing said sleeve and said plug to be jammed together so as to prevent relative rotation therebetween when said security tumbler bores in said plug and sleeve become aligned with said first security tumbler bore in said housing, said first security tumbler means being constructed and sized relative to said first security tumbler bores in said core housing, sleeve and plug so that when said sleeve and plug become jammed together they are conjointly rotatable relative to said housing but only to the extent of said limited angular rotation of said sleeve which is not sufficient to open the lock.

In a pin-tumbler lock having a housing, plug means mounted for movement in said housing between locking and unlocking positions, keyway means for receiving an operating key, alignable tumbler bores provided in said plug means and housing, and tumbler assemblies arranged in said tumbler bores, the improvement comprising in combination therewith:

• a phantom member arranged adjacent said plug means in said housing, said phantom member being mounted for limited movement in an antipick security mode jointly with said plug means between a first position corresponding to the locking position of said plug means and a second position corresponding to a limited intermediate position of said plug means at which said plug means remains in a locking condition, and said plug means being movable in a key-operated mode relative to said phantom member and said housing between locking and unlocking positions, tumbler bores provided in said phantom member through which said tumbler assemblies are arranged to cooperate with said alignable tumbler bores in said plug means and said housing so that a true operating shear is formed at an interface between said phantom member and said plug means, and a false shear is formed between said phantom member and said housing;
• and
• said tumbler assemblies having true breakpoints that are located so as to be positioned by said key at said true operating shear to thereby permit movement of said plug means from said locking position to said unlocking position, and said tumbler assemblies each having at least one false breakpoint located so as to be susceptible during a picking attempt to being displaced to said false shear to thereby cause said plug means and said phantom member means to be jointly movable relative to said housing so that the limited movement of said phantom member constrains the movement of said plug means and thus prevents said plug means from reaching its unlocking position.