A lock apparatus comprising:
- a lock body formed with a lock core chamber, a lock core opening for access to said lock core chamber, and a shackle insert hole, said lock core chamber having a section formed as a catch chamber which is adjacent to and which is communicated with said shackle insert hole;
- a lock core device received in said lock core chamber via said lock core opening, said lock core device including a cylindrical and axially rotatable lock core which is provided with a latch member that is disposed in said catch chamber, said latch member having an end face which is transverse to an axis of said lock core and which is formed with a pin hole that is eccentric to the axis of said lock core;
- a key which is insertible into said lock core device via said lock core opening and which is operable for rotating said lock core and said latch member between locking and unlocking positions;
- a shackle member having a leg portion which is formed with a shackle groove and which is inserted into said shackle insert hole in said lock body;
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- a catch member disposed in said catch chamber of said lock body, said catch member having a shackle engaging end portion for engaging said shackle groove in said leg portion of said shackle member, and a latch engaging end portion opposite to said shackle engaging end portion and formed with a pin which extends rotatably into said pin hole in said latch member for engaging said latch member such that said catch member is movable between locking and unlocking positions when said latch member moves between the locking and unlocking positions, said shackle engaging end portion of said catch member extending into said shackle insert hole for engaging said shackle groove in said leg portion of said shackle member when said catch member is disposed in the locking position, said shackle engaging end portion being retracted into said catch chamber for disengaging from said leg portion of said shackle member to permit removal of said shackle member from said shackle insert hole when said catch member is disposed in the unlocking position;
- said key having a shank portion with a cross-section formed as a circular sector, and a handle portion connected to said shank portion, said shank portion having first and second radial surfaces that extend along a length of said shank portion, and a curved surface that interconnects said first and second radial surfaces, said first radial surface being planar, said second radial surface being formed with a plurality of key bit portions that are arranged along the length of said shank portion, said key bit portions having radial key bit surfaces that form different angles with said first radial surface to set a code of said key, said shank portion of said key further having a distal end formed as an actuating tip portion;
- said lock core device further including a lock casing mounted in said lock core chamber of said lock body, said lock casing having an inner surface which confines a cylindrical chamber and which is formed with an axially extending locking groove;
- said lock core including:
- a cylindrical inner shell received rotatably in said cylindrical chamber of said lock casing, said inner shell having a rear end mounted with said latch member, and a front end, said inner shell being formed with an axially extending locking slot which is registered with said locking groove when said lock core is in the locking position;
- a stack of annular locking plates received in said inner shell, each of said locking plates having an inner periphery that confines a central hole, said central holes of said locking plates cooperatively defining a keyhole that permits insertion of said shank portion of said key thereinto, each of said locking plates further having an outer periphery that is formed with an engaging notch, said engaging notches of said locking plates being misaligned with one another in accordance with the code of said key when said lock core is in the locking position, said engaging notches being aligned with one another when said lock core is in the unlocking position, said inner periphery of each of said locking plates being formed with a radial inward key engaging protrusion which abuts against said key bit surface of a corresponding one of said key bit portions on said key when said key is inserted into said keyhole and is rotated, said locking plates being rotated by different angles according to the code of said key to align said engaging notches when said key is inserted into said keyhole and is rotated for moving said lock core to the unlocking position;
- a locking rod received in said locking slot of said inner shell, misalignment of said engaging notches on said locking plates enabling said outer peripheries of said locking plates to force said locking rod to extend into said locking groove in said lock casing in order to hinder rotation of said inner shell relative to said lock casing when said lock core is in the locking position, alignment of said engaging notches on said locking plates enabling said locking rod to disengage said locking groove and to extend into said engaging notches in order to permit rotation of said inner shell relative to said lock casing during unlocking movement of said lock core;
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- an annular drive plate disposed in said inner shell at said rear end of said inner shell and disposed between said locking plates and said latch member, said drive plate having an inner periphery which confines a key engaging hole and which is formed with a key actuatable projection that projects radially and inwardly, said actuating tip portion of said key being extendible into said key engaging hole for engaging said key actuatable projection so as to enable co-rotation of said drive plate with said key, said drive plate being formed with a drive projection, said latch member having an actuatable section which is driven by said drive projection such that rotation of said drive plate can result in corresponding rotation of said latch member between the locking and unlocking positions;
- said lock core device further including a spring-loaded tumbler unit, said lock casing being formed with a first tumbler hole, said inner shell being formed with a second tumbler hole, one of said locking plates being formed with a third tumbler hole, said first, second and third tumbler holes being aligned with one another prior to insertion of said key into said key hole, said tumbler unit including a first tumbler member received in said first tumbler hole, a second tumbler member received in said second tumbler hole, a third tumbler member received in said third tumbler hole, and a first biasing spring for biasing said first, second and third tumbler members to move inwardly to enable said first tumbler member to project into said second tumbler hole in said inner shell so as to hinder rotation of said inner shell relative to said lock casing, to enable said second tumbler member to project into said third tumbler hole in said one of said locking plates so as to hinder rotation of said one of said locking plates within said inner shell, and to enable said third tumbler member to project from said inner periphery of said one of said locking plates, said curved surface on said shank portion of said key being formed with a tumbler recess that is defined by a recessed tumbler push wall, said third tumbler member projecting into said tumbler recess when said key is inserted into said key hole, said third tumbler member being pushed by said tumbler push wall in a direction against biasing action of said first biasing spring so as to retract said second tumbler member into said second tumbler hole in said inner shell, thereby preventing said second tumbler member from hindering rotation of said one of said locking plates relative to said inner shell, and so as to retract said first tumbler member into said first tumbler hole such that said first tumbler member ceases to hinder rotation of said inner shell relative to said lock casing;
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- said inner shell of said lock core having an inner surface which is formed with a circumferential groove that extends circumferentially along a curved line on said inner surface of said inner shell, said third tumbler hole in said one of said locking plates being provided with a mounting sleeve through which said third tumbler member extends, said tumbler unit further including a second biasing spring received in said mounting sleeve and disposed around said third tumbler member for biasing said third tumbler member to move outwardly, said third tumbler member moving outwardly and extending into said circumferential groove, due to biasing action of said second biasing spring, for disengaging from said key when said key is inserted into said key hole to align said tumbler recess with said tumbler unit and when said key is rotated for moving said lock core to the unlocking position.