Cylinder lock with a lock picking impediment

A cylinder lock having a lock housing with a cylinder adapted to accept a key and being rotatably mounted in the housing;

• a cylinder having at least one transverse boring corresponding to a boring in the housing with a cylinder pin disposed in the transverse boring and a spring biased locking pin disposed within the housing boring biased so that the locking pin is driven toward the cylinder and oriented so that the locking pin can enter the transverse boring, abutting an end of the cylinder pin, and thereby lock the cylinder from rotary movement;
• the cylinder pin being radially displaceable by a key and operative to drive the locking pin out of the cylinder boring thereby unlocking the cylinder;
• the improvement comprising:
• a plurality of spaced circumferential slots selectively located on the cylinder pin;
• a second boring in the cylinder disposed at an acute angle to and intersecting said transverse boring;
• tapered recess of selected shape selectively located, with respect to the second boring, in the housing;
• an obstruction pin in said second boring capable of limited movement in said second boring;
• whereby if said cylinder is rotated so as to jam the locking pin, said obstruction pin slidingly engages said tapered recess and moves inwardly due only to said sliding engagement and a first end of said obstruction pin engages one member of said plurality, of spaced circumferential slots blocking any radial movement by said cylinder pin.

An improved cylinder lock having a lock housing with a cylinder adapted to accept a key and being rotatably mounted in the housing;

• the cylinder having at least one transverse boring corresponding to a boring in the housing with a cylinder pin disposed in the transverse boring and a spring biased locking pin disposed within the housing boring biased so that the locking pin is driven toward the cylinder and oriented so that the locking pin can enter the transverse boring, abutting and end of the cylinder pin, and thereby lock the cylinder from rotary movement;
• the cylinder pin being radially displaceable by a key and operative to drive the locking pin out of the cylinder boring thereby unlocking the cylinder;
• the improvement comprising:
• the cylinder pin having a plurality of spaced circumferential slots thereon;
• a second boring in the cylinder disposed at an angle to and intersecting said transverse boring;
• a recess of selected shape selectively located with respect to the boring in the housing;
• an obstruction pin in said second boring capable of limited axial movement in said second boring;
• whereby if said cylinder is rotated so as to jam the locking pin, said obstruction pin slidingly engages said recess and moves axially inwardly in said second boring and a first end of said obstruction pin engages one member of said plurality, of spaced circumferential slots blocking any radial movement by said cylinder pin;
• wherein said cylinder pin has a shaped end region whereby when a legitimate key radially displaces said cylinder pin to unlock the lock, said shaped end region is operative to receive said first end of said obstruction pin permitting said obstruction pin to move radially allowing said cylinder to rotate;
• and
• wherein said first end of said obstruction pin comprises a planar surface transversely oriented with respect to said obstruction pin.

A cylinder lock having a housing with a cylinder rotatably mounted therein, at least one transverse radial boring in the cylinder with an adjacent boring extending into the housing of the cylinder when the cylinder is in a first angular position, with a cylinder pin in the transverse cylinder boring capable of limited axial movement in that cylinder, a locking pin in the boring in the housing adjacent an exterior end of said cylinder pin, and capable of extending into the cylinder boring to prevent rotation thereof but movable outwardly from the cylinder boring under the urging of the cylinder pin thereby permitting the cylinder to rotate, the improvement comprising:

• a plurality of circumferential grooves in a mid-section of the cylinder pin and a V-shaped spacing region near an interior end of the cylinder pin;
• a second boring in the cylinder at an acute angle to the transverse radial boring and intersecting the transverse boring at a mid-section thereof;
• p1 a tapered circular recess in the housing, of a selected depth, terminating in a rounded bottom surface having a selected curvature;
• an auxiliary locking pin located in said second boring and capable of limited axial movement with respect to said second boring;
• an auxiliary locking pin having a first end located adjacent said cylinder pin and forming a selected angle with a cylindrical body portion of said locking pin and having further a second, outwardly extending, curved end adjacent said circular tapered recess;
• only said recess and said second end of said auxiliary locking pin cooperating to drive said locking pin inward axially, with respect to said second boring, when said cylinder rotates a selected amount so that an edge of said first end of said locking pin blockingly engages a member of said plurality of circumferential grooves thereby blocking movement of said cylinder pin when said cylinder pin has not been positioned so as to unlock the cylinder, and, so that said first end of said locking pin slides adjacent said V-shaped spacing region when said cylinder pin has been positioned to unlock said cylinder.