Restricted key system

Abstract

A restricted key system providing keys/key slots with an angled or chevron shaped cross sectional profile. Each key blade of the restricted key system includes an upper planar portion which is bitted or cut to position the standard pin tumblers, an intermediate portion which forms a horizontal ledge, and a lower planar portion which extends from the intermediate portion at an angle in the range of 5°-85° relative to the upper planar portion. The horizontal ledge of the key blade may be provided with at least two additional bitting surfaces for wards, tumblers and/or other key differing elements.

What is claimed is: 
     
       1. A key blank comprising: a) a bow member adapted to be grasped by fingers of a user, and   b) an elongate blade extending outwardly from the bow member and defining, in transverse cross section, an upper planar blade portion extending inwardly from one longitudinal edge of the blade, and   a lower planar blade portion extending inwardly from another, opposite longitudinal edge of the blade and adjoining an innermost edge of the upper blade portion in an intermediate .Iadd.ledge .Iaddend.portion of the blade,     c) wherein: the plane of the upper blade portion is oriented at a predetermined angle, in a range of 5° to 85° relative to the plane of the lower blade portion to define a general chevron shape therewith.     
     
     
       2. The key blank according to claim 1, wherein said upper planar portion includes a bitting surface along said one longitudinally edge of said blade. 
     
     
       3. The key blank according to claim 1, wherein said intermediate .Iadd.ledge .Iaddend.portion includes a horizontal ledge, said horizontal ledge having a bitting surface disposed directly under and along said horizontal ledge of said blade. 
     
     
       4. The key blank according to claim 2, wherein said intermediate .Iadd.ledge .Iaddend.portion includes a horizontal ledge; and further comprising an additional bitting surface disposed directly under and along said horizontal ledge of said blade. 
     
     
       5. The key blank according to claim 1, wherein said intermediate .Iadd.ledge .Iaddend.portion includes a horizontal ledge, said horizontal ledge meeting an outer surface of said upper planar portion at a corner portion; and further comprising a bitting surface disposed along said corner portion. 
     
     
       6. The key blank according to claim 2, wherein said intermediate .Iadd.ledge .Iaddend.portion includes a horizontal ledge, said horizontal ledge meeting an outer surface of said upper planar portion at a corner portion; and further comprising an additional bitting surface disposed along said corner portion. 
     
     
       7. The key blank according to claim 1, wherein said predetermined angle is in a range of 15° to 45°. 
     
     
       8. A cylinder lock comprising: a lock cylinder having a cylindrical bore formed therein;   a key barrel rotatably mounted within said cylindrical bore;   a first set of bores formed in said key barrel on a radial plane;   a plurality of pins slidably disposed in said first set of bores;   a key slot extending longitudinally in said key barrel for receiving a key and intersecting said first set of bores;   a second set of bores formed in said lock cylinder; and   a plurality of tumbler pins slidably disposed in said second set of bores;   wherein said key includes an elongate blade defining in cross section: an upper planar blade portion extending inwardly from one longitudinal edge of the blade, and a lower planar blade portion extending inwardly from another, opposite longitudinal edge of the blade and adjoining an innermost edge of the upper blade portion in a intermediate .Iadd.ledge .Iaddend.portion of the blade, wherein the plane of the upper blade portion is oriented at a predetermined angle, in a range of 5° to 85° relative to the plane of the lower blade portion to define a general chevron shape therewith; and further wherein said key slot is similarly shaped in cross section so as to receive said blade.   
     
     
       9. The cylinder lock according to claim 8, wherein said intermediate .Iadd.ledge .Iaddend.portion of said blade includes a horizontal ledge, said horizontal ledge having a bitting surface disposed directly under and along said horizontal ledge of said blade; said lock cylinder further comprising an additional set of bores disposed directly under a portion of said key slot opposite to said horizontal ledge, said additional set of bores being filled with carbide pins.   
     
     
       10. The cylinder lock according to claim 8, wherein said lock cylinder includes a key removable core subassembly, said core subassembly having a figure-8 shaped cross section and being fitted into a like-shaped opening in said lock cylinder, said cylindrical bore for rotatably mounting said key barrel being formed within said core subassembly. 
     
     
       11. The cylinder lock according to claim 8, wherein said intermediate .Iadd.ledge .Iaddend.portion of said blade includes a horizontal ledge, said horizontal ledge meeting an outer surface of said upper planar portion at a corner portion, said corner portion having a further bitting surface formed thereon; said lock cylinder further comprising a further set of bores disposed along a portion of said key slot opposite to said corner portion of said blade, said further set of bores being filled with further set of tumbler pins for engaging said further bitting surface of said blade. 
     
     
       12. The cylinder lock according to claim 8, wherein said predetermined angle is in a range of 15° to 45°. 
     
     
       13. The cylinder lock according to claim 8, wherein said key blade having said general chevron shape defines nine profile surfaces to attendantly provide for additional key blank differing. 
     
     
       14. A cylinder lock comprising: a lock cylinder having a cylindrical bore formed therein;   a key barrel rotatably mounted within said cylindrical bore;   a first set of bores formed in said key barrel on a radial plane;   a plurality of pins slidably disposed in said first set of bores;   a key slot extending longitudinally in said key barrel for receiving a key and intersecting said first set of bores;   a second set of bores formed in said lock cylinder; and   a plurality of tumbler pins slidably disposed in said second set of bores;   wherein said key includes an elongate blade defining in cross section: an upper planar blade portion extending inwardly from one longitudinal edge of the blade, and a lower planar blade portion extending inwardly from another opposite longitudinal edge of the blade and adjoining an innermost edge of the upper blade portion in an intermediate portion of the blade, wherein the plane of the upper blade portion is oriented at a predetermined angle relative to the plane of the lower blade portion to define a general chevron shape therewith; and further wherein said key slot is similarly shaped in cross section so as to receive said blade, wherein said intermediate portion of said blade includes a horizontal ledge, said horizontal ledge having a groove disposed directly under and extending longitudinally along said horizontal ledge of said blade;   said lock cylinder further comprising an additional set of bores disposed directly under a portion of said key slot opposite to said horizontal ledge, a corresponding one of said additional set of bores being filled with a carbide warding pin for registering with said groove, and   further wherein said groove extends from a tip of said blade to such a length so as to allow said key to fully enter said key slot. .Iadd.   
     
     
       15.  A key for a cylinder lock, the key having a bow portion to be grasped by the fingers and a key blade for entering a complementary shaped key slot, the key blade being functionally longitudinally divided horizontally with a planar upper portion bitted on its upper surface to position tumblers in the same plane as the planar upper portion, and a lower portion extending at an angle of between 5° and 85° relative to the plane of the upper portion, the upper and lower portions being joined at an intermediate horizontal ledge portion which includes at least one flat surface for presenting additional new key differing possibilities and preventing the key from entering a key slot other than those having a complementary angled shape. .Iaddend..Iadd. 
     
     
       16.  A cylinder lock and key combination comprising: a lock cylinder having a cylindrical bore formed thereon,   a key barrel rotatably mounted in the cylindrical bore,   a set of tumbler pin holes formed in the key barrel on a radial plane,   a plurality of tumbler pins slidably disposed in the set of bores,   a key slot extending longitudinally of the key barrel for receiving a key and intersecting with the bores, the key slot being configured with an upper slot portion and a lower slot portion, the lower slot portion being oriented at a predetermined angle in the range of 5° to 85° relative to the plane of the upper slot portion,   and a key having a key blade with an upper planar portion and a lower planar portion, the angle between the two planar portions of the key blade being the same as the angle between the two portions of the key slot so that the blade fits into the slot, wherein the upper and lower planar portions are joined by an intermediate horizontal ledge portion, and the upper edge of the upper blade portion is bitted to properly position the tumbler pins in the tumbler pin holes to operate the cylinder lock. .Iaddend.