Tamper-proof threaded fastenings

Abstract

The fastening device has a head portion with a uniform cross section, the uniform cross section having a plurality of non-uniform indentations. A matching socket wrench is provided having an internal cross section matching the exterior cross section of the fastening for tightening or loosening the fastening. The invention is particularly useful for preventing unauthorized removal of automobile wheels.

I claim: 
     
       1. An anti-theft fastening device for securing an automobile wheel to a vehicle, said fastening device including a head portion defining a predetermined configuration on the outer periphery thereof adapted to complement the configuration of a tool for removing said head portion from an automobile wheel, and a cap .[.removable.]. .Iadd.removably .Iaddend.mounted over said head portion to conceal said predetermined configuration defined on said head portion, the combined weight of .Iadd.the fastening device including .Iaddend.said head portion and said cap being substantially equal in weight to the weight of conventional lug nuts mounted to said automobile wheel. 
     
     
       2. The device as claimed in claim 1 wherein said cap is designed to resemble the configuration of said conventional lug nuts mounted to said automobile wheel. 
     
     
       3. The device as claimed in claim 1 wherein screw threads are defined on at least part of the outer periphery of said head portion and on at least part of the inner surface of said cap for screwing said cap over said head portion. 
     
     
       4. The device as claimed in claim 1 wherein said predetermined configuration on said head portion is defined by a plurality of indentations. 
     
     
       5. A fastening device as claimed in claim 4 wherein an odd number of at least three of said indentations are provided. 
     
     
       6. A fastening device as claimed in claim .[.5.]. .Iadd.4 .Iaddend.wherein said indentations are non-uniform from one set of fastening devices to another. 
     
     
       7. A fastening device as claimed in claim .[.6.]. .Iadd.4 .Iaddend.wherein said .[.non-uniform.]. indentations are non-uniform in the sense that the circumferential spacing of said indentations is non-uniform. 
     
     
       8. A fastening device as claimed in claim .[.6.]. .Iadd.4 .Iaddend.wherein said .[.non-uniform.]. indentations are non-uniform in size. 
     
     
       9. A fastening device as claimed in claim .[.6.]. .Iadd.4 .Iaddend.wherein said .[.non-uniform.]. indentations are non-uniform in number. 
     
     
       10. A fastening device as claimed in claim .[.6.]. .Iadd.4 .Iaddend.wherein said .[.non-uniform.]. indentations are non-uniform in shape. 
     
     
       11. A fastening device as claimed in claim .[.6.]. .Iadd.4 .Iaddend.wherein said .[.non-uniform.]. indentations are non-uniform both in spacing and in size. 
     
     
       12. A fastening device as claimed in claim .[.6.]. .Iadd.4 .Iaddend.wherein said .[.non-uniform.]. spacing and shape. 
     
     
       13. A fastening device as claimed in claim .[.6.]. .Iadd.4 .Iaddend.wherein said .[.non-uniform.]. indentations are comprised of grooves. 
     
     
       14. A fastening device as claimed in claim 13 wherein said grooves have a substantially V-shaped cross section. 
     
     
       15. A fastening device as claimed in claim 13 wherein said grooves have an arcuate cross section. 
     
     
       16. A fastening device as claimed in claim 6 in combination with a socket wrench for engagement over the head of said fastening device and having radially inwardly extending protrusions arrangeed and adapted for engagement within said indentations in said head portion of said fastening device. 
     
     
       17. A fastening device as claimed in claim 1 wherein said cap is metallic. 
     
     
       18. A fastening device as claimed in claim 17 wherein said cap is aluminum. 
     
     
       19. A fastening device as claimed in claim 1 wherein the bottom of said head portion defines a radial flange having a larger diameter than that of said cap. .Iadd. 
     
     
       20.  An anti-theft lug fastener for a vehicle wheel to be used in place of a standard threaded lug fastener of the type adapted to receive a standard lug wrench for rotation thereof for installation and removal, the anti-theft lug fastener comprising a threaded lug fastener body, the lug fastener body having a generally circular head portion with an annular arrangement of a plurality of angularly spaced and axially extending peripheral grooves non-uniformly angularly spaced to receive a non-standard lug wrench for rotation of the lug fastener body for installation and removal, the lug fastener body having an externally threaded portion and the anti-theft lug fastener further comprising an internally threaded outer end cap threadably mounted on said threaded portion to conceal an outer end portion of the lug fastener body including said head portion, the lug fastener cap having an external appearance simulating the external appearance of a corresponding outer end portion of said standard lug fasteners provided for certain vehicles, the weight of the anti-theft lug fastener, including the weight of the lug fastener body and the lug fastener cap, being substantially the same as the weight of a said standard lug fastener for said vehicles. .Iaddend. .Iadd.21. An anti-theft lug fastener according to claim 20, wherein the lug fastener cap has a portion with an exterior hexagonal shape simulating being adapted to receive a standard lug wrench for rotation of the anti-theft lug fastener for installation and removal. .Iaddend. .Iadd.22. An anti-theft lug fastener for wheels of certain vehicles to be used in place of a standard threaded lug fastener for said wheels of the type adapted to receive a standard lug wrench for rotation thereof for installation and removal, the anti-theft lug fastener comprising a threaded lug fastener body, the lug fastener body having a generally circular head portion with an annular arrangement of a plurality of angularly spaced and axially extending peripheral grooves non-uniformly configured to receive a non-standard lug wrench for rotation of the lug fastener body for installation and removal, the lug fastener body having an externally threaded portion and the anti-theft lug fastener further comprising an internally threaded outer end cap threadably mounted on said threaded portion to conceal an outer end portion of the lug fastener body including said head portion, the lug fastener cap having an external appearance simulating the external appearance of a corresponding outer end portion of said standard lug fastener for said vehicles, the weight of the anti-theft lug fastener, including the weight of the lug fastener body and the lug fastener cap, being substantially the same as the weight of a said standard lug fastener for said vehicles. .Iaddend.