They Invented What? (No. 53)

U.S. Pat. No. 5,329,672:  Metal wire paper clip structure.

JW Note:  The paper clip – patented in 1994.  Many thanks to Michael Barclay at WSGR for bringing this one (and many others) to our attention! 

  

We claim:

1. A metal wire paper clip comprising 

         a unitary length of spring-quality metal wire bent into an elongated configuration presenting an elongated U-shaped inner loop, an elongated U-shaped outer loop, and an arcuately-curved interconnecting portion therebetween;   

          each such U-shaped loop having an open end, a closed end, and a pair of longitudinally-extending legs;

         such closed end of the elongated U-shaped outer loop defining one longitudinal end of such bent wire elongated configuration, such inner loop being nested within such outer loop with such open end of each such U-shaped loop facing in the same longitudinal direction;

         such pair of longitudinally-extending legs of each such U-shaped loop including a free leg having a distal end located at the open end of its respective U-shaped loop, and a connecting leg, such arcuately-curved interconnecting portion extending between such connecting legs at the open end of each such U-shaped loop and defining at its longitudinally outward midpoint the remaining longitudinal end of such bent wire configuration;

          each such inner and outer loop free leg extending at least to the juncture of such longitudinally-extending connecting legs with such curved interconnecting portion while not extending beyond a location which is contiguous to a laterally transverse plane normal to the longitudinal axis of the clip which is longitudinally inward of a tangent to the longitudinally inward midpoint of the arcuately-curved interconnecting portion, and each such U-shaped loop and such curved interconnecting portion being substantially coplanar so that the paper clip lies substantially flat when not in use.

2. The structure of claim 1 having a length dimension between longitudinal ends of about three to about five inches and a lateral width dimension between said outer loop longitudinally extending legs of about one inch.

3. The structure of claim 2 in which such spring-quality metal wire comprises high carbon steel having a nominal diameter between about 0.08″ and 0.11″, with such steel having a protective surface finish.

4. The structure of claim 2 in which such spring-quality metal wire comprises medium hard to hard high-carbon steel cold drawn without anneal of about twelve to about 14 gage, such steel having a protective surface finish.

5. The structure of claim 2 in which such spring-quality metal wire comprises steel having a carbon content in the range above 0.30% C by weight to about 0.9% C by weight, with such steel having a protective surface finish.