Resilient plastic staple

Claim 1

A staple formed from a resilient plastic material having an elastic memory and adapted to be driven by a stapling gun or the like for use in fastening relatively soft work material such as cellular or foam plastic, corrugated cardboard, and the like, said staple comprising: a pair of preformed, substantially straight, and normally nonparallel leg portions; and a preformed crown portion integrally connecting said leg portions so that said leg portions are each normally inclined from parallel position at an angle of up to about 25*; each of said leg portions having a preformed reversely extending barb projecting angularly in substantially rigid relation from the free end of the leg portion and defining a sharp point at said free end for penetrating the work material during driving of the staple, said barb being adapted to form a clearance between the leg portion and the surrounding work material as the leg portion penetrates the work material; each of said barbs being integrally joined with its leg portion solely at the outermost surface of the leg portion; and said leg portions being deflectable momentarily to substantially parallel relation before and during penetration of the staple into the work material and thereafter returning toward their normal non-parallel position, by reason of said elastic memory, and thereby embedding said barbs in the work material, the return of said leg portions toward their non-parallel position being facilitated by the clearances formed by said barbs during penetration of the leg portions into the work material.