Metal Spring Clip

A binder clip, less commonly known as a paper clamp or foldover clip or bobby clip, is a simple device for binding sheets of paper together. It leaves the paper intact and can be removed quickly and easily, unlike the staple. The term foldback clip is used in the United Kingdom to describe this invention (not to be confused with a Bulldog clip, an older device with the same function, which is stronger and has rigid rather than folding handles). It is also sometimes referred to as a “handbag clip” because, when not in use, its clip can be folded up to look like a handbag. This feature is used to hold the papers in place even better.

A binder clip is a strip of spring steel bent into the shape of an isosceles triangle with loops at the apex. Tension along the base of the triangle forces the two sides closed, and the loops prevent the sharp steel edges from cutting into the paper. The loops also serve to hold two pieces of stiff wire, which are used as handles and allow the clip to be opened. The two slots cut in each loop are shaped so that the wire handles can be folded down once the clip has been attached, and the spring force of the wire holds them down on the surface of the paper. This holds the clip relatively flat, for easier stacking of paper. One handle can also be folded down while the other remains up to allow the stack of papers to be hung up. The handles can also be removed altogether by squeezing them sideways and pulling them out, allowing for more permanent binding. As compared to a paper clip, the binder clip is able to bind sheets of paper more securely, and is also resistant to rust.

There are several sizes of binder clips, ranging from a base size of 5 millimetres (0.2 in) to 50 mm (1.97 in). The sheet steel portion is customarily black oxide coated, but a variety of decorative painted color schemes are also available. The sheet steel portion is occasionally made of stainless steel, the more typical spring steel can also be finished in nickel, silver or gold. The handles are normally nickel-plated.