Copyright © Françoise Herrmann
Have you ever noticed how a regular smooth-wire paper clip sometimes just slips off the surface of the paper? Collette clips, named after the American inventor Clarence Charles Collette, are designed with serrations, precisely to resolve this issue, and to securely grip together various sheets of paper.
The Collette clip, as disclosed in the May 17, 1921 patent US1378525, titled Paperclip was introduced as follows:
invention has for its object to produce a means for securing a plurality of sheets together,
commonly known as a paper clip wherein are formed sharply pointed projections for
penetrating and engaging the sheet material, such as paper, to prevent removal of the clip or the separation of one or more of the
sheets from the
dip. In my
projecting points are located on the opposite sides of a bent clip having its parts preferably
located in the same plane, it being particularly adaptable to a clip which is of the
form of a
oblong spiral well known in the stationary arts."
The Collette clip was also disclosed in the 1922 British Patent GB182567 titled Improvements to paperclips, this time introduced in contrast to the original paperclip as:
“The invention relates to means for clipping together a plurality of sheets of paper or the like and has particular reference to clips of the kind which comprise a length 'of resilient metal wire bent to form two U-shaped portions one of which lies within and in the same plane as the other, one limb of the one U being connected to the remote limb of the other U.”
And in both patents, the invention also includes disclosure of the means by which the serrations are produced, at strategic offset positions, on opposite sides of the clip, using a sharp instrument.