Engineers Explain How Click Pens Work

Have you ever wondered how click pens work? So did I there have been many a time that I have sat at my desk idly clicking my ballpoint pen and passing the time away musing over how it makes its click.

I personally like the clicking noise a Parker ballpoint pen makes. When you press the button on a retractable Parker Jotter it has a reassuringly firm action and produces a distinct clicking sound. Anyway, I thought I would find out how a retractable pen works and was quite surprised at the amount of engineering that has gone into making a pen’s refill extend and retract from the barrel of a retractable ballpoint click pen.

How Click Pens Work

Click Pen Parts

A retractable click pen has three main parts that interact when you press the button. These are the cam body a plunger and stop members.

How Do Clicky Pens Work

 

The following sequence of events shows the interaction of the cam body plunger and stop members when operating a click pens mechanism.

  1. The click pens button is pushed which drives the plunger and the cam body downwards below the fixed stop members.
  2. The pens spring pushes the cam body up against the plunger which makes the cam body rotate 45 degrees and you can hear the first click.
  3. When you release the push button a spring at the top of the pen forces the plunger back up the pen which allows the cam body to rotate another 45 degrees and strike the blue stop members.
  4. There is now a second audible click and the pens refill is fully extended and locked in place ready to write.
  5. Pressing the push-button again restarts the sequence but this time the pen refill will be retracted when you release the push button.

There is a YouTube video in which an engineering professor explains how a retractable pen works and has become a bit of a viral hit. The simple 4:43 video from Bill Hammack – “engineerguy” on YouTube – had been viewed more than 1,172,995 times when I last checked.

In the video, Hammack uses a Parker Jotter and some 3D modeling graphics to describe the interplay between plunger, cam, and spring that extends and retracts the ink cartridge and produces that distinctive clicking noise.

Hammack is a professor in the chemical engineering department at the University of Illinois at Urbana-Champaign. He explained in an email to us why he used the Jotter for the video.

“We choose a Parker Jotter because it was iconic. It seems to be the earliest that was retractable, at least the one of the earliest that was mass-produced. It is familiar to many of our viewers.”

The video became such a hit that wire service Reuters sent out a brief news story, which is how I heard about it.

When I started poking around a little, I found a couple other intersections of pens and engineering that I thought was interesting.

  • Engineers at Tufts University have put together an entire lesson plan for primary school teachers to teach their students basic engineering by disassembling an ink pen. The reasoning:  “Performing reverse engineering by analyzing the interactions between parts contributes to a better understanding of how something works.”
  • In 2011, engineers from Seoul National University and Harvard University conducted a study of the hydrodynamics involved in putting ink on paper. Why? Because “understanding how to combine the dynamics of swelling and imbibition in soft porous media with the rate of deposition will allow us to create functional porous substrates by writing on ever-smaller scales—perhaps even rejuvenating the ink-pen in a different guise?”

We know exactly how you feel, engineers. They fascinate us too.

Who Invented the Click Pen

In 1888 John J Loud filed a patent for a ballpoint pen but it was never viable and worked better on leather than paper and it was not until the 1930’s when Lazio Biro produced the world’s first ballpoint pen.

This was followed up by Milton Reynolds who found a way around the copyright laws to make an improved version of Biros ballpoint pen which was known as the Reynolds Rocket.

First Click Pen Patent

Both Reynolds and Biros ballpoint pens were capped pens and the first commercial retractable click ballpoint pen was patented by an inventor called John F Sullivan on behalf of the Frawley Pen company in the  1950’s.

The Frawley Pen Company, founded in 1949 by Patrick J. Frawley, claims to have made the “first pen with a retractable ballpoint tip” in 1950

Meanwhile, these guys aren’t engineers, but they do have a cool video showing a ballpoint pen laying down ink in extreme close-up.

It’s in a Scandinavian language, but thankfully there are subtitles. Also some cool music. This one has been viewed nearly 650K times since it was posted in February.

Nice to see pens getting the glamour treatment.

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