Idea For A Spring-Loaded, User-Friendly Safety Pen

[Synnove]

Given my love of large flex nibs and Iron Gall ink, I've fallen in love with the idea safety pens; no more concerns about ink drying out of large feeds, leaving behind a clogging mess that requires constant attention, priming, washing. Pen can be thrown in a bag without worry of jostling resulting in a large amount of ink in the cap.

 

Unfortunately no one makes them anymore. It's admittedly a niche market; they require a good amount of machining to make, and worst of all, require some effort on the part of the user to extend and retract the nib (i.e. people are lazy).

 

I've had a design stewing in my brain for a little bit concerning a safety pen that would extend and retract as a result of removing or putting on the cap due to spring pressure, removing the need for machining complex parts and removing some user effort from the writing.

 

Basically, is almost exactly the same as the Moore Safety design but with three key differences. First look at Binder's article on safety pens: http://www.richardspens.com/?page=ref/anatomy/safeties.htm

 

1: There is a spring inside the barrel between the nib collar and the packing plug at the rear of the barrel; it will try to push the nib collar (and by extension, the carrier rod) away from the rear of the barrel, causing the nib to be extended.

 

2: There is a sturdy pin inside the cap (likely titanium) that will make contact with the feed as the cap is screwed on; as the cap is screwed on, the pin will put pressure on the feed, nib collar, carrier rod, forcing them rearward towards the plug in the barrel (the spring will compress). Likewise, when the cap is unscrewed, the pin retracts with the cap, and the spring is allowed to extend, bringing the nib collar, feed, rod, etc forward.

 

3: To make sure there is a tight seal, as well as providing a way to lock the nib collar back so as to fill the pen, a cutout is made in the slide with two locking positions. A small protrusion on the barrel will cam inside this cutout. Once the cap is off, the nib can be locked forward by pushing the sleeve forward and rotating the barrel protrusion in to a small locking hole by rotating the sleeve. To fill the pen, the cap needs to be off and the nib needs to be retracted. To do this: the sleeve is pulled backward and rotated to lock the protrusion in to another small locking hole.

 

If you need clarification on these changes, please consult this terrible drawing that will likely confuse you more: http://i.imgur.com/qDpL9Q4.jpg

 

So as you can see: keeps the simplicity of the Moore system whilst mechanically locking the nib forward (as opposed to just friction in the moore system) and adding automatic nib extension and retraction.

 

Are there any details or concepts that I'm missing here? If this was prototyped, any reason it wouldn't work? Should I just stick with a Waterman style safety or is this worth exploring?

Edited March 2, 2017 by Synnove

[Jamesbeat]

It's very clever, but I don't really understand what the point is?

 

As it says in the article that you linked to, the retractable nib safety pen design was superseded by the invention of the inner cap.

The inner cap does the same thing as a safety but with fewer moving parts and no seals to go bad.

 

There's an illustration in the article, but perhaps it would help to show a real world example.

 

The photo shows a Duofold replica that I made recently.

 

Apologies for the poor quality of the photo (I'm at work) and the unfinished inner cap that still shows machining marks.

 

I have positioned the inner cap over the nib as it would be when the pen is capped.

 

As you can see, it is actually the inner cap (black) that does all the work of sealing the pen - the cap itself (yellow) really just serves as a way to position the inner cap and clamp it against the flat face of the section.

That's why the cap has a hole in it - it is designed to equalize the air pressure as soon as the cap is loosened to prevent ink being sucked out of the nib/feed as the cap is unscrewed.

 

Providing the opening of the inner cap and the front of the section are machined correctly, the inner cap being clamped against the front of the section provides a very good seal.

As the pen wears in and the parts mate to each other, the seal will get even better.

 

Edited March 2, 2017 by Jamesbeat

[Synnove]

It's very clever, but I don't really understand what the point is?

 

There are two big advantages with a safety pen:

 

1: The nib is only exposed to the air when writing. When the cap is closed, the nib and feed are immersed in ink and cannot dry out. This allows one to use inks that would otherwise dry and gum up a fountain pen (I've heard of Walnut ink and India ink being used). I personally would love it for my iron gall inks as I wouldn't have to wash the pen and feed out so regularly, and the feed would always be primed, ready for flex writing as soon as the pen is opened.

 

2: Since the cap seals the ink in the barrel, no matter how much you shake the pen or toss it about, ink will not fly out of the feed and in to the cap. I don't mistreat my pens, but I do tend to toss one in my backpack pocked (a lined pocket just for them, of course) and hope it doesn't make a mess while I heave the backpack here and there. This is especially headache inducing with flex pens that have few fins on the nib; a little shake and ink can just shoot out.

[Jamesbeat]

Ah, I didn't know about the nib and feed being immersed when the pen was closed - I thought they had a sliding seal inside the barrel.

I guess that explains why ink doesn't shoot out when you close them

 

As I said, your idea is very clever and looks like it would work well.

Could you maybe make the pi inside the cap impinge upon the edge of the section instead of the feed? That might make it less complex.

Stainless steel would be fine for the pin by the way - it's plenty strong enough and if it works for nibs it must be ink proof.

[Goudy]

Interesting idea. One issue that occurs to me, though, is that uncapping the pen against the force of a strong spring could involve a certain risk factor for the user - like unscrewing the cap on a bottle of Pepsi after you've given it a good shake. One way to avoid the problem would be to have a very long thread on the cap, so that the nib is fully extended by the time the user has fully unscrewed the cap. But that would necessarily involve as much effort as operating the standard safety screw mechanism.

 

Another pen that has a spring mechanism operated by the cap is the Ford's Patent Pen - but in that case the travel of the spring is much shorter, its purpose being to open and close a seal rather than extend the nib.

 

 

1: The nib is only exposed to the air when writing. When the cap is closed, the nib and feed are immersed in ink and cannot dry out. This allows one to use inks that would otherwise dry and gum up a fountain pen (I've heard of Walnut ink and India ink being used). I personally would love it for my iron gall inks as I wouldn't have to wash the pen and feed out so regularly, and the feed would always be primed, ready for flex writing as soon as the pen is opened.

 

Unfortunately, iron gall inks (the non FP-friendly types) can precipitate even in a sealed container. Take a look at the bottom of a bottle of ESSRI or Diamine Registrar's after you've been using it for a few weeks. I've tried Diamine Registrar's Ink in a safety pen and wouldn't advise it. The sediment gets into the mechanism and causes it to snag. It's also a pain to flush out.

 

I'm a big fan of vintage safeties. I don't think any other design is as good at avoiding ink leakage: a closed safety is effectively a sealed ink bottle with a nib inside it. The problem with the inner cap system is that it can fill up with ink and give the user a dousing when the pen is uncapped.

[Driften]

It just seems like there are simpler systems, like an eyedropper with an shutoff valve like some japanese pens? Or a vac filler where you can close the valve?

[Moonshae]

I'd be concerned about a piece of metal rubbing against the feed every time the pen is capped/uncapped. Ink may lubricate to some extent, but if you have metal rubbing on plastic, eventually it is going to cause wear and the nib won't fully retract. I'm not sure if this will lead to leakage from the design.

 

Also, if IG inks can corrode steel nibs, I'm not sure having the whole nib immersed in the ink most of the time (assuming a pen spends more time capped than not) will be good for the nib or reduce the need for cleaning.

[Goudy]

Also, if IG inks can corrode steel nibs, I'm not sure having the whole nib immersed in the ink most of the time (assuming a pen spends more time capped than not) will be good for the nib or reduce the need for cleaning.

 

Vintage safeties had gold nibs, which have survived for close to a century. But stainless steel is also resistant to the acid in iron gall. I have a Kaweco AL Sport that I use exclusively with Diamine Registrar's (IG) and there's no trace of corrosion on the nib after more than a year.

 

On the other hand, a bare steel dip nib on any kind of fountain pen loaded with any kind of ink is bound to corrode quickly.

[Polanova]

I discovered Safety Pens myself lately. One can use Iron Gall inks and India ink in a Safety, but I recommend to give them a good flush after use (you can keep regular ink for months and years in a safety).

 

I wasn`t aware of the special features of the Moore pen - it reminds me of a Safety Model, which Stylomine has produced in France during the early 30ies. The latter also had the nib on a spring and it used a bulb for filling, so no cork or o-rings were needed, which sounds quite clever to me!***

 

Actually I fantasize on occasion to have a customized replica built (in transparent red acryl with gold trims )

 

***There`s a construction drawing in Lambrou`s "FP`s Vintage and Modern"

[Bo Bo Olson]

India ink....I'm sure will =, once I had a safety pen.