Jump to content

Fountainbel OS "PF Tribute" plunger fill fountain pen


fountainbel

Recommended Posts

Hi G,

Thanks for your suggestion!

I've already played with this idea, but due to the cap locking system this is unfortunately not possible.

Nevertheless I'll gladly send you a PM with my private E-mail, one never knows if I have overseen something.

I could make the cap ring less wide, but then the total cap would also be proportionally shorter, and I think the capped cap/ barrel ratio is now aesthetically optimum.

Thanks again & regards, Francis

 

 

 

Francis,

 

Would it be possible to thin down the cap ring so that you could extend the cap over the ring? I would think that if this were possible, you could make the ring as narrow/wide as you like.

 

Cheers... G

 

P.S. - I have a quick & dirty sketch of this idea, but no idea how to get said sketch to you other than email. pm me with your email addy & I'll send it to you.

 

Link to comment
Share on other sites

  • Replies 44
  • Created
  • Last Reply

Top Posters In This Topic

  • fountainbel

    12

  • Michael R.

    6

  • Dr.Grace

    3

  • Rapt

    3

Very interesting to read on your practical experiences with the Visconti double reservoir system Shabubu, much appreciated !

As I understand the ink front ink reservoir is to small to allow a decent amount of writing given the special nib( & feed ) installed?

Could you please clarify this somewhat more?

I've also read on another tread that some users are not happy with the fact that emptying the front reservoir is very difficult, is this also your experience?

Best regards, Francis

 

 

Pilot uses a straight forward vacuum filler with an ink shutoff valve, as in the Onoto. The patent on this type of filler will be well expired, and so I wouldn't be concerned about using it. The Visconti double reservoir system, AFAIK is still covered by patent and as they are so proud of it I would not try using it. The only thing about the double reservoir system is that it tends to be more an annoyance than a usefull feature. The normal ink shutoff valve is adequate for air travel, and the reservoir on my wall street is too small for the hose that is the Binder Itallifine attached to it. Using the "straight forward" vacuum filler should simplify manufacture, increase the ink capacity and improve your nights sleep ;)

 

If you did want to persist with the "double reservoir" then there are a few ways to do it, firstly never reference it in a description, Visconti use the design as a selling point and would be upset if you did the same. Secondly if the reserve resevoir is part of the screw in assembly as opposed to a distinct chamber then you would be ok. I can't see enough of your designs to see if this is the case, but in the visconti the plunger stops a significant distance from the feed, and as such the first of the two resevoirs is a discrete manufactured unit. If in your pen this area was left for "manufacturing reasons" rather than as a feature you should be able to escape any patent problems.

 

I would also like to add my name to the list for one of these, though cannot decide which material would be best (though would love to see a 'sailor king of pen' version, no trim and black hard rubber).

 

Link to comment
Share on other sites

The feed is standard, but the nib is reground from a broad to a itallifine. It was similar prior to the customisation, but is more pronounced now. The plunger on the filler doesn't seem to break the seal after being fully unscrewed and so flow is only really good enough when the blind cap is pulled an extra 2-3mm. Basically the flow gets really stingy after two paragraphs, and so I just tend to write with the blind cap fully unscrewed. I find the same with emptying the front resevoir, it requires an extra few millimeters of pull on the blind cap after it's fully unscrewed in order to allow the ink back out. I can see what they were hoping to achieve with the system, but you have to empty the resevoir prior to travel (or flying), and as such I cannot see what is gained above the standard vacuum fill and ink shutoff of the onoto (and subsequent Pilot 823) system.

Edited by Shabubu

"Over the centuries, mankind has tried many ways of combating the forces of evil... prayer, fasting, good works and so on. Up until Doom, no one seemed to have thought about the double-barrel shotgun. Eat leaden death, demon... "

Terry Pratchett

Link to comment
Share on other sites

Thanks Shabubu, I clearly see the problem now.

Most probably the piston seal - which also functions as shut-off valve & check valve- tends to stick to its shut-off surface on the section.

The axially low flexible piston seal is fitted axially floating on a conical seat over a restricted stroke of 1 -1.5mm , being only tight when pushing the plunger down. This feature is not shown on the Visconti simulation, it is however clearly shown on the patent drawing ( patent US 6,250,832 B1- sheet 3)

When pulling the plunger out, the piston seal will normally get stuck radially as soon as the seal leaves the enlarged filling chamber and enters the normal - narrower- piston chamber. At this moment only the plunger moves , till - after a further 1-1.5mm stroke -the front plunger collar contacts the seal & both move further backwards again. At this moment the ink in the reserve chamber -behind the seal - can flow back to the filling chamber (hence out of the pen) through the conical gap created between the seal bore and its plunger seat. In fact the axially floating piston seal acts like a check-valve.

Potential draw back- proven by your experiences- is the fact that the seal can stick to its shut-off back-up surface, since one needs a 1 -1.5 mm stroke to pull the seal effectively from its back-up surface on the section.

A little confusing though, since one should expect the ink can still flow through the conical gap between the seal bore & its seat when screwing the plunger 1mm out, even with a sticking shut-off.

Given your experience it looks the seal not only sticks on its back-up surface on the section, but also sticks on its conical plunger seat.

Aiming for a positive shut-off, while coping with barrel & plunger rod length tolerance variations, Visconti most probably applied a nominal 0.2/0.3mm axial pretension of the piston seal on its barrel back-up surface. This logically implies that the plunger has to be screwed open at least 0.3 mm before the seal can break from its seat. And even then, given the potential "double" sticking situation, the rubber seal will only axially deform a little when opening the plunger 0.3mm -remaining sticking on both surfaces- and not allowing any ink flow.

Only screwing the plunger further out will break the sticking , at least on one of the "sticking" surfaces.

Both sticking surfaces will only break positively loose after the axial plunger collar effectively pulls the seal backwards.

I hope this clarifies the problems you encounter, problems which seem effectively inherent to the "triple function combination" of piston seal, check valve & shut-off valve.

Splitting these functions- as Onoto did & I would do using modern sealing techniques- would surely overcome these problems.

Thanks again for your very informative posting, it really opened my eyes!

Regards, Francis

 

Edited for completion

 

The feed is standard, but the nib is reground from a broad to a itallifine. It was similar prior to the customisation, but is more pronounced now. The plunger on the filler doesn't seem to break the seal after being fully unscrewed and so flow is only really good enough when the blind cap is pulled an extra 2-3mm. Basically the flow gets really stingy after two paragraphs, and so I just tend to write with the blind cap fully unscrewed. I find the same with emptying the front resevoir, it requires an extra few millimeters of pull on the blind cap after it's fully unscrewed in order to allow the ink back out. I can see what they were hoping to achieve with the system, but you have to empty the resevoir prior to travel (or flying), and as such I cannot see what is gained above the standard vacuum fill and ink shutoff of the onoto (and subsequent Pilot 823) system.
Edited by fountainbel
Link to comment
Share on other sites

Big disappointment today, I was told by a visiting Belgian collector that the system with the 2 separated ink chambers already exists & is used by Visconti....

I've just checked the site & although their patented system is not fully identical,it looks quiet similar.

I was not aware off this, I was simply inspired by the shut-off valve Onoto already used in the thirties & optimized this idea.

In fact I was happily surprised when seeing that one obtains 2 ink chambers with this approach.

Unfortunately it looks that I was not the first one who discovered this.

While Visconti uses the piston seal both for pulling the ink up & as as shut-off valve, I use a separate sealing element or both functions.

It looks that I could have a patent infringement problem when selling the Tribute......, see below

http://www.visconti.it/double.htm

 

Disappointing, but this is live.

At least it was fun to design & make my own plunger filler!

Thanks to all of you for your suggestions & positive comments, it surely encouraged me to make the various versions.

Regards, Francis

 

 

I'm sorry to hear that this might cause problems selling your pen :-(

 

There are some good sugestions how to check on those patents.

 

Maybe a classic style Shaffer Vac-Fil would do as well in case this does not interfer with any patents.

 

 

It would be a pitty NOT to see your pen in production because of this.

 

Please keep us updated....

 

 

 

Cheers

 

Michael

 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Most Contributions

    1. amberleadavis
      amberleadavis
      43844
    2. PAKMAN
      PAKMAN
      33494
    3. Ghost Plane
      Ghost Plane
      28220
    4. inkstainedruth
      inkstainedruth
      26624
    5. jar
      jar
      26101
  • Upcoming Events

  • Blog Comments

    • Shanghai Knife Dude
      I have the Sailor Naginata and some fancy blade nibs coming after 2022 by a number of new workshop from China.  With all my respect, IMHO, they are all (bleep) in doing chinese characters.  Go use a bush, or at least a bush pen. 
    • A Smug Dill
      It is the reason why I'm so keen on the idea of a personal library — of pens, nibs, inks, paper products, etc. — and spent so much money, as well as time and effort, to “build” it for myself (because I can't simply remember everything, especially as I'm getting older fast) and my wife, so that we can “know”; and, instead of just disposing of what displeased us, or even just not good enough to be “given the time of day” against competition from >500 other pens and >500 other inks for our at
    • adamselene
      Agreed.  And I think it’s good to be aware of this early on and think about at the point of buying rather than rationalizing a purchase..
    • A Smug Dill
      Alas, one cannot know “good” without some idea of “bad” against which to contrast; and, as one of my former bosses (back when I was in my twenties) used to say, “on the scale of good to bad…”, it's a spectrum, not a dichotomy. Whereas subjectively acceptable (or tolerable) and unacceptable may well be a dichotomy to someone, and finding whether the threshold or cusp between them lies takes experiencing many degrees of less-than-ideal, especially if the decision is somehow influenced by factors o
    • adamselene
      I got my first real fountain pen on my 60th birthday and many hundreds of pens later I’ve often thought of what I should’ve known in the beginning. I have many pens, the majority of which have some objectionable feature. If they are too delicate, or can’t be posted, or they are too precious to face losing , still they are users, but only in very limited environments..  I have a big disliking for pens that have the cap jump into the air and fly off. I object to Pens that dry out, or leave blobs o
  • Chatbox

    You don't have permission to chat.
    Load More
  • Files






×
×
  • Create New...