Principles of operation

I was trying to make sense of the basic principles on which our favorite platens operate. Put together these simple animations to get some clarity.

C&P Pilot (and clones)

Kelsey, Adana

Baltimorean (and it’s many relatives)


More coming.

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Oprion Sir, nice research and Post(s), at a risk of jumping the gun, (for which I apologise in advance, if it should be so, or seen to be so!)
Your first 4 excellent diagrams are all variations of CLAMSHELL, with my pre-stated Apologies in mind, I am sure that many new devotees would get great benefit from an appraisal of, **PARALLEL APPROACH,** as in Vickobold, Auto Vic, Kobold, and the best bar none the COLT ARMORY PRESS, apparently unsurpassed since its conception
If my intrusive efforts are covered by the MORE COMING,
Again Apologies.!!

Some bed / platen arrangements here

To Mick

Thanks for the suggestion. I’ll make sure to pick Colt as my next target.

Truth to tell, I’ve only illustrated presses that I either own (Kelsey , SIgwalt), have been intimate with (Pilot), or seen in operation and was fascinated by (Liberty). Sadly, I can not claim much exposure with the parallel impression behemoths you described, and so will have to do a bit of digging to figure how they function.

To Mick (again)

As I mentioned, I don’t know much about the parallel impression presses (never seen one in real life) but here’s a first attempt at Colt Armoury (from what little imagery I could find on the web). Let me know if I got this right, and if any principal part is missing.

As is suggested by an alternate name, “rolling-sliding” platen, after the platen rolls to vertical, the last motion is a sliding approach parallel to the form. Note that the bearing on the platen is eccentric, which is the mechanism for throw-off.
It is “Colt’s Armory” by the way. The Colt’s gun company manufactured these for the originator Rev. Gally until his patents expired, then John Thomson shut Gally out. Gally’s platens were then made by National, who merged with Thomson after Gally died. Thomson-National still makes die-cutters of the same type.
I wouldn’t say the Colt’s version was unsurpassed, considering how very many improvements were made by Victoria, Phoenix, Bremner, and others across the Altantic. Colt’s never even came up with a feeder or automatic guides. Probably the top of the American line was the Laureate developed by National before the merger.

Oprion,Sir, glad you appreciated my little offering, the good buddy P.P. above has included one tiny reference, re parallel approach, Thank you Sir.
I hoped that you would do a little investigating and eventually, be able to give a resume, of Parallel Approach, for the benefit of the new devotees, primarily because Parallel Approach is generally accepted as being superior to Clamshell, if only because, Packing,and Impression etc., are so much more precise, by virtue of the, almost, infinitely variable, fine adjustment for make ready and impression i.e. one tweek,
+ or - makes the difference between perfect impression or otherwise??
Clamshell, is by its very nature is a fine balancing act and takes longer to achieve results and frustrating.?
Oprion Sir apologies if my ramblings give you a Bigger, headache, but I am sure that your eventual findings will be appreciated by the new devotees, regarding the vagaries and pros and cons of Clamshel *versus* Parallel.
Good Luck. Thank You… Mick. … .
P.S. from a quick glance back. excellent working schematic diagram, if you were to freeze frame metaphorically! a few degrees out from the final approach, onto impression? and then, metaphorically, introduce the variable impression adjuster, between the rocking platen and the con rod, your schematic, would be a perfect facsimile of the real deal.

the clamshell is faster in action therefore there are more of them , the parallel is clean and precise at the cost of overall running speed ,therefore there are less of those around ,also explains why none were built in the more recent past . modern parallel has been left to the world of the Bobst etc ,very good machines but huge and extremely heavy not really for the folks here !!

Yeah, speed is the drawback of this style of platen. The only US company making them, Thomson-National, abandoned inking systems in the ’50s, but Gietz in Switzerland continued inking systems until perhaps the ’70s (and some spare parts were avaiilable into the ’90s). The smaller, lighter versions like the German Kobold and UK Vicobold are relatively fast, but get to A3 and they are way slower than any equivalent Gordon platen. And again, all US makers of Gordons had come up with feeders, unlike T-N.
If you had a bank of these presses in different sizes so you could suit the press to the job, that would be great. I just have a 15 x 21 Victoria, Even in the best conditions it does half the impressions per hour of my previous C&P (which was a very good specimen with long fountain, brake and variable speed motor), and doing short-run multicolor work makes it obvious why the Heidelberg platen became a favorite with both pressmen and the accountant, But this Victoria will do difficult forms the C&P couldn’t do, and is actually easier to feed even with problem stock, thanks to that slow platen motion.

It’s stronger than the C&P as well, no?

And that style of platen used an ink drum instead of an inking disc, which is more efficient or at least more purposeful to the distribution of ink (imho)

Nice. Would you please describe the technique and tools you used to create these animations. Can those be done in 3D space? I’ve seen some very impressive similar animations for Steam equipment. In fact my fondness for steam machinery, with all the linkages and whatnot, was the reason I fell for my OS C&P and dove head first into Letterpress. They are superb machines. Good job

Hello: amazing animated links!
Hurrah for the C&P which is great either you have a hand press or a motor driven one.

For me the best is still the “Liberty” which is like the operation of the German made Hohner or the faster Heidelberg Windmill.

Thanks Oprion!

I fiddled with a cutaway of the Heidelberg platen last summer. While this test image is flawed, it at least shows the basic idea:

These are all extremely good in the showing of the way the pressure applies to the type ,it will certainly educate the newer devotees in the aspect of platen levelling.

AnonyMouse: I love the cut-away animation!

Mister Zag: my process was rather low-tech. The presses were drawn in Adobe Illustrtator, animated by hand (frame by frame) then exported as layers into Photoshop and combined into animated gifs. I am sure there’s a better (and easier) way of doing this. Perhaps something like SolidWorks would do the trick.

Likewise, Oprion. :-)

The cutaway was lifted from Heidelberg’s tips book and traced in Inkscape. Then parts were modeled in CAD to constrain the linkages. Then frames were output as DXF and combined into .gif files in GIMP. (Too painstaking. Next time I may use Blender.)

Another press in action:

“Carola” lever press by Kamenzer Maschinenfabrik

It’s almost like a desktop version of the good ol’ “Liberty”!

Ivan -

These are charming; a joy to see. I operated all of these presses for years before I realized that the Kelseys. Victors, Gordon, Pearls, C&Ps and my Colt & Heidelbergs all used different mechanisms to make contact between the platen and the form.

It actually came to me one evening as I was sitting in my shop, just looking around at the presses, when all of a sudden, it came to me just how different they all were.

For years, I had simply set the rollers, leveled the platens, mounted the tympans and printed without seeing the amazing variety of mechanisms used to make a print.

Your animated gifs are indeed unique and valuable works of both art and engineering.

Thank you.
- Alan Runfeldt