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P-38 Patent Info



Get Can Opener - the only can opener you will ever need a P-38 folding can opener.


Patent Chronology

US Patents
D. 168,053     La Forte

1913 - 1,082,800    Darque'
1922 - 1,404,880    Montes
1924 - 1,507,093    Schioniger
1928 - 1,669,311    Strengberg
1941 - 2,251,200    Pohle
1941 - 2,257,532    Perocco
1945 - 2,375,274    Bloomfield
1945 - 2,391,732    Mirando
1946 - 2,412,946    Bloomfield
1946 - 2,413,528    Speaker
1951 - 2,546,257    Eckman
1956 - 2,733,505    Kenington
1981 - 4,300,288    Klyakharov
1993 - 5,189,750    Brennan

Foreign Patents

1937 - 817711      France
1937 - 820407      France
1945 - 908801      France
1951 - 802610      F.R.Germany

We are ALWAYS seeking more patent information that is related to the p-38 or p-38 style can openers - if you have any information you wish to contribute please contact us direct.



We want to extend thanks to Bob Shaver and his Patent Pending Blog web site for contributing to the P-38.net project. 

Mr. Shaver has become a trusted and valuted friend and contribution.

Thank you Mr. Shaver.


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P-38 Patent Information

There is evidence that the P-38 Can Opener was invented much earlier than had previously been thought.

In an informative blog by Mr. Bob Shaver, he illustrates that the P-38 can opener or similar can openers were patented as early as 1913 . . .

April 22, 2005

Can Openers Again

This appears to be the WWII era patent for the P-38 can opener.  However, it appears that there were a series of earlier patents for can openers that were pretty darn similar, if not identical.  The earliest seems to be from 1913. 

One question that pops to mind, is how could the latter of these patents have been allowed? 

My guess is that 1) maybe the examiner for the latter patents didn't know about the existence of the earlier ones, or 2) each of the the latter ones have slight changes to the design, and the claims include the changes. 

The changes don't have to be improvements, they just have to be different than the earlier design, and not obvious. 

Thanks to my buddy Eric for the in-depth search.

Bob Shaver

This excerpt from Bob Shaver's P-38 Blog #2.

- Patent Pending Blog Web Site-
- P-38 Can Opener Blog #1 -
- P-38 Can Opener Blog #2 -
- P-38 Can Opener Blog #3 -
- DogTagsRus Blog -
- Introduce Your Kids to Entrepreneurship Blog -

- Bob Shaver Website -

Patent 1913

This is an interesting can opener, it is much like the current P-38 can opener but it is more rectangular and there is no strengthening rib down the back of the body.  The rim catch is also more rounded than the current P-38 can opener.

The P-38 GI Can Opener

In the early days of WWII, the Army designed C rations.  What they needed to go along with the canned food of C rations was a very small disposable can-opener.  Designed in 30 days by the Subsistence Research Laboratory of Chicago, the tiny folding can opener was perfect.  As the troops used it in field conditions, it was realized that it was the perfect invention.  It was tiny, almost weightless, and it did the job.  Experience proved that 38 punches of the can opener would open a C ration can, and it became the P-38.  It also was perfect as an emergency screwdriver, as a cleaner for boots and a million other tasks.

This excerpt from Bob Shaver's P-38 Blog #1

Patent 1928

This can opener appears to be very similar to the P-38 but there is no hole in the body and by the drawing it appears the body is very narrow and longer than the P38.

Patent 1933

I have never seen an example of this specimen but it appears to be another attempt at perfecting the can opener.  If anyone has an example of this can opener we would love to have a photograph for our archive.

Blog response to Bob Shaver's original P-38 Blog.

I still have the first one I grabbed out of our first box of C-rations, in Army boot camp in 1977. The only place a GI could get them was in a case (12) of C-rations, where they appeared to be thrown in as an afterthought, 4-5 to the case. It's on my keychain. I still use it to open cans when camping (car-camping, that is). I've used it to adjust my carburetor, get a grip on a splinter, clean my fingernails, pick my teeth, adjust rifle sights, let air out of a tire, rip open taped boxes, and open cans of all sizes to the gasps and amazement of lookers-on. It shows no sign of wear, other than the hole where the keyring has carried it for 28 years.

Posted by Lucky - May 2, 2005

Patent 1945

One thing about this patent that is missing from the current military engineering drawings is the little stop "boss" that keeps the blade in the closed position until it is purposely opened for use.

Patent 1946

J.W. Speaker Company did in fact make these can openers.  It is hard to see all aspects of this drawings as there is NOT a break out of the blade itself but none-the-less this is a wonderful drawing.


We want to extend big Texas thank you to Mr. Shaver and his on-going effort to research the history of the folding can opener.  Using his blog as his soapbox he has enlightened and informed all of us.  Since his first posting of patents that involve the P-38 can openers he has revisited the subject with new and interesting information.

Patent 1923

This can opener is extremely interesting as it has a folding clasp that holds the cutting blade in the closed position when not in use.  This unit also has a build in bottle opener.  One wonders if the folding clasp was chamfered on the end would it also double as a screwdriver?

Patent 1953

Another P-38 derivative - it folds flat into a recessed pocket that is formed when the main body of the can opener is stamped then folded over.  The cutting blade swings outward from the recessed pocket for use by the operator.

This can opener is interesting as it has two cutting blades.  It has qualities of the P-38 in that it folds flat when not in use and appears to have a formed rib for strength.

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