Strong Cobb

Submitted by Susan Miller on Thu, 04/06/2006 - 11:52.


Does anyone know the history of the "Strong-Cobb" hardness test for pills? Wouldn't it be interesting if that bit of medical/pharmacological engineering took place on the Central Viaduct?

Strong Cobb Bottle.jpg58.97 KB
StrongCobbPostcard.JPG19.25 KB
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Here's a post card inside Strong Cobb


A high speed method for manufacturing tablets in quantities

Strong-Cobb & Company 


I came across this postcard in my browsing - Here they are showcasing their innovation in pill manufacturing - certainly to the Strong-Cobb pill hardness standard they developed (a method of testing breaking point) - looks like this was take on one of the middle floors and you can see the Lorain Superior Bridge out the windows - I found some other info on the  Strong-Cobb test and will post that ASAP

Cleveland's past... ad hoc units of force

Strong Cobb Arner Single Station Tablet Hardness Tester, Model M-19
Item #: 250003

1 Used Strong Cobb Arner Single Station Tablet Hardness Tester, Model M-19. This is a table-top tablet hardness tester complete with pressure gauge and automatic (electronic) compression punch. Unit is constructed of Stainless Steel, has a pivoting safety guard around punch and has 110 volts, single phase electrics. Was last used in a large pharmaceutical facility and is available for immediate delivery.



From a patent search site:

Device for measuring tablet breaking force

 United States Patent 4409843

There is provided a device for measuring the force required to break a tablet, wherein the device comprises a tablet holding means comprising a base, a tablet splitting edge in the base and an area for holding a tablet in an inclined cantilevered position such that at least a portion of the cantilevered segment of the tablet extends over the tablet splitting edge. Means are provided for exerting a force substantially normal to a portion of the cantilevered segment of the tablet extending over the splitting edge to thereby create a moment of force about the tablet splitting edge sufficient to break the tablet. The device includes means for measuring the force required to break the tablet.




From Dissolution 

Definition from: How Many? A Dictionary of Units of Measurement
© rowlett [at] email [dot] unc [dot] edu and the University of North Carolina at Chapel Hill

Strong-Cobb Unit (SC)
an ad hoc unit of force previously used to measure the hardness of tablets in the pharmaceutical industry. The Strong-Cobb test machine applied pressure using a hand-operated air pump, and the hardness was read on a gauge marked in 30 arbitrary units called Strong-Cobb units. It is generally believed that 1.4 Strong-Cobb units represented roughly 1 kilogram of force, so each Strong-Cobb unit represented roughly 0.7 kilogram of force or about 7 newtons.

Some Information on Tablet Hardness Testing

This article gives some background information on tablet hardness testing, it’s history, the methods used and points to look out for when comparing specifications.

History 1,2

The first tablet hardness tester was introduced around the mid-1930s. This was a purely mechanical device and is still manufactured today. Force was applied with a screw thread and spring until the tablet fractured and the hardness was read from a sliding scale graduated in ½ kg increments. This was followed by the so-called Strong-Cobb tester, introduced around 1950. The testing force was generated by a manually operated air pump and the tablet breaking force was measured on a dial graduated in 30 arbitrary units which were designated as Strong-Cobbs. The results given by the Strong-Cobb tester were not consistent with those of the earlier tester.

Electro-mechanical tablet hardness testing machines were later introduced and have evolved into electronic test instruments such as those produced by Engineering Systems. These contain a motor drive system to generate the force and electronics to automate the test procedure, automatically detecting tablet fracture and displaying the force in a variety of units. Measurements can be printed and / or downloaded to a computer.


Cleveland Memory


Wow, this is fascinating.  Susan, your story prompted a man at the University of Washington to contact you via RealNEO.   We have become a new generation of story tellers.  If we don't orally repeat our history over and over and dig through the buried past to retell the story, it will be lost. 


Virtual history is not permanent (here is a flashback--the Billy Joel part might be painful for some).  We are going to have to start talking to our children and listening to our children.  They are the Givers.

dear roboprof

Good eye Laura!

Welcome to realneo roboprof!

Per your inquiry and your message "Strong Cobb Hardness Tester. My father invented it. I have lots of info including the original patent. He sold patent to Strong Cobb for "$1.00 and other valuable considerations"...

This research regards the history of a building our illustrious highway builders wish to tear down. We began to look into the history of the Broadway Mills Building and found that Strong Cobb had used the building and that the pill hardness test still is labeled today as the Strong Cobb Unit. I contacted the Dittrick Medical Museum at Case Western Reserve University, but they never responded. We would like to tell the story, hear the story as currently Cleveland is being hailed as a medical miracle with the Cleveland Clinic and University Hospitals vying for the power in the region. Merchandise Mart Properties Inc. will take $800 million from taxpayers over the next 20 years to build a medical mart and convention center because of the medical industry here. Biotech and medical breakthroughs are being held up as the saving grace of a shrinking rustbelt city. We want to also look back to past medical innovations and not erase but learn from and appreciate our history. Please, please tell this story in as much detail as you know here on realneo.

Did your father, did you live in Cleveland? please share what you know so that we might know more about our region's history, medical, phamaceutical, innovation and otherwise.

We are all to eager to forget here in NEO. Maybe it's the lead... We erased Millionaire's Row, forgot Charles Brush and Warner and Swasey and seem to want to forget Burnham and Brunner. Arghhhh! Let us not forget the origin of what became an international unit of hardness testing - the SCU.

This has nothing to do with

This has nothing to do with the subject at hand - but Tremont West wants to hear nothing about past history.  They want to move forward and leave the errors, mitakes, blunders and especially oops on their part.

My way of looking at things - if you don't know what made the bridge fall, how do you know what to nail back so that history doesn't repeat itself.  Understanding the problem is the first step in rectifying and/or improving anything.