I just bought an original copy of the British Patent Office publication relating to Dickson & Murray's Patent No. 873 of 1882 entitled "Improvements in Self-cocking or 'Hammerless' Firearms", and which I thought might interest readers of this forum.
Text of patent application Patent drawings << Broken link fixedDickson, gunmaker of Edinburgh, made a handful (27?) of 3-barrelled shotguns according to this patent. You've probably seen photos, but there's another one at:
http://www.theshootingsociety.com/blog.html?start=10Now, bear with me over the next couple of paragraphs. The text of a patent specification is generally divided into three sections: the Abstract which is a very short outline of the invention; the main Specification which describes the invention in detail; and a set of numbered paragraphs called the Claims which, if push comes to shove (not sure what the US equivalent of that phrase is! ("if the ordure hits the air conditioning"?)) are the definitive list of what is covered by the patent.
For a patent to be valid, its content must be novel (i.e. not publicised, patented, manufactured or otherwise in use before the date of the patent application) and the substance of the patent should not be 'obvious to someone skilled in the art'.
As someone who has worked on the administrative side of the patent system for 20 of the last 28 years, Dickson's first claim doesn't look to be on very solid ground to me. It reads "A three-barrelled gun or fowling piece of the type which in double and single barrelled guns or rifles is commonly known as "hammerless" that is to say guns having hammers or tumblers contained within the lock-casing substantially as hereinbefore described and shewn in the accompanying drawings".
Dickson might have been able to claim novelty for the detailed arrangement of his boxlock action, but neither hammerless guns nor three-barrelled guns (either with three barrels arranged in a row or in a triangular arrangement) were new in 1882. Looks like a classic case of 'claim everything and back off from claims you can't substantiate if challenged at a later date'!
Nigel.