Unusual Early Rim Lock - Circular Patent

Brian Morland MLA Hon

An interesting but so far unexplained lock from the collection. It’s a 6″ rim deadlock, the only markings being a brass semi-circle plate attached to the inner cap with the wording ‘CIRCLAR PATENT’. The mechanism has one tumbler and one spring loaded revolving disc. The tumbler is unusual in that’s its double acting but with two attached bolt stumps that locate on each side of the bolt lath, unlike Barrons which had one stump locating in notches in the middle of the bolt. The disc is rotated, by the action of the key, which has a gating cut in it and engages another bolt stump fixed to the case. No reference so far has been found in the British patents to a ‘circular patent’ but the American patents have not yet been searched.

Needless to say if the lock were found worthy of further discussion I would be happy to post more pictures.

Paul Prescott

The use of the spring loaded disc may be significant. There was a family lock lockmakers, they are mentioned in Price that used such designs. I had a lock once and I know of a couple of others. I’ll post the name as soon as it comes to me ..

Paul Prescott

The maker I am thinking of is ‘Walton’ check Geo Price page 418. Perhaps some internal pictures would shed some further light ?

Brian Morland MLA Hon

The Walton’s is certainly a contender, although nothing George Price says in his ‘Treatise’ does in-fact describe this lock – but certainly it’s the kind of thing that could have been produced by that inventive family. Somerford’s first lock c1815 or Youngs Lock patented 1825 might describe the double acting tumbler here however Youngs description doesn’t describe the disc in the Circular patent lock.
I have attached 3 more images of the ‘Circular Patent’ lock.

The first shows the lock with the cap removed…

another with the bolt removed to show the double acting tumbler…

and finally the underside of the bolt with the attached rotating disc.

Its quite interesting when reading through the early inventions and patents to see how one idea might have sparked another. Certainly none of the British patents up to the Great Exhibition describe the lock or mention ‘Circular Patent’. A great deal was made of Barrons patent of 1778 at the time with ‘double acting tumblers’. One theory is that this lock was a demo as the brass plate is on the cap and would never be seen once fitted. There are also many examples of the Victorian lock makers describing their locks as patent where no patent has been found. It may also be the lock is not British but from an English speaking country such as America.

Paul Prescott

I would agree re the description. But the two Waltons locks I have seen (which where marked) were not as described in Price either. You comment that the lock could be US in origin may well be on track.

Richard Phillips

I’ve seen that sort of double-acting tumbler mentioned somewhere, probably PRICE. Similar in effect to Parsons’ Balance Lock, differently realised. Did Kaye of Leeds use something similar? but this lock looks much older.