They are separated except at the front, where there are two openings.
At the end of travel of the key, the bits on the end of the key pop up from the lower to upper chamber, compressing the two springs.
82) Enough Roman iron barbed spring padlocks and keys have survived to give us a good idea of their design and function.
If the neck were just a bit narrower, it could slide down the slot and compress the (missing) springs.
5034 This little iron padlock is a smaller version of 4899.
In this case the locking piece is close fitting and has no shield. Assembly of this lock is by forging, riveting and brazing. Only patches of gilding remain, but it must have been quite decorative. The bottom of the case is slightly decorated with four file cuts at each end. Because of that design, we can even tell what the key and the locking assembly must have looked like.
I note that there is a substantial groove worn in the shackle where it would have been in contact with the locking piece when closed, indicating that the lock was used for a long time. 5265 You have to wonder why this tiny iron padlock was made! Seems to me that a bronze one would have been more attractive, even at that time. A lock this size could be broken rather easily anyway. Perhaps, I don't know what the economics of producing locks of different materials would be. The key is so simple that it would probably not be recognized by excavators as a key, and we are not ever likely to see one!
There is another type which I do not have, and which does not quite fit into any of these categories: the rectangular iron padlock with riveted case.
The example shown at left is from Fishbourne (Cunliffe, pl.
Shown here are some examples found in Britain (Ward, 1911) Small bronze barrel padlocks (2" or less) with barbed spring mechanisms that I have seen, sometimes ascribed to Roman times, are medieval.
Three iron barbed spring padlocks (4899,5034,5073) are shown here that have an unusual configuration that I have not seen described previously.
A sketch of a somewhat later two-chamber Swedish lock is shown at right (Historicallocks.com/Vendel-Era) 4865 Large iron padlock with attached chain.
Also quite similar to 4899, except there is a conventional keyhole at the end for a slide key. The spring assembly enters high on the end of the case, which has a hooded extension.
The keyhole is on the side of the case, requiring a curved slide key.