The following notes, which should be consulted with the patent drawings, describe the way we believe Turner's lock would be put together.
- Screw drill pin (Fig.2) onto backplate.
- Lay bolt (Fig.3) onto backplate so that its two outside notches fit into two guide stumps on the plate.
- Insert the moving peg (Fig.4) into the gap at the top end of the bolt and secure it in place using the displayed pin (above the letter '6') – its round end fits in the hole on the top plate when locked.
- Next, the moving cup or rimmed wheel (Figure 5) fits on the bolt – over the drill pin. It admits an 1/8th inch high bolt stump through a slide hole on its base.
- The fixed rim (Fig.6) is then fitted inside the moving cup or rimmed wheel.
- Next the tumblers or spring bolts (Fig.7), of which there may be up to four or more in number, are fitted inside the fixed rim which has grooves to receive them. It also has slots on its side, similar to those on the moving cup, to admit the projecting heads and tails of the tumblers.
- The bridges or bridge wards (Fig.8) piece is then placed on top. Finally the cap is positioned over the moving cup and screwed to the fixed rim beneath; its base is also screwed to the backplate to hold it firm.
Secondly, the mechanism appears to work as follows:
The key (Fig.1) has up to two slits along its bit end enabling it to pass through the bridge wards. When turned three quarters round, the key bit steps bear against the tumblers or spring bolts, and depress their springs. This causes the tumbler heads to move out of their restraining side slots, which frees the moving cup. On its base is a stump (see Fig.5, next to the drill pin hole), and when the key is turned further its bit bears against this stump and turns the moving cup. The sides of the slide hole in the moving cup's base press against the bolt stump and move the bolt sideways.
The bolt is then brought down with the moving peg flush to the bottom of the top plate to open the lock. To place the bolt and peg in a locked position the key is turned in reverse.
Comment: this is a most unusual idea for a lock, and I have never heard that it actually exists. However if anyone knows otherwise information will be gratefully appreciated. The style of this illustrated lock looks to be that used on desks, cabinets or chests.
I suppose Turner had to introduce bridges or bridge wards as people at the time felt comfortable that they were there (much in the same way Barron maintained a ward system along with his tumblers). However the ward disc as shown does not appear to provide much by way of protection. The tumblers or spring bolts seem to have the appearance of disc tumblers introduced many years later. This "Thomas Turner" incidentally, is not so far as is known related to the Wolverhampton Thomas Turner who appeared on the scene around the 1840s.