[sumit patni]

Tower bolt / Barrel bolt

A door bolt which moves in a cylindrical casing; not driven by a key.



Latch

A simple fastening device having a latch bolt, but not a dead bolt; contains no provisions for locking with a key; usually openable from both sides.


Thumb Latch

Thumb latches are two-way latches and work as follows: on the outside (street-side) of the gate is a decorative plate with a thumb depressor. When you depress the thumb, a latch-arm on the inside of the gate lifts and allows the gate to be opened. Closing the gate, the latch-arm should hit the strike, rise up and fall into the catch on its own (a gravity latch).

Thumb latches can be installed only on in-swinging gates and are always double-sided. Some thumb latches are lockable, some are not.



Lift latch - for securing a door in a closed position, usually by means of a flat bar that falls into a catch when pressed by the thumb; for example, see Norfolk latch and Suffolk latch.

Suffolk latch - A type of thumb latch for doors; originally fabricated of iron wrought by hand in England. Attractive in appearance and available in many different designs; .=-

Norfolk latch - A type of thumb latch for a door that has a long metal plate behind the latch to protect the door finish; compare with Suffolk latch. .

Bolt Latch

some bolt latches might remind you of the old days, when you tied a string to a latch, tossed it over the gate, and called it good. Now there are a few spiffier versions of the old stand-by. We offer a nice selection of architectural bolt latches Usually bolt latches can be installed on either side of a gate. They are one way gate latches, operable only from the one side (although a string can get you access from the other side from the old style latch). Bolt latches are sometimes lockable, sometimes not. The lockable ones usually require an additional padlock.



Lever Latch

Lever latches operate in the same way as a ring latch, but instead of a ring on each side, there's a lever handle.
Lever latches can be installed on both in-swinging and out-swinging gates. On out-swinging gates, the latch-arm side will be on the street-side of the gate. The best way to remember is that the latch-arm of the gate latch must be installed on the side that the gate opens toward.
Lever latches can be either gravity-assisted or spring-loaded, depending on the manufacturer. Some lever latches are lockable; some are not.



Mortise Lock

A lock designed to be installed in a mortise rather than on a door's surface.