A tubular latch is an item of ironmongery which is usually morticed* into a door, which allows the door to be opened and closed by means of a Door Handle or Door Knob. The word 'latching' is the act of a door being closed, and remaining held shut.
A tubular lock has its latch bolt and dead bolt in two separate holes. In a mortise lock, both bolts are encased in a steel box that fits in one hole.
Lever latch door handle on backplate
It consists of a handle/lever on a backplate which when pushed down turns the spindle which passes through the door and the tubular latch inside the door allowing the door to be opened.
The Backset is the distance from the faceplate of the latch, to the centre of the follower. The size of the Backset is important because it will determine where your handle or knob sits on the face of the door.
Cut the Latch
Using a chisel, cut along the outline as deep as the plate is thick. Then chisel to the same depth every 1/8 inch between the top and bottom of the plate outline. Turn the chisel bevel-side down and remove the waste, working from the middle out.
The backset is the distance from the edge of the door to the center of the 2-1/8-inch bore hole. In the United States, there are two common backsets for residential door locks: 2 3/8 inches and 2 3/4 inches.
Tubular locks are commonly found on all types of doors and are ideally suited for new (post-1950's) pre-drilled doors. Tubular locks have a spindle assembly that extends into or through the center of the latch, allowing for retraction of the latch bolt when the lever or knob is rotated.
A latch is a storage device that holds the data using the feedback lane. The latch stores 1 -bit until the device set to 1. The latch changes the stored data and constantly trials the inputs when the enable input set to 1.
As verbs the difference between lever and latch
is that lever is to move with a while latch is to close or lock as if with a latch or latch can be (obsolete) to smear; to anoint.
The latch-type handle is a type capable of closing a door by one touch and suitable for specially equipped vehicles, construction machines, buses, railway trains and vibration equipment.
A mortice latch is the bolt that holds the door in it's closed position and is operated by a spindle which passes through the door and is in turn operated by a pair of door knobs or handles. The latch contains the spring which enables the door knobs/handles to return to their original position.
A mortise is a hollow gap made on an object like a door or lock to fit in hardware. When created on a door, it enables the hinge to fit snugly. Moreover, to install the locks, you need to mortise a part of the door frame. At some point, you might need to mortise a door before it can close well.
As adjectives the difference between cylindrical and tubular
is that cylindrical is shaped like a cylinder while tubular is shaped like a tube.
A tubular latch is a simple spring-assisted mechanical device to keep a door closed without the use of a lock. It is mortice fitted into a door giving a flush finish rather than being surface mounted, and is the most commonly used latch in our homes.
Drive-In Latch
The drive in latch is the easiest to install. You don't have to chisel anything out of your door, just tap the latch into the hole (make sure the latch is placed in the correct direction) and you can install the knob or lever. If your door is already prepped for a larger faceplate, these won't work.
The distance between a deadbolt and door knob is usually 5 1/2 to 6 inches above the handle. Most do not recommend placing it any higher than 6 inches from the original knob unless the situation calls for it.
Passage door knobs are similar to dummy door knobs. They don't lock but are used to open doors and go between rooms. Passage door knobs are ideal for interior hallways, closets and other rooms that don't need privacy locks. They're also called unkeyed knobs.
The first thing you can try for opening a jammed latch is to slide a plastic card (e.g. a credit card) between the door and the frame where the latch is located. This will hopefully force back the latch and the door will open.