Most people turn door handles every day and never even give a second thought to the parts of a door handle until they need or choose to replace part or all of the handle. If you're going to DIY your door hardware, it can be useful to know more about door handle components first. The parts of a door handle include knobs/levers, latch mechanisms, strike plates, boxes and cylinder locks.

The most obviously noticeable part of the door handle is the knob or lever that actually allows the door to open. Knobs are generally round, although they may come in other shapes, and they open the door by turning, whereas levers (also called lever handles) open the door by pushing down. While it's pretty hard to install a door handle in the wrong direction, it's important to pay attention to the direction of a lever when installing one.

While not the most important of door knob parts, a rosette is the plate behind the door handle or lever. While the rosettes in most homes are simple metal pieces, they can be elegantly detailed, and some door handles, particularly those with vintage designs, don't have a rosette at all.

The Latch Mechanism

Perhaps the most important of all door handle parts is the latch mechanism. This is the spring-loaded piece that protrudes past the door, keeping the door closed. While most latch mechanisms use a retracting tubular latch mechanism that goes in when the handle is turned, some doors, like closets, use a ball latch. A ball latch doesn't retract when the handle is turned but instead is simply pushed open or closed in order to catch it on the specially indented strike plate.

The latch itself is generally fitted to the door with a mortise plate, which provides additional security and makes installation more easy so the latch is properly situated in the door in order to catch on the door frame when the door is closed. Additionally, the mortise plate makes the latch mechanism look much more attractive than simply having a floating latch stick out the side of the door.

When the door is pushed closed, the strike plate is the metal piece that the latch is pushed into on the door jam. The box is the hole where the latch fits in, which may or may not be fitted with a strike plate.

Ball latches require a special, shallow strike plate, but most retracting tubular latches don't require a strike plate because they will still retract and go into the box when pushed against a door frame. That being said, strike plates make the door function more smoothly, look more attractive and protect the door frame from damage caused by repeatedly being pressed on by the latch.

Push Pull Door Handle

The initial idea of push-pull door-handle is to ease opening of the door simply by mounting the push-pull door-handle, without any interference with the door, lock or doorjamb. installation is simple, the same as classic handle.
classical opening of the door takes place by pressing the handle and then either pulling or pushing the door away. push-pull door-handle does not require vertical pressure on the handle, since it is replaced by the movement of handle in the direction of opening the door, thereby opening is much smoother and more comfortable.
the procedure is the same, when we are closing the door. handle is pulled or pushed in the direction of movement of the door, so the door closes.
this is particulary usefull, when our hands are not free (if we are carrying different objects, pushing wheelchair or bed, or we are limited by disability). it is already sufficient that we lean with the body to the handle and push the door.
it would also be possible to use this concept on fire doors, where push-pull door-handle could replace special hardware, that lets you push-open the door.
it is also important that push-pull door-handle preserves function of the classic handle whit a vertical movement.

structure, function: