# Stroke (mechanics)

In the past, only the vertical movement of an object from bottom to top was referred to as stroke - a derivative of to lift .

## Stroke by direction

• If it is the original, vertical stroke from bottom to top , it is called an upward stroke today .
• The reverse movement after an upward movement is called the downward stroke .

A continuously repeated upward and downward movement of an object is collectively referred to as a lift, see for example the tidal range . In the course of time it has become common to refer to all movements of an object from point A to point B in a straight line and regardless of the direction as a stroke.

## Stroke of cylinders, pistons and guides

The stroke of a piston (piston stroke) in a cylinder is also known colloquially as the cylinder stroke . The displacement of a cylinder (the cylinder displacement ) results from the multiplication of the stroke and the piston area.

### Stroke in linear technology

• If a linearly movable component is extended, it is referred to as a forward stroke .
• If a linearly movable component is retracted, it is called a return stroke .
• A double stroke means a complete sequence of forward and return strokes.

In linear technology , a stroke is understood to be the path that a linear guide covers, the stroke of an actuator or a linear drive , whereby these machine elements and assemblies can be installed in almost any position in space, i.e. the forward and return strokes can take place in any direction can.

In particular, electromechanical actuators are also referred to as electromechanical lifting cylinders , electromechanical cylinders or simply just as lifting cylinders.

### Stroke in piston engines

In piston engines , the path that the piston travels between top and bottom dead center is called the stroke or piston stroke . Since the cylinders can also be arranged horizontally or hanging (then the crankshaft is above the cylinders), horizontal movements between defined points are also referred to as stroke . In the dead center , the piston changes direction and cannot generate any torque. The volume in the cylinder is smallest in the top dead center and largest in the bottom. This also applies to hanging cylinders.