In some single-acting cylinders, the piston rod has no piston on the inner end. Instead, the end of the rod serves as the piston. This is called a ram-type cylinder.
... ram cylinders, consisting of a cylinder in which a piston is hydraulically or pneumatically set in motion so that the hydraulic or pneumatic energy acting on the piston is converted into a linear movement, are hydraulic or pneumatic engines and motors ...
