Hydraulic technology has ushered the minimum effort, maximum result concept in almost every other industrial activity. A ready example is excavation of earth for basement at the construction site of a building. In contrast to the manpower and man-hours spent in executing this task that would have prolonged for over ten days at a stretch, a hydraulically operated excavator does the same job in a single day. The key element in a hydraulic system is the cylinder, the mechanical actuator, aptly referred as hydraulic motor. There are two versions. Single acting hydraulic cylinders which are simple in design as well as economical and the double acting cylinders. While the single action cylinders function with fluid on only one side of the piston, the latter have a port at each end that are lubricated and supplied with hydraulic fluid for both the retraction and extension action. By and large, the single action cylinders are found in almost all the steam and petrol or diesel driven IC (internal combustion) engines and also steam turbines, pumps, presses and ramps. The following are the main parts of a cylinder and these are designed and manufactured with utmost precision in which specifications could be as minute as 4 to 16 of a microinch:
