Construction:

Figure shows three Rams assembled in each other like telescope. This arrangement provides relatively long stroke with good mechanical strength. There are two inlet ports through which pressurized hydraulic oil enters. Port (R) is raising the cylinder or extending the cylinders while port (L) is for cylinder lowering.

Working:

1. Raising or extending the cylinders: hydraulic oil under pressure will enter through port (R). Space "X‟ will be filled by oil and Ram 1 will start raising upwards. When its raising stops, the oil now will start entering through and will occupy space "Y‟. Due to this Ram 2 will raise. When raising of Ram 2 stops, the oil will start entering through and will occupy space "Z‟. This will raise final Ram 3 upwards.

2. Lowering the rams: When pressurized oil will enter through port (L), then Ram 1 will come down. After it‟s lowering Ram 2 will lower and then Ram 3 will lower.