Sometimes referred to as multi-stage cylinders, these are ideally a form of a linear actuator with tubular rods (sleeves) that can be 4-5 in number and sequentially reduce in radius and remain nested inside of one another.
Upon the introduction of hydraulic pressure into the cylinder, the first extension occurs at the largest sleeve known as the barrel or main.
Once the main achieves its maximum stroke, a stage or the sleeve that follows will start to extend. Apparently, the process of extension is repeated until the last stage, known as the plunger, is reached.
Telescopic hydraulic cylinders exist in two forms: single-acting and double-acting. The former is the most common and works using gravity or an external force to help in the retraction of the various stages.
Upon the release of pressure from the cylinder, the oil is pushed out by the force applied by the load, thereby allowing the cylinder to retract.
How are Telescopic Cylinders Used?
Despite hydraulic power being much more common, pneumatic telescopic cylinders still do exist. However, hydraulic power is much more reliable where one is required to move very heavy loads.
Telescopic hydraulic cylinders feature a collapsed length of about 20-40 percent of the typical or ideal length when fully extended.
Therefore, they are useful where the extension to lift heavy loads should be initiated from a very tight space or within limited spaces. As a result, a longer working stroke, thanks to the extension capability.
Such an extension capability may not be achieved using a single stage actuator. However, with the extension capability achieved using the multi-stage actuator and the ability to effectively handle a very heavy load, hydraulic telescopic cylinders have proven very effective in accomplishing heavy-duty pieces of work involving lifting within a very limited space. Its application includes lifts, garbage trucks, and dump trucks, which form part of our day-to-day activities.
Mobile applications tend to require cylinders with a small profile and yet deliver long strokes that can be used in lifting heavy loads over a given distance.
Therefore, using this technology seems to be the only logical solution where a dump truck’s body needs tilting to 60 degrees to allow the emptying of its contents.
If its body were to be fitted with a typical rod-type cylinder, involving a single-piece barrel and very long stroke to enable the body to reach 60 degrees, it would be impossible to return the body to its original horizontal position to suit highway travel, as the cylinder length would be disrupting electrical lines, wires, blocks, and other overhead objects even after full retraction.
The use of technology that allows full retraction while providing the power required to do the heavy lifting easily solves the problem and helps to create sanity on the roads.
Telescopic hydraulic cylinders allow the successful lifting of heavy objects and loads within a very limited space.
They are ideal for lifting in small spaces but over a long distance. Mobile applications of this technology include dump trucks, which contain barrels of different sizes and extend to achieve the intended objective.