Telescopic cylinders for hydraulics consist of several sleeves, or tubular rods, typically four to five. These are nested sleeves that diminish in size as they go to the center. Telescopic cylinders have advantages in lifting-power and reach.
How a Telescopic Cylinder Works
A telescopic hydraulic cylinder works by introducing pressure to the assembly. The outside, or largest sleeve, extends first. At its full extension, the next size down follows and all others sequentially to full extension of the assembly.
Types of Telescopic Cylinders
A telescopic hydraulic cylinder can come in two types, a single-acting assembly or a double-acting assembly. The most frequently-used is the single-acting version, which depends on outside forces, like gravity, to cause it to retract. After pressure release, this force expels the oil out, allowing the cylinder to retract.
Constructed for Heavy Lifting
Hydraulic cylinders are also the preferred application for heavy lifting over pneumatic cylinders. Telescopic hydraulic cylinders typically collapse at 20 to 40 percent of full-extension length, allowing them to operate from smaller spaces. The multi-sleeve construction also allows telescopic cylinders to extend further than single-stage designs.
Hydraulic Cylinder Features
Features that make welded telescopic cylinders ideal for heavy work include:
- Mounting-style choices
- Re-buildable assemblies
- Chrome plating for each stage
- Adjustable and high-quality Vee packing
Custom-Built Cylinders
Custom-built hydraulic cylinders are also possible, including double-acting cylinders, which are not as commonly stocked but do allow for greater control due to oil pressure on both sides of the rod’s piston.