Telescopic Hydraulic Cylinders

Application-Specific Designs
Telescopic hydraulic cylinders utilize multiple nested stages. These achieve a long working stroke in compact/retracted form. Aggressive Hydraulics engineers application-specific designs to ensure that you get the proper cylinder for your application.

Common Types of Telescopic Cylinders:

Single-acting cylinders
Double-acting cylinders
Combination of Single- and Double-acting

Features & Specifications

Single and Double Acting Telescopic Types
Common hydraulic pressures up to 2,000 psi, special applications optional up to 3,000 psi
Max bore size available up to 15″

Min stage size available down to 3/4″
Common stroke lengths up to 500″
Number of stages common up to 5

Resources

Telescopic Cylinder Worksheet

"Purpose-Built" Hydraulic Cylinders & Components Catalog

Single-Acting Telescopic Cylinders

Single-acting cylinders use hydraulic pressure to extend, and retract due to load from gravity or some other external force.
Hydraulic flow and pressure extends the cylinder
Gravity or some other external force will retract the cylinder
Holds position
Long stroke in a compact closed length
Larger outer diameter than rod cylinders
Less complex design than double acting

Double-Acting Telescopic Cylinders

Double-acting cylinders use hydraulic force for both extension and retraction.
Hydraulic power retracts cylinder as opposed to gravity/force
Retract force is able to pull load
Conventional telescopic cylinders
- Both ports located on rod end
- Piston seals are typically cast iron rings
- Cylinder is not designed to hold load in exact positions (drifting)
- Minimum flow required to prevent stalling
Special features can be designed into telescopic cylinders
- Both ports on the barrel design avoids moving hoses and wear patterns
- Positive piston seals allow cylinder to hold the load and eliminate the minimum flow requirement
- Less dead lengths per stage than a conventional double acting telescopic

Partially Double-Acting

Partially double-acting cylinders are typically used in over-center applications. These cylinders will provide retract force for a portion of the stroke, and gravity completes the retract cycle.

Plunger rod can be double acting and sleeves single acting.
Largest sleeve can be double acting and balance of sleeves and plunger rod single acting.
Skip-a-sleeve option, which is a sleeve or stage is skipped during design, thus increasing effective area and retract force.