Choosing the right hydraulic cylinder for your equipment can be a challenging task. It’s essential to ensure that your purchase is compatible with your equipment and helps you achieve your goals. The first step is to identify the type of hydraulic cylinder you need: welded rod, integrated valve, telescopic, or another design.
Automotive Lift Repair Tampa Florida Telescopic cylinders offer an extended reach while remaining compact when retracted. Also known as telescoping or multi-stage cylinders, these are ideal for heavy-duty equipment with limited space. There are three primary designs for telescopic cylinders: single-acting, double-acting, and combination single and double-acting.
Common Uses for Automotive Lift Repair Tampa Florida Telescopic Cylinders
They are commonly used in platform lifts, dump hoists, dump lifts, and pack/eject functions. If your application requires linear force over a long distance, telescopic hydraulic cylinders are an excellent option for various types of equipment, including:
– Dump trucks
– Garbage trucks
– Transfer trailers
– Construction machinery
– Agricultural equipment
– Industrial mobile vehicles
Types of Telescopic Hydraulic Cylinders
While each type shares numerous advantages and applications, it’s crucial to understand the differences among them.
Automotive Lift Repair Tampa Florida Single-Acting Telescopic Cylinders
Single-acting telescopic cylinders feature a simple design that uses hydraulic pressure for extension and relies on gravity or another external force for retraction. They typically have a larger outer diameter than rod cylinders and deliver dependable, long-lasting performance. Common applications include dump trucks and platform truck/trailers.
Double-Acting Telescopic Cylinders
Automotive Lift Repair Tampa Florida Double-acting telescopic cylinders utilize hydraulic pressure for both extension and retraction. They are ideal for situations where gravity cannot assist in moving loads, such as with horizontally mounted cylinders. These cylinders are often employed in non-critical positioning applications, refuse vehicles, and transfer trailers.
Combination Telescopic Hydraulic Cylinders
As their name suggests, combination telescopic cylinders feature plunger rods that can function as either single or double-acting, using hydraulic pressure for part of the stroke while retracting through gravity or external force. These multi-stage telescopic cylinders are commonly found in large mobile drilling rigs and other heavy-duty applications.
The primary advantage of telescopic cylinders compared to other types is their capability to provide an exceptionally long stroke while maintaining a compact initial size. Typically, the collapsed length of telescopic cylinders ranges from 20% to 40% of their extended length, making them an ideal solution when mounting space is restricted and a long stroke is necessary.
For instance, consider a scenario where a dump body must be tilted to 60° to fully empty it. If a conventional Automotive Lift Repair Tampa Florida rod-type cylinder—featuring a one-piece barrel and a long enough stroke to achieve this angle—were used, the dump body wouldn’t be able to return to a horizontal position for highway travel, even when the cylinder is fully retracted. A telescopic cylinder easily resolves this issue.
While telescopic hydraulic cylinders are relatively simple devices, their effective application requires an understanding of their unique characteristics. Familiarity with how these cylinders operate and what specific criteria to consider will allow for their safe and cost-effective integration into equipment.
Structure and Operation
Automotive Lift Repair Tampa Florida Telescopic cylinders are designed similarly to a telescope, consisting of sections of steel tubing with progressively smaller diameters nested inside one another. The largest diameter section is referred to as the main or barrel, while the smaller moving sections are called stages, with the smallest stage also known as the plunger. Typically, the maximum practical number of moving stages is six; although theoretically more stages could be designed, stability would become a significant concern.
Thus, the largest stage moves first and completes its stroke before the next stage begins to move. This sequence continues until the smallest stage is fully extended. Conversely, during retraction, the smallest stage fully retracts before the next stage begins to move, continuing until all stages are nested back into the main barrel.
Basic Types
Like conventional cylinders, telescopic hydraulic cylinders are categorized into two basic types: single-acting and double-acting.
– Single-Acting Telescopic Cylinders: These extend under hydraulic pressure and rely on gravity or an external mechanical force for retraction. They are often employed in applications where a load is consistently present on the cylinders, such as in dump trucks and dump trailers. In these cases, pressurized oil extends the cylinder to raise one end of the dump body, and when pressure is released, the weight of the dump body forces oil out, causing retraction.
– Double-Acting Telescopic Cylinders: These are powered hydraulically in both directions and can be used in applications where neither gravity nor an external force can assist in retraction. They are well-suited for non-critical positioning applications that require both extension and retraction movements with significant loads.
Bearings and Seals
Each stage of a telescopic cylinder is supported by at least two bearings, with one located at the next larger stage. The distance between these bearings determines how much one stage overlaps the next, which generally must increase as the overall stroke lengthens to resist deflection from the weight of extended stages and the load.
There are various designs for sealing telescopic cylinders. A common design features multiple hinged chevron V seals or one-piece, multi-lip seals with molded-in hinged lips. These seals are secured in place by a stop ring or snap ring and a packing nut, utilizing guide bearings on the sleeve piston. Each stage’s internal diameter is sealed against the outer diameter of the next smaller stage.
The style and placement of these seals vary among manufacturers and depend on their specific functions. Zero-leakage, multi-lip soft seals are typically located in the internal diameter at the packing section of the main and moving stages, while low-leakage hard seals are found on the piston end of double-acting telescopic cylinders, allowing for retraction under pressure. Some single-acting telescopic cylinders use soft, zero-leakage seals on the piston, which utilize the full bore of the next larger stage for effective extension force, while also containing the oil within the cylinder.
In this design, the upper end of the Automotive Lift Repair Tampa Florida cylinder typically contains a bearing for guidance, and if any seal is present, it is usually a wiper/seal combination designed to prevent contaminants from entering the cylinder. Regardless of the type, the numerous sealing surfaces must accommodate normal deflection of stages as the cylinder extends.