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Hydraulic Tie Rod Type Cylinders

Hydraulic Tie Rod Type Cylinders
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Double-Ended Hydraulic Cylinders

Double-Ended Hydraulic Cylinders
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Mill Duty Type Cylinders

Mill Duty Type Cylinders
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AHP STD Series-007

Hydraulic Telescopic Cylinders

Single Acting / Double Acting 2, 3, 4 Stages
 
Hydraulic Telescopic Cylinders

Introduction :
Telescopic cylinders are a special type of cylinder which can provide an exceptionally long output travel from a very compact retracted length. The collapsed length of a telescopic cylinder is smaller compared to the fully extended length depending on the number of stages

Telescopic cylinders are having such design so that they are subjected to large side forces especially at full extension.

These cylinders are available in single Acting & double acting type.

Application
• Automobile
• Scissor Lifts
• Earth Moving Equipment
• Material Handling equipment

Telescopic cylinders are specially designed hydraulic cylinders that provide an exceptionally long output travel from a very compact retracted length. Typically, the collapsed length of a telescopic cylinder is 20% to 40% of the fully extended length depending on the number of stages.

• This feature is very special for machine design engineers when a conventional single-stage rod-style actuator does not fit in an application to produce the required output stroke.

• Telescopic cylinders are usually powered by hydraulics, but some
special light duty designs are powered by compressed air.

 
• Telescopic cylinders are referred to as single-stage telescopic cylinders and multi-stage telescopic cylinders. A common application for telescopic cylinders on a construction site is that of the dumping on a dump truck. In order to empty the load of gravel completely, the dump body must be raised to an angle of about 60º. To accomplish this long travel with a conventional hydraulic cylinder is very difficult considering that the collapsed length of a single-stage rod cylinder is approximately 110% of its output stroke.
 
• It would be very challenging for the design engineer to fit the single - stage cylinder into the chassis of the dump truck with the dump body in the horizontal rest position. This task is easily accomplished, however, using a telescopic style multi-stage cylinder.
 
 

Air Bleeds
The option of bleed screws, illustrated below, is available at either or both ends of the cylinder, at any position except in the port face. The selected positions should be shown in the order code.

Stroke Limiters
Where absolute precision in stroke length is required, a screwed adjustable stop can be supplied at the cap end. Several types are available - the illustration shows a design suitable for infrequent
adjustment of an uncushioned cylinder. Please contact the factory, specifying details of the application and the adjustment required.

Rod Locking Device
These units provide positive locking of the piston rod. They require hydraulic pressure to release, while loss of pressure causes the clamp to operate, allowing them to be used as a failsafe
device. Please consult the factory for further information.

Single Acting Cylinders
Standard AHP series cylinders are of the double acting type. They are also suitable for use as single acting cylinder, where the load or other external force is used to return the piston after the
pressure stroke. Cast iron piston rings should not be used with single acting cylinder.

Spring-Return, Single Acting Cylinders
Series AHP single acting cylinders can be supplied with an internal spring to return the piston after the pressure stroke.
Please supply details of load conditions and friction factors, and advise whether the spring is required to extend or return the piston rod.
On spring-return cylinders, it is recommended that tie rod extensions be specified on the cylinder end in which the spring is located to allow the spring to be 'backed-off' until compression is
relieved.
Tie rod nuts should be welded to the tie rods at the opposite end of the cylinder, to further assure safe disassembly. Please consult the factory when ordering spring-return cylinders.

Multiple Stroke Positioning
To obtain linear force in one plane with controlled stopping at intermediate points, several designs are available. For three stopped positions, it is a common practice to mount two standard
single rod Style H cylinders back-to-back, or to use through-tie rods. By extending or retracting the stroke of each cylinder independently, it is possible to achieve three positions at the piston
end. An alternative technique is to use a tandem cylinder with an independent piston rod in the cap section. Please consult the factory for further details.

Rod End Bellows
Unprotected piston rod surfaces which are exposed to contaminants with air hardening properties should be protected by rod end bellows. Longer rod extension are required to accommodate the collapsed length of the bellows. Please consult the factory for further information.

Metallic Rod Wipers
Metallic rod wipers replace the standard wiper seal, and are recommended where dust, ice or splashing might damage the wiper seal material. Metallic rod wipers do not affect cylinder dimensions.

Position Switches
These can be fitted to give reliable end of stroke signals.

Position Feedback
Linear position transducers of various types are available for AHP series cylinders. Please consult the factory for further details.