Helpful Hints - Peninsular Configurator

Model LH  NFPA Low Pressure Hydraulic Cylinders

" Spring Extend  /J"    and    "Spring Return  /K "

These optional features are NOT CONFIGURABLE within this configurator.  

Please contact Peninsular at at (800) 526-7968 in the USA or Canada or at (586) 775-7211 (you may also e-mail us at sales@peninsularcylinders.com  if you want this feature installed in our Model LH low pressure cylinders.

The spring return/extend optional feature is a popular cylinder option usually employed in single acting (hydraulic fluid powered at one cylinder end only) low pressure hydraulic cylinders. There are many reasons for the use of a spring extended or retracted cylinder, however, one common reason is for safety purposes that could protect human life in the event of an electrical power outage and resulting loss of hydraulic pressure. The spring in this instance assures the extension or retraction of the piston rod without the use of hydraulic power. Generally speaking, this technology is applicable to low pressure hydraulic cylinders up to and including 4” in bore size and with stroke lengths not exceeding 12”.

When selecting a spring extend or retract cylinder for your application you should make sure that all of your design calculations are correct and that your application requirements are fully understood. Also know that, although we never fully collapse the spring, that all springs can eventually fatigue and break, therefore, routine inspection of the spring, at the end user level,  is important and is recommended. Some important issues (but not all) to consider are as follows:

 

  1. What is the weight (load) that is to be moved ?  What is the bore size of the cylinder and the piston rod diameter of the cylinder ?

  1. Is the load moving in a vertical or horizontal direction ?

  1. Is the stroke travel unsupported or is it guided or supported in any way ?

  1. Is the load being moved in only one direction or is it being moved in both directions of the cylinder stroke? If in only one direction, is it on the push (extended stroke) or the pull (retracted stroke) of the cylinder ?

  1. What is the hydraulic line pressure that is driving the cylinder? Are there pressure drops that occur in the system ?

  1. What is the cycle rate of the cylinder ?

  2. What is the cylinder mounting style ?

Please discuss these and other issues with our engineering staff so that we can properly engineer your spring return/extend cylinder.

Peninsular cylinder company will not be held responsible for any failure applicable to spring return or retract cylinders because we can never know all of  the application complexities present where the cylinder is to be used.

One should also know that the overall length of the cylinder will grow to the extent of the compressed spring length and that this length can vary based upon the spring coil thickness selected, and the answers to the above questions along with other questions which could arise. Once the spring return/extend feature is employed, the cylinder no longer conforms to standard NFPA dimensions because of the increased cylinder length.
 

 

Spring Return  Model LH Low Pressure Hydraulic Cylinder

The Hydraulic Fluid is usually introduced through the Rear End Cap Supply Port.

 The Front End Cap Supply Port is then used for Hydraulic Fluid Exhaust.

 

Spring Return Hydraulic Cylinder shown in the Retracted Stroke Position

WITH NO HYDRAULIC PRESSURE  introduced through the Rear End Cap Supply Port

 

Spring Return Hydraulic Cylinder shown in the Extended Stroke Position

WITH HYDRAULIC PRESSURE introduced through the Rear End Cap Supply Port,

 Thus overriding the Spring

 

Spring Extend  Model LH Low Pressure Hydraulic Cylinder

The Hydraulic Fluid is usually introduced through the Front End Cap Supply Port.

 The Rear End Cap Supply Port is then used for Hydraulic Fluid Exhaust.

 

 

Spring Extend Hydraulic Cylinder shown in the Extended Stroke Position

WITH NO HYDRAULIC PRESSURE  introduced through the Front End Cap Supply Port

 

 

Spring Extend Hydraulic Cylinder shown in the Retracted Stroke Position

WITH HYDRAULIC PRESSURE introduced through the Front End Cap Supply Port,

 Thus overriding the Spring

 

Toll Free: 800-526-7968   Phone: (586) 775-7211   Fax: (586) 775-4545
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