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Catalogue Technical Specification

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Safety Features You Can Trust - Unique & Patented

Gas Spring

Safety Features     User Information     N² Benefits

CAD Viewer Technical Data
CAD Viewer Technical Data


Safety Features 


Our unique and patented safety features are designed to protect in four key areas - over pressure. over stroke, uncontrolled speed & contaminants. All of these represent a danger to personnel and will irreparably damage the cylinder. Our safety features therefore primarily protect against injury but are also cost saving.



SKUDO - Active Protection Against Contaminants

SKUDO is a cap made from plastic material, fixed to the end of the rod end following its movement and represents the utmost active protection of the cylinder against liquid and solid stamping contaminants. SKUDO is an international patented device. 


SKUDO is a protection device not subject to wear, that has no contact with moving parts and guarantees total protection of the rod and seal. It eliminates the risk of filling the internal chamber of the cylinders with stamping liquids preventing an uncontrolled increase of the pressure with possible structural collapse.

SKUDO is the most advanced protection against liquid and solid stamping contaminants available.

- Increases safety.

- Eliminates unforeseeable and early wear and deterioration of the guide and seal elements as well as damage on rod sliding surface.

- Offers a significant increase in service life, and is therefore money saving.

- Does not increase the price of the cylinders.

- Does not wear out or alter the height of the cylinder.

>1.000.000 strokes
and still working
Model: HR 2400-125AM
Quantity: 4 pcs
Working Stroke: 120mm
Stroke per minute: 27
strokes only!


SKUDO is installed in the following series: MSKERS, and the models fitted with it are clearly indicated on the PDF information. 

OPAS - Over Pressure Active Safety


This is a device installed directly on the bottom of the cylinder with the function of exhausting the gas pressure when it exceeds the default maximum value.

OPAS activates itself by breaking the safety valve then releasing the pressure inside the cylinder completely.

- Eliminates the risk of overpressure.

- Eliminates structural failure due to overpressure.

- Activates itself automatically regardless of user intervention.

- Does not increase the price of the cylinders.

OPAS is installed in the following series or parts of them: M, ML, KE, RV, RF, RS. The models fitted with it are clearly indicated on the PDF information. 


OSAS - Over Stroke Active Safety


This is a device designed to exhaust the pressure inside the cylinder when the real working stroke exceeds the maximum nominal value of the stroke.

It consists of a groove machined on the inner wall of the cylinder that creates a discontinuity at the contact surface of the outer sealing element of the bushing and allows the gas to vent in the occasion of an overstroke.

OSAS is activated by pushing the bushing downwards which brings the outer seal element on the discontinuity of the wall thus exhausting the pressure inside the cylinder.

OSAS is self activated so is activated before the pressing pad collapses against the cylinder body, preventing any structural damage to the cylinder and improving the users safety.

- Exhausts the pressure inside the cylinder when the working stroke exceeds the maximum nominal value of the stroke.

- Makes harmless a cylinder that has been subjected to an over-stroke action by exhausting the pressure.

- Activates itself automatically regardless of user intervention.

- Does not increase the price of the cylinders.

OSAS is installed in the following series or parts of them: M, ML, KE, RV, RF, RS. The models fitted with it are clearly indicated on the PDF information.

USAS - Uncontrolled Speed Active Safety

images/300/gas_safety_image_5_W.pngUSAS is an unique safety solution device, which exhausts pressure in a controlled and complete way, without ejection of parts when the cylinder has been stressed by uncontrolled return of the piston rod. This is typically caused by the seizure or jam of the die plates or stamped parts that, subjected to pressure thrust, are released in an uncontrolled manner. USAS usually does not activate after the first impact/shock, but only after a certain number of non controlled impacts.

USAS is activated by the upward shift of the bushing that takes the outer sealing element of the bushing onto the discontinuity on the inner wall of the cylinder. It is activated as a result of the abnormal mechanical load generated by the non controlled return of the piston rod, deforming the contact section of the C-ring, thus allowing the upward shift of the same bush.

USAS self activates without causing structural damages to the cylinder, further improving safety for users.

- Exhausts the pressure inside the cylinder when the piston rod is subject to non-controlled returns.

- Reduces the risk of ejecting structural parts of the cylinder.

- Renders the cylinder harmless.

- Activates itself automatically regardless of user intervention.

- Does not increase the price of the cylinders. 

The models fitted with it are clearly indicated on the PDF information.


 User Information


images/300/Nitrogen_Gas_Cylinder_User_Information1_H.jpg Charge only with Nitrogen Gas
images/300/Nitrogen_Gas_Cylinder_User_Information3_H.jpg All Special Springs nitrogen cylinders are designed with a stroke reserve from 1 to 3 mm (except M90/ TBM-TBI-TEM). Therefore, the nominal value (Cu) is fully applicable. However, it is recommended not to exceed 90% of Cu in practical use in order to avoid risk of any extra stroke caused by changes or errors in tools. This would result in irreparable damages to the cylinders and serious danger to personnel.
images/300/Nitrogen_Gas_Cylinder_User_Information4_H.jpg In presence of liquid or solid contaminants, use cylinders with SKUDO. In absence of cylindrs with SKUDO protection, a significant improvement could be obtained by mounting the cylinders in upside-down position.
 images/300/Nitrogen_Gas_Cylinder_User_Information5_H.jpg Avoid contact with contaminant (soda or chlorites) on the cylinders. If used for cleaning tools, we recommend you to carefully remove any remainng liquid from the cylinders.
 images/300/Nitrogen_Gas_Cylinder_User_Information6_H.jpg  Do not confuse the maximum speed with the recommended maximum number cycles/min, as indicated in each family of the product.
 images/300/Nitrogen_Gas_Cylinder_User_Information7_H.jpg Operating Temperature 
 images/300/Nitrogen_Gas_Cylinder_User_Information8_W.jpg Always fix the gas springs directly through the threaded holes on the bottom or with the fixing elements provided 
 images/300/Nitrogen_Gas_Cylinder_User_Information9_W.jpg  Use the threaded hole on the rod only for handling.
images/300/Nitrogen_Gas_Cylinder_User_Information10_H.jpg   When discharging using a DDS device, direct the gas flow away form operator.
 images/300/Nitrogen_Gas_Cylinder_User_Information11_H.jpg  Avoid any mechanical tooling or impact on the body and the rod.
images/300/Nitrogen_Gas_Cylinder_User_Information29_H.jpg  If a cylinder has structural damage, fully exhause all pressure before any form of handling. 
 images/300/Nitrogen_Gas_Cylinder_User_Information12_H.jpg  When charging do NOT exceed the maximum recommended pressure for each model.
 images/300/Nitrogen_Gas_Cylinder_User_Information13_H.jpg Any variation in temperature, respect to the nominal calculation value of 20°C, causes a change in gas pressure (P).
images/300/Nitrogen_Gas_Cylinder_User_Information14_H.jpg   Ensure that the rod is 100% extracted when charging. For cylindres without a threaded hole on the rod, initially charge to 5 bar (75 psi) to extract the rod completely, then charge to the required.
 images/300/Nitrogen_Gas_Cylinder_User_information28_H.jpg Before disposing of gas spring ensure that all residual pressure is fully exhausted.
 images/300/Nitrogen_Gas_Cylinder_User_Information15_H.jpg  On the catalogue it is indicated, for all models, both the isothermal end force, and the polytrophic one. 
The isothermal end force, with 100% Cu, is a value calculated on static conditions and can be considered suficient for a normal use of cylinders.
The polytophoic end force, with 100% Cu, is a more realistic value when the cylinder is working. Though, bein the temperature of the gas inside the cylinder not constant, and depending from several factors, the polytrophic end force should be calculated case by case. The influencing factors are, for example: nominal stroke, working stroke, press speed, number of cycles per minute, gas volume, working and environment temperature etc.
The values of the polytrophic force calculated at thermal regime are indicated 100% Cu, ca 30 SPM, constant press speed and environment at around 20°C.
images/300/Nitrogen_Gas_Cylinder_User_Information16_W.jpg  To calculate the intial force of each gas cylinder, multiply the maximum chargind pressure (P) to the area of sealing, rod or piston, of the gasket seal. 
 images/300/Nitrogen_Gas_Cylinder_User_Information17_H.jpg To calculate the intermediate isothermal force (Fxi) or polytrophic (Fxp) of a gas cylinder to a determinated working stroke (Cx), use the formula by replacing the relative numeric values.
images/300/Nitrogen_Gas_Cylinder_User_Information18_W.jpg   To determine the pressure level required to achieve a force (Fn) different from the nominal one (Fo), divide the required force (Fn) by the area of sealing, rod or piston, of the gasket seal.
 Do not exceed the maximum rod speed indicated for each model. Going beyond that limit could cause bad effects on safety and on the cylinders' duration
 images/300/Nitrogen_Gas_Cylinder_User_Information19_H.jpg  The recommended number of cycles per minute for each model is referred to the complete use of the stroke and is intended for "normal" uses on cut moulds. The minimum amount indicated is to be considered for the longest stroke, while the maximum amount is referred to the shortest stroke. in case of a partial use of the stroke, the number of cycles per minute could increase. We remind you that higher working frequencies respect of the recommended ones may have negative effects on the work duration. 

If correctly installed and in normal working conditions, the nitrogen cylinders Special Springs can guarantee a life of 200.00 linear meters of stroke. Heavy working conditions or external causes that would cause malfunctioning may reduce the life significantly. The warranty is valid for the indicated life within 2 years from the purchase date. Either any different use respect of the prescriptions and guidelines provided and specified with the products, or mechanical damages would cause the immediate warrenty decadence. Warranty legal terms on

 images/300/Nitrogen_Gas_Cylinder_User_Information20_H.jpg  All cylinders which can be connected ot the system and are specifically coded (__-N/ __-NA) are supplied without the one-way valve, without pressure and with only the closure plug of the connection hole (excluding M90, M200, RV170, RV320). If you wish to convert independent cylinders into system-connectable cylinders, order the neccessary hoses and connections, and follow the specific instructions for every series published on site

 a) Model code
b) Revision indicator
c) Hosed-system version
d) Batch number
e) General info
f) Subject to OE/PED 97/23/EC
g) Over stroke active safety
h) Over pressure active safety
i) Uncontrolled speed active safety
l) Maintenance kit

 images/300/Nitrogen_Gas_Cylinder_User_Information22_W.jpg All nitrogen cylinders totally satisfy the European Directive on pressure devices 97/23/EC. The European Directive on pressure equipments 97/23/EC, entered into force on 29th May 2002 for all European Community, prescribes and defines as pressure equipments the receptacles, the tubes and accessories built to contain pressurized fluids when the maximum acceptable pressure PS of the fluid is > of 0.5 bar. In particular, the directive 97/23/EC foresees the classifcation into categories (I,II,III) with EC mark and identification number of producer (mandatory for II and III, discretionary for I) for containers by which result of pressure P(bar) X fluid volume Vo(dm3) is =/> of 50. All the gas cylinders by which result of P x Vo is
 images/300/Nitrogen_Gas_Cylinder_User_Information23_H.jpg We recommend all die-markers to deliver all tools with the instructions sheets provided with cylinders and accessories supplied by Special Springs. 
 images/300/Nitrogen_Gas_Cylinder_User_Information27_H.jpg If pressure losses occur after extended use of particularly heavy applications, this indicates that the sealing gaskets are worn or damaged. Using special tools and kits, and with the support of videos and detailed instructions, it is possible to restore the original seal and guide conditions. Maintenance must only be conducted by qualified personnel. Errors would cause serious injury or reduce the working life of the cylinders. Before carrying out any work on the system, fully exhaust all pressure and ensure that the rod is fully retracted to the body.
 images/300/Nitrogen_Gas_Cylinder_User_Information24_W.jpg As the guidelines of the PED 97/23/EC instruction provide for, the company that arranges the maintenance of the cylinders laser etched EC by the producer (P x Vo =/> 50), takes charge of making them checked by a certified and qualified company. Otherwise, these maintenances could be carried out exclusively by Special Springs.
images/300/Nitrogen_Gas_Cylinder_User_Information26_W.jpg Kit made of: Assembled busing, one way valve, lubricant and grease, instructions sheet.


N2 Benefits


 Less Space
Benefits - Considerable reduction of: required surface, height, oppupied volume and retaining and pre-load devices.
Result - Great saving of money


Less Height

Benefits - Considerable height reduction for the same working deflection and force. Compact tool construction.
Result - Great saving of money


 Large Forces
Benefits - No pre-load. Easier and quicker fitting.
Result - Great saving of money


Controlled Forces
Benefits - Balanced force on each contact point. Forces may be positioned exactly where required. System may be constantly monitored for pressure.
Result - Constant production conditions of piece-parts. Longer life for punches and tools. Money saving.


 Almost Constant
Benefits - Maximum control of piece-parts during forming and drawing operations.
Result - Controlled production conditions on piece-parts. Less rejection of piece-parts. Money saving.


Adjustable Forces
Benefits - Cylinders applied to provide the real forces required. Assurance of defined forces. The same cylinder may be re-used for different power application.
Result - Flexible usage. Saving of money


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