1. What are DA units used for?
DA stands for double acting non-adjustable hydraulic damper. Applications range from doors and lids to amusement rides and conveyor systems.

2. What is a Towbar?
A specially designed DA which dampen abrupt starts and stops of power and free conveying systems.

3. What are the OEM small series shock absorbers?
The OEM small series shock absorbers are a series of adjustable shock absorbers that have bore siezes of 1/4 inch to 5/8 inch in diameter and stroke lengths of .28 inches to 2 inches depending on model.

4. Are there any accessories available for the OEM small series shock absorbers?
Enidine Incorporated offers a full assortment of accessories that include stop collars, jam nuts, cylinder clevises, foot mounts and cap pads. Not all accessories are available with all models.

5. How is the usable adjustment settings graph used?
Locate the applications impact velocity on the Y-axis and the selected model graph line. Follow the impact velocity horizontally until it intersects the selected model graph line. Follow the intersection point vertically down to the X-axis. The value at the X-axis is the maximum allowable adjustment setting.

6. How are the OEM series shock absorbers adjusted?
The small series OEM shock absorbers can be adjusted by rotating the adjustment knob at the back of the shock absorber.

7. What is the adjustment range of the small bore OEM series shock absorbers?
The OEM small bore series shock absorbers have an adjustment range of 0 minimum damping to 8.0 maximum damping.

8. What type of damping do the small bore OEM series shock absorbers provide?
The OEM .1 through .5 provide dashpot type damping. The OEM 1.0, OEM 1.25 x 1 and OEM 1.25 x 2 provide conventional type damping. \

9. Can the OEM series shock absorbers be orificed for a specific application?
Yes. These shock absorbers can be orifice to provide specific damping for a particular application. When the shock absorbers are custom orifice they are referred to as CBOEM shock absorbers.

10. When should an Air/Oil tank be considered?
A. When the application's energy per hour exceeds the maximum rating for self contained units.
B. When the piston rod sequence must be controlled.

11. How much additional energy capacity is obtained when using an Air/Oil tank?
Generally the shock absorber's energy capacity per hour can be increased by 20%.

12. What is the maximum pressure that an Air/Oil tank can be used at?
100 PSI

13. What does HD stand for?
HD is the name of Enidine Incorporated's Heavy Duty series of shock absorbers.

14. Does the HD model utilize a mechanical spring return?
No, the design incorporates an air charged bladder accumlator.

15. How does the accumulator in an HD shock keep the piston assembly extended?
Charging the bladder with air pressure creates a preload across the piston rod area of the unit which holds the piston assembly fully extended.

16. What is the charge pressure on an HD shock to be used?
Typically the HD models are charged at the factory to between 30 and 40 psi.

17. What is an Enidine Incorporated CBOEM shock absorber?
CBOEM is a custom orifice non - adjustable unit, which meets specific application requirement.

18. What are the most common names/types of shock absorbers?
Dampers, Buffers, Dashpost, Snubbers and Isolators.

19. What is Conventional Damping?
Allows linear deceleration by providing a constant shock force over the entire stroke.

20. What is Progressive Damping?
This provides deceleration with a gradually increasing shock force. The initial minimal resistance at impact protects delicate loads and machinery from damage.

21. What is Dashpot Damping?
This provides the largest shock force at the beginning of the stroke when the impact velocity is highest.

22. What are the advantages of an Enidine Incorporated shock absorber over rubber bumpers and springs?
Longer Life - It significantly reduces shock and vibration to machinery.

Higher Operating Speeds - Machines can be operated at higher speeds because of the Shock Absorber control or gently stop moving objects.

Improved Production Quality - Harmful side effects of motion, such as noise and vibration and damaging impacts are moderate or eliminated, so the quality of production is improved.

Safer Machinery - Protects machinery and operators by offering predictable, reliable and controlled deceleration.

Improved Production Quality - Harmful side effects of motion, such as noise and vibration and damaging impacts are moderate or eliminated, so the quality of production is improved.

Safer Machinery - Protects machinery and operators by offering predictable, reliable and controlled deceleration.

23. How do you determine whether an application will exceed 10 degrees(+/-5%) allowable angle?
The maximum side-load angle allowed by Enidine Incorporated is 10° (+5°). For a rotating arm, door, lid or circuit breaker for example, the moving load should be perpendicular to the center-line of the piston rod when it is halfway through the stroke.

24. What is the standard operational temperature range of the OEM and PM/PRO series shock absorbers?
The standard operational temperature range is 15 to 180°F (-10 to 85°C).

1. What is isolation efficiency?
Isolation efficiency is the percent of vibration force or motion that is not transmitted through the vibration mount.

2. What is G?
G is the value of acceleration produced by the force of gravity.

3. What is noise?
Noise is vibration of air. Vibrations of the air typically have a frequency and an intensity (loudness) level. Noise is what you hear with your ear.

4. How can noise be reduced?
In order to be able to reduce disturbing noise levels, it is very important to identify two key elements. The first element is the source of the noise. The second is the frequency of the noise. Typically a vibration mount designed in accordance with vibration.

5. What is excitation frequency?
Defined as the number of oscillations per unit time that an external force or displacement is applied to a system, can also be referred to as 'forcing frequency'. Typically measured in Hz (cycles per second).

6. What is natural frequency?
Is the frequency at which oscillating system will vibrate if displaced from its equilibrium position and allowed to vibrate freely. Often described as Fn and measured in Hz(cycles per second).

7. What is resonance?
When the frequency of excitation is equal to the natural frequency of a system, resonance occurs. When this happens there is amplification of the vibration input to the system and this can only be limited by the damping in the isolation system.

8. What is fragility?
Describes the amount of shock or vibration that a particular piece of equipment can withstand. Isolation systems are often designed to limiit the transmission of forces to the fragility level of the isolated equipment.

9. What is damping?
Describes the dissipation of energy with time or displacement. There are many common types of damping; viscous damping (orifice in a hydraulic shock absorber), hysteretic damping (occurs in an elastomeric isolator), and coulomb damping (as in a wire rope isolator).

10. What is critical damping?
Critical damping is the smallest amount of damping required to return a system to its equilibrium position without oscillation.

11. What is damping factor?
A dimensionless ratio, which defines the amount of damping in a system. Commonly defined as C/Cr.

12. What is coulomb damping?
The system is said to have coulomb or dry friction damping if the damping force in a vibratory system is constant and independent of position or velocity of the system.

13. What is loss factor?
Loss factor is the measure of the damping value in an elastomer.

14. How much damping can be expected from a Wire Rope Isolator (WRI)?
WRI have between 5% and 20% damping. The amount of damping is related to wire diameter and stroke. The larger the wire diameter, the more damped (and stiffer) the isolator. Damping can be less with small amplitude vibration.

15. Does Enidine Incorporated manufacture Wire Rope Isolators (WRI) for corrosive environments?
Yes, The Enidine Incorporated standard WRI product is made from stainless steel and aluminum. The standard product can be used successfully in most normal indoor environments. Where greater protection is required, such as exposure to salt water or corrosive chemicals, stainless steel should be considered.

16. Do the Wire Rope Isolators (WRI) provide the same stiffness in tension and compression?
No, the tension stiffness is significantly greater than the compression stiffness. Also, Enidine Incorporated does not recommend that the WRI be used in tension.

17. What type of mounting option should I select on a Wire Rope Isolator (WRI)?
Application dependent, but in general, for shock applications use mounting options "B," "D," or "E".

18. What does the WR series number represent on standard Wire Rope Isolator (WRI)?
The number following WR represents the wire diameter in 32nd of an inch. The WR5 series isolators use 5/32” diameter wire.

19. Do the three digit Wire Rope Isolator (WRI) model index numbers have any meaning?
The difference between a 200, 400, 600, and 800 index number has relative meaning within a series. The larger the number the taller the isolator but the lower the isolator stiffness.

20. Does the Wire Rope Isolator dash number at the end of the model number have meaning?
In general it represents the number of loops in the isolator.

21. How do Wire Rope Isolators (WRI) compare to elastomers regarding use over a broad temperature range?
The WRI can be used over a greater temperature range with less change in performance. Proper elastomer selection will make elastomers useful for most applications.

22. Are elastomeric parts or Wire Rope Isolators (WRI) better for severe shock applications?
WRI are naturally well suited for shock isolaton. Elastomeric parts can be specifically designed for severe shock and perform very well.

23. Are elastomeric parts or Wire Rope Isolators (WRI) better suited to very specific multi axis stiffness requirements?
Elastomers are more flexible in creating custom isolator performance in multi axis systems. The WRI can also be wound differently to customize stiffness.

24. Which is better suited for high frequency vibration, an elastomer or Wire Rope Isolator (WRI)?
Elastomers are typically better for high frequency vibration (>500 Hz). Both are well suited for mid frequency isolation (20 to 100 Hz).

25. Are elastomers or Wire Rope Isolators (WRI) better suited for severe fluid contamination?
WRI are less susceptible to fluid contamination but proper elastomer selection can typically provide adequate protection.

26. What are degrees of freedom?
This represents the six directions of movement that a vibration isolation device such as an elastomer or wire rope isolator is capable of traveling.

1. What is an Air Actuator?
A device, which induces action or motion with compressed air being the medium through which the power is transmitted. Similar in function to an air cylinder.

2. What is an Air Spring Assembly?
An air spring flexible member complete with end closure components (retainers) ready to be mounted in place and used as an air actuator or vibration isolation mount. Also referred to as an Air Spring or Air Bag.

3. What is Amplification?
Act of amplifying; increasing; enlarging.

4. What are Bellows?
An air spring having one, two or three convolutions in the flexible member.

5. What are Blind Taps?
An attachment provision recessed in the retainer, closed at the bottom to prevent air loss. A bolt or shoulder stud may be inserted to attach the air spring to machinery.

6. What are Bolted Bead Rings?
A ring used to attach certain bellows type flexible members to the mounting surface. Used in place of the conventional upper and lower crimped-on retainers.

7. What are Bumpers?
An internal compression stop. Generally a molded rubber part attached inside the air spring assembly. It aids in preventing internal damage to the air spring assembly due to heavy loads coupled with severe compression and helps to prevent damage in the event of air loss.

8. Define Convolution?
On a bellows type air spring, that part of the flexible member forming an annular protrusion larger than the O.D. of the end retainers or the girdle ring(s).

9. Define CPM?
Cycles per minute-a unit of measure of the frequency of any vibration.

10. Define Crimped Design?
That type of air spring assembly in which the flexible member is permanently attached to the end retainers by mechanically bending the retainers around the bead wires molded into the flexible member.

11. Define Crimp Ring?
A solid metal ring used to attach a sleeve or molded sleeve bellows type flexible member to the end retainers by swaging the flexible member between the crimp ring and the end retainer.

12. Define Effective Area?
A specific area found by dividing the load supported by the air spring by its internal gas pressure at any given spring position. The effective areas of the rolling lobe and sleeve type assemblies are more constant over the stroke than that of a bellows. However, all air springs generally have decreasing affective areas with extension.

13. Define Flexible Member?
The rubber-fabric component in an air spring assembly consisting of special reinforcing cords sandwiched within rubber.

14. Define Forced Frequency (f1)?
The number of oscillations per unit of time of an external force acting on a mass. Sometimes referred to as the disturbing or exciting frequency and measured in CPM or Hertz. Also see Natural Frequency.

15. Define Girdle Ring?
A rubber covered bundle of wires that restricts the diameter of the flexible member at the attachment point to form double or triple convolutions.

16. Define Height?
A dimension always measured linearly along the stroke of an air spring assembly between the parallel planes of the attachment surfaces of the upper retainer and lower retainer or piston.
a. Bumper Contact Height: That height at which the bumper contacts the opposite retainer.
b. Compressed Height: That height at which the deflection of the air spring assembly must be limited by external means to prevent possible damage to the air spring assembly. Also referred to as "Compressed Height without a Bumper.
c. Design Height: The selected operational height of an air spring when mounted and inflated with the mass at rest.
d. Design Height Range: A predetermined range of heights within which the design height should be selected for optimum performance as an isolator.
e. Height Limit (Actuator): The extension limit of the air spring assembly. A reduction in life is probable above this limit due to the repetition of highly concentrated stresses. Extension restraints are required.
f. Maximum Extended Height: The maximum operational height of the air spring assembly. Exceeding this height may result in structural damage to the air spring assembly. Extension restraints are required.
g. Metal to Metal Height: That height where the air spring assembly is compressed to the point where the metal or plastic retainers contact.

17. Define Hertz?
Cycles per second (Hz)-a unit of measure of the frequency of any vibration.

18. Define Isolator (Vibration)?
A device used to join one object to another and restrict the transmission of vibration to some degree.

19. Define Load Range (Isolators)?
The largest diameter the air spring assembly will attain at an internal pressure of 100 PSIG or less, including a factor for growth over time.

20. Define Maximum Inflated Diameter (Max O.D.)?
The largest diameter the air spring assembly will attain at an internal pressure of 100 PSIG or less, including a factor for growth over time.

21. Define Meniscus?
That portion of the flexible member of rolling lobe and sleeve type air springs that curves under (reverses) in the transition from working diameter to the piston diameter.

22. Define Meniscus Height (M)?
The distance measured from the bottom of the meniscus to the bottom of the piston. Applies to rolling lobe and sleeve type air spring assemblies only.

23. Define Natural Frequency (fn)?
The number of cycles per unit time that a mass vibrates on its spring medium. Usually considered only in the vertical mode and expressed in Hertz (cycles per second) or CPM (cycles per minute).

24. Define Nominal Outside Working Diameter?
This is the one or two digit number that follows the R, S or B in the product description. It is the approximate working diameter of the super-cushion air spring.

25. Define NPTF?
American National Standard Dry seal Pipe Threads N = National (American) Standard, P = Pipe, T = Taper, F = Fuel and oil. Goodyear recommends always using a suitable thread sealant, such as Teflon tape, for additional leak protection.

26. Define Piston?
A rigid structure over which the flexible member rolls. The contour of the piston affects the operating characteristics of the air spring assembly.

27. Define PSIA?
Pounds per square inch, absolute.

28. Define PSIG?
Pounds per square inch, gauge. The pressure measured by a gauge within a closed system. Zero PSIG = 14.7 PSIA at sea level.

29. Define Rebound?
The extension of the air spring above its design height.

30. Define Reinforcement?
A structure of cords built into the flexible member to control its shape and to strengthen its wall structure against internal gas pressure. Normally this is two bias plies of synthetic cord.

31. Define Restraining Cylinder?
A rigid cylinder attached at one end to the plane of the mounted mass. When dimensionally matched to restrain the O.D. of the air spring, it also provides additional lateral support. It can eliminate the need for more elaborate stability arrangements.

32. Define Rolling Lobe?
Rolling lobe air springs incorporate a piston, which allows the flexible member to roll along the piston's surface as forces change. Also referred to as a "piston-type" air spring.

33. Define Resonance?
The phenomenon shown by a vibrating system, which responds with maximum amplitude under the action of a harmonic force. Resonance occurs when the forced frequency is the same as the natural frequency of the vibrating body.

34. What is a Retainer?
The end enclosure of an air spring assembly. Two retainers are used in each air spring assembly. Generally made of metal and supplied with blind taps, protruding bolts, or a combination of these to facilitate mounting the assembly to equipment.
a. Upper Retainer: Refers to that retainer which contains the air fitting. It need not be in the up position.
b. Lower Retainer: Refers to that retainer with no air fitting. In a bead type rolling lobe assembly, the lower retainer extends through or attaches to the piston.

35. What is a Shoulder Stud?
A threaded bolt with a shoulder that can only be driven a specified depth into a blind tap. The shoulder limits the depth, and prevents fracture of the bottom of the blind tap.

36. What is a Sleeve?
An air spring flexible member manufactured without internal bead wires.

37. What are Sleeve Type Assemblies?
A rolling lobe type assembly utilizing a flexible member without internally molded bead wires.

38. What is Stroke (Total)?
The difference between the maximum extended height and the compressed height.

39. Stroke (Usable)?
That part of the total stroke, which can be utilized repeatedly in actuator applications. It is measured starting at the compressed height and is the difference between the compressed height and the actuator height limit.

40. What is a Stud?
A threaded bolt that can be permanently attached to the retainer or inserted into a blind tap in the retainer. Also see Shoulder Stud.

41. What is a Swaged Design?
That type of air spring assembly in which the flexible member is permanently attached to the end retainers with crimp rings. The flexible member is compressed between the end retainer and crimp ring by mechanically reducing the diameter of the crimp ring, thus creating an airtight seal.

42. What is Transmissibility?
The ratio of transmitted force to exciting force.

43. What is a Tank Valve?
A tire type inflation valve which can be used with an air spring assembly for manual inflation.

44. Define UNC?
Unified national coarse (thread).

45. Define UNF?
Unified national fine (thread).