| 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? |
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| 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? |
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| Act of amplifying; increasing; enlarging. |
| 4. What are Bellows? |
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| An air spring having one, two or three convolutions in the flexible member. |
| 5. What are Blind Taps? |
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| 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? |
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| 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? |
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| 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? |
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| 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? |
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| Cycles per minute-a unit of measure of the frequency of any vibration. |
| 10. Define Crimped Design? |
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| 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? |
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| 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? |
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| 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? |
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| 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.
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| 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.
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| c. |
Design Height: The selected operational height of an air spring when mounted and inflated with the mass at rest.
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| d. |
Design Height Range: A predetermined range of heights within which the design height should be selected for optimum performance as an isolator.
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| 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.
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| 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.
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| g. |
Metal to Metal Height: That height where the air spring assembly is compressed to the point where the metal or plastic retainers contact.
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| 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? |
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| 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? |
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Pounds per square inch, absolute.
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| 28. Define PSIG? |
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Pounds per square inch, gauge. The pressure measured by a gauge within a closed system. Zero PSIG = 14.7 PSIA at sea level.
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| 29. Define Rebound? |
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The extension of the air spring above its design height.
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| 30. Define Reinforcement? |
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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.
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| 31. Define Restraining Cylinder? |
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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.
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| 32. Define Rolling Lobe? |
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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.
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| 33. Define Resonance? |
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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.
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| 34. What is a Retainer? |
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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. |
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| 35. What is a Shoulder Stud? |
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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.
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| 36. What is a Sleeve? |
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An air spring flexible member manufactured without internal bead wires.
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| 37. What are Sleeve Type Assemblies? |
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A rolling lobe type assembly utilizing a flexible member without internally molded bead wires.
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| 38. What is Stroke (Total)? |
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The difference between the maximum extended height and the compressed height.
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| 39. Stroke (Usable)? |
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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.
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| 40. What is a Stud? |
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A threaded bolt that can be permanently attached to the retainer or inserted into a blind tap in the retainer. Also see Shoulder Stud.
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| 41. What is a Swaged Design? |
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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.
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| 42. What is Transmissibility? |
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| The ratio of transmitted force to exciting force. |
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| 43. What is a Tank Valve? |
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| A tire type inflation valve which can be used with an air spring assembly for manual inflation. |
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| 44. Define UNC? |
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Unified national coarse (thread).
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| 45. Define UNF? |
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| Unified national fine (thread). |
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