PLEASE NOTE The information contained in this publication is intended to provide a general guide to the characteristics and applications of these products. The material, herein, was through engineering design and development, testing and actual applications and is believed to be reliable and accurate. However, Firestone makes no warranty, express or implied, of this information. Anyone making use of this material does so at his own risk and assumes all liability resulting from such use. It is suggested that competent professional assistance be employed for specific applications. 1 Advantages...

HISTORY In the early 1930's, the Firestone Tire and Rubber Company began experiments to develop the potential of pneumatic springs. Between 1935 and 1939, several makes of U.S. automobiles were equipped with air springs and extensively tested to prove the potential of automotive air suspension systems. They were never put into production, however, because significant developments in steel spring design gave an improved ride at much lower cost than the air spring system at that time. In 1938, the country's largest manufacturer of motor coaches became interested in using air springs on a new design...

AIR SPRINGS GIVE FLEETS A COMPETITIVE Primary Trailer Lift Axle Today's trucking industry has become far more efficient than ever before. In many cases it's a matter of survival. That's why more and more fleets are specifying air suspensions for their new trucks and It is a well documented fact that trucks and trailers with air suspensions suffer much less "wear and tear" than those that ride on steel. This means longer cab and vehicle life, lower operating costs, less down time and fewer failures of expensive on-board electronic equipment. It's also a fact that when trucks ride better, so does...

Drive Axle systems also reduce operating costs by reducing maintenance and increasing the life of the trailer. Firestone Airide® air springs isolate the destructive shock inputs from the road surface. That means less wheel hop and longer life for the trailer (and tractor). Deadheading tankers and flat beds take much less punishment, and electrical, reefer unit and upper coupler problems are greatly reduced, to mention a few. There are also fewer problems with door seals, latches, hinges, wiring and light The truth is, nothing offers a greater payback than air suspensions for trailers. You get...

TERMS AIR SPRINGS & SUSPENSIONS PRESSURE 8 PROCESS TERMS Absolute Pressure. The pressure in a vessel located in a complete vacuum. Usually determined by adding 14.7 to the gauge pressure. Absolute pressure gauge pressure + atmospheric pressure. perature, change with heat transfer to the air spring structure. To account for this, air spring dynamic operation is calculated by the use of what is known as the polytropic exponent (n). n 1.38 is the 9enerally accepted value for air springs. AIR SPRING COMPONENT TERMS Adiabatic Process. All the calculation variables, volume, pressure, and temperature,...

Bumper. Usually, these are made of rubber, plastic, or rubber and fabric materials. They are used to support the vehicle when there is no air in the air springs, when the vehicle is not in use, or when there is a system failure on the road. They will also, to some degree, cushion the shock of very severe axle force inputs to prevent damage to both the Airide(R) spring assembly and to the vehicle. Clamp Ring. A metal band placed near the end of a beadless flexible member. It is swaged tightly in place to secure the beadless flexible member to the upper end cap and piston. Flexible Member. The...

Compression Stroke (Jounce). The reduction in heioht from the normal desion heioht of the sprino as it cycles in dynamic operation. Curb Load. The normal minimum static load the air spring is expected to support. It is a zero payload condition, but includes that portion of the unloaded vehicle that is supported by the axle. It is this axle load divided by the number of air springs working with the axle and adjusted according to any lever arm ratio incorporated in the suspension. Design Load. This is the normal maximum static load the air spring suspension is expected to support. It is the rated...

SUSPENSION RELATED TERMS Height Sensor. An electronic device that senses the position of a suspension or other mechanical device. The output signal from this device is sent to a control circuit which then exhausts or adds air to the air spring through a solenoid valve. Leveling Valve. A pneumatic valve that senses the distance between the vehicle frame and the axle via a mechanical linkage which adds or exhausts air pressure to maintain a constant vehicle height. Sprung Mass Natural Frequency. The speed of vertical oscillations of the suspended vehicle sprung mass. Can be expressed in cycles...

OUTER COVER INNER LINER FLEXIBLE MEMBER CONSTRUCTION An air spring is a carefully designed rubber and fabric flexible member which contains a column of compressed air. The flexible member itself does not provide force or support load; these functions are Firestone air springs are highly engi- neered elastomeric flexible members with specifically designed metal end closures. The standard two-ply version is made up of four layers: • Inner Liner. An inner liner of calendered rubber. reinforced rubber with the cords at a specific bias angle. • Second Ply. A second ply of fabric- reinforced rubber...

Although the two-ply air spring is standard, many of our air springs are also available in fourJply rated construction for use at higher pressures. Each air spring's flexible member is identified by a style number, which is molded in during the curing (vulcanization) process. Examples would be 16, 22, 313, 1T15M-6, etc. Ths identfies only the rubber/fabric flexible member.., not the complete assembly.

IEVERSIBLE SLEEVE STYLE AIR SPRING WITH CRIMPED BEAD PLATE Stud. Mounting stud. Usually 1/2"-13 UNC. Combination Stud. Combination UNF mounting stud with NPT internal air entrance. 3/4"-16 9 gauge Bead Plate. corrosion(.49") carbon resistance. for steel, plated Permanently crimped to the flexible member to form an airtight assembly which allows for leak testing before the unit leaves the factory. Flexible Member. Wall gauge is .25 inches. See page 9 for detailed information. Bumper (Optional). An internal device to prevent damage to the air spring during times when no air is in the system.