Air springs control ride-height and load compensation on most heavy trucks today. An engine-driven air compressor maintains constant line pressure. As the distance between the axle and the frame decreases to less than a permissible minimum, a mechanical linkage actuates the air-leveling valve that admits air into the bladder. The same valve exhausts air when the distance between the frame and axle becomes excessive.
With no reservoirs to leak and no poppets to jam, the compact valve is unaffected by normal contamination. Of rotary design and containing only one moving part, the valve relies on lapped surfaces to affect a seal. Compressed air does not flow across sealing surfaces, but directly through the inside diameter of the seal. The relative movement of two circular, overlapping ports affects valve operation to ramp the flow rate and eliminate full-on/full-off behavior.
A 1.58 deadband prevents nuisance valve actuation during normal suspension travel. Exhaust and fill times are 11/2 to 21/2 times quicker than those of other systems. And an integral fast-flow dump port permits 10-sec system depressurization prior to driving away from parked trailers.
Mechanical link between truck’s axle and frame-mounted air-leveling valve helps maintain the pre-set ride-height pressure in the air
Air, together with any contaminants, flows into the leveling valve through the center of its pressure seal and does not flow across sealing surfaces.
Submit your ideas and rough drawings for this section to John Lewis, Designer's Corner, Design News, 275 Washington St., Newton, MA 02458
Paul O'Reilly Barksdale Inc. 3211 Fruitland Ave. Los Angeles, CA 90058 (800) 835-1060
The engineers and inventors of the post WWII period turned their attention to advancements in electronics, communication, and entertainment. Breakthrough inventions range from LEGOs and computer gaming to the integrated circuit and Ethernet -- a range of advancements that have little in common except they changed our lives.
Neil Fromer is the executive director of the Resnick Institute, a program for energy and sustainability at the California Institute of Technology, working to develop new ideas and research technologies related to providing a sustainable future. He spoke to us about the severity of the current drought in California and how solar energy can help prevent such situations in the future.
From home enthusiasts to workers on the manufacturing floor, everyone's imagination is captured by the potential of 3D printing. Prototyping, spare parts creation, art delivery, human organ creation, and even mass product production are all being targeted as current and potential uses for the technology.
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.