An air compressor that raises the air-suspension seats in off-highway vehicles uses injection-molded plastic parts instead of those made with die-cast aluminum. The compressor, from Thomas Industries, Sheboygan, Wis., is part of an inflated rubber bladder under the seat within the seat suspension from Sears Manufacturing, Davenport, Iowa.

The compressor positions the operator to a desired height, and provides suspension for better performance.

Injection-molded parts replaced a die-cast aluminum housing and internal mechanical parts. This lets Thomas engineers more closely monitor quality. They developed new material combinations for the piston cup and cylinder sleeve and combined parts where possible.

The compressor is a redesign of a previous model which required higher performance in a smaller package. The compressor produces between 80 to 120 psi to lift the seat.

An air compressor designed for an airsuspension seat replaced die-cast  aluminum with injectionmolded parts.

An air compressor designed for an airsuspension seat replaced die-cast aluminum with injectionmolded parts.



A hybrid cylinder operates on pneumatics and is regulated 		 hydraulically.

A hybrid cylinder operates on pneumatics and is regulated hydraulically.


A new hybrid cylinder from RBHybroDynamics, Lynnwood, Wash., combines pneumatics and hydraulics. The air-hydraulic cylinders belong to a unique class of actuators that operate using compressed air but are regulated hydraulically. These cylinders provide a smooth displacement typical for hydraulic cylinders.

Air-hydraulic cylinders are interchangeable with conventional pneumatic cylinders and are easily integrated into existing pneumatic circuits to replace air cylinders. They are also a good alternative in new pneumatic and hydraulic designs. Hybrid cylinders can be considered before hydraulics for systems equipped with conventional air cylinders but with requirements for better positional control and operational stability despite irregular loads or pressure variations. They can also be built with FDA-compliable materials.