The patent application discloses a method of compressing air. The method for designing a more efficient reciprocating piston compressor comprising the steps of: providing an air compressor having a first compression stage adapted for compressing gas from a low pressure to an intermediate pressure and including a first piston connected to reciprocate in a first cylinder, a second compression stage adapted for compressing gas from the intermediate pressure to a higher pressure and including a second piston connected to reciprocate in a second cylinder, and a motor connected to reciprocate said first piston in said first cylinder over a stroke and said second piston in said second cylinder over a stroke; and establishing a sufficiently fewer number of strokes over which the gas to be pressured starting from the atmosphere pressure.

The disclosure relates to a leveling system useful for self-leveling casters on suspension systems of harvesters, such as self-propelled windrowers. The suspension system utilizes position sensors and hydraulic actuators operably linked to each caster, the hydraulic actuators responding to a rotational position of the caster as detected by the respective position sensor to level the caster.

A shock absorber with a vehicle height adjustment function according to the present invention includes a shock absorber main body that includes a cylinder filled with liquid, a piston that partitions inside of the cylinder into an extension side chamber and a compression side chamber, a piston rod coupled to the piston, a suspension spring that biases the shock absorber main body in an extending direction, a reservoir that accumulates liquid, a damper circuit that is connected to the extension side chamber, the compression side chamber, and the reservoir and generates a damping force in the shock absorber main body at the time when the shock absorber main body expands/contracts, a pump that is able to suck liquid from the reservoir and discharge the liquid, and a switching valve that is installed between the shock absorber main body and the damper circuit and the pump and switches a damper mode in which the shock absorber main body is connected to the damper circuit so as to generate a damping force in the shock absorber main body and a vehicle height adjustment mode in which the shock absorber main body is connected to the pump.

A suspension system includes a spring support for a vehicle support spring. A spring collar supporting the vehicle support spring is selectively adjustable with respect to position by a pressurized-medium supply with the aim of adjusting the level of a vehicle body. The spring support is constructed as a hydropneumatic spring having a hydraulic volume, which can likewise be adjusted relative to a pneumatic storage element.

A hydraulic shock absorbing apparatus for a vehicle includes left and right front wheels, left and right arms, and hydraulic shock absorbers provided between a vehicle body and the left and right arms. A first end portion of each hydraulic shock absorber includes a cylinder main body partitioned into a first oil chamber and a second oil chamber by a piston. A second end portion of the hydraulic shock absorber includes a piston rod including the piston. A reserve tank is connected to one hydraulic shock absorber via a first hydraulic oil passage and connected to the other hydraulic shock absorber via a second hydraulic oil passage. The first hydraulic oil passage and the second hydraulic oil passage are individually connected to a third oil chamber of the reserve tank.

An air-ride axle/suspension system for a heavy-duty vehicle. A frame and at least a pair of suspension assemblies support opposite ends of an axle for movement relative to the frame. An air spring is associated with one of the suspension assemblies that establishes a first relative position between the axle and the frame as a function of fluid pressure in the air spring. A tire and wheel assembly is operatively mounted to an end portion of the axle associated with the air spring. A sensor detects an inflation condition of the tire and wheel assembly. A venting system exhausts fluid pressure from the air spring to establish a second relative position between the axle and the frame that is different than the first relative position in response to detecting a predetermined inflation condition of the tire and wheel assembly.

A vehicle height adjustment device includes: a pressure tank capable of storing air in a compression state; a plurality of vehicle height adjustment units that are provided in correspondence with wheels of a vehicle and individually adjust vehicle heights at the respective wheels by supplying the air from the pressure tank or returning the air to the pressure tank; an information acquisition unit that acquires turn route information during travel of the vehicle; and a control unit that raises the vehicle height at the vehicle height adjustment unit on a turn outer side more than the vehicle height at the vehicle height adjustment unit on a turn inner side such that the vehicle takes a tilt posture on the basis of the turn route information when the vehicle turns.

A hydraulic actuator for a vehicle suspension includes: a pump assembly including an electric motor coupled to first and second pumps to transfer hydraulic fluid to a discharge header; a first isolation valve having an elastomeric seat and configured to selectively block fluid flow from a port in fluid communication with a height-adjustable damper to the discharge header; and a second isolation valve having a metal seat and connected in series with the first isolation valve to selectively block fluid flow from the port to the discharge header. The first pump transfers hydraulic fluid from a supply fluid passage to a first discharge header, and the second pump transfers hydraulic fluid from the supply fluid passage to a second discharge header. A recirculation valve selectively controls fluid flow from the second discharge header to the supply fluid passage.

A vehicle-height adjusting system includes: vehicle-height adjusting actuators each for adjusting a vehicle height for a corresponding one of wheels; a pressure medium supplier for supplying a pressure medium from a tank to each of the vehicle-height adjusting actuators; and a vehicle height adjuster for adjusting the vehicle height for each wheel. The vehicle-height adjusting actuators include a left vehicle-height adjusting actuator and a right vehicle-height adjusting actuator. The vehicle height adjuster includes a supply amount controller configured to control the pressure medium supplier such that substantially the same amount of the pressure medium is to be supplied from the tank to the left vehicle-height adjusting actuator and the right vehicle-height adjusting actuator, when at least one of the wheels is in contact with an uneven road surface.

Disclosed herein is a pneumatic adjustment apparatus for a vehicle. The pneumatic adjustment apparatus includes a block including a flow path formed therein, the flow path being configured for a fluid to move through the block, a compressor coupled to the block and configured to communicate with the flow path and to compress the fluid, a driver coupled to the block, connected to the compressor, and configured to drive the compressor, and a controller coupled to the block and configured to open and close the flow path.