Abstract: A multi-chamber blowoff valve is provided for releasing excess air pressure from a duct system associated with a vehicle. The blowoff valve has a valve housing, an engine-air interface, and a multiple piston assembly. The valve housing is configured to secure to the duct system at a duct-air interface. The engine-air interface is configured to allow air in and out of the valve housing. The multiple piston assembly is disposed within the valve housing and includes an upper piston and a lower piston that move in unison. The multiple piston assembly is configured to be in a closed position while a pressure differential is above a certain threshold and to be in an open position while the pressure differential is below said certain threshold. While in the open position, a portion of the air in the duct system is released.

Abstract: A multi-chamber blowoff valve is provided for releasing excess air pressure from a duct system associated with a vehicle. The blowoff valve has a valve housing, an engine-air interface, and a multiple piston assembly. The valve housing is configured to secure to the duct system at a duct-air interface. The engine-air interface is configured to allow air in and out of the valve housing. The multiple piston assembly is disposed within the valve housing and includes an upper piston and a lower piston that move in unison. The multiple piston assembly is configured to be in a closed position while a pressure differential is above a certain threshold and to be in an open position while the pressure differential is below said certain threshold. While in the open position, a portion of the air in the duct system is released.

Abstract: The post driver with limited movement floating post anvil does not rely heavily upon the skill of the operator to efficiently drive posts. The post anvil is allowed to move up and down in relation to the driver, but its movement is limited by both lower and upper fixed barriers. Since the movement is limited, the operator can position the driver upon the post allowing the full weight of the driver framework/carrier machine to rest upon the post. The post would push the floating post anvil upward only to the point at which the upper fixed barrier prevents further upward movement of the floating post anvil. Thus, once the floating post anvil abuts the upper fixed barrier, substantially the entire weight of the post driver is resting on the post.

Abstract: The post driver machine includes a housing, inside of which is a weight which can be lifted by a chain being rotated around a generally elliptical path by a powered sprocket. A catch mechanism is affixed to the chain, and can engage with a weight catch attached to the weight. However, when there is not a post positioned within the post driver, the weight rests at a position too low the weight catch to engage with the catch mechanism. Upon properly inserting a post into the post driver, the post presses upwardly on the weight until the weight catch engages with the catch mechanism to lift the weight.

Abstract: A grapple mechanism is connected to a post driver on one side, rather than in the front of the post driver. The grapple connects to the post driver via a hinge which allows substantially 90 degrees of rotation between a horizontal position for picking up posts, and a vertical position for driving the post into the ground. A spring or other biasing mechanism preferably biases the grapple mechanism toward its horizontal position. However, the spring is preferably not so strong as to hold the grapple mechanism in the horizontal position even when a post is grappled. Preferably, the weight of a grappled post is sufficient to overcome the spring, causing the grapple mechanism to pivot about the hinge and into the vertical position. The grapple mechanism is therefore preferably sized, shaped and weighted so as to swing to a substantially vertical position when a post is grappled and lifted.