Abstract: A height-adjustable work surface assembly includes a base portion and a work portion, and may include a gas spring, an actuation mechanism, a rack, and a pinion. The work portion is supported by the base portion for translation along a first path of motion. The gas spring is actuatable between a locked position and an unlocked position, and is operable to apply a force on the work portion in the unlocked position to urge the work portion along the first path of motion. The actuation mechanism is coupled to the gas spring to move the gas spring from the locked to the unlocked position. The rack is supported by the work portion or the base portion and includes a first plurality of teeth. The pinion is supported by the other of the work portion and the base portion and includes a second plurality of teeth.

Abstract: A safety latch for supporting a post in a post driver while the post is being driven into the ground. A post-engaging roller is mounted on a lever arm that is pivotally attached to the post driver and moveable between a released position for positioning of a post in the post driver and a working position where the roller is in supporting engagement with the post. A spring biases the roller to maintain supporting engagement with the post while it is driven. In a preferred embodiment, the spring is part of an over-center device for biasing the safety latch to both the released and working positions depending on which side of center the lever arm is positioned.