Vibrodriver apparatus

In combination, a vibrodriver for sinking or extracting a vertically elongated element of substantially uniform horizontal cross-section into or from the ground, said element being one of plural such elements arrayed in a line, said vibrodriver comprising at least three parallel eccentrics, means mounting said eccentrics for rotation about horizontal axes, at least two eccentrics or portion thereof being situated on a different sides of said element, means releasably clamping said vibrodriver on said element, so that said element is a clamped element, and means to rotate said eccentrics, whereby said clamped element is vibratorily sunk into or extracted from the ground, said clamped element having a maximum width along said line of elements, said at least two eccentrics or portion thereof having enlarged effective width dimensions exceeding the corresponding effective width dimension of a third of said eccentrics, said enlarged effective width dimensions being accommodated at zones spaced laterally from the clamped element, said vibrodriver being narrower than said clamped element at the zone adjacent said clamped element so that the vibrodriver has increased power due to the enlarged effective width dimensions yet will be clear of elements adjacent the clamped element.