Abstract: A mounting system for plastic siding comprises an elongated nailing strip from which a siding panel is suspended by means of interlocking channels which permit longitudinal relative movement resulting from differential thermal expansion or contraction. A predetermined amount of horizontal overlap of adjacent panels is assured by the provision of a notch adjacent each end of the panel, which notch is intended to be vertically aligned with the end of the adjacent panel. The same notches provide a guide for centering the nailing strip on its associated panel. Unintended disassembly of each strip-panel pair is presented by dimple-like deformations near the end of each strip cahnnel, which function to limit the longitudinal travel of the associated panel channel therein.

Abstract: A pavement breaking apparatus having variable impact force for fracturing concrete to a size and pattern specification without distorting the material. The apparatus includes at least one spring pack connected between a leaf spring housing and an impact tool holder. The housing is connected to a vehicle for pivotal movement about a transverse horizontal axis. Further, the housing is connected to the vehicle for movement about a vertical axis thereby permitting lateral swinging movement of the spring pack and tool holder. The spring pack includes a plurality of stacked leaf springs with a centrally located main leaf spring extending full length between the housing and tool holder. First and second groups of leaf springs having variable lengths are stacked together on opposite sides of the main spring. The spring pack further includes third and fourth groups of leaf springs positioned on opposite sides of the main spring between the main spring and the first and second groups of springs.