An apparatus for providing an adjustable height top edge of an inclined plane includes a generally planar inclined plane that is pivotally attached at a bottom end thereof at a pivot axis to a first end of a first base member and to a first end of a spaced-apart second base member. The first and second base members are parallel with respect to each other and include a first slot and a second slot, respectively. A slide bar having a first bar end and an opposite second bar end is disposed between the first base member and the second base member and is secured in position by a first screw that passes through the first slot and by a second screw that passes through the second slot. The top edge of the inclined plane is urged to a desired height and is retained in position by friction. The slide bar is urged toward the pivot axis until it is in contact with opposite sides of the inclined plane. The first and second screws are tightened to secure the inclined plane in position.
