Swimming pool

A swimming pool having a liquid tight permanent bottom and side walls and a horizontal auxiliary vertically adjustable bottom positioned above the permanent bottom, having means for raising and lowering the said auxiliary bottom relative to the permanent bottom, comprising;

• a. the auxiliary bottom being of a size slightly less in dimension than the permanent bottom to enable the auxiliary bottom to be moved vertically within and adjacent the inner surface of the side walls of the pool;
• b. the means for raising and lowering the auxiliary bottom comprising a pair of elongated vertically arranged hinge supports positioned at two opposite sides of the pool, one pair of supports positioned one at each side of the pool and between the auxiliary bottom and the permanent bottom;
• c. each pair of supports being hinged at a point adjacent their centers;
• d. roller means fixed to the lower and upper ends of each of the hinged supports;
• e. a pair of tracks positioned over and along the under surface of the auxiliary bottom and over the upper surface of the permanent bottom extending in a plane with the hinged supports for receiving the said rollers, the length of the tracks being substantially the length of the under surface of the auxiliary bottom;
• f. means for moving the rollers along the tracks comprising a pair of threaded blocks connected to the lower ends of each of the hinged supports, including a shaft extending substantially the full length of the pool in a plane parallel with the hinged supports, having right and left hand threads on its opposite ends for threadedly engaging one of the said blocks at each end of the shaft.
• g. means positioned outside the pool for rotating the shaft in either direction;
• h. perpendicular stationary locking means spaced over the edge of the pool for fixing the selected positions of the auxiliary bottom, said stationary locking means having projections extending horizontally therefrom for engaging the underside of the auxiliary bottom, side stationary locking means being rotatable in a horizontal plane to an angle of at least 45.degree. for moving the horizontal projections in and out of engaging position with the auxiliary bottom for locking the same in position when in one position and out of locking position when in another position.