Patent ID: 7234847

Claim:
A projector comprising: a telescopic support column installed on a base, a lifting and lowering device provided inside said support column, a lighting system provided on a distal end of said support column, and a power supply unit for supplying power to said lighting system, wherein said support column is constituted by loosely fitting a base support column fixed to a base to an upper support column comprising a plurality of support columns whose outer diameters are made smaller in ascending order relative to said base support column, said plurality of support columns constituting said upper support column are loosely and sequentially fitted into each other in a vertically movable manner and in a rotatable manner in conjunction with one another, and wherein said upper support column comprises second and third support columns, said lifting and lowering device is equipped with a biasing means that is fitted loosely into an inside of said second support column in a vertically movable manner and biases said support column in its extending direction, a lower end of said biasing means is fixed to an inner bottom of said base support column together with an inner race of a bearing provided thereabove, a pulley is provided on an upper end of said biasing means, and a wire is wound around said pulley, one end of said wire being fixed to a receiving portion provided on an outer race of said bearing, while the other end of said wire being fixed to a lower portion of said third support column.