Abstract: This invention relates to a clamping device and more particularly to a clamping device which can be attached to articles such as patio chairs to mount a holder for umbrellas and the like in a variety of positions. The device comprises a main body including a barrel and a first clamping arm extending laterally in one direction from one end of said barrel, a second clamping arm pivotally mounted at the other end of said barrel and adapted to cooperate with the first clamping arm to engage an article upon which the clamping device is to be mounted, a holder extending laterally from said one end of said barrel in a direction other than said one direction, means for mounting said holder on said barrel to provide a position permitting pivotal movement and a position in which the holder is locked, spring means within the barrel acting to bias the mounting means to a locked position while permitting movement of the mounting means to the position permitting pivotal movement.