Patent ID: 8038108

Claim:
An apparatus for supporting a medical instrument, the apparatus comprising: a support column configured to be placed in one of a floor, a ceiling, a medical trolley and a bed; an arm supported by the support column and having a first end provided with a support portion configured to support a medical instrument and a second end, the arm being configured to move the support portion in horizontal directions and vertical directions relative to the support column; a position changing member provided at the second end of the arm and configured to move in accordance with movement of the support portion to a position corresponding to a position to which the support portion has been moved; a vertical guide portion provided at the support column; and a counterweight system including: a connecting slide connected to the vertical guide portion so as to be immovable in the horizontal directions and movable in the vertical directions relative to the support column, a weight connecting portion connected to the position changing member such that the position changing member is immovable in the vertical directions and movable in the horizontal directions relative to the weight connecting portion, an intermediate portion connecting the connecting slide and the weight connecting portion to each other, and a force generating portion configured to generate a vertically downward force to be exerted on the position changing member via at least the weight connecting portion of the connecting slide, the weight connecting portion and the intermediate portion, wherein the position changing member is configured to move in the horizontal directions relative to the counterweight system and to move in the vertical directions together with the counterweight system, and to keep a balanced state between the medical instrument supported by the support portion and the counterweight system when the first end of the arm is moved in the horizontal directions and the vertical directions.