Patent ID: 7018386

Claim:
A medical stand apparatus comprising: a base set on the floor, the base having a post installed on the base, the post being horizontally articulated about an axis of rotation oriented in a predetermined direction with respect to the base, the post being provided with upper and lower articulations; a parallel link mechanism supported by the upper articulation, the parallel link having a pair of parallel longitudinal links and a pair of lateral links; a support arm extending from the upper lateral link of the parallel link mechanism, a front end of the support arm supporting an end link; a crank articulated about a first articulation of the parallel link mechanism, the first articulation serving as a start point of the support arm; a longitudinal sub-link parallel with the longitudinal links, a lower end of the longitudinal sub-link being articulated at a front end of a horizontal first upper protrusion formed on the post, one of the longitudinal links adjacent to the support arm, the crank, the longitudinal sub-link, and the first upper protrusion forming a first auxiliary parallel link; a lateral sub-link parallel with the support arm, the lateral sub-link cooperatively moving in response to position of the longitudinal sub-link through the crank, an upper end of the end link being articulated at a first end or the lateral sub-link opposite the crank, the support arm, the upper end of the end link, the lateral sub-link, and the crank forming a second auxiliary parallel link; an interlocked longitudinal link always parallel with the longitudinal links, an upper end of the interlocked longitudinal link being articulated at the lower articulation, a lower end of the interlocked longitudinal link being articulated at a first end of an interlocked lateral link; a second upper protrusion formed at a lower end of the longitudinal links, a front end of the second upper protrusion being connected to a front end of a lower protrusion formed at an upper end of the interlocked longitudinal link through an interlocked longitudinal sub-link, the orientation and length of a straight line between upper and lower articulations of the interlocked longitudinal sub-link being equal to those of a straight line between the upper and lower articulations; a weight link connecting an end of the lower lateral link of the parallel link mechanism opposite the medical equipment and a second end of the interlocked lateral link, the weight link being parallel with a straight line between the upper articulation and the first end of the interlocked lateral link; and a counterweight arranged at the second end of the interlocked lateral link, the counterweight cooperatively moving toward and away from the lower articulation in response to movement of the medical equipment about the upper articulation, the weight of the counterweight acting on the parallel link mechanism to keep the medical equipment at an optional spatial position.