Patent ID: 9375837
Filing Date: 2016-06-28
CPC Classification: A47F,B25J,F16M,F21V,G01B,Y10T

Claim Text:
1. An arm structure having a parallel linkage formed by connecting a fixed portion and a movable portion via two parallel arms, a first arm and a second arm parallel to the first arm, each arm having rotating shafts at both ends thereof, the movable portion supporting an object and tiltable about the respective rotating shafts of the first arm and the second arm with respect to a gravity direction, the arm structure comprising: a spring expanding and contracting linearly along the first arm; and a stopper fixed relative to the second arm and receiving one end of the spring, the stopper including a planar surface perpendicular to a longitudinal axis of the second arm, the planar surface including an elongated hole, the first arm passing through the hole and one end of the spring resting on the planar surface of the stopper, the stopper comprising an L-shaped member, one leg of the L-shaped member comprising the planar surface, the planar surface defining a plate, the other leg of the L-shaped member secured to the second arm, the one end of the spring directly contacting a periphery of the elongated hole; wherein, when the movable portion is tilted, the spring is expanded/contracted due to a relative displacement of the stopper with respect to the first arm so as to generate a repulsive force in an anti-tilting direction.