Blocking arrangement of elevating device for carpentry work

A blocking arrangement of an elevating device for carpentry work, wherein the elevating device comprising a platform and four threaded stems extending downwardly from an underside of the platform, each of the threaded stems having a threaded member a chain wheel screwed thereon, the threaded members and the chain wheels being positioned at four corners of a elevating table so as to rigidly clamp the elevating table therebetween, a chain being trained about the four chain wheels, wherein when the chain rotates, the chain wheels are driven to rotate simultaneously so as to drive the respective the threaded members to rotate by means of the inner threads thereof in order to elevate the elevating table up and down, wherein a brake wheel is provided below the chain wheel of one of the threaded stems in such a manner that the brake wheel and the respective threaded stem are able to be rotate simultaneously, wherein a stop block is provided beneath the elevating table and positioned with respect to the brake wheel, the stop block having an end connected with a longitudinal eccentric axle which has a top end rotatably pivoted to the elevating table, an eccentric portion being formed at a bottom end of the eccentric axle, the stop block having an oval hole and a bolt being extended through the oval hole, wherein an end of the bolt is blocked against the stop block to prevent dropping down while a top end of the bolt is affixed to the elevating table, wherein when the eccentric axle rotates an angle clockwise or counter-clockwise, the stop block is able to be moved to block against or away from the brake wheel, so as to render the threaded member and the chain wheel on the respective threaded stem being blocked from any movement, in order to prevent the threaded members and the chain wheels of the threaded stems from rotation to ensure elevating table to be positioned at a predetermined height being adjusted.