Abstract: An adjustable device for adjusting a length of a foldable table leg. The adjustable device covers the upper side of a support frame and comprises a mounting plate, a control rod and an auxiliary spring. The center of the spring resists against the control rod. An adjusting rod is located on the bottom of the support frame. Adjusting holes are formed along the inner bottom of the adjusting rod. Therefore, when one end of the control rod is pressed down and after a hook end of the control rod lifts upwards, the hook of the control rod is disengaged from the adjusting hole of the adjusting rod, enabling the adjusting rod to be adjusted to have an appropriate length. After the control rod is released, the restoring force of the spring causes the control rod to fit into another adjusting hole to accommodate uneven floor surface.

Abstract: A coupling structure includes two couplings joined back-to-back as a unit by means of a bolt, each coupling consisting of a box-like base, a pair of non-skid blocks disposed within the base, a cover pivotally connected to the base, a press plate and a couple of adjusting screw bolts. The base is provided with notches in its two longitudinal walls for supporting a tube. The non-skid blocks are respectively provided with upper non-skid surfaces for urging against a lower portion of the tube. After the tube is mounted within the base, the cover is locked in place by means of the screw bolts which join the press plate to the cover and pass through corresponding holes in the base and the non-skid blocks to secure the tube.