Abstract: An extension tube in a vacuum cleaner includes a lower extension tube for drawing dust laden air through an air suction nozzle fitted at one end, an upper extension tube having one end connected to a hand grip extended to a body of the vacuum cleaner for passing the dust laden air drawn through the lower extension tube, a joint part connected to the other ends of the lower extension tube and the upper extension tube for making the lower extension tube and the upper extension tube foldable relative to each other to a preset angle, and a locking arrangement for locking the joint part to fold/unfold the joint part selectively, thereby permitting a user to fold the upper and lower extension tubes, and to carry out an easy cleaning of even an underside of a sofa or a bed without bending the user's body, thereby enhancing the user's convenience.

Abstract: A thread for expandable downhole tubular connections is disclosed. It features a locking pattern on the pin and box, which engages upon expansion of the connection. The locking pattern compensates for longitudinal shrinkage away from a torque shoulder, as a result of expansion. A resilient seal can be incorporated into the design with pin to box clearance disappearing around the seal as a result of expansion. Resilient seals can be used in tandem to trap atmospheric pressure between them. The wellbore hydrostatic pressure helps engage the locking feature by pushing the box into the pin, helped by the trapped low pressure between the seals.