Steel prop capable of bearing bidirectional applied force

Steel prop capable of bearing bidirectional applied force, comprising:

• an outer tube, inner wall of top end of the outer tube being formed with a conic face having inward tapered inner diameter;
• an inner tube, the body of the inner tube being formed with continuous thread, a bottom end of the inner tube being back and forth slidably nested in the outer tube;
• two clamping members each having a body, an inner circumferential face of the body being semicircular and formed with several transverse thread sections, a lift handle being disposed on outer circumferential face of the body of each clamping member, a projecting pressed section having a certain width being formed under the lift handle, two lateral sides of the clamping members being connected, whereby the clamping members can be moved toward or away from each other within a certain distance without departure;
• and
• a retaining member, having two inward projecting engaging lips spaced apart at equal intervals on a section through an inner circumference at a top of the retaining member creating two equal recesses between the engaging lips on the section through the inner circumferences, a bottom face of the engaging lips being formed with a sloped pressing face, the retaining member being rotatably fitted around top end of the outer tube, a bottom edge of the retaining member being stopped by the top end of the outer tube, so that the retaining member is prevented from departing from the top end of the outer tube, lower halves of the bodies of the clamping members being received in the retaining member, in normal state, the bottom ends of the clamping members being positioned on the conic face and the pressed sections being positioned under the engaging lips of the retaining member, the lift handles being positioned outside the retaining member for manual operation, wherein when rotating the retaining member in a first direction, the sloped pressing faces of the engaging lips press against the pressed sections of the clamping members and tightly engage the retaining member to the clamping members, wherein the two clamping members are guided by the conic face to mate with each other and the thread sections of the clamping members mesh with the thread of the inner tube, the bottom edge of the retaining member being upward engaged with the top end of the outer tube, wherein when rotating the retaining member in a second direction, the engaging lips are disengaged from the pressed sections, and the pressed sections are aligned with the recesses and the clamping members are disengaged from the retaining member to release the inner tube from the clamping members, wherein when the clamping members are engaged by the retaining member, the steel prop is able to bear both axial pressure and axial pulling force.