Support prop
AssigneeDorbyl Limited
InventorsMichael S. Bacon, Andrew T. Greenwood, Ivan Terblanche, Allan W. Hillier, Anthony J.S. Spearing
Life of this patent
Estimating the term…
Abstract
The support prop consists of an outer robe (12) with an open flared mouth (14) into which a plunger (16) projects. A deforming ring (18) in use engages the plunger and is initially located within the flared mouth of the outer tube. A chamber (26) is provided within the prop into which fluid under pressure can be introduced through an inlet (28) to the chamber to locate the prop between two surfaces by displacing the plunger relative to the outer tube. A seal (24) is located within the chamber to prevent the fluid from escaping between the plunger and the bore of the outer tube.
Claims16
A support prop including:
- an outer tube with an open flared mouth;
- a plunger which is telescopically movable in and out of the outer tube;
- deforming means in the flared mouth (14) of the outer tube about the plunger which is adapted to permit axial sliding movement of the plunger relative to the outer tube and to grip and be pressed with the plunger into the outer tube under load to cause lateral outward deformation of the outer tube by which the load on the prop is yieldably resisted;
- characterized in that:
- the prop includes friction reducing means on the inner wall of the outer tube;
- a chamber in the outer tube;
- an inlet for introducing fluid under pressure in the chamber to cause sliding movement of the plunger axially relative to the tube;
- and
- a seal arrangement in the chamber to limit fluid escape from the chamber.
A method of yieldably supporting a load over a surface by means of a support prop having:
- an outer tube with an open flared mouth;
- and a plunger which is telescopically movable in and out of the outer tube through its flared mouth;
- characterized in that the method includes the steps of:
- introducing fluid under pressure into a chamber within the support prop to locate the prop between the load and surface by axially displacing the plunger outwardly from the outer tube forcing deforming means into the flared mouth of the outer tube to engage the plunger and set the yield load of the prop whilst the fluid is under pressure within the chamber;
- and
- allowing the fluid to drain from the chamber to enable the load across the prop to press the plunger and deforming means into the outer tube to cause the deforming means to deform the outer tube laterally outwardly yieldably to resist the load on the prop.
Dependencies are inferred from the claim text.