Hydropneumatic cable tensioner
AssigneeRetsco, Inc.
InventorLarry B. Jordan
Life of this patent
Estimating the term…
Abstract
A hydropneumatic cable tensioner is comprised of an enclosed cylinder featuring a plurality of annular chambers. A fixed cable sheave is mounted to one end of the cylinder. A movable cable sheave is mounted to a piston rod connected to a piston which reciprocates in the innermost or piston bore chamber of the cylinder. Regulated compressed gas is connected to the outer chamber of the cylinder thereby exerting high pressure forces on oil found in the middle or high pressure oil chamber of the cylinder. Pressurized oil forces a piston to move outwardly thereby increasing the distance between the two sheaves and tensioning a cable. Restriction means within the piston bore chamber regulate movement of the piston and prevent uncontrolled acceleration should a cable failure occur.
Claims8
A hydropneumatic cable tensioner comprising:
- a base;
- a cylinder mounted on said base;
- a first enclosure means for enclosing one end of said cylinder;
- a first cable sheave mounted to said first enclosure means;
- a piston bore chamber within said cylinder;
- a piston reciprocable in said piston bore chamber comprising a conical frustum shaped support bushing fitted onto a reduced diameter piston mounting section and butted up to a shoulder on said piston rod;
- a piston seal bushing fitted over said reduced diameter piston moving section abutting said support bushing and covering a plurality of grooves on said reduced diameter piston mounting section of said piston rod;
- and securing means mounted in another of said grooves on said reduced diameter piston mounting section for retaining a piston sealing means onto an axial lip of said seal bushing and for retaining said seal bushing against said support bushing;
- a piston rod connected to said piston comprising a reduced diameter piston mounting section thereby forming a shoulder on said piston rod;
- and a plurality of circumferential grooves defined by said reduced diameter piston mounting section;
- a second enclosure means for enclosing the other end of said cylinder said second enclosure means adapted to permit said piston rod to extend therethrough;
- a second cable sheave mounted on the opposite end of said piston rod from where said piston is attached;
- a low pressure subchamber within said piston bore chamber;
- a high pressure oil chamber surrounding said piston bore chamber, said high pressure oil chamber ported to permit flow between said piston bore chamber and said high pressure oil chamber;
- an accumulator chamber within a cylinder surrounding said high pressure oil chamber said accumulator chamber ported to permit flow between said high pressure oil chamber and said accumulator chamber;
- piston sealing means for preventing oil from the high pressure oil chamber from entering said low pressure subchamber comprising a plurality of packing rings mounted on said lip of said seal bushing;
- restriction means secured within said low pressure subchamber for controlling fluid flow within said piston bore thereby limiting piston velocity in the event of a sudden loss of cable tension and for guiding said piston rod in its reciprocal movements comprising an annular ring fitted within said low pressure subchamber having an inner face positioned around said piston rod;
- a small gap defined as the space between said annular ring and said piston rod whereupon movement of said piston, fluid flow is restricted within said low pressure subchamber resulting in regulation of piston velocity;
- containment means within said piston bore for containing an initial charge of gas, and oil displaced through said restriction means;
- and
- means for introducing regulated compressed gas to said accumulator chamber to pressurize said accumulator chamber wherein oil in said high pressure oil chamber is also pressurized thereby urging said piston to move outwardly which in turn urges said piston rod connected thereto to move outwardly through said second enclosure means thereby tensioning the cable.
Dependencies are inferred from the claim text.