Abstract: A riser tensioner system 10 is provided for use on offshore oil drilling platforms to support a riser 12 relative to a floating platform. The riser tensioner system 10 uses either elastomeric pads 32 or helical metal springs 100 as an energy absorbing medium, rather than hydraulic, or pneumatic systems. The elastomeric pads 32 or helical metal springs 100 are maintained in compression within a shock absorber housing 76 by a plunger 70 which is compressed by the weight of the riser 12. If the riser tensioner system 10 is arranged to place the shock absorber 20 in tension, the shock absorber plunger 70 is inverted in the housing 76 to maintain the elastomeric pads 32 or helical metal springs 100 in compression. To achieve varied response characteristics, nested inner and outer elastomeric pads 50, 52 or compression springs 102, 106 are arranged to act together.

Abstract: A sucker rod coupling 10 having a high ultimate tensile strength, resistance to corrosion, and resistance to surface cracking arising out of a method of making the sucker rod coupling 10, which employs a five-step process of forming a coupling 10. First, a hollow cylindrical core 12 from a heat treatable steel is formed. Second, a thin coating 18 of metallic alloy is applied to the outer surface of the core 12. Third, the core 12 is heat treated. Fourth, threads 20 are partially cut in the inner surface of the core 12. Fifth, the threads 20 are cold worked to transform the partially cut threads 20 into finished threads 20 and to place the thread roots 22 in compression.

Abstract: To overcome problems with the pistons of an energy cell rotating and becoming misaligned with one another in response to the forces exerted on the energy cell by a riser tensioner system, a two-piece elastomeric spring is disposed about each piston to create an elastomeric strut. Each piece of the spring is composed of a plurality of elastomeric layers separated by relatively inelastic spacers. These springs facilitate the longitudinally flexing of the elastomeric strut while substantially preventing rotation and misalignment in the radial direction.

Abstract: A high-capacity elastomeric combination journal-thrust bearing comprises at least one encapsulated lobe. The encapsulated lobe comprises an outer tubular member having a first ring joined along substantially all of its outer periphery to the inner periphery of the outer tubular member at a first end and having a second ring joined along substantially all of its outer periphery to the inner periphery of the outer tubular member at a second end. The encapsulated lobe further comprises an inner tubular member having the same longitudinal axis of the outer tubular member, and having a third ring joined along substantially all of its inner periphery to the outer periphery of the inner tubular member, spaced between the first and second rings. An elastomer separates and joins the rings to each other and to the tubular members, and the tubular members to each other. As the radial distance from the longitudinal axis increases, the thickness of the elastomer increases.