In a threaded connection of a two-step thread construction including intermediate shoulder surfaces, a break is prevented near the intermediate critical cross sections upon application of a tensile load, and the intermediate shoulder surfaces are easier to create, thus improving productivity. The outer periphery portion of a pin located between an intermediate shoulder surface of the pin and a second male thread is provided with a circumferential groove including a curved surface smoothly contiguous to the intermediate shoulder surface, thereby mitigating plastic strains generated near the pin intermediate critical cross section PICCS. The inner periphery portion of a box located between an intermediate shoulder surface of the box and a first female thread is provided with a circumferential groove including a curved surface smoothly contiguous to the intermediate shoulder surface, thereby mitigating plastic strains generated near a box intermediate critical cross section BICCS.

The present invention provides an extension member for coupling with a quick coupler key. The extension member includes: a first member; a second member; a handle; and a third member. Methods of using the extension member for coupling with a pipe and a quick coupler key, which is coupled to a quick coupler assembly are also provided.

A threaded joint with excellent tensile strength, comprising: a pin having an externally threaded part comprising a first and second externally threaded sections across a step on an outer periphery on a distal-end side of a first steel pipe or tube; and a box having an internally threaded part comprising a first and second internally threaded sections across the step on an inner periphery on a distal-end side of a second steel pipe or tube, the externally threaded part being screwed to the internally threaded part to join the pin and the box. The threaded joint has a first and second thread sequence with lengths L1 and L2, respectively, and cross-sectional areas P1, P2, B1, and B2 at end positions 4, 5, 6, and 7, respectively, satisfying Formulas (1) and (2): (P2, B2).sub.min≤P1/{L1/(L1+L2)}(1) and (P2, B2).sub.min≤B1/{L2/(L1+L2)}(2), where (P2, B2).sub.min represents P2 or B2, whichever is smaller.

A pipe-fitting device according to the present invention includes a fitting body and a flare packing. The fitting body has a first end portion with an inner threaded portion, a second end portion, and a narrowest portion between the first end portion of the fitting body and the second end portion of the fitting body. The flare packing has a double plane surface having different inclination angles and is provided inside a cavity of the first end portion of the fitting body.

A threaded joint (200) provides for metal-to-metal sealing on the ends of concentrically positioned inner and outer tubes when joining the concentric tubes to a single tube (107). A threaded coupling (105) secures the inner and outer tubes and joins both tubes to a single tube. The threaded connection leverages metal-to-metal sealing on the ends of each tube. The inner tube (102) may differ in length from the outer tube (101) and contains a single thread (211) at its for receiving the threaded coupling. Threading the coupling onto the inner tube establishes four flexing metal-to-metal seals (209A-D) between the threaded joint components. The inner and outer tubes maintain contact at the internal shoulder (104) as a result of preloading. If the tubes are of varying thicknesses, a nut (407) is placed between the internal shoulder and the threaded coupling to preserve contact between the tubes at the internal shoulder.

A filter adaptor joins a canister filter to a hydraulic manifold block. The adaptor includes a hexagonal tool-receiving portion, an outflow passageway and one or more inflow passageways. The outlet flow passageway extends between opposed ends of the adaptor, and is used to direct filtered fluid from the filter to the manifold block. The inlet flow passageway(s) extend between the one end and a sealed region of the adaptor, and are used to direct fluid from the manifold block to the filter. The adaptor includes auxiliary ports formed in the tool-receiving portion that communicate with the inlet flow passageways and permit monitoring thereof.

A pipe-fitting device according to the present invention includes a fitting body, a fixing nut, and a collet. A first end of the fitting body is rotatably connected to an outer circumferential surface of a first pipe, and a second end of the fitting body surrounds an outer surface of a second pipe. A first end of the fixing nut is rotatably connected to an outer circumferential surface of the fitting body, and a second end of the fixing nut surrounds the outer surface of the second pipe. The collet is provided inside the fixing nut and presses the second pipe when the fixing nut is rotated and tightened. The collet includes a seating portion provided inside the fixing nut, a bending portion in which a bending groove is formed, a pressing portion which presses and seals the second pipe, and a protecting portion which protects the pressing portion.

In a threaded connection of a two-step thread construction including intermediate shoulder surfaces, a break is prevented near the intermediate critical cross sections upon application of a tensile load, and the intermediate shoulder surfaces are easier to create, thus improving productivity. The outer periphery portion of a pin located between an intermediate shoulder surface of the pin and a second male thread is provided with a circumferential groove including a curved surface smoothly contiguous to the intermediate shoulder surface, thereby mitigating plastic strains generated near the pin intermediate critical cross section PICCS. The inner periphery portion of a box located between an intermediate shoulder surface of the box and a first female thread is provided with a circumferential groove including a curved surface smoothly contiguous to the intermediate shoulder surface, thereby mitigating plastic strains generated near a box intermediate critical cross section BICCS.

A threaded connection for drilling tubulars includes a tubular box section having a sidewall. The box section has a tapered box portion of an inner surface of the sidewall between a first end and a second end. The tapered box portion has internal threads, a first torque shoulder on a first side of the tapered box portion, and a second shoulder on a second side of the tapered box portion. A threaded collar having internal collar threads is positioned between the second end and the second shoulder. A threaded insert having a tubular body with an inner surface and an outer surface having external insert threads is configured for threadably connecting to the internal collar threads. A direction of the internal threads of the tapered box portion is opposite to a direction of the internal collar threads and the external insert threads.

Technologies are described for devices and methods to couple a hose to another hose or apparatus. The device may comprise a first side with at least two barbed fittings, each configured to insert into a flexible hose to create a waterproof seal. A diameter of each barbed fitting may increase in size from a first end of the first side to a second end of the first side. The device may comprise a second side with at least two male fittings, each configured to threadly interact with threads of a female fitting to create a waterproof seal. A diameter of each two male fitting may increase in size from a first end of the second side to a second end of the second side. The device may comprise a separator rim attached to the second end of the first side and to the second end of the second side.