Provided is a high-pressure fuel injection pipe with a connection head which achieves an improvement in outer-surface cleanliness and prevention of a decrease in axial force and fastening strength. The pipe having, at a connection end of a narrow-diameter thick-wall steel pipe having a rust-inhibiting coating applied to an outer surface of the pipe, the connection head composed of a spherically-shaped seat surface, an annular flange, and a conical surface and having an outside peripheral surface forming formed into seat surface in a truncated conical shape or truncated arc shape for a mating seat; and a washer fitting in a neck lower part of the connection head and having a rust-inhibiting coating applied to an outer surface of the washer, wherein a contact part between the neck lower part of the connection head and an end part of the washer has a metal-to-metal contact structure without having the rust-inhibiting coating.

A sleeve, a cylindrical member for connecting a tube to a tubular body of a fitting, includes a first peripheral wall end portion facing a peripheral wall end portion of the tubular body, and a second peripheral wall end portion pressed into an open end of the tube. The first peripheral wall end portion includes either an annular protrusion or groove. The annular protrusion is pressed into an annular groove in the peripheral wall end portion of the tubular body. The annular groove allows an annular protrusion axially projecting from the peripheral wall end portion of the tubular body to be pressed thereinto. The second peripheral wall end portion includes a bulge portion to expand the diameter of the open end of the tube. An outer periphery of the first peripheral wall end portion includes a flange to axially face the peripheral wall end portion of the tubular body.

An axial force measurement device includes a frame, a tightening actuation unit that performs tightening operation upon a screw type tube fitting installed upon a tube upon which is formed an annular portion projecting in the radially outward direction from the tube, a testing member, and a mating member holding unit that holds the testing member into which the tube fitting is screwed and that is coupled to the tube. The tightening actuation unit and the mating member holding unit are provided to the frame in line along the direction of a reference axis that extends in the direction of the center line of the tube fitting and the tube axis of the tube. The testing member has a first part that engages with the tube fitting, and a second part against which the annular portion of the tube is pressed.

An assembly includes a first tube. The first tube includes a first end configured to receive a second tube. The second tube includes a first end configured to slidably translate into the first end of the first tube and to receive an insert. The insert is configured to be disposed within a first portion of the second tube that is near the first end of the second tube. The first tube, the second tube, and the insert form a seal. The coefficient of thermal expansion (CTE) of the first tube is similar to the CTE of the insert and different from the CTE of the second tube.

A method for manufacturing a tube fitting includes steps of: preparing the tube fitting; and forming a resin coating layer upon a coated region provided upon the surface of the tube fitting. Forming the resin coating layer includes: dipping the tube fitting into a coating material that includes as components a polyethylene based substance, a lubricant, and solid particles and having viscosity within a range of 4.24 to 5.27 mPa.Math.s at 25? C., and adhering the coating material to the coated region; and, drying the coating material which is adhered to the coated region of the tube fitting. In the dipping step, the mass per unit area w is controlled within a range 0.79<w<10.07 by dipping the tube fitting while regulating a temperature of the coating material within a range of 30? C. to 40? C.

A flare-type brake line assembly includes (a) a brake tube having a flare with a first sealing surface, (b) a brake component having a port with a second sealing surface and (c) a tube nut to secure the brake tube and brake component together. At least one of the two sealing surfaces is treated to increase the coefficient of friction between those surfaces. A related method is also disclosed.

A tube fitting includes: a zinc-based plated layer; and a resin coating layer that is positioned at an outermost surface at an outer side of the zinc-based plated layer and includes a polyethylene substance, a lubricant, and solid particles. When a fitting average plating thickness t relating to the thickness of the zinc-based plated layer is defined, 2.1<t<19.7 is true.

A pipe connection includes a connection body, a nut which can be screwed onto or into the latter and which has a conical bore which widens toward the connection body, and a pipe guided through a bore in the nut and having an outwardly projecting formation with two clamping faces. A first clamping face is parallel to the end face of the connection body and is supported on the connection body at least in certain regions when the pipe connection is in the clamped state, and the second clamping face is cone-shaped in a manner corresponding to the conical bore in the nut and is supported in the conical bore in the nut. The connection body has a radially encircling cutout by which a receiving space is formed for a sealing ring that is delimited by the first clamping face and has a polygonal, symmetrical cross section.

A flexible joint including: a socket including a front end portion provided with O-ring grooves, and a male threaded portion extending outward radially, circumferentially, and stepwisely from the front end portion with male threads formed thereon; a nut including an engaging portion engaged with an outer circumferential surface of the front end portion, and a female threaded portion extending stepwisely from the engaging portion and engaged with the male threaded portion; a sprinkler flexible tube communicating with an inner circumference of the socket, and having an enlarged portion inserted between the front end portion of the socket and the engaging portion of the nut, and a leak-proof portion or a double bent portion bent outward from an end of the enlarged portion; and O-rings fitted over the O-ring grooves, whereby the enlarged portion presses the O-rings to come into close contact with each other, thereby preventing leakage.

A male swivel hose coupling includes a hollow tail piece having a receiving portion and a stem and a hollow collar having a threaded portion. The collar is received over the receiving portion and is freely rotatable with respect to the receiving portion. The receiving portion of the tailpiece includes a rim and a shoulder, and the collar includes a lip and a shoulder. The rim of the receiving portion forms a first stopping surface for engaging the lip and the shoulder of the receiving portion forms a second stopping surface for engaging the shoulder of the collar.