Portable friction welder

Abstract

A portable friction welder that applies direct axial load to the workpieces via a rotating variable pressure hydraulic cylinder placed between the workpieces and a rotational device. The portable friction welder includes an interchangeable adapter configured to receive a fitting for a first workpiece, a variable pressure hydraulic cylinder with a front end and a rear end, and a rotational device positioned behind the rear end of the pressurizing device. The friction welder is configured to be driven by the rotational device, to be interconnected to a clamp assembly holding a second workpiece, and to effect a friction weld to first and second workpieces. The portable friction welder also includes a bearing housing, thrusts bearings, and a thrust collar. Spring washers may be installed in the front end of the hydraulic cylinder to maintain axial load across the bearing housing. An interchangeable adapter is removably connected with the thrust collar.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention generally relates to friction welding and, more particularly, to a portable friction welder for welding first and second workpieces together that applies direct axial load to the workpieces via a rotating variable pressure hydraulic cylinder placed between the workpieces and a rotational device. [0003] 2. Description of the Related Art [0004] Friction welding is a process that welds metal or thermoplastics in which two members are joined by rubbing the mated parts under pressure. Heat is generated by direct conversion of mechanical energy to thermal energy at the interface of the mated parts, without application of electrical energy or heat from other sources. The weld is made by holding a non-rotating part in contact with a rotating one under constant or gradually decreasing pressure, until the interface reaches a certain temperature, e.g., forging temperature for metal parts. Rotation is then...

AI Technical Summary

Benefits of technology

"The present invention is a portable friction welder that can be used to weld workpieces together by applying direct axial load. The friction welder includes a rotating variable pressure hydraulic cylinder, a thrust collar, and a clamp assembly. It can be easily driven by a rotational device and interconnected to a second workpiece for friction welding. The friction weld can be maintained for a predetermined amount of time and the clamp assembly can be easily removed from the welded workpieces. The portable friction welder is affordable, reliable, and effective in achieving its intended purposes."

Problems solved by technology

Constraints in the choice of workpieces that may be joined, the need to have a threaded first workpiece to join to the bored and tapped second workpiece, extreme care needed to assure the initial drill step does not penetrate too far and go into the pressure or hazardous area and cause a safety and environmental issue, and sufficient remaining wall thickness after drilling and prior to tapping,. proper thread sealing are some problems associated with the drill and tap technique.

However, friction welding has not been successfully implemented due, in part, to two major weaknesses.

First, the indirect means of applying force with the indirect workpiece-actuator-motor configuration does not supply the necessary amount of force to provide a sufficiently strong weld, particularly when dealing with curved surfaces.

Second, the portion of the second workpiece in contact with flammable materials may reach high surface temperatures resulting in ignition of the flammable materials.

However, arc welding is not performed on small fittings (e.g., two inches and lower) because arc welding occurs at temperatures significantly higher than friction welding, and degrades small fittings or base metals due to heat concentration on the small fittings.

Friction welding is currently performed with stationary friction welders that are large and are unable to be utilized on live systems.

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