A hollow spring includes a steel tube in which the average of surface roughness is smaller than 10 m across the entire inner surface of the steel tube and/or compressive residual stress is given to the entire inner surface of the steel tube. The hollow spring may be manufactured by a step of polishing the inner surface of the steel tube by flowing a viscoelastic abrasive medium (200) within the tubular member (10), between a first opening (11) and a second opening (12) of the tubular member (10). The abrasive medium (200) may include a viscoelastic base material and a granular abrasive. The inner surface of the steel tube is polished evenly to reduce the surface roughness and/or is given compressive residual stress to increase the fatigue life of the hollow spring.

The invention relates to a blade bit of a pipe cleaning or opening device comprising a working part and a fastening part, that the working side of the working part of the blade bit has saw edged form, which has at least two, substantially sharp protrusions, which are substantially V-shaped.

The present disclosure is directed to a surfacing tool for repairing a sealing surface on a fitting. The surfacing tool is defined by a tool head and a tool head guide having an internal bore sized to receive the tool head. The tool head is includes a reverse flare working surface positioned at a first end thereof. A threaded element is positioned at one end of the tool head guide to threadingly receive a threaded flare fitting. The tool head being rotatable within the tool head guide while engaging and grinding the sealing surface on the fitting to a desired finish.

The present disclosure is directed to a surfacing tool for repairing a sealing surface on a fitting. The surfacing tool is defined by a tool head and a tool head guide having an internal bore sized to receive the tool head. The tool head is includes a reverse flare working surface positioned at a first end thereof. A threaded element is positioned at one end of the tool head guide to threadingly receive a threaded flare fitting. The tool head being rotatable within the tool head guide while engaging and grinding the sealing surface on the fitting to a desired finish.

A tire pre-conditioning system includes a first mandrel, a second mandrel spaced apart from the first mandrel, and a controller in communication with the first mandrel and the second mandrel. The first mandrel is fixedly attached to a first shaft and including a first tapered sidewall. The second mandrel is fixedly attached to a second shaft and including a second tapered sidewall. The controller is operable to axially move the first mandrel and the second mandrel toward one another until the first and second tapered sidewalls are opposing respective beads of a tire, and supply pressurized fluid into an internal cavity of the tire to inflate the tire. The inflating causing the beads to move relative to mandrels while contacting the opposing respective tapered sidewalls to burnish the beads of the tire.

To uniformly bring an abrasive into contact with a workpiece and to achieve desired surface roughness. A polishing tool sliding on a narrow part of the workpiece includes an abrasive retaining layer configured to allow an abrasive to be retained on a surface, and an elastic layer that is stacked on the abrasive retaining layer and is configured to press the abrasive retained in the abrasive retaining layer against the workpiece. The elastic layer is preferably elastically deformable over a sliding stroke of the polishing tool, and a driving unit that causes the polishing tool to slide on the workpiece is preferably connected to the polishing tool.

To uniformly bring an abrasive into contact with a workpiece and to achieve desired surface roughness. A polishing tool sliding on a narrow part of the workpiece includes an abrasive retaining layer configured to allow an abrasive to be retained on a surface, and an elastic layer that is stacked on the abrasive retaining layer and is configured to press the abrasive retained in the abrasive retaining layer against the workpiece. The elastic layer is preferably elastically deformable over a sliding stroke of the polishing tool, and a driving unit that causes the polishing tool to slide on the workpiece is preferably connected to the polishing tool.

The device is for cleaning the inner surface of a pipe. The device has a spindle arranged to be rotated and having a front end and a rear end between which a plurality of elastic metal blades are attached both in the rotation direction of the spindle and in the direction perpendicular to the rotation direction to clean the inner surface of the pipe. The blades have a shape that is curved at at least two points such that they curve at least once towards the circumferential direction of the spindle and at least once outwards from the circumferential direction of the spindle to prevent the device from getting stuck in uneven pipe systems.

The device is for cleaning the inner surface of a pipe. The device has a spindle arranged to be rotated and having a front end and a rear end between which a plurality of elastic metal blades are attached both in the rotation direction of the spindle and in the direction perpendicular to the rotation direction to clean the inner surface of the pipe. The blades have a shape that is curved at at least two points such that they curve at least once towards the circumferential direction of the spindle and at least once outwards from the circumferential direction of the spindle to prevent the device from getting stuck in uneven pipe systems.

An insert apparatus for protecting a curved inner surface within a passageway from abrasion during an abrasive machining operation is disclosed. In various embodiments, the insert apparatus includes a shield having a shell shaped to match a curved portion of the curved inner surface of the passageway and a shaft having a first end connected to the shell and a second end connected to a member configured to maintain the shaft within the passageway and the shell positioned against the curved inner surface during the abrasive machining operation.