.~> Embodying three or more tools (e.g., tube expander)
DEFINITION
Classification: 72/392
BY RELATIVELY RECEDING WORK-ENGAGING TOOL FACES (E.G., FORSTRETCHING):
(under the class definition) Device comprising a plurality of distinct tools each having at least one tool-face* and means to move or to guide the motion of one of said tools relative to another tool along a predetermined path in such direction that the distance between the tool-faces generally increases from an initial minimum spacing throughout an operation of the class type.
(1) Note. The tools may be pegs or lugs which engage in apertures in the work or in the interior of ring-shaped or U-shaped work, and which move apart to stretch the work, either locally or as a whole, usually involving a major
change of shape of a specific workpiece.
(2) Note. For tools which move generally toward and past each other without tool-face conflict, while deforming work, see subclasses 380+, above.
(3) Note. For devices having concentric receding tool faces which stretch work (such as the mandrel of a "Huck" rivet), see subclasses 391.2+; these tool faces are radially offset, rather than directly opposed in the direction of tool motion. The distinction is illustrated in Figures A and B of the diagram accompanying subclasses 391.2+.
(4) Note. This subclass includes disclosures of devices, such as a tire-stretcher, which comprise a split ring and means to expand it; the effect is substantially that of distinct receding tool-faces.
