Using phase change expansion of a substance to perform work on a workpiece

Abstract

Apparatus and method for working of a workpiece use the expansion of water in a container during the freezing process to drive a piston against a workpiece that is positioned to at least partially overlie a cross-sectional area of a hollow interior of the container. Use of a piston with a tapered working end focuses the resulting force against a small area of the workpiece in order to produce a bend in the workpiece at the point of application. In environments where conventional bending tools are not available, the apparatus can be used to perform bending or other operations on workpieces of varying materials.

1 . Apparatus for working of a workpiece, the apparatus comprising:
 a container comprising a hollow interior space for receipt of a substance known to expand when transitioning from one phase to another;   a closure member for closing off a respective end of the hollow interior space of the container in a fluid-tight manner containing the substance within the hollow cylindrical interior space at said respective end;   a piston slidable within a cylindrical portion of the hollow interior space of the container along an axis of said hollow interior space;   a fluid-tight seal between the piston and a boundary wall closing around the axis of the hollow space for containing the substance within the hollow interior space between the piston and the closure member; and   a workpiece support feature arranged to support the workpiece in a position placing at least part of the workpiece over a cross-sectional area of the hollow interior space of the container.   
     
     
         2 . Apparatus for working of a workpiece, the apparatus comprising:
 a container comprising a hollow interior space containing a substance known to expand when transitioning from one phase to another;   a closure member closing off a respective end of the hollow interior space of the container in a fluid-tight manner;   a piston slidably disposed within a cylindrical portion of the hollow interior space of the container;   a fluid-tight seal between the piston and a boundary wall closing around the axis of the hollow space to contain the substance within the hollow interior space between the fluid-tight seal and the closure member; and   a workpiece support feature arranged to support the workpiece in a position placing at least part of the workpiece over a cross-sectional area of the hollow interior space of the container.   
     
     
         3 . The apparatus of  claim 1  wherein the workpiece support feature comprises a workpiece passage extending into said container and passing through the hollow interior space thereof at a distance from the closure member for receipt of the workpiece in the passage in a position placing a part of the workpiece within the hollow interior of the container. 
     
     
         4 . The apparatus of  claim 2  wherein the workpiece support feature comprises a workpiece passage extending into said container and passing through the hollow interior space on a side of the piston opposite the closure member for receipt of the workpiece in the passage in a position placing part of the workpiece within the hollow interior of the container. 
     
     
         5 . The apparatus of  claim 3  wherein the workpiece passage comprises a cylindrical bore. 
     
     
         6 . The apparatus of  claim 1  wherein the closure member is removably engagable to the container for selective opening and closing of the respective end of the hollow interior space. 
     
     
         7 . The apparatus of  claim 6  wherein the closure member and the container are matingly threaded. 
     
     
         8 . The apparatus of  claim 1  wherein a working end of the piston comprises a non-planar surface for working the workpiece. 
     
     
         9 . The apparatus of  claim 8  wherein the working end of the piston is at least partially conical. 
     
     
         10 . The apparatus of  claim 8  wherein the working end of the piston is wedge-shaped. 
     
     
         11 . The apparatus of  claim 1  further comprising a cover for closing off a second end of the hollow interior space. 
     
     
         12 . The apparatus of  claim 11  wherein the cover is selectively engagable to and removable from the container. 
     
     
         13 . The apparatus of  claim 1  wherein the piston is one of a plurality of differently shaped pistons selectable for use within the hollow interior. 
     
     
         14 . The apparatus of  claim 13  wherein each piston comprises a peaked end tapering at a respectively different angle. 
     
     
         15 . The apparatus of  claim 2  wherein the substance is one that expands as it transitions into a solid state. 
     
     
         16 . The apparatus of  claim 15  wherein the substance is water. 
     
     
         17 . A method of working a workpiece, the method comprising:
 (a) providing a container comprising a hollow interior space that has at least one closed end and contains a substance known to expand when transitioning from one phase to another;   (b) positioning the workpiece in a manner holding at least part of the workpiece over a cross-sectional area of the hollow interior space of the container; and   (c) with the substance contained between the closed end of the hollow interior space and a piston slidably disposed within a cylindrical portion of the hollow interior space, causing the substance to transition from the one phase to the other to force the piston against the workpiece to perform a working operation thereon.   
     
     
         18 . The method of  claim 17  wherein step (b) comprises inserting the workpiece into a workpiece passage that extends into the container and passes through the hollow interior space thereof on a side of the piston opposite the closure member. 
     
     
         19 . The method of  claim 17  wherein step (c) comprises causing the substance to solidify. 
     
     
         20 . The method of  claim 17  wherein step (c) comprises cooling the substance.