Metal deforming – By use of tool acting during relative rotation between tool... – Tool orbiting or rotating about an axis
Reexamination Certificate
2000-02-11
2001-04-17
Tolan, Ed (Department: 3725)
Metal deforming
By use of tool acting during relative rotation between tool...
Tool orbiting or rotating about an axis
C072S082000, C072S094000, C072S120000
Reexamination Certificate
active
06216512
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of Invention
The invention relates to a method for forming a portion of a workpiece, such as a cylinder or shell, and an apparatus therefor, especially the method and apparatus for forming the portion of the workpiece by spinning to form a changed diameter portion having a central axis that is at least one of offset from and oblique to a central axis of an unprocessed portion of the workpiece.
2. Description of Related Art
In Japanese Patent Laid-open Publication No. 3-226327, disclosed is a method for forming an end portion of a cylindrical member (hereinafter, simply referred to as a cylinder) made of metal to form a reduced diameter portion on the end portion. According to the Publication, a spinning process is performed by supporting the cylinder with a chuck and rotating it about its axis, and moving a roller for forming toward the axis to reduce the diameter of the cylinder, thereby to form the reduced diameter portion having a neck portion and a tapered portion. In general, the spinning process is employed to form a plate into a shell. Likewise, a flange and neck portion can be formed by spin flow forming into a cylindrical can body, as disclosed in U.S. Pat. No. 4,563,887. Furthermore, a computerized spinning machine has been proposed in Japanese Patent No. 2,534,530.
Recently, it has been requested to form a reduced diameter end portion having an oblique axis inclined against the central axis of the metal cylinder. When the metal cylinder is used for an outer shell of a muffler of an automotive vehicle, for example, the cylinder will be easily mounted in a vehicle. Also, when the metal cylinder is used for a housing of a catalytic converter, it will be easily located near an engine, to reduce the time of increasing the temperature of the catalyst. Furthermore, dual converters may be easily assembled, with their neck portions positioned close to each other.
According to the prior methods for forming the cylinder or shell by the spinning process, the reduced diameter portion was formed to be coaxial with the main body of the cylinder, but the reduced diameter end portion having the oblique axis could not be formed. In order to produce the cylinder like the shell or housing as described above, therefore, the portions corresponding to the main body and the reduced diameter portion were formed by press working, and then these components were connected together by welding or the like. According to these methods, however, the produced cylinder can not be expected to be so strong, comparing with that of the integral construction. Furthermore, they need the connecting process, different from the forming process, so that it is difficult to produce the cylinder by those methods, and it is almost impossible to produce the cylinder by the computerized forming process as described in the prior publication. As a result, the manufacturing cost of the cylinder shall be increased, comparing with the cylinder of the coaxial type formed by the spinning process.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the invention to provide a method for forming a changed diameter portion of a workpiece having a central axis that is at least one of offset from and oblique to a central axis of an unprocessed portion of the workpiece, easily and properly by a spinning process.
It is another object of the invention to provide an apparatus for forming a changed diameter portion having a central axis at least one of offset from and oblique to a central axis of an unprocessed portion of the workpiece, easily and properly by a spinning process.
In accomplishing the above and other objects, the method for forming the changed diameter portion of the workpiece by spinning may comprise supporting the workpiece so that a central axis of the portion to be processed is at least one of offset from and oblique to a forming target axis and molding the portion to be processed by a spinning process so that the central axis of the portion to be processed is matched to the forming target axis and simultaneously changing the diameter of the portion to be processed.
The apparatus for forming the changed diameter portion of the workpiece by spinning may comprise devices for performing the steps as described above. For example, the apparatus may include at least one roller operatively mounted on a rotatable member rotatable about a main axis to be radially movable to and from the main axis, and in contact with a surface of the portion to be processed. In the apparatus, a first driving device may be provided for moving at least one of the workpiece and the at least one roller relative to each other so that a central axis of the portion to be processed is at least one of offset from and oblique to a forming target axis that at least partially overlaps the main axis. A second driving device may be provided for moving the at least one roller radially toward the forming target axis, with the at least one roller being in substantial contact with a surface of the portion to be processed, and rotating the at least one roller about the main main axis relative to the workpiece. A controller controls the first and second driving devices to form the portion to be processed into a changed diameter portion having the forming target axis.
According to the method and apparatus as described above, the changed diameter portion may be formed to provide a tapered portion, with the diameter of the workpiece gradually changed from an unprocessed portion toward an end of the changed diameter portion. The changed diameter portion may be formed to provide the tapered portion and a neck portion of a tubular configuration extending from the tapered portion.
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Oliff & Berridg,e PLC
Sango Co. Ltd.
Tolan Ed
LandOfFree
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