Metal deforming – By three or more coacting relatively movable tools – Concurrently actuated tools
Reexamination Certificate
2002-04-05
2004-04-13
Crane, Daniel C. (Department: 3725)
Metal deforming
By three or more coacting relatively movable tools
Concurrently actuated tools
C072S416000, C072S466800
Reexamination Certificate
active
06718814
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to the field of machine tools, and more particularly, to the field of tools that operate to reduce the size or diameter of a work piece, or swaging tools.
BACKGROUND OF THE INVENTION
Swaging is a method that is employed to reduce the diameter or thickness of a rod-like or tube-like structure. Swaging may be carried out by forging, squeezing or hammering the work piece. In one type of swaging tool, the work piece is fed into an opening formed by a plurality of die segments arranged generally in a circle. The die segments are forced radially inward to a predetermined point. As the die segments travel radially inward, they converge on the work piece and strike the outer diameter of the work piece, thereby tending to reduce the diameter of the work piece. To force the die segments inward, a moveable tool assembly often engages the outside of the die segments to push them radially inward.
After the swaging operation, the die segments are in a compressed state, substantially surrounding the work piece. To remove the work piece, the die segments must be moved radially backward to an non-compressed or expanded state. Once the die segments are in their normal expanded state, the work piece may be removed and another work piece may be inserted. The process may then be repeated.
In some cases, the swaging mechanism is used on portions of a continuous work piece such as a long continuous tube or pipe. In such cases, the swaging mechanism may operate in a substantially similar manner as described above, except that when the swaging die segments move to the expanded state after swaging one portion of the continuous work piece, the work piece is simply advanced to place an adjacent portion of the work piece in position to be swaged.
In any event, an important part of the swaging operation is the decompression or expansion of the swaging die segments after the swaging step to allow replacement or advancement of the work piece. If the die segments are secured to the moveable tool, then the movement of the moveable tool in the reverse direction would also cause the expansion of the dies segments after completion of the swaging operation. However, it is typically easier to build swaging tools where the moveable tool is not secured to the die segments, but merely engages and pushes the die segments into the compressed state. In such devices, reverse movement of the moveable tool does not move the die segments.
Accordingly, it is desirable to design swaging die segments that are capable of self-separation once the compression force is removed. To this end, the prior art swaging die segments sometimes included springs disposed between adjacent die segments. In particular, when the swaging force is removed from the die segments, the springs tended to push the adjacent die segments apart. As the die segments separated, they moved radially backward away from the work piece.
While the use of springs that are placed between adjacent die segments assists in moving die segments away from the work piece, the springs can be difficult to handle. For example, when the die segments are placed within the swager, each die segment must be individually placed and a spring lodged between the die segment and its adjacent die segment. Thus, replacement of die segments can be difficult.
What is needed, therefore, is a die segment assembly that is both self-separating but does lacks the handling difficulties associated with the use of springs that are trapped between adjacent dies.
SUMMARY OF THE INVENTION
The present invention addresses the above needs, as well as others, by providing a tool die assembly that incorporates a compressible spacing element that may be coupled to at least one of two adjacent die segments. When the compressible spacing element is positively coupled to one or both die segments, handling of the assembly is much easier. Moreover, use of a compressible spacing element that is made of polymer, and/or that has a non-helical, more axially continuous construction, provides compressibility without the inconvenience of springs, and may be more readily coupled to the die segments.
A first embodiment of the present invention is a swaging die assembly that includes a plurality of die segments and a plurality of compressible spacing elements. Each die segment has a work surface for contacting a workpiece and is movable in a first direction. Each compressible spacing element is interposed between an adjacent pair of compressible spacing elements. Each compressible spacing element is configured to exert a separation force between the adjacent pair of compressible spacing elements. At least one of the compressible spacing elements constructed of polymeric material.
A second embodiment of the present invention is also a swaging die assembly that includes a plurality of die segments and a plurality of compressible spacing elements. Again, each die segment has a work surface for contacting a workpiece and is movable in a first direction. Each compressible spacing element is interposed between an adjacent pair of compressible spacing elements and is configured to exert a separation force between the adjacent pair of compressible spacing elements. In the second embodiment, at one least compressible spacing element has an axial dimension extending between the adjacent pair of compressible spacing elements, the at least one compressible spacing element having a continuous axial structure (i.e. non-helical) in an uncompressed state.
A third embodiment of the present invention is similarly a swaging die assembly that includes a plurality of die segments and a plurality of compressible spacing elements. Again, each die segment has a work surface for contacting a workpiece and is movable in a first direction. Each compressible spacing element is interposed between an adjacent pair of compressible spacing elements and is configured to exert a separation force between the adjacent pair of compressible spacing elements. In accordance with a third embodiment, at least one compressible spacing element secured to each of the adjacent pair of die segments, preferably using a coupling member.
The above-described features and advantages, as well as others, will become more readily apparent to those of ordinary skill in the art by reference to the following detailed description and the accompanying drawings.
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Bartrom Michael A.
Waters Carl D.
Computer Age Engineering
Crane Daniel C.
Maginot Moore & Beck
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