Cutting – Tool or tool with support – Joint or connection
Reexamination Certificate
1999-11-01
2001-08-28
Bray, W. Donald (Department: 3725)
Cutting
Tool or tool with support
Joint or connection
C072S474000, C072S446000, C074S81300L, C083S050000, C083S552000, C083S571000, C400S134000, C408S035000
Reexamination Certificate
active
06279445
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to an alignment apparatus for a multi-tool of the type employed in punch presses.
BACKGROUND OF THE INVENTION
Punch presses commonly have an actuating ram, an upper platform which holds a punching tool, and a lower platform that supports a die in vertical alignment with the punching tool. Turret-type punch presses utilize a rotatable upper platform that has a series of tool mounting stations arranged around its periphery for receiving different punching or marking tools. Rotation of the platform brings a selected punch into position above a work station and beneath the ram. A lower platform is provided with a corresponding series of dies, and is rotatable with the upper platform to enable the proper die to be aligned with a selected punch.
Certain punch tools themselves can be “multi-tools.” That is, a punching tool, instead of containing only a single punch, may contain a magazine bearing a series of vertically movable punches in circumferentially spaced bores. The magazine itself can be rotated, as by a worm gear or the like, about a central vertical axis so as to place the correct punch above a work piece in a work station. Multi-tool mechanisms of this type are used, for example, for punching selected numbers or letters into a work piece, as well as for punching holes through the thickness of a work piece. A lower magazine containing a plurality of corresponding dies also may be provided so that as the magazine containing the punches is rotated about its axis, the lower magazine is rotated as well to bring the appropriate die into vertical alignment with the selected punch.
Carried above a multi-tool magazine is a multi-tool carrying a striker. As the multi-tool is struck downwardly by the ram of a punch press, the striker is forced downwardly into contact with a vertically aligned punch, causing that punch in turn to strike the work piece. The width of the striker at its bottom end is generally less than the distance between adjacent punches in the magazine, so that the striker cannot strike more than one punch at a time.
The multi-tool commonly is prevented by its contact with the punch press ram from rotating as the magazine is rotated about its axis to bring a selected tool into vertical alignment with the striker. In a typical procedure, the punch press ram descends into a rotationally locking engagement with the multi-tool, following which the magazine is rotated to bring a selected punch into alignment with the striker, and then the multi-tool is depressed further by the ram to cause the striker to engage the aligned punch in a punching operation.
The striker housing and tool ram have faces configured so that when they are brought together, the striker housing is rotationally locked to the punch press ram. The punch press ram, for example, may have a flat, generally rectangular shaped bottom surface that is received into a complementary slot or other configuration of the striker housing so that the striker housing is held rotationally stationary by the punch press ram.
A problem arises with certain punch presses in that the precise angular position of the punch press ram cannot be assured each time the striker housing is positioned over a tool ram. Rotational misalignment between the punch press ram and the striker housing may only be on the order of a few degrees, but may yet be sufficient to prevent the striker housing and the punch press ram from rotationally locking together. Rotational misalignment of the ram with the striker housing may prevent the punch press ram, as it descends into contact with the striker housing, from rotationally locking to the striker housing. The striker housing itself hence may undergo some rotation as the magazine is rotated, with the result that the striker is not aligned with the correct punching tool. The work piece accordingly may be ruined, and substantial damage may result to the striker housing.
It would be desirable to correct any misalignment of the striker housing and the punch press ram so as to enable them to rotationally lock together and prevent rotation of the striker housing as the tool magazine is rotated beneath it.
SUMMARY OF THE INVENTION
The present invention provides a self-aligning multi-tool for use in a punch press. The multi-tool includes a striker housing carrying a striker, and a magazine bearing a plurality of circumferentially spaced tools, the magazine being rotatable with respect to the striker housing so as to bring a desired tool into alignment with the striker to enable it to be struck by the striker.
The housing has a striking surface adapted to be engaged by the ram of a punch press and configured to rotationally lock to the ram when correctly rotationally aligned therewith to prevent the striker housing from rotating as the magazine is rotated. The housing includes at least one alignment pin having a tapered cam surface and positioned such that the punch press ram will contact and cam against the tapered cam surface of the pin as the ram approaches the striking surface if the striker housing and striking surface are rotationally misaligned, thus urging the striker housing to rotate into correct alignment with the ram to enable rotational locking therebetween.
In a preferred embodiment, a pair of alignment pins are received in recesses in the upper surface of the striker housing and are positioned to receive between them the ram to rotationally lock the ram to the housing. Springs are provided to urge the alignment pins upwardly, the recesses being configured to enable the pins to be substantially completely received in the recesses when the ram and striker housing are severely mis-aligned. The springs, which may be helical springs received in the recesses, are sufficiently stiff so that downward pressure of the ram against the camming surface of an alignment pin causes the striker housing to rotate, rather than to depress the pin into its recess, but preferably are sufficiently yielding as to enable a pin to be depressed within its recess if the housing is forcibly rotated by the magazine with respect to the ram to restrain damage to the ram or multi-tool.
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Rosene Ronald G.
Shuldes Glen M.
Timp Richard L.
Bray W. Donald
Fredrikson & Byron, P
Wilson Tool International Inc.
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