Cutting – Tool engages work during dwell of intermittent workfeed – Means to change tool position – or length or datum position...
Reexamination Certificate
1999-10-22
2001-05-08
Bray, W. Donald (Department: 3725)
Cutting
Tool engages work during dwell of intermittent workfeed
Means to change tool position, or length or datum position...
C083S215000, C083S236000, C083S251000, C083S263000, C083S315000, C083S559000
Reexamination Certificate
active
06227090
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to an oscillating assembly for pivoting a blanking die.
BACKGROUND OF THE INVENTION
It has been known to pivot a blanking die in an oscillatory manner between angularly displaced cutting positions wherein the die cuts through sheet material, such as steel, in order to form trapezoidal blanks. Trapezoidal blanks are particularly desirable when forming components having a tapered configuration, such as an automobile hood, because they reduce the amount of material which must be trimmed off and discarded as scrap, thereby realizing a savings in material and manufacturing costs. Some known assemblies have utilized air cylinders to drive the blanking die about its pivot axis. However, utilizing air cylinders is relatively slow and it is difficult to control the angular displacement of the blanking die with a desirable degree of precision.
Other types of assemblies utilize a servomotor and gear the servomotor to a vertically extending turnable shaft which is coextensive with the pivot axis of the die. An example of such an assembly is disclosed in U.S. Pat. No. 4,942,797 to Nakamura. In the assembly of the '797 patent, a series of intermeshed gears are used to translate the rotation of the servomotor into turning of the turnable shaft and pivotal movement of the die. Over time, the teeth on these gears may wear down. Furthermore, utilization of a plurality of intermeshed gears increases the complexity and cost of the assembly and its maintenance.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide an oscillating assembly for pivoting a blanking die which is simpler in construction and affords a relatively high degree of precision in controlling the pivotal movement of the die mounted thereon. It is also an object of the present invention to provide an oscillating assembly which is able to rapidly oscillate between angularly displaced cutting positions so as to increase manufacturing efficiency.
To achieve these objects, the present invention provides an oscillating assembly for pivoting a blanking die that is constructed and arranged to cut blanks from sheet material. The oscillating assembly comprises a die supporting structure that pivots about a pivot axis. The die supporting structure receives and supports the die such that the sheet material can be fed into the die in a feeding direction and such that the pivoting of the die supporting structure pivots the die relative to the sheet material. A reversible rotary driving assembly rotates a rotatable output shaft in opposing first and second rotational directions. A linearly movable die driver is operatively connected to the output shaft such that (a) rotating the shaft in the first rotational direction thereof moves the die driver generally linearly in a first die driving direction and (b) rotating the shaft in the second rotational direction thereof moves the die driver generally linearly in a second die driving direction opposite the first die driving direction. The die driver is operatively connected to the die supporting structure such that (a) moving the die driver in the first die driving direction thereof as aforesaid pivots the die supporting structure to a first cutting position wherein the blanking die can cut a first blank from the sheet material fed therein and (b) after cutting the first blank and advancing the sheet material relative to the die in the feeding direction, moving the die driver in the second die driving direction thereof as aforesaid pivots the die supporting structure to a second cutting position wherein the blanking die can cut a second blank from the sheet material.
Other objects, features, and advantages of present invention will become apparent from the following detailed description and the accompanying drawings.
REFERENCES:
patent: 2269714 (1942-01-01), Fenton
patent: 3440910 (1969-04-01), Scribner
patent: 3455197 (1969-07-01), Richardson
patent: 4077287 (1978-03-01), Makeev et al.
patent: 4606250 (1986-08-01), Krosbacher et al.
patent: 4739683 (1988-04-01), Ogawa
patent: 4869141 (1989-09-01), Klingel
patent: 4942797 (1990-07-01), Nakamura
patent: 5113733 (1992-05-01), Peterson et al.
Bray W. Donald
Cosma International Inc.
Pillsbury & Winthrop LLP
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