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Patent Searching and Data


Title:
MACHINING METHOD FOR BURRED FLAT HOLES IN METAL PLATES
Document Type and Number:
WIPO Patent Application WO/2018/124255
Kind Code:
A1
Abstract:
Provided is a machining method for burred flat holes that, regardless of the size of flat holes or the burring height around the edges of same, is highly flexible, widely applicable, and simple. This method has: a first step in which an overhang punch, having a flat cross-section orthogonal to the pressing direction, is pressed on to the surface of a metal plate and to form a flat overhang section having a flat cross-section; a second step in which a perforating punch having a flat cross-section orthogonal to the pressing direction is pressed on to the bottom surface of the formed overhang section and a hole having a flat plane is formed in said section; and a third step in which a burring punch is pressed on to the peripheral edge of the formed hole and burring is formed by pulling up said section. The overhang punch and the perforating punch each have: a pair of side surfaces 2a, 4a parallel to the pressing direction and positioned at both ends in the longitudinal direction of the cross-section ("major axis direction"); and a pair of side surfaces 2b, 4b positioned at both ends in the width direction of the cross-section ("minor axis direction"). The difference 7n – 2n between a side surface gap 7n at both ends in the major axis direction of the cross-section of the burring punch 7 and the side surface gap 2n at both ends in the major axis direction of the cross-section of the overhang punch 2 is set smaller, as 7n – 2n < 7m – 2m, than the difference 7m – 2m between the side surface gap 7m at both ends in the minor axis direction of the cross-section of the burring punch 7 and the side surface gap 2m in the minor axis direction of the cross-section of the overhang punch 2.

Inventors:
TAKASE MASAAKI (JP)
Application Number:
PCT/JP2017/047147
Publication Date:
July 05, 2018
Filing Date:
December 20, 2017
Export Citation:
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Assignee:
T RAD CO LTD (JP)
International Classes:
B21D19/08; F28F9/04
Foreign References:
JPH08267147A1996-10-15
US20140158333A12014-06-12
JP2004202549A2004-07-22
Attorney, Agent or Firm:
KUBOTA Takubi (JP)
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