Draw punch having relieved helical working faces
Patent 5727436 Issued on March 17, 1998. Estimated Expiration Date: 
March 27, 2015. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
March 27, 2015. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 1721007 1817223 2221904 2237069 3228268 3683499 Draw punch Slug-splitting punch Punch Punch gun InventorsAssigneeApplicationNo. 411414 filed on 03/27/1995US Classes:83/686, Shear-type male tool30/360, With portion positioned in work aperture30/361, Work-mounted83/689Progressive cuttingExaminersPrimary: Dexter, Clark F.Attorney, Agent or FirmForeign Patent References
International ClassB26F 001/14AbstractA draw punch of the type used for cutting holes in various materials such as sheet metal has a cylindrical body with a central bore through it and a cutting edge at the outside diameter of the body. A working face is defined at one end of the body between the cutting edge and the bore. The working face includes two diametral axial faces which extend from a root to a peak. The working face further includes two valleys located between the peak of one axial face and the root of the other axial face. Primary helical surfaces extend from a peak to a valley while secondary helical surfaces extend from the valley to the root. The helical surfaces are everywhere relieved in a radial direction from a plane normal to the axis of the body and intersecting any point on the cutting edge.Field of SearchShear-type male toolMultiple punchings Plural spaced successively operative shearing portions Progressive cutting To punch and cut punched article Punching tool Tool pair With portion positioned in work aperture Work-mounted Pointed With impact drive Including punch Plural-spaced cutting edges Having axial, core-receiving central portion Having inversely angled cutting edge | |
