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US 2001/0026737 A1Published application
Bit for removing damaged screws
AssigneeAlden Corporation
InventorPeter J. Bergamo
Life of this patent
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AssigneeAlden Corporation
InventorPeter J. Bergamo
Estimating the term…
This bit has an axis and a tip end with an obtuse angle. There are multiple scraping surfaces, each facing counter-clockwise into a longitudinal recess in the tip end. Each scraping surface has a scraping edge at an angle of about 55° to 70° to the axis. Behind each scraping surface the outer surface of the tip end curves down to a rearward edge adjacent another of the longitudinal recesses, the rearward edges each being disposed at a sharper angle to the axis than the scraping edge so that there is some relief, allowing the scraping edge to be more pronounced and enhance its ability to dig into the metal of a deformed screw at points removed from the axis to get a good purchase on the screw.
For removing damaged screws, a bit having an axis and a tip end formed with a point, the tip end having a plurality of longitudinal recesses uniformly disposed about the tip end, each bordered by a longitudinal surface facing in a counter-clockwise direction and being in a plane including the axis, and formed with a straight scraping edge, the scraping edges of the recesses each being at an angle in the range of 55° 70° to the axis and a support portion behind each scraping edge, the support portions each defined by a relief surface curving away from the scraping edge down to a rearward edge bordering one of the longitudinal recesses, each rearward edge also lying in a plane including the axis and being disposed at more acute angle to the axis than the scraping edge angle.
A method for unscrewing threaded fasteners installed in an object and having a head with a deformed end surface, the method comprising the steps of:
Dependencies are inferred from the claim text.