Interference surfaces are constructed on inner transition surfaces between wings of a fastener having a spiral recess. A portion of the transition surface is tapered to provide the interference. A standard driver for a spiral recess will engage the interference surface to create a “stick fit” engagement. The punch is formed using a wire EDM operation to construct tapered surfaces within the die cavity of a hob. The hob is machined down to obtain the desired depth, which is measured up from a gage spot indicative of the sticking point.
The fastener of this application is designed to facilitate the insertion of rotating power driven tools into the fastener recess. The recess of this fastener generally uses spirally configured driving surfaces and is formed in a counterbore in the upper surface of the fastener. The driving lobes have upper surfaces that are depressed a distance into the counterbore. A ramp surface is formed on each of the upper surfaces that causes a spinning bit to fall into the recess in an engaged manner. The ramp surfaces are constructed with both removal and installation ramp portions.
Spiral Drive Fastener With Friction Engageable Surface
Interference surfaces are constructed on inner transition surfaces between wings of a fastener having a spiral recess. A portion of the transition surface is tapered to provide the interference. A standard driver for a spiral recess will engage the interference surface to create a “stick fit” engagement. The punch is formed using a wire EDM operation to construct tapered surfaces within the die cavity of a hob. The hob is machined down to obtain the desired depth, which is measured up from a gage spot indicative of the sticking point.
Interference surfaces are constructed on inner transition surfaces between wings of a fastener having a spiral recess. A portion of the transition surface is tapered to provide the interference. A standard driver for a spiral recess will engage the interference surface to create a “stick fit” engagement. The punch is formed using a wire EDM operation to construct tapered surfaces within the die cavity of a hob. The hob is machined down to obtain the desired depth, which is measured up from a gage spot indicative of the sticking point.
Fastener System With Stable Engagement And Stick Fit
Barry J. Hughes - Arden, GB Gary Dilling - Gardner MA, US
Assignee:
Phillips Screw Company - Burlington MA
International Classification:
B25B 23/00 F16B 23/00
US Classification:
81460, 411404, 411409, 411410
Abstract:
Various embodiments described herein provide a fastener system having straight walled driving surfaces that provides a reliable stick fit feature, while also improving stability of engagement between the system components. A feature of the new system is to allow engagement of existing standard straight walled drivers in the new system.
Fastener Systems And Methods Of Forming Fastener Systems With Stable Engagement And Stick Fit
Barry J. Hughes - Arden, GB Gary Dilling - Gardner MA, US
Assignee:
Phillips Screw Company - Burlington MA
International Classification:
B25B 23/00 F16B 23/00
US Classification:
81460, 411404, 411409
Abstract:
Various embodiments described herein provide a fastener system having straight walled driving surfaces that provides a reliable stick fit feature, while also improving stability of engagement between the system components. A feature of the new system is to allow engagement of existing standard straight walled drivers in the new system.
The fastener of this application is designed to facilitate the insertion of rotating power driven tools into the fastener recess. The recess of this fastener generally uses spirally configured driving surfaces and is formed in a counterbore in the upper surface of the fastener. The driving lobes have upper surfaces that are depressed a distance into the counterbore. A ramp surface is formed on each of the upper surfaces that causes a spinning bit to fall into the recess in an engaged manner. The ramp surfaces are constructed with both removal and installation ramp portions.
A fastener system is constructed wherein the installation and removal drive surfaces intersect an enlarged core diameter in a transitional surface that extends between the installation and removal surfaces of adjacent wings. The transitional surface has a concave form that conforms to the core diameter. The projections of the driver in the system are formed in a blunt shape.