High strength fastener system
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.
1. A fastener system comprising:
a fastener having a head and a shank wherein the head is constructed having driver engageable surfaces and said driver engageable surfaces define multiple wings radially extending from a central core;
a driver having a bit end constructed with mating surfaces for engagement with the driver engageable surfaces of the recess in the fastener head and said mating surfaces define multiple projections radially extending from a central core matching the wings;
wherein each of said projections are constructed with a cross sectional shape comprising an installation surface, a tip portion and a removal surface that define the projection, and wherein each of the projections are connected by a transition surface extending between the installation and removal surfaces of adjacent projections and where the transition surface conforms to a circumference of the central core;
wherein the cross sectional shape comprises a projection having a width and a height and the ratio of the projection height to the projection width is equal to or less than 0.5; and
further wherein the driver engageable surfaces of the fastener head are constructed to receive the mating surfaces of the driver.
2. A fastener system according to claim 1 wherein the cross sectional shape comprises a central core having a first radius and a tip having a second radius and wherein the ratio of the first radius to the second radius is greater than 0.55.
3. A fastener system according to claim 2 wherein the ratio is greater than 0.65.
4. A fastener system according to claim 1 wherein the cross sectional shape comprises a central core having a first radius and a tip having a second radius and wherein the ratio of the first radius to the second radius is within the range of 0.65 to 0.70.
5. A fastener system according to claim 1 wherein the driver engageable surfaces are constructed in the shape of a spiral segment and said mating surfaces have a matching shape.
6. A fastener system, according to claim 1 wherein the projections are arranged in an hexalobular configuration.
7. A method of constructing a fastener system comprising:
forming a fastener having a head and a shank wherein the head is constructed having driver engageable surfaces and said driver engageable surfaces define multiple wings radially extending from a central core;
constructing a driver having a bit end having mating surfaces for engagement with the driver engageable surfaces of the fastener head and said mating surfaces define multiple projections radially extending from a central core matching the wings;
constructing each of said projections with a cross sectional shape comprising an installation surface, a tip portion and a removal surface that define the projection, and wherein each of the projections are connected by a transition surface extending between the installation and removal surfaces of adjacent projections and where the transition surface conforms to a circumference of the central core;
truncating each of the projections from the core outward and from the tip portion inward thereby forming each of the projections having a width and a height and the ratio of the projection height to the projection width is equal to or less than 0.5; and
forming the driver engageable surfaces of the fastener head to receive the mating surfaces of the driver.
8. The method according to claim 7 further comprising forming the central core having a first radius and the tip portion having a second radius and wherein the ratio of the first radius to the second radius is greater than 0.55.
9. The method according to claim 8 wherein the ratio is greater than 0.65.
10. The method according to claim 7 further comprising forming the central core having a first radius and the tip portion having a second radius and wherein the ratio of the first radius to the second radius is within the range of 0.65 to 0.70.
11. The method according to claim 7 wherein the driver engageable surfaces are constructed in the shape of a spiral segment and said mating surfaces have a matching shape.
12. The method according to claim 7 wherein the projections are arranged in an hexalobular configuration.
13. A fastener system comprising:
a fastener having a head and a shank wherein the head is constructed having driver engageable surfaces and said driver engageable surfaces define multiple wings radially extending from a central core;
a driver having a bit end constructed with mating surfaces for engagement with the driver engageable surfaces of the recess in the fastener head and said mating surfaces define multiple projections radially extending from a central core matching the wings;
wherein each of said projections are constructed with a cross sectional shape comprising an installation surface, a tip portion and a removal surface that define the projection, and wherein each of the projections are connected by a transition surface extending between the installation and removal surfaces of adjacent projections and where the transition surface conforms to a circumference of the central core;
wherein the driver engageable surfaces of the fastener head are constructed to receive the mating surfaces of the driver; and
further wherein the driver engageable surfaces are constructed in the shape of a spiral segment and said mating surfaces have a matching shape.
14. A method of constructing a fastener system comprising:
forming a fastener having a head and a shank wherein the head is constructed having driver engageable surfaces and said driver engageable surfaces define multiple wings radially extending from a central core;
constructing a driver having a bit end having mating surfaces for engagement with the driver engageable surfaces of the fastener head and said mating surfaces define multiple projections radially extending from a central core matching the wings;
constructing each of said projections with a cross sectional shape comprising an installation surface, a tip portion and a removal surface that define the projection, and wherein each of the projections are connected by a transition surface extending between the installation and removal surfaces of adjacent projections and where the transition surface conforms to a circumference of the central core;
forming the driver engageable surfaces of the fastener head to receive the mating surfaces of the driver; and
further wherein the driver engageable surfaces are constructed in the shape of a spiral segment and said mating surfaces have a matching shape.
15. A fastener system comprising:
a fastener having a head and a shank wherein the head is constructed having driver engageable surfaces and said driver engageable surfaces define multiple wings radially extending from a central core;
a driver having a bit end constructed with mating surfaces for engagement with the driver engageable surfaces of the recess in the fastener head and said mating surfaces define multiple projections radially extending from a central core matching the wings;
wherein each of said projections are constructed with a cross sectional shape comprising an installation surface, a tip portion and a removal surface that define the projection, and wherein each of the projections are connected by a transition surface extending between the installation and removal surfaces of adjacent projections and where the transition surface conforms to a concave circumference of the central core;
wherein the cross sectional shape comprises a central core having a first radius and a tip having a second radius and wherein the ratio of the first radius to the second radius is greater than 0.55; and
further wherein the driver engageable surfaces of the fastener head are constructed to receive the mating surfaces of the driver.
16. A method of constructing a fastener system comprising:
forming a fastener having a head and a shank wherein the head is constructed having driver engageable surfaces and said driver engageable surfaces define multiple wings radially extending from a central core;
constructing a driver having a bit end having mating surfaces for engagement with the driver engageable surfaces of the fastener head and said mating surfaces define multiple projections radially extending from a central core matching the wings;
constructing each of said projections with a cross sectional shape comprising an installation surface, a tip portion and a removal surface that define the projection, and wherein each of the projections are connected by a transition surface extending between the installation and removal surfaces of adjacent projections and where the transition surface conforms to a concave circumference of the central core;
forming the central core having a first radius and the tip portion having a second radius and wherein the ratio of the first radius to the second radius is greater than 0.55; and
forming the driver engageable surfaces of the fastener head to receive the mating surfaces of the driver.