Patent ID: 8690504

Claim:
A removable torque-limited fastener configured to turn about an axis in a fastening direction for fastening and turned about the axis in an opposite loosening direction for loosening, the fastener comprising: a fastening head and a fastening body integral with the fastening head, the fastening head configured to be turned in a fastening direction about an axis of rotation and turned in an opposite loosening direction about the axis; the fastening head comprising a base, a set of lugs, a set of first recesses, and a set of ramps, the set of lugs comprising one or more lugs and the set of ramps comprising one or more ramps; if the set of lugs comprises more than one lug, the lugs are circumferentially spaced apart from one another about the axis, if the set of ramps comprises more than one ramp, the ramps are circumferentially spaced apart from one another about the axis; each lug comprising a fastening abutment surface extending axially away from the base and facing the loosening direction; each first recess formed in the base and associated with a respective lug of the set of lugs, each first recess extending away from the lug associated with said first recess; each ramp comprising a loosening abutment surface extending axially away from the base, the loosening abutment surface facing the fastening direction, and an inclined cam surface extending in the loosening direction away from the loosening abutment surface, the cam surface inclined axially towards the base in the loosening direction; the set of loosening abutment surfaces facing a second recess at least partially defined by the set of ramps, the second recess to receive a loosening tool that has a set of drive surfaces that bear against the set of loosening abutment surfaces when the loosening tool is inserted into the second recess and applying torque urging the fastener to turn in the loosening direction; the set of fastening abutment surfaces facing a third recess at least partially defined by the set of lugs, the third recess to receive a fastening tool that has a set of drive surfaces that bear against the set of fastening abutment surfaces when the fastening tool is inserted into the third recess and applying torque urging the fastener to turn in the fastening direction; and the set of lugs configured to plastically deform into the set of first recesses upon the limiting torque being applied by the fastening tool so that the fastening abutment surfaces of the lugs no longer engage the drive surfaces of the fastening tool upon a limiting torque being applied to the fastener head by the fastening tool so that the torque transferred from the fastening tool to the fastener head is limited to the limiting torque.