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US 4,784,549 AGranted
Torque-limited collar
OwnerGeorge S. Winginventor
Life of this patent
Estimating the term…
Abstract
Axially-extending troughs in a bark of an internally-threaded collar receive setting balls of a driver that apply a torque to the collar through the balls bearing on the walls of the troughs. At a predetermined pre-load, the balls fail the bark and plow through it to develop circumferential furrows, and the torque application on the collar ends. A second torquing with balls at a different axial position fails the bark again at the same pre-load to compensate for any relaxation after the first torque application.
Claims15
An improvement in an internally threaded collar comprising:
- (a) external constant radius, axially-extending, annular bark means of the collar;
- (b) at least one axially-extending trough in the bark means for accepting a setting element of a driver;
- and
- (c) a portion of the bark means failing substantially completely in circumferential compression in response to circumferential bearing by the setting element to develop a circumferentially-extending furrow in the bark, the bark means being such that the failure occurs at a predetermined pre-load and the failed bark material remains integral with the balance of the bark means.
1 more element
An improved female fastener comprising:
- (a) a base having an annular sheet bearing end;
- (b) constant radius bark means axially adjacent the base;
- (c) an axial bore through the fastener;
- (d) an internal thread in the axial bore;
- (e) a plurality of regularly-spaced and axially-extending troughs in the bark adapted to receive setting elements of a driver;
- and
- (f) a portion of the bark means failing substantially completely in circumferential compression by bearing of the setting elements on the bark upon a predetermined pre-load applied by the fastener to a sheet during the fabrication of a joint to develop a circumferentially-extending furrow in the bark means for each of the setting elements, the failed bark material remaining integral with the balance of the bark means.
4 more elements
Dependencies are inferred from the claim text.