A thermally stabilized fastener system and method is disclosed. The disclosed system/method integrates a fastener (FAS) incorporating a faster retention head (FRH), fastener retention body (FRB), and fastener retention tip (FRT) to couple a mechanical member stack (MMS) in a thermally stabilized fashion using a fastener retention receiver (FRR). The MMS includes a temperature compensating member (TCM), a first retention member (FRM), and an optional second retention member (SRM). The TCM is constructed using a tailored thermal expansion coefficient (TTC) that permits the TCM to compensate for the thermal expansion characteristics of the FAS, FRM, and SRM such that the force applied by the FRH and FRR portions of the FAS to the MMS is tailored to a specific temperature force profile (TFP) over changes in MMS/FAS temperature. The TCM may be selected with a TTC to achieve a uniform TFP over changes in MMS/FAS temperature.

A blow-by gas treatment device for an internal combustion engine includes: a positive crankcase ventilation (PCV) separator configured to be fastened to the internal combustion engine with a plurality of bolts; and one of a single sealant or a plurality of sealants configured to seal gas leakage of blow-by gas from a gap between the internal combustion engine and the PCV separator; wherein the plurality of bolts includes at least one break head bolt and three or more unbreakable head bolts, the unbreakable head bolt being a bolt in which a bolt head is not separated even when a fastening torque corresponding to a tightening torque applied to the break head bolt is applied to the bolt head.

A blow-by gas treatment device for an internal combustion engine includes: a positive crankcase ventilation (PCV) separator configured to be fastened to the internal combustion engine with a plurality of bolts; and one of a single sealant or a plurality of sealants configured to seal gas leakage of blow-by gas from a gap between the internal combustion engine and the PCV separator; wherein the plurality of bolts includes at least one break head bolt and three or more unbreakable head bolts, the unbreakable head bolt being a bolt in which a bolt head is not separated even when a fastening torque corresponding to a tightening torque applied to the break head bolt is applied to the bolt head.

An explosive bolt is provided for securing a brace in tension. The bolt includes a bar, a pair of explosives, a pair of detonators and a pair of anchors. The bar has opposing longitudinal ends and an outer thickness. Opposing bores extend inwardly from the longitudinal ends to corresponding depth ends. First and second notches reduce the thickness proximate to the corresponding depth ends. A center rod separates the notches from each other. Each explosive correspondingly inserts into a corresponding bore to a corresponding depth end. Each detonator correspondingly inserts into the corresponding bore. Each anchor secures the bar to the brace. In further embodiments, the longitudinal ends include helical male threads, and the anchors are nuts having helical female threads.

An explosive bolt is provided for securing a brace in tension. The bolt includes a bar, a pair of explosives, a pair of detonators and a pair of anchors. The bar has opposing longitudinal ends and an outer thickness. Opposing bores extend inwardly from the longitudinal ends to corresponding depth ends. First and second notches reduce the thickness proximate to the corresponding depth ends. A center rod separates the notches from each other. Each explosive correspondingly inserts into a corresponding bore to a corresponding depth end. Each detonator correspondingly inserts into the corresponding bore. Each anchor secures the bar to the brace. In further embodiments, the longitudinal ends include helical male threads, and the anchors are nuts having helical female threads.

Disclosed is a fastener assembly comprising: a bolt member, comprising a bolt head and a shank, at least a part of which is screw threaded; a nut member for threaded engagement with the shank; a first drive element allocated to the bolt member and a second drive element allocated to the nut member, each drive element comprising a body and adapted for engagement by a corresponding tool. The body of the first drive element is joined to the bolt member by a first interposed interlayer structure. The body of the second drive element is joined to the nut member by a second interposed interlayer structure. The first interlayer structure is adapted to fracture in response to relative rotational and/or tensile force applied to the first drive element. The second interlayer structure is adapted to fracture in response to relative rotational and/or tensile force applied to the second drive element.

A tie-rod assembly includes a tube member having a first set of threads at a first end of the tube member and a second set of threads at a second end of the tube member. The tie-rod assembly includes a first clevis coupling assembly having a first width dimension and a third set of threads compatible with first set of threads and first clevis coupling assembly has a second width dimension which includes a portion of the third set of threads with the second width dimension greater than the first width dimension. Further included is second clevis coupling assembly having a third width dimension and a fourth set of threads compatible with second set of threads and the second clevis coupling assembly has a fourth width dimension which includes a portion of the fourth set of threads with the fourth width dimension greater than the third width dimension.

A tie-rod assembly includes a tube member having a first set of threads at a first end of the tube member and a second set of threads at a second end of the tube member. The tie-rod assembly includes a first clevis coupling assembly having a first width dimension and a third set of threads compatible with first set of threads and first clevis coupling assembly has a second width dimension which includes a portion of the third set of threads with the second width dimension greater than the first width dimension. Further included is second clevis coupling assembly having a third width dimension and a fourth set of threads compatible with second set of threads and the second clevis coupling assembly has a fourth width dimension which includes a portion of the fourth set of threads with the fourth width dimension greater than the third width dimension.

An axially separable fastener for securing a structure is provided to detach upon command of an electric signal. The fastener includes a metal bolt, an external nut, a frangible ampoule containing a liquid metal eutectic and an internal plug. The bolt has a metal shank with proximal and distal ends. The shank includes a first head at the proximal end, and a first helical external thread and an axial bore with a first helical internal thread at the distal end. The fastener secures a structure in compression between the first head and the external nut. The external nut screws onto the first external thread. The ampoule contains a liquid metal eutectic. The ampoule is insertable into the bore. The internal plug includes a second head, an actuator mechanism, and an auger opposite thereto. The internal plug has a second helical external thread between the second head and the auger for screwing into the bore along the first internal thread. Upon receipt of the signal, the internal plug axially drives the auger towards the proximal end into the ampoule to release the eutectic, thereby fracturing the bolt.

The present invention discloses methods and systems for detecting the tightness state of a bolt or nut under inspection. At least one sensor is mounted on the bolt or nut. At least another sensor is mounted on a structure where the bolt or nut is mounted. Data of motion and/or orientation is acquired. A first angle of the bolt or nut in a plane of rotation of the bolt or nut is calculated. The first angle is related to rotation of the bolt or nut. A second angle of the structure in the plane of rotation of the bolt or nut is calculated. The second angle is unrelated to rotation of the bolt or nut. The initial angle difference between the first and second angles is calculated when the bolt or nut is tight. A subsequent angle difference between the first and second angles is calculated during the inspection. Using the initial angle difference and the subsequent angle difference, the screwed-out angle of the bolt or nut is obtained. Then, the tightness state of the bolt or nut is determined based on the screwed-out angle.