A shear nut 10, a lock nut 62 (together forming a nut arrangement 60 for a bolt 12), and a driver (110, 500, 600, 700) used while installing the nut arrangement 60. Particularly, the bolt 12 is a rock bolt. The shear nut 10 comprises first and second portions (14, 18) connected by a connecting portion 22. The second portion 18 comprises an engaging formation 20 configured to interact with the bolt 12 to limit the extent to which the second portion 18 operatively advances axially along the bolt 12. The first portion 14 has an internal thread. In use, the first and second portions (14, 18) are configured to become separated at the connecting portion 22, when the engaging formation 20 interacts with the bolt 12 and a predetermined moment is applied to the first portion 14.

A shear nut 10, a lock nut 62 (together forming a nut arrangement 60 for a bolt 12), and a driver (110, 500, 600, 700) used while installing the nut arrangement 60. Particularly, the bolt 12 is a rock bolt. The shear nut 10 comprises first and second portions (14, 18) connected by a connecting portion 22. The second portion 18 comprises an engaging formation 20 configured to interact with the bolt 12 to limit the extent to which the second portion 18 operatively advances axially along the bolt 12. The first portion 14 has an internal thread. In use, the first and second portions (14, 18) are configured to become separated at the connecting portion 22, when the engaging formation 20 interacts with the bolt 12 and a predetermined moment is applied to the first portion 14.

The invention provides a locknut having a nut body having a threaded portion with an internal thread, an adjacent perimetral shoulder and a collar surrounding the shoulder, and having a metal annular washer, the annular washer resting on the shoulder within the collar and the collar being bent inwardly to form an annular groove between the bent collar and the shoulder in which the annular washer is received. An internal thread corresponding to the internal thread of the threaded portion of the nut body is formed at the inner perimeter of the annular washer, and the internal thread of the annular washer is offset axially by a distance with respect to the internal thread of the nut body. For better fixing of the annular washer in the annular groove, a row of projections or recesses is formed on the shoulder or on the annular washer where the annular washer and the shoulder overlap, which projections or recesses project in the axial direction and are arranged distributed around the perimeter of the shoulder or the annular washer. The projections form bearing surfaces, lines or points for the annular washer on the shoulder when the annular washer is placed inside the collar on the shoulder of the nut body. When the collar is deformed to form the annular groove, an axial force is applied to the annular washer, partially deforming the projections or recesses and/or partially pressing them into the opposite surface of the annular washer or the shoulder. As a result, the annular washer is held in the annular groove in a force-locking and form-fitting manner.

The invention provides a locknut having a nut body having a threaded portion with an internal thread, an adjacent perimetral shoulder and a collar surrounding the shoulder, and having a metal annular washer, the annular washer resting on the shoulder within the collar and the collar being bent inwardly to form an annular groove between the bent collar and the shoulder in which the annular washer is received. An internal thread corresponding to the internal thread of the threaded portion of the nut body is formed at the inner perimeter of the annular washer, and the internal thread of the annular washer is offset axially by a distance with respect to the internal thread of the nut body. For better fixing of the annular washer in the annular groove, a row of projections or recesses is formed on the shoulder or on the annular washer where the annular washer and the shoulder overlap, which projections or recesses project in the axial direction and are arranged distributed around the perimeter of the shoulder or the annular washer. The projections form bearing surfaces, lines or points for the annular washer on the shoulder when the annular washer is placed inside the collar on the shoulder of the nut body. When the collar is deformed to form the annular groove, an axial force is applied to the annular washer, partially deforming the projections or recesses and/or partially pressing them into the opposite surface of the annular washer or the shoulder. As a result, the annular washer is held in the annular groove in a force-locking and form-fitting manner.

A dual-threaded screw structure having two kinds of threads formed on a shank, namely, a first thread consisting of one or more threads and a second thread having a lead larger than a lead of the first thread is provided herein. The claimed configuration has a beneficial effect of preventing looseness when the screw structure is fastened with double nuts. One embodiment of the present invention exhibits an example of a dual-threaded screw structure, in which a root diameter between the ridges of the hill-like second thread ridges is formed to be larger by 10% of a height of the ridges than an effective diameter of a first thread. In this case, an inner diameter of an internal thread of a second nut for preventing looseness is formed to be larger than the effective diameter of the first thread by 10% of the height of the ridges.

A locknut which uses a pivotable segment mounted within the locknut body to slightly deflect producing an increased friction (locking force) between the locknut body and bolt which is threaded into the locknut body. This locking force is preset at the construction of the locknut to assume a lower amount of force or a higher amount of force according to the desires of the customer purchasing the locknut. The amount of force could be adjustable by using a set screw.

A locknut which uses a pivotable segment mounted within the locknut body to slightly deflect producing an increased friction (locking force) between the locknut body and bolt which is threaded into the locknut body. This locking force is preset at the construction of the locknut to assume a lower amount of force or a higher amount of force according to the desires of the customer purchasing the locknut. The amount of force could be adjustable by using a set screw.

An assembly for a coupling together rotatable components according to an example of the present disclosure includes, among other things, a rotor shaft extending along a centerline axis, the rotor shaft defining an inner bore extending from an axial end of the rotor shaft, a gear mounted on an outer diameter of the rotor shaft, a lock nut threadedly engaged with the outer diameter of the rotor shaft such that the lock nut abuts against an axial end face of the gear, and a retainer including a step portion extending from a head portion and including a projection portion extending from the step portion. The projection portion is insertable into the inner bore to bias the lock nut against the axial end face of the gear, and the step portion is dimensioned to establish an interference fit with the rotor shaft along the inner bore. A starter assembly and a method of assembly are also disclosed.

An assembly for a coupling together rotatable components according to an example of the present disclosure includes, among other things, a rotor shaft extending along a centerline axis, the rotor shaft defining an inner bore extending from an axial end of the rotor shaft, a gear mounted on an outer diameter of the rotor shaft, a lock nut threadedly engaged with the outer diameter of the rotor shaft such that the lock nut abuts against an axial end face of the gear, and a retainer including a step portion extending from a head portion and including a projection portion extending from the step portion. The projection portion is insertable into the inner bore to bias the lock nut against the axial end face of the gear, and the step portion is dimensioned to establish an interference fit with the rotor shaft along the inner bore. A starter assembly and a method of assembly are also disclosed.

An anti-loosening fastener, including a key-bolt-receiving bolt, including a head section to receive at least one tool thereon, a rear cylindrical section disposed on at least a portion of the head section to extend a predetermined distance away from the head section, the rear cylindrical section including a key-bolt-receiving aperture disposed within at least a portion of the rear cylindrical section to receive an external fastener therein, and an internal thread section circumferentially disposed on an inner surface within the key-bolt-receiving aperture, and a key bolt to removably connect to at least a portion of the key-bolt-receiving bolt.