A method for manufacturing washer includes steps of providing a wire material, deforming part of the wire material to be a ring shape, cutting off the part in the ring shape to obtain a ring-shaped wire material, and forging the ring-shaped wire material into a washer having a split defined by end surfaces at two opposite ends of the ring-shaped wire material.

A contact ring including a ring-shaped structure formed of an electrically conductive material. The ring-shaped structure has a plurality of projections on at least one side and a plurality of blades on at least one side. The projections and the blades penetrate an electrically insulating surface layer of each of a pair of contact elements and contact an electrically conductive material of each of the contact elements to electrically connect the contact elements.

A fastener assembly is provided. The fastener assembly includes a nut having an internally threaded portion and an annulus extending from the nut and configured for receiving the shank of an elongate fastener. A compression collar is configured for deflecting the annulus into at least one of fixed engagement with the shank or to impart a spring bias of the annulus against the compression collar upon tightening of the nut about a working surface.

A coupling mechanism is provided for coupling a supporting element to a frame, and includes a base member and a C-shaped retainer. The frame includes a frame body and a leg member that has a leg body extending downwardly from the frame body to terminate at an enlarged leg end. The base member defines therein a recess for the enlarged leg end therein. The supporting element is coupled to a lower major surface of the base wall. The C-shaped retainer extends to be disposed about the leg body, and is configured to be detachably coupled to a surrounding wall of the base member for retaining the enlarged leg end in the recess.

A fastening system includes a first fastening element attachable to a structure and which has a base portion for plugging through a structural opening, a second fastening element, and a plastically deformable funnel element. The funnel element has a funnel-like basic shape with a funnel opening. The second fastening element can be introduced through the funnel opening into a receiving opening of the base portion and fastened therein and has a collar which faces away from the receiving opening and which is larger than the funnel opening. The funnel element is designed to be deformed from the funnel-like basic shape into a flat, disk-like final shape by the collar of the second fastening element during the fastening of the second fastening element.

A contact ring including a ring-shaped structure formed of an electrically conductive material. The ring-shaped structure has a plurality of projections on at least one side and a plurality of blades on at least one side. The projections and the blades penetrate an electrically insulating surface layer of each of a pair of contact elements and contact an electrically conductive material of each of the contact elements to electrically connect the contact elements.

An anti-loosening bolt and nut assembly structure includes a bolt having a bolt head and a bolt shank, two elastic washers, and a nut. The two elastic washers are sleeved on the bolt shank. The two elastic washers are matched with the bolt head and the nut, respectively. Each elastic washer includes an annular body having an opening. A bottom of the annular body is provided with anti-slip teeth. A top of the annular body extends upward to form an anti-loosening ring. An outer inclined surface is formed on an outer side of the anti-loosening ring. The anti-loosening ring is provided with a plurality of first unidirectional teeth. The bolt head and the nut each includes a unidirectional anti-loosening device matched with the first unidirectional teeth.

A self-reacting center wheel nut assembly includes a reaction ring (120) formed between a center wheel nut (110) and a lock collar assembly (130). The self-reacting center wheel nut assembly may also include a washer (140) and O-rings. The self-reacting center wheel nut assembly improves and simplifies wheel bolt tightening; uses the lock collar assembly as a reaction point by transferring opposing torque generated during installation and removal through the reaction ring, which is reacted on by a dual sleeved drive assembly; may be used with HYTORC electric battery powered torque multiplier gun/tools to deliver quick, accurate and precise torque; eliminates the need for external reaction points such as the rim or ground, thereby eliminating side loads and damage to the wheel; is fully sealed and lubricated; eliminates vehicle movement and the need to lock the brakes; reduces operator fatigue, chances of injury and saves operator time and energy.

The two lockable stainless and lossless screw pairs at two ends of the bolt are provided both to avoid screw pairs stained or destroyed by strain force from loading and to decrease the cost because of energy consumption in traditional process of bolt or its cost from environmental pollution.

A loose-proof screw assembly comprises a screw (1) having a head (11) and a shaft (12) and an elastic washer (2) having a central hole (21). The shaft (12) comprises a smooth portion (121) without threads and a threaded portion (122) with threads. The threaded portion (122) is adapted to be screwed into a threaded hole (201) of a base (200) through a through hole (101) of a part (100) to be fixed and the central hole (21) of the elastic washer (2), so as to fasten the part (100) to be fixed onto the base (200). The elastic washer (2) is disposed between the part (100) to be fixed and the base (200), and forms interference fit with the smooth portion (121). A fastened structure is also included. According to the structure described above, loose of screw connection due to vibration or the like can be reliably prevented.