US Patent 10060466 Fastening device and hook part

A hook part includes a hook main body; a latch for closing the hook main body; and a shaft to which the base end of the latch is integrally coupled, the shaft extending away from the hook main body along the rotational axis such that coupling between the attachment part and the hook part is ensured. A latch includes a spring portion provided closer to the base end of the latch; and a latch main body coupled with the coupled portion via the spring portion. The spring portion is elastically configured to enable urging of the latch away from the hook main body. The connection point of the latch and the shaft is farther from the hook main body along the rotational axis than the connection point of the hook main body and the coupled portion.