FLEXIBLE SHAFT (VERSIONS) Russian patent published in 2015 - IPC F16C1/02 E21B43/11 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the equipment for oil industry, and is intended for use in the devices for deep perforation of the formations. The flexible shaft containing resilient hose, shell in form of separate cylindrical links with central hole, contacting with each other by end parts by means of the connecting element made out of the interacting links, and core located in the central hole of the links. Under one option each link at the opposite ends is equipped with the connecting element and socket, respectively. The connecting element of each link is made as rectangular shoulder, and socket - in form of slot perpendicular to the shoulder of this link for the analogue shoulder of the contacting link. Under the second option the links are made of two alternating types, one of them are provided at ends with the rectangular installed perpendicular shoulders, and another are provided with sockets made in form of the installed perpendicular slots for the shoulders of the contacting links. The core under both options is made as resilient hose with OD equal to the diameter of the central hole of the link, and is installed in the central hole with longitudinal pre-tension.

EFFECT: shaft return to straight state after bending.

2 cl, 4 dwg