FLEXIBLE SHAFT Russian patent published in 2007 - IPC F16C1/02 E21B43/11 

FIELD: the invention refers to machine building and is designed for using primarily in arrangements for perforation of cased borehole.

SUBSTANCE: the flexible shaft consists out of links connected with each other with the end parts. Each link is fulfilled in the shape of a cylindrical bushing with a central opening. On one of the end parts of the bushing there is a connective element in the shape of two lugs, each of them is of T- profile located in a diametrical plane in opposition to each other. At that the exterior surfaces of the walls are fulfilled together with the exterior ring surface of the cylindrical bushing. The distance between the inner surfaces of the walls is approximately equal to the diameter of the central opening. On the other end part transversely to the diametrical plane of the location of the plug a socket is fulfilled in the shape of a transversal through groove of T- profile oriented with the cut in the shelf into the cylindrical bushing. and with the cut in the wall - to the end face of the bushing. At that the dimensions parameters and also the profile of the groove are fulfilled on condition of placing the lugs in the mentioned groove for securing swing joint of one link with the other. Inside the central opening a core is placed. In quality of a core may be used a hollow tube over which a protective layer in the shape of a spiral is installed. Besides, for securing integrity of the covering and exclusion of a radial displacement of the links relatively to each other, a winding is made over it in the shape of a spiral metallic tape or a counter winding of the mentioned tape in two layers. The invention increases reliability of the work due to provision of reliable connection of the links with each other and excluding damage during the work of the core at simultaneous expansion of operational possibilities due to provision of transfer of significant rotary and longitudinal effort. Provision of various including small radiuses of the bends with creation at perforation of linear perforating channels.

EFFECT: increases reliability of work.

7 cl, 5 dwg