Securing mechanism for rotary assembly wear sleeves

A lock ring for incorporation in a well tool assembly that comprises a tubular shaft and a protective sleeve mounted co-axially on the shaft, the lock ring comprising:

• a generally annular ring body that is configured for co-axial mounting on the shaft and for axial reception in a socket cavity between the protective sleeve and the shaft;
• a screw-thread provided on a radial periphery of the ring body, the screw-thread being configured for screwing engagement with a complementary screw-thread to cause axial advance of the lock ring into the socket cavity;
• and
• a wedging formation defined by the ring body and configured for wedging the lock ring between the protective sleeve and the shaft in response to axial advance of the lock ring into the socket cavity.

A method comprising:

• locating a protective sleeve co-axially on a shaft of a tool assembly, to cover a radially outer surface of the shaft along an axially extending portion of the shaft, the protective sleeve defining a wear surface configured for circumferential sealing engagement with a rotary seal through which the protective sleeve is to extend such as to allow sealing relative rotation between the protective sleeve and the rotary seal;
• locating a lock ring co-axially on the shaft;
• receiving the lock ring in a socket defined between the protective sleeve and the shaft, causing screwing engagement between cooperating screw-threads on the lock ring and the protective sleeve, respectively;
• and
• applying tightening torque to the cooperating screw threads, to increase axial penetration of the lock ring into the socket and cause wedging of the lock ring between the protective sleeve and the shaft, thereby to secure the protective sleeve to the shaft to prevent relative movement between them.