Patent ID: 6997811

Claim:
A coupling assembly for connecting, as an axially serial continuation, a down hole motor rotor to an output shaft of the down hole motor, the coupling assembly comprising: a) a first flexible coupling, having a first lubricant space therein, arranged for connection, at a first end, to the output shaft and connected at a second end to a second flexible coupling; b) said second flexible coupling, having a second lubricant space therein, arranged for connection at a third end to the first coupling end, at a fourth end for connection to the motor rotor; c) a first flexible seal situated in the first flexible coupling, arranged to function as a closure for said first lubricant space, the seal comprising a first metal sleeve sealingly and peripherally attached to one end of the first coupling, a first elastomer sleeve sealingly and peripherally attached at one end to the inside surface of the distal end of the first metal sleeve and sealingly and peripherally attached at the other end to the other end of the first flexible coupling; d) a second flexible seal situated in the second flexible coupling, arranged to function as a closure for said second lubricant space, the seal comprising a second metal sleeve sealingly and peripherally attached to one end of the second coupling, a second elastomer sleeve peripherally attached at one end to the inside surface of the distal end of the second metal sleeve and sealingly and peripherally attached at the other end to the other end of the second flexible coupling; and e) at least one variable volume lubricant reservoir in the assembly and arranged with fluid channels to provide lubricant to at least one of said first and said second lubricant spaces.