Universal joint

Abstract

A universal joint assembled in a drill string transfers torque between two components where the shafts of the components are not completely aligned. The universal joint includes two members each with pin connections on one end and axially extending arms on the other end. The axially extending arms intermesh when the members are assembled defining a closed cavity between the arms. The cavity retains a ball bearing held between two seats. The universal joint when assembled to portions of the drill string at the pins on each end transfer torque by intermeshing of the teeth. Axial force is transferred through the seats holding the ball bearing.

1 .- 7 . (canceled) 
     
     
         8 . A universal joint for a downhole drill string comprising:
 an upperjoint member with longitudinally extending arms;   a lower joint member with longitudinally extending arms; and   articulating bearing surfaces mounted on each of the arms of the upper and lower joint members, wherein the bearing surfaces bear against each other to transmit torque from the upper joint member to the lower joint member.   
     
     
         9 . The universal joint of  claim 8  where normal vectors to the bearing surfaces are generally aligned on a plane that passes through a pivot point of the universal joint and is perpendicular to the longitudinal axis of one of the upper joint member or the lower joint member. 
     
     
         10 . The universal joint of  claim 8  where the arms of each of the upper and lower joint members each include recesses each of which receive a bearing support, and the bearing surfaces are on the bearing supports to pivot and maintain contact with a corresponding bearing surface on an adjacent arm. 
     
     
         11 . The universal joint of  claim 8  where the universal joint is used to transfer torque from a mud motor to a drill bit. 
     
     
         12 . A method of transferring torque and axial force in a downhole drill string:
 engaging extending arms of a first member with extending arms of a second member;   retaining a ball bearing between bearing faces along longitudinal axes of each of the first member and the second member;   transferring torque between the engaging extending arms; and   transferring axial force through the ball bearing.   
     
     
         13 . The method of  claim 12  including converting eccentric rotation to axial rotation. 
     
     
         14 . The method of  claim 12  including spacing the ball bearing from the extending arms. 
     
     
         15 .- 19 . (canceled) 
     
     
         20 . A universal joint for downhole drill string comprising:
 a first joint member having longitudinally extending arms;   a second joint member having longitudinally extending arms, wherein the first joint member and the second joint member engage each other to transfer torque; and   a bearing assembly coupled to the first joint member and the second joint member, wherein the bearing assembly comprises a housing for receiving therein at least portions of one or more bearing members.   
     
     
         21 . The universal joint of  claim 20 , wherein the housing comprises a tubular body. 
     
     
         22 . The universal joint of  claim 20 , wherein the bearing assembly is axially insertable into the first joint member and the second joint member. 
     
     
         23 . The universal joint of  claim 20 , wherein the one or more bearing members comprise a first bearing member, a second bearing member, and a third bearing member, wherein the first bearing member and the third bearing member pivot about the second bearing member. 
     
     
         24 . The universal joint of  claim 20 , wherein the one or more bearing members comprise a first bearing member and a second bearing member, wherein the first bearing member is coupled to the first joint member, and wherein the second bearing member is coupled to the second joint member. 
     
     
         25 . The universal joint of  claim 20 , wherein the one or more bearing members comprise a bearing member coupled to the longitudinally extending arms of the first joint member. 
     
     
         26 . The universal joint of  claim 20 , wherein the first joint member comprises a body, wherein the longitudinally extending arms of the first joint member extends from the body, and wherein the one or more bearing members comprise a bearing member coupled to the body of the first joint member. 
     
     
         27 . The universal joint of  claim 20 , wherein the one or more bearing members comprise a first bearing member rotating about a second bearing member, and wherein the housing fully encloses the first bearing member and the second bearing member along the longitudinal extensions of the first bearing member and the second bearing member. 
     
     
         28 . The universal joint of  claim 27 , wherein the first bearing member comprises at least one circumferential recess, wherein the first bearing member is coupled to the longitudinally extending arms of the first joint member by at least one fastener, and wherein at least a portion of the at least one fastener is received within the at least one circumferential recess. 
     
     
         29 . The universal joint of  claim 28 , wherein the housing comprises at least one aperture, and wherein the at least one fastener is positioned through the at least one aperture. 
     
     
         30 . The universal joint of  claim 20 , wherein the one or more bearing members comprise a bearing member including a first portion and a second portion that is wider than the first portion. 
     
     
         31 . The universal joint of  claim 30 , wherein the housing comprises a tubular body having an end with a reduced opening diameter such that the first portion of the bearing member is insertable through the end of the housing and extends longitudinally outside the housing while the second portion is retained inside the housing. 
     
     
         32 . The universal joint of  claim 30 , wherein the first portion comprises at least one circumferential recess, wherein the bearing member is coupled to the second joint member by at least one fastener, and wherein at least a portion of the at least one fastener is received within the at least one circumferential recess.