BEARING APPARATUS AND METHODS

1 . An apparatus, comprising:

a first housing defining an opening; and

a bearing housing disposed in the opening so that movement of at least a portion of the bearing housing within the first housing and along a first axis is permitted, the bearing housing defining first and second bearing surfaces, the first and second bearing surfaces being spaced apart along a second axis to prevent movement of the bearing housing within the first housing and along the second axis, the second axis being perpendicular to the first axis.

2 . The apparatus of claim 1 , wherein the bearing housing is at least substantially annular in shape and defines an outside diameter;

wherein the opening is at least substantially cylindrical in shape, and defines a center and an inside diameter of the first housing that passes through the center, the inside diameter of the first housing being greater than the outside diameter of the bearing housing;

wherein the first axis extends radially through the center; and

wherein the second axis extends longitudinally through the center.

3 . The apparatus of claim 2 , wherein the difference between the outside diameter and the inside diameter limits the range of movement of the bearing housing within the first housing and along the first axis.

4 . The apparatus of claim 1 , further comprising a compressible element disposed in the opening and between an outside surface of the bearing housing and an inside surface of the first housing that is defined by the opening.

5 . The apparatus of claim 4 , wherein the compressible element is coupled to the bearing housing and compresses in response to movement of the bearing housing within the first housing and along the first axis.

6 . The apparatus of claim 1 , further comprising a first flat bearing and a second flat bearing defining a third bearing surface and a fourth bearing surface, respectively;

wherein the first and the second flat bearings are spaced along the second axis; and

wherein the third and the fourth bearing surfaces engage the first and the second bearing surfaces, respectively, to prevent movement of the bearing housing within the first housing and along the second axis.

7 . The apparatus of claim 1 , further comprising:

a first tubular member around which the bearing housing circumferentially extends;

a second tubular member spaced from the first tubular member along the second axis; and

a third tubular member coupled to at least one of the first and the second tubular members and extending between the first and the second tubular members;

wherein movement of the bearing housing within the first housing and along the first axis reduces any bending moment experienced by the third tubular member.

8 . The apparatus of claim 7 , wherein the third tubular member is coupled to the second tubular member;

wherein the apparatus further comprises a fourth tubular member coupled to the first tubular member and extending between the first and the third tubular member, the fourth tubular member comprising an opposing first and a second end portion; and

wherein movement of the bearing housing within the first housing and along the first axis reduces any bending moment experienced by the fourth tubular member.

9 . The apparatus of claim 8 , wherein the first, second, and third tubular members define a first, a second, and a third internal passage, respectively;

wherein the first end portion of the fourth tubular member extends within the first internal passage and at least the second end portion of the fourth tubular member extends within the third internal passage; and

wherein at least a portion of the third tubular member extends within the second internal passage.

10 . The apparatus of claim 9 , further comprising:

a top drive; and

a quill operably coupled to the top drive;

wherein the second tubular member is part of the quill, the third tubular member is a sleeve of the top drive, and the fourth tubular member is a piston of the top drive.

11 . The apparatus of claim 1 , further comprising a radial bearing disposed in the bearing housing, the radial bearing comprising:

a first ring to engage a tubular member; and

a second ring engaged with the bearing housing, the second ring extending circumferentially about, and spaced along the first axis from, the first ring.

12 . The apparatus of claim 6 , further comprising a radial bearing disposed in the bearing housing, the radial bearing comprising:

a first ring to engage a tubular member; and

a second ring engaged with the bearing housing, the second ring extending circumferentially about, and spaced along the first axis from, the first ring;

wherein the first flat bearing and the second flat bearing are generally annular in shape and define an inside diameter; and

wherein the inside diameter of the first flat bearing and the second flat bearing are greater than or equals to a diameter of the second ring.

13 . The apparatus of claim 12 , wherein the radial bearing is disposed in the bearing housing between the first bearing surface and the second bearing surface.

14 . A method, comprising:

disposing a bearing housing in an opening defined by a first housing;

permitting movement of the bearing housing within the first housing and along a first axis; and

preventing movement of the bearing housing within the first housing and along a second axis, the second axis being perpendicular to the first axis.

15 . The method of claim 14 , wherein the bearing housing is generally annular in shape and defines an outside diameter;

wherein the opening is generally cylindrical in shape, and defines a center and an inside diameter of the first housing that passes through the center, the inside diameter of the first housing being greater than the outside diameter of the bearing housing;

wherein the first axis extends radially through the center; and

wherein the second axis extends longitudinally through the center.

16 . The method of claim 15 , wherein the difference between the outside diameter and the inside diameter limits the range of movement of the bearing housing within the first housing and along the first axis.

17 . The method of claim 14 , wherein the bearing housing moves in a first direction along the first axis; and

wherein the method further comprises urging the bearing housing to move in a second opposite direction along the first axis in response to the movement of the bearing housing in the first direction along the first axis.

18 . The method of claim 14 , wherein preventing movement of the bearing housing within the first housing and along the second axis comprises engaging a first flat bearing and a second flat bearing against the bearing housing, the first flat bearing and the second flat bearing being spaced along the second axis.

19 . The method of claim 14 , further comprising:

employing the bearing housing to rotatably support the first tubular member;

spacing a second tubular member from the first tubular member along the second axis; and

coupling a third tubular member to at least one of the first and second tubular members so that the third tubular member extends between the first and second tubular members;

wherein movement of the bearing housing within the first housing and along the first axis reduces any bending moment experienced by the third tubular member.

20 . The method of claim 19 , further comprising coupling a fourth tubular member to at least one of the first and third tubular members so that the fourth tubular member extends between the first and third tubular members;

wherein movement of the bearing housing within the first housing and along the first axis reduces any bending moment experienced by the fourth tubular member.

21 . The method of claim 20 , wherein the first, second, and third tubular members define first, second and third internal passages, respectively;

wherein the first end portion of the fourth tubular member extends within the first internal passage and at least the second end portion of the fourth tubular member extends within the third internal passage; and

wherein at least a portion of the third tubular member extends within the second internal passage.

22 . The method of claim 21 , wherein the second tubular member is part of a quill operably coupled to a top drive, the third tubular member is a sleeve of the top drive, and the fourth tubular member is a piston of the top drive.

23 . The method of claim 18 , wherein employing the bearing housing to rotatably support the first tubular member comprises disposing a radial bearing coupled to the first tubular member in the bearing housing, the radial bearing comprising:

a first ring to engage the first tubular member; and

a second ring engaged with the bearing housing, the second ring extending circumferentially about, and spaced along the first axis from, the first ring;

wherein the first flat bearing and the second flat bearing are generally annular in shape and define an inside diameter; and

wherein the inside diameter of the first flat bearing and the second flat bearing is greater than or equals to a diameter of the second ring.

24 . A method, comprising:

spacing apart first and second tubular members;

coupling a third tubular member to each of the first and second tubular members so that the third tubular member extends therebetween;

rotatably supporting each of the first and second tubular members; and

reducing any bending moment experienced by the third tubular member while rotatably supporting each of the first and second tubular members.

25 . The method of claim 24 , wherein the first, second, and third tubular members extend longitudinally along a first axis;

wherein rotatably supporting each of the first and second tubular members comprises:

disposing a bearing housing in an opening defined by a first housing; and

extending the first tubular member within the opening so that the bearing housing circumferentially extends around the first tubular member; and

wherein reducing any bending moment experienced by the third tubular member during rotatably supporting each of the first and second tubular members comprises:

permitting movement of the bearing housing within the first housing and along a second axis that is perpendicular to the first axis; and

preventing movement of the bearing housing within the first housing and along the first axis.

26 . The method of claim 25 , wherein the bearing housing moves in a first direction along the second axis; and

wherein the method further comprises urging the bearing housing to move in a second direction along the second axis in response to the movement of the bearing housing in the first direction along the second axis, the second direction being opposite to the first direction.

27 . The method of claim 25 , wherein the second tubular member is part of a quill operably coupled to a top drive, and the third tubular member is one of a sleeve and a piston associated with the top drive.