Power swivel for use with concentric pipe strings

Claim 2

A power swivel for dual concentric pipe strings comprising: a. a stationary annular headplate having a central opening; b. a hollow spindle rotatably mounted in said opening and adapted to receive the upper end of a first pipe string; c. hanger means on the headplate for securing thereto a second pipe string extending through the bore of said first pipe string in nonrotative relation thereto; d. a drive ring disposed about said spindle below said headplate for axial and rotational movement relative thereto; e. reversible motor means mounted on the headplate and drivingly connected to said drive ring; f. a drive connection between said drive ring and said spindle including a threaded section affording limited axial movement of the drive ring relative to the spindle in response to relative rotation therebetween; and g. means mounted on said spindle for transmitting torsional force therefrom to said first pipe string.

Claim 3

A power swivel according to claim 1 Including: pipe-gripping elements mounted to said spindle below said means for transmitting torsional force and arranged for radial movement into and out of gripping engagement with said first pipe string in response to said limited axial movement of said drive ring.

Claim 4

A power swivel according to claim 2 wherein said pipe-gripping elements include: a. a plurality of angularly spaced pipe-gripping wedges having radially slidable connection to the lower end of said spindle; and b. a tapered slip bowl mounted to said drive ring in surrounding relation to said wedges.

Claim 5

A power swivel according to claim 1 wherein said drive ring includes: a. an internally toothed ring gear disposed about its outer periphery and meshing with pinions driven by said motor means; and b. a tubular hub surrounding said spindle and a carrying thread section in mesh with a longer thread section on said spindle.

Claim 6

A power swivel according to claim 1 wherein said hanger means includes: a. a tubular hanger body having an annular recess in the bore thereof; b. a connector nipple disposed coaxially through said bore and having an annular lug seatable in said recess; and c. retractable hanger pins threaded radially through said hanger body for movement into and out of locking engagement with said connector nipple.

Claim 7

A power swivel according to claim 1 wherein said last-mentioned means includes: a. arcuate dogs having toothed inner faces and smoothly tapered outer faces rockably mounted in angularly spaced relation in the bore of said spindle; and b. cam surfaces in the bore of said spindle cooperating with said tapered outer faces of said dogs to rock said dogs inTo and out of gripping engagement with said first pipe string in response to angular movement of said spindle.

Claim 8

A power swivel according to claim 1 including means carried by said headplate for separately providing fluid communication with the respective pipe strings.

Claim 9

A power swivel for dual concentric pipe strings comprising: a. a stationary annular headplate having a central opening; b. a hollow spindle vertically disposed for rotation in said opening and adapted to receive the upper end of a first pipe string; c. a drive ring disposed about said spindle below said headplate for axial and rotational movement relative thereto; d. motor means mounted on the headplate and drivingly connected to said drive ring; e. means mounted in the bore of said spindle for transmitting torsion therefrom to said first pipe string; f. a drive connection between said drive ring and said spindle including a threaded section affording limited axial movement of the drive ring relative to the spindle; g. pipe-gripping elements mounted to said spindle below said torsion-transmitting means for radial movement into an out of gripping engagement with said first pipe string in response to said limited axial movement of said drive ring; and h. hanger means on the headplate for securing thereto a second pipe string extending through the bore of said first pipe string.

Claim 10

A power swivel for dual concentric pipe strings comprising: a. a stationary annular headplate having a central opening; b. a hollow spindle vertically disposed for rotation in said opening and adapted to receive the upper end of a first pipe string; c. a drive ring disposed about said spindle below said headplate for axial and rotational movement relative thereto; d. motor means mounted on the headplate and drivingly connected to said drive ring; e. means mounted in the bore of said spindle for transmitting torsion therefrom to said first pipe string; f. a drive connection between said drive ring and said spindle including a threaded section affording limited axial movement of the drive ring relative to the spindle; g. pipe-gripping elements mounted to said spindle below said torsion-transmitting means for radial movement into an out of gripping engagement with said first pipe string in response to said limited axial movement of said drive ring; and h. hanger means on the headplate for securing thereto a second pipe string extending through the bore of said first pipe string.

Claim 11

A power swivel according to claim 8 including means carried by said headplate for separately providing fluid communication with the respective pipe strings.

Claim 12

A power swivel for dual concentric pipe strings comprising: a. a stationary annular headplate having a central opening; b. a tubular spindle vertically disposed for rotation in said opening and adapted to receive the upper end of a first pipe string; c. means mounted in the bore of said spindle for transmitting torsion therefrom to said first pipe string; d. a drive ring disposed below said headplate surrounding the spindle for axial and rotational movement relative to said headplate; e. complementary thread means connecting said drive ring to said spindle for limited vertical movement relative thereto in response to rotational movement of the drive ring; f. motor means mounted on the headplate and drivingly connected to said drive rings; g. a downwardly tapering slip bowl depending from said drive ring; h. a plurality of pipe-gripping wedges mounted to said spindle and extending into said slip bowl for radial movement into and out of gripping engagement with said first pipe string in response to axial movements of said slip bowl; i. hanger means on the headplate for securing thereto a second pipe string extending through the bore of the first pipe string; and j. means carried by said head plate for separately providing fluid communication with each of said pipe strings.

Claim 13

A power swivel for dual concentric pipe strings comprising: a. a stationary annular headplate having a central opening; b. a tubular spindle vertically disposed for rotation in said opening and adapted to receive the upper end of a first pipe string; c. means mounted in the bore of said spindle for transmitting torsion therefrom to said first pipe string; d. a drive ring disposed below said headplate surrounding the spindle for axial and rotational movement relative to said headplate; e. complementary thread means connecting said drive ring to said spindle for limited vertical movement relative thereto in response to rotational movement of the drive ring; f. motor means mounted on the headplate and drivingly connected to said drive rings; g. a downwardly tapering slip bowl depending from said drive ring; h. a plurality of pipe-gripping wedges mounted to said spindle and extending into said slip bowl for radial movement into and out of gripping engagement with said first pipe string in response to axial movements of said slip bowl; i. hanger means on the headplate for securing thereto a second pipe string extending through the bore of the first pipe string; and j. means carried by said head plate for separately providing fluid communication with each of said pipe strings.