GB2209983A

GB2209983A - Portable machining assembly

Info

Publication number: GB2209983A
Application number: GB8721932A
Authority: GB
Inventors: Stewart Robb
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-09-17
Filing date: 1987-09-17
Publication date: 1989-06-01
Anticipated expiration: 2007-09-17
Also published as: GB2209983B; GB8721932D0

Abstract

A portably machining assembly comprises a clamping region in the form of an open-ended cylinder (2) having hydraulically operated clamping jaws (4) engaged with the external surface (5) of piping. A machining region is in the form of an open squirrel-cage having axially extending bars (10) spaced apart circumferentially. A cylindrical housing comprises a cylinder (11) with formations slidably interengaging (at 14) with the bars (10). The cylindrical housing carries a rotary body (26) with a tool holder (27) radially movably thereon. A lead-screw (22) is provided for axial motion of the cylindrical housing. <IMAGE>

Description

PORTABLE MACHINING ASSEMBLY Description The present invention relates to a portable machining assembly primarily intended for machining the tapered internal and'external screw-threaded end connections of all kinds of piping used in the drilling and production phases of oil and gas wells.

The current method of machining such end connections involves installing the piping in a machining plant and turning the piping relative to a tool which tracks longitudinally and radially of the piping according to the desired tapered threaded profile. This has the disadvantage, particularly when the end connections are being re-machined after extended use, that the piping requires to be removed from the vicinity of its point of use to the machining plant.

An object of the invention is to obviate or mitigate that disadvantage.

According to the invention there is provided a portable machining assembly comprising a first hollow elongate substantially cylindrical housing having a clamping region extending from one open end which can be slid over an end of a length of piping, clamping means being provided in the clamping region to engage with the external surface of the length of piping for positioning the first housing coaxially with the length of piping, the housing also having a machining region extending from the clamping region and being of an open squirrel-cage form having axially extending bars spaced apart circumferentially and terminating in an end plate remote from the clamping region, a second cylindrical housing within the machining region of the first housing, slidably interengaging formations being provided on the inner sides of the bars and the outer surface of the second housing for permitting movement of the second housing in only a direction along the axis of the first housing, a hollow spindle I, journalled for rotation within the second housing about the axis of the first housing and movable with the second housing along that axis, a motor mounted on the second housing so as to be movable with the latter alongside and between adjacent bars, the motor having a drive shaft which is drivingly connected with the hollow spindle, a gearbox mounted on the end plate and having an input shaft in relatively slidable, splined coaxial driving connection with the drive shaft of the motor, the gearbox also having as an output shaft a lead-screw extending coaxially into the hollow spindle from the end plate, a nut device mounted on the end of the second housing nearer to the end plate adapted releasably to engage with the lead-screw for axial motion of the second housing, and a machining head having a fixed body mounted on the opposite end of the second housing, an arbor extending from one side of the fixed body and drivingly engaging into the hollow spindle, a rotary body extending from the other side of the fixed body and drivingly connected with the arbor, and a tool holder movable radially on the rotary body.

Using the invention, the piping can be machined or re-machined in the vicinity of its point of use, thus reducing the cost of transportation of the piping.

An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawing showing generally in axial section, a portable machining assembly fitted to an end of a length of piping.

In the drawing the male end of a length of piping is shown, the tapered threaded profile of the end being indicated by the reference numeral 1. A first hollow elongate substantially cylindrical housing comprises a clamping region in the form of an open-ended cylinder 2 having a connection flange 3 at one end. Clamping means are provided in the form of twelve hydrautically-operated jaws 4 engageable with the external surface 5 of the piping and spaced apart axially and circumferentially.

The first hollow elongate substantially cylindrical housing also comprises a machining region in the form of an open squirrel-cage having an end flange 6 bolted at 7 and spigoted at 8 to the flange 3. The machining region also comprises an end plate 9 interconnected with the flange 6 by fo#r axially-extending bars 10 spaced apart circumferentially A second cylindrical housing is disposed within the machining region. This comprises a hollow open-ended cylinder 11 and end plates 12 and 13 with central openings.

Slidably interengaging formations 14 are provided on the inner sides of the bars 10 and the outer surfaces of the cylinder 11 and end plates 12 and 13 for permitting movement of the second housing in only a direction along the axis of the first housing. A hollow spindle 15 is journalled for rotation within the second housing about the axis of the first housing and is movable with the second housing along that axis. A hydraulic motor 16 is mounted on the cylinder 11 so as to be movable with the second housing alongside and between adjacent bars 10.

The motor 16 has a drive shaft 17 which is drivingly connected with the hollow spindle 15 by intermeshing gear wheels 18 and 19.

A gearbox 20 is mounted on the end plate 9 and has an input shaft 21 in relatively slidable, splined coaxial driving connection with the drive shaft 17. In this embodiment the shaft 17 is slidable over the shaft 21. The gearbox 20 also has as an output shaft a lead-screw 22 extending coaxially into the hollow spindle 15 from the end plate 9. A nut device 23 is mounted on the end plate 13 and is hydraulically operable releasably to engage with the lead-screw 22 for axial motion of the second housing.

A machining head has a fixed body 24 mounted on the end plate 12. An arbor 25 extends from one side of the fixed body 24 and drivingly engages into the hollow spindle 15. A rotary body 26 extends from the other side of the fixed body and is drivingly connected with the arbor 25. A tool holder 27 is radially movable on the rotary body 26.

The gearbox 20 can be a commercially available numerical control gearbox having one or more output shafts.

The machining head can also be a commercially available item. On example of such an item is that known as the D'Andrea 1-CENTER numerical facing head with a radial feed numerical control unit 28 disposed off-centre and movable alongside and between adjacent bars 10 but remote from the motor 16.

The clamping jaws 4 are controlled to align the axis of the first housing with the axis of the length of piping and the nut device 23 is under an indexing control.

In use, the hydraulic motor 16 is operated to turn the hollow spindle 15, the arbor 25, the rotary body 26 and the tool holder 27. The lead-screw 22 is also turned and the nut device 23 engaged therewith so as to cause axial feed movement of the tool holder 27. Radial movement of the tool holder 27 is controlled by the unit 28 and all three movements are controlled to produce the desired tapered threaded profile of the end 1.

The same operation could also be carried out within female end of a length of piping.

Instead of the hydraulic motor 16 a pneumatic motor or an electric motor may be used dependent upon the power sources available at the point of use.

Claims

1. A portable machining assembly comprising a first hollow elongate substantially cylindrical housing having a clamping region extending from one open end which can be slid over an end of a length of piping, clamping means being provided in the clamping region to engage with the external surface of the length of piping for positioning the first housing coaxially with the length of piping, the housing also having a machining region extending from the clamping region and have axially extending guides spaced apart circumferentially, a second cylindrical housing within the machining region of the first housing, formations being provided on the outer surface of the second housing and slidably engaging with the guides for permitting movement of the second housing in only a direction along the axis of the first housing, a leadscrew, a nut device mounted on the second housing and engaging with the lead-screw for axial motion of the second housing, and a machining head mounted on the end of the second housing facing the clamping region and comprising a rotary body rotatable about the axis of the first housing and a tool holder movable radially on the rotary body.

2. An assembly according to claim 1, wherein the machining region is of an open squirrel-cage form having axially extending bars forming the guides and the second housing carries a motor which is movable between adjacent bars together with a drive transmission from the motor to the rotary body.

3. An assembly according to claim 2, wherein the leadscrew is journalled in an end plate of the squirrel cage remote from the clamping region and is driven by means mounted on the end plate.

4. A portable machining assembly substantially as hereinbefore described with reference to the accompanying drawings.