WO1999042248A1

WO1999042248A1 - Apparatus for conditioning surfaces of an object

Info

Publication number: WO1999042248A1
Application number: PCT/GB1999/000355
Authority: WO
Inventors: Wayne Edmund Dinsdale
Original assignee: Dipt Limited
Priority date: 1998-02-20
Filing date: 1999-02-19
Publication date: 1999-08-26
Also published as: GB9803483D0; AU2528099A

Abstract

The apparatus is used to grind, polish or clean etc. the surfaces of a cylindrical object such as a pipe. A main body (1) has at least two rotary shafts (5) which receive machining tools (22, 23, 24) such as, for example, grinding wheels. Compressed air driven motors (4) contained within rotatable housings in the main body (1) drive the rotary shafts (5) in rotation. The rotary shafts (5) are each eccentrically mounted in the housings (13) so that rotation of the housings alters the distance between centres of the rotary shafts (5). This enables various different tasks to be performed on a work-piece. In use the main body (1) rotates relative to the drive so that the tools (22, 23, 24) orbit around the pipe as they condition the surface. The main body (1) may be separated from the main motor drive (2) so as to be used to condition simultaneously the opposite surfaces of a pipe wall.

Description

1

APPARATUS FOR CONDITIONING SURFACES OF AN OBJECT

The present invention relates to apparatus for conditioning the surfaces of an object particularly, but not exclusively, the surfaces of cylinder such as a pipe.

When a metallic pipe is to be joined to another pipe or other component by means of a weld or the like it is generally necessary to condition the internal and/or external surface of the pipe both prior to and after the joining operation is performed. Most importantly, it is necessary to clean the surfaces at the region where the join is to be made in order to remove dirt and oxidation that may have a detrimental effect on the quality of the weld. It may also be necessary to prepare the ends to be joined by removing sharp edges or by fine machining of the ends to facilitate the welding process. After the weld has been formed it is often necessary to remove any weld material that projects from the surface of the pipe by grinding and polishing.

The term "conditioning" is used herein to refer to treatments including grinding, polishing, deburring, rust or scale removal, chamfering, facing and undercutting. Such operations are conventionally performed manually by using abrasive paper or board or, alternatively, by using a hand-held power tool having an elongate circulating abrasive belt or a rotating abrasive disc. Both the above mentioned techniques require significant effort and are time consuming particularly when both the internal and external surfaces of each pipe require conditioning before and after welding. In certain applications such as the construction, servicing or maintenance of industrial boilers large volumes of pipe have to be conditioned and the task is labour intensive. Moreover it is often difficult to condition effectively certain pipes in-situ in circumstances where access is restricted.

It is an object of the present invention to obviate or mitigate the aforesaid disadvantages.

According to the present invention there is provided apparatus for conditioning surfaces of an object, the apparatus comprising a main body having at least two rotary members, each member having means for engaging a machining tool, and first drive means for driving the rotary members in rotation, wherein at least one of the rotary members is eccentrically mounted in a rotatable housing such that the housing may be rotated to alter the distance between centres of rotation of the rotary members.

Preferably the means for engaging a machining tool is releasable.

Preferably the housings are biased into a position in which the distance between the centres of the rotary members is at a minimum.

The rotary members are preferably shafts but could take other forms such as rotating chucks that have apertures for receiving the machine tools

Each housing preferably houses the first drive means which may be a motor that drives a respective rotary member. A locking element may be provided to lock the housings in a selected position. The locking element may be a disc that is locked to the main body to prevent rotation of the housing relative thereto.

The main body may be detachably connected to a second drive member that rotates the main body. The second drive member is preferably a motor.

There may be provided a pilot shaft that is central to the main body. In a preferred embodiment the pilot shaft is tubular and has at least one aperture that receives part of a machining tool.

The main body may conveniently be provided with one or more rollers that, in use, support the head on a work-piece.

The first drive means are preferably air driven motors. A throttle for supplying compressed air to the motors is preferably mounted on a side of second drive member.

Specific embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a perspective view of pipe conditioning apparatus shown with three alternative machine tool attachments;

Figure 2 is a sectioned view of a main body of the apparatus of figure 1;

Figure 3 is an end view of the main body in the direction of arrow X of figure 2;

Figures 4a to 4m are diagrammatic representations showing thirteen different uses of the apparatus of figures 1 to 3 in a first mode of operation; Figures 5 to 7 are diagrammatic representation of further uses of the apparatus in a first mode of operation;

Figure 8 shows plan and end views of a work-piece being conditioned by the apparatus of figures 1 to 3 ( represented diagrammatically for clarity);

Figure 9 shows an end view of the apparatus of figures 1 to 3 being used to in a second mode of operation to condition a pipe;

Figure 10 is a side sectioned view of the apparatus and pipe of figure 9; and

Figure 11 is a side section view of a pipe containing the apparatus of figures 1 to 3, the apparatus being used in a third mode of operation;

Figure 12 is an end view of the pipe and apparatus of figure 11.

Figure 13 illustrates the apparatus being used on an non-cylindrical surface;

Figure 14 illustrates the apparatus being used to mill bores into an object;

Figure 15 illustrates and shows the apparatus fitted with a pilot member and a grinding disc;

Figure 16 shows front and side views of an alternative main body assembly of the apparatus of the present invention;

Figure 17 is a diagrammatic sectioned representation of the apparatus of figure 16 being used to condition inner, outer and end surfaces of a cylinder simultaneously;

Figure 18 is a diagrammatic sectioned representation of the apparatus of figure 16 being used with a pilot member to polish internal and external surfaces of a tube; and

Figure 19 is a diagrammatic sectioned representation of the apparatus of figure 16 being used with a slotted pilot member.

Referring now to figures 1 to 3 of the drawings, the exemplary apparatus for conditioning pipes has a main body (indicated generally by reference numeral 1 ) that is rotatably connected to a drive motor 2 via a sleeve 3.

The main body 1 comprises a retaining structure that houses two compressed air motors 4 each of which drives a rotary shaft 5. The retaining structure comprises two plates 6a, 6b spaced apart by a plurality of pillars 7 whose ends are fixed in holes 8 in the plates 6a, 6b. A first plate 6a, furthest from the drive motor 2, has three apertures 9, 10, 1 1 in a line across a central band of the plate 6a. The outer apertures 9, 1 1 receive the rotary shafts 5 of the compressed air motors 4 with significant clearance and the central aperture 10 receives a pilot shaft 12 in a snug fit.

Each compressed air motor 4 is received in a housing 13 of a generally cylindrical configuration such that its rotary shaft 5 is eccentrically disposed relative to the housing 13 and the outer apertures 9, 1 1 of the first plate 6a. The housing and motor assemblies 4, 13 are each rotatably disposed between the plates 6a, 6b such that rotation of the assemblies 4, 13 relative to the retaining structure permits the distance between the longitudinal axes of the rotary shafts 5 to be adjusted. The clearances between the rotary shafts 5 and the respective apertures 9, 1 1 in the first plate 6a are dimensioned so as to accommodate this movement.

A second plate 6b of the retaining structure has an air inlet aperture 14 which connects the sleeve 3 to air distribution passages 15 by which air is carried from the air inlet aperture 14 to inlets of the compressed air driven motors 4.

Locking pins 16 are provided between the housings 13 and the second plate 6b to lock the housing and motor assembly 4, 13 against rotation. In addition removable locking discs 17 (shown in figure 3 only) may be secured in the outer apertures 9, 11 of the first plate 6a so as to secure the relative positioning of the rotary shafts 5 relative to the outer apertures 9, 11.

The free end of each rotary shaft 5 has an axial bore 18 designed to engageably receive a spindle 19 of a rotary machine tool 20. Three different machine tools 20a, 20b, 20c are shown, by way of example, in figure 1. The first tool 20a comprises a flat disc 21 having an abrasive end surface 22 that can be used, for example, in facing the end of a pipe. The second 20b is in the form of a cylinder in which the circumferential surface 23 is coated with abrasive material. The third is a flap wheel 24 that may be used for polishing the inside of a pipe or for removing rust, oxide, scale or burs.

The main drive motor 2 is received in the sleeve 3 and is drivingly connected to an aperture 25 in the main body 1 in such a manner that operation of the drive motor 2 causes rotation of the main body 1. The sleeve 3 has a side port to which is connected an air throttle 26 which operates to feed compressed air to the air inlet 14 of the main body 1.

In use, compressed air enters the air inlet 14 of the main body 1 which can be static (with main drive motor turned off) or rotating (main drive motor turned on). The compressed air is distributed to the housings 13 through the distribution passages 15 and is directed into the air driven motors 4 so as to drive the rotary shafts 5.

In this mode the apparatus may be used to perform various different tasks, examples of which are shown in figure 4. In each case the user selects the appropriate machine tools to insert into the rotary shafts 5 and rotates the housings 13 relative to the main body 1 so as to adjust the distance between the axes of the rotary shafts 5 to the desired amount. The machine tools 20 and the housings 13 are then locked in place using the locking pins and discs 16, 17 as described above, the pilot shaft 12 is screwed into the central aperture 10 of the first plate 6a and the apparatus is presented to the work-piece, the pilot shaft 12 being used to guide the main body into the bore of the work-piece. The pilot shaft 12 may support a stationary pilot wheel that is complementary to the bore of the workpiece.

In figure 4a the apparatus shown is diagrammatically with two grinding wheels 20 that are used to grind or polish the outer surface of a pipe 30. The spacing between the rotary shafts 5 is set such that the periphery of the two wheels 20 are in contact with the exterior surface of the pipe 30 at diametrically opposed locations. The apparatus may be hand-held or supported in an appropriate support structure and the motor and air throttle are then activated so that the main body 1 rotates and the grinding wheels 20 orbit around the pipe 30 about the pilot shaft 12 whilst rotating with the rotary shaft 5.

Figure 4b shows the apparatus fitted with two grinding wheels that are spaced apart so as to condition the inside of the pipe bore 31. In figure 4c one wheel is used to condition the bore whilst the other orbits around the exterior surface of the pipe.

In figure 4d the machine tools are tapered grinding wheels that are presented to an outer edge 32 of the pipe wall so as to machine a chamfer. In figure 4e a grinding disc is used to machine an end face 33 of the pipe wall whilst a grinding wheel orbits around the outside surface of the pipe.

In figures 4f and 4g there is shown two facing discs that are used to grind or polish the end face of the pipe and/or an annular recess inside the pipe bore.

Figure 4h shows an operation similar to that of figure 4d except that the tapered grinding wheels are used to machine a chamfer on the inside edge 34 of the bore.

In figure 4i the apparatus is shown with tools for both grinding and chamfering the inside surface of the bore.

In figure 4j the apparatus is fitted with facing discs that are used to face an exterior shoulder 35 as well as an end face of the pipe.

In figure 4k the apparatus is used to chamfer both the inside and outside edge of the pipe bore and in figure 41 the pipe is shown as being chamfered on its outside surface and ground in the bore.

Finally, in figure 4m a tapered grinding wheel is used to machine a tapered surface of a pipe which may be threaded.

The apparatus of the present invention may be fitted with a cutting wheel that can be used to undercut the internal or external surface of a pipe so as to form annular grooves in which O-rings or the like may be seated. Similarly an appropriate tool may be used to clean or re-grind an existing undercut. .An example of this is shown in figure 5 in which two grinding wheels 40 are employed cut or condition axially spaced annular grooves 41 on the exterior surface of a pipe 42.

Figure 6 shows a pipe 50 the end of which has been inserted into an aperture 51 in a wall 52 and welded to the wall 52 as indicated at reference numerals 53. Facing discs 54 are used to clean up the weld 53 so that the weld material is ground until it is flush with the plane of the wall 52.

In figure 7 there is shown an operation by which the apparatus can be used to clean up the threads of a bolt or stud 60 or the like.

In figure 8 there is shown a plurality of equi-spaced parallel pipes 70 that are supported in a steel membrane 71. The proximity of the pipes 70 is such that 7

conventional methods for conditioning the exterior surfaces of the pipes are ineffective or time-consuming in view of the restricted access. The apparatus of the present invention is shown diagrammatically as two grinding wheels 72 cleaning the outside surface of second pipe 70 from the left. The size of the grinding wheels 72 can be selected so that there is sufficient clearance for them to orbit around the pipe 70 without interfering with the adjacent pipes.

Figures 9 and 10 show the apparatus of the present invention being used in an alternative mode of operation to condition the interior and exterior wall of a large pipe 80 simultaneously. In this configuration the main body 1 is removed from the main drive motor 2 and is attached to a compressed air source 81 such that in operation the main body 1 is static relative to the air source but the rotary shafts 5 are still driven by the air motors. The rotary shafts 5 are fitted with flap wheels 82 and the central pilot shaft 12 is replaced with a roller carriage 83 that screws into the central aperture 10 of the first plate 6a. The roller carriage 83 has two pairs of support rollers 84, each pair of rollers being disposed outboard of the flap wheels 82 with the rollers of each pair being separated by a pre-determined distance equivalent to the wall thickness t of the pipe 80. The motor and housing assemblies 4, 13 are then rotated to adjust the distance between the peripheries of the wheels 82 to an amount equivalent to the wall thickness t of the pipe to be conditioned. The apparatus is presented to an end of an open pipe 80 so that the wall is received between the flap wheels 82 and the roller 84 of each pair of rollers. The apparatus may be hand-held and guided around the wall of the pipe so as to condition the inside and outside surface or, alternatively the apparatus may be attached to a support such as a rotating arm (not shown) or the like that extends from a body (not shown) disposed in the pipe bore and automatically guided around the pipe wall.

In figures 11 and 12 the apparatus is shown in a further alternative mode of operation in which it is used to condition the bore wall 90 of a pipe 91. The main body 1 is connected to the main drive motor as in the mode of operation described in relation to figures 1 to 8 so that the main body 1 is rotatable relative to the motor 2. The rotary shafts 5 are fitted with appropriate machine tools 26 such as flap wheels 8

and a roller carriage 92 is screw connected to the central aperture 10 of the first plate 6a. The roller carriage 92 in this configuration comprises a pair of rollers 93 disposed between the flap wheels 20 such that their peripheries are at the same radial distance from the centre 94 of the main body, the distance between the flap wheels 20 having been set by rotating the housing and motor 13, 4 assemblies and locking them in place as described above. In use, the apparatus is inserted into the bore of the pipe so that the rollers 93 and wheels 20 contact the bore wall 90 of the pipe 91. The motor 2 and throttle 26 are then activated so as to rotate the main body 1 and the rotary shafts 5. The wheels 20 thus orbit about the centre 93 of the pipe 91 so as to pass over the full circumference of the bore wall 90 and the wheels 20 rotate with the rotary shafts 5 so as to grind the surface of the bore. The embodiment of figure 11 shows the apparatus being used to grind an annular weld 95.

The apparatus of the present invention may be used to treat the surface of a non-cylindrical object. For example, in figure 13 the apparatus is fitted with a cutting disc 100 and is used to cut a surface 101 of a valve canopy 102. In figure 14 there is shown a grinding wheel 103 that is used to mill a bore 104 in an object 105 and in figure 15 there is shown a grinding disc 106 used to clean a valve seat 107. In the latter example the pilot shaft 12 is fitted with a pilot cylinder 108 that is slotted at 109 to accommodate the grinding disc 106, the cylinder 108 being received in a bore 1 10 of the seat 107.

Figure 16 shows an alternative embodiment of the main body 1 of the apparatus in which only one of the rotary shafts 5 is eccentrically disposed in a rotary housing 13. The other shaft 5' whilst being rotatable about its longitudinal axis by motors 4 otherwise remains fixed relative to the main body 1. The main body 1 is rotatable about an axis coaxial with the fixed shaft 5'.

Figures 17 to 19 illustrate how the above described alternative embodiment may be used. In the application shown in figure 17 the apparatus is hand-held and used to polish the internal and external surfaces of a tube 120 whilst the end face is simultaneously abraded. The main body 1 carries a spigot 121 disposed at the base of the fixed shaft 5' and this is used to support a pilot sleeve 122 designed to receive the tube 120 on which work is to be performed. The fixed shaft 5' is connected to a flap wheel 123 for polishing the inside diameter of the tube and the spigot 121 carries an abrasive ring 124 that abuts the end face of the tube 120. The moveable shaft 5 is connected to a second flap wheel 125 that polishes the outside diameter of the tube 120 through a slot 126 provided in the pilot sleeve.

In use, both the shafts 5, 5' rotate at high speed so as to rotate their respective flap wheels 123, 125. At the same time the main body 1 rotates about an axis coinciding with that of the fixed shaft 5' and the spigot 121, pilot sleeve 122 and abrasive ring 124 rotate with the main body 1 with the ring 122 serving to condition the end face of the tube 120. At the same time the moveable shaft 5, which has been moved by rotation of the housing 13 so that it contacts the outside surface of the tube 120, orbits the tube 120 at the same rate of rotation as the sleeve 122 so that the flap wheel 125 is always coincident with the slot 126 through the sleeve 122.

In the application shown in figure 18 the hand-held apparatus is again used to polish the interior and exterior of a tube 130. In this instance a pilot wheel 131 is connected to the main body 1 at the base of the fixed shaft 5' and in use is disposed inside the tube 130. The pilot wheel 131 rotates with the main body 1 as a flap wheel 132 on the other shaft 5 orbits the tube 130. A flap wheel 133 connected to the fixed shaft 5' serves to polish the inside of the tube 130.

In figure 19 the fixed shaft 5' carries a slotted pilot spigot 140 and the other shaft 5 is connected to an abrasive disc 141 that is designed to grind a weld 142 between a tube 143 and surrounding plate 144. As the main body 1 rotates the pilot spigot 140 rotates inside the tube 143 and the grinding disc 141 orbits the tube 143 in constant contact with the end face of the weld 142 and the tube 143. The disc 141 orbits at the same rate as the pilot spigot 140 so that it is always coincident with the slot 145 in the spigot 140.

The apparatus of the present invention is versatile in that it can be used to condition different surfaces of a pipe. Moreover, the same apparatus can be used for 10

different tasks, in particular two surfaces may be conditioned simultaneously by different conditioning techniques. The apparatus provides for a method that is significantly less labour intensive than conventional techniques and obviates the need to use selection of different conditioning devices.

It will be appreciated that numerous modifications to the above described design may be made without departing from the scope of the invention as defined in the appended claims. For example, the central pilot shaft may be hollow so as to receive objects such as small pipes or fixings and apertures so as to expose the received object to at least part of an appropriate machine tools that extends into the aperture. In addition the rotatable housings may conveniently be biased (by springs, magnets or the like) into a configuration in which the distance between the shafts is at its minimum. This feature enables the apparatus to be located on the workpiece easily and ensures that the machine tools are in constant contact with the workpiece with the requirement for adjustment of the rotatable housings. The shaft or shafts are simply pushed against the bias so that the distance is sufficient to receive the workpiece and then release to allow the tools to come into contact with the appropriate part of the workpiece.

Claims

1 1CLAIMS

1. Apparatus for conditioning surfaces of an object, the apparatus comprising a main body having at least two rotary members, each member having means for engaging a machining tool, and first drive means for driving the rotary members in rotation, wherein at least one olO-f the rotary members is eccentrically mounted in a rotatable housing such that the housing(s) may be rotated to alter the distance between centres of the rotary members.

2. Apparatus according to claim 1, wherein the means for engaging a machining tool releasably engages the machining tool.

3. Apparatus according to claim 1 or 2, wherein the rotary members are shafts.

4. Apparatus according to any one of claim 1,2 or 3, wherein each housing houses the first drive means.

5. Apparatus according to any preceding claim, wherein at least one of the housings is biased into a position in which the distance between the centres of the rotary members is at a minimum.

6. Apparatus according to any preceding claim, wherein the first drive means is a motor that drives a respective rotary member.

7. Apparatus according to any preceding claim, wherein a locking element is provided to lock the housings in a selected position.

8. Apparatus according to claim 7, wherein the locking element is a disc that is received in an aperture of the main body and is locked to the housing prevent rotation of the housing relative to the main body. 12

9. Apparatus according to claim 7 or 8, wherein the housing is locked to the main body by means of a locking pin.

10. Apparatus according to any preceding claim, wherein the main body is detachably connected to a second drive member that rotates the main body relative thereto.

11. Apparatus according to claim 10, wherein the second drive member is a motor.

12. Apparatus according to any preceding claim, wherein there is provided a pilot shaft that is central to the main body.

13. Apparatus according to claim 12, wherein the pilot shaft is tubular and has at least one aperture that receives part of a machining tool.

14. Apparatus according to any preceding claim, wherein the main body is provided with one or more rollers that, in use, support the head on a work-piece.

15. Apparatus according to any preceding claim, wherein the first drive means are compressed air driven motors.

16. Apparatus according to claim 15, wherein there is provided a throttle for supplying compressed air to the motors.

17. Apparatus for conditioning the surfaces of a cylinder substantially as hereinbefore described with reference to the accompanying drawings.