GB2266255A

GB2266255A - Grinding device

Info

Publication number: GB2266255A
Application number: GB9308096A
Authority: GB
Inventors: Ian George Hamilton
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-04-25
Filing date: 1993-04-20
Publication date: 1993-10-27
Anticipated expiration: 2013-04-20
Also published as: GB9209006D0; GB2266255B; GB9308096D0

Abstract

Apparatus for the grinding out of flawed interior surfaces of elongate tubes, pipes and the like, which flaws are inaccessible to normal grinding tools, comprises a grinding head (16) mounted for movement within a tube (2), on a support arrangement including an elongate rod or boom and control means for operating the grinding head (16) for rotary motion. When the apparatus is inserted in the tube (2) the grinding head is moved radially within the pipe into contact with the surface to be corrected, by means of a radial movement control device (18) including an inclined surface (32) against which a projection (28) reacts to push the support means for the head (16) radially of the tube centre-line so that the head (16) contacts the internal surface of the tube (2). <IMAGE>

Description

GRINDING DEVICE The invention is concerned with grinding devices, particularly for use in confined and/or difficultly accessible locations, such as interiors of pipes and tubes.

In the manufacture of industrial pipes and tubes, pipes many metres in length are produced which require to be an acceptable quality without flaws either on the exterior or interior surfaces. It is common to find flaws in the interior surface of such pipe which must be checked and, if feasible to do so, the inside of the pipe must be re-surfaced by a grinding technique. Difficulty is encountered in dealing with surface flaws in the interior of pipes which may be, say, fifteen metres long and perhaps only 10 cm in internal diameter. As a result, it often occurs that a large proportion of pipes are discarded from the production output, with resulting financial loss and wastage.

The invention sets out to provide a device the use of which will reduce the numbers of pipes thus wasted.

The invention provides a grinding device comprising a support means for an article having an elongate passage therein, a grinding head adapted to enter said passage and to operate upon an interior surface portion thereof, said grinding head being mounted for movement with respect to said passage upon a support arrangement including control mechanism for operation of the grinding device including the grinding head, said grinding head being arranged for rotary motion on a rotatable shaft about a central axis thereof, there being provided means for imparting to said grinding head a movement radially of said axis to control its contact with the passage interior surface, wherein said shaft is axially aligned with a non-rotatable mounting member, said means comprising an inclined guide surface arranged to exert radial force upon the non-rotatable member resulting in movement of the shaft and the grinding head into controlled contact with the passage interior surface.

Preferably, the grinding device may comprise an outer casing arranged to allow sliding contact with the passage interior surface, said contact permitting relative longitudinal movement therebetween and also limited angular adjusting movement as required. The support arrangement for the grinding head may comprise an elongate member axially received within said casing and arranged to partake of a movement including a radial component, said movement taking place relative to the outer casing and controlled by contact between a first inclined surface and a second surface in contact therewith.In examples to be described, the inclined surface may be provided on a ramp or wedge-shaped member, the projection being provided internally of the casing, or the inclined surface may be provided as a portion of a helical or part-helical guide slot arrangement provided in said casing and engaged by a projection means on said elongate member.

Conveniently, the internal projection may be a bar or roller adapted to bear against an inclined surface of the slot or wedge-shaped member at a suitable selected position.

Advantageously, the non-rotatable mounting member may be spring-biassed into an axially centralised position within the passage.

Advantageously, the grinding head may be moved axially with respect to the passage to be entered, by means of a heavy-duty elongate rod member. Adjustment heightwise of the grinding head with respect to the passage opening in order to accommodate differing passage dimensions and positional tolerances may be made along the length of the rod member. However, it may be preferably to provide for heightwise adjustment of a portion of the rod only, i.e.

at an end portion of the rod adjacent the article including said passage. Conveniently the rod member may be hinged about a horizontal axis for this purpose.

There will now be described a device according to the invention. It will be understood that the description which is to be read with reference to the drawings, is given by way of example only and not by way of limitation.

In the drawings: Figure 1 shows a schematic layout of a device according to the invention in use in the grinding out of a steel pipe, Figure lb being a continuation of Figure la; Figure 2 is a side view, partly in section, of a grinding head and a control device therefor, Figure 2b being a continuation of Figure la; Figure 3 is a sectional view of the expansion device to an enlarged scale, Figure 3b being a continuation of Figure 3a; Figure 4 is a cross-section on line IV-IV of Figure 3a; Figure 5 is a diagrammatic illustration of the operating pattern of the grinding head.

Figure 6 is an end view of an alternative control console layout in the direction of view of an operator; Figure 7 is a side view of the layout shown through the control means of Figure 6; Figure 8 is a plan view of a layout of Figures 6 and 7; and Figure 9 is a side view, partly in section, of an alternative control device for the grinding head.

Figure 1 illustrates the device according to the invention in use in a grinding operation to remove from the interior passageway of a steel pipe 2 surface flaws, de-laminations, or restrictions in the pipe diameter not yielding to the operation of a tool such as a drift or the like. The pipe 2 is supported on powered rollers 4 of support members 6. A support trolley 8 is provided which may be positionally adjusted to take account of various pipe lengths. The trolley also serves to support an elongate box-section boom 9 at the opposite end of which is a grinding head 16 adapted'to enter the pipe 2 as explained below. The boom 9 is operated from a control trolley 10 mounted for movement along a gantry 12 under the guidance of an operator 14. Intermediate boom support cradles 11 (two shown) are provided to eliminate any tendency for sagging.At the position to the right of the right-hand cradle 11 as viewed in Figure la, the boom is provided with a hinge 13 operated about a horizontal axis by means of a jacking device (not shown) and allowing vertical adjustment of the boom end portion, and the grinding head to accommodate variations in the positioning of a pipe 2 to be operated upon. This is especially advantageous when operating on long pipes and therefore handling a long boom. The operator can thus control all aspects of operation of the grinding head 16 shown in Figure 1 as being extended into the interior of the pipe 2. Positioned close behind the grinding head 16 is a radial movement control device 18, to be described below.

Figure 2 illustrates the position of the grinding head 16 within the pipe 2 mounted upon a shaft 20 and rotated by a motor 22. Secured to the rear of the motor 22 is a square section tube 24 comprising a non-rotatable elongate mounting member received within a casing 26 of the device 18. The casing 26 is provided with two sets of three spaced-apart ball bearings 27 which allow the device 18 to travel along the pipe interior as required. Any overall height adjustment is made at the control trolley.

The radial movement control device 18 comprises a roller 28 mounted in the casing 26 and a wedge-shaped member 30 having an inclined surface 32. The wedge member is secured to the end portion of a thin metal strip 34 which extends from the control trolley 10. When the operator causes the strip 34 to be pulled to the left as viewed in the Figure, the inclined surface 32 of the member 30 contacts the roller 28 and continued leftward movement (arrow X) brings an increased depth of the wedge member beneath the roller. This causes the square section tube 24 to be forced downwardly (arrow Y and see also Figure 4) against the influence of springs 36 in the manner of a radial-expansion device. Downward movement of the tube 24 causes similar movement of the grinding head 16 which comes into operating contact (at 16') with the interior surface of the pipe 2.The firmness of the contact and therefore the depth of the grinding cut can thus be controlled by movement of the wedge member 30.

Upon release of the member, the springs 36 will return the arrangement to a central axial position.

An alternative layout for the control trolley and boom supporting apparatus is illustrated in Figures 6 to 8. In this arrangement the path of the boom 9 is off-set with respect to the console 10' which is arranged to bridge the gantry 12'. Thus the operator may move the control trolley 10' along-side the path of the boom, conveniently by means of a motor on the console trolley, for inspection purposes without interfering in any way with the operation of the device. In this arrangement a trough 42 supported on a track 44 is provided, which is arranged to serve as a mounting for the boom 9. The trough is approximately semi-circular in cross-section on a radius compatible with the average inside dimensions of a pipe 2 to be operated upon, and its extreme end may be run up to the pipe 2 and clamped thereto.

The operator may also, according to operating conditions, cause the grinding head and the radial movement control device to be rotated through a small angle as shown in Figure 6 in which a control handle 38 may be moved in a rocking motion to achieve the required response. Also controlled from a control device 39 on the control trolley 10 is the operation of the grinding motor 22 and the progress of the grinding head through the pipe, i.e. the extent of its penetration of the interior thereof. In addition, a small video camera may be located adjacent to the grinding head 16, conveniently to the left of the motor 22 either above the centre line at C1, or preferably below it at C2 (Figure 2b).

In addition, the operator may initiate rotation of the power rollers 4 to rotate the pipe 2 at a slow rate as the grinding head operates, to cause one or more selected belts or zones of the pipe to be treated. In other, more severe, circumstances where the entire pipe interior requires to be ground out, the pipe 2 may be rotated as the grinding head is gradually advanced along the length of the pipe. In this way, the entire interior surface may be treated.

Figure 9 shows an alternative arrangement of radial movement control device 18' for heightwise adjustment of the level at which the grinding head 16 enters the pipe 2 to be operated upon. The boom 9 passes through a casing 48 in which are provided, in the present example, two inclined slots 50. Two transverse rods 52 are welded securely to the upper surface of the boom 9 and opposite end portions of the rods 52 are received in the slots as shown in the Figure. The strip 34' is secured to the casing 48 and when the strip is pulled by the operator, the casing 48 moves to the left relative to the boom.

Thus the rods 52 are forced to move relatively to the slots and take up positions rightwardly and downward of that shown so that the boom 9 is also forced downwardly, i.e. radially, of the casing 48 (arrow Y').

A typical grinding operation will now be described.

The pipe 2 is positioned upon the rollers 4 and the grinding head 16 is advanced from the right-hand support trolley 8 and, with any necessary heightwise adjustment made, enters the interior of the pipe by a distance appropriate to the location of the flaw in the interior surface, the pipe having been rotationally positioned so that the flaw is at the lowest point of the internal circumference. The radial movement control device, 18 or 18', wedge member 30 will then be moved to bring the tube 24 downwardly and thus to move the head 16 into contact with the flawed area to be ground out.

Visual checks may be carried out at any stage by operating the camera within the pipe, the operator reviewing on a VDU screen 40 the progress of the operation during a pause.

Should it be apparent that the angle through which the grinding operation is effective is not sufficient to deal with the problem, i.e. the width of the flaw is greater than the distance + shown in Figure 5, then the operator may impart a rocking action to the grinding head as explained above to cause the grinding head to contact an adjacent area of the pipe interior. In this way, it is possible, without the necessity repeatedly to set up the pipe on its support members, to grind a comparatively wide strip-like area (for example up to 90 ) of the interior surface to any desired lengthwise distance.

Various modifications may be made within the scope of the invention as defined by the following claims.

Claims

1. A grinding device comprising a support means for an article having an elongate passage therein, a grinding head adapted to enter said passage and to operate upon an interior surface portion thereof, said grinding head being mounted for movement with respect to said passage upon a support arrangement including control mechanism for operation of the grinding device including the grinding head, said grinding head being arranged for rotary motion on a rotatable shaft about a central axis thereof, there being provided means for imparting to said grinding head a movement radially of said axis to control its contact with the passage interior surface, wherein said shaft is axially aligned with a non-rotatable mounting member, said means comprising an inclined guide surface arranged to exert radial force upon the non-rotatable member resulting in movement of the shaft and the grinding head into controlled contact with the passage interior surface.

2. A device as claimed in claim 1, wherein there is provided an outer casing arranged to allow sliding contact with the passage interior surface, said contact permitting relative longitudinal movement therebetween.

3. A device as claimed in claim 2, wherein the relative sliding contact between said casing and the passage interior surface further permits of limited angular adjusting movement of said casing about a lengthwise axis.

4. A device as claimed in any one of the preceding claims, wherein the support arrangement for the grinding head comprises an elongate member axially received within said casing and arranged to partake of a movement including a radial component, said movement taking place relative to the outer casing and controlled by contact between a first inclined surface and a second surface in contact therewith.

5. A device as claimed in claim 4, wherein said inclined surface is provided on a ramp or wedge-shaped member.

6. A device as claimed in claim 4, wherein said inclined surface is provided as a portion of a guide slot arrangement.

7. A device as claimed in claim 6, wherein the slot arrangement includes at least one helical or part-helical slot.

8. A device as claimed in claim 7, wherein the or each slot is engaged by projection means on said elongate member.

9. A device as claimed in any one of the preceding claims, wherein the non-rotatable member is provided with spring-biassing means adapted to bias the member into an axially centralised position within the passage.

10. A device as claimed in any one of the preceding claims, wherein the grinding head is moved axially with respect to the passage by means of a heavy-duty rod member having a hinge means provided at a location therealong, permitting heightwise adjustment of a portion thereof between said hinge means and the grinding head.

11. A grinding device adapted for use to operate upon an interior surface portion of an article having an elongate passage therein, constructed, arranged and adapted to operate substantially as hereinbefore described with reference to and as shown in the drawings.