GB2377398A

GB2377398A - Machining apparatus

Info

Publication number: GB2377398A
Application number: GB0116747A
Authority: GB
Inventors: Malcolm Robert James
Original assignee: Rolls Royce PLC
Current assignee: Rolls Royce PLC
Priority date: 2001-07-10
Filing date: 2001-07-10
Publication date: 2003-01-15
Also published as: GB0116747D0

Abstract

Machining apparatus (10) for machining an article comprising a carrier member (20) and a cutting arrangement (22) on the carrier member (20). The cutting arrangement (22) comprises first and second cutting means (24,26). Each cutting means (24,26) is movable between a respective first condition and a respective second condition in which the first and second cutting means can machine the article. The apparatus may be used to cut a recess in the casing of a compressor for locating stator.

Description

Machining Apparatus This invention relates to machining apparatus. More particularly, but not exclusively, the invention relates to machining apparatus for use in forming opposed grooves in the sides of a recess, for example a circumferentially extending recess formed in the casing of part of a gas turbine engine.

In the intermediate compressor stage of a gas turbine engine, stator vanes are provided between adjacent arrays of compressor blades. The stator vanes are located at their radially outer edges in a circumferentially extending recess in the casing of the compressor. The side walls of the recess define opposed circumferentially extending grooves which can receive the axially extending flanges on the radially outer shrouds of the stator vanes. At present, each groove is machined individually.

According to one aspect of this invention there is provided machining apparatus for machining an article, the apparatus comprising a carrier member and a cutting arrangement on the carrier member, the cutting arrangement comprising first and second cutting means, each cutting means being movable between a respective first condition and a respective second condition, in which second condition the first and second cutting means can machine the article.

Preferably, the first and second cutting means are arranged such that they are generally opposite each other, at least in the respective second conditions. Thus, the preferred embodiment is particularly suitable for machining surfaces which are arranged in a generally opposed relationship to each other. Preferably, the cutting arrangement is arranged such that the first and second cutting means can be moved to the second condition substantially simultaneously. The cutting arrangement may comprise a support means to support the first and second

cutting means. The support means may comprise an elongate support member.

Preferably, the first condition of each cutting means is a non-cutting condition and the second condition of each cutting means is a cutting condition.

Preferably, the first and second cutting means comprise respective first and second cutting surfaces which face away from each other, at least in said respective second conditions.

In a first embodiment, the cutting arrangement may be rotatably movable to move the first and second cutting means into the respective second conditions. The cutting arrangement is conveniently substantially fixedly mounted on the carrier member, and the carrier member may be rotatably mountable on a support assembly for supporting the machining apparatus. The support assembly may include means for rotating the carrier member between said first and second conditions.

In this first embodiment, the first and second cutting means may be mounted at respective opposite end regions of the support means.

The first and second cutting means may extend beyond the carrier member at least when the cutting arrangement is moved into said second condition.

In a second embodiment, the first and second cutting means are linearly movable into the respective second conditions and may be mounted on the support means for linear movement therealong relative to the carrier member.

Preferably, the first and second cutting means are mounted on the support means such that they can move relative to each other in opposite directions. In this embodiment, the support means may comprise a linear displacement member, which may be a shaft. The first and second cutting means mounted on the displacement member. The support means may be capable of moving the first and second cutting means in said opposite directions.

The support means preferably comprises a linear displacement member which may comprise an elongate worm gear having threads co-operating with corresponding threads on the cutting means. The displacement member may extend through the first and second cutting means.

The support means may further include a support member on which the displacement member is mounted. The support member may include first and second opposite raised end portions in which respective opposite ends of the displacement member may be journalled.

The support member may include a guide region to guide movement of the first and second cutting means therealong.

The guide region may include rails extending a major proportion of the length of the support member.

According to another aspect of this invention, there is provided a method of machining an article, comprising providing machining apparatus as described above, arranging the machining apparatus in machining relationship with the article, moving the first and second cutting means to respective second conditions, and machining the article with said first and second cutting means.

Preferably, the first and second cutting means are arranged opposite each other to machine the article at generally opposed regions of the article. The first and second cutting means are preferably arranged to face away from each other.

In one embodiment, the step of moving the first and second cutting means to the respective second condition comprises rotating the first and second cutting means to the respective second condition. The support means may be substantially fixedly mounted on the carrier member to be rotated therewith. The carrier means may be mounted on a drive assembly to effect said rotation of the carrier member.

In another embodiment, the step of moving the first and second cutting means may comprise moving the first and

second cutting means linearly in opposite directions to each other. The first and second cutting means may be mounted on a displacement member, which may be an elongate worm gear. The displacement member may be rotated about its longitudinal axis to move the first and second cutting means as aforesaid.

Embodiments of the invention will now be described by way of example only, with reference to the accompanying drawings, in which Fig. 1 is a part sectional side view of one embodiment of the invention; Fig. 2 is a view along the lines II-II in Fig. 1; Fig. 3 is a side view of part of another embodiment of the invention.

Referring to Fig. 1, there is shown part of a machining apparatus 10 for machining an opposed pair of grooves 12,14 in the sides 12A, 14A of a circumferentially extending recess 16 in a compressor casing 18.

The machining apparatus 10 comprises a carrier member 20 on which is supported a cutting arrangement 22 comprising first and second cutting means 24,26 and a support member 28 supporting the first and second cutting means 24,26. The first and second cutting means 24, 26 are arranged on opposite end regions of the support member 28 and have respective cutting surfaces 30,32 which face outwardly, away from each other.

In one embodiment shown in Figs 1 and 2 the casing 18 is mounted on a rotatable part of a machining tool (not shown). The tool includes a fixed support assembly (not shown), and the carrier member 20 is mounted on the fixed support assembly. The fixed support assembly comprises rotary drive means (also not shown) to rotate the carrier member 20 about an axis X. When it is desired to machine the grooves 12,14 in the sides 12A, 14A of the recess 16 in the casing 18, the cutting arrangement 22 is inserted into the recess 16 with the support member 28 extending

generally parallel to the sides 12A, 14A. The carrier member 20 is then rotated about the axis X to the position in which the support member 28 is as shown in dashed lines in Fig. 2. At this stage the casing 18 is rotated about its axis, in the direction indicated by the arrow Y, and the carrier member 20 is then progressively further rotated to cut into the sides 12A, 14A of the recess 16 until the support member 28 reaches the position shown in solid lines in Fig. 2, thereby cutting the grooves 12,14.

Alternatively, the rotation of the casing 18 can commence prior to or while the cutting arrangement is inserted into the recess 16. Rotation of the casing 18 is continued while the support member 28 is rotated about the axis X to cut the grooves 12,14.

A further embodiment is shown in Fig. 3, which is in the form of machining apparatus 110 comprising a carrier member 120 and a cutting arrangement 122 supported on the carrier member 120.

The cutting arrangement 122 comprises first and second cutting means 124,126 and support means 128 on which the first and second cutting means 124,126 are arranged.

Each of the first and second cutting means 124,126 comprises a cutting head 130 having a cutting surface 132, which extends around the cutting head 130 sufficiently to initially cut into the sides 12A, 14A of the recess 16 of the casing 18, and then to cut along the sides 12A, 14A circumferentially of the casing to form the grooves 12,14.

Each of the first and second cutting means 124,126 also includes a main body 134 on which the cutting head is provided.

The support means 128 comprises a support member 136 mounted on the carrier member 120. The support member 136 includes first and second opposite raised end portions 138,140.

The support means 128 further includes an elongate linear drive member in the form of an elongate worm gear

142 to drive the first and second cutting means 124,126 in opposite directions. The worm gear 142 has opposite end regions which are journalled in the respective raised end portions 138,140 of the support member 136.

The elongate worm gear 142 extends through the main bodies 134 of each of the first and second cutting means 124,126. The worm gear 142 includes external threads which co-operate with internal threads on the main bodies 134.

Thus, by rotation of the worm gear 142 about its main axis in either direction as indicated by the double headed arrow A, the first and second cutting means can be moved between their non-cutting first positions, as shown in solid lines in Fig. 3 in which the cutting means 124,126 abut each other, and their cutting second positions, as shown in dashed lines in which the cutting means 124,126 are spaced from each other.

Appropriate connection means (not shown) connects at least one of the end regions of the worm gear 142 to a drive assembly (not shown) on which the machining apparatus 110 is mounted. Operation of the drive assembly and the connection means, causes the rotation of the worm gear 142 to move the cutting means 124,126 away from each other or towards each other, as desired.

In operation, the first and second cutting means 124,126 are inserted into the recess 16 in the casing 18 in which the grooves are to be cut, with the respective cutting surfaces 132 facing the sides 12A, 14A of the recess 16. The drive assembly can then rotate the worm gear 142 causing the cutting means to move outwardly relative to each other to engage the sides 12A, 14A of the recess 16 and commence the cutting into the sides 12A, 12B to begin the formation of the grooves 12,14. When this has been done, the casing 18 can then be rotated such that there is relative circumferential movement of the machining apparatus 110 around the recess 16 to cut the grooves 12,14 circumferentially of the casing 18 along the recess 16.

Various modifications can be made without departing from the scope of the invention, for example in the second embodiment shown in Fig. 3, the worm gear 142 could be replaced by another means capable of effecting linear motion of the cutting means, such as hydraulically operated means.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

CLAIMS :- 1. Machining apparatus for machining an article, the apparatus comprising a carrier member and a cutting arrangement on the carrier member, the cutting arrangement comprising first and second cutting means, each cutting means being movable between a respective first condition and a respective second condition, in which second condition each of the first and second cutting means can machine the article.
2. Machining apparatus according to Claim 1, wherein the first and second cutting means are arranged such that they are generally opposite each other, at least in the respective second conditions, and the first and second cutting means comprising respective first and second cutting surfaces which face away from each other, at least in the respective second conditions.
3. Machining apparatus according to Claim 1 or 2, wherein the cutting arrangement comprises a support means to support the first and second cutting means.
4. Machining apparatus according to Claim 3, wherein the support means comprises an elongate support member.
5. Machining apparatus according to Claim 3 or 4, wherein the cutting arrangement is substantially fixedly mounted on the carrier member, and the cutting arrangement and the carrier member are rotatably mountable on a support assembly for supporting the machining apparatus and rotating the carrier member between said first and second conditions.
6. Machining apparatus according to Claim 5, wherein the first and second cutting means are mounted at respective opposite end regions of the support means.
7. Machining apparatus according to any preceding claim wherein the first and second cutting means are rotatably movable into the respective second conditions.

<Desc/Clms Page number 9>
8. Machining apparatus according to Claim 3 or 4, wherein the first and second cutting means are mounted on the support means for linear movement therealong relative to the carrier member.
9. Machining apparatus according to Claim 8, wherein the first and second cutting means are mounted on the support means such that they can move relative to each other in opposite directions.
10. Machining apparatus according to claim 9 wherein the support means comprises a linear displacement member upon which the first and second cutting means are mounted, and the support means being capable of moving the first and second cutting means in said opposite directions.
11. Machining apparatus according to Claims 9 or 10, wherein the linear displacement member comprises an elongate worm gear having threads co-operating with corresponding threads on the cutting means, the displacement member extending through the first and second cutting means.
12. Machining apparatus according to Claims 9,10 or 11, wherein the support means further includes a support member on which the displacement member is mounted, the support member including first and second opposite raised end portions in which respective opposite ends of the displacement member are journalled.
13. Machining apparatus according to Claim 12, wherein the support member includes a guide region to guide movement of the first and second cutting means therealong, the guide region including rails extending a major proportion of the length of the support member.
14. Machining apparatus according to any of Claims 1 to 4 and 8 to 13 wherein the first and second cutting means are linearly movable into the respective second conditions.
15. A method of machining an article, comprising providing machining apparatus having first and second cutting means, arranging the machining apparatus in machining relationship

<Desc/Clms Page number 10>

with the article, moving the first and second cutting means to respective cutting conditions, and machining the article with said first and second cutting means.
16. A method according to Claim 15, wherein when the first and second cutting means are in the cutting condition, they are arranged opposite, and facing away from, each other to machine the article at generally opposed regions of the article.
17. A method according to Claim 15 or 16, wherein the step of moving the first and second cutting means to the respective cutting condition comprises rotating the first and second cutting means to the respective cutting condition.
18. A method according to Claim 17, wherein the support means is substantially fixedly mounted on the carrier member to be rotated therewith.
19. A method according to Claim 15 or 16, wherein the step of moving the first and second cutting means comprise moving the first and second cutting means linearly in opposite directions to each other.
20. A method according to Claim 19, wherein the first and second cutting means are mounted on an elongate displacement member, and the step of moving the first and second cutting means linearly includes rotating the displacement member about its longitudinal axis.
21. A method according to Claim 20, wherein the displacement member is threaded along its length and the first and second cutting means comprise internal threads whereby the aforesaid rotation of the displacement member causes the respective threads to cooperate and effect said linear movement of the first and second cutting means.
22. Machining apparatus substantially as herein described with reference to Figs. 1 and 2 of the accompanying drawings.
23. Machining apparatus substantially as herein described with reference to Fig. 3 of the accompanying drawings.

<Desc/Clms Page number 11>
24. A method of machining an article substantially as herein described with reference to Figs. 1 and 2 of the accompanying drawings.
25. A method of machining an article substantially as herein described with reference to Fig. 3 of the accompanying drawings.
26. Any novel subject matter or combination including novel subject matter disclosed herein, whether or not within the scope of or relating to the same invention as any of the preceding claims.