Tooling for holding thin metal parts making up a hollow structure in order to enable them to be friction-welded together

Abstract

The invention relates to tooling for holding parts in position to enable them to be friction welded together in order to construct a hollow structure, the tooling comprises: a framework made up of two frames for receiving the parts for welding together in their positions for forming the hollow structure, the parts comprising preformed parts and an intermediate section; shape-holder members for holding the hollow structure, associating backing thrust members and lateral grip members for gripping the outsides of the preformed parts; anvils suitable for being placed inside the set of preformed parts beside the section; and clamping means operable to take up a clamping position in which they cause opposing thrust to be applied against the anvil and the inside face of a preformed part, its part itself bears against the shape-holder members.

Claims

1. A tooling for holding a set of preformed parts to be friction-welded together to construct a generally plane hollow structure being made up of the set of preformed parts the tooling comprising: a framework to receive the preformed parts inside the framework for welding together to form the hollow structure, the framework being subdivided into two frames to be joined together in an assembled position on both outer surfaces of the preformed parts and extending in the general plane in which the hollow structure extends, the framework including shape-holder members which are shaped to correspond and contact the outer surfaces of the preformed parts; at least one anvil disposed inside the framework; and a reversible clamp arranged as deformable members and installed inside the framework and movable between a clamping position and an assembly position in which the deformable members are able to be inserted inside the set of preformed parts, and wherein in the clamping position the deformable members cause opposing thrust to be applied between the anvil and the inside surface of at least one preformed part disposed inside the framework.

2. The tooling according to claim 1, wherein the shape-holder members comprise at least one lateral grip member for gripping an outer preformed part of the hollow structure.

3. The tooling according to claim 2, wherein the lateral grip member is mounted on the framework to move between a disengaged position in which grip on the preformed parts associated is interrupted, and a clamping position in which grip is exerted on the outer surface of the preformed part.

4. The tooling according to claim 2, wherein the lateral grip member includes a jaw of shape that is complementary to the preformed part.

5. The tooling according to claim 2, wherein the lateral grip member is subdivided into a plurality of individual lateral grip members that are distributed along the framework along and extend in the extension direction of the hollow structure that is to be obtained.

6. The tooling according to claim 5, wherein the individual lateral grip members are individually mounted to move on the framework.

7. The tooling according to claim 1, wherein the shape-holder members comprise backing thrust members that are individually mounted on one and/or the other of the frames via position-adjustment means.

8. The tooling according to claim 7, wherein the backing thrust members are distributed at least along a pair of length members forming part of each of the frames, wherein a path for passing a welding tool is formed between the length members.

9. A method of implementing holder tooling according to claim 1, wherein the method consists in performing the following operations: placing a stiffener section in position on one of the frames; placing the anvil in position on the frame beside the stiffener section on the side allocated thereto; placing the reversible clamp associated with the anvil on the frame on a corresponding lateral side of the frame; docking the parts for welding in succession against the section by sliding corresponding walls of the parts under at least one of the anvil and or the reversible clamp and over at least one of the shape-holder members; putting the other frame in place and joining the frame together; and operating the reversible clamp.

10. The method according to claim 9, wherein the shape-holder members comprise at least one lateral grip member for gripping an outer preformed part of the hollow structure, wherein the method includes the operation consisting in operating the lateral grip member prior to operating the reversible clamp.

11. The method according to claim 9, wherein the method comprises, after the parts have been welded together along one of the outer surfaces of the hollow structure that is to be obtained, turning the framework over in order to weld the parts together along the other outer surface of the hollow structure that is to be obtained.

12. The method according to claim 9, wherein operating the reversible clamp comprises applying lateral thrust against the anvil, to cause flanges of the section to bear against the corresponding edges of the preformed parts.

13. A method of forming a generally hollow structure formed a set of preformed parts with tooling, the method comprising: providing a tooling framework having two frames to receive the set of preformed parts inside the framework; placing a stiffener section in position on one of the two frames; placing at least one anvil inside the framework on the one frame beside the stiffener section; installing a reversible clamp inside the framework and inside the set of preformed parts; bringing the set of preformed parts successively into abutment against the stiffener section to a welding position, wherein the at least one anvil and the reversible clamp are disposed inside the preformed parts in the welding position; moving the two frames to an assembled position and joining the two frames together; and operating the reversible clamp to move to a clamping position to cause opposing thrust to be applied between the anvil and an inside surface of at least one of the set of preformed parts.

14. A method of forming a generally hollow structure with of a set of preformed parts and with tooling for holding the preformed parts, the method comprising: providing a tooling framework having two frames being movable with respect to each other to receive the set of preformed parts inside the framework; placing at least one anvil inside the framework; installing a reversible clamp inside the framework and inside the set of preformed parts; bringing the set of preformed parts together in a welding position to define the generally hollow structure, wherein the at least one anvil and the reversible clamp are disposed inside the preformed parts in the welding position; moving the two frames to an assembled position and joining the two frames together; and operating the reversible clamp to move to a clamping position to apply thrust in at least two directions such that thrust is applied in a lateral direction to the anvil and in a second direction to an inside surface of at least one of the set of preformed parts.

15. The method of claim 14, further comprising: placing a stiffener section in position on one of the two frames; and bringing the preformed parts together to abut against the stiffener section; placing the anvil inside the framework adjacent the stiffener section; and operating the reversible clamp to move to the clamping position to apply thrust in at least two directions to the anvil and to the inside surface of at least one of the set of preformed parts.

16. The method according to claim 15, wherein the stiffener section has a flange disposed at an end, wherein at least one of the set of preformed parts overlaps the flange, wherein operating the reversible clamp comprises applying lateral thrust against the anvil to cause the flanges of the section to bear against the corresponding edges of the preformed parts.

17. The method of claim 14, further comprising operating shape-holder members to grip along an outer surface of the set of preformed parts prior to operating the reversible clamp.

18. The method according to claim 14, further comprising turning the framework over after the set of parts have been welded together along a first face in order to weld the parts together along a second face.

19. The method according to claim 14, wherein the reversible clamp comprises a deformable member, wherein operating the reversible clamp comprises moving the deformable member to a clamping position to apply the thrust in at least two directions.

20. The method according to claim 19, wherein the deformable member comprises an inflatable bladder, wherein operating the reversible clamp comprises inflating the bladder to apply the thrust in at least two directions.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) A preferred embodiment of the present invention is described below with reference to the figures of the accompanying sheets, in which:

(2) FIG. 1 is an example of a hollow structure that is to be obtained by joining together the various parts making it up by friction-welding;

(3) FIG. 2 is a detail of FIG. 1, showing the particular ways in which an edge of one part for welding is arranged to overlap an edge of another part;

(4) FIGS. 3 and 4 are respectively exploded and assembled perspective views of tooling for holding parts for welding together in order to obtain a hollow structure as shown in FIG. 1; and

(5) FIG. 5 is a section view of the holding tooling of FIGS. 3 and 4 having installed therein the various parts for welding together.

DETAILED DESCRIPTION

(6) In FIG. 1, a hollow structure 1 is obtained from a plurality of parts 2, 3, 4 that are welded to one another by friction. In the embodiment shown, the hollow structure 1 is an airfoil that presents a leading profile and a trailing profile 6, and that includes an internal stiffening section 4. This hollow structure 1 has an overall height of about 70 mm for a width of about 500 mm and a length in its general extension plane of about 3000 mm. Two parts 2 and 3 are preshaped respectively to form the leading profile 5 and the trailing profile 6, and they are assembled together via the section 4. With reference also to FIG. 2, the section 4 is an I-shaped member made up of a web 7 provided at each of its ends with a flange 8, 9 that is used for welding the section 4 to the corresponding edges of the preformed parts 2, 3. Each of the flanges 8, 9 of the section 4 has rabbets i0, ii for receiving in overlap the corresponding edges of the preformed parts 2, 3 using the “self-holding joint” assembly technique. The preformed parts 2, 3 and the section 4 are assembled together by a weld bead using the friction-welding technique whereby a welding pin heats the parts 2 and 4 and then the parts 3 and 4 for assembling together in succession so as to cause material forming the weld bead to spread and mix.

(7) In FIGS. 3 to 5, tooling is organized for holding the parts 2, 3, 4 making up the hollow structure 1 shown in FIG. 1 for the purpose of performing all of the welding operations needed to obtain the hollow structure 1. The tooling is arranged to enable all of these welding operations to be performed starting from a single installation of the parts 2, 3, 4 making up the hollow structure 1 on the tooling. This installation can be performed quickly and easily, with the parts 2, 3, 4 being accurately positioned relative to one another, while nevertheless taking account of docking tolerances between the parts 2, 3, 4 and any possible variations in their thicknesses. In addition, the tooling serves to hold the hollow structure 1 in shape in spite of the forces and tensions to which it is subjected during the various welding operations, as results in particular from pressing the welding pin against the parts 2, 3, 4 and from the heat given off by forming the weld beads.

(8) The tooling comprises two frames 12, 13 that make up a framework 31 for receiving the parts 2, 3, 4 for welding together in their positions for forming the hollow structure 1. These frames 12, 13 are generally rectangular, each having middle length-members 14, 15 extending in the general extension direction of the hollow structure 1 to be obtained. For each of the pairs of length members 14, 15, a path 16 is provided for passing the welding pin between the length members 14, 15 so as to enable the pin to be pressed against the edges of the parts 2, 3, 4 for welding together. The frames 12, 13 are suitable for being placed on either side of the hollow structure 1 that is to be obtained, on either side of its general extension plane, and they are provided with junction means 17, 18 for joining them together, which means are constituted by co-operating fastener members, for example.

(9) A pair of anvils 19, 20 is fitted inside the preformed parts 2, 3 placed in their welding positions on the framework 31. This pair of anvils 19, 20 may be constituted by anvils that are structurally distinct or by a one-piece unit, in which case the anvils 19, 20 are connected together at their ends in a zone lying outside the zone in which the weld beads are formed. More particularly in FIG. 5, the anvils 19, 20 are placed on either side of the web 7 of the section 4 in order to exert lateral thrust thereagainst so as to hold it in position. This lateral thrust is applied by using clamping means 21, 22 located respectively on opposite sides of the anvils 19, 20 on their sides remote from the sides that thrust against the web 7 of the section 4. These clamping means 21, 22 comprise a body 23 that houses an inflatable bladder 24. Each frame 12, 13 carries backing thrust members 25, 26 against which the preformed parts 2, 3 press when the clamping means 21, 22 are put into operation. These backing thrust members 25, 26 are members that comprise a set of members for holding the hollow structure that is to be obtained in shape. Inflating the bladders 24 causes them to be pressed against the corresponding anvils 19, 20 and causes an opposing thrust to be applied by the bodies 23 against the inside faces of the preformed parts 2, 3 with which they are associated. The preformed parts 2, 3 are clamped between the clamping means 21, 22 and more particularly between the body 23 and the backing thrust members 25, 26 that are carried by the frames 12, 13. The backing thrust members 25, 26 are carried in particular by the middle length members 14, 15 forming parts of the frames 12, 13, being positioned to correspond with the bearing zones occupied by the body 23 of each of the clamping means 21, 22 against the inside faces of the corresponding preformed parts 2, 3.

(10) The framework 31 is provided with lateral grip members 27 for gripping the preformed parts 2, 3, which members are disposed along the framework 31 along its side corresponding to the general extension of the hollow structure 1 that is to be obtained. These lateral grip members 27 are members forming part of the set of members for holding the hollow structure i that is to be obtained in shape. These lateral grip members 27 are constituted by a plurality of individual lateral grip members that are mounted on the framework 31 via individual movement means 28. The lateral grip members 27 are movable between a disengaged position enabling the preformed parts 2, 3 to be installed on the framework 31, and a clamping position in which the lateral grip members 27 engage the ends of the preformed parts 2, 3. Each lateral grip member 27 has a jaw 29 of shape that is complementary to the portion of the preformed parts 2, 3 with which it comes into engagement. While the welding operations are being performed, the preformed parts 2, 3 are held in shape on the framework 31 by the combination of thrust exerted against them by the shape-holder members, comprising the backing thrust members 25, 26 and the lateral grip members 27.

(11) In FIG. 4, the framework 31 is fitted with handle members 30 enabling it to be turned over. These handle members 30 serve, after welding operations have been preformed on one of the faces of the hollow structure 1 that is to be obtained, to turn the framework 31 over and allow welding operations to be performed on the other face of the hollow structure 1. Turning the structure over in this way serves more particularly to enable all of the operations of welding the parts 2, 3, 4 together to be preformed so as to obtain the hollow structure 1 without it being necessary to remove the parts 2, 3, 4 from the holder tooling.