BLIND RIVET, AS WELL AS SYSTEM AND METHOD FOR PRODUCING SEALED BLIND RIVET JOINTS

Description

Technical field

[0001] The present description relates to a blind rivet and a system and method for producing sealed blind rivet joints. Technical background

[0002] In aircraft construction, numerous riveted joints are typically used to assemble individual aircraft components. Conventional riveted joints are designed in two parts and consist of a rivet and a rivet nut. Creating the riveted joints requires a rivet hole and access to the rivet hole from both sides in order to insert the rivet into the rivet hole from one side and thread the rivet nut onto the rivet on the other side. This is time-consuming and, depending on the design of the workpiece, can be difficult or cumbersome. For larger workpieces that are riveted together at more than just the edges, two people are required to attach the rivet and rivet nut.

[0003] A simplified variant for producing riveted joints uses blind rivets, which only require one-sided access to a rivet hole and can also be automated using appropriate tools (see US 2014 / 0044498 A1). In addition to a significant reduction in installation time, costs, and noise, the reduced accessibility requirements enable new, different designs. Ergonomics are improved, and only a single person is required to produce a riveted joint.

[0004] Particularly when connecting aircraft components that come into direct contact with the environment, blind rivet joints may have gaps, recesses, or crevices that need to be sealed to ensure a seamless and smooth application of a paint layer. Suitable post-treatment typically involves applying a sealant to the rivet joints, filling, and then removing excess sealant. However, this can be time-consuming and at least partially offset the time and cost savings associated with blind rivet installation. Description

[0005] It is therefore an object of the invention to propose a blind rivet, a connection system and / or a method for producing a blind rivet connection in which the manual effort during post-treatment can be reduced.

[0006] This object is achieved by a blind rivet having the features of independent claim 1. Advantageous embodiments and further developments of the invention can be found in the subclaims and the following description.

[0007] A blind rivet for connecting workpieces is proposed, comprising a hollow, deformable rivet body with a support collar and a sleeve adjoining thereto, a rivet mandrel arranged in the sleeve and extending through the support collar with a tool receiving head, and at least one sealing ring, wherein the at least one sealing ring is arranged between the support collar and the tool receiving head, wherein the at least one sealing ring consists of a curable and not fully cured sealing material, wherein the at least one sealing ring is arranged such that it is pressed axially towards the support collar upon contraction of the blind rivet by a tool connectable to the tool receiving head or by a section of the rivet mandrel, and wherein the at least one sealing ring is designed toWhen the sealing ring is pressed, it flows radially and axially into gaps and spaces on the support collar and between the support collar and the workpieces and adheres there.

[0008] The invention proposes an alternative blind rivet which, upon tool-guided contraction, automatically leads to the complete sealing of the blind rivet connection to the workpieces. Conventional tools that are also used in standard riveting processes can be used to fasten the blind rivet. The previously explained advantages of the blind rivet connection over a conventional rivet connection can be maintained, while at the same time the effort required for rework, particularly grinding, is significantly reduced by automatically filling gaps and spaces. The essential components of the blind rivet required for this purpose are described below.

[0009] The rivet body essentially consists of the sleeve, which is inserted into a rivet hole in the workpieces to be joined. The insertion depth is limited by the support collar, which rests on an edge surface surrounding the rivet hole. The sleeve is designed in such a way that it is deformed by a tensile force that pulls an end of the sleeve facing away from the rivet hole towards the rivet hole. The sleeve is shortened in the axial direction and widens in the radial direction, so that it is squeezed against the workpieces on the side facing away from the support collar. The workpieces are then clamped between the support collar and the deformed part of the sleeve.

[0010] The rivet mandrel is designed to pull the rivet body toward the rivet hole as described. This can be achieved in different ways. In a first variant, the rivet mandrel could simply have a tensile connection with the end of the rivet body facing away from the support collar and be pulled by the tool attached to the rivet mandrel. In a second variant, the sleeve could have an internal thread and the rivet mandrel a complementary external thread. Driven by the tool, the rivet mandrel can be rotated so that the interlocking threads exert a tensile force on the relevant end of the rivet body, leading to the desired deformation of the sleeve.

[0011] The tool holder head is designed to create a connection between the rivet mandrel and the tool. The tool holder head can create a torsion-resistant or tensile bond, depending on the design of the rivet mandrel.

[0012] The components described above are common in conventional blind rivets. However, an essential element of the blind rivet according to the invention is the at least one sealing ring arranged between the support collar and the tool holder head. The sealing ring can be removed from a container and placed on the blind rivet before installation. Alternatively, the sealing ring is already arranged on the blind rivet before installation. It should be noted that the position specification is to be understood in such a way that the sealing ring could be arranged in a general form at any desired location between the tool holder head and the support collar, depending on the design of the rivet mandrel and the user's wishes. Various positioning variants are explained further below.

[0013] The sealing ring material is designed to be very viscous or pasty, so that when the blind rivet is unloaded, the ring shape is retained, allowing a user to easily apply the sealing ring to the blind rivet, or allowing at least one sealing ring to retain its ring shape when the blind rivet is stored. However, the sealing material is sufficiently plastically deformable so that its shape is permanently changed when the sealing ring is pressed on. It is particularly advisable to select the viscosity so that the at least one sealing ring remains smooth after the blind rivet has contracted. Consequently, it should not be too viscous.

[0014] The sealing ring could, for example, be in an incompletely cured state during the production of the riveted joint, particularly after the blind rivet has been inserted into a rivet hole, and could harden after the blind rivet has contracted and the seal has been created. Consequently, sealing can also be achieved automatically during automated, tool-guided production of blind riveted joints. Both the application location and the application quantity are directly adapted to the requirements of the riveted joint being created. The sealing material is preferably curable in order to provide a homogeneous, durable base for a primer or paint. For example, the sealing material is based on polysulfides. A suitable hardener could include manganese dioxide or similar.

[0015] In an advantageous embodiment, the rivet mandrel comprises an external thread on an end facing away from the tool holder head, which corresponds to an internal thread in the sleeve, wherein the tool holder head has a first profile for transmitting a rotation of the tool to the rivet mandrel, which corresponds to a second profile of a tool. The rivet body is thus contracted by rotation of the rivet mandrel due to the intermeshing threads. After reaching a limit torque, which is matched to the mechanical properties of the rivet body and is achieved after complete contraction, the tool holder head breaks off. The tool holder head and the tool can comprise an elliptical drive system. Furthermore, the rivet body can have an opening on its side facing away from the tool holder head, through which the rivet mandrel can protrude during the contraction of the rivet body.

[0016] In an advantageous embodiment, the rivet mandrel has a circumferential collar that rests on the support collar of the rivet body. The circumferential collar, which can be arranged in the aforementioned section of the rivet mandrel or constitutes this section, presses into an opening in the support collar upon contraction. The opening of the support collar and the circumferential collar of the rivet mandrel could each have a chamfer that is matched to one another. This could give the circumferential collar a certain truncated cone shape, which is pressed into a similarly truncated cone-shaped opening. The rivet mandrel and the rivet body are thus centered relative to one another.

[0017] In an advantageous embodiment, the at least one sealing ring is arranged between the circumferential collar and the support collar. Starting from the rivet mandrel and the opening of the rivet body, the sealing material thus spreads radially outward and preferably largely completely covers the support collar of the rivet body.

[0018] In an advantageous embodiment, the at least one sealing ring is arranged between the tool holder head and the circumferential collar. A tool nose piece then acts on the at least one sealing ring during the contraction of the rivet body, so that the sealing ring is squeezed radially outward from the circumferential collar over the support collar of the rivet body. With this variant, it is important to ensure that the tool nose piece is free of contamination and, if necessary, is regularly moistened with a release agent. The release agent is preferably matched to the sealing material and designed to prevent adhesion of the sealing material.

[0019] In an advantageous embodiment, the support collar has projections on a side facing away from the tool holder head, which clamp onto the workpieces during contraction of the blind rivet to prevent rotation of the rivet body. The projections are pressed onto a surface of the workpiece facing the support collar by the tool and / or the circumferential collar, which presses against the support collar. This fixes the position of the rivet body on the workpieces, particularly in a rotationally fixed manner.

[0020] The sealing material can be automatically introduced into any gaps or spaces thanks to at least one sealing ring.

[0021] In an advantageous embodiment, the receiving collar has notches on a side facing the tool holder head, wherein the sealing ring is dimensioned such that the notches are filled with the sealing material after contraction of the blind rivet. The sealing material is also forced radially over the notches so that they are automatically wetted with the sealing material after contraction of the rivet body. It may be desirable to subsequently create a flat surface by filling. This can be done either for each riveted joint immediately following contraction or for an entire row of rivets or similar arrangement. The notches could be intended to engage with a non-rotating nose surface of the tool to counteract rotation.Since the notches are partially in contact with the nose surface, it may be necessary to smooth the sealing material with a spatula after removing the tool in order to then completely fill the notches.

[0022] In an advantageous embodiment, the tool holder head is free of cetyl alcohol. Cetyl alcohol is often used as a lubricant for fasteners and is usually applied to the entire fastener. To ensure a perfect seal of the riveted joint, it is advisable to avoid cetyl alcohol on the tool holder head, the circumferential collar, and / or the support collar. The blind rivet can therefore only be moistened with such a lubricant in a section facing away from the support collar, or the wetting can be removed in the area of ​​the support collar.

[0023] In an advantageous embodiment, the blind rivet has a resin coating. For example, aluminum-pigmented coatings according to EN 4473 could be used. A resin coating is particularly advantageous for the adhesion of the sealing material or a primer or paint layer.

[0024] In an advantageous embodiment, the at least one sealing ring is heat-curable, UV-curable, and / or moisture-curable. Curing of the sealing material can be controlled by appropriate application of heat or UV light. It is also conceivable to initiate curing through ambient humidity. Consequently, in the latter case, no further precautions need to be taken after the at least one sealing ring has been applied. The blind rivet could continue to be stored in a cooled state, thus interrupting the curing of the sealing ring made of a heat-curable sealing material, with curing occurring after the blind rivet connection has been created due to the ambient temperature.

[0025] In an advantageous embodiment, the at least one sealing ring can be filled with filler immediately after the blind rivet has contracted. The sealing material must therefore not be too viscous in its applied state, so that it can be manually distributed or smoothed with a spatula. However, it must be sufficiently pasty or viscous to retain its shape after filling and not flow or drip if the joint is not completely horizontal.

[0026] In an advantageous embodiment, the at least one sealing ring is a two-component mixture that is produced prior to the application of the at least one sealing ring or is realized in the form of two sealing rings that can be brought into contact with each other, with separate components that mix with each other upon contraction. Consequently, the two sealing rings form the curable sealing material only after the two sealing rings have been pressed together.

[0027] The invention further relates to a system for producing sealed blind rivet connections, comprising at least one blind rivet according to the above description and at least one tool connectable to the tool holder head. The tool is adapted to the design of the blind rivet and could be designed to exert a pure tensile force or to exert a rotational force. The tool could be electric or pneumatic.

[0028] In an advantageous embodiment, the tool has a tool nose piece that has a nose surface that can be brought into contact with the at least one sealing ring, wherein the nose surface is moistened with a release agent. The tool nose piece can have a rivet mandrel receptacle that is surrounded by an exemplary annular surface. This can press on the rivet body during contraction of the blind rivet. If the at least one sealing ring is located between the support collar and the tool holder head, the nose surface can press on the at least one sealing ring and consequently compress the sealing material axially and radially as described above. Sticking can be prevented by the release agent. It is preferable to regularly check the cleanliness of the tool nose piece and, for example, to regularly wipe it with a lint-free cloth and, if necessary, to moisten it with a release agent.

[0029] Furthermore, the invention relates to a method for producing sealed blind rivet joints of workpieces, comprising the steps of creating a rivet hole in the workpieces, inserting a blind rivet according to the invention into the rivet hole, and contracting the rivet body with a tool while compressing the at least one sealing ring. Subsequently, the sealing material could be filled with filler, if desired.

[0030] In an advantageous embodiment, the at least one sealing ring is a two-component mixture which is formed into an annular bead and placed on the blind rivet before the blind rivet is inserted.

[0031] In an advantageous embodiment, the at least one sealing ring is removed from an airtight and / or cooled packaging directly before inserting the blind rivet and placed on the blind rivet, or the blind rivet with the sealing ring attached is removed from an airtight and / or cooled packaging directly before inserting.

[0032] Furthermore, the method may comprise filling the sealing material after pressing the at least one sealing ring. Short description of the characters

[0033] The following examples are described in more detail with reference to the accompanying drawings. The illustrations are schematic and not to scale. Like reference numerals refer to like or similar elements. They show: Fig. 1 is a schematic representation of a blind rivet according to one embodiment in an uncontracted, neutral state and a contracted state. Fig. 2 is a schematic representation of a blind rivet according to another embodiment. Fig. 3 is a schematic representation of a support collar. Fig. 4 is a schematic representation of a system for producing blind rivet connections. Fig. 5 is a schematic representation of a method for producing blind rivet connections. Detailed description of implementation examples

[0034] Fig. 1 shows a blind rivet 2 for connecting workpieces 4a and 4b. These could, for example, consist of a metallic sheet or a plastic material, possibly with fiber reinforcement, and be used for an aircraft component or similar. The two workpieces 4a and 4b lie flush with one another and have a rivet hole 6 that extends completely through both workpieces 4a and 4b. The blind rivet 2 is inserted into the rivet hole 6 and is located on the left side of the drawing plane in a neutral (delivery) state.

[0035] The blind rivet 2 comprises a hollow, deformable rivet body 8 with a support collar 10 and an adjoining sleeve 12. Located within the sleeve 12 is a rivet mandrel 14, which includes a tool holder head 16 positioned outside the sleeve 12. The sleeve 12 has an internal thread 20 at an end 18 facing away from the tool holder head 16, while the rivet mandrel 14 has a complementary external thread 22 at this point. By rotating the rivet mandrel 14, while the position of the rivet mandrel 14 remains constant, the end 18 of the sleeve 12 is forced along the external thread 22 in the direction of the rivet bore 6. The sleeve 12 then deforms accordingly. This is shown in the drawing plane on the right-hand side. The deformation creates radial bulges 24 of the sleeve 12, which squeeze the workpieces 4a and 4b together with the support collar 10.

[0036] For example, the rivet mandrel 14 has a circumferential collar 26, which is pressed towards the support collar 10 during the contraction of the sleeve 12. Between the circumferential collar 26 and the support collar 10 is a sealing ring 28 made of a curable sealing material. After positioning on the blind rivet 2, the sealing material is in a state that allows an annular arrangement around the rivet mandrel 14, but is still sufficiently pasty or plastically deformable so that the material can be radially pressed during the contraction of the rivet body 8. During the contraction of the rivet body 8 and the pressing of the circumferential collar 26 onto the support collar 10, a sealing material layer 30 is produced by pressing the sealing ring 28, which extends completely over the support collar 10 if the sealing ring 28 is appropriately dimensioned.Any gaps or spaces between the outer workpiece 4a and the support collar 10, or between the support collar 10 and the circumferential collar 26, are thereby completely covered. It may be advisable to subsequently apply a filler or smooth the sealing material with a spatula.

[0037] On the right side of the Fig. 1 The tool holder head 16 is shown in a broken-off state, which is achieved by complete contraction of the rivet body 8 by exceeding a predetermined limit torque. The rivet connection is then complete. For example, the tool holder head 16 has a first profile 32, which is complementary to a second profile of a tool (not shown here) for connecting the tool and the tool holder head 16.

[0038] Fig. 2 shows an alternative design of a blind rivet 34, in which the rivet body 8 is designed in the same way, but the rivet mandrel 14 does not include a circumferential collar 26. The sealing ring 28 is arranged directly between the tool holder head 16 and the support collar 10. When the rivet body 8 contracts, a tool nose piece (see Fig. 4 ) is pressed onto the support collar 10 via the sealing ring 28, so that the sealing material is pressed.

[0039] In Fig. 3 The support collar 10 is shown in an oblique top view. On an underside 36 facing away from the tool holder head 16, the support collar 10 has, for example, several projections 38 distributed over the support collar 10. The projections 38 press into the outer workpiece 4a, thereby counteracting rotation of the rivet body 8.

[0040] It is also conceivable to provide notches 40 on the side facing the tool holder head 16, which are connected to the tool nose piece (see Fig. 4 ) can be brought into positive engagement to counteract rotation of the rivet body 8. By pressing the sealing material, the notches 40 are filled with the sealing material. Subsequent filling can completely distribute the sealing material in the notches 40.

[0041] Fig. 4 shows a system 42 for producing sealed blind rivet joints. Here, a blind rivet 34 is shown as in Fig. 2 which is coupled to a tool 44. The tool holder head 16 is inserted into a second profile 46 and can thereby be rotated by the tool 44. The tool 44 has a tool nose piece 48, which has a nose surface 50 which can be brought into contact with the sealing ring 28 and which is arranged, for example, in a ring shape around a receiving opening 52 of the tool 44. This can act on the sealing ring 28 when the rivet body 12 contracts, so that it, as in the lower illustration of Fig. 4 shown forms the sealing material layer 30. By way of example only, the nose surface 50 can have engagement elements 51 which engage in the notches 40 of the rivet body 8, if such are provided and desired.

[0042] Finally, Fig. 5a method for producing sealed blind rivet connections of workpieces and comprises the steps of preparing 54 the rivet bore 6 in the workpieces 4a and 4b, inserting 56 the blind rivet 2 or 34 into the rivet bore 6, and contracting 58 the rivet body 8 by the tool 44 while pressing the at least one sealing ring 28. The at least one sealing ring 28 can be a two-component mixture which is formed 60 into an annular bead before insertion 56 of the blind rivet 2 or 34 and placed 62 on the blind rivet 2 or 34. The at least one sealing ring 28 could, however, be removed 64 from an airtight and / or cooled packaging directly before insertion 56 of the blind rivet 2 or 34 and placed on the blind rivet 2 or 34 be placed 62 or the blind rivet 2 or 34 could be removed with the sealing ring 28 attached directly before insertion 56 from an airtight and / or cooled packaging 66.

[0043] After completion of the blind rivet connection, the sealing material can be filled 68. List of reference symbols

[0044] 2Blind rivet 4a, 4bWorkpiece 6Rivet hole 8Rivet body 10Support collar 12Sleeve 14Rivet mandrel 16Tool holder head 18End 20Internal thread 22External thread 24Radial bulge 26Circumferential collar 28Sealing ring 30Sealing material layer 32First profile 34Blind rivet 36Underside 38Protrusion 40Notch 42System 44Tool 46Second profile 48Tool nose piece 50Nose surface 52Hole opening 54Creating rivet hole 56Inserting the blind rivet 58Contracting the rivet body 60Shaping into a ring-shaped bead 62Placing on the blind rivet 64Removing the sealing ring from airtight and / or cooled packaging 66Removing the blind rivet from airtight and / or refrigerated packaging 68 spatulas

Claims

1. Blind rivet (2, 34) for connecting workpieces (4a, 4b), comprising a hollow, deformable rivet body (8) with a support collar (10) and an adjoining sleeve (12), a rivet mandrel (14) arranged in the sleeve (12) and extending through the support collar (10) with a tool receiving head (16), and at least one sealing ring (28), wherein the at least one sealing ring (28) is arranged between the support collar (10) and the tool receiving head (16), wherein the at least one sealing ring (28) consists of a hardenable and not completely hardened sealing material, wherein the at least one sealing ring (28) is arranged so that when the blind rivet (2, 34) contracts, it is pressed axially towards the support collar (10) by a tool (44) that can be connected to the tool receiving head (16) or by a section of the rivet mandrel (14), and wherein the at least one sealing ring (28) is designed to flow radially and axially into gaps and spaces on the support collar (10) and between the support collar (10) and the workpieces (4a, 4b) when the sealing ring (28) is pressed and to adhere there.

2. Blind rivet (2, 34) according to claim 1, wherein the rivet mandrel (14) comprises an external thread (22) at an end (18) facing away from the tool receiving head (16), which corresponds to an internal thread (20) in the sleeve (12), and wherein the tool receiving head (16) has a first profile (32) for transmitting a rotation of the tool (44) into the rivet mandrel (14), which corresponds to a second profile (46) of a tool (44).

3. Blind rivet (2, 34) according to claim 1, wherein the rivet mandrel (14) has a circumferential collar (26) which rests on the support collar (10) of the rivet body (8).

4. Blind rivet (2, 34) according to claim 3, wherein the at least one sealing ring (28) is arranged between the circumferential collar (26) and the support collar (10).

5. Blind rivet (2, 34) according to claim 3, wherein the at least one sealing ring (28) is arranged between the tool receiving head (16) and the circumferential collar (26).

6. Blind rivet (2, 34) according to one of the preceding claims, wherein the support collar (10) has projections (38) on a side (36) facing away from the tool receiving head (16), which jam with the workpieces (4a, 4b) when the blind rivet (2, 34) contracts to prevent rotation of the rivet body (8).

7. Blind rivet (2, 34) according to one of the preceding claims, wherein the support collar (10) has notches (40) on a side of the support collar (10) directed towards the tool receiving head (16), and wherein the sealing ring (28) is dimensioned such that the notches (40) are filled with the sealing material after the blind rivet (2, 34) has contracted.

8. Blind rivet (2, 34) according to one of the preceding claims, wherein the tool receiving head (16) is free of cetyl alcohol.

9. Blind rivet (2, 34) according to one of the preceding claims, wherein the blind rivet (2, 34) has a resin coating.

10. Blind rivet (2, 34) according to one of the preceding claims, wherein the at least one sealing ring (28) is heat-curable, UV-curable and / or moisture-curable.

11. Blind rivet (2, 34) according to one of the preceding claims, wherein the sealing ring (28) can be filled directly after the blind rivet (2, 34) has contracted.

12. Blind rivet (2, 34) according to one of the preceding claims, wherein the at least one sealing ring (28) is a two-component mixture that is produced before the at least one sealing ring (28) is attached or is realized in the form of two sealing rings (28) that can be brought into contact with components that are separate from one another and mix with one another when contracted.

13. System (42) for producing sealed blind rivet connections, comprising at least one blind rivet (2, 34) according to one of the preceding claims and at least one tool (44) which can be connected to the tool receiving head (16).

14. System (42) according to claim 13, wherein the tool (44) has a tool nose piece (48) which has a nose surface (50) which can be brought into contact with the at least one sealing ring (28), and wherein the nose surface (50) is wetted with a release agent.

15. Method for producing sealed blind rivet connections of workpieces (4a, 4b), comprising the steps: - Making (54) a rivet hole (6) in the workpieces (4a, 4b), - Insertion (56) of a blind rivet (2, 34) according to one of the preceding claims into the rivet hole (6), and - Contraction (58) of the rivet body (8) by a tool (44) while pressing the at least one sealing ring (28).

16. Method according to claim 15, wherein the at least one sealing ring (28) is a two-component mixture which is formed into an annular bead (60) and placed onto the blind rivet (62) before the blind rivet (2, 34) is inserted.

17. Method according to claim 15 or 16, wherein the at least one sealing ring (28) is removed (64) from an airtight and / or cooled packaging directly before the insertion (56) of the blind rivet (2, 34) and placed (62) on the blind rivet (2, 34), or wherein the blind rivet (2, 34) with the attached sealing ring (28) is removed (66) from an airtight and / or cooled packaging directly before insertion (56).