DE2446888A1 - RIVET - Google Patents

Description

PATENT LAWYERS 2446qQQ

HELMUT SCHROETER KLAUS LEHMANN

DIPL.-PHYS. DIPL.-INC.

Irwin E. Rosman an-hi-20

September 30, 1974-

Rivet

The invention relates to a rivet made of two parts and a tool for setting these rivets.

This rivet can be made of the material from which these rivets are made is to be relatively strong, even if it is used on soft components without them during setting the rivet will be damaged.

509882/0292

D-707 SCHWABISCH CMOND JOINT ACCOUNTS: D-8 MUNICH

Telephone: (07171) 56 90 Deutsche Bank AG Postal checking account H. SCHROETER Telegrams: Schroepat Munich 70/37 369 Munich Bocksgasse 49 Telex: (Sort code 700 700 10) 1679 41-804

Telephone: 10811) 77 89 K.LEHMANN Telegrams: Schroepat LipowikyttraßelO Telex: 5 212 248 pawe d

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In the case of riveted connections of plug tool components, materials of low strength are normally used for the rivets, such as aluminum or monel metals of relatively low strength. Materials of high strength, i.e. with a shear strength on the order of 2800-7000 kg / cm are not normally used for the critical, strong ones To rivet connections exposed to shear stress, as an upsetting head of a rivet made of a material of high strength Overstretch and damage the opening in the softer component lann. This has a very adverse effect on the construction. Currently, high strength pins in soft materials are used along with locking washers that are threaded or can be upset instead of rivets. Since an interference fit is desirable to reduce the fatigue of such connections To reduce, such pins are normally pressed into openings that are of a smaller diameter Have pen.

In US-PS J5 426 641 the upsetting of rivets from a High strength material shown with a full shaft when used with relatively soft aluminum surfaces, there is no adverse effect on the opening. This is done by using a specially shaped disc will. However, this washer must be used separately during the establishment of the connection, as with the use of a pen and the associated washers. The cost of the connection is increased and so is its manufacture difficult.

Rivets, made from a high strength material with full shafts and hollow ends, can be upset without detrimentally To influence the component in which the opening is located. However, if the hollow end of a rivet fails during upsetting

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is supported, internal displacements, eccentric head deformation and breakage of the hollow end can occur. Since the hollow upsetting end is not supported in a known rivet when it is deformed, the head can relatively cannot effectively withstand high tensile stresses that counteract the connection.

An object of the invention is to provide a rivet made of a material of relatively high strength in which the Upsetting head can be formed without any adverse effect on the opening, the upsetting head being essentially the same as solid as the preformed head can be made to withstand the tensile stresses that counteract the connection to be able to. A device for supporting the hollow end of the rivet during upsetting is also specified prevents internal buckling or eccentric deformation. In addition, it becomes a fastener of high strength specified, in which a separate disk or part to be handled separately are not necessary, so that the costs the production is reduced and this itself is simplified. Also, only one material should be included in the fastening device come into contact with the component, reducing the susceptibility of a galvanic destruction is reduced. Furthermore, a fastening means is specified, the shaft of which has a diameter is expanded, thereby biasing the opening during assembly, so that the joint fatigue is reduced will.

A solvent of the task is presented in the characterizing part of claim 1.

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The rivet according to the invention and the riveted connection are essentially used for the connection of components, such as e.g. Aluminum sheets and struts provided for plug tools, although they can just as easily be used with other components. The rivet assembly consists of a rivet and a core pin. The rivet is made of a material of high strength, for example in the order of magnitude from 2800-7000 kg / cm, preferably between 500 and 7000 kg / cm lies. The rivet has a shank that is substantially full in the area in which the thrusts are received. At A preformed head is formed at one end of the shaft and the other end has a tubular swaging section. The tubular upsetting section results from a recess, which begins at the end opposite the preformed head. The depth of the recess and thereby the length of the Upsetting section has a predetermined value in order to obtain the desired upsetting head. The length of the full shaft section is specified and depends on the total thickness of the components to be connected. The upsetting end, which is deformed to form an upsetting head, holds Together with the pre-formed head at the other end, the components are joined together by the rivet against loosening when a axial tensile force are connected. Since the tubular section easily becomes an upsetting head due to forces occurring at the end is deformed, no other overstretching or disruption of the opening occurs, even if a rivet is made of one material high strength is used to connect aluminum sheets

The core pin is inserted into the recess beforehand and supports the tubular section during the upsetting, to prevent its buckling or the occurrence of an eccentric deformation. The core pin remains after assembly in a middle layer around the upsetting head opposite the to support the connection occurring tensile forces.

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Since the rivet is the only part that comes into contact with the connected workpieces, compared to two parts in the commonly used shaft and washer assemblies, the connection itself is less prone to galvanic destruction. This is because they are less different Materials occur at the connection, and as a result fewer galvanic connections are possible. The manufacturing cost and the difficulty of installation becomes quite significant compared to the two-piece mounting arrangements with separate washers, reduced in that the upsetting head is an integral part of the rivet, and that the core pin can already be introduced into the shank section of the rivet beforehand.

In one embodiment of the invention, the full shaft is pressed together by forces at least at the end of the upsetting head formation exercised by the core pin. The resulting enlargement of the shaft can be an interference fit result or increase this in the case of an already existing press fit, in both cases thereby reducing the fatigue strength of the Connection is decreased.

Exemplary embodiments of the invention are based on the drawings shown.

Pig. I shows an axial cross-section of an arrangement with a countersunk rivets and an upsetting tool which is in the position before the upsetting process is inserted.

Figure 2 shows a cross section of the rivet assembly and tool the Fig.l after the upsetting process.

FIG. 3 shows a cross section of the rivet arrangement of FIG. 1 and after the upsetting process, which is indicated by broken lines or by solid lines, the components have a different thickness.

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Pig. 4 is a cross-section of a normal hollow-ended rivet and associated upsetting tool; the relationships before and after the upsetting process are shown.

Fig. € is a cross section of a known rivet with a hollow end, together with a correspondingly modified, known upsetting tool, the ratios before and are shown after the upsetting process.

Pig. (? is a cross section of another embodiment of the Rivet assembly together with an upsetting tool, showing the relationships before and after the upsetting process are.

Figure 8 is a cross section of one embodiment of the rivet assembly with a protruding rivet head

Figures 9 and 10 show an axial cross section and a right one, respectively Top view of a preferred embodiment.

Pig. II shows an axial cross-section of part of the rivet 9 after the upsetting process together with the associated Tool.

Fig. 12 shows another embodiment of a core pin.

13 shows a partial axial view, partly in cross section another embodiment of the core pin.

According to FIG. 1, the rivet arrangement is composed of a rivet 1 and a core pin 2. The rivet has a full shaft 3 with a central axis 3a, a preformed head 4 at a first end 4a and a hollow, tubular upsetting section 5 at the other end 5- of the rivet. The upsetting section 5 includes one A recess which is delimited by a circular, cylindrical inner surface 5b of predetermined length d in order to thereby

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to provide the desired upsetting head. The volume of the tubular Upsetting section 5 depends on the length, the * wall thickness and the Radii of the upsetting section.

The full shaft and the upsetting section have a circular, cylindrical outer surface 5c.

The diameter 6 of the core pin is so large that the core pin can be inserted into the recess. The diameter is about the same as the inner diameter 7 of the tubular Upsetting section and preferably slightly larger so that it fits tightly in order to prevent it from falling out. However a distance between the core pin and the surrounding inner wall can be allowed if the core pin is in a different way is held in the recess. An interference fit is preferred because it is easy to manufacture and is prone to falling out of the core pin is very reliable. By holding the core pin in the recess, the rivet can be handled as if it were a one-piece rivet. The core pin contacts the base 54 of the recess.

The rivet is preferably made of a material of high strength, that is to say a material of at least 2800 kg / cm shear strength. The deformability values of the material should be at least 10 % for the length and at least J> 0% for the reduction in cross section. Such deformability values are necessary in order to prevent the upsetting head from breaking during the upsetting process. The preferred value with regard to the change in length is 15-20 % and with regard to the reduction in cross-section it is approximately 40-60 %.

The rivet is inserted into the opening common to components 9 and 10 introduced. The openings in the components are aligned with one another.

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The shaft diameter 11 can be somewhat smaller than the diameter of the opening in order to simplify the insertion. A press fit would also be possible. The relationship and the ratios between these diameters are detailed described later.

The core pin 2 consists of a material 'whose compressive strength is essentially the same size or larger (it can also be a bit smaller) than that of the material from which the rivet was made. The thickness t of the core pin is smaller than the size d, so that a Section hj results, which receives part Ij5 of a tool and aligns this coaxially, which is done in that the diameter 12 with the diameter 14 of the recess until the surface 22 of the inner part 1 ^ 5 comes into contact with the surface 52 of the core pin.

The tool that is required for the rivet according to the invention: necessary force for upsetting achieved. When renting ■ the tubular upsetting end is first deformed and then, at least during the last upsetting process, a compressive force is exerted on the full shaft by the core pin exercised so that the full shaft is bulged during the termination of the upsetting deformation. As shown below is, this arrangement can also be used in a riveting operation in which no compressive force is applied to the core pin.

The outer part 15 of the tool comprises the inner part 1J> and moves forward towards the upsetting section 5. The upsetting causes a complete deformation of the tubular section. During this deformation, the section bulges outwards and bends in such a way that the upsetting head is created. This is best seen in FIG. The upsetting head formed in this way is not a setting head (although this depends on the

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relative dimensions of the upsetting section can occur), but instead a deformed or compressed annular shape occurs Training with an outer diameter Z (Pig.ll).

The inner part Ij5 of the tool is supported in its starting position by an elastomer or a spring 17 on a shoulder 16. The distance hp is fixed and depends on the size Yl ₁ .

According to FIG. 2, the forces F _{1 act} through the tools 18 and on the upsetting head end or on the end with the preformed head. The preformed head 50 is preferably curved in order to concentrate the force on the center of the rivet shank. The protruding head of FIG. 8 can also have such a curved shape. The elastomer 17 is compressed and the tool part 18 moves towards the inner part Ij, as a result of which the tubular upsetting section 5 is upset by the part 15 and a upsetting head 20 is thereby formed. When the distance hp becomes zero, ie when the tool surfaces 24 and 2J abut, the surfaces 21 and 22 on the outer and inner parts simultaneously exert a force on the upsetting head surface 25 and the core pin surface 52, which presses the shank together. This means that at the end of the upsetting process, the tool simultaneously exerts a force on the full shaft via the core pin, causing it to bulge, and on the stauoiikopf in order to develop it completely. This is an optional possibility, as already mentioned, and the bulging process can be suppressed by appropriately modifying or adjusting the tool.

Since the core pin is made of a material of high strength, the force on the core pin is exerted by the solid shaft is to be bulged, transferred directly to this without causing a greater diameter expansion of the core pin itself. The forces F i continue to increase and the diameter

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of the rivet shank expands to fill the opening 8 and expand until the desired interference fit is obtained. The extension is usually about 0.05 to 0.25 mm. Of the The term interference fit as used herein is defined as the difference between the diameter 11 of the rivet shank after the upsetting process is complete and the diameter of the opening 8 before the rivet was inserted.

According to FIG. 1, the core pin has at its axially opposite one another Areas of the same size radii 26 and 28, which are essentially exactly as large as the radius 27 of the recess, so that the core pin can also be arranged in reverse in the recess. This allows material 53 from the upsetting head to reach the edges grip around with the radius 28, making an excellent fastening device is formed between the core pin and the upsetting head. However, the ends of the core pin need not necessarily be designed identically. According to FIGS. 9 and 10, only one end of the core pin can be beveled. Such a As a result, the core pin cannot be used in any desired way, since its ends are not identical.

It can be seen that the core pin 2 laterally reinforces the tubular section during the formation of the upsetting head and prevents buckling or eccentric deformation of the head. The core pin reinforces the upsetting head by forces P after the riveting process has been completed. These forces P prevent a rotation and displacement of the upsetting head in the direction S under the action of tensile forces F _p which counteract the connection. As a result, the additionally supported upsetting head is essentially just as solid as the preformed head. You can see that the core pin can transfer the upsetting force for bulging the full shaft directly onto it, whereby a through-

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razor-like expansion of the shaft occurs. This creates a press fit which significantly reduces the fatigue life of the connection decreased. Such a bulge does not necessarily have to be made. The riveted connection does not lose their usability if the bulge is dispensed with.

The use of a core pin results in the possibility that rivets of a certain length can be used in a larger range R of changes in thickness of the components or, more precisely, changes in thickness at the connection points. The range of thickness change is defined as the difference in thickness from a maximum g to a minimum g ₂ , as indicated in FIG.

In the case of the rivets that are normally available, changes in thickness R of 0.8 mm are permissible. For a rivet with a diameter of 6, j5 mm, this permissible change corresponds to one eighth of the Shaft diameter. This change range R is shown approximately true to scale in Figure 3, and results from the Difference between the maximum and the minimum thickness g or gp, which a rivet of a given length L takes into account must be able to. In the present invention, all but the small sizes (l.h. approximately with a shaft diameter of 3.9 mm or less) the range of change should be at least 1.6 mm, i.e. roughly twice what was previously possible has been viewed. A rivet of a given length should be able to be used in a larger range of changes in thickness, because the sheet thickness is often within the manufacturing tolerances changes'. Sometimes sheets of increasing thickness are also used, so that the sheet thickness is in the range of the to be set Rivets changed, and it is evident that there is little benefit is to constantly have to use rivets of increasing length when the thickness increases at the rivet points of the components.

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The base area 5 ^ of the recess is arranged below the rear surface Jl (this is sometimes drawn as the exposed surface of the component) at a distance R with maximum thickness and is not above the surface 32 with minimum thickness. When properly installed, the base 54 is on or below the rear surface of the component, but never above it. So that the upsetting head rests against the surface 32 without breaking, it is only necessary for the tubular upsetting section and not for the full shaft to protrude from the surface 32.

The shape of the upsetting head will be different, but within permissible limits if the same rivet is used at different thicknesses within the permissible thickness range R. This is due to the fact that before the riveting a certain volume of the upsetting section of the length tu protrudes beyond the surface 32, which is different in size for the respective thickness. Nevertheless, you will always get a sufficient upsetting head, when the thickness is within the specified range. The ratio Z / D (Figure 11) is useful for obtaining one Rivet head, i.e. the ratio between the outer diameter of the formed upsetting head and the outer diameter of the full stem should be at least about 1.3. The core pin is the essential part that allows the rivet hollow end to be inserted is independent of a large range of thickness changes, without the possibility of a shaft bulging being lost.

The described mode of action of the core pin is an essential one Characteristic of the invention and thereby distinguishes it from known one-piece rivets with a hollow end. This will emerge even more clearly in the discussion of the known rivets.

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In Figure 4 is a normal rivet 33 with a hollow end and a normal upsetting tool 34 and 35 before and after Upsetting process shown. The two different states are indicated above and below the center line. The depth d the recess in order to obtain the necessary volume for the upsetting head is indicated. Without a core pin one can easily get one Buckling or eccentric deformation of the hollow end 5 'occurs, as indicated by the broken lines. Even when the head 36 has been upset satisfactorily, As shown below the center line, it is not supported from the inside and can therefore easily be inserted into the Dodge direction S under an axial force Fp. One sees also that the force P- are not transmitted to the shaft can to bulge this out.

FIG. 5 shows a known rivet 33 with a hollow end before and after the upsetting process. The thickness g was chosen so that the tool surface 37 can contact the rivet surface 38 after the upsetting process in order to bulge the rivet shank. The surface 39 of the recess lies a distance hu above the surface 3I, which corresponds to the thickness of the upsetting head 40. The hollow section is pressed over the area of the full shaft protruding by a distance h ^, and the breaking of the upsetting head, which can easily occur here, is indicated by the line 41. Here, too, there is no inner support that prevents the hollow shaft end from buckling during the upsetting process.

FIG. 6 shows a known rivet 33 with a hollow end before and after the upsetting process. A modified one known upsetting tool 42 has a nose portion 43 the length hp-, which after the formation of the upsetting head with the surface 44 comes into contact to cause expansion of the shaft.

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It can be seen that only a partial support of the hollow end is achieved during the upsetting process, and that again the The upsetting head is not supported from the inside and is consequently easy when axial tensile forces Fp occur in the direction S is bent.

Another embodiment of the invention is shown in FIG. where the ratios are given before and after the upsetting process. The circumferential groove 46 on the core piece 45 represents represents a means of contacting surface 47 of the upsetting portion in securing intervention to come. The material of the hollow end penetrates the groove and forms a seal.

FIG. 8 shows a rivet 48 according to the invention with a protruding one Head 49j before being upset in a riveted joint has been. The rivet connection with such a rivet is made in the same way as with the flat-headed rivet according to Figure 1.

FIGS. 9 to 11 show a rivet 1 according to FIG. 1, in which a different core pin 60 is used. This core pin has one area which has a circular, cylindrical outer surface 61 and another area 62 which is beveled. The beveled area has a circular, flat abutment surface 6j> at its free end, which faces away from the base surface 54. The cylindrical surface 61 preferably fits tightly in the recess so that it is retained in it. At the other end, the core pin carries an abutment surface 64 which abuts the base surface 54 of the recess. The various reference letters given in FIGS. 9 and 11 relate to dimensions that follow a little later.

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Dimension line 65 corresponds to the axial position of the base area. Dimension lines 66 and 67 indicate the position of the exposed surface and the rear surface 68 (Figure 11) of the workpieces at minimum and maximum thickness. The meaning of other reference numbers and letters can be found directly in the drawings.

In FIGS. 10 and 11, one is provided with a core pin 60 Rivets 1 arranged in components 9 and 10. Components 9 and 10 are only partially shown in Figure 1-1 and it is obvious that the arrangement corresponds to that of Figure J5. The upsetting head 69 in FIG. 11 is a more precise representation of the upsetting head formed by this invention. One recognizes a barrel-like deformation with a fold 70, so that a button-like Head with an outer diameter Z is formed. However, it depends on the dimensions used for a setting head possible (i.e. an upsetting head in which during compression no folding occurs) that it is formed approximately in accordance with FIG. This depends essentially on the length, the wall thickness and the diameter of the tubular section. A shorter end with a thicker wall will more likely have a compressed end.

In the various embodiments, the upsetting head should preferably obtained a deformation according to Figure 11, although this is not a necessary limitation of the invention. It was observed that a certain amount of compression or setting in the sense of a deformation of the metal occurs at the upsetting head 69, so that the outer surface 7I of the head has the shape of the attack surface 21 of part I5 of the tool assumes. The end of the upsetting head engages around the beveled section of the core pin

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and prevents it from falling out after the head is formed has been. As a result, the amplification already explained also occurs at the same time. Transfers for reasons to be explained the inner part I3 of the tool no force from the core pin, when a substantial extension of the shaft is not desired. Then there is no contact with the core pin either necessary. In another way of arranging the rivets, the inner part 13 of the tool can extend axially along the axis 73, so that contact with the core pin occurs and forces through the core pin at least at the end of the upsetting process be exercised to expand the shaft. This is used when at the beginning the rivet has a certain distance from the has opening. A bevel 90 on the inner part I3 of the tool (see FIG. 11), a cylindrical section 91 is preferably adjacent. The cylindrical section 9 * can in the end of the 'upsetting portion of the rivet can be used to align the tool relative to the axis of the rivet when on no stronger deformation force exerted by the part I3 on the shaft shall be. The bevel prevents mutual interference at the rivet end when this is set without an axial force is exerted on the core pin.

In Figures 12 and 13, other types of core pins are shown. The core pin 75 according to FIG. 12 has a cylindrical circular outer surface 76 , an inclined surface and a second cylindrical surface 78 with a smaller diameter. The surfaces 76 and 77 achieve the same effect as the surfaces 61 and 62 according to FIG. The additional cylindrical surface 78 can provide additional guidance for the end of the upsetting section as it moves inward during the formation of the head. By

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the beveled section 77 shows in a very good approximation the path that the rivet end will take when pressed together, if it were not supported. The dimensioning of the core pin according to Figure 12 is made in this regard.

At the end of the core pin 75 is a small, conical projection educated. In some embodiments of the invention, at which the rivet by a backward extrusion or duror. a Impact method is produced, the punch used to create the recess has a small countersunk bevel and a similar lead. It is not necessary that the core pin with the base 5 ^ has an absolute surface contact, if However, if this is desired, the projection can be formed according to the base shape. From yet to be specified The reason is to start with a perfect surface contact between the butt end of the core pin and the base in the recess unnecessary.

A differently designed core pin 8o is shown in FIG. which has two cylindrical surfaces 31 and 82 which separated from one another by an inclined surface 83 are. The difference between this embodiment and the according to Figure 12 is essentially the difference between the axial lengths of the two cylindrical surfaces. One can see that, if it is desired to hold the core pin more firmly in the rivet, this can be done by having the chamfered upset portion 84 deformed to encompass the smaller cylindrical surface. The resulting overlap 85 holds the Core pin tight.

Looking at the properties and use of the rivet arrangement, one can distinguish four different types:

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1. No substantial stem- Original interference fit, expansion.

2. No significant shaft expansion. Originally no interference fit.

3. Shaft expansion. Original press fit.

4. Shaft expansion. Originally no press fit.

In cases 1 and 2, there is no substantial expansion of the shaft that would create a press fit or an existing one would reinforce. Here the connection would be made by using the tool according to FIG. 11, the outer Part 15 of the tool on the rivet engages the upsetting head However, no axial force is exerted on the core pin by the inner part that would be sufficient to produce any substantial To cause deformation of the full shaft. Of course, there would also be a slight deformation of the shaft here because of the upsetting head occurring forces take place, although in the end no direct pressure is exerted on the core pin by the tool. the Deformation of the stem occurs because at least some force is transferred to the stem itself, although not directly takes place by a force acting on the core pin. However, the shaft enlargement plays the role of the engaging for upsetting Force does not play a significant role and is much weaker than the stem deformation that occurs when it is substantial Force is applied directly to the core pin by the tool. The term "stem extension" refers to an extension the one engaging directly on the core pin through the tool

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Force is effected and therefore comes into play on the full section of the shaft through the transmission through the core pin, and not on the deformation that occurs indirectly because the force acting on the material of the upsetting head is caused by the core pin is transmitted.

In cases J5 and ^ there is a significant expansion of the full shaft. In case 3 there is already a press fit between the rivet shank and the interface before the rivet is set the opening before. This is reinforced when the shaft is expanded by the force acting on the core pin at its end. In case 4 there is no press fit at the beginning, but it arises by the force acting on the core pin. The strength of the interference fit is also determined by this force. In that moment, when a force is exerted on the core pin, the upsetting head is almost completely formed. The force on the core pin occurs simultaneously with the final phase of the formation of the upsetting head so that when the shank is bulged and consequently shortened somewhat, the outer part of the tool continues to move and the deformation of the upsetting head continues, so that a firm connection is formed.

Refer to the dimensions in the table for the rivet and the core pin refer to an example corresponding to case 1. The specialist will have no difficulty making small sizing changes as may be necessary in order to achieve an adaptation to a use in which a substantial expansion of the shaft in addition to the formation of the Upsetting head is desired. The four cases given have significant advantages. In case 1, the advantage is that here an automatic tool can easily be used, by means of which an interference fit in one can be achieved quickly and immediately

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dimensioned hole can be achieved. The upsetting head will then with little force, as is only necessary for this, formed without a significant bulging of the shaft occurs.

Case 2 is useful in a similar way. This is particularly advantageous for arrangements that are made by hand, since the rivets are without Difficulties can be introduced into the opening. However, this case will only occur if, when connecting the Components a distance between the shaft and the inside of the opening is permissible. This is the case with many designs and with regard to the strength of the upsetting head in this application, it can be imagined that this type of arrangement will be common will be used.

In case 3 there are the same advantages as in case 1, but there is an additional advantage that consists in the substantial expansion of the shaft when a stronger press fit is desired.

In case k , the advantage is that there is no press fit at the beginning of the insertion of the rivet, which makes this insertion easier, but a press fit is then achieved by a substantial expansion of the shank.

The deformation forces in case 1 are significantly smaller than in known upset rivets that have a fixed upsetting head. For example, to manufacture an upsetting head according to case 1, a pressure force of approximately 2700 kg is required for a rivet with a diameter ratio between the damming head and the shank Z / D of 1.3, which is made of titanium and has a diameter! of 3> 9 mm. For rivets with diameters of 4.7 mm, 6.3 mm,

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7.8 mm and 9.4 mm become forces of 3000 kg, 6700 kg, 9960 kg or 131 ^ 0 kg are required.

A consideration of the various cases shows that the rivet is well suited for making connections in which the specific shear strength of the rivet material is greater than that of the components. As a result, it can be said that the rivets are off are made of a material of high strength. In practice, especially in aircraft construction, this means that the specific Shear strength is over 2δ00 kg. However, v.-ird with most of them Cases the shear strength; in the size of 630c '.: is? lie. These fourths are far above those of e.g. aluminum. Examples of suitable high strength materials are given below the specified:

Material Specific shear strength (kg / cnf

Monel Metal Approximately 3500 Titanium Alloys:

8-8-2-3 63OO-7000

Beta C 6300-7000

Beta III 63OO - 7000 steel alloy:

A-286 63OO - 7000 _:

Of course, other materials can also be used instead, since those given above are only examples and not Represent exclusivity.

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Advantageously, the core pin made of a titanium alloy 6AL- ² IV (according to the American standard), which has been appropriately treated to achieve the desired strength, can be used together with rivets made of a titanium alloy. The core pin may be made of suitably treated A-286 steel alloy with a rivet of the same material.

The selection of the material for the core pin in relation to the material of the rivet must be made so that the core pin material has a compressive strength which is essentially exactly as great as that of the material of the rivet.

In the following table, dimensions are given which help those skilled in the art to produce a rivet according to FIG. The proposed Materials for such a rivet are:

For the rivet, the titanium alloy 8-8-2-3 with a specific shear strength of approximately 600 kg / cm.

The same alloy is used for the core pin, but

2 aim for a higher shear strength of about 7000 kg / cm has been treated.

The dimensions in the table are given in centimeters. The line numbers indicate the nominal rivet shank diameter as a multiple of 0.8 mm.

If the ratios are used as indicators, the following ranges are suitable, their most favorable values in the table are specified.

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E / 0 below 1.5. » preferably between 1.0 and 1.2;

E / C from about 1.7 to about 1.8;

C / D from about 0.6 to about 0.7;

P / E from about 0.4 to about 0.6;

P / D from about 0.45 to about 0.55.

The base 54 will normally not be spaced any larger than 1.9 mm from the surface of the component on which the Upsetting head is arranged.

T nom. ABE E. L L E. E. ¹ F. 18th A. X 12th Y , 33 Line Diam. D. C. C. 51 91 , 33 number 4.0 1,738 4, 55 2, 35 2.36 1, 91 0 , 33 -5 4.8 4.14 1,740 2, 62 5, 26 2, 19th 2.74 1, 91 C. , 33 -6 6.4 4.8 1,745 3, 02 6, 96 3, 00 3.61 1, 91 0 , 33 -8th 8.0 6.32 1,750 3, 99 8th, 71 4, 4.52 1, 0 -10 9.6 8.00 1,740 4, 98 K), 44 5, 5.43 1, 0 -12 E. 9.50 5, 99 P. F. Line D. C. E. D. number 1.1 D. .480 .528 -5 ' 1.1 • 630 .478 .524 -6 1.1 • 630 .481- • 530 -8th 1.1 • 63Ο .481 • 530 -10 1.1 • 63Ο .479 .526 -12 • 630

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The core pin forms a weak interference fit together with the recess so that it cannot fall out when the rivet assembly handled before insertion. From the table and FIG. 9 it follows that the size X corresponds to the distance from the maximum thickness (i.e. between the exposed surface of the workpiece at the upsetting head end and the base 54 of the recess) and 'the size Y corresponds to the distance of the minimum thickness.

The ratios E / D, E / C and C / D are related to the mode of operation the rivet of importance. It has been found that rivets in which the corresponding ratios are not taken into account were, not optimally and often at all uncomfortable are . These ratios do not depend on the rivet material used. If you take them into account according to the invention, a useful rivet arrangement is obtained. These ratios essentially relate to the fact that a suitable volume of material to form a proper upsetting head within the whole. Di.ckenbereich.es provided wire. These ratios can deviate somewhat from the specified fourth, but experience has shown that a good riveted joint is obtained when these relationships are taken into account.

Furthermore, the ratio E / D should be less than about 1.5. It turns out that this relationship to achieve a good Rivet connection is important.

In accordance with aircraft manufacturing requirements, the ratio C / D will be at least about 1.3. An upsetting head, which does not meet this requirement are generally not to be used in the aviation industry. *

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The rivet can normally be in a thicker range of the components at the rivet point of 0.5D t> 4D is used v / earth.

The characteristic for determining the axial length of the core pin is that the core pin must be long enough, darr.it a substantial portion of the core pin is the inner diameter of the upsetting head and thereby prevents rotation of the upsetting head in the sense of unwinding. It means that as a result, an inward folding is prevented when tensile forces occur, which reduces the strength compared to the axial, the connection counteracting forces reduced. During an initial full contact between the butt surface of the core pin and the base area of the recess, from a practical point of view, probably the cheapest however, this is not a requirement. Because the material of the core pin is at least as strong, if not even is stronger than that of the rivet, the result is that when the core pin presses against the mismatched base, the on one Pressure applied to the small contact area causes the material of the rivet to flow and, consequently, a larger contact area developed between the rivet and the core pin. Ultimately, both surfaces become essentially perfect touch. As a result, it is possible to design the core pin according to FIG. 12 with a projection that is initially against the relative flat base. Or you can with a core pin with a flat abutment surface according to Figure 12 this against a Let a rivet in accordance with FIG.

If the shaft is to be extended, rr.an proceeds so that first most of the upsetting head is formed and then pressure is applied to the core pin during the final phase in order to to bulge or enlarge the full shaft. One can see that

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the strength of the interference fit depends on the force exerted. This is the case with FIGS. 1 to 3. Should be a major expansion of the shaft are not desired, then nan will be happy Figure 11 proceed where the inner part of the tool meets the core pin is not in contact and only the outer part of the tool attacks the rivet in order to set it. However it is often indicated, the inner part of the tool for a centering and guidance of the outer tool part relative to. tubular End to use. In such a case the tool is reshaped so that the inner part is the beginning of the very outer one Part of the tubular end is encompassed, wherein it is designed so that it has the formation of a correct upsetting end not affected.

It can be seen from the drawings that the shaft is largely full in order to be able to absorb thrust loads. This is special from the Figure 8 can be seen, which shows a rivet with a protruding head, but this also applies to the countersunk or flat head rivets to where some thrust load is actually being absorbed by the head itself. The depth Y, which corresponds to the minimum thickness, in which the base area comes to lie within the component, and the size X, which corresponds to the greatest thickness, is relative make small sections of the entire length of the rivet. They are in place to ensure that there is only one tubular section protrudes over the component. This prevents the conditions occurring in accordance with FIG. 5 in which the breaking of the Head can arise.

From the explanations it follows that a rivet is made from a material of high strength and put together

can be used with a component made of a material of relatively low strength without damaging the component. This can be done with or without a press fit by the expansion

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of the shaft is formed. This rivet according to the invention differs differs from known tubular rivets in that the largest part of the shaft within the component fully .and not is tubular, and that the tubular section provides sufficient material to provide a suitable upsetting head in the entire thickness range to allow. Relatively little forces are required to shape the head. The bulging or widening of the shaft depends only on the acting force and not on a displacement of the tool.

509882/0292

Claims (16)

- 28 - an-hi-20 PATENTANS P R-U CHE 1. Rivet made of two parts with a central axis, thereby g e - indicates that the rivet at a first end ■ (4a) has a head (4) and an adjoining unc, with the Head has an integrally formed full shaft (j5) to which a tubular upsetting section (5) integrally rr.it derr. full shaft adjoins the other end (5a), the full shaft and the tubular upsetting section having a c.'u.? ero circular cylinder surface, and d & l the tubular. Upsetting section (5) has an inner recess at the other end of the rivet and a base surface. (5 ¹ O within the recess at the end of the full shaft, and that a core (2) is arranged within the recess, the core {2) through an abutment surface (52) can be brought into contact with at least part of the base surface (5 ^), and since: 3 the volume of the tubular upsetting section (5) is sufficient to form an upsetting head, the largest diameter of which is at least 1.3 times as large as the The shaft diameter is when the rivet is inserted in an opening (8), the length of which corresponds to the maximum clamping length of the rivet, whereby the base surface (5 ² O is arranged so that it does not protrude from the workpiece when the rivet is in the Area of the minimum clamping length is used, wherein the Druckerstigdes material of the core pin is at least as large as that of the material of the rivet. 2. The rivet of claim 1, wherein the ratio of the axial length (d) of the tubular upsetting portion (5) to the diameter of the full shaft (3) is less than about 1.5. 509882/0292 - 29 ~ an-hi-2C 3. rivet according to any one of the preceding claims, characterized marked that the core pin in the Recess is retained. 4. Rivet according to one of the preceding claims, characterized in that the core pin (2) rr.it is arranged in a press fit in the recess. 5 rivet according to one of the preceding claims, characterized in that that the core pin (2 'is an abutment surface (52) which points from the base (54), when the core pin (2) is in the recess. 6. A rivet according to any one of the preceding claims, characterized in that the core pin [2. " zv / ei has substantially identical abutment surfaces on each of its axially opposite sides. 7. Rivet according to one of the preceding. Claims, characterized in that the core pin (2 ": has a circular cylindrical wall (91) and an adjoining oblique section (9C). 8. rivet according to one of the preceding claims, characterized indicates that the core pin (2) has a second cylindrical section (78) on the opposite and smaller side of the first cylindrical section inclined section (90). 9. Rivet according to one of the preceding claims, characterized in that the core pin (2) has a pair of circular cylindrical sections (S1, 82), vcn of which 50 9882/0 292 - 30- an-hi-20 one (8l) has a larger diameter than the other. 10. A rivet according to any one of the preceding claims, characterized in that the tubular upsetting section (5) is deformed, whereby the core pin (2) can be retained in the recess. 11. rivet according to one of the preceding claims, characterized by the following ratios: Ξ / D between about 1.0 and about 1.2; E / C between about 1.7 and about 1.8; C / D between about 0.6 and about 0.7; P / E between about 0.4 and about 0.6; F / D between about 0.45 and about 0.55 12. Rivet according to one of the preceding claims, characterized in that that the material from which. the rivet is made to have a specific shear strength is between approximately 3500 and 7,000 kg / cm. 13. rivet according to claim 12, characterized geke η η ζ eich π e t, that the shear strength is between about 630c and 7000 kg / cm. 14. Tool for upsetting the tubular! Upsetting section a rivet with a central axis, a full one. Shank and a recess at the end of the upsetting section in which a Core pin for receiving and transmitting an axial force is arranged on the full shaft, characterized in that a part (15) of the tool has an annular, has beveled end surface (21), whereby on the upsetting portion (5) an engaging at its end and inward pressure force can be applied, and that there is an inner part (I3) with an outer surface (23) coinciding with the axially outermost one. SAD 509882/0292 2U6888 - 31 - an-hi-20 Part can be brought into supporting and centering engagement. 15 · Tool according to claim 14, characterized in that it is that an axial compressive force can be applied to the core pin (2) through the inner part (13). 16. Tool according to claim 15, characterized in that a device (17) is arranged between two parts (I3, 18) of the tool, through which a force on the core part (2) through the inner part (13) ^ z "· * ογ ·> the tool can only be applied if the outer part (15 <has at least partially formed the compression cap. 509882/0292