EP0689888A1 - Blind fastener - Google Patents

Abstract

The setting tool comprises an adjustable mouth piece (7) which is shaped as a polygon. The mandrel guide channels (8) extend from one side (14) to an opposite corner (15). The mouth piece is rotatable about a mainly stationary axis, which extends at right angles to the drawing direction of the drawing mechanism (3). The mouth piece has bearing journals, which project at right angles to the mandrel guide channels. The journals support the mouth piece on a bearing section of the housing (2). The drawing mechanism is moveable relative to that housing section. <IMAGE>

Description

The invention relates to a blind fastener setting device with a pull mechanism and an adjustably mounted mouthpiece, which has a plurality of mandrel guide channels, one of which can be aligned with respect to the pull mechanism.

Blind rivets are mainly used as blind fasteners. However, this also includes blind rivet nuts.

The most common rivet dimensions today are between 2.4 and 5 mm in diameter in different materials. The diameter of the rivet mandrels, which break off at a predetermined breaking point when the required setting force is reached, have diameters of 1.5 to 3.2 mm. Therefore, the mouthpieces on which the rivet head is supported when setting must be adapted to the mandrel diameters. Accordingly, the Bores of the mouthpieces used for the most common rivets in the range from 1.9 to 3.6 mm. If the bore or the mandrel guide channel is too small, larger rivets cannot be processed because the thicker mandrels do not fit into the mouthpiece. If, on the other hand, holes that are too large are used, the thinner mandrels fit into the mouthpiece, but processing the blind rivet is problematic. Firstly, the mandrel can be pulled through the rivet without tearing. On the other hand, annular impressions and deformations can occur on the visible rivet head because the necessary contact surfaces are not available. In short, the mouthpiece must always be selected to match the rivet size used.

Replaceable mouthpieces are therefore provided in most setting tools. However, a tool is usually required to change the mouthpiece. The number of work steps when changing a rivet size is considerable. The mouthpiece must be removed using the tool, a suitable mouthpiece must be selected and installed using the tool. The removed mouthpiece must be stowed so that it is not lost. In applications where a frequent change of rivet sizes is necessary, the set-up time required increases considerably.

US 4 648 259 shows an adjustable mouthpiece for blind rivet setting tools. The mouthpiece consists essentially of two jaws. Each jaw has a triangular recess, so that the opposing jaws together form an approximately rectangular or square mandrel guide channel. The two cheeks taper towards the tip. With the help of a union nut, they can be brought closer or closer together in the area of their tip by tilting. With a larger diameter of the mandrel guide channel This creates a slit between the two jaws, which is clearly visible on the rivet head. When the mandrel guide channel is reduced, the two contact surfaces, which are still coplanar in the case of large diameters, are at an angle to the rivet head. On the one hand, this leads to a visible imprint on the rivet head and on the other hand also worsens the setting behavior.

EP 0 137 817 shows a blind fastener setting device of the type mentioned at the outset. The mouthpiece can be rotated about an axis which includes an angle of approximately 45 ° to the pulling direction of the pulling mechanism. The mandrel guide channels are accordingly inclined by this angle with respect to the axis. By turning the mouthpiece around the axis, the individual mandrel guide channels can be brought into alignment with the pulling mechanism. The disadvantage here is a relatively high manufacturing effort for the mouthpiece and housing. A relatively large size is also required for the housing. In particular, its diameter must be chosen accordingly large. This makes the device heavy and unwieldy. In many cases rivets are required which have excess length rivet mandrels so that the pulling mechanism can grip the mandrels passed through the mouthpiece and the necessary housing parts.

The invention has for its object to enable a quick change in the rivet mandrel sizes.

This object is achieved in a blind fastener setting device of the type mentioned in that the mouthpiece has the shape of an odd-numbered polygon in section, the mandrel guide channels running from one side to the opposite corner.

The term "corner" simply means the transition between two sides. It is not necessary that the two sides forming the corner meet here at a certain angle. A transition, for example in the form of a curve or a polyline, is also possible. The use of an odd-numbered polygon makes it possible to pass a large number of mandrel guide channels through the mouthpiece without the diameters influencing one another. At one end of each mandrel guide channel, the side of the polygon defines a flat surface against which the rivet can lay when it is set, without being provided with any profiles or impressions. The overall height of the mouthpiece does not exceed that of conventional mouthpieces, or only to a small extent. You can therefore process normal rent without long rivets. The increase in weight is practically not noticeable. The exterior dimensions of the device can be left more or less unchanged.

The polygon is preferably designed as a regular polygon. This facilitates the manufacture of the mouthpiece and the storage of the mouthpiece in the device. Regardless of the size of the mandrel guide channel, the mouthpiece can always be handled and employed in the same way.

The mouthpiece can preferably be rotated about an essentially stationary axis which runs perpendicular to the direction of pull of the pulling mechanism. The mouthpiece therefore remains essentially stationary in the device when being adjusted. This drastically reduces the risk of loss. The setting is also simplified because a certain orientation of the mouthpiece is predetermined by the fixed storage. The rotatability increases the ease of use considerably.

The mouthpiece preferably has bearing pins projecting perpendicularly to the mandrel guide channels, by means of which it is supported on a bearing part of the housing, in contrast to which the pulling mechanism can be moved. The housing thus absorbs the forces exerted by the pulling mechanism on the rivet mandrel via the mouthpiece. The bearing journals are used on the one hand to transfer force from the mouthpiece to the housing, and on the other hand to adjust the mouthpiece.

In a preferred embodiment, the trunnions are round. In another advantageous embodiment, at least one of the bearing pins has the shape of the polygon with reduced sides in section, the polygon of the pin being rotated relative to the polygon of the mouthpiece by an angle which is 180 ° divided by the number of sides of the polygon, and the pin rests on a surface that extends substantially perpendicular to the direction of pull. With the help of the polygonal pin, a fixation of the mouthpiece can be achieved in the assumed position. The side of the peg polygon, which rests on the surface, is essentially parallel to the side of the mouthpiece, which forms the contact surface for the rivet head in this position, because of the angular position of the peg relative to the mouthpiece. Since the surface extends essentially perpendicular to the pulling direction, ie the normal vector of the surface runs parallel to the pulling direction, the force acting on the rivet head is completely absorbed here. The side of the cone polygon lying against the surface creates an increased resistance against twisting of the mouthpiece. The mouthpiece must be displaced at least a little so that the side of the pin can stand out from the surface.

In the ready state, the mouthpiece preferably projects with a corner of the polygon into a recess in a housing part and lies against the housing part with at least part of the sides enclosing the corner. "Ready state" means the state in which the device can accept a blind rivet (or a blind rivet nut) in order to then set it. The pull mechanism is in its foremost position. In this state, the mouthpiece must be fixed in such a way that no inadvertent adjustment occurs, that is to say the desired diameter of the mandrel guide channel is actually available. As soon as the pulling mechanism has gripped the mandrel, this fixation is no longer necessary to this extent because the rivet mandrel holds the mouthpiece in the appropriate orientation. The corner of the polygon is used to fix the mouthpiece in the ready state. Because this corner protrudes into a recess in the housing part and at the same time the two sides enclosing the corner at least partially abut the housing part, inadvertent rotation of the mouthpiece is practically impossible. In addition to the advantage of the polygon with the odd number of pages that a plurality of mandrel guide channels can be provided here, this polygon also has the further advantage that the fixing is greatly simplified without additional measures.

The housing part is preferably movable relative to the housing. This makes it easier to adjust the mouthpiece. You only have to move the housing part so far that the corner protruding into the housing part can be moved out of the housing part. When the housing part is moved back to its original position, the mouthpiece is fixed.

In this case, means are preferably provided which bring about an increased frictional connection between the housing part and the housing. The housing part therefore normally remains in its set state due to the increased friction. To move it, external forces are necessary, which must be applied, for example, by an operator. However, an inadvertent displacement of the housing part relative to the housing, for example in the course of a work process, can be largely prevented.

In the ready state, the housing part is advantageously acted upon by a restoring force. The restoring force thus secures the mouthpiece against twisting because it presses the housing part against the mouthpiece.

It is particularly advantageous here that the restoring force acts on the housing part via the pulling mechanism. In any case, a restoring force is required for the pulling mechanism, which is normally applied by a spring, in particular a compression spring. You can now use the force of this spring to press the housing part against the mouthpiece. In the ready state, the desired fixation of the mouthpiece is achieved. In order to adjust the mouthpiece, the pulling mechanism must be moved back a small distance. This can be done either by hand or by motor. The housing part is then released so far that it can be moved relative to the housing.

The housing part is preferably designed as a jaw opening device for the pulling mechanism. When the pulling mechanism is moved back to its front end position, i.e. to the ready state, its jaws have to be opened in order to be able to dispense the old rivet mandrel and to take up a new rivet mandrel. If now the housing part is designed so that it can simultaneously serve as a jaw opening device, it is ensured that the housing part is always pressed against the mouthpiece with the necessary force in the ready state. As soon as the mandrel can be removed, the operator knows that the fixation of the mouthpiece has been reached again.

Advantageously, the mouthpiece is formed by a spherical disk which is essentially symmetrical on both sides of the mandrel guide channels and has a substantially flat flattening on its circumference in the region of a mouth of each mandrel guide channel. The mandrel guide channels lie in a plane that forms the central plane of the spherical disk. When a ball or spherical disc is flattened, the flattening takes on a circular shape. However, this is exactly the shape that is desired as a contact surface for the rivet head. A spherical disc can be manufactured relatively easily, for example as a turned part. The flats can be attached just as easily, for example by milling. When designed as a spherical disc, however, the shape of the polygon can only be seen in the central plane. On the two end faces of the spherical disc, only a circle can be seen from the outside. Accordingly, if this is used, the recess in the housing part in the region of the end faces of the spherical disk can be provided with corresponding inner radii.

The width of the spherical disk preferably corresponds essentially to the length of one side of the polygon. The mouthpiece is kept as small as possible with given dimensions. The flats then have a diameter that corresponds exactly to the width of the mouthpiece or the spherical disk. The individual flats then collide at the corners of the polygon.

Strictly speaking, this only applies to the middle level. The further you get outside, the greater the transitions in the form of curves.

A union nut is advantageously provided which holds the mouthpiece in the housing. Such a union nut can be easily screwed on. But it gives the inside of the mouthpiece the necessary freedom of movement so that it can be adjusted accordingly. The union nut preferably acts only on the bearing journal, so that the mouthpiece can be freely rotated when other fixings are removed, but is nevertheless held captively in the housing.

It is particularly preferred here that the union nut has a through opening which widens conically towards the mouthpiece. On the one hand, this leaves only a small gap between the union nut and mouthpiece, so that the penetration of dirt is made more difficult. Such dirt could impair the mobility of the mouthpiece in the housing. On the other hand, the conical widening allows the mouthpiece to move freely without the union nut having to be arranged excessively far outside. Especially in connection with the spherical disc shape of the mouthpiece, there are advantages here, namely because the spherical disc with corresponding curves can pass relatively freely on the inside of the union nut.

Fig. 1

einen schematischen Querschnitt durch einen Teil eines Blindnietsetzgeräts,

Fig. 2

einen Teil des Gehäuses des Blindnietsetzgeräts im Schnitt,

Fig. 3

eine Draufsicht auf das Gehäuse von links in Fig. 2,

Fig. 4

eine Vorderansicht eines Mundstücks und

Fig. 5

eine Seitenansicht einer anderen Ausgestaltung eines Mundstücks.

The invention is described below on the basis of preferred exemplary embodiments in conjunction with the drawing. Show here:

Fig. 1

2 shows a schematic cross section through part of a blind rivet setting device,

Fig. 2

part of the housing of the blind rivet setting tool in section,

Fig. 3

a plan view of the housing from the left in Fig. 2,

Fig. 4

a front view of a mouthpiece and

Fig. 5

a side view of another embodiment of a mouthpiece.

A blind rivet setting device 1 has a pulling mechanism 3 movable in a housing 2 with chuck jaws 4, pressure piece 5 and a return spring 6. The pull mechanism 3 can be moved from the standby position shown to the right by a drive, not shown, which can be moved manually or by motor. Here, the chuck jaws 4 approach each other. A rivet mandrel, not shown, which has been inserted into the setting tool 1, is then grasped and likewise pulled to the right. The structure of such a pulling mechanism and the mode of operation of a blind rivet are in principle well known. It will only be dealt with in the following if this is necessary.

At the front end of the housing 2, which points to the left in FIG. 1, a mouthpiece 7 is arranged, which has a plurality of mandrel guide channels 8. The mouthpiece 7 is shown in FIG. 4 in a front view. The mouthpiece is formed by a spherical disk 11 with a diameter D. The spherical disk extends essentially symmetrically on both sides of its central plane 9. The mandrel guide channels 8 are arranged in this central plane. Bearing journals 10 are arranged on both sides of the mouthpiece 7. With these journals 10, the mouthpiece is in bearings 12 in the housing 2 stored and in such a way that it can be rotated about an axis which extends substantially perpendicular to the pulling direction of the pulling mechanism 3. The bearings 12 support the mouthpiece 7 simultaneously in the direction of movement of the pull mechanism 3.

The spherical disk 11 is provided with a number of flats 13 on its circumference. Since each flat flattening of a ball forms a circular surface, a series of circular flattenings are formed on the circumferential surface of the spherical disk 11 and thus on the circumference of the mouthpiece 7, which have a diameter a. This diameter a corresponds essentially to the width b of the spherical disk 11. The individual circular surfaces which are formed by the flattened portions 13 therefore abut one another in the central plane 9 of the mouthpiece 7. The mouthpiece 7 then has the shape of a polygon in cross section in the area of its central plane 9, as can be seen from FIG. 1. This polygon is regular, i.e. its sides 14 all have the same length a. The polygon has an odd number of sides 14 and corners 15. The term corners 15 is only to be understood here as a connection between two sides 14. The corners 15 can also be formed by a transition between two sides 14, which is rounded or has the shape of a polygon.

The mandrel guide channels 8 are now designed as through-channels, for example as bores, through the mouthpiece 7, namely, they extend from one side 14 to the opposite corner 15 Flattening 13 is formed. The rivet head can rest against this flat surface when setting.

The corner 15 protrudes into a recess 16 in a housing part 17. The recess 16 is used to pass a rivet mandrel to the chuck jaws 4. It widens towards the front end approximately V-shaped so that the sides 14 of the mouthpiece 7 can rest on the housing part 17. The housing part 17 is arranged in a sliding part 18 which is axially, i.e. in Fig. 1 from left to right and vice versa, is displaceable. To increase the friction between the housing 2 and the sliding part 18, a round ring 19 is provided, for example made of rubber, which ensures a frictional connection between the sliding part 18 and the housing 2. The sliding part 18 can therefore only be moved against a certain resistance in relation to the housing 2. Furthermore, a fastening ring 20 is provided which holds the housing part 17 in the sliding part 18. An opening 21 is provided in the housing 2, through which the housing part 17 projects.

The housing part 17 has a projection 22 pointing towards the pulling mechanism 3, which is bevelled towards the outside and serves as an opening mechanism for the chuck jaws 4. The chuck jaws 4 are pressed against the projection 22 by the force of the return spring 6. As a result, the housing part 17 is pressed against the mouthpiece 7 in the ready position shown in FIG. 1. The mouthpiece 7 is therefore fixed in the set position.

In order to prevent the mouthpiece 7 from being pushed out of the housing 2, a union nut 23 is provided which has an opening 24 through which the mouthpiece 7 projects. The opening 24 widens conically inwards. Thus, there is only a narrow gap 25 between the union nut 23 and the mouthpiece 7. The shape of the mouthpiece 7, which has arisen from the spherical disk 11, allows the conical shape Keep the opening 24 of the gap 25 small without the rotatability of the mouthpiece 7 in the housing 2 being impaired. The union nut acts on the bearing journal 10 of the mouthpiece 7.

To turn the mouthpiece 7, the pulling mechanism 3 is actuated. As a result, it moves to the right over a certain distance. It is not necessary that it be moved to its end position. It is sufficient if the chuck jaws 4 release the projection 22 to such an extent that the housing part 17 is displaced to the right by the sliding part 18 so that the mouthpiece 7 comes free from the recess 16. In this case it is no longer fixed. It can therefore be freely rotated in the bearings 12. As soon as the mandrel guide channel 8 with the desired diameter appears on the front side, the pulling mechanism 3 is moved to the left again. Here, the chuck jaws 4 press the housing part 17 back into contact with the mouthpiece 7, so that the mouthpiece is fixed.

If a rivet is now set, the pull mechanism 3 also moves to the right, as a result of which the pressing force on the housing part 17 decreases and is later released. In this case, however, the rivet mandrel is guided through the mandrel guide channel 8 and the recess 16 into the chuck jaws 4, so that the mouthpiece 7 is fixed by the rivet mandrel itself.

To adjust the mouthpiece 7, it is therefore not necessary to loosen the union nut 23.

The formation of the mouthpiece 7 as a pentagon is sufficient for most applications. On the one hand, there are enough different diameters of the mandrel guide channels 8 available, namely five. On the other hand the mouthpiece is still stable enough to be able to absorb larger tractive forces.

5 shows a further embodiment of a mouthpiece 7 '. The only difference here is the shape of the bearing journal 10 '. In cross section, this also has the shape of a polygon, which is mathematically similar to the polygon of the mouthpiece 7, i.e. the number of corners, the angles and the aspect ratios are the same. The polygon of the pin 10 'is rotated by an angle α relative to the polygon of the mouthpiece 7'. It can also be said that the polygon of the pin 10 'is mirrored about a plane 26 running through the axis of rotation and parallel to one side 14. This ensures that always one side c of the polygon of the mouthpiece 7 'and one side d of the polygon of the journal 10 are parallel to each other. With this side d, the bearing journal 10 'can be supported on a bearing surface 12' which is shown in broken lines in FIG. 2. The security against twisting is achieved here in that the mouthpiece 7 'with its journal 10' must first be lifted a certain distance from the bearing surface 12 'so that it can be twisted. This requires loosening the union nut 23. The housing part 17 can be fixed in the housing, so it can also be formed in one piece with the housing 2.

Claims (15)

Blind fastener setting device with a pulling mechanism and an adjustably mounted mouthpiece, which has a plurality of mandrel guide channels, one of which can be aligned with respect to the pulling mechanism, characterized in that the mouthpiece (7, 7 ') has the shape of an odd-numbered polygon in section, the mandrel guide channels (8) run from one side (14) to the opposite corner (15). Apparatus according to claim 1, characterized in that the polygon is designed as a regular polygon. Apparatus according to claim 1 or 2, characterized in that the mouthpiece (7, 7 ') can be rotated about an essentially stationary axis which is perpendicular to the direction of pull of the pulling mechanism (3). Device according to one of claims 1 to 3, characterized in that the mouthpiece (7, 7 ') has bearing pins (10, 10') projecting perpendicularly to the mandrel guide channels (8) with which it is attached to a bearing part (12, 12 '). the housing (2) is supported, in contrast to which the pulling mechanism (3) is movable. Apparatus according to claim 4, characterized in that at least one of the bearing journals (10 ') has the shape of the polygon with reduced sides (d), the polygon of the journal (10') being opposite to the polygon of the mouthpiece (7 ') an angle (α) is rotated, which is 180 ° divided by the number of sides (14) of the polygon, and the pin (10 ') abuts a surface (12') which extends substantially perpendicular to the direction of pull. Device according to one of claims 1 to 5, characterized in that the mouthpiece (7) in the ready state projects with a corner (15) of the polygon into a recess (16) in a housing part (17) and at least with a part of the corner ( 15) enclosing sides (14) on the housing part (17). Device according to claim 6, characterized in that the housing part (17) is movable relative to the housing (2). Apparatus according to claim 7, characterized in that means (19) are provided which bring about an increased frictional connection between the housing part (17, 18) and the housing (2). Apparatus according to claim 7 or 8, characterized in that the housing part (17) is acted upon by a restoring force in the ready state. Apparatus according to claim 9, characterized in that the restoring force acts on the housing part via the pulling mechanism (3). Device according to one of claims 6 to 10, characterized in that the housing part (17) is designed as a jaw opening device (22) for the pulling mechanism (3). Device according to one of claims 1 to 11, characterized in that the mouthpiece (7, 7 ') is formed by a spherical disk (11) which is essentially symmetrical on both sides of the mandrel guide channels (8) and which has a circumference in the region of a mouth of each Mandrel guide channel (8) has a substantially flat flat (13). Apparatus according to claim 12, characterized in that the width (b) of the spherical disc (11) essentially corresponds to the length (a) of one side (14) of the polygon. Device according to one of claims 1 to 13, characterized in that a union nut (23) is provided which holds the mouthpiece (7, 7 ') in the housing. Apparatus according to claim 14, characterized in that the union nut (23) has a through opening (24) which widens conically towards the mouthpiece (7, 7 ').

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