EP1132160B1 - Hydropneumatic blind riveter - Google Patents

Abstract

Pneumatic, hydraulic blind riveting device comprises a tension device arranged in a housing and having a cullet which is connected to a hydraulic thrust piston (14) and surrounds chuck jaws on which a pressure bushing arrangement (30, 31) interacting with a resetting piston lies (34). A pressure space (44) arranged between the resetting piston and the thrust piston is loaded by a pressure controlled by a control device (4). Preferred Features: The pressure bushing arrangement is rigid in the pressure direction between the resetting piston and the chuck jaws.

Description

The invention relates to a pneumatic-hydraulic Blind riveting tool with a pulling device, which in one Housing is arranged and has a casing, which is connected to a hydraulic traction piston and Surrounds chuck jaws on which a pressure bushing arrangement is present, which interacts with a reset piston.

Such a blind riveting device is from DE 31 53 057 C2 known. The one required to set a blind riveting tool Energy is generated using compressed air, which in many manufacturing plants with a standard pressure of 6 bar is available. This compressed air actuates you Pneumatic piston. This pneumatic piston is rigid connected to a hydraulic piston which is essential has a smaller effective area. The hydraulic piston therefore creates a relatively high pressure in a hydraulic fluid. This hydraulic fluid works then on the traction piston. The pull piston is in one tensile force-transmitting connection with the chuck housing. The lining casing has a conical inside running contact surface to the chuck jaws, in a standby position of the blind riveting tool rest on a mouthpiece and thus in the chuck housing be pushed in so that they open and a rivet mandrel of a blind rivet are used can. During the movement caused by the pulling piston The feed casing has two effects. To the the feed jaws are pressed radially inwards, if the chuck housing moves in the pulling direction the jaws moved away. When the chuck jaws then hold the mandrel in place, causing another pulling motion of the chuck that the chuck the "Take" the rivet mandrel so that the rivet mandrel takes the hollow rivet first deformed in a manner known per se and then is torn down.

After tearing off, the pneumatic cylinder is relieved, so that the hydraulic pressure on the traction piston degrades. The reset piston now acts Pressure, for example caused by the compressed air. The return piston then pushes the pull piston and thus also the chuck housing back to the starting position back. The pressure bushing arrangement has in the middle of a compression spring so that the Reset piston the chuck housing even one more can push a small distance if the forage bakken rest on a mouthpiece of the housing. Thereby the chuck jaws come free from the chuck housing and can open. The ripped mandrel can then removed or to the rear from the blind riveting tool be sucked out. A new blind rivet can be used its mandrel. Ultimately it will the spring is biased when opening the chuck jaws the next time the blind rivet is set for the Closing force of the chuck jaws on the mandrel responsible is.

Such a design of a blind riveting tool has basically proven itself. However, after Observe the setting of a certain number of blind rivets, that the chuck jaws are no longer with the desired one Keep reliability on the mandrel. It is coming increasingly for slipping through the chuck jaws on the mandrel, so that the formation of the with the Blind rivets are no longer intended for rivet connections the desired reliability. This hits in increased when the teeth of the feed jaws are already slightly dull due to wear. Thereby gripping the rivet mandrel is no longer possible or at least very difficult, which leads to the failure of the device can lead. The chuck jaws must then be replaced.

The invention has for its object a riveting process can be reliably controlled with blind rivets.

This task is the beginning of a blind riveting tool mentioned type in that between the Return piston and the traction piston arranged a pressure chamber is the one with a control device controlled pressure can be applied.

With such a configuration, one is able to the closing forces that act on the chuck jaws are more targeted to influence. Most of all, it is possible with With the help of the controlled pressure both an opening of the Cause chuck jaws when resetting the pulling device, as well as applying a closing force that in any case, generally well above the closing force of one Spring goes out. If you take the pressure room under Puts pressure, then he pushes the traction piston and with it also the chuck housing in the foremost position, in that the chuck jaws come free from the chuck housing. The Feed jaws because they rest on the mouthpiece, not be pushed further forward. But if you lowers the pressure in the pressure chamber and at the same time or later apply hydraulic pressure to the traction piston, then the chuck casing with a force opposite the chuck jaws to the "back", ie from Mouthpiece moved, which is as big as the force, which holds the reset piston in the reset position. This means that considerably greater forces are exerted on the chuck jaws transferred, resulting in a safe grasp of the Rivet mandrels with a significant increase in tool life the gripping jaw guides. First of all Wear on the gripper jaws kept to a minimum. simultaneously can be ensured over a much longer period of time be that the setting process of the rivet with the desired reliability expires.

The pressure bushing arrangement is preferably in the pressure direction between return piston and chuck jaws rigidly trained. So it is no longer a compression spring arranged between the return piston and the chuck jaws, but the reset piston can permanently from press against the chuck jaws at the back. So that's the Pressure with which the return piston over the pressure bush arrangement presses on the chuck jaws, a measure of the closing force with which the chuck housing the chuck jaws can squeeze. So far from one The compression force applied is therefore replaced by a closing force controlled by pressures.

The pressure bushing arrangement preferably has an in Split longitudinally on the pressure sleeve, the feed jaws facing end as a hollow cylinder with a smooth Shell surface is formed. So this part is a Wear part that can be easily replaced if necessary can be. When closing the chuck jaws results itself at the point of contact between the pressure bush and Cheeks always make a small movement with an appropriate one Abrasion as this movement under a partial quite high pressure. If you do that End facing the chuck jaws as a wearing part, then you do not have the entire pressure bushing arrangement Replace.

The control device preferably lowers the pressure in the Pressure chamber when they pull the piston in the direction of pull hydraulic pressure. Changing the both pressures can be simultaneous or at least in narrower temporal neighborhood. This makes it possible control of the two pressures with a single one Movement of the operator's hand or finger to effect. If the pressure in the pressure room is lowered, then the movement of the traction piston no more immediate opposition, so that the movement of the traction piston is implemented immediately can be followed by a closing movement Pulling movement.

Preferably on both sides of the return piston the same pressure adjustable, the return piston on its side facing away from the traction piston larger effective area than on its facing the pulling piston Side. Setting the same Pressures is a relatively simple measure. requires becomes just a single pressure source. By dividing up of the effective areas in different sizes on the Front (facing the traction piston) and the back of the return piston can now be just as easy apply different forces to the return piston. These forces are directed so that the return piston always loaded towards the mouthpiece becomes. When the chuck jaws touch the mouthpiece, then only the difference between the two forces is effective on the mouthpiece so that you can see the formation of the housing does not have to be excessively large.

It is particularly preferred that the return piston is connected to a return pipe, which in a Connection tube protrudes. With the help of the pull piston tube it is easily possible to change the size of the Reduce effective area.

The side facing away from the pulling piston is preferably of the return piston with a constant pressure. This pressure can be pressure act with which the blind riveter is operated, for example 6 bar compressed air. Because the pulling piston side of the return piston no longer pressure-controlled training is very easy. This pressure on the back of the reset piston must even be able to pull the towing device back in to push back their starting position.

The return piston is preferably on an ejection tube guided. This training has several advantages. On the one hand you can on the side facing away from the traction piston Form a pressure chamber on the side of the reset piston is closed to the outside, and at the same time one Provide a disposal path for torn rivet mandrels. On the other hand, an additional tour of the return piston ensures that lateral movements of the return piston almost impossible are, so that the sealing problem is reduced here becomes. The reset piston is possible with simple measures to seal towards the housing.

It is particularly preferred that the discharge tube a lock which can be actuated by a mandrel collecting container has, the locking surface so to the cross section of the Ejection tube is adapted so that a gap remains, that allows an effective outflow of air, one Ejection of blind rivet mandrels blocks. This lock is a security measure. In many blind riveters the torn rivets are sucked off or blown out with compressed air and in one Collection container collected. The collection container collects not just the rivet mandrels for a certain period of time. It also prevents operators from getting riveted be endangered in the truest sense of the word shot out of the pull mechanism during suction become. You can now prevent the mandrels are shot out of the discharge tube to the rear, by simply closing the discharge tube. In In this case, however, pressure builds up here ultimately causes the mandrels to move forward, i.e. through the mouthpiece. If the barrier is now designed so that the air flows out can, the gap between the lock and the discharge tube is so small that a rivet mandrel no longer fits then both options are excluded. The mandrel then remains in the discharge tube as long as the Lock is retracted. Such a situation occurs for example, when the operator collects the container has decreased to empty it.

It is particularly preferred that the lock through a finger is formed on a plate which is around a Axis is pivotable, which is parallel to the axis of the Ejection pipe runs. This is a considerable length saved. The lock requires practically no one Space in the axial or pull direction, but can by reliably close the discharge tube.

This is especially true when the finger is essentially is radially insertable into the discharge tube. In This case also comes in handy for moving the lock no additional installation space required.

The chuck jaws in the chuck housing are preferably in Grooves guided, the bottom of the groove over a predetermined Length has constant cross section, wherein the chuck jaws are adapted to this cross-section. In this case, the chuck jaws are in the chuck housing always held over a defined contact surface and regardless of their axial position, i.e. the situation along the direction of pull, in the casing. Leave with it the surface pressure on the chuck jaws is independent keep the position of the chuck jaws the same. Inadmissible high pressures are avoided.

Fig. 1

eine schematische Schnittansicht durch ein Blindnietgerät,

Fig. 2

eine vergrößerte Darstellung eines Teils des Blindnietgeräts,

Fig. 3

eine schematische Darstellung einer Sperre in geschlossenem Zustand und

Fig. 4

eine schematische Darstellung der Sperre in geöffnetem Zustand.

The invention is described below with reference to a preferred embodiment in connection with the drawing. Show here:

Fig. 1

1 shows a schematic sectional view through a blind riveting device,

Fig. 2

an enlarged view of part of the blind riveting tool,

Fig. 3

a schematic representation of a lock in the closed state and

Fig. 4

a schematic representation of the lock in the open state.

Fig. 1 shows a pneumatic-hydraulic blind riveting device 1 with a compressed air connection 2, above which Blind riveting tool 1 compressed air with a pressure of, for example 6 bar is supplied. A known one Slider valve 3 controls the supply of compressed air individual components of the blind riveting tool 1 under the action of a push button or push switch 4, which in a grip area 5 on the handle 6 of the blind riveting tool 1 is arranged so that it is, for example, from the index finger of an operator can be operated.

The basic functioning of such Blind riveting equipment is known. if the pressure switch 4 is pushed in, the slide valve 3 is controlled so that the compressed air below a pneumatic piston 7 comes and this up (based on the illustration 1) shifts. With the pneumatic piston 7 is a hydraulic piston 9 via a piston rod 8 rigidly connected to the movement of the pneumatic piston 7 is also moved up and hydraulic fluid in a hydraulic cylinder 10 under pressure sets and this via a channel 11 in a work room 12 promotes. The work space 12 is via a plug 13 can be filled with hydraulic fluid. The work space 12 is, among other things, of a movable one Traction piston 14 limited by the by the Channel 11 inflowing hydraulic fluid under pressure is set and thus moved. If the pressure switch 4 released and thus into that shown in FIG. 1 Position is moved, then the slide valve controls 3 µm and relieves the area below the pneumatic piston 7, so that the pulling piston 14 moves back again can and the hydraulic fluid in the Hydraulic cylinder 10 displaced.

The air is passed through a tube in a known manner 15 displaced into the space above the pneumatic piston 7 and later stands for blowing out or sucking out a torn rivet mandrel available.

The compressed air from port 2 is also in a housing room 16 permanently on and arrives from there via one Channel 17 in a recovery room 18. There is a constant pressure that corresponds to the supply pressure of the Blind riveting tool 1 corresponds.

Fig. 2 shows the head in a somewhat enlarged representation 19 of the blind riveting tool. This head 19 has a housing 20, in which a front part 21 with a mouthpiece 22 is screwed in. The mouthpiece 22 has an opening 23 through which a rivet mandrel in a known manner a blind rivet not shown introduced can be. The mouthpiece 22 protrudes with a cone-like Projection 24 somewhat in the housing 20 or its Front part 21 into it.

A pulling device is now arranged in the housing 20, starting from the pulling piston 14 a connecting pipe 25 has. On the connecting pipe 25 is a casing 26 screwed on at the front end, in the chuck jaws 27 are arranged.

The chuck housing 26 has one for each chuck jaw 27 Groove 28 in which the jaw 27 parallel to Pulling direction, which is represented by an arrow 29, can be moved. The bottom of the groove 28 is essentially semicircular. The back of the chuck jaw 27 has a corresponding semicircular rounding on. Otherwise, the walls of the groove 28 run parallel to radial jets so that the chuck jaw 27 in its Groove 28 is always guided, but at the same time independently from their position parallel to the direction of pull 29 always rests on the chuck housing 26 with the same contact surface.

The chuck jaws 27 are in through a pressure bush Direction pressed on the mouthpiece 22, the Pressure bushing a front part 30 and a rear part 31 has that abut each other. Front part 30 and The rear part 31 can be lifted off one another. If, however, against the direction of pull 29 on the Presses rear part 31, then the front part 30 against the chuck jaws 27 pressed. The front part 30 is as simple pipe section, i.e. it is as Hollow cylinder formed. It has a conical front 32 through which the chuck jaws 27 something can be spread apart when the chuck housing allows such a spreading movement. The chuck jaws 27 are bevelled accordingly opposite.

The rear part 31 projects into an ejection tube 33 and is guided there telescopically.

A reset piston 34 is sealed in the housing 20 guided. The return piston 34 forms a movable one Limit for the recovery room 18. It is determined by the pressure in the Reset room 18 acted upon.

The reset piston 34 is via a reset tube 35 connected to the rear part 31, it being sufficient if this connection can transmit pressure forces. For this purpose, the rear part 31 has a circumferential projection 36 on which a diameter reduction 37 of the return pipe 35 abuts. Of course you can the reset tube 35 but also with the rear part 31 the pressure bushing must be screwed. The connecting pipe 25 is received in a bearing tube 38, with between the connecting pipe 25 and the bearing pipe 38 gap-shaped channel 39 remains through which a channel 40 connected to an opening 41 in the connecting tube 25 is. The opening 41 in turn opens into an annular space 42 between the return pipe 35 and the connecting pipe 25. This annular space 42 is forward through the return pipe 35 sealed, this one after has outer circumferential projection 43. To the rear This annular space 42 opens into a pressure space 44 which limited by the pull piston 14 and the return piston 34 is.

The blind riveting tool 1 now works as follows:

In the rest or standby position shown in Fig. 2 the pressure switch 4 is not actuated and so that a valve 45 controlled by him is closed. in the Reservoir 18 is the pressure of the supply Compressed air, for example 6 bar. The same pressure comes up via the slide valve 3 and a channel 56, the Channel 40, channel 39, opening 41 and the annulus 42 in the pressure chamber 44. The working space 12 is not loaded. The effective pressure area of the return piston 34, which delimits the pressure space 44, is smaller than the effective area that defines the reset space 18. This results from the fact that the reset tube 35 has a larger diameter than the ejection tube 33 having. Accordingly, the reset piston is at same pressures biased towards the mouthpiece 22 and presses the chuck jaws 27 against the mouthpiece 22, more precisely its projection 24. Die Force that acts on the chuck jaws 27 results derive from the difference in force between the two Reset piston sides 34.

The pressure in the pressure chamber 44 also acts on the tension piston 14 and also pushes it towards the mouthpiece 22. Since the chuck jaws 27 are not can move further, the chuck housing 26 over the chuck jaws 27 pushed out. This movement leads to the chuck housing 26 from the chuck 27 comes free and the chuck jaws 27 radially can open to the outside. In this state, can by the opening 23 easily a rivet mandrel of a blind rivet be introduced.

The surfaces of the reset piston 34 can, for example be chosen so that at an air pressure of 6 bar a force of the order of 600 N in the direction acts on the mouthpiece 22 while a force in of the order of 570 N to the opposite Direction works. The mouthpiece works accordingly only a force of 30 N.

If a blind rivet is to be set now, then after inserting the blind rivet into the mouthpiece 22 the pressure switch 4 is actuated. This now vented the Pressure space 44 via the annular space 42, the opening 41 and the channel 39 and the channel 40. Accordingly breaks the pressure in the pressure chamber 44 more or less suddenly together. At the same time, the slide valve 3 the pneumatic piston 7 pressurized so that the rapidly building up hydraulic pressure in the Working space 12 arrives and the traction piston 14 to the rear, i.e. in Fig. 2 shifts to the right.

On the return piston 34 now act on one side Pressure in the resetting space 18 and forces in the direction of the mouthpiece 22. In the described In the exemplary embodiment, these are, for example, 600 N. With this 600 N, the chuck jaws 27 in the chuck housing 26 pushed in. This force is essential higher than you can get with most springs could. So there is a very high closing force, so that the mandrel is securely gripped by the chuck jaws 27 can be. If due to the rivet mandrel no further inward movement of the chuck jaws 27 is possible, then the traction piston 14 moves over the chuck housing 26 held in the chuck jaws 27 Rivet mandrel continues to the right, forming the rivet head and the mandrel is torn off later. in this connection the traction piston 14 must against the pressure in the recovery room 18 work, using the appropriate force the chuck housing and the chuck jaws on the return piston 34 transmits. This pressure in the reset room However, 18 is comparatively small, so that he Riveting process does not significantly interfere.

When the riveting process is finished, what the operator does Tearing off the rivet mandrel hears and also feels, then lets he released the pressure switch 4. The hydraulic pressure in the Working space 12 drops because the air pressure is below the Pneumatic piston is lowered by the control valve 3 and the pneumatic piston 7 together with the hydraulic piston 9 returns to the starting position. At the same time, the pressure in the pressure chamber 44 is built up. Since the pressure in the pressure chamber 44 is as great as in the resetting space 18, the surfaces of the resetting piston 34 but differ, the pressure in the recovery room 18 the return piston 34 again in the direction Slide on the mouthpiece 22 until the Place the chuck jaws 27 on the mouthpiece 22. The pressure in Pressure chamber 44 then pushes the chuck housing 26 somewhat continue towards the mouthpiece 22 so that the Release the chuck jaws 27 and release the mandrel.

The now released rivet mandrel is removed with the help of a principally known suction through the front part 30 and the rear part 31 and the discharge tube 33 conveyed to a container 46, shown only schematically, which is attached to the rear of the head 19. This Container 46 has two functions. For one, he collects them torn rivet mandrels. On the other hand, it prevents the rivet mandrels free in the head Fly around.

To prevent that when the container 46 is removed a such danger arises, one in Figs. 3 and 4 is closer shown lock 47 provided with the discharge tube 33 cooperates. The lock has a plate 48 with a finger 49, the plate 48 by one Pivot 50 is pivotable. The pivot axis plate 48 is parallel to the axis of the ejection tube 33 directed. The ejection tube 33 has an opening 51 through which the finger 49 can be retracted. A spring 52 holds the plate 48 in that shown in FIG. 3 Position when the container 46 is not assembled is. The container 46 is via a bayonet lock connectable to the head, i.e. for its attachment a turn of about 45 ° is sufficient. At this turn the container engages a projection 53 on the Plate 48 and moves this shown in Fig. 4 Position.

In the position shown in FIG. 3, the Finger 49 the free cross section of the ejection tube 33 not completely. Rather, a gap 54 remains which is chosen so large that the to remove the Rivet mandrels used air can flow freely, so no pressure is built up in the ejection tube 33 but is so narrow that the torn rivets cannot get past the finger 49.

This lock can also be independent of that described structure of the pulling device can be used.

Claims (12)

1. Pneumatic-hydraulic blind riveter with a traction device which is arranged in a housing (20) and comprises a chuck housing (26) which is connected to a hydraulic traction piston (14) and surrounds chuck jaws (27) against which abuts a pressure bush assembly which cooperates with a return piston (34), characterised in that between the return piston (34) and the traction piston (14) is arranged a pressure chamber (44) which can be subjected to a controlled pressure via a control device (3, 4).
2. Blind riveter according to claim 1, characterised in that the pressure bush assembly (30, 31) is rigid in the direction of pressure between return piston (34) and chuck jaws (27).
3. Blind riveter according to claim 1 or 2, characterised in that the pressure bush assembly (30, 31) comprises a pressure bush which is divided in the longitudinal direction and whose end (30) facing towards the chuck jaws is designed as a hollow cylinder with a smooth peripheral surface.
4. Blind riveter according to any of claims 1 to 3, characterised in that the control device (3, 4) lowers the pressure in the pressure chamber (44) when it subjects the traction piston (14) to hydraulic pressure in the direction of traction (29).
5. Blind riveter according to any of claims 1 to 4, characterised in that the same pressure can be set on both sides of the return piston (34), wherein the return piston (34) has a larger working area on its side facing away from the traction piston (14) than on its side facing towards the traction piston (14).
6. Blind riveter according to claim 5, characterised in that the return piston is connected to a return tube (35) which extends into a connecting tube (25).
7. Blind riveter according to any of claims 1 to 6, characterised in that the side of the return piston (34) facing away from the traction piston (14) is subjected to a constant pressure.
8. Blind riveter according to any of claims 1 to 7, characterised in that the return piston (34) is guided on an ejector tube (33).
9. Blind riveter according to claim 8, characterised in that the ejector tube (33) comprises a barrier (47) which can be actuated by a mandrel collecting receptacle (46) and whose barrier surface is adapted to the cross-section of the ejector tube (33) in such a way that a gap (54) remains, which allows effective outflow of air but blocks discharge of blind rivet mandrels.
10. Blind riveter according to claim 9, characterised in that the barrier (47) is formed by a finger (49) on a plate (48) which is pivotable about a shaft (50) which runs parallel to the axis of the ejector tube (33).
11. Blind riveter according to claim 10, characterised in that the finger (49) can be introduced substantially radially into the ejector tube (33).
12. Blind riveter according to any of claims 1 to 11, characterised in that the chuck jaws (27) in the chuck housing (26) are guided in grooves (28) whose groove bottom has a constant cross-section over a predetermined length, wherein the chuck jaws (27) are adapted to this cross-section.

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