EP0062206B1 - Pneumatic-hydraulic blind rivets device - Google Patents

Abstract

A riveter has a housing forming an air chamber and a liquid-filled hydraulic chamber adjacent thereto, a head on the housing having a tip and forming a liquid-filled working chamber communicating with the hydraulic chamber, and a working piston in the working chamber and carrying a chuck for grasping a mandrel of a blind rivet. The head and chuck form a passage having a front end opening at the tip and a rear end opening into a mandrel-catching compartment and the piston displaceable in the working chamber between a ready position in which a mandrel of a blind rivet can be fitted into the passage at the chuck with the rivet engaged backwardly against the tip and an actuated position spaced from the tip and wherein the chuck is retracted. An air piston is provided in the air chamber and carries a hydraulic piston displaceable in the hydraulic chamber between an advanced position pressurizing the hydraulic and working chambers and corresponding to a front position of the air piston and a retracted position corresponding to a rear position of the air piston.

Description

The invention relates to a pneumatic-hydraulic blind riveting device for setting blind rivets consisting of a rivet sleeve and a tear-off mandrel, with a pneumatic cylinder in which a pressure piston and a plunger which is rigidly connected to it and sealed and plunges into a subsequent hydraulic chamber can be moved back and forth, and with a device head adjoining the hydraulic chamber, in which a pulling device carrying the chuck mechanism for gripping the pulling mandrel can be moved back and forth pneumatically and hydraulically, wherein a through-channel for the ejection of the pulling mandrels torn off during the riveting process is provided in the device head.

Such a blind riveting tool is e.g. B. known from DE-PS 2 419 190. The traction consists essentially of a piston which can be sealed in a cylinder space of the device head, which rests in the rest position of the device on a stop formed in the cylinder space and which has a piston shaft on each side, of which the piston located on the side of the mouthpiece of the device head Carries the feed mechanism and the other protrudes into an opening provided on the side of the device head opposite the mouthpiece and aligned with it. The passage channel for the ejection of the mandrel torn off during each riveting process passes through the piston and its two piston shafts. The cylinder space of the device head is connected to a hydraulic chamber on the side of the piston facing the mouthpiece. When the device is actuated, compressed air is applied to a pneumatic piston and moved in its pneumatic cylinder in such a way that a plunger rigidly connected to it plunges into the hydraulic chamber in a sealed manner on its outer surface. The hydraulic medium displaced thereby acts on the piston in the cylinder space of the device head, so that the chuck mechanism engaging the pulling mandrel of a blind rivet is pushed back into the device head and the pulling pin is torn off at its predetermined breaking point, forming a rivet head. During the pulling movement of the piston, its piston shaft provided on the side facing away from the mouthpiece can slide into the opening of the device head that is flush with it. When the actuating lever is released after the riveting process has ended, the compressed air preferably escapes from the pneumatic cylinder via a quick exhaust valve, and all parts can be returned to their starting position. The torn mandrel is then still in the passage channel of the pull piece formed from the piston displaceable in the device head together with its piston shafts, so that the operator of the device must first make a pivoting movement in order to eject the mandrel from the passage channel in the device head. It is already known to attach a collecting container to the device head, into which the passage channel opens in order to collect the torn mandrels therein. The necessary swiveling movement is tedious in the long run because it is an additional movement and requires additional attention; it also hinders rapid work.

A device has therefore already been proposed in which, behind the clamping jaws of the chuck mechanism, an air duct connected to a compressed air source opens into the passageway of the blind riveting device in such a way that a compressive force is exerted on the mandrel lying in the passageway, which compresses the torn mandrel into one at the end of the passage channel arranged container transported. This known device has the disadvantage that the compressed air supply takes place in the area of the feed mechanism, which requires special training of the feed mechanism and the actuating device for the feed mechanism. Furthermore, the air connection must participate in the axial movement of the chuck mechanism during the riveting process, so that a particularly robust design of the feed line is necessary. Another disadvantage of the known device is that the effect of the compressed air introduced into the passage channel is also directed against the newly inserted mandrel for the next riveting process, so that it can be pushed out of the chuck mechanism again.

These disadvantages could be eliminated with a device according to DE-OS 2 827 904, which is designed as an additional device for pneumatically operated blind riveting devices and consists of a collecting container which can be attached tightly to the device head of the blind riveting device and which, preferably in its removable cover, has a vacuum system operated by compressed air contains, which can be connected via a connecting line to a compressed air source, which is preferably also that of the blind riveting tool. When the device is used, a vacuum is generated in this container by the vacuum system contained in the collecting container, which then pulls the torn mandrel out of the chuck mechanism through the passage channel in the device head and hurls it into the collecting container. With this additional device, practically any (pneumatically) operated blind riveting tool can be retrofitted in a simple manner by only placing the container containing the vacuum system tightly on the device head and a connecting line between the connection of the vacuum system and the compressed air source, that is to say preferably the part of the connecting nipple which carries compressed air of the blind riveting tool is connected. However, just like the previously briefly described device, this additional device also consumes additional energy because compressed air must not only be provided for the actual riveting process, but also for the ejection or suction of the torn mandrel, and the production and supply of compressed air is known expensive. To the negative pressure in the collecting container during operation the vacuum system must be constantly supplied with compressed air; this creates a u. U. constant noise disturbance for the operating porson as well as a disturbing lie of the air. In addition, the connection line between the vacuum system in the Aultang container and the compressed air connection, which must always be installed on the outside of the device when retrofitting a blind riveting device, can be a hindrance.

The continuous operation of the vacuum system can result in the advantage that a blind rivet inserted into the mouthpiece is held in the mouthpiece by the negative pressure generated in the device head before its mandrel is gripped by the chuck mechanism. However, this small advantage is generally not related to the high energy consumption and the annoyance caused by the constantly generated compressed air. In certain ways of working, it can even turn into a disadvantage; if the blind rivets are inserted into the material to be riveted, the rivet can be pulled out of the rivet hole when the blind riveting tool approaches due to the continuous operation of the vacuum system.

The object of the invention is, while avoiding the disadvantages described, to integrate a device for ejecting or extracting the mandrel torn off during the riveting process into the blind riveting device. The suction or blowing out of the mandrel should take place automatically after each riveting process, but as energy-saving as possible. In particular, the compressed air required for the riveting process should also be able to be used for suctioning off the rivet mandrels torn off during the riveting process. The device should also be designed for certain applications so that it can keep the rivet ready in the mouthpiece even before the riveting process with a constant metered supply of compressed air. In all of this, the entire blind riveting device should be compact in terms of its outer dimensions and relatively small, and light in weight, yet powerful, and in particular be able to process all commercially available rivets with rivet diameters of up to 1/4 inch.

This object is achieved according to the invention in that the compressed air introduced to carry out a riveting process in the pneumatic chamber located behind the pressure piston after the riveting process has been carried out can be introduced into the passage channel in the ejection direction via bores provided in the blind riveting device.

The compressed air can preferably be introduced into the passage channel through a nozzle located behind the mandrel in the ejection direction.

The suction device for the torn off mandrels is thus integrated into the actual blind riveting device, and the compressed air that is necessarily required to carry out the riveting process is advantageously used twice, namely for the riveting process and for suctioning the mandrel. The suction process is carried out automatically after the riveting process, but saves energy because compressed air does not have to be supplied separately for suction. The intermittent operation of the compressed air for riveting and suctioning the mandrel also saves energy compared to continuous operation according to the prior art; the noise and train annoyance of the operator is greatly reduced. By integrating the suction device into the actual blind riveting device, there are also no annoying supply lines on the outside of the device.

The compressed air emerging from the nozzle at high speed creates a suction in the through-channel, which, as soon as it is released by the chuck mechanism, sucks the mandrel and transports it back out of the through-channel. Preferably, a nozzle tube is arranged concentrically in the passage channel to the inner wall of the passage channel, the end facing away from the chuck mechanism is widened radially in the direction of the wall of the passage channel and thus forms the nozzle, wherein the compressed air through a bore in the wall of the passage channel into the Gap between the inner wall of the passage and the nozzle tube can be introduced.

In a preferred embodiment of the invention, the passage channel is formed by a hollow cylindrical pulling element arranged coaxially in the device head, which carries the chuck mechanism at one end and a pulling piston which can be displaced tightly in the device head at its other end, and in from the side of the pulling piston the tension piece inserted pressure tube that pierces the end cover of the device head.

The nozzle tube can rest with one end sealingly on a pressure bush arranged inside the tension piece, resting on the chuck jaws of the chuck mechanism and with its widened end forming the nozzle, it can protrude into the pressure tube, a compression spring surrounding the nozzle tube between the pressure bushing and the pressure tube is arranged. Thus, the suction device can be set up in an advantageous manner using components already present in the blind riveting device and inserting only relatively few additional components and thus in a space-saving and cost-effective manner in the blind riveting device. The construction of the blind riveting device remains compact despite the additionally integrated device and is nevertheless powerful.

A further piston (return piston) is preferably assigned to the pull piston, by means of which the compression spring can be relieved. This avoids a lifting movement of the traction piston when the riveting tool is depressurized, which could lead to a vacuum or to air ingress in the hydraulic chamber.

The tension piece can advantageously be surrounded by a cylinder sleeve below the tension piston at its end facing the traction piston has a radially inward shoulder against which the traction element can be moved tightly and, moreover, leaves an annular space for the traction element, into which the housing bore for supplying the compressed air opens; In addition, in the area of the bore in the traction piece for passing on the compressed air to the nozzle, the traction piece of one

Ring piston be surrounded, which is located in the starting position of the pull piece outside the cylinder sleeve and creates a connection between the space surrounding it and the bore in the pull piece and in the retracted state of the pull piece is inside the cylinder sleeve and seals the bore against the surrounding space abuts the wall of the cylinder sleeve.

Thus, the compressed air introduced to carry out the riveting process and, after completion of the riveting process, redirected by reversing a valve into the aforementioned housing bores, is initially briefly stored and only admitted into the nozzle according to the invention when the pulling device and with it the chuck mechanism still holding the torn off pulling mandrel have almost returned to their starting position, so that the suction effect of the compressed air emerging from the nozzle only comes into effect when the torn mandrel is released by the chuck mechanism.

Preferably, the housing bore guiding the compressed air for the suction process opens via a puncture in the cylinder sleeve into the annular space formed in the retracted state of the pull piece between the shoulder of the cylinder sleeve lying close to it and the annular piston. As a result, the reversed compressed air is initially also stored in this annular space, and the compressed air thus acting on the annular piston advantageously supports the return of the pulling device and the chuck mechanism to its starting position before the compressed air is passed on to the nozzle in the passage channel.

The passage channel preferably opens into a collecting container which is mounted on the device head and has a connection to the atmosphere; the torn-off and extracted mandrels can be collected in a collecting container in a known manner.

However, the blind riveting device should not only allow the torn rivet mandrel to be sucked backwards into the collecting container provided at the end opposite the mouthpiece of the device head, but also to allow the torn rivet mandrel to be ejected forward through the mouthpiece. Therefore, in a further embodiment of the invention, after unscrewing a sleeve containing the mouthpiece and the chuck mechanism and screwable to the device head, the nozzle tube can be removed through the pulling element, and the blind riveting device can thus be operated without the nozzle tube with a mandrel ejection through the mouthpiece.

A collecting container, into which the passage channel opens, can be firmly connected to the device head.

The collecting container preferably consists of a cup with a suitably shaped sleeve pushed over it, both of which have at least one window-like opening in their wall, which can be closed or covered by rotating the sleeve against the cup, so that the collecting container is emptied in a convenient manner can be.

The collecting container has air outlet openings in its base. The collecting container is preferably made of plastic; its base can be cut out in a circle, and a baffle plate with passage openings is then held by the remaining base ring.

An adjustable pressure relief valve can be arranged in the pneumatic connection between the compressed air connection and the passage channel.

By simply turning an adjusting screw of the pressure relief valve, a metered constant supply of compressed air can then be effected into the passage channel, so that a negative pressure is generated which holds a blind rivet inserted into the mouthpiece in place.

In order to ensure a correct return of the blind riveting device to its starting or standby position, the area sizes of the ring areas above and below the pressure piston are preferably approximated to one another to approximately the same values. Advantageously, the approximation of the surface area of the ring surfaces above and below the pressure piston is achieved by means of a compensating piston which, on the one hand, is fastened to the cylinder pot base and, on the other hand, can protrude coaxially with the latter into the plunger piston into the region of the flange of the handle facing away from the device head.

• Fig. 1a und 1 b zeigen gemeinsam einen Längsschnitt durch das erfindungsgemäße Blindnietgerät in Ausgangs- bzw. Bereitschaftsstellung, wobei die linke Seite der Fig. 1b unmittelbar rechts an die Fig. 1 anschließend zu denken ist.
• Fig. 2a und 2b zeigen gemeinsam einen Längsschnitt durch das Blindnietgerät gemäß Fig. 1 und 1 b in der hinteren Endlage nach vollzogenem Nietvorgang, aber kurz vor Rücklauf in die Ausgangsstellung und Auswurf des abgerissenen Zugdorns, wobei auch hier die linke Seite der Fig. 2b unmittelbar rechts an die Fig. 2a anschließt.
• Fig. 3a zeigt in schematischer Darstellung den Rücklauf des unbetätigten Blindnietgeräts in seine Ausgangs- bzw. Bereitschaftsstellung.
• Fig. 3b zeigt in schematischer Darstellung den Vorlauf (Arbeitshub) des betätigten Blindnietgeräts.

Further details and advantages of the invention result from the following description of a preferred embodiment of the invention with reference to the attached drawing.

• 1a and 1b together show a longitudinal section through the blind riveting device according to the invention in the starting or standby position, the left-hand side of FIG. 1b being immediately to the right of FIG. 1.
• 2a and 2b together show a longitudinal section through the blind riveting device according to FIGS. 1 and 1b in the rear end position after the riveting process has been completed, but shortly before returning to the starting position and ejecting the torn mandrel, the left side of FIG. 2b also here immediately to the right of Fig. 2a.
• 3a shows a schematic representation of the return of the unactuated blind riveting device to its starting or standby position.
• 3b shows a schematic representation of the advance (working stroke) of the actuated blind riveting device.

According to FIGS. 1a and b as well as FIGS. 2a and b, the pneumatic-hydraulic blind riveting device according to the invention consists of the device head A, the handle B enclosing the hydraulic part of the drive system and the pneumatic part C of the drive system. The device head A consists of an essentially hollow cylindrical housing part 1, preferably made of hard-coated aluminum, into the front end of which a screw-in sleeve 3 carrying the mandrel receiving the mandrel of a blind rivet to be riveted is screwed with an inner diameter which is reduced to a certain extent compared to the housing part 1. The sleeve 3 is preferably made of steel; the mouthpiece 2 can advantageously be exchangeable for different rivet diameters. The steel sleeve 3 may have a hole on the side or, preferably opposite one another, two side holes which serve to promote the ejection of the torn rivet mandrel to the rear when the blind riveting tool is in contact with the blind rivet head and also to allow the chuck jaws to be oiled without disassembly. Inside the steel sleeve 3 and coaxially to it is a hollow cylindrical tension piece 4, the outer diameter of which is significantly smaller than the inner diameter of the sleeve 3 and which extends far into the housing part 1 (approximately to half its length). At its front end facing the mouthpiece 2, the tension piece 4 carries the chuck housing 5 with the chuck jaws 6 for gripping the pulling mandrel of a blind rivet to be riveted. Within the housing part 1, the pull piece 4 is guided several times tightly; So behind the connection point between the housing part 1 and the sleeve 3 is a wiping ring 7 which bears against the housing wall with its outer diameter and which has an annular groove in its inner surface which receives an O-ring 8 which lies sealingly on the tension member 4. At a distance from the scraper ring 7 there is a thin-walled cylinder sleeve 9 with its outer surface resting against the housing wall 1, the inner diameter of which is reduced at its rear end facing away from the mouthpiece 2 by a shoulder 10 to the outer diameter of the pulling member 4. In an annular groove of this paragraph 10 there is also an O-ring 11 sealingly attached to the tension piece 4. The cylindrical sleeve 9 rests with its shoulder 10 on a casing ring 12 which is fixedly arranged in the housing part 1 and which bears against the housing wall 1 with an O-ring 13 and is sealed against the tension piece 4 with a rod seal 14. At its rear end facing away from the mouthpiece 2, an annular pulling piston 15 is formed in one piece with the pulling piece 4 or is fixedly connected, preferably screwed, the outer surface of which is sealed against the housing wall 1 by means of a piston seal (groove ring) 17. In the initial or rest position of the blind riveting tool, the pulling piston 15 rests with its one annular surface on the casing ring 12. An annular piston 18 is secured behind the scraper ring 7 on the hollow cylindrical tension piece 4 with the aid of a retaining ring 19. The outer diameter of this annular piston 18 is significantly smaller than the inner diameter of the housing part 1 surrounding it, and it is approximately equal to the inner diameter of the cylinder sleeve 9. A recess 20 in the inner surface of the annular piston 18 creates an annular space 20 which surrounds the pulling element 4 and which is characterized by an or a plurality of bores 21 in the cylinder wall of the tension member 4 is connected to the interior thereof and, in addition, in the embodiment of the device (FIGS. 1a and b) is also connected to the interior of the housing part 1 surrounding the annular piston 18 through recesses not visible in the drawing. An O-ring 22 is located in a groove in the lateral surface of the annular piston 18. As will be described in more detail below, the annular piston 18 moves into the cylinder sleeve 9 during an actuation stroke of the pulling element 4, the O-ring 22 then sealing bears against the inner wall of the cylinder sleeve 9 and tightly separates the annular spaces lying inside the cylinder sleeve 9 in front of and behind the annular piston 18. Within the cylindrical cavity of the traction element 4 there is a pressure bushing 23 at the end facing the mouthpiece 2, the pressure ring bushing 23 resting with its front ring edge on the chuck jaws 6. The pressure bushing 23 is guided at least over part of its length on the side facing the mouthpiece 2 within the pulling element 4 by means of a sliding fit. On the annular surface of the pressure bush 23 facing away from the mouthpiece 2, there is a nozzle tube 24, the outer diameter of which is significantly smaller than the inner diameter of the pulling element 4, with a flange 25 formed at one end and projects with its other end into the interior of a pressure tube 26 with play , which slidably protrudes from the side facing away from the mouthpiece 2 into the pull piece 4 on its inner surface. The nozzle tube 24 protruding into the pressure tube 26 is widened at its outer end in the direction of the inner surface of the pressure tube 26 and forms a fine nozzle 27 for the passage of air at this point, as will be described in more detail below. Arranged around the nozzle tube 24 is a compression spring 28, which is supported on the one hand on a spacer ring 29 arranged behind the flange 25 of the nozzle tube 24 and on the other hand on the ring surface of the pressure tube 26 projecting into the pull piece 4, thereby sealing the flange 25 of the nozzle tube 24 presses the annular surface of the pressure bush 23. With its other end, the pressure pipe 26 protrudes through a central opening in the end cover 30 (designed as an end screw) of the housing part 1 into a collecting container 31 fastened to the housing part 1. In the end cover 30 and in the collecting container 31, the pressure pipe 26 is through a into the central opening the cover 30 inserted grommet 32 guided sealing. A sealing ring 33 between the wall of the housing part 1 and the end cover 30 ensures a tight closure of the interior of the housing to the outside.

In the construction described above, the working piston of the actuating device for the rental process and the tearing of the rivet mandrel is divided into a piston arrangement, which exists, in comparison with that in a prior art blind riveting device (working piston 5 according to DE-PS 2 419 190) from an annular return piston 34, the pull piston 15 with the pull piece 4 and the pressure tube 26. Under the pressure of the compression spring 28, the pressure tube 26 and the reset piston 34 can be moved in the direction of the end cover 30 when the blind riveting tool is not connected to the compressed air source are while the traction piston 15 remains in position with the traction element 4, ie do not perform any lifting movement. With the displacement of the pressure tube 26 and the return piston 34, the compression spring 28 relaxes at the same time, so that on the other hand it does not exert such pressure on the pressure bush 23 and further on the chuck jaws 6 that could initiate a movement of the pulling element 4 with the tension piston 15. Thus, this arrangement prevents the riveting tool 15 from moving when the rivet 15 is depressurized, with the pulling piece 4, which in turn could lead to a vacuum and air ingress into the hydraulic chamber, which would jeopardize the functional reliability of the riveting tool.

The collecting container 31 consists of a plastic cup 95 which widens slightly conically from the housing part 1 and over which an equally conically shaped plastic sleeve 96 is pushed. The cup 95 and the sleeve 96 each have at least one window-like opening 97 on their circumference. By mutually rotating the cup 95 and the sleeve 96, these openings 97 can be closed or made to coincide in order to be able to empty the collecting container 31. In the exemplary embodiment, the bottom of the plastic cup 95 is cut out in a circle, and the remaining bottom ring 98 and an undercut in the inside wall of the cup hold a baffle plate 101, preferably made of sheet steel, provided with small air outlet openings 100, against which the pulling mandrels flung into the collecting container 31 collide. The air outlet openings 100 are preferably provided on a circular line or an annular region. For safety reasons, the collecting container 31 can be firmly connected, preferably screwed, to the housing part 1. In the embodiment shown in the drawing, the plastic cup 95 has an undercut 99 at its open end or to be connected to the housing part 1, behind which an annular flange 102 of the end cover 30 engages. The cup 95 together with the sleeve 96 fits into a step 103 provided on the housing part 1. The collecting container 31 is then screwed to the housing part 1 via the end cover 30. Below the end cover 30 is against a shoulder of the outer wall of the pressure tube 26, preferably fixed there or in a recess in the same, the return piston 34, which is sealed against the housing wall 1 by a groove ring 36. Immediately below the return piston 34 there is a puncture 37 in the wall of the pressure tube 26 and at a distance therefrom an O-ring 38 inserted into an annular groove outside in the wall of the pressure tube 26. In the ready position of the riveting tool shown in FIGS. 1a and b is, as will be explained in detail below, the return piston 34 is acted upon by compressed air from its rear side and is in the advanced state in contact with the pull piston 15.

At the side of the device head A there is an essentially cylindrical extension 39 of the housing part 1 in a slightly inclined position. This extension 39 is surrounded by the handle piece B, leaving an intermediate space 40, which is expanded at both ends like a flange and by a sealing ring holder 41 from free end of the extension 39 ago with this and thus with the housing part 1 is screwed. The intermediate space 40 is sealed on the sealing ring holder 41 by sealing rings 42, 43 against the inner wall of the grip piece B and by a sealing ring 44 against the outer wall of the extension 39, the sealing ring 44 on the other hand preventing the entry of hydraulic medium from the hydraulic space 49 into the intermediate space 40 . The gap 40 widens at the joint between the handle B and the device head A on the side facing the collecting container 31 to a cavity 45, which is sealed to the outside by a flat seal 46 at the joint between the handle B and the device head A and through a bore 47 in the wall of the device head A has a connection with an annular space 48 formed by a recess between the end cover 30 and the housing wall 1 or between the end cover 30 and the return piston 34.

In the extension 39 there is a cylindrical bore in the exemplary embodiment, which forms the hydraulic chamber 49, which has a throttle check valve 50 arranged on its bottom and a bore 51 with the annular hydraulic chamber 52 between the casing ring 12 and the tension piston 15 in the housing part 1 connection . Outside the extension 39, in the drawing of the connecting hole 51 to the hydraulic chamber 49 directly opposite, a refill hole for the hydraulic chamber 52 is provided in the housing wall 1, which is sealed by a refill screw 53 and with the help of a sealing ring 54. Hydraulic medium can be refilled easily through this refill hole if the refill screw 53 has to be removed if necessary, without complicated assembly work.

The throttle check valve 50 on the bottom of the hydraulic chamber 49 consists essentially of a cylindrical valve body 55 which is sealed on its outer surface by a sealing ring 56 against the wall of the hydraulic chamber 49 and a passage opening 57 for the bore 51 in the housing wall in connection therewith Has hydraulic medium. In a cylindrical recess of the valve body 55 facing the hydraulic chamber 49, into which the passage opening 57 opens, a throttle disc 58 with a very small passage or throttle opening 59 is inserted and secured against falling out by a retaining ring 60 inserted into a groove in the cylindrical recess. When the throttle disk 58 is acted upon by hydraulic medium the hydraulic chamber 49, the throttle disc 58 closes the passage opening 57 in the valve body 55 except for the small throttle opening 59. The backflow of the hydraulic medium takes place unthrottled via a recess 61 on the circumference of the throttle disc 58.

The cylinder pot 64 of the pneumatic part C of the drive system is connected to the flange 62 of the handle B facing away from the device head A by means of eight long screws 63. The cylinder pot 64 is preferably made of several pieces and is advantageously also made of plastic. The screws 63 are arranged so that they are not visible and the screw heads are sunk into a base plate 104, which is placed against the bottom of the cylinder pot and is designed as a metal plate, and are covered by a rubber strip 65 running around the bottom of the cylinder pot. When not in use, the device can advantageously be placed upright on the bottom of the cylinder pot or the rubber stand 65. A central opening is provided in the bottom of the cylinder pot and in the bottom plate 104, which is in contact with it from the outside, in which a compensation piston 66, which is open on both sides and closes with the bottom of the cylinder pot, is tightly fastened, and through the entire cylinder pot 64 into the flange part 62 of the handle B protrudes. In the illustrated embodiment, the compensating piston 66 is screwed from the outside to the cylinder pot base and the base plate 104 by a hollow screw 105.

Arranged in the cylinder pot 64 is an annular pneumatic pressure piston 67, which is sealed on its outer circumference by means of an O-ring 68 inserted in a circumferential annular groove, and the inside diameter of which is larger than the outside diameter of the compensating piston 66.Coaxial to the compensating piston 66 and the pressure piston 67 is firmly connected to the latter, a hollow plunger 69, which projects with its closed, free end through the central opening of the sealing ring holder 41 into the hydraulic chamber 49 filled with hydraulic medium. The hydraulic chamber 49 is through a rod seal 70 between the sealing ring socket 41 and the plunger 69 against the pneumatic cylinder cup 64 and through the already mentioned sealing ring 44 between the outer wall of the housing extension 39 and the sealing ring socket 41 screwed onto this against the intermediate space 40 between the housing extension 39 and the handle B sealed. A guide ring 72 for the plunger 69 is arranged between the rod seal 70 and a radially inwardly projecting extension 71 of the sealing ring holder 41. On the side of the extension 71 facing the pneumatic cylinder 64 there is a groove ring 73 which tightly surrounds the plunger 69 and seals the pneumatic chamber 83. The wall of the compensating piston 66, which projects into the hollow plunger 69 while maintaining a radial space, is reinforced at its free end almost to the inside diameter of the plunger 69, and a sealing ring 74 placed in an annular groove of this reinforcement lies sealingly against the inner wall of the plunger 69 . The open end of the plunger 69 connected to the annular pneumatic pressure piston 67 is inserted into the central opening of the pressure piston 67. On the side of the pressure piston 67 facing away from the bottom of the cylinder pot 64 there is a stop ring or radial stop extension 75 resting on the latter and surrounding the plunger 69.

The pneumatic control for the drive of the device is accommodated in the lower part of the handle B and its flange 62 connected to the cylinder pot 64, as shown in the drawing. To explain the same reference is also made here to FIGS. 3a and 3b. In the reinforced flange part 62, a 4/2-way pneumatic valve 77, which is indicated by a dashed circular line in FIG. 1a and b as well as FIGS. 2a and b and preferably has a negative control, is accommodated transversely and consists of a control cylinder and a control slide. The input connection of the 4/2-way valve 77 is connected to a compressed air hose 82 which is attached to the outside of the flange 62 by means of a connecting sleeve and a connecting sleeve 81 and which does not show in FIGS. 1a and b and in FIGS. 2a and b, but in 3a and 3b indicated compressed air source Q leads, connected; the space 40, which is always pressurized with compressed air when the device is connected to the compressed air source, has a connection with the pneumatic line between the handle B and the surrounding housing extension 39 and from there via the bore 47 to that between the end cover 30 and the return piston 34 annular space 48 located in the device head. The two other connections of the 4/2-way valve 77 are each connected to one of the pneumatic chambers located in the cylinder head 64 in the actuating direction of the pressure piston 67 in front of or behind the latter. The fourth connection of the 4/2-way valve 77 represents a connection to the atmosphere. The pneumatic chamber 83 lying in front of the pressure piston 67 in the actuating direction of the pressure piston 67, that is to say partially closed by the flange 62 of the handle piece B, is via a bore 84 in the handle piece B. , which continues at the connection point sealed by an annular seal 85 between the handle B and the device head A as a bore 84 'in the device head A, and is connected to the annular space 87 surrounded by this cylinder sleeve 9 by a puncture 86 in the cylinder sleeve 9 arranged in the housing part 1. The puncture 86 opens directly under the shoulder 10 of the cylinder sleeve 9 into this annular space 87. The connection of the 4/2-way valve 77 to the pneumatic chamber 88 located behind the pressure piston 67, that is to say delimited by the bottom of the cylinder pot 64, is established by a channel tube 80 projecting longitudinally through the cylinder pot 64 and penetrating the pressure piston 67 r Piercing opening of the pressure piston 67 encircling annular groove receives a sealing ring 89 sealing against the outer surface of the sewer pipe, so that the pressure piston 67 is tightly guided on the sewer pipe 80 during its movement.

In the initial position of the 4/2-way valve 77, the two pneumatic chambers 83 and 88 are connected to one another, and the intermediate space 40 is connected to the compressed air connection 82. By pressing the control button 90 located on the underside of the handle B, the actuating valve 91 designed as a 2/2-way valve switches the 4/2-way valve 77 via a corresponding control line 76, and the pneumatic chambers 83 and 88 thereby become separated from one another, and the pneumatic chamber 88 located behind the pressure piston 67 is connected to the compressed air connection 82. The space 40 always remains connected to the compressed air connection 82. In addition, a pressure relief valve 92 is arranged in the flange part 62 of the handle B, which can establish a connection in front of the intermediate space 40 to the pneumatic chamber 83 located in front of the pressure piston 67 via a bore 109. The pressure relief valve 92 is adjustable from the outside by an adjusting screw 92 '; if necessary, a precisely metered permanent connection between the intermediate space 40 and the front pneumatic chamber 83 can also be established.

An approximately 2 cm wide hand guard 106 is provided below the handle B, which extends in an arched manner from the front part of the device head A to the flange part 62 of the handle B and is fastened there in each case. The hand guard 106 is also made of plastic and has at its other end a connection eyelet 107, which comprises the housing part 1 and rests on a step 108 of the steel sleeve 3 at its abutment with the housing part 1.

The preferred use of plastic for various components of the device such. B. the collecting container 31, the handle B with handguard 106 and the cylinder pot 64 together with light metal (aluminum) for various metal parts such as the housing part 1, the entire device is light in weight and is nevertheless extremely powerful; it has a pulling force of about 1.5 tons and can process rivets with diameters up to 1/4 ".

The use of plastic for various components has the particular advantage that they can be manufactured as plastic molded parts by injection molding, which can be assembled without post-processing. In addition, these plastic parts can be colored as external parts in a desired color during manufacture, so that the device does not have to be painted.

The plastic used is preferably a glass fiber reinforced plastic of one of the polyamides.

• Wie bereits erwähnt, zeigen die Fig. 1 und b einen Längsschnitt durch das erfindungsgemäße Blindnietgerät in dessen Bereitschaftsstellung nach Anschluß der Druckluft über den Druckluftschlauch 82. Das hydraulische System ist völlig mit Hydraulikmedium gefüllt. In seiner Ruhestellung vor Anschluß der Druckluft ist der Ringraum 48 hinter dem Rückstellkolben 34 noch nicht mit Druckluft beaufschlagt; die Druckfeder 28 im Gerätekopf A ist dann entspannt, und der Rückstellkolben 34 befindet sich über dem Druckrohr 26 in seiner bis in geringen Abstand unter dem Abschlußdeckel 30 zurückgeschobenen Ruhestellung, so daß über die Druckfeder 28 kein Vakuum auf das Hydraulikmedium wirken kann, weil über die Druckfeder 28, die Druckbuchse 23 und die Futterbacken 6 keine Bewegung eingeleitet werden kann, die zu einem Vakuum in dem Hydraulikmedium führen würde.

The operation of the blind riveting device described above is as follows:

• As already mentioned, FIGS. 1 and b show a longitudinal section through the blind riveting device according to the invention in its ready position after the compressed air has been connected via the compressed air hose 82. The hydraulic system is completely filled with hydraulic medium. In its rest position before the compressed air is connected, the annular space 48 behind the return piston 34 is not yet pressurized with compressed air; the compression spring 28 in the device head A is then relaxed, and the return piston 34 is located above the pressure tube 26 in its rest position pushed back to a short distance below the end cover 30, so that no pressure can act on the hydraulic medium via the compression spring 28 because of the Compression spring 28, the pressure bush 23 and the chuck jaws 6 no movement can be initiated, which would lead to a vacuum in the hydraulic medium.

If the device is connected to the compressed air source Q, compressed air enters the space 40 between the housing extension 39 and the handle B and from there via the cavity 45 and the bore 47 into the annular space 48 in the housing part 1 between the end cover 30 and the reset piston 34; it acts on the annular surface of the reset piston 34 and moves it as far as it will go against the pull piston 15. The pressure tube 26, which is firmly connected to the reset piston 34, is also pushed into the hollow cylindrical pull piece 4, which is firmly connected to the pull piston 15, and thus the previously relieved compression spring 28 is preloaded . The blind riveting tool is now in the ready position shown in FIGS. 1 and b and is ready for use.

The mandrel of a blind rivet to be riveted is now inserted through the mouthpiece 2 into the chuck mechanism 5, 6. By depressing the control button 90, the working stroke (advance) of the blind riveting device is triggered, which is why reference is also made to FIG. 3b. The valve body of the actuating valve 91, which is designed as a 2/2-way valve, is lifted from its seat by depressing the control button 90, and the 4/2-way valve 77 is reversed into its actuating position via the control line 76 by a pneumatic negative control. The two pneumatic chambers 83 and 88 are pneumatically separated from each other in the cylinder pot 64 and the sewer pipe 80 is connected to the compressed air connection. Compressed air thus flows through the duct pipe 80 into the pneumatic chamber 88 located behind the pressure piston 67 and acts on the surface F1 below (on the rear) of the pressure piston 67 and moves it together with the plunger 69 firmly connected to it in the direction of arrow P in FIG. 2a. The plunger 69 is guided tightly on the reinforced free end of the compensating piston 66; at the same time, the compensation piston 66, which is open at the bottom of the cylinder pot, ensures pressure compensation in the interior, which is widened by the movement of the tachometer piston 69 and is determined by plunger piston 69 and compensation piston 66. The plunger 69 penetrates into the hydraulic chamber 49 filled with hydraulic medium. Thus, the throttle disk 58 of the throttle check valve 50 is brought into contact with its seat on the valve body 55 by hydraulic action, and this displaced during the further movement of the pressure piston 67 and plunger 69 as far as the stop on the flange 62 Hydraulic medium grossed throttled through the small oil 59 of the throttle plate 58, the passage bore 57 of the throttle valve body 55 and the Gohäusbohrung 51 in the hydraulic chamber 52 dos housing part 1 and acts there on the annular surface of the pull piston 15 in the pulling direction. Together with the pull piston 15, it is firmly connected to it , the chuck mechanism 5, 6 carrying pull piece 4 and also the restoring piston 34 resting thereon with the pressure tube 26 against the pneumatic force acting on the restoring piston 34 are moved in the pulling direction by the stroke required for the riveting process (approximately 22 mm); the compressed air previously introduced into the space between the end cover 30 and the return piston 34 is thereby displaced. In the pulling movement just described, the pulling mandrel of the blind rivet gripped by the chuck mechanism 5, 6 is torn off at its predetermined breaking point, forming the riveting point. With the pulling movement of the pulling member 4, the annular piston 18 attached to its periphery also enters the inside of the cylinder sleeve 9 and lies sealingly against its inner surface.

This intermediate position of the blind riveting tool after the riveting process has just been carried out is shown in FIGS. 2a and b.

When the operating button 90 is released after the riveting process, which the operator can determine by a slight kickback, the 4/2-way valve 77 switches back to its starting position, again establishing a connection between the two pneumatic chambers 83 and 88 of the cylinder pot 64 is produced, and the return of the blind riveting device to its starting or standby position, shown schematically in FIG. 3a, begins. The compressed air previously introduced into the rear pneumatic chamber 88 now also reaches the front pneumatic chamber 83 and from there via the bores 84, 84 'and the puncture 86 in the cylinder sleeve 9 into the during the pulling movement between the shoulder 10 of the cylinder sleeve 9 and the annular piston 18 created, sealed annular space 93. By pressurizing both the annular piston 18 and the return piston 34 with compressed air in the same direction, a special piston area ratio is created which enables the return piston 34 to move the pull piston 15 together with the pulling element 4 and chuck mechanism 5, 6 back into the starting position . The hydraulic medium in the hydraulic chamber 52 of the device head A can now flow back into the hydraulic cylinder 49 unthrottled through the bore 51 and the throttle check valve 50, the throttle disk 58 of which lifts off its seat, as a result of which the plunger 69 and thus also the pressure piston 67 return to their starting position be pushed back. Air displaced from the plunger 69 can escape through the interior of the open compensating piston 66.

In other words, by releasing the control button 90, pressure is again present in the line 76 and, via the larger piston area of the 4/2-way valve 77 designed as a differential pressure valve, causes a downshift in its initial position according to FIG. 3a. In this position of the valve 77, the connection of the compressed air line 82 to the cylinder chamber 88 is blocked, and instead a connection between the cylinder chambers 83 is made via the sewer pipe 80, the 4/2-way valve 77 and the lines 84 and 84 'and the piercing 86 , 87 and 88. The arrangement of the compensating piston 66 brings the area sizes of the two ring surfaces F1 'above and F1 below the pressure piston 67 to approximately the same values. In the device head A, the annular piston 18 is arranged with its annular surface F4 pressurized by compressed air. The compressed air from the previous riveting process is in the switching position described above, in which the cylinder spaces 83, 87 and 88 are connected, at the two ring surfaces F1 'and F1 of the pressure piston 67 and the ring surface F4 of the ring piston 18 at the same time. In the connected state, compressed air is always seen on the return piston 34 with its annular surface F3 'via lines 82, 40, 45 and 47, while on the other hand the hydraulic medium acts against the annular surface F3 of the tension piston 15. (The ring surfaces F1 ', F1, F2, F3, F3' and F4 are preferably flat surfaces.)

beaufschlagt. Da diese Kraft größer ist als die ihr entgegenwirkende Kraft aus (F1―F1')x Druck, werden der Tauchkolben 69 mit dem Druckkolben 67 in Richtung Bodenplatte 104 und das Zugstück 4 mit dem Futtermechanismus 5, 6 in Richtung Mundstück bewegt, so daß trotz der im Gerät verbliebenen Druckluft des vorangegangenen Nietvorgangs ein Rücklauf des Kolbensystems in seine Ausgangsstellung gemäß Fig. 3a erfolgt. Es gilt daher:

The force from (F3 'of the return piston + F4 of the ring piston) x pressure now acts in the direction of the mouthpiece 2 on the amount of oil in the cylinder chamber 52 and urges it unthrottled back through the lines 51, 57 and the recess 61 into the hydraulic chamber 49. In this case, the plunger 69 is pulled out by the force via its (front) piston surface F2 directed against the hydraulic medium

acted upon. Since this force is greater than the counteracting force from (F1 ― F1 ') x pressure, the plunger 69 is moved with the pressure piston 67 in the direction of the base plate 104 and the pull piece 4 with the chuck mechanism 5, 6 in the direction of the mouthpiece, so that despite the compressed air remaining in the device from the previous riveting process causes the piston system to return to its starting position according to FIG. 3a. The following therefore applies:

On the other hand, the following applies to the working stroke (advance) according to FIG. 3b:

As long as the ring piston 18 moves sealingly within the cylinder sleeve 9 during the resetting of the pulling device 4, 15 and the chuck mechanism 5, 6, the compressed air previously introduced to effect the previous working stroke is present on it. Towards the end of the resetting movement (cf. FIGS. 1a and b), shortly before the chuck jaws 6 with the torn mandrel located therein come into contact with the mouthpiece 2, the annular piston 18 leaves the cylinder sleeve 9. The stored compressed air flows around the annular piston 18 and passes through the drawing not visible recesses in the annular space 20 within the annular piston 18 and from there through the bore 21 in the cylinder wall of the tension member 4 in its interior. There it rinses the nozzle tube 24 and passes through the nozzle 27 formed at the end of the nozzle tube 24 with the inner surface of the pressure tube 26 at high speed and flows through the pressure tube 26 into the collecting container 31, from where it can escape into the atmosphere.

Due to the action of the nozzle 27, the escaping compressed air creates a suction directed in the direction of the collecting container 31, which sucks off the mandrel released by the chuck jaws 6 and conveys it into the collecting container 31. The tension piece 4, the pressure bush 23, the nozzle tube 24 and the pressure tube 26, which are arranged coaxially to one another and one behind the other in the device head A, thereby form the passage 94 for the torn mandrel which is continuous from the chuck mechanism 5, 6 to the collecting container 31.

By correspondingly turning the adjusting screw 92 'over the pressure relief valve 92, it is also possible to generate a permanent negative pressure in the device head A on the mouthpiece side, which holds a blind rivet inserted into the mouthpiece 2 in place even before its mandrel is fixed by the chuck mechanism 5, 6 is seized, which can be particularly advantageous when riveting items lying in a horizontal plane. With the aid of the adjusting screw 92 ', a precise, meterable, permanent connection between the intermediate space 40 and the front pneumatic chamber 83 is established via the pressure relief valve 92. In the initial position of the device (see. Fig. 1a and b) and the 4/2-way valve 77, there is then a compressed air connection from the compressed air connection 82 via the 4/2-way valve 77, the space 40, the bore 109, the dosed pressure relief valve 92 to the pneumatic chamber 83 and from there via the bores 84, 84 ', the annular space 87 and the bore 21 in the wall of the pull piece 4 into the passage duct 94 to the nozzle 27. The compressed air supplied via the hose connection is sufficient as a result of the metered Adjustment of the pressure relief valve 92 in order, on the one hand, as described above, to hold the return piston 34 in the advanced position in contact with the pulling piston 15 and thus the blind riveting tool in the ready position, and on the other hand through the outlet from the nozzle 27 via the above-mentioned path in the passage 94 and thus to generate a negative pressure on the mouthpiece 2, which holds the blind rivet inserted into the mouthpiece 2 in place, but then a constant, however h Limited compressed air supply is required.

The blind riveting device according to the invention can thus be converted by a simple measure - turning the adjusting screw 92 '- from a device with intermittent compressed air supply, in which the inserted blind rivets are not held in the mouthpiece 2 by negative pressure, into a device with a constant, but in comparison compressed air supply reduced to the prior art, in which the blind rivets are held in the mouthpiece 2 by negative pressure.

The blind riveting device according to the invention can be further transformed in an advantageous manner. Under certain conditions, e.g. B. for space reasons, ejection of the mandrels to the rear can be undesirable and even impossible. The blind riveting device can then be quickly and easily into a device with ejection of the mandrels forward, i. H. through the mouthpiece 2. For this purpose, the steel sleeve 3 with the pressure bush 23 and the chuck mechanism 5 is unscrewed from the device head A and the nozzle tube 24 is removed to the front by the pulling element 4. If the steel sleeve 3 together with the pressure bush 23 and the chuck mechanism 5, 6 are then screwed in again, the compression spring 28 with the spacer ring 29 of course coming back to rest on the pressure bush 23, then one has an operable blind riveting tool with a mandrel ejection through the mouthpiece 2. The collecting container 31 can then be removed to gain space. The compressed air introduced (already used once) from the pneumatic cylinder 64 into the passage 94 after the riveting process has been completed does not then have to escape to the rear through a nozzle, but also flows out through the mouthpiece 2 to the front, thereby exerting pressure on the the feed mechanism 5, 6 releases the released mandrel and throws it out of the mouthpiece 2 with reduced force for safety reasons.

With the present invention it has been possible to integrate an automatic suction or ejection device for the mandrel torn off during the riveting process into the actual blind riveting device in a space-saving manner. By not releasing the compressed air introduced into the blind riveting device to effect the riveting process after the riveting process has been carried out, but by diverting it and storing it briefly until shortly before the resetting of the pulling device and the chuck mechanism in the initial position and then either through a nozzle or directly into the from the chuck mechanism to the collecting container for the torn through continuous passage, the compressed air is used twice in an energy-saving manner, namely for the actual riveting process and for the suction or ejection of the mandrel. The riveting process and the suction or ejection process can take place in succession in a closed work cycle, and the blind riveting device is then immediately ready for use again.

The blind riveting device according to the invention can be converted in a simple and quick manner, depending on the need, from the preferred suctioning off of the torn mandrels backwards to their forward ejection. Both systems are therefore combined in one and the same blind riveting tool. The only intermittent supply of compressed air saves energy and costs. By means of a simple measure, it is possible to generate a negative pressure in the device head with a compressed air supply that is reduced compared to the prior art, which holds a blind rivet inserted into the mouthpiece in its place.

Claims (18)

1. A pneumatic-hydraulic blind rivetting tool for the setting of blind rivets comprising a rivet sleeve and a traction mandrel which can be torn off with a pneumatic cylinder (64), in which a pressure piston (67) and a plunger piston (69), which is rigidly connected thereto and which plunges in a sealed manner into a connecting hydraulic chamber (49), are movable to and fro, and with a tool head (A) which connects to the hydraulic chamber (49) and in which a traction device (4, 15) carrying the chuck mechanism (5,6) for gripping the traction mandrel can be moved to and fro in a pneumatically-hydraulically controlled manner, in which respect a through passage (94) is provided in the tool head (A) for rearward ejection of the traction mandrels, which are torn off during the rivetting procedure, characterised in that the compressed air introduced into the pneumatic chamber (88) situated behind the pressure piston (67) for the performance of a rivetting operation can be introduced in the ejection direction into the through passage (94) after the rivetting operation has been accomplished by reversal of a valve (77) and by way of bores (84,84', 21), provided in the blind rivetting tool.

2. A blind rivetting tool according to claim 1, characterised in that the compressed air can be introduced in the ejection direction into the throughpassage (94) through a nozzle (27) situated behind the traction mandrel.

3. A blind rivetting tool according to claim 1 or 2, characterised in that arranged concentrically in the throughpassage (94) is a nozzle tube (24) which leaves an interspace relative to the inner wall of the throughpassage (94), the end of the tube averted from the chuck mechanism (5, 6) being expanded radially in the direction of the wall of the throughpassage (94) so as to form a nozzle or the nozzle (27) respectively, in which respect the compressed air can be introduced through a bore (21) in the wall of the throughpassage (94) into the interspace between the inner wall of the throughpassage (94) and the nozzle tube (24).

4. A blind rivetting tool according to one of claims 1 to 3, characterised in that the throughpassage (94) is formed by a hollow-cylindrical traction piece (4) which is arranged coaxially in the tool head (A) and which bears at its one end the chuck mechanism (5, 6) and at its other end a traction piston (15) which is tightly displaceable in the tool head (A), as well as by a pressure tube (26) which is inserted from the side of the traction piston (15) into the traction piece (4) and which pierces the sealing cover (30) of the tool head (A).

5. A blind rivetting tool according to claim 4, characterised in that one end of the nozzle tube (24) rests sealingly on a pressure liner (23) arranged inside the traction piece (4) and resting on the chuck jaws (6) of the chuck mechanism, while the expanded end of the nozzle tube (24) forming the nozzle (27) projects into the pressure tube (26), in which respect a compression spring (28) surrounding the nozzle tube (24) is arranged between the pressure liner (23) and the pressure tube (26).

6. A blind rivetting tool according to one of claims 1 to 5, characterised in that associated with the traction piston (15) is a further piston (restoring piston 34) by means of which the compression spring (28) can be relieved.

7. A blind rivetting tool according to one of claims 4 to 6, characterised in that the traction piece (4) is surrounded beneath the traction piston (15) by a cylinder sleeve (9) which has, at its end facing the traction piston (15), a radially inwardly directed shoulder (10) against which the traction piece (4) is tightly displaceable, and which, moreover, leaves an annular space (87) adjacent the traction piece into which the housing bore (84') for supply of compressed air opens, and in that in the region of the bore (21) in the traction piece (4) for the transmission of compressed air to the nozzle (27) the traction piece (4) is surrounded by an annular piston (18) which, in the initial position of the traction piece (4), is disposed outside the cylinder sleeve (9) and through recesses (20) establishes a connection between the space surrounding it and the bore (21) in the traction piece and in the drawn-back state of the traction piece (4) is disposed inside the cylinder sleeve (9) and butts against the wall of the cylinder sleeve (9) sealing the bore (21) aginst the surrounding space.

8. A blind rivetting tool according to claim 7, characterised in that, by way of an opening (86) in the cylinder sleeve (9), the housing bore (84') opens into the annular space (93) formed in the drawn-back state of the traction piece (4) between the shoulder (10) of the cylinder sleeve (9) and the annular piston (18).

9. A blind rivetting tool according to one of the preceding claims, characterised in that the throughpassage (94) opens into a collecting vessel (31) which is mounted on the tool head (A) and communicates to atmosphere.

10. A blind rivetting tool according to one or claims 3 to 9, characterised in that, after unscrewing a sleeve (3) which contains the mouthpiece (2) and after unscrewing the chuck mechanism (5, 6) is screwed onto the tool head (A), the nozzle tube (24) can be removed forwardly through the traction piece (4) and the blind rivetting tool is operable without the nozzle tube (24) with traction mandrel ejection through the mouthpiece (2).

11. A blind rivetting tool according to one of claims 1 to 9, characterised in that the collecting vessel (31) into which the throughpassage (94) opens is securely connectable to the tool head (A).

12. A blind rivetting tool according to claim 11, characterised in that the collecting vessel (31) consists of a cup (95) with a suitably shaped sleeve (96) pushed thereover, both having at least one windowlike opening (97) in their respective walls which by rotation of the sleeve (96) relative to the cup (95) can be sealed or be brought into register.

13. A blind rivetting tool according to claim 11 or 12, characterised in that the collecting vessel (31) has air exit openings (100) in its base.

14. A blind rivetting tool according to claim 13, characterised in that the collecting vessel (31) consists of plastics material and in that its base in cut out circularly and a baffle plate (101) having air exit openings (100) is held by the remaining base ring (98).

15. A blind rivetting tool according to one of claims 1 to 9, characterised in that an adjustable excesspressure valve (92) is arranged in the pneumatic connection between the compressed air connection (82) and the throughpassage (94).

16. A blind rivetting tool according to one of claims 1 to 15, characterised in that the extents of the areas of the annular surfaces above (F1') and below (F1) the pressure piston (67) are altered relative to one another until they are of approximately equal values.

17. A blind rivetting tool according to claim 16, characterised in that the approximation of the extents of the areas of the annular surfaces above (F1') and below (F1) the pressure piston (67) is achieved by means of a compensating piston (66).

18. A blind rivetting tool according to claim 17, characterised in that the compensating piston (66) is, on the one hand, fastened to the cylinder cup base and, on the other hand, projects coaxially into the plunger piston (69) as far as the region of the flange (62) of the handle (B) which is averted from the tool head (A).

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