FR3010928A1 - CARTRIDGE FOR A PNEUMATIC CIRCUIT AND SUCTION DEVICE WITH A SUCTION COMPRISING SUCH A CARTRIDGE - Google Patents

Abstract

The invention relates to a cartridge comprising a tubular body (2) having a cylindrical surface for insertion into a cylindrical housing in an axial direction (X), the cartridge being such that in said tubular body are integrated coaxially with each other: - electrical connection means (4); - control means; a first chamber (6) comprising a first lateral orifice (12) for the admission of compressed air; at least one second chamber (8) located at a second end of the tubular body and having an air outlet orifice (16; 15); - A shutoff valve (7) controlled by the control means.

Description

The invention relates to a cartridge for a pneumatic circuit that can be used in particular as a vacuum generator. The invention further relates to a suction grip device comprising such a cartridge. BACKGROUND OF THE INVENTION Vacuum generators are used in many industrial fields (automotive industry, pharmaceutical industry, etc.), for example for applications of handling or gripping products in a production line. Two main families of vacuum generators are mainly used: electric vacuum generators (vacuum pumps) and pneumatic vacuum generators. A pneumatic vacuum generator works using the Venturi effect. It comprises at least one chamber containing a nozzle through which compressed air flows, the generated vacuum resulting from a depression created by Venturi effect in said chamber. This chamber is placed in pneumatic communication with one or more suckers applied to the surface of the product. The vacuum generator draws air contained in the interior space of these suction cups and secures them to the surface of said product when the suction cups are applied against said surface. This allows manipulation or gripping of the product. The vacuum generator is also often adapted to blow air into the interior space of the suction cups to separate them from the product once handling or gripping is completed. Users of pneumatic vacuum generators are not usually specialists in vacuum generation technology: it is therefore important to design generators whose integration into a production line does not require complex operations (connections pneumatic, watertightness management, etc.). To facilitate such integration, it is also advantageous to allow users to easily adapt the external shape of these vacuum generators to their applications and their products, in order to optimize the integration of these in the chain of applications. production. Finally, it is desirable to reduce the cost of such integration to make the vacuum generation technology attractive. OBJECT OF THE INVENTION The object of the invention is to simplify the integration of a vacuum generator into a production line and to reduce the cost of such integration.

SUMMARY OF THE INVENTION With a view to achieving this object, a cartridge for a pneumatic circuit is proposed, comprising a tubular body having a cylindrical surface enabling it to be inserted into a cylindrical housing in an axial direction. The cartridge is such that in said tubular body are coaxially integrated with each other: electrical connection means located at a first end of the tubular body; control means powered and controlled via the electrical connection means; a first chamber having a first lateral port for admission of compressed air; at least one second chamber located at a second end of the tubular body and having an air outlet port; a shut-off valve arranged in the first chamber, said shut-off valve being controlled by the control means for selectively bringing into pneumatic communication the first chamber and the second chamber so as to allow an air passage to the second chamber. Such a cartridge for pneumatic circuit can be easily integrated into a vacuum generator by the user of this generator, which must only design in the generator a cylindrical housing to insert the cartridge. This integration does not require that the user has extensive knowledge in vacuum generation technology. In addition, it is relatively simple for the user to design a generator whose. external shape perfectly corresponds to a particular need, since the only structural constraint associated with the vacuum generation is the realization of the cylindrical housing of reduced size to house the cartridge. The cartridge of the invention can be used as such to blow air. It is also possible to transform this cartridge so that it can be used to suck air. It is then sufficient to provide a second port to suck air inside the cartridge: thus reduces the cost of integration for the user. In addition, a vacuum gripper device is proposed, comprising a pneumatic cartridge adapted to suck air as previously mentioned, the device comprising a body in which is formed a housing for accommodating the cartridge, an intake duct of compressed air opening into the receiving housing, a vacuum chamber which opens into the housing and which is placed in pneumatic communication with at least one suction cup, sealing means to prevent any air flow between the duct intake and the vacuum chamber by the receiving housing outside the cartridge, the device being arranged so that: - the first lateral orifice of the cartridge is in pneumatic communication with the intake duct; a second lateral orifice of the second chamber of the cartridge which is in pneumatic communication with the vacuum chamber; the device is controlled by external control means via the electrical connection means of the cartridge.

BRIEF DESCRIPTION OF THE DRAWINGS Reference is made to the accompanying drawings, in which: FIG. 1 schematically represents a sectional view of a cartridge according to a first embodiment of the invention, the cartridge being arranged so as to be normally closed; , a shut-off valve of the cartridge being in the closed position; FIG. 2 schematically represents a sectional view of the cartridge according to the first embodiment, the cutoff valve of the cartridge being in the open position; Figure 3 schematically shows a sectional view of the cartridge according to a variant of the first embodiment, the cartridge being arranged to be normally open, the cutoff valve of the cartridge being in the open position; Figure 4 schematically shows a sectional view of the cartridge according to this variant of the first embodiment, the cartridge shutoff valve being in the closed position; FIG. 5 represents a perspective view of the cartridge according to a second embodiment of the invention, a cut-off valve of the cartridge being in the closed position; Figure 6 shows a perspective view of the cartridge according to the second embodiment, a cartridge cutoff valve being in the open position; Figure 7 shows a perspective view of a cartridge of the invention according to the second embodiment adapted to blow air; Figure 8 shows a suction grip device of the invention. DETAILED DESCRIPTION OF THE INVENTION Referring to Figures 1 and 2, the pneumatic circuit cartridge 1 of the invention according to the first embodiment has a tubular body 2 having a cylindrical outer surface. The tubular body 2 of the cartridge 1 is here inserted in a cylindrical housing 3 of any vacuum generator. Inside this tubular body 2 are coaxially integrated with each other along an axis X of the tubular body 2: electrical connection means 4, a control chamber 5 comprising control means, a first chamber 6 in which is arranged a first shutoff valve 7, and a second chamber 8 having means for generating a vacuum. The electrical connection means 4 are located at a first end 9 of the tubular body and the second chamber at a second end 10 of the tubular body 2. The cartridge 1 of the invention is here adapted to generate a vacuum thanks to the means for generating the empty of the second chamber 8 which operate according to the Venturi effect. The vacuum generation means comprise a nozzle 13 attached in the second chamber 8. Said nozzle 13 has one end opening into the first chamber 6 and opposite one end opening into the second chamber 8 opposite one end of a mixer 14 coaxial with the nozzle 13. Inside the second chamber 8, the vacuum generating means form between the nozzle 13 and the exchanger 14 an annular volume of depression 17. The mixer 14 extends in the second chamber 8 and extends into a discharge opening 15 of the second chamber 8 located at the second end 10 of the tubular body 2 so that the mixer 14 has an open end disposed outside the body 2. The arrows shown in thick lines in the figures indicate that it is an air inlet or an air outlet. A first lateral orifice 12 is formed in the body 2 facing the first chamber 6 to allow an admission of compressed air into the first chamber 6. The body 2 is provided with a second lateral orifice 16 opening into the interior of the annular volume of depression 17 to put it in communication with the outside of the body 2. The compressed air flows from the first chamber 6 to the second chamber 8 through the nozzle 13 by increasing its speed, which creates a depression in the annular void volume 17, said depression generating an air suction at the second side port 16. The compressed air and the sucked air are then discharged from the cartridge through the mixer 14. The first cutoff valve 7 of the first chamber 6 is used to control this generation of vacuum or, conversely, to interrupt it. The first shutoff valve 7 is thus adapted to allow or prevent the passage of compressed air from the first chamber 6 to the second chamber 8. The first shutoff valve 7 is a two-position valve, normally closed, with a state stable corresponding to the closure of the communication between the first chamber 6 and the second chamber 8. The first shutoff valve 7 comprises a first valve 18 having a closure end 19. The first valve 18 slides along the axis of the body 2 between an open position, visible in Figure 1, wherein a first communication channel 20 adapted to put in pneumatic communication the first chamber 6 and the second chamber 8 is clear, and a closed position, in which the end capping 19 closes said communication channel 20. The first valve 18 further comprises a control end 21. The first valve defines inside the first chamber 6 u n first pilot volume 23 located on the side of the driving chamber 5, a second piloting volume 24 located on the side of the second chamber 8, and an intermediate volume 11 placed in communication with the outside to be continuously under atmospheric pressure . The role of these volumes will be explained later. When the first shutoff valve 7 is in its stable state, ie in the closed position, the communication channel 20 is closed, the compressed air can not reach the second chamber 8 and the cartridge 1 does not generate a vacuum . On the other hand, when the first shut-off valve 7 is in the open position, the first chamber 6 and the second chamber 8 are in pneumatic communication, which makes it possible to generate a vacuum. The first shut-off valve 7 is controlled by the control means of the control chamber 5 and thanks to the first lateral orifice 12 of the first chamber 6, to a pilot orifice 26 and to a first exhaust opening 27 opening outside the cartridge 1. The pilot orifice 26 is here pneumatically connected to compressed air supply means 28, just like the first lateral orifice 12. The pilot orifice 26 opens into a control chamber 29 located between the driving chamber 5 and an annular fixed body 32 provided with a seal 33, said fixed annular body 32 having a first face facing the control chamber 29 and a second face facing the first chamber 6. The first exhaust port 27 is here located in the control chamber 5 near the electrical connection means 4.

The control means comprise a control valve 34, in this case a control electrovalve, and an electrical card 35 electrically connected to the electrical connection means 4. The control of the first shutoff valve 7 is controlled by external control means 36, shown schematically in FIG. 1, which transmit a supply voltage as well as electrical control signals to the electrical board 35 via the electrical connection means 4. The electrical board 35 and the solenoid valve control 34 are electrically powered by the supply voltage. The electrical control signals are shaped by the electrical board 35 and used to generate a control current flowing in an electrical coil 37 of the control solenoid valve 34, said driving current being transmitted to the electric coil 37 when a opening of the first shutoff valve 7 and therefore a vacuum generation are controlled by the external control means 36.

The circulation of the pilot current in the coil 37 makes it possible to move a magnetic core 38 located in an internal chamber 39 of the piloting solenoid valve 34 between a rest position and an active position. When the core 38 is in its rest position, it blocks a first end of a central duct 40, the other end of said central duct 40 opening into the control chamber 29. When the core is in its active position, it closes a second exhaust duct 41 of the internal chamber of the piloting solenoid valve and in pneumatic communication with the first exhaust duct 27. When the core 38 is in its rest position, visible in FIG. 1, the air compressed fills the second pilot volume 24 of the first chamber 6 by flowing through the first lateral orifice 12, and the control chamber 29 via the pilot orifice 26. The first pilot volume 23, meanwhile, is not filled with compressed air. The second piloting volume 24 is thus raised to a pressure greater than that of the first piloting volume 23, which has the effect of producing a force on the first valve 18 which tends to bring its piloting end 21 closer to the fixed annular body 32. and to bring its capping end 19 in the position in which it closes the first communication channel 20: the first valve 18 is thus positioned in the closed position and the first shutoff valve 7 in the closed position. The compressed air thus does not reach the second chamber 8. The residual compressed air located in the internal chamber 39 of the control solenoid valve 34 is discharged through the second exhaust port 41 and through the first exhaust port 27. When the core 38 is in its active position, visible in FIG. 2, the compressed air of the pilot chamber fills the internal chamber 39 of the piloting solenoid valve 34 by flowing via the control chamber 29 and the central duct 40. As the second exhaust duct 41 is plugged, the compressed air contained in the internal chamber 39 of the control solenoid valve 34 flows towards the first pilot volume 23 of the first chamber 6 through two eccentric conduits 45 of the control electrovalve 34 each communicating with an eccentric tube 46 having an end opening facing the associated eccentric duct 45 and an end opening into the first pilot volume 23 of the first The eccentric tubes 46 thus pass through the control chamber 29 and the annular fixed body 32. Since the surface of the control end 21 is larger than that of the capping end 19, the pressure exerted by the compressed air on the control end 21 is greater than that exerted by the compressed air on the capping end 19, which has the effect of producing a force on the first valve 18 which tends to move its end capping 19 of the position in which it closes the first communication channel 20: -the first valve 18 is positioned in the open position and the first shutoff valve 7 in the open position. The compressed air thus reaches the second chamber 8, and the cartridge 1 generates a vacuum. The cartridge 1 of the invention according to the first embodiment previously described thus comprises a first shut-off valve which is "normally closed": its stable state corresponds to a valve in the closed position which does not allow the passage of compressed air in the second chamber and therefore the vacuum generation. With reference to FIG. 3, the invention can be easily implemented so as to obtain a cartridge that operates with a shutoff valve that is "normally open". In this variant, the first exhaust port 27 is pneumatically connected to the compressed air supply means 28, as is the first lateral port 12. The pilot orifice 26 then becomes a third exhaust orifice 49. core 38 is in its rest position, visible in Figure 3, the compressed air fills the second pilot volume 24 of the first chamber 6 flowing through the first lateral orifice 12, and the inner chamber 39 of the piloting solenoid valve 34 via the first exhaust port 27. As the central duct 40 is plugged, the compressed air fills the first pilot volume 23 of the first chamber 6 via the eccentric ducts 45 and the eccentric tubes 46. the surface of the pilot end 21 of the shut-off valve 7 is greater than that of the plugging end 19, the pressure exerted by the compressed air on the piloting end 21 is greater than that exerted by the compressed air on the capping end 19, which has the effect of producing a force on the first valve 18 which tends to move its capping end 19 away from the position in which it closes the first communication channel 20: the first valve 18 is thus positioned in the open position and the first shutoff valve 7 in the open position. The compressed air thus reaches the second chamber 8, and the vacuum cartridge generates a vacuum.

When the core 38 is in its active position, visible in Figure 4, the compressed air can not be introduced into the inner chamber 39 through the second exhaust port 41 which is clogged. The compressed air of the first pilot volume 23 of the first chamber 6 flows through the eccentric tubes 46 and eccentric conduits 45 into the internal chamber 39 of the piloting solenoid valve 34 and then through the central duct 40 until to the control chamber 29 from which it is evacuated through the third exhaust port 49. The pressure in the second pilot volume 24 of the first chamber 6 thus becomes greater than that in the first piloting volume 23 which tends to to bring the capping end 19 of the first of the valve 18 into the position in which it closes the first communication channel 20: the first valve 18 is thus positioned in the closed position and the first shutoff valve 7 in the closed position . It will be noted here that the pilot solenoid valve of the cartridge of the invention according to the first embodiment shown in FIGS. 1 to 4 has an operation of a three-port type valve and two positions. In a second embodiment, visible in FIGS. 5 and 6, the cartridge of the invention is equipped with a piloting solenoid valve having an operation of a two-port type valve and two positions. The cartridge of the invention 101 according to the second embodiment comprises a number of elements similar to those described above for the first embodiment, and whose references are preserved in FIGS. 5 and 6. a number of differences between the two embodiments. In the second embodiment, the eccentric conduits of the piloting solenoid valve 34 are plugged and unused. In addition, the cartridge 101 does not have a control chamber: the central duct 40 of the control solenoid valve 34 opens into the first chamber 6, said central duct 40 passing through a second fixed annular body 102. It is also noted that the cartridge 101 no longer has a pilot orifice. It is further noted that the shutoff valve is a second shutoff valve 103 different from the first shutoff valve of the first embodiment. The second shutoff valve 103 comprises a second slide valve 104 having a closure end 105 provided with a seal 106, and a compression spring 107.

The second valve 104 slides between an open position, visible in FIG. 5, in which a second communication channel 108 adapted to put in pneumatic communication the first chamber 6 and the second chamber 8 is disengaged, and a closed position, wherein the capping end 105 closes said channel 108. The compression spring 107 tends to maintain the second cutoff valve 103 in the closed position which is its stable state. The second valve 104 is hollow, and defines again in the first chamber the first pilot volume 23 into which the central duct 40 of the control solenoid valve 34 opens, and the second pilot volume 24. An internal volume 109 and a channel 110 are defined inside the second valve 104. A filter 113 and a frustoconical spring 114 are arranged in the internal volume 109, so that the spring 114 holds the filter 113 in the opposite position and in the vicinity The escape channel 110 makes it possible to place the first piloting volume 23 and the second piloting volume 24 in pneumatic communication. The compressed air therefore flows from the second piloting volume 24 into the first pilot volume 24. pilot volume 23 through the leakage channel 110 passing through the filter 113 which purifies the compressed air so as to prevent impurities from clogging the leakage channel 110. operation of the cartridge 101 according to the second embodiment. The rest position of the piloting core 38 of the piloting solenoid valve 34 again corresponds to a position in which it blocks the central duct 40, and the active position to a position in which it blocks the second exhaust port 41. Thus, when the pilot core 38 is in the rest position, visible in FIG. 5, the compressed air admitted by the first lateral orifice 12 fills the second piloting volume 24 of the first chamber 6, the internal volume 109 of the second valve 104 and the first pilot volume 23 via the escape channel 110.

As relatively close pressures are thus exerted on the surfaces of the second valve 104 located in the first volume 23 and in the second volume 24, and thanks to a compressive force exerted by the compression spring 107, the capping end 105 of the second valve 104 closes the second communication channel 108 and the second shutoff valve 103 is in the closed position. When the pilot core 38 is in the active position, visible in FIG. 6, the compressed air contained in the first pilot volume 23 escapes from it through the central duct 40 of the piloting solenoid valve 34, and is discharged from the cartridge 101 through the second exhaust port 41 and the first exhaust port 27. The pressure exerted by the compressed air on the surface of the second valve 104 located in the second pilot volume 24 is thus greater than the compressive force exerted by the compression spring 107: the capping end 105 of the second valve 104 moves away from the second communication channel and the second cut-off valve 103 is in the open position. Note that the cartridge according to the second embodiment, shown in Figures 5 and 6, has a second shutoff valve which is "normally closed". By modifying the piloting solenoid valve, it is perfectly possible to replace the second shutoff valve with a "normally open" shutoff valve. It should be noted here that the cartridge 1 described in the first embodiment of the invention and the cartridge 101 described in the second embodiment of the invention are cartridges suitable for generating a vacuum. With reference to FIG. 7, however, it is observed that if the vacuum generating means, in this case the nozzle 13 and the mixer 14, are removed from the second chamber 8, a cartridge 101 adapted to blow the air through the discharge opening 15 of the second chamber 8. The second lateral orifice 16 is then either plugged or positioned facing a surface closing said second lateral orifice. This can of course also be achieved on a cartridge according to the first embodiment of the invention. There is now described a suction pad gripper device of the invention 201, visible in FIG. 8. The gripper 201 is intended to perform a manipulation or gripping of a product 202 having a surface on which is applied a suction cup 203. For this, the gripping device 201 of the invention is here adapted to suck air contained in the inside of the suction cup 203 when manipulation or gripping is controlled, or to blow air in the air. inside the suction cup 203 when handling or gripping is completed and that it is desired to separate the suction cup from the surface 35 of the product 202.

The gripping device of the invention comprises a main body 204 in which is formed a first cylindrical housing 205 to accommodate a first cartridge 206 according to the first or second embodiment and adapted to suck air, and a second housing cylindrical 207 to accommodate a second cartridge 208 according to the first or second embodiment and adapted to blow air. The first and second cartridges 206, 208 are introduced into their respective cylindrical housing in an axial direction corresponding to the X axis of the cylindrical surface tubular body of each cartridge. The device further comprises a compressed air inlet duct 210 opening into the first cylindrical housing 205 and the second cylindrical housing 207, a vacuum chamber 211 which opens into the first cylindrical housing 205 and the second cylindrical housing 207 and which is placed in pneumatic communication with the inside of the suction cup 203. The gripping device further comprises sealing means to prevent any air circulation between the intake duct 210 and the vacuum chamber 211 by means of first and second cylindrical housings 205, 207 respectively outside the first and the second cartridge 206, 208. The sealing means here are annular seals 213 mounted on the tubular body of the first and second cartridges. The gripping device is pneumatically connected to pneumatic supply means 214 via a pneumatic connection pipe 215 which opens sealingly into the intake duct 210 of compressed air. The first lateral orifice 12 of the first cartridge 206 and the first lateral orifice 12 of the second cartridge 208 are in pneumatic communication with the intake duct 210. The second lateral orifice 16 of the first cartridge 206 and the evacuation orifice 15 of the second cartridge are in pneumatic communication with the vacuum chamber. It is noted here that this arrangement is permitted in particular by the fact that the tubular body 2 of the second cartridge 206 is shorter than that of the first cartridge 208.

The electrical connection means 4 of the first cartridge 206 and the electrical connection means 4 of the second cartridge 208 are electrically connected to external control means 217 via a common electrical connector 218 of the "T-connector" type of the gripping device. 201. The connector 218 has two first connection elements 220 each connected to the electrical connection means 4 of one of the cartridges and a second connection element 221 connected to an electrical cable 222 connected to the external control means 217. The use of this common connector 218 thus makes it possible to feed and control the electrical boards and the piloting solenoid valves of the first and the second cartridge using a single electric cable 222, which has an obvious advantage in terms of space, mass and cost of the device. The operation of the gripping device of the invention is now described. The intake duct 210 is constantly filled with compressed air supplied by the pneumatic supply means 214. When the external control means 217 controls an air intake, the shut-off valve of the first cartridge 206 is opened, and therefore the first cartridge 206 sucks air contained in the vacuum chamber 211 and thus in the interior space of the suction cup 203 which is then secured to the product 202. The compressed air and the sucked air are removed from the gripping device 201 via a mixer 14 introduced into the first cartridge 206. The shutoff valve of the second cartridge 208 is closed. When the external control means controls an air blow to separate the suction cup from the product surface, the shutoff valve of the first cartridge 206 is closed and the shutoff valve of the second cartridge 208 is open. The second cartridge 208 blows compressed air into the vacuum chamber 211 which fills the inside of the suction cup 203 with air and causes the product 202 to separate from the suction cup 203.

The invention is not limited to the particular embodiments that have just been described, but, on the contrary, covers any variant within the scope of the invention as defined by the claims.

Although a suction gripper has been described in detail, the air circuit cartridge of the invention can of course be used in different applications, for example in a pneumatic distributor.

Claims (12)

REVENDICATIONS1. Cartridge for a pneumatic circuit comprising a tubular body (2) having a cylindrical surface allowing its insertion into a cylindrical housing in an axial direction (X), the cartridge being such that in said tubular body are coaxially integrated with each other: - means electrical connection (4) located at a first end of the tubular body; control means powered and controlled via the electrical connection means (4); a first chamber (6) comprising a first lateral orifice (12) for the admission of compressed air; at least one second chamber (8) located at a second end of the tubular body and having an air outlet orifice (16; 15); - a shutoff valve (7, 103) arranged in the first chamber, said shutoff valve being controlled by the control means for selectively communicating in pneumatic communication the first chamber and the second chamber so as to allow a passage of air to the second bedroom. The cartridge of claim 1, wherein the second chamber (8) includes vacuum generating means, and wherein the second chamber includes a second side port (16) used to draw air. 3. The cartridge of claim 2, wherein the vacuum generating means operate according to the Venturi effect, wherein the second chamber comprises a nozzle (13) opening into the first chamber and the second chamber, and wherein a mixer (14) coaxial with the nozzle extends partially into the second chamber adjacent the second side port. 4. Cartridge according to claim 3, wherein the nozzle is reported in the second chamber. The cartridge of claim 1, wherein a second side port of the second chamber is used to blow air. 6. Cartridge according to one of the preceding claims, wherein the control means comprise a control valve (34) of the type with two orifices and two positions or type with three orifices and two positions. 7. Cartridge according to claim 6, wherein the control valve (34) is a solenoid valve. 8. Cartridge according to one of the preceding claims, wherein the control means comprise an electrical control card (35) connected to the electrical connection means. 9. Suction device suction pad, 20 comprising a cartridge (206) according to one of claims 5 to 7, the device comprising a body (204) in which is formed a receiving housing (205) for accommodating the cartridge, a compressed air intake duct (210) opening into the housing (205), a vacuum chamber (211) which opens into the receiving housing and which is placed in pneumatic communication with at least one suction cup (203). ), sealing means (213) for preventing any air flow between the intake duct and the vacuum chamber through the receiving housing outside the cartridge, the device being arranged so that the first lateral orifice (12) of the cartridge is in pneumatic communication with the intake duct; the second lateral orifice (16) of the second chamber of the cartridge is in pneumatic communication with the vacuum chamber; the device is controlled by external control means (214) via the electrical connection means (4) of the cartridge. A suction gripper according to claim 9, wherein the sealing means is mounted on the tubular body of the cartridge. A suction grip device according to claim 10, equipped with a first cartridge according to one of claims 5 to 7 and a second cartridge according to claim 8, the first cartridge (206) being intended to suck of the vacuum chamber (211) for gripping an object on which the suction cup (203) is applied, and the second cartridge (208) being for blowing air into the vacuum chamber to separate the object and the suction cup. A suction gripper according to claim 11 having a common electrical connector (218) to which the electrical connection means (4) of the first cartridge (206) and the second cartridge (208) are connected, the gripping device being connected to the external control means via this common connector.