EP0165282B1 - pneumatic sensor for the control of pneumatic cycles - Google Patents

Abstract

Improvement to pneumatic sensors for the control of pneumatic cycles wherein a fluid jet pump is supplied at the inlet by a compressed air circuit and is connected at the outlet to a nozzle the stopping of which causes a pressure rise in the fluid jet pump, said rise being used as a control signal of a pneumatic component. The space (4) comprised between the jets (2, 3) of the fluid jet pump is connected on one hand to an outlet orifice (14) emitting the control signal and on the other hand to an air vent valve (13b) which, open during the ejection escape, lets the atmospheric pressure into the space (4), the outlet (14) and the conduit (15) preventing the formation of a depression, and which is closed during the obturation of the escape. The invention is used for the control of pneumatic cycles.

Description

The present invention relates to a pneumatic sensor for controlling pneumatic cycles.

Pneumatic sensors are known which are the subject in particular of GB-A 1 428 887 in which a vacuum pump is used supplied at the inlet by a compressed air circuit and connected at the outlet to a leakage nozzle, the obturation causes a rise in pressure in the tube which is transmitted to a pneumatic relay capable of transmitting a pneumatic signal. The space between the nozzles of the proboscis is connected to an outlet opening emitting the control signal. However, the pneumatic relay is very complex and includes a set of membranes and valves.

To remedy this drawback, a very simplified device is used according to the invention, giving very good results.

In accordance with the invention, the space between the nozzles of the proboscis is connected on the other hand to a vent valve which, open during the ejection leak, admits atmospheric pressure in space, l outlet and the conduit supplying the control signal to the pneumatic component, preventing the creation of a vacuum and which is closed during sealing of the leak, the supply pressure discharging and being established in the outlet, the conduit thus forming the pneumatic pressure signal.

The device according to the invention therefore makes it possible to replace a relay or a "yes" cell with a valve canceling the vacuum of the vacuum tube and thus allowing in a simple way the use of a tube for the emission of a signal. piloting a pneumatic component.

The device is very simple because it allows the use of fittings instead of complex devices with membranes of the seats and multiple valves.

The pressure rise and the signal are obtained by closing the leakage circuit which can be a simple orifice but also leakage contactors of all types.

The leakage circuit can be integrated into signal limit switch devices, but it can also be controlled electrically or pneumatically.

The signal emitted by the sensor can actuate all conventional dispensing devices of all types remotely.

The pneumatic signal emitted can be integrated into the device and it can be transformed into an electrical signal.

Finally, the device allows rapid unstacking by limited suction.

• la figure 1 est une vue en coupe d'un capteur pneumatique suivant l'invention relié à un circuit pneumatique comportant un vérin et son distributeur et aussi un autre distributeur;
• la figure 2 est une vue en coupe d'une variante de realisation d'un capteur pneumatique suivant l'invention;
• la figure 3 est une vue d'un circuit pneumatique comportant un capteur en forme de raccord;
• la figure 4 est une vue en élévation d'un capteur sous forme de raccord banjo;
• les figures 5 et 6 sont des vues d'un circuit pneumatique muni du capteur représenté à la figure 4;
• la figure 7 est une vue en élévation d'un capteur sous forme de raccord en T;
• la figure 8 est une vue d'un circuit pneumatique muni du capteur représenté à la figure 7;
• la figure 9 est une vue en coupe d'un mode de réalisation de l'ajutage de fuite;
• les figures 10 et 1 Oa sont des vues en coupe d'un ajutage de fuite comportant un clapet et une commande à bille;
• les figures 11 et 11 a sont des vues en coupe d'un capteur comportant un moyen d'obturation de l'ajutage de fuite muni d'un galet de commande;
• les figures 12 et 12a sont des vues en coupe d'un capteur intégré à un appareil avec un ajutage de fuite et un obturateur;
• la figure 13 est une vue en coupe d'un distributeur muni de capteurs pneumatiques intégrés;
• la figure 14 est une vue en coupe d'un distributeur comportant un capteur intégré commandant par un moyen électrique, l'obturation de la fuite;
• la figure 15 est une vue en coupe d'un capteur sous forme de raccord commandant par un moyen électrique, l'obturation de la fuite;
• la figure 16 est une vue en coupe d'un capteur comportant un signal de sortie électrique.

Other characteristics and advantages of the invention will be better understood on reading the following description of several embodiments and with reference to the appended drawings, in which:

• Figure 1 is a sectional view of a pneumatic sensor according to the invention connected to a pneumatic circuit comprising a cylinder and its distributor and also another distributor;
• Figure 2 is a sectional view of an alternative embodiment of a pneumatic sensor according to the invention;
• FIG. 3 is a view of a pneumatic circuit comprising a sensor in the form of a connector;
• Figure 4 is an elevational view of a sensor in the form of a banjo fitting;
• Figures 5 and 6 are views of a pneumatic circuit provided with the sensor shown in Figure 4;
• Figure 7 is an elevational view of a sensor in the form of a T-connector;
• Figure 8 is a view of a pneumatic circuit with the sensor shown in Figure 7;
• Figure 9 is a sectional view of an embodiment of the leakage nozzle;
• Figures 10 and 1 Oa are sectional views of a leakage nozzle comprising a valve and a ball control;
• Figures 11 and 11 a are sectional views of a sensor comprising a means for closing the leakage nozzle provided with a control roller;
• Figures 12 and 12a are sectional views of a sensor integrated into an apparatus with a leakage nozzle and a shutter;
• Figure 13 is a sectional view of a dispenser with integrated pneumatic sensors;
• Figure 14 is a sectional view of a dispenser having an integrated sensor controlling by electrical means, closing the leak;
• Figure 15 is a sectional view of a sensor in the form of a connector controlling by electrical means, the sealing of the leak;
• Figure 16 is a sectional view of a sensor having an electrical output signal.

In Figure 1 there is shown an embodiment of a pneumatic sensor according to the invention which comprises a body 1 having the shape of a fitting and internally comprising a vacuum pump consisting of a nozzle 2 of small diameter and d a nozzle 3 of larger diameter than the nozzle 2, a space 4 being provided between the two nozzles.

The nozzle 2 opens into a threaded pipe 5 which is connected by a conduit 6 to a source of pressurized fluid 7 or to the fluid escaping from the jack via a distributor 8 supplying a jack 9 comprising a piston 9a.

The nozzle 3 opens into a threaded tube 10 which is connected by a conduit to a leakage nozzle 11 from which an air jet escapes and which can be closed by a closure member 12 mounted at the end of the rod 9b of the jack 9. The space 4 located between the nozzles of the proboscis is connected on the one hand to a valve seat 13 having orifices 13 !!, capable of being closed by a thin elastic washer 13b forming one-way valve and on the other hand it opens into a threaded pipe 14 for outputting a control signal itself connected by a conduit 15 to a member to be controlled, in particular a distributor 16.

• Lorsque le conduit 6 est relié à la source de fluide sous pression 7 et que l'organe obturateur 12 se trouve dans la position représentée à la figure 1 le fluide s'échappe par l'ajutage 11 vers l'atmosphère et la trompe à vide 2, 3, fonctionne normalement assurant l'ouverture du clapet 13 qui est relié à l'atmosphère, la dépression de la trompe à vide ne peut donc se créér, le conduit 15 reste donc à la pression atmosphérique sensiblement et aucune action de pression ou dépression n'agit par le conduit 15, donc aucun signal pneumatique n'agit sur le distributeur 16 qui reste stable. Il faut en effet éviter «d'aspirer» les tiroirs de distributeurs, ceux-ci ne devant être que poussés par un signal de pression. Ceci est bien réalisé par l'invention grâce au clapet de mise à l'atmosphère 13b.

The sensor works as follows:

• When the duct 6 is connected to the source of pressurized fluid 7 and the shutter member 12 is in the position shown in FIG. 1 the fluid escapes through the nozzle 11 towards the atmosphere and the vacuum pump 2, 3, operates normally ensuring the opening of the valve 13 which is connected to the atmosphere, the vacuum of the vacuum tube cannot therefore be created, the conduit 15 therefore remains at atmospheric pressure substantially and no pressure action or vacuum acts by the conduit 15, therefore no pneumatic signal acts on the distributor 16 which remains stable. It is indeed necessary to avoid "vacuuming" the dispenser drawers, these only having to be pushed by a pressure signal. This is achieved by the invention thanks to the vent valve 13b.

The piston 9a moving along the arrow F when it arrives at the end of the race, the shutter member 12 closes the nozzle 11 so that the pressure of the fluid discharges and increases in the space 4 of the proboscis and that the valve 13b closes. The pressure propagates in the conduit 15 giving a pressure signal which controls the distributor 16 whose drawer changes position. During the re-entrant rod stroke of the jack 9, (in the opposite direction to the arrow F) the horn 2, 3 is again supplied with the air escaping from the jack towards the atmosphere; the vacuum pump accelerates the removal of the valve 16 until the pressure equals atmospheric pressure, the valve 13b being automatically on the atmosphere at the slightest depression. De-piloting is therefore much faster than by natural emptying. The circuit 15 very quickly regains substantially the atmospheric pressure.

It would be the same in the case of a permanent supply at the inlet 17, the diagram shown making it possible to limit the duration of the leak to the sole duration of the supply to the jack and thus to limit the air consumption of flight.

In Figure 2 there is shown an alternative embodiment of a sensor in which a signal amplification means allows the simultaneous and rapid control of several distributors. This signal amplification means comprises a channel 18 connected on one side with the supply inlet pipe 5 and on the other side with a chamber 19 connected by a channel 20 to the pipe 24 of the output signal .

The orifice of the channel 18 is closed by the central part of a membrane 21 or of a piston subjected to the action of a spring 22 bearing against a valve body 23. When the nozzle is closed off 11 fluid leakage pressure in the sensor, acting on the entire membrane 21 opens the channel 18 releasing a large amount of fluid from the compressed air inlet to the pilot outlet 14 through the chamber 19 and the channel 20 which is connected to it.

In Figure 3 there is shown a connector-shaped sensor in which the body 24 which comprises a passage conduit 25 whose inlet 5 is connected to the source of pressurized fluid 7 by the distributor 8, said conduit 25 being connected to the horn 2, 3 and having an outlet for pressurized fluid which is connected by a conduit 26 to one of the chambers of the jack 9. The pipe 4 emitting the control signal is connected by a conduit 27 to the inlet of the actuator control means 8.

In Figure 4 there is shown a sensor which consists of a banjo connector 31 and a screw 28 mounted directly in a threaded hole 29 of an apparatus 30 which supplies the relay and the cylinder with compressed fluid. The banjo 31 sensor is surmounted by a simple banjo 32. The direct supply circuit passes through 32 and the sensor 31 is supplied with bypass.

In the embodiment of Figure 5, the screw 28 is mounted on the distributor 8, and the body 31 has a tube 10 connected to the leakage nozzle 11 and a tube 14 for signal output connected to the command input the distributor 8 through the conduit 27.

The other body 32 connects the inlet for pressurized fluid through a tube 33, to the conduit 26 for supplying one of the chambers of the jack 9.

In the embodiment of Figure 6, the screw 28 is mounted on the cylinder body, the body 31, being connected by its tubing 10 to the fluid nozzle 11, and the tubing 14 for output of the control signal to the distributor 8 by a conduit 27. The other body 32 is connected by a conduit 26 to the distributor 8.

In Figure 7 there is shown a T-shaped connector body which is similar to that of Figure 1, but in which the nozzles 2 and 3 of the proboscis are produced directly in the body and said body 1 of the sensor is associated to a fitting 34 in T to ensure the control of the functioning of the jack 9 (fig. 8).

In Figure 7 the outputs are instant connections for tubes.

In Figure 9 there is shown an embodiment of a leakage nozzle 11 which is formed in a plate 35 of an apparatus and which is connected by a conduit 36 to the pipe 10 of the relay.

On the plate 35 moves a member 37 linked to a control means and which is capable of closing the orifice of the leakage nozzle 11 according to a known method but in the associated invention for interrupting the leak.

In Figures 10, 10a there is shown a leakage nozzle 11 which is closed by a valve 37 subjected to the action of springs and comprising a ball 38 which cooperates with a movable member 39 integral in particular with an actuator rod according to a method known, but in the invention associated with it for the interruption of the leak.

In Figures 11, 11a, there is shown a means for closing the leakage nozzle which is integrated into the body of the sensor. In this case, the leakage nozzle 11 has its opening controlled by a valve 40 controlled by a lever 42 against the action of a spring 41, said lever 42 being articulated around an axis 43 on the body 1 of the sensor and carrying at its other end a roller 44, cooperating with a movable member 45 in the form of a cam, in order to open and close the orifice of the nozzle 11.

Figures 12 and 1 2a, there is shown a sensor which is integrated at the end of the body 46 of any device, said body 46 being located opposite a shutter member 47 which by sliding on the latter closes the 'leakage nozzle 11.

In Figure 13 there is shown a dispenser comprising a body 48 in which is mounted slide und drawer 49 and which comprises at its two ends of the sensors controlling the movement of the drawer. In fact, the conduits 14 delivering a control signal when the leakage nozzles 11 are closed, opens opposite the ends of the drawer 49 in order to move the latter to the right or to the left. The orifices the sensors are connected by conduits 50, 50a to the fluid inlet orifice in the body 48 of the distributor. The leakage circuit can be closed all along the circuit 11. In particular, a “manual” control can be installed on the circuit 11 in addition to the leakage circuit. Manual control closing the circuit. The pneumatic signal is transmitted through line 14 to the distributor.

In Figure 14 there is shown a sensor mounted at one end of the distributor as in Figure 13, however the opening and closing of the leakage nozzle 11 are controlled by a valve 51 which is actuated magnetic metal in the closing direction by an electromagnet 52 connected to an electrical circuit.

In FIG. 14, as in FIG. 15, manual control of the signal can easily be obtained by closing the leak with your finger; one can also push the valve 51 on its seat to close the leak. The valve 51 can also be equipped with a push button to facilitate finger operation. Leakage protection can also be provided to avoid inadvertent manual operations.

On the suction, it can also be useful to have a protection against the plugging of the holes in the valve seat 13, with the fingers, which would provide untimely suction of the dispenser drawers. Air filtration may also be necessary to keep the valve seat clean.

In Figure 15 there is shown a sensor whose body 1 is capable of being connected to a fluid inlet conduit by its threaded pipes 5, 5a. As in the previous example, the leakage nozzle 11 is controlled by a valve 51 actuated in the closing direction by an electromagnet 52. The pneumatic signal leaves through the pipe 14.

In Figure 16 there is shown a sensor whose body 1 receives an enclosure 53 in which is disposed a contactor 54 whose control member 55 is supported against a deformable membrane 56 closing a chamber 57 into which opens a conduit 14 emitting a pressure signal when closing the nozzle 11.

As a result there is a deformation of the membrane 56 which actuates the member 55 of the contactor 54 which emits an electrical signal corresponding to the pneumatic signal from the sensor.

FIGS. 15 and 16 constitute what are currently called electro-pneumatic interfaces, transforming thanks to the invention the pneumatic signal into an electrical signal and vice versa.

The invention finds its field in the control of cycles of pneumatic cylinders, and in the pneumatic control of machine cycles.

• 1 ° - Le circuit de fuite peut être soit intégré aux appareils, soit obturé à distance.
• 2° Le signai émis par le capteur peut soit être intégré aux appareils, soit commander un organe à distance.

There are four possibilities of combining the devices with the device according to the invention:

• 1 ° - The leak circuit can either be integrated into the devices, or closed off remotely.
• 2 ° The signal emitted by the sensor can either be integrated into the devices, or control an organ remotely.

Of course, the invention is not limiting and those skilled in the art may make modifications to it without departing from the scope of the invention.

Claims (9)

1. Pneumatic pickup for controlling pneumatic cycles, in which a vacuum pump or siphon (2, 3, 4) is supplied at the inlet (5) by a compressed air circuit and connected at the outlet (10) to a leakage nozzle (11) of which the obturation causes a pressure rise in the siphon utilised as a signal for controlling a pneumatic component (16) and the space (4) comprised between the jets (2, 3) of the siphon is connected on the one hand to an outlet orifice (14) transmitting the control signal, characterised in that the space (4) is connected on the other hand to a valve (13b) for venting to the ambient atmosphere which whilst open during the ejection discharge admits atmospheric pressure into the space (4), the outlet orifice (14) and the pipe (15), convey ing the control signal to the pneumatic component (16), preventing the creation of a negative pressure and which is closed during the obturation of the discharge, the supply pressure being stemmed and establishing in the outlet orifice (14), the pipe (15), thus forming the pneumatic pressure signal.

2. Pickup according to claim 1, characterised in that the pickup comprises a member (1) incorporating three connection openings (5, 10, 14) connected, respectively, to the compressed air inlet, to the discharge nozzle (11) and to the outlet pipe (15) transmitting the control signal, the said member incorporating the two jets (2, 3) of the vacuum siphon between which is situated the space (4) which is connected at one side to an orifice in which is installed the valve (13b), and at the other side to the orifice (14) transmitting the control signal.

3. Pickup according to claim 2, characterised in that the member (1) has installed in it an output amplifier for the control signal, comprising a valve (21, 22, 23) having a diaphragm or piston (21) obturating a derivation pipe (18, 21) opening on the one hand at the orifice (5) for inflow of compressed air and on the other hand at the orifice (14) of the control signal.

4. Pickup according to claim 2, characterised in that the member (1) comprises a duct (25) for passage of compressed air and of which one of the extremities is connected to a distributor (8) and of which the other extremity is connected to one of the chambers of a ram (9), the said duct being connected in its central part to the jets (2, 3) of the siphon.

5. Pickup according to claim 2, characterised in that the member (1) is formed by a double banjo union of which the screw (28) is attached to the utilisation device and connected to the compressed air inlet, one of the elements (31) of the banjo containing the vacuum siphon (2, 3, 4) and the valve (13b) for venting to the ambient atmosphere and comprising a compressed air inlet opening, an outlet orifice for the control signal and an orifice connected to the discharge nozzle, the other element (32) being connected to a compressed air inlet and outlet supplying another device.

6. Pickup according to claim 2, characterised in that the member (1) of the pickup has installed on it a valve (40) controlling the aperture of the discharge nozzle (11), the said valve (40) being controlled by a lever (42) articulated at (43) on the member (1) and having at one of its extremities a roller (44) coperat- ing with a movable element (45).

7. Pickup according to claim 2, characterised in that the members (1) of two pickups are integrated in the two extremities of the member (48) of the distributor and the compressed air inlet orifices are connected via a pipe (50) to the compressed air inlet of the distributor (48, 49) the orifices (14) supplying the output signals leading to each extremity of the distributor valve (49).

8. Pickup according to any one of claims 1 to 7, characterised in that the obturation of the orifice of the discharge nozzle (11) is controlled by a valve (51) operated by means of an electrical or pneumatic or manual device (52).

9. Pickup according to any one of claims 1 to 7, characterised in that the pneumatic control signal acts on a device (53, 55, 56) converting the pneumatic signal into an electrical signal.

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