FR3076551A1 - DEVICE FOR AUTOMATICALLY APPLYING A CLOSURE COMPRISING AN INTERNAL THREAD ON A CONTAINER HAVING A CORRESPONDING EXTERNAL THREAD, AND A METHOD OF APPLICATION USING THE SAID DEVICE - Google Patents

Abstract

The invention relates to a device (1) for automatic application of a closure to a container, which device (1) comprises a gripper holder (4) movable in space, a gripper (5) carried by the holder gripper (4) and rotatably mounted about a vertical axis and axially displaced along a vertical axis, and means (6) for rotating the gripper (5). The device (1) further comprises shock detection means (7) able to detect an axial shock experienced by the gripper (5) while it is rotated in the unscrewing direction of the closure relative to the container. against which the closure is put in support. The invention also relates to a closure application method using this device (1).

Description

DEVICE FOR AUTOMATICALLY APPLYING A CLOSURE

COMPRISING AN INTERNAL THREAD ON A CONTAINER PROVIDED

CORRESPONDING EXTERNAL THREAD AND APPLICATION METHOD USING THE SAME

The present invention relates to the field of the application of closures provided with threads, such as plugs or capsules, on containers also provided with threads, such as flasks, bottles, pots and the like.

The present invention relates in particular to a device for automatic application of a closure comprising an internal thread on a container provided with a corresponding external thread, as well as to a method of application using said device. The application of caps or capsules to containers can be carried out either manually by an operator, or automatically.

In the case of manual application, an operator must grasp an internally threaded plug, engage it on the external thread of the container, and perform a few turns so that the cover fits on the container. However, such a manual application is a painful and tiring task for the operator, and is of course incompatible with the high rate required by large-scale production.

Thus, various solutions for the automatic application of caps or capsules to containers have been sought.

Among the existing solutions, it is known to apply a threaded plug to a container by applying a vertical force to the plug.

Such a solution is described in particular in European patent EP0034998 which discloses a method for closing a container opening with a threaded plug, in which the threaded plug is first placed on the opening of the container, then moved to the screwing position. over the threads of the container opening by means of a force acting in the axial direction.

It is also known to apply a threaded plug to a container by detecting the position of the threads of the plug and of the container by means of vision.

However, such solutions prove to be expensive and their reliability is not guaranteed.

There is therefore a need for a solution making it possible to automatically apply a threaded plug to a container without the risk of improper positioning of the threads of the plug relative to the threads of the container, and therefore without the risk of blocking the plug and damaging the threads.

The present invention aims to solve the drawbacks of the prior art, by proposing a device for automatically applying a threaded closure to a container making it possible to ensure the alignment of the thread of the closure and of the thread of the container. before the closure is screwed onto the container, which device is more economical and more reliable than the devices of the prior art.

According to the present invention, the correct alignment of the threads is obtained by positioning the closure on the container without being concerned with the position of the threads relative to each other, then by rotating the closure in the unscrewing direction, which will cause the closure to rise until the beginning of the closure thread, namely the lower end of said thread, arrives at the start of the container thread, namely the upper end of said thread. Continued rotation in the unscrewing direction causes contact between the threads to be broken, and the closure will drop a short distance, until the start of the closure thread is stopped by the first turn of the thread. container. The closure is then in the correct engagement position, from which a screwing or pre-screwing can be carried out without risk of pre-screwing or screwing "askew", and therefore without risk of blocking. The fall of the closure to the correct engagement position leads to an axial shock transmitted to the gripper by which the closure is manipulated and whose detection makes it possible to determine that the closure is in the correct engagement position. We can then order the screwing or pre-screwing of the closure.

The present invention therefore relates to an automatic device for applying a closure comprising an internal thread on a container provided with a corresponding external thread, which device comprises a gripper holder capable of being moved in rotation about an axis vertical and in translation along three orthogonal axes, a gripper carried by the gripper holder and configured to grip and maintain the closure to be applied to the container, the gripper being mounted on the gripper holder in rotation about a vertical axis and at axial displacement along said vertical axis, and means for driving the gripper in rotation, characterized in that the rotary drive means are capable of rotating the gripper in both directions of rotation around said vertical axis and by the fact that the device further comprises shock detection means capable of detecting an axial shock which the gripper undergoes gripper while it is rotated in the direction of unscrewing the closure relative to the container against which the closure is supported by the gripper.

The device according to the invention therefore makes it possible to align the threads of the closure and of the container before any operation of pre-screwing or screwing the closure onto the container.

Preferably, the shock detection means are a shock detector connected to the gripper.

Advantageously, the rotary drive means are a motor with two directions of rotation arranged to be capable of driving the gripper in rotation, in particular by means of a belt transmission system.

Preferably, the motor with two directions of rotation is a brushless motor. The brushless motor makes it possible to know precisely the angular position of the thread both of the closure and of the container in a single movement, and therefore to reliably apply the desired screwing or pre-screwing torque.

Preferably, the gripper is in sliding pivot connection with the gripper holder, in particular by means of at least one smooth bearing.

Preferably, the device comprises means for resilient biasing of the gripper downward relative to the gripper holder. The elastic biasing means can be formed by a spring mounted around the gripper and bearing at one end on the gripper holder and, at the other end, on the gripper.

Providing such elastic biasing means ensures that a shock of sufficient intensity is obtained for reliable detection by the shock detection means, and thus increases the reliability of the device.

In a particular embodiment, the gripper comprises a cylindrical rod having an internal channel capable of being connected to a suction pipe, the rod carrying, at a lower region thereof, a gripping suction cup intended to grip the closure to apply.

The gripping suction cup can be removably connected to the cylindrical body.

The present invention also relates to a method for automatically applying a closure comprising an internal thread on a container provided with a corresponding external thread, characterized in that the application of the closure to the container is carried out 'Using a device as defined above, the method comprising the steps of: - controlling the movement of the gripper holder, so that the closure is gripped and held by the gripper, placed on the opening of the container, then pressing against the container so that the thread of the closure is in contact with the thread of the container; - Rotate the gripper, and therefore the closure, in the direction of unscrewing the closure, by controlling the rotation drive means, such rotation in the direction of unscrewing, due to the contact between the threads of the closure and of the container, causing a progressive upward movement of the gripper relative to the gripper holder until the moment when there is contact breakage at the ends of the threads of the closure and of the container, instant at which the gripper undergoes a lowering movement stopped when the lower end of the closure thread returns into contact with the container thread, which generates an axial shock in the gripper; - detecting the shock via the shock detection means; and - controlling the stopping of the rotation of the gripper in the unscrewing direction, then the rotation of the gripper, and therefore of the closure, in the screwing direction, preferably with a predetermined number of rotations.

As indicated above, the preliminary rotation step of the closure in the unscrewing direction makes it possible to correctly align the closure relative to the container, before proceeding with the screwing or pre-screwing, and therefore to avoid any risk of pre-screw or screw "askew", and therefore block the closure in an improper position.

To better illustrate the object of the present invention, there will be described below, by way of illustration and not limitation, a particular embodiment, with reference to the accompanying drawings.

In these drawings: - Figures 1 and 2 are perspective views of the device according to a particular embodiment of the present invention; - Figure 3 is a sectional view of the device of Figure 1, in a vertical plane passing through the axis of rotation of the gripper; and - Figures 4A, 4B and 4C are schematic views illustrating different stages of the implementation of the device according to the invention, Figure 4A representing the start of the application cycle, when the closure is positioned above the container , Figure 4B representing the step of rotating the closure in the unscrewing direction, and Figure 4C showing the end of the application cycle, at the time of screwing or pre-screwing.

The device 1 for automatically applying a closure 2 comprising an internal thread 20 on a container 3 provided with a corresponding external thread 30 according to the present invention can be applied to any closure 2 and to any container 3 to be screwed in. one to the other.

If we refer first to Figures 1 to 3, we can see that the device 1 according to a particular embodiment of the present invention comprises a gripper holder 4 intended to be connected to a conventional manipulator robot, a gripper 5 for closure 2 to be applied, means 6 for driving the gripper 5 in rotation, and shock detection means 7.

The gripper holder 4 generally comprises a plate 40 carrying, in its central region, means of attachment to a manipulator robot (not shown) which makes it possible to move the gripper holder 4 in the three directions of the space, namely along three orthogonal axes, and rotating about an axis perpendicular to the plate 40. These fixing means are here formed by two vertical spacers 41 whose upper ends are connected by a flange 42 having elements 43 attachment to the manipulator robot, such as holes.

The plate 40 also carries, on a first side of said fixing means, a motor 60 forming part of said drive means 6, on one side of which is provided a rotary connector 61 through which the power supply and motor control cables arrive 60.

The plate 40 carries the gripper 5 on the other side of said fastening means, which serves to grip and maintain a closure 2 to be applied to a container 3, and, by moving the gripper holder 4, the gripper 5 can be brought to the contact of a closure 2 to be applied, then positioned above the container 3 to which the closure 2 must be applied.

More particularly, the gripper 5 comprises a cylindrical rod 50 and a gripping part 51.

As can be seen in Figure 3, the rod 50 is connected to the gripper holder 4 by a sliding pivot link 8 which is here performed as follows. A candlestick 80 is mounted fixed in rotation through a through hole provided for this purpose in the plate 40, and a first smooth bearing 81 is mounted in the candlestick 80 to rotate about the longitudinal, vertical axis of the candlestick 80, with guiding in rotation by two ball bearings 82, and the lower end region of the first plain bearing 81 projects out of the lower end of the candlestick 80. The rod 50 extends through the first plain bearing 81, relative to to which it can slide along the vertical axis but it cannot rotate around the vertical axis, with additional guidance in translation by two second plain bearings 83, interposed between the rod 80 and the first plain bearing 81, each at one end of the latter.

In the embodiment shown, the gripping part 51 is a gripping suction cup directed downwards and mounted at the lower end of the rod 50. The connection between the rod 50 and the suction cup 51 can be a removable connection, allowing replace the suction cup 51 with another grip part if necessary. It should be noted that the suction cup 51 could be replaced by a clamp, or any other suitable grip part. In particular, a clamp can be mounted at the end of the rod 50 in the case where it is necessary to apply a large torque, for example to achieve engaging the closure 2 on the container 3 with a sufficient tightening torque.

In the case where the grip part 51 is a suction cup, the rod 50 is a hollow body which has an axial central channel 52 which opens at the upper end of the rod 50 for connection to a suction pipe (not shown, itself connected to a suction source (not shown) by means of a fixing connector 53 mounted in the upper part of the fixing bell 71 which will be described below, and which opens at the lower end of the rod 50 on a through hole 54 presented by the suction cup 51, so that suction can be obtained at the suction cup 51.

A compression spring 9 is mounted around the region of the rod 50 which projects below the first smooth bearing 81, which spring 9 bears on the one hand, indirectly, against said first smooth bearing 81 and on the other hand on a shoulder provided for this purpose at the lower end of the rod 50. This spring 9 makes it possible to urge the gripper 5 downwards.

The rotation drive means 6 comprise the two-directional motor 60 and a belt transmission system 62, 63, 64.

As can be seen in Figure 3, the output shaft of the motor 60 extends along a vertical axis, therefore parallel to the longitudinal axis of the gripper 5, and a first pulley 62 is coupled to the output shaft , under the plate 40. A second pulley 63 is mounted around the lower end region of the first plain bearing 81, which projects out of the candlestick 80, so as to be integral in rotation with the latter, the second pulley 63 being in the same horizontal plane as the first pulley 62. A belt 64 transmits the rotational movement of the output shaft of the motor 60, via the first pulley 62, the second pulley 63 and the plain bearings 81, 83, to the rod 50 of the gripper 5. Thus, a rotation of the motor 60 in a first direction causes the gripper 5 to rotate about its vertical axis in a first direction, and a rotation of the motor 60 in the other direction causes the gripper 5 to rotate around its vertical axis in a second direction, while giving freedom to the gripper 5 to move in translation along its vertical axis.

The two-way motor 60 is preferably a brushless motor.

However, it should be noted that the motor 60 could also be, for example, a stepping motor.

The shock detection means 7 are here formed by an analog shock detector 70 arranged to detect an axial vibration or an axial shock which the gripper 5 could undergo. The present invention is not limited to a particular technology for the shock detector. shock 7, and it is thus possible to provide other types of shock detectors.

In the embodiment shown, the shock detector 70 is carried by a fixing bell 71 made integral with the gripper 5 so that an axial vibration or an axial shock suffered by the gripper 5 is also transmitted to the bell fixing 71. Here, the fixing bell 71 has an interior space 72 in which extends the upper end of the rod 50 and with respect to which the rod 50 can rotate about its vertical axis with a rotation guide provided by two ball bearings 73. In other words, the fixing bell 71 rises and falls in one piece with the rod 50. Guiding in translation of these up and down movements is also ensured by a finger 74 s' extending radially outwards from the fixing bell 71 and the free end of which extends through a vertical guide light 75 arranged in a vertical plate 76 fixed to the spacers 41.

The shock detector 7 is connected to the control means of the rotation drive means 6, for example to a control unit, so as to inform them of the detection of a shock, by the emission of a signal. Upon receipt of the shock detection signal, an order is sent to the motor 60 to control its rotation in a particular direction of rotation.

If we now refer to Figures 4A to 4C, we can see different stages of the implementation of the device 1 according to the invention, for the automatic application of a closure 2 having an internal thread 20 on a container 3 provided with a corresponding external thread 30.

During implementation, the gripper holder 4 is moved by a manipulator robot so as to bring the gripping suction cup 51 in contact with the upper surface of the closure 2. Once the suction cup 51 is in contact with the closure 2, the suction is actuated, so that the closure 2 is held by the suction cup 51. Then, the gripper holder 4 is again moved in the space so as to position the closure 2 above the receptacle 3, the position is known, as shown in Figure 1. These steps are well known per se.

Then, the closure 2 is pressed, at least slightly, against the container 3 by a displacement of the gripper holder 4 in translation along a vertical axis, which axis is common with the axis of symmetry of the opening of the container 3, until the rod 50 of the gripper 5 rises at least slightly relative to the gripper holder 4, against the bias of the spring 9.

Once the closure 2 is placed against the container 3, the motor 60 is controlled so that the gripper 5 is rotated in the unscrewing direction of the closure 2, as shown in Figure 4B. The internal thread 20 of the closure 2 being in abutment against the external thread 30 of the container 3, rotation in the unscrewing direction of the closure 2 causes a progressive rise of the rod 50, and therefore an additional compression of the spring 9, until 'at the moment when the beginnings of the threads 20, 30 of the closure 2 and of the container 3 are no longer in contact. At this instant, owing to the fact that the spring 9 has been at least slightly compressed by the pressing of the closure 2 on the container 3 and by the ascent of the closure 2 due to the rotation in the unscrewing direction, the gripper 5 is brought to effect, under the action of the spring 9, a rapid downward movement, along the vertical axis, until the threads 20, 30 come back into contact, which generates an axial shock in the gripper 5. This shock is transmitted to the fixing bell 71 on which the shock detector 7 is mounted.

The shock detector 7 then detects the shock generated, and therefore that the closure 2 is in the correct engagement position, and informs the engine control means 60 which immediately control the stopping of the rotation of the engine 60, and therefore stopping the rotation of the gripper 5 in the direction of unscrewing the closure 2. The motor 60 is then controlled to rotate in the other direction, namely the direction of screwing of the closure 2, as shown in Figure 4C. The motor 60 can be ordered to perform a predetermined number of turns in the direction of screwing the closure 2. The number of turns may be sufficient for the closure 2 to be simply engaged on the container 3, in which case only a pre screwing of the closure 2 is carried out, or may correspond to the number of turns necessary for full engagement of the closure 2 on the container 3, in which case a screwing of the closure 2 is carried out.

Thus, the device 1 and the method according to the invention make it possible to correctly align the threads 20, 30 of the closure 2 and of the container 3 before the engagement, partial or total, of the threads 20, 30, by the detection of the shock. generated during rotation of the gripper 5 in the unscrewing direction.

It is understood that the particular embodiment which has just been described has been given by way of non-limiting indication, and that modifications can be made without departing from the present invention.

Claims (10)

1 - Device (1) for automatic application of a closure (2) comprising an internal thread (20) on a container (3) provided with a corresponding external thread (30), which device (1) comprises a holder gripper (4) able to be moved in rotation about a vertical axis and in translation along three orthogonal axes, a gripper (5) carried by the gripper holder (4) and configured to grip and maintain the closure (2) at apply to the container (3), the gripper (5) being mounted on the gripper holder (4) rotating about a vertical axis and moving axially along said vertical axis, and means for driving in rotation ( 6) of the gripper (5), characterized in that the rotary drive means (6) are capable of rotating the gripper (5) in both directions of rotation about said vertical axis and in that the device (1) further comprises shock detection means (7) capable of detecting ect an axial shock which the gripper (5) undergoes while it is rotated in the unscrewing direction of the closure (2) relative to the container (3) against which the closure (2) is supported by the gripper (5). 2 - Device (1) according to claim 1, characterized in that the shock detection means (7) are a shock detector connected to the gripper (5). 3 - Device (1) according to one of claims 1 and 2, characterized in that the rotary drive means (6) are a motor with two directions of rotation (60) arranged to be able to drive in rotation the gripper (5), in particular by means of a belt transmission system (62, 63, 64). 4 - Device (1) according to claim 3, characterized in that the motor with two directions of rotation (60) is a brushless motor. 5 - Device (1) according to one of claims 1 to 4, characterized in that the gripper (5) is in sliding pivot connection (8) with the gripper holder (4), in particular by means of at least one plain bearing (81). 6 - Device (1) according to one of claims 1 to 5, characterized in that it comprises elastic biasing means (9) of the gripper (5) downwardly relative to the gripper holder (4). 7 - Device (1) according to claim 6, characterized in that the elastic biasing means (9) are formed by a spring (9) mounted around the gripper (5) and bearing at one end on the gripper holder (4) and, at the other end, on the gripper (5). 8 - Device (10) according to one of claims 1 to 7, characterized in that the gripper (5) comprises a cylindrical rod (50) having an inner channel (52) adapted to be connected to a suction pipe , the rod (50) carrying, at a lower region thereof, a gripping suction cup (51) intended to grip the closure (2) to be applied. 9 - Device (1) according to claim 8, characterized in that the gripping suction cup (51) is connected to the cylindrical body (50) removably. 10 - Method for automatically applying a closure (2) comprising an internal thread (20) on a container (3) provided with a corresponding external thread (30), characterized in that the application of the closure ( 2) on the container (3) is produced using a device (1) according to one of claims 1 to 9, the method comprising the steps consisting in: - controlling the movement of the gripper holder (4) , so that the closure (2) is grasped and held by the gripper (5), placed on the opening of the container (3), then pressed against the container (3) so that the thread (20 ) of the closure (2) is in contact with the thread (30) of the container (3); - Rotate the gripper (5), and therefore the closure (2), in the direction of unscrewing the closure (2), by controlling the rotation drive means (6), such rotation in the direction of unscrewing, due to the contact between the threads (20, 30) of the closure (2) and of the container (3), causing a progressive upward movement of the gripper (5) relative to the gripper holder (4) up to the instant when there is a break in contact at the ends of the threads (20, 30) of the closure (2) and of the container (3), instant at which the gripper (5) undergoes a downward movement stopped when the lower end of the thread (20) of the closure (2) comes back into contact with the thread (30) of the container (3), which generates an axial shock in the gripper (5); - detecting the shock via the shock detection means (7); and - controlling the stop of the rotation of the gripper (5) in the unscrewing direction, then the rotation of the gripper (5), and therefore of the closure (2), in the screwing direction, preferably with a predetermined number of rotations.