WO2020031101A1

WO2020031101A1 - Head for capping screw-top bottles

Info

Publication number: WO2020031101A1
Application number: PCT/IB2019/056713
Authority: WO
Inventors: Cristiano FRANCIONI
Original assignee: F.C. Di Francioni Cristiano & C. - S.R.L.
Priority date: 2018-08-08
Filing date: 2019-08-07
Publication date: 2020-02-13

Abstract

Head (10) for closing screw-top bottles comprising a first part (11), a second part (18) for screwing the cap to the bottle, and an apparatus for transmitting tightening torque from said first part to said second part comprising an electric circuit (17), where induced electrical current is adapted to flow, and a magnetic field generator (20) generating a magnetic field adapted to invest said electric circuit (17), said electric circuit being arranged on said first part (11) and said magnetic field generator being arranged on said second part (18), or vice versa, so that when said first part (11) is rotating and said second part (18) is released from the cap to be screwed, said second part (18) rotates together with said first part (11), whilst when said second part is coupled to the cap to be screwed during the step of screwing onto the bottle, said first part (11) and said second part (18) rotate relative to each other, wherein in said electric circuit (17), immersed in the magnetic field of said magnetic field generator (20), an induced electrical current is generated, adapted to realize the cap tightening torque on said second part (18).

Description

“HEAD FOR CAPPING SCREW-TOP BOTTLES”

DESCRIPTION

Technical Field

The present invention relates to machines for capping screw-top bottles or packages; in particular, the object of the invention is a head for capping screw- top bottles, adapted to be fixed to a capping machine.

State of the Art

As it is well known, machines for capping screw-top bottles comprise a capping head that allows controlling the tightening torque of the cap on the bottle. Too low torque results in inadequate capping, while too high torque results in the breakage of the threads of the cap or bottle, or to an excessive closing.

In general, a capping head comprises an outer part fixed to a rotating member according to an axis corresponding to the rotation axis of the top on the bottle, which is part of the capping machine and generates the cap torque.

Inside the outer part there is arranged an inner part, not integral therewith.

Between the outer part and the inner part a friction is provided, i.e. a device for transmitting the cap torque from the outer part (that is, from the rotating member to which the outer part is fixed) to the inner part.

The inner part comprises a device for coupling to the cap to be screwed onto the bottle, also called “cap pusher”, practically making the inner part integral with the cap.

The cap torque transmission device, i.e. the clutch, is usually adjustable to regulate the cap torque.

Among the known cap torque transmission devices there are the following.

A) Disk clutch. A mechanical friction consisting of a series of packed disks pressed by a spring. The cap torque can be adjusted by acting on the spring compression. The disadvantage of this transmission device is that it is not easy to be set, and therefore it is not possible to have the same tightening torques on machines working in parallel. Further disadvantages are the significant wear and the high variability of the transmission torque during the same working cycle.

B) Magnetic clutch. It is comprised of of several magnets attracting one another. The cap torque can be adjusted by varying the distance between the magnets. The advantage of this transmission device is the lack of wear and the possibility of transmitting constant torque while working, even in case of high torque values. However, on the other hand, setting this device is complex and it is very difficult to set in the same manner heads working in parallel, as even minimal changes in the distance between the magnets (lower than the limit of accuracy of regulation) results in significant changes in torque. A capping head with magnetic clutch is disclosed for example in US 5.313.765.

C) Hysteresis magnetic clutch. It is comprised of permanent magnets and a conductive metal disk. There is no contact between the parts, and the tightening torque is due to the current induced in the metal disk that are transformed into heat. The torque can be adjusted by regulating the distance between metal disk and magnets. The advantage of this transmission device is the lack of wear, the possibility of transmitting constant torque while working, and the absence of vibrations. However, with this device equal heads working in parallel have different responses as the distance between the magnets is controlled by mechanical adjustments, and even small variations result in significant changes of torque, and it is therefore easy to have different responses by equal heads. Moreover, the transmissible torque value is low and varies with the temperature.

D) Torque control of the rotation motor of the rotating member. In this case, the adjusting head does not consist of two parts rotating relative to each other with the interposition of a clutch, but it consists, in practice, of making the “cap pusher”, i.e. the device for coupling to the top to be screwed, integral with the rotation member of the capping machine. The transmission torque supplied to the rotating member, which is directly provided with“cap pusher”, is directly adjusted on the electric motor generating it. The advantages of this solution are a digital adjustment of the torque, i.e. a very accurate adjustment, duplicable for all the capping heads. The disadvantages of this solution are the hf costs, the low production speeds due to inertia of the mechanical parts connected to the motor, and to the disturbances caused by the actuation generated by the current.

Object and summary of the invention

The object of the invention is to overcome the drawbacks of the capping heads of the prior art.

More in particular, an important object of the present invention is to provide a head for capping screw-top bottles that allows easily adjusting the cap torque.

A further important object of the present invention is to provide a head for capping screw-top bottles that is constant during use.

A further important object of the present invention is to provide a head for capping screw-top bottles that is economical to be produced.

A further important object of the present invention is to provide more distinct heads, adapted to supply the same cap torque.

A further important object of the present invention is to provide a head for capping screw-top bottles with high-precision torque.

A further important object of the present invention is to provide a head for capping screw-top bottles wherein the cap torque remains constant as the temperature varies.

A further important object of the present invention is to provide a head for capping screw-top bottles that is not subject to wear.

A further important object of the present invention is to provide a head for capping screw-top bottles producing no vibrations (or limited vibrations) during use.

A further important object of the present invention is to provide a head for capping screw-top bottles that is compact and strong.

These and other objects, that will be better described below, are achieved through a head for capping screw-top bottles, comprising:

- a first part, provided with a fastening equipment for fastening to a rotation member outside the head, adapted to drive said first part into rotation around a main axis coinciding with the rotation axis of the cap on the bottle,

- a second part carrying a device for coupling to the cap to be screwed onto the bottle, said second part comprising a rotary coupling to said first part around said main axis, so that said first part and said second part can rotate relative to each other around said main axis,

- an apparatus for transmitting tightening torque from the first part to the second part,

the characteristic of the invention is that the tightening torque transmitting apparatus comprises an electric circuit, where induced electrical current is adapted to flow, and a magnetic field generator generating a magnetic field adapted to invest the electric circuit, the electric circuit being arranged on the first part and the magnetic field generator being arranged on the second part, or vice versa,

so that when the first part is rotating and the second part is released from the cap to be screwed, the second part rotates due to inertia together with the first part, whilst when the second part is coupled to the cap to be screwed during the step of screwing onto the bottle, the first part and the second part rotate relative to each other, wherein in the electric circuit, immersed in the magnetic field of the magnetic field generator, an induced electrical current is generated, adapted to realize the cap tightening torque on the second part.

In practice, the capping head can be intended as an alternator or a dynamo connected to a rotating member (for instance a further electric motor) supplying mechanical energy, converting it into electric energy, which is in turn converted again into mechanical torque.

Advantageously, the tightening torque transmitting apparatus comprises a device for adjusting the electrical current flowing in the electric circuit during the bottle capping step, thus varying the cap tightening torque.

According to a preferred embodiment, the device for adjusting the electrical current flowing in the electric circuit comprises a regulator of the resistive load of the electric circuit.

Preferably, the regulator of the resistive load of the electric circuit comprises at least a device for coupling a resistive unit of a given pre-set value to, and releasing it from, the electric circuit, in order to allow the replacement thereof with a resistive unit of different pre-set value. The regulator of the resistive load of the electric circuit preferably comprises a plurality of resistive units of pre-set value, arranged in branches of the electric circuit, to one or more of which there are associated devices for releasing from the circuit, so that the resistive load is a function of the resistive units operatively connected to the circuit during the capping step, i.e. through which the current flows during the capping step.

The resistive units are preferably arranged electrically in parallel or in series.

According to preferred embodiments, the whole electric circuit rotates together with the part to which it is associated, i.e. with all the first part or all the second part.

According to preferred embodiments, the electric circuit comprises electric windings, subject to the magnetic field generated by the magnetic field generator, where current is induced, and at least a secondary electric circuit operatively connected the ends of the windings. The secondary electric circuit is preferably arranged, or more properly fixed to, i.e. integral with, the (first or second) part of the head where the windings are provided.

The secondary electric circuit preferably rotates integrally with the windings.

According to preferred embodiments, this first part or second part comprises a rotating sleeve adapted to receive all the electric circuit; the rotating sleeve preferably containing the windings and the secondary electric circuit, so that they can rotate together without the need for wiring outside the part and/or sliding contacts.

Preferably, the tightening torque transmitting apparatus comprises a device for adjusting the electrical current flowing in the electric circuit during the bottle capping step, thus varying the cap tightening torque; adequately, the device for adjusting the electrical current is part of, or is contained in, the secondary circuit; the device for adjusting the electrical current preferably rotates integrally with the windings.

According to preferred embodiments, the device for adjusting the electrical current flowing in the electric circuit comprises an electronic circuit for current regulation.

According to preferred embodiments, the head comprises a device for monitoring the current flowing in the electric circuit according to the time.

According to preferred embodiments, the head comprises a device for detecting the relative speed between the first part and the second part.

The secondary electric circuit preferably comprises the above mentioned electronic circuit for current regulation.

Preferably, a current rectification module is operatively arranged between the windings and the secondary electric circuit.

According to preferred embodiments, the second part of the head comprises one or more permanent magnets generating the above mentioned magnetic field adapted to invest the electric circuit, whilst the first part comprises a body carrying the electrical windings where the induced current flows.

The electronic circuit for current regulation preferably comprises a module for controlling current voltage and one or more of the following:

- a speed sensor between the electric windings and the device for coupling to the cap;

- a frequency sensor;

- a microprocessor control module;

- a module for regulating and limiting the current;

- a radio circuit;

- a module for charging the accumulator and powering the control circuit;

- an energy accumulator (battery-condensator);

- a multi-functional display with buttons for setting the values of at least number of revolutions, torque, current;

- a led indicating the right operation;

- a led indicating malfunction or alarm.

According to preferred embodiments, the first part of the head comprises an inner axial space, inside which the second part of the head is arranged rotatingly.

Brief description of the drawing Further characteristics and advantages of the invention will be more apparent from the description of some preferred, although not exclusive, embodiments, illustrated by way of non-limiting example in the attached tables of drawing, wherein:

figure 1 is a schematic cross-section of the head of the invention for capping screw-top bottles;

figure 2 is a diagram of the electric circuit of a first embodiment of the head of the invention;

figure 3 is a diagram of the electric circuit of a second embodiment of the head of the invention;

figure 4 is a diagram of the electric circuit of a third embodiment of the head of the invention;

figure 5 is a diagram of the electric circuit of a fourth embodiment of the head of the invention;

figure 6 is a diagram of the electric circuit of a fifth embodiment of the head of the invention;

figure 7 is a diagram of the electric circuit of a sixth embodiment of the head of the invention;

figure 8 is a diagram of the rotation speed of the head according to the tightening torque to be applied to a cap through a head according to one or more embodiments illustrated in figures 2 to 6;

figure 9 is a diagram of the current flowing in the electric circuit of the embodiment of the head of the invention shown in figure 7.

Detailed description of an embodiment of the invention

With reference to the above listed figures, a head for capping screw-top bottles according to the invention is indicated as a whole with number 10.

The head 10 comprises an outer first part 1 1 provided with a sleeve 12, the upper portion of which has a fastening equipment 13 for fastening to a rotation member outside the head, schematically indicated by means of a dash- dot line, integral with the electric motor of the capping machine (not shown in the figures) using the head 10. The fastening equipment 13 comprises, for instance, a seat for coupling to a fixing shank 14 of the rotation member of the capping machine. The rotation member (the shank 14) and the first part 1 1 rotate integrally around a main axis X coinciding with the rotation axis of the cap on the bottle.

Inside the sleeve 12, and integrally therewith, a stator body 15 is provided, for example an insulated laminations pack, provided with a plurality of windings 16 that are part of an electric circuit 17, also comprising a secondary electric circuit 17A operatively connected to the ends of the windings and partially housed in a housing 12A of the sleeve 12. The electric circuit 17 will be better described below. In practice, all the electric circuit 17 is arranged in the first part 11 and therefore rotates integrally. In this example, it is preferably contained in the sleeve 12 and rotates therewith.

The stator body 15 has an axial space where a second part 18 of the head is provided, supported in a rotatory manner on the first part 1 1 by a pair of bearings 19. In practice, the second part 18 is a rotor fastened to the first part 1 1 so as to rotate around the axis X. The second part 18 is provided with one or more permanent magnets 20, which practically form a magnetic field generator, whose flow invests the windings 16, i.e. part of the electric circuit 17, causing induced electrical current to flow therein.

At the lower end of the second part 18, a device 21 is provided for coupling to the cap to be screwed to the bottle, comprising for example a glass 22 (a so-called“cap pusher”) counter-shaped relative to the cap to be screwed (not shown in the figures), inside which the cap is inserted.

Inside the second part 18, and axially thereto, a translation channel is provided for a rod 23 for removing the cap from the glass 22, the rod being operatively connected to a translation actuator, not shown in the figures.

In practice, the magnetic field generator formed by the permanent magnets 20 of the second part 18 and the electric circuit 17 with the windings 16 of the first part 11 , form an apparatus for transmitting the tightening torque from the first part 1 1 to the second part 18.

From an operational viewpoint, when the first part 1 1 is rotating and the second part 20 is released from the cap to be screwed, the second part rotates due to inertia together with the first part 1 1. Conversely, when the second part 20 is coupled to the cap to be screwed during the capping step, the first part and the second part rotate relative to each other and, according to the Faraday’s law, in the windings 16, and therefore in the electric circuit 17 immersed in the magnetic field generated by the permanent magnets of the second part 20, induced electrical current is formed, adapted to obtain on the second part 20 the cap tightening torque.

According to the Faraday’s law, the value of the tightening torque is a function of the current flowing in the electric circuit 17, which depends on the resistive load thereof.

It should be noted that the windings and the secondary electric circuit, i.e. the overall electric circuit, rotate together at the same speed around the rotation axis X, as they are associated to a same rotating structure. This configuration prevents a portion of the electric circuit from rotating while the remaining portion of the electric circuit does not rotate (or rotates at a different speed), a situation which would require complex systems of sliding contacts or the like to connect electrically the two portions of the circuit.

In a first embodiment of the head 10, the electric circuit 17 is comprised of the windings 16 and a secondary electric circuit 17A operatively connected to the ends of the windings, where a given resistive load is provided by at least a resistance R. Figure 2 shows the first embodiment, where the resistance R is fixed. In this example, the electric circuit 17 also comprises a current rectification module 24 (for example a 3-phase diode bridge) arranged between the windings 16 and the resistance R.

Advantageously, the apparatus for transmitting tightening torque from the first part to the second part comprises a device 25 for adjusting the electrical current flowing in the electric circuit 17 during the bottle capping step, thus varying the cap tightening torque (see figures 3-7). The electrical current adjusting device 25 is adequately provided in the secondary electric circuit 17A; therefore, it rotates integrally with the windings (for example it is contained in the housing 12A).

According to some embodiments, the device 25 for adjusting the electrical current flowing in the electric circuit comprises a regulator of the resistive load of the electric circuit 17.

In figure 3, the regulator of the resistive load comprises a device 125 for coupling a resistive unit of pre-set value Ri to, and releasing it from, the electric circuit, in order to allow the replacement thereof with a further resistive unit of different pre-set value, chosen for example from a set of resistive units of adequate value R1 , R2...Rn. The coupling and releasing device 125 may comprise screw devices, coupling devices, snap-coupling devices etcetera. In figure 4, the interchangeable resistive load is a set of three resistances R1 , R3, R3, connected in a star-like manner.

In figure 5, the regulator of the resistive load comprises releasing devices K2...K5. In particular, a plurality of resistive units of pre-set value, for example five (r1..r5), is provided, arranged in parallel in branches of the secondary electric circuit. In this example, to four units out of the resistive units r2...r5 there are associated respective devices K2...K5 for releasing from the respective branch, so that the resistive load of a branch is null when the respective connection device is open. It is therefore possible to have discrete combinations of resistive loads according to how many releasing devices, and which releasing devices, are open or closed, as shown in the following table.

As shown in the table, for example with five resistances and four releasing devices, it is possible to vary in a discrete manner the overall resistive load according to 16 steps (R1...R6).

Figure 8 shows a diagram of the number of revolutions of the head as a function of the torque to be applied for closing the bottle.

If, for example, it is possible to rotate the first part 1 1 in a controlled fashion (i.e. at a given rotation speed) and it is necessary to have a given tightening torque at the cap, the necessary overall resistive load can be obtained by combining ordinates and abscissas in the diagram. For example, if you need to screw a cap at 1.5 Nm with the overall resistive load resistance R9, the head shall rotate at approximately 500 rpm, with R6 at approximately 900 rpm.

In case of a head rotating at constant speed, for example 1150 rpm, and a tightening torque of 1.5 Nm is required, the overall resistive load shall be equal to R5; in case the capping head rotates constantly at 650 rpm and the required tightening torque is 2 Nm, the overall resistive load shall be equal to R9.

Obviously, the same diagram can be used in the case of replaceable resistive units as described above.

In figure 6, the regulator of the resistive load comprises a potentiometer 26. Current (and therefore torque) is adjusted according to the position of the potentiometer, which varies the resistance R in parallel with the windings; the adequate combination is chosen in the same manner as for the combination or replaceable resistive units described above, but, instead of changing or combining the resistive units, the position of the potentiometer is changed. Adequately, on the potentiometer scale there is directly indicated the value of the corresponding torque.

Figure 7 shows a further embodiment of the electric circuit 17, wherein the device for adjusting the electrical current flowing in the electric circuit comprises a known electronic circuit 27 for current regulation integrated in the secondary electric circuit, for example a microprocessor, an Arduino circuit, etc., regulating the current flowing in the windings 16. The current regulation electronic circuit is adequately provided in the secondary electric circuit (it is contained, for example, in the housing 12A); therefore it rotates integrally with the first part, i.e. together with the windings.

The electronic circuit 27 is powered, for example, by means of a floating battery rechargeable by the current generated b the head (module C4 in figure 7).

In the example of Figure 7,

- E indicates a detection device for detecting the relative speed between the first part and the second part, for instance an rpm detector between the windings 16 and the cap pusher 21 ;

- C5 indicates a module for controlling current voltage, and frequency detector;

- C1 indicates a microprocessor control module;

- C2 indicates a module for regulating and limiting the current;

- C3 indicates a radio circuit;

- C4 indicates a module for charging the accumulator and powering the control circuit;

- DS indicates a multi-functional display with buttons for setting the values of number of revolutions, torque, current, etc;

- L1 indicates a led indicating the right operation;

- L2 indicates a led indicating malfunction or alarm.

The electronic circuit 27 may comprise one or more of the components listed above.

In general, in an electronic circuit to be used in the present invention the torque can be constant even with different rpm, and can be set in various manner, for example by:

- acting on a control display;

- a trimmer or potentiometer;

- acting by radio through a portable device (for instance a portable computer, a tablet, a smartphone, etc);

- acting by radio through a communication module interfacing the outside (PLC, PC, HMI or other device) through a field bus (EthernetIP, Profinet, EtherCAT, CAMBUS, Modbus, Devicenet, etc.).

The torque can be also set remotely if a radio or Wi-Fi module is provided on the electronic components associated with the electronic circuit 27.

Indicator lights may be also provided to indicate the operation status of the head.

The electronic components associated with the electronic circuit 27 can be programmed to adjust automatically more torques according to the rpm of the core relative to the head. The number of revolutions can be detected through a resolver or through the frequency of the generated electrical current (for example, in caps with security ring it is possible to have a torque equal to 5 Nm during the first 3-4 revolution in order to“pass” the security ring and a torque equal to 2 Nm to screw the cap).

Figure 9 shows the screenshot of a monitor of a device for monitoring the current flowing in the circuit, where a diagram of current as a function of time is shown.

In this diagram the behavior of current is shown according to time.

In point A the head grips the cap and put it into rotation.

The interval of time between A and B is determined by the number of revolutions of the head and by the number of threads of the cap.

In point B the tap is closed and starts to be tightened.

In point C starts the torque limitation to the set value.

In point D, through radio module or LEDs the OK signal is generated indicating the correct capping.

In point E the head releases the cap. Obviously, a device for monitoring the current will also signal any malfunction and incorrect capping.

From the description above it is clearly apparent that the capping head described above solves the drawbacks of the known capping heads, providing in practice a capping head with electromagnetic clutch.

This capping head allows high precision of the tightening torque, high repetitivity of the tightening torque during operation, also for heads working in parallel, also allowing, in some embodiments, a “digital” adjustment of the torque. Moreover, it allows transmission of high tightening torque, as well as the possibility of varying the tightening torque and of adjusting the torque during operation (for example through a model with radio module).

Moreover, the capping head described above does not have wear, can be powered by actions generated by the same head, can allows varying automatically the tightening torque. Moreover, the capping head of the invention allows monitoring the capping torque, detecting the parameters of current and voltage, thus having also a report for correct capping. Lastly, it can be programmed to have the desired variability during operation.

It is understood that what is illustrated purely represents possible non limiting embodiments of the invention, which may vary in forms and arrangements without departing from the scope of the concept on which the invention is based. Any reference numerals in the appended claims are provided for the sole purpose of facilitating the reading thereof in the light of the description hereinbefore and the accompanying drawings and do not in any way limit the scope of protection.

Claims

1 ) Head for capping screw-cap bottles, comprising

- an apparatus for transmitting tightening torque from said first part to said second part,

characterized in that said tightening torque transmitting apparatus comprises an electric circuit, where induced electrical current is adapted to flow, and a magnetic field generator generating a magnetic field adapted to invest said electric circuit, said electric circuit being arranged on said first part and said magnetic field generator being arranged on said second part, or vice versa, so that when said first part is rotating and said second part is released from the cap to be screwed, said second part rotates together with said first part, whilst when said second part is coupled to the cap to be screwed during the step of screwing onto the bottle, said first part and said second part rotate relative to each other, wherein in said electric circuit, immersed in the magnetic field of said magnetic field generator, an induced electrical current is generated, adapted to realize the cap tightening torque on said second part.

2) The head of claim 1 , wherein said tightening torque transmitting apparatus comprises a device for adjusting the electrical current flowing in said electric circuit during the bottle capping step, thus varying the cap tightening torque.

3) The head of claim 2, wherein said device for adjusting the electrical current flowing in said electric circuit comprises a regulator of the resistive load of said electric circuit; preferably

- said regulator of the resistive load of said electric circuit comprising at least a device for coupling a resistive unit of pre-set value to, and releasing it from, said electric circuit, in order to allow the replacement thereof with a resistive unit of different pre-set value,

- or said regulator of the resistive load of said electric circuit comprises a plurality of resistive units of pre-set value, arranged in branches of said electric circuit, to one or more of which devices are associated for releasing from said circuit, so that the resistive load is a function of the resistive units operatively connected to the circuit during the closing step, i.e. through which current flows during the closing step; said resistive units being preferably arranged electrically parallel or in series.

4) The head of claim 2 or 3, wherein said device for adjusting the electrical current flowing in said electric circuit comprises an electronic circuit for current regulation.

5) The head one any one of the previous claims, wherein the whole electric circuit rotates together with the part to which it is associated, i.e. with all the first part or all the second part.

6) The head of one or more of the previous claims, comprising a device for monitoring the current flowing in said circuit according to the time.

7) The head of one or more of the previous claims, comprising a device for detecting the relative speed between said first part and said second part.

8) The head of one or more of the previous claims, wherein said electric circuit comprises windings subject to the magnetic field generated by said magnetic field generator, and at least a secondary electric circuit operatively connected to the ends of said windings.

9) The head of claim 8, wherein said secondary electric circuit is integral with the part of said head where the windings are provided.

10) The head of claim 9, wherein said secondary electric circuit rotates integrally with said windings.

1 1 ) The head of one or more of the previous claims, wherein said first part or said second part comprises a rotating sleeve adapted to receive the whole electric circuit; said rotating sleeve preferably contains said electric windings and said secondary electric circuit, so that they can rotate together. 12) The head of one or more of the previous claims, where said device for adjusting the electrical current is part of, or is contained in, said secondary circuit; said device for adjusting the electrical current preferably rotating integrally with the windings.

13) The head of one or more of the claims 8 to 12, wherein a current rectification module is operatively arranged between said windings and said secondary electric circuit.

14) The head of claim 8 or 13, wherein said second part comprises one or more permanent magnets generating said magnetic field adapted to invest said electric circuit, whilst said first part comprises a body carrying said electrical windings.

15) The head of one or more of claims 8 to 14, wherein said electronic circuit for current regulation comprises a current voltage control module and one or more of the following: