FR2482515A1 - APPARATUS AND METHOD FOR ASSEMBLING LIQUID-FILLED DISPENSERS, IN PARTICULAR BY WELDING ADJACENT SURFACES OF PLASTIC ELEMENTS - Google Patents

Abstract

THE INVENTION CONCERNS AN APPARATUS AND A PROCESS FOR ASSEMBLING A DISTRIBUTION END ON A CONTAINER FILLED WITH A FLUID. THE APPARATUS INCLUDES A PROBE30 WHICH PRESENTS A CAVITY34 INTENDED TO FIT ON A DISTRIBUTION END22 NITTED BY ITS BASE IN THE THOUGHT12 OF A CONTAINER10. THE SONE30 IS CONNECTED TO AN ULTRASONIC GENERATOR, SO AS TO TRANSMIT TO THE CONTAINER10 ULTRASONIC WAVES TO WHICH THE INTERFACE BETWEEN THE BASE OF THE TIP22 AND THE CHUTE12 OF THE CONTAINER10 OPPOSES SOME RESISTANCE CAUSING A HEATING, AND, THEREFORE, FROM NOZZLE 22 TO COLUMN 12. FIELD OF APPLICATION: ASSEMBLY OF CONTAINERS INTENDED TO CONTAIN LOW VISCOSITY LIQUIDS, SUCH AS CYANO-ACRYLATE ADHESIVES.

Description

1. The invention relates to distributors, and more particularly to a

  apparatus and method for sealing dispensing nozzles of thermoplastic material

  on containers also made of thermoplastic material.

  A large number of liquid products are

  in containers to which dispensing nozzles

  are fixed. The container and the dispensing nozzle of a large number of these dispensers are made in

  any one of a very large number of thermo

  synthetic plastics. For many of these materials, it is not possible to use an adhesive to provide a seal between the dispensing tip and the container. Therefore, the seal between these two parts must be provided by the mechanical connection made between them as described, for example, in the patent of

  United States of America No. 4,138,040.

  In the case of many fluids distributed by means of these distributors, the mechanical seal behaves very well. In the case of very low viscosity fluids

  and / or fluids easily infiltrated by capillary effect.

  a mechanical seal is not always suitable. The problems posed by the resulting leaks are

  accentuated when distributors are subject to variations

  important conditions of temperature and pressure, as

  during transport in an unpressurized compartment

rised from a transport plane.

  The main object of the invention is therefore a method of welding a thermoplastic dispensing nozzle to a container, also made of thermoplastic material, of a dispenser. The method according to the invention consists in heating the interface between the dispensing nozzle and the container to make a weld between them. This heating is produced by rotating the dispensing tip and the container relative to each other, to produce sufficient heat to weld the tip to the container. The process according to the invention can be

  working in an assembly line suitable for a production

  mass production, for sealing

  dispenser on filled containers.

  2. The invention also relates to a method of welding two elements to one another by heating

  located at the interface of the elements.

  The invention further relates to an apparatus for sealing, ultrasonically, a dispensing tip on a dispenser container. This apparatus produces a relative rotation between the dispensing tip and the

container during their assembly.

  The invention also relates to an apparatus for filling, assembling and sealing dispensers of thermoplastic material, and in particular an apparatus for welding two elements to each other by localized heating.

of the interface of these elements.

  The invention will be described in more detail with reference to the accompanying drawings by way of non-limiting examples and in which - Figure 1 is a flowchart indicating several operations involved in the method of the invention; FIGS. 2, 3, 4 and 5 are elevations showing the apparatus intended to carry out the operations of the method schematized in FIG. 1; FIG. 6 is a flowchart indicating several steps of a variant of the method of the invention; and - Figures 7, 8, 9 and 10 are views showing the apparatus for the implementation of various

  schematized process operations in Figure 6.

  Many fluids are conveniently contained within dispensers having the base of a dispensing tip that is nested tightly in the neck of a container containing the fluid. This is particularly the case when the viscosity of the fluid is relatively high or when, for reasons of economy of manufacture, the surfaces in contact can have wide tolerances. In some more advanced dispensers, the neck of the container and the dispensing nozzle have annular reliefs of various shapes for making between them a mechanical seal resistant to a relatively high pressure. For most low-viscosity fluids or fluids that are relatively easily infiltrated by capillary action, most mechanical seals that can be used on mass-produced distributors, by their very nature, have too many defects to be able to ensure or establish a proper seal. This

  problem is particularly accentuated when the temperature

  ture and pressure in the container may vary

  substantially, for example during the transport of

  in the non-pressurized compartment of an airplane.

  It is possible to use adhesives instead of or in addition to mechanical seals, depending on the type and

  nature of the fluid to be dispensed and according to the constituent material

  killing the distributor. However, such adhesives can not be used if the fluid reacts with them or if they

tend to contaminate the fluid. -

  The storage and distribution of a member of the family of cyanoacrylate adhesives presents a particularly difficult problem that has not yet been solved.

  to be determined. One of the properties of a cyano-type adhesive

  acrylate is that it "infiltrates by capillarity" and that it can therefore stick to one another complementary surfaces, inaccessible to other adhesives. The same property poses a very difficult problem in the production of a cyano-acrylate adhesive dispenser, in a way that avoids

  leaks in predictable conditions.

  To be commercially competitive, cyanoacrylate adhesives and their dispensers must be manufactured by the implementation of mass production techniques which limit the degree of tolerance that can be demanded from the various elements. Tolerances

  necessarily necessary to

  an effective mechanical seal between a nozzle of

  distribution and a container filled with cyanoacrylate.

  The use of an adhesive to make such a seal is not a possible solution, because a contact of this adhesive with the cyanoacrylate causes a contamination of

  the latter, this contamination being able to cause a hardening

  4. Partial sealing and sealing of the dispensing tip,

  or may prevent hardening after the

  these consequences being unacceptable from the commercial point of view. Figure 1 shows a flow diagram

  intended for sealing the attachment of a dispensing nozzle

  on a container. This method avoids having to coat complementary surfaces with an adhesive or joint compound. The first operation consists in injecting a fluid, for example a fluid of the family of adhesives of the type

  cyanoacrylate, in the container, through the inner surface

  the neck of the latter and without contact with this inner surface. Since the cost of these adhesives per unit weight is relatively high and a very high

  small amount of adhesive is used in each application

  cation, the container is usually only partially filled

  LEMENT. During the second operation, the base of the dispensing nozzle is introduced into the neck, of complementary shape, of the container. The adjustment made

  between the two pieces is more or less tight.

  During the third operation, the probe of an ultrasound generator is applied in contact with the dispensing tip. It is known that the best results are obtained when the probe is machined to receive

  a large part of the dispensing tip

  tion. The fourth operation is to turn on the ultrasound generator. The ultrasonic waves thus produced are transmitted by conduction of the probe to the

  container passing through the dispensing tip. Inter-

  face formed between the surface of the dispensing nozzle and the adjacent inner surface of the neck of the container opposes resistance to ultrasonic waves. This resistance

  causes a heating of the interface.

  The dispensing tip and the container may be made of any one of a large number of synthetic thermoplastics. In an application 5.

  particular, the dispensing tip is injection molded

  homopolymer of high density polyethylene (0.955 g / cm3), with the generic name of polyolefin. The material actually used is produced by Gulf Oil Corporation and can be identified by product reference "9114". Its melt index is 18.0, this melt index being defined as the quantity in grams of a thermoplastic resin that can be forced through a

  orifice of 2.095 mm, under a force of 21.2 N, at a temperature of

  190WC, for 10 minutes. The melting point of this material is 190WC, this value being lower than

  the temperature that can be produced at the interface. Reconciliation

  It is blown into high density polyethylene homopolymer (0.957 g / cm3), with the generic name polyolefin. The material actually used is produced by

  Gulf Oil Corporation and is identified by the reference

  product code "9412". Its fractional melting index is 0.24 and its melting point is 1770C. Since the container melts at a temperature lower than that of the dispensing tip, it melts in the adjacent surface

the dispensing tip.

  A test makes it easy to determine for how many milliseconds the ultrasonic generator is to be operated to produce enough heat to partially soften and melt adjacent surfaces to weld them together, or to fuse one with the other. other adjacent surfaces without

  however, deteriorate the structure of the respective elements.

  The fifth operation is to stop the ultrasound generator after the base of the dispensing tip has been welded to the neck of the container. After this stop, the probe of the ultrasound generator is released from

the dispensing tip.

  The sixth operation is to put a removable cap on the container to protect

the dispensing tip.

  Figure 2 shows a container 10 forming part of a dispenser. This container comprises a neck 12 6. which has external threads 14. A nozzle 16, connected to a source of pressurized fluid by a conduit 18, discharges a fluid inside the container 10. When the discharged fluid is part of the family of cyanoacrylate type adhesives, only a small volume of this fluid (indicated by the numeral 20) is discharged into the container. After the fluid has been introduced into the container 10, the base 24 of the dispensing tip 22 is

  inserted in the neck 12, as shown in Figure 3.

  This base 24 is cylindrical and hollow and ends with an annular flange 26. The radial dimension of the base 24 corresponds to the internal radial dimension of the neck 12 so that a relatively tight fit is made between these two parts. The annular flange 26 is brought into contact on the end 28 of the neck delimiting the opening

of the last.

  On an assembly line or in a mass production system, it is possible to implement any of a number of devices known to those skilled in the art to pass the dispensing tip of a supply source to a position in which it is placed inside the neck 12 of the container 10. A probe 30 of an ultrasound generator 32 is

  brought into contact with the part of the nozzle 22 of

  The probe may have an internal recess 34 whose shape corresponds to that of the dispensing tip, so as to achieve between the two parts a good mechanical contact on

a large area.

  When the ultrasonic generator 32, for example of the 11800 type manufactured by Branson Sonic Power Company of Connecticut, is turned on,

  20 000 Hertz are transmitted electronically.

  and from the probe 30 to the container 10 via the dispensing tip 22. At the interface between the surface of the base 24 and the inner surface of the neck 12, the discontinuity in the composition of the transmission path opposes a certain resistance to the transmission of the ultrasonic waves. The resistance of the interface causes a heating and a rapid rise in the temperature of the surfaces forming this interface. By producing the ultrasonic waves for a predetermined time, it is possible to raise the temperature of the interface above the melting point of the material forming the dispensing tip and the container. The resulting fusion has the effect of welding to one another the dispensing nozzle and the container to achieve a seal and a mechanical lock between them. A consequence of the normal blow molding processes is that the inner surface of the neck

  presents high and low points randomly distributed

  tory. The high points, which are in contact with the surface of the base under greater pressure, melt the

  first and fluent so as to "fill" the low points.

  This function of the high points is designated, in practice, as a function of "energy orientation". The duration of the ultrasonic waves must obviously not be sufficient to

  cause a destructive fusion of the elements.

  Figure 5 shows the final assembly of the distribution

  scorer. During this final assembly, a cap 36 is lowered on the dispensing tip 22 and screwed onto the threads 14 of the neck 12. The dispenser is then ready to be shipped. In this embodiment of the dispenser, the dispensing nozzle is traversed by a channel avoiding any pressure elevation inside the container during

  attachment of the mouthpiece. This channel is hermetically sealed

  when attaching the cap as a result of entry into

  contact of the latter with the tip.

  Figure 6 shows schematically the operations

  variant of the method of welding a dispensing tip to a container. The dispensing nozzle is injection-molded of the material indicated above for the dispensing nozzle 22 and the container is blow-molded into the material indicated above for dispensing.

container 10.

  8. The first step is to inject a fluid into the neck of the container. In a general way,

  when a cyanoacrylate adhesive is injected, the recipe

  is only partially completed for the indi-

  previously. When the base of a dispensing nozzle is introduced into the neck of the container, the volume of the latter is reduced and the gas it contains is compressed so as to cause a corresponding rise in the internal pressure. The second operation is to reduce

  momentarily the volume of the container, of a value correspon-

  to the space occupied in the latter by the base of

  the dispensing tip inserted into said container.

  After the volume of the container has been reduced, the dispensing tip is brought into contact with the neck of the container and its base is introduced into this neck during the third operation. The fitting of the dispensing neck can be achieved by suspending the latter at

  a suitable stirrup or by the implementation of other mechanisms

nisms.

  After the insertion of the dispensing nozzle, the fourth operation is to release the walls of the container so that they can resume their normal shape and that the pressure inside the container can

  again become equal to the ambient pressure.

  During the fifth operation, a rotating stirrup is brought into contact with diametrically opposite tabs of the dispensing nozzle.

  at the same time as this commitment or after this commitment.

  means are used to prevent reconciliation

  just turn. When the stirrup is actuated during the sixth operation, the dispensing tip is rotated. Due to the frictional contact occurring

  between the base of the dispensing nozzle and the surface

  the neck of the container, a warm-up occurs

  during the relative rotation of the two elements. This heating

  localization causes a rapid rise in temperature.

  ture the surfaces in contact with the base of the dispensing tip and the neck. After a time that can be predetermined, the temperature rises above the melting point of the elements. The resulting partial melting has the effect of welding the surface of the base of the dispensing nozzle to the inner surface of the neck of the container,

  or to merge the adjoining surfaces

  Centes. As described above, the high points, randomly distributed inside the neck of the container, melt the first and fluent to the low points they fill. To prevent destructive melting of the surfaces in contact, the stirrup rotation is stopped at

  after a short time. A seal and a mechanical lock

  are made between these surfaces.

  At the end of the welding, the stirrup is removed and removed from the dispensing nozzle during the seventh operation. Alternatively, the rotation can be stopped by disengagement of the stirrup with or without simultaneous stop of the latter. The eighth operation is to prepare for marketing the filled dispenser by setting up

  on the latter a cap protecting the dispensing tip

thus fixed.

  Various apparatuses for carrying out the method shown schematically in FIG. 6 will now be described with reference to FIGS. 7, 8, 9 and 10. A container 40 is mounted by means of template elements 44 and 46 on a surface of work 42 so as not to be able to rotate. A nozzle 48, connected by a conduit 50 to a source of fluid, injects a quantity of fluid 52 into the container. When this fluid is a cyanoacrylate adhesive, the container is only partially filled, since a small amount of adhesive is used at each

  application and this adhesive is very expensive.

  To avoid an increase in the pressure inside the container 40 when attaching a dispensing nozzle 54, a plunger 56 is used to compress the container 40 or to exert a thrust on a wall of this container until the reduction in volume 10 is equivalent to the volume displaced by the base 58 of the dispensing nozzle when the latter is introduced into the neck 60 of the container. The diver 56 can be operated by

  a mechanical device or an electric coil S2.

  The dispensing nozzle 54 has two diametrically opposed tabs 64 and 66 projecting upwardly from an annular flange 68 which constitutes the apex of the base 58. A stirrup 70 projects downwardly from a rotary shaft 72. A mechanism, for example a belt 74 driven by a motor element and passing over a pulley 716 attached to the shaft, can be used to rotate the yoke. As shown particularly in Figure 9a, the yoke 70 may have two recesses 78 and 80 for engaging closely with the tabs 64 and 66, respectively. When starting the motor element (not shown) driving the belt 74, the rotational movement of the stirrup 70 is transmitted to the dispensing nozzle 54 so that the latter rotates at a speed of

  17,000 to 18,000 rpm. Since the recital

  40 is locked so that it can not be rotated by the template members 44 and 46, the friction occurring between the outer surface of the base 58 of the dispensing nozzle and the inner surface of the neck 60 causes heating. The latter has the effect of raising the temperature to a value greater than the melting point of the respective elements. When the latter begin to melt, it stops the rotation occurring between them by disengaging the stirrup of the dispensing tip, and let the elements cool. The fusion and the physical association resulting from the rotation have the effect of the formation of a weld which seals and a mechanical blocking between the nozzle 54 of distribution and the container 40. After the nozzle of distribution has been welded to the container, a

  cap 82 is lowered on the latter by means of a device

  mechanical device 84 well known to those skilled in the art. The cap encloses dispensing nozzle 54 and has internal members for locking on equivalent locking members 86 located around neck 60 of FIGS.

  container 10. The dispenser is then ready to be shipped.

  i1. It goes without saying that many modifications can be made to the apparatus described and shown without

depart from the scope of the invention.

12.

Claims (29)

  1. - Dispenser assembly apparatus   filled with liquid, each dispenser comprising a container   and a dispensing nozzle (22) which comprises a base (24), the apparatus being characterized in that it comprises a device (16) for injecting a certain amount of fluid into the container, a device for introducing the base of the dispensing tip into the neck of the container to make it come into contact with this neck, an ultrasonic wave generator and a device for transmitting the ultrasonic waves to the container via the dispensing nozzle and through the interface between the nozzle and the container, in order to heat the surfaces constituting this interface and to weld them one to the other.   2. Apparatus according to claim 1, characterized   in that the transmission device comprises a probe (30) which in particular has a cavity (34) intended to   receive a portion of the dispensing tip in order to to make a physical contact with her.   3. Apparatus according to claim 2, characterized   in that it comprises a device for moving the probe to make it come into contact with the nozzle of   distribution and move away from it.   4. - Method of assembling distributors   filled with liquid, each dispenser comprising a container   neck and a dispensing nozzle comprising a base, the method being characterized in that it consists in injecting a certain amount of fluid into the container, introducing the base of the dispensing tip into the neck of the container so that this base makes contact with the neck, to produce ultrasonic waves and to transmit these waves to the container via the dispensing nozzle and through the interface formed by the surfaces of the base and the neck in contact with the with each other, so as to heat these surfaces and to weld them to one another. 13.   5. - Process according to claim 4, characterized   risé in that it consists in moving the probe to bring it into contact with the dispensing tip and away from the latter. 6. - Dispenser assembly apparatus   filled with liquid, each dispenser comprising a container   pillar (40) with a neck (54) having a base (58), the apparatus being characterized in that it comprises a device (48) for injecting a certain quantity of fluid into the container with a neck, a device for introducing the base of the dispensing nozzle into the neck of the container in order to make it come into contact with this neck, and a device intended to rotate the base of the dispensing nozzle at the inside the neck of the container to cause heating and weld the base of the tip at the neck of the container.   7. Apparatus according to claim 6, characterized   risé in that it comprises a member (56) for momentarily reducing the volume of the container before the introduction of the base of the dispensing nozzle in the neck of this container.   8. - Apparatus according to one of claims 6   and 7, characterized in that it comprises members (44, 46) for preventing the container from rotating at the same time as the dispensing tip.   9. Apparatus according to claim 8, characterized   in that the device for rotating the base of the nozzle comprises elements (78, 80) intended to engage with the nozzle, radially relative to the axis of rotation of the latter, these elements of interlocking being arranged in particular radially and diametrically opposed by   relative to the axis of rotation of the dispensing nozzle.   10. Apparatus according to claim 9, characterized   characterized in that the member for reducing the volume of the container comprises a plunger (56) bearing against a wall of the container.   11. Apparatus according to claim 10, characterized   characterized in that the interlocking elements comprise a stirrup (70). 14.   12. Apparatus according to any one of the   1, 3, 6 and 11, characterized in that it comprises a device for fixing a cap on the container to   neck to protect the dispensing tip.   13. - Method of assembling distributors   filled with liquid, each dispenser comprising a container   neck and a dispensing nozzle which comprises a base, the method being characterized in that it consists in injecting a certain amount of fluid into the neck receptacle, introducing the base of the dispensing tip into the neck of the container to make it come into contact with this neck, and to rotate the base of the dispensing tip in the neck of the container to cause a   warm up and weld the base of the mouthpiece to the neck of the mouthpiece. tainer.   14. - Method according to claim 13, characterized   characterized in that it consists in temporarily reducing the volume of the container before the introduction of the base of the mouthpiece.   distribution in the neck of this container.   15. - Process according to claim 14, characterized   in that it consists in preventing the container from   turn at the same time as the dispensing tip.   16. - Method according to claim 15,   characterized in that the rotation operation is to engage with the dispensing tip, radially   relative to the axis of rotation of the latter.   17. - Method according to any one of the   4, 5, 13 and 16, characterized in that it consists in fixing a cap -on the neck container to protect the dispensing tip.   18. - Apparatus for welding together   adjacent surfaces of synthetic plastics   characterized in that it comprises a device for positioning a first element, a device for positioning a surface of a second element so that it is adjacent to a surface of the first element, and a device intended to produce a localized heating at the interface of the surfaces of the first and second elements, respectively, this 248251 5   15. heating up to a temperature sufficient to weld together the first and second elements by their respective adjacent surface.   19. Apparatus according to claim 18, characterized   characterized in that the device producing localized heating comprises an element intended to subject the surfaces   adjacent to the first and second elements sound.   20. Apparatus according to claim 19, characterized   characterized in that the first member is a container (10) having an opening and that the second member is a dispensing tip (22) mountable in the opening of the container, which member submits the adjacent surfaces to ultrasonic wave comprising a probe (30) and an ultrasonic wave source connected to said probe.   21. Apparatus according to claim 20, characterized   characterized in that the device for positioning the second member comprises members for mounting the dispensing tip so that it is in contact with the opening of the container. -   22. Apparatus according to claim 21, characterized   characterized in that the probe has a cavity (34) for receiving a portion of the dispensing tip and to be established a contact with her.   23. Apparatus according to claim 18, characterized   characterized in that the first and second elements are made   made of homopolymer of high density polyethylene.   24. Apparatus according to claim 18, characterized   in that the device intended to produce a heater   Locally located includes an element (70) adapted to move the second element relative to the first element against which it is rubbing to cause heating and   solder the second element to the first element.   25. Apparatus according to claim 24, characterized   characterized in that the first member is a container (40) having an opening and that the second member is a dispensing tip (54) mountable within the container opening, said member (70) for moving the second member comprising members for rotating the dispensing tip into the opening of the container and in relation to it.   26. Apparatus according to claim 25, characterized in that the device for positioning the first member comprises members (44, 46) preventing the first member from rotating together with the second member. 27. - Method for welding together   adjacent surfaces of synthetic plastics   characterized in that it consists of positioning a first element, positioning a surface of a second element so that it is adjacent to a surface of the first element and producing localized heating at the interface of the surfaces of the first element. and second elements, respectively, this heating reaching a temperature sufficient to weld together the first and second elements by their respective adjacent surfaces.   28. - Process according to claim 27, characterized   characterized in that producing a warm-up consists of subjecting the adjacent surfaces of the first and second   elements to ultrasonic waves.   29. - Process according to claim 27, characterized   characterized in that producing a warm-up consists in moving the second element relative to the first element against which it is rubbing in order to produce a heating and   to solder the second element to the first element.   30. - Process according to claim 29, characterized   characterized in that the first member is a container having an opening and in that the second member is a dispensing nozzle mountable in the opening of the container, moving the second member relative to the first member dispensing tip inside the opening of the container and by report to her.