GB2076335A

GB2076335A - Apparatus and method for sealing thermoplastic tips to containers

Info

Publication number: GB2076335A
Application number: GB8023770A
Authority: GB
Original assignee: Pacer Technology and Resources Inc
Current assignee: Pacer Technology and Resources Inc
Priority date: 1980-05-15
Filing date: 1980-07-21
Publication date: 1981-12-02
Also published as: DE3028081A1; JPS5747617A; FR2482515A1; IT1146991B; IT8049550A0

Abstract

Adjacent surfaces of man-made plastics elements, 0.9. a thermoplastic dispensing tip and a thermoplastic container of a dispenser are welded to one another by generating localized heat at the interface of the surfaces. After insertion of the base of a dispensing tip (22), Fig. 4, within the neck (12) of a filled container (10), ultrasonic vibrations may be transmitted by a probe (30) in contact with the dispensing tip (22) across the interfacing surfaces (54). of the base of the dispensing tip (22) base and the interior of the container neck (12). Alternatively, the base of a dispensing tip (54), Fig. 8, is inserted within a tight fitting neck of a filled container (40) simultaneous with or prior to relative rotational movement therebetween. The heat generated by frictional interference between the dispensing tip base and the interior surface of the neck as a result of the relative rotation therebetween raises the temperature of the interfacing surface of the dispensing tip base and container neck interior sufficiently to weld these surfaces to one another. To prevent pressure build-up in the container (40), a plunger (56) pushes in a wall thereof to compensate for the volume displacement caused by the insertion of the base (58) of the tip (54). <IMAGE>

Description

SPECIFICATION Apparatus and method for sealing thermoplastic tips to containers The present invention relates to an apparatus and method of welding adjacent surfaces of man-made plastics elements to one another and more particularly relates to an apparatus and a method for sealingly attaching thermoplastic dispensing tips to thermoplastic containers.

A multitude of liquid products are packaged in containers having dispensing tips attached thereto. A large number of these dispensers have the container and the dispensing tip manufactured from any one of a very large number of man-made thermoplastic materials.

For many of these materials, adhesive means are not available to effect a seal between the dispensing tip and the container. Accordingly, reliance for a seal must reside in the mechanical attachment therebetween. See for example United States Patent No. 4,138,040.

For many fluids dispensed from such dispensers, the mechanical seal serves its purpose very well. For fluids of very low viscosity and/or fluids which readily creep by capillary action, a mechanical seal is not always adequate. The resulting leakage problems are exacerbated whtn the dispensers are subjected to substantial temperature and pressure changes such as occur during shipment in an unpressurized hold of a transport aircraft.

It has now been found that the present invention enables the provision of: (i) a method for welding a thermoplastic dispensing tip to a thermoplastic container of a dispenser; (ii) a method for generating heat at the interface between a dispensing tip and a container of a dispenser to effect a weld therebetween; (iii) a method for effecting relative rotation between a dispensing tip and a container of a dispenser to generate sufficient heat to weld the dispensing tip to a container; (iv) a method usable in a mass production assembly line for sealingly attaching dispenser tips to filled containers of a dispenser.

(v) a method for welding two elements to one another by generating heat localized at the interface between the elements; (vi) an apparatus for sealingly mating a dispensing tip to a container of a dispenser with ultrasound; (vii) an apparatus for effecting relative rotation between a dispensing tip and a container upon mating thereof; (viii) an apparatus for filling, assembling and sealing thermoplastic dispensers; and (ix) an apparatus for welding two elements to one another by generating heat localized at the interface therebetween.

According to one aspect of the present invention there is provided an apparatus for welding adjacent surfaces of man-made plastic elements to one another, said apparatus comprising in combination: (a) locating means for locating a first one of the elements; (b) positioning means for positioning a surface of a second one of the elements adjacent a surface of the first element; and (c) heat generating means for generating localized heat at and across the interface of the first and second surfaces of the first and second elements, respectively, of a temperature sufficient to weld the first element to the second element at their respective adjacent surfaces.

In one embodiment, the heat generating means comprises ultrasonic wave subjecting means for subjecting the adjacent surfaces of the first and second elements to ultrasonic waves, and preferably the first element is an apertured container, the second element is a dispensing tip mountable within the aperture of the container, and the ultrasonic wave subjecting means comprises a probe (which conveniently includes a cavity for receiving at least a part of the dispensing tip) and a source of ultrasonic waves operatively connected thereto.

In another embodiment, the heat generating means includes movement means for moving the second element relative to and in frictional contact with the first element to produce heat and thereby weld the second element to the first element. Preferably, the first element is an apertured container, the second element is a dispensing tip mountable within the aperture of the container, and the movement means comprises rotation means for rotating the dispensing tip relative to and within the aperture of the container.

In another aspect the present invention provides a method of welding adjacent surfaces of man-made plastics elements to one another which comprises the steps of: (a) locating a first one of the elements; (b) positioning a surface of a second one of the elements adjacent a surface of the first element; and (c) generating localized heat at and across the interface of the first and second surfaces of the first and second elements, respectively, of a temperature sufficient to weld the first element to the second element at their respective adjacent surfaces.

In further aspects, the present invention provides: (A) An apparatus for assembling liquid filled dispensers, each of which dispensers includes a necked container and a dispensing tip having a base, said apparatus comprising in combination: (a) injection means for injecting a quantity of fluid into the necked container; (b) insertion means for inserting the base of the dispensing tip into contacting relationship with the neck of the necked container; (c) a generator of ultrasonic waves; and (d) transmitting means for transmitting the ultrasonic waves through the dispensing tip across the interface into the necked container to generate heat at the interfacing surfaces and thereby weld the interfacing surfaces to one another.

(B) A method of assembling liquid filled dispensers, each of which dispenser includes a necked container and a dispensing tip having a base, which comprises the steps of: (a) injecting a quantity of fluid into the necked container; (b) inserting the base of the dispensing tip into contacting relationship with the neck of the necked container; (c) generating ultrasonic waves; and (d) transmitting the ultrasonic waves through the dispensing tip across the interface into the necked container to generate heat at the interfacing surfaces and thereby weld the interfacing surfaces to one another.

(C) An apparatus for assembling liquid filled dispensers, each of which dispensers includes a necked container and a dispensing tip having a base, said apparatus comprising in combination: (a) injection means for injecting a quantity of fluid into the necked container; (b) insertion means for inserting the base of the dispensing tip into contacting relationship with the neck of the necked container; and (c) rotation means for rotating the base of the dispensing tip within the neck of the necked container to generate heat and thereby weld the base of the dispensing tip to the neck of the necked container.

(D) A method of assembling liquid filled dispensers, each of which dispensers includes a necked container and a dispensing tip having a base, which comprises the steps of: (a) injecting a quantity of fluid into the necked container; (b) inserting the base of the dispensing tip into contacting relationship with the neck of the necked container; and (c) rotating the base of the dispensing tip within the neck of the necked container to generate heat and thereby weld the base of the dispensing tip to the neck of the neck container.

The present invention is further illustrated with reference to-the accompanying drawings, in which: Figure 1 recites a plurality of steps defining a method of the present invention; Figures 2, 3, 4 and 5 illustrate an appa ratus for carrying out the various steps of the method recited in Fig. 1; Figure 6 recites a plurality of steps of a variant of a method of the present invention; and Figures 7, 8, 9 and 10 illustrate apparatus for carrying out the various steps of the variant method recited in Fig. 6.

Many fluids are adequately well retained within dispensers which have the base of a dispensing tip interference fitted within the neck of a container housing the fluid. This is particularly true where the viscosity of the fluid is relatively high or where the manufacturing economics permits high tolerance interfacing surfaces. In more sophisticated dispensers, both the neck of the container and the dispensing tip have variously formed annular convolutions to effect a relatively high pressure (kilograms per square metre or pounds per square inch) mechanical seal therebetween. For most low viscosity fluids or those fluids which creep substantially by capillary action, most mechanical seals usable on mass produced dispensers inherently contain too many imperfections to develop or establish an adequate seal.This problem is particularly exacerbated when the temperature and pressure within the container may vary substantially such as during transport of the dispensers in an unpressurized hold of an aircraft.

In place of or supplemental to mechanical seals, adhesives may be employed, depending upon the type and nature of the fluid to be dispensed and the material of the dispenser itself. Such adhesives may not, however, be used if the fluid will react with the adhesive or if the adhesive will tend to contaminate the fluid.

The storage and dispensation of a member of the family of cyanoacrylate adhesives presents a particularly difficult problem not yet solved by the prior art. One of the attributes of a cyanoacrylate adhesive is that it will "creep" and thereby is capable of adhering mating surfaces to one another which are inaccessible to other adhesives. This same attribute creates a very difficult problem to construct a dispenser for the cyanoacrylate adhesive which will not leak under forseeable circumstances.

To be commercially competitive, cyanoacrylate adhesives and dispensers therefor must be manufacturable by mass production tenchiques which limits the degree of tolerance which can be demanded of the various components. The necessarily allowable tolerances preclude the possibility of effectively mechanically sealing a dispensing tip to a cyanoacrylate filled container. The use of an adhesive to effect a seal is not an available solution since contact with the adhesive will contaminate the cyanoacrylate adhesive. Such contamination will cause partial curing and blockage of the dispenser tip or possibly preclude curing after dispensation, any of which results are commercially unacceptable.

Referring to Fig. 1, there is recited a method for effecting a sealed attachment of a dispensing tip to a container. This method requires no coating of mating surfaces with an adhesive or sealant. The first step includes injecting a fluid, such as one of the family of cyanoacrylate adhesives, into the container through and out of contact with the interior surface of the container neck. Because these adhesives are relatively expensive per unit weight and a minute quantity is used at each application, the container is usually only partially filled.

In step two, the base of the dispensing tip is inserted into a matingly configured neck of the container. The fit therebetween is more or less of an interference fit type.

In step three, the probe of an ultrasonic generator is brought into physical contact with the dispensing tip. It has been learried that the best results are obtained if the probe is machined to matingly receive a substantial part of the dispensing tip.

Step four includes actuating the ultrasonic generator. The generated ultrasonic waves are conductively transmitted from the probe through the dispensing tip to the container.

The interface between the adjacent surfaces of the dispensing tip and the interior surface of the necked portion of the container presents a resistance to the ultrasonic waves. This resistance generates heat at the interface.

The dispensing tip and container may be made of any one of many man-made thermoplastics. In a particular application, the dispensing tip is injection moulded of a high density (0.955 gms/cc) polyethylene homopolymer material generically termed a polyoelfin. The material actually used is manufactured by the Gulf Oil Corporation and is identifiable as product number 9114. It has a melt index of 18.0; the melt index is defined as the amount in grams of a thermoplastic resin which can be forced through a 0.0825" ("'2.0955mm) orifice when subjected to 2160 grams of force during ten (10) minutes at a temperature of 190 C. The melting point of this material is 375 F (#190.5'C), which is less than the temperature capable of being generated at the interface.The container is blow moulded of a high density (0.957 gms/cc) polyethylene homopolymer material generically termed polyolefin. The material actually used is manufactured by the Gulf Oil Corporation and is identifiable as product number 9412. It has fractional melt index of 0.24 and a melting point of 350 F (#1 76.6'C). As the container melts at a lower temperature than the dispensing tip, it will melt into the adjacent surface of the dispensing tip.

Through experimentation it can be readily determined how many milliseconds the ultrasonic generator must be actuated to produce heat of a sufficient temperature to soften and partially to melt the interfacing surfaces to obtain a weld therebetween, or to fuse the adjacent surfaces to one another, and yet not structurally damage the respective components.

Step five contemplates de-energizing of the ultrasonic generator subsequent to the welding of the dispensing tip base to the neck of the container. Following de-energization, the probe of the ultrasonic generator is disengaged from the dispensing tip.

Step six includes adding a removable cap to the container to protect the dispensing tip.

Referring now to Fig. 2, there is shown a container 10 forming a part of a dispenser.

The container 10 includes a neck 12 having threads 14 externally located thereabout. A nozzle 16, attached to a source of fluid under pressure through a conduit 18 discharges fluid into the container 10. When the fluid discharged is a fluid such as a member of the family of cyanoacrylate adhesives, only a small volume of fluid (represented by numeral 20 and the chain lines) is discharged into the container.

After discharge of fluid into the container 10, the base 24 of a dispensing tip 22, as illustrated in Fig. 3, is inserted within the neck 12. The base 24 is 'cylindrical and hollow and is terminated by an annular flange 26. The radial dimension of-the base 24 is commensurate with the internal radial dimension of the neck 12 such that a reasonably tight mating fit therebetween occurs. The annular flange 26 is brought to rest upon the end 28 of the neck 12 defining the opening thereinto.

On an assembly-line or as part of a mass production system, any one of many means known to those skilled in the art may be employed to transport the dispensing tip 22 from a source of supply into position within the neck 12 of the container 10.

A probe 30 of an ultrasonic generator 32 is brought into contacting relationship with the protruding part of the dispensing tip 22, as is shown in Fig. 4. The probe may include an internal cavity 34 duplicative of the configuration of the dispensing tip to obtain good large surface mechanical contact therebetween.

Upon energization of the ultrasonic generator 32, such as Model 800 manufactured by Branson Sonic Power Company of Connecticut, ultrasonic waves of a frequency of 20,000 hertz are transmitted from the probe 30 through the dispensing tip 22 and into the container 10. At the interface of the surface of the base 24 and the interior surface of the neck 12, resistance to transmission of the ultrasonic waves will occur because of the discontinuity in composition of the transmission path. The resistance at the interface will generate heat and a rapid temperature rise at the interfacing surfaces. By generating the ultrasonic waves for a predeterminable duration, the temperature rise at the interface will be above that of the melting point of the material forming the dispensing tip and the container.The resulting melting will cause the dispenser tip and the container to be welded to one another to effect a seal and mechanical lock therebetween. By normal blow moulding processes, the interior surface of the neck will have random high and low spots. The high spots, being in contact with the surface of the base under more pressure will melt first and flow as a "filler" into the low spots. This function of the high spots is referred to in the art as an "energy director". Necessarily, the duration of the ultrasonic waves must not continue for long enough to cause destructive melting of the components.

The final assembly of the dispenser is illustrated in Fig. 5. During this final assembly, a cap 36 is brought down over the dispensing tip 22 and into threaded engagement with the threads 14 on the neck 12. The dispenser is now ready for shipment.

In this embodiment of the dispenser, a passageway exists through the dispensing tip and this will alleviate a pressure rise within the container on attachment of the dispensing tip. The passageway is sealed upon attachment of the cap as a result of engagement therewith.

The steps of a variant method for welding a dispensing tip to a container are recited in Fig. 6. The dispensing tip is injection moulded of the material described above with respect to the dispensing tip 24 and the container is blow moulded of the material described above with respect to container 10.

The first step contemplates the injection of fluid into the necked container. Usually, when a cyanoacrylate adhesive is injected, the container is only partially filled for the reasons stated above.

When the base of a dispensing tip is inserted within the neck of a container, the volume of the container will be reduced and the gas therein will be compressed with a commensurate internal pressure rise. Step two contemplates temporarily reducing the volume of the container by an amount equivalent to the space within the container taken up by the base of the dispensing tip inserted therein.

Upon reduction of the volume of the container, the dispensing tip is brought, in step three, into contact with and the base thereof is inserted within the neck of the container.

Engagement of the dispensing tip may be by suspension from a rotatable yoke or by other mechanisms After insertion of the dispensing tip, step four contemplates releasing the walls of the container to allow them to assume their normal configuration, and the pressure within the container will resume ambient pressure.

In step five, a rotatable yoke is brought into engagement with diametrically opposed lugs on the dispensing tip. Prior to; subsequent to or commensurate with engagement of the lugs, means are employed to prevent rotation of the container. On energization of the yoke in step six, -the dispensing tip will be caused to be rotated. Because of frictional engagement intermediate the base of the dispensing tip and the interior surface of the neck of the container, heat will be generated upon rotation therebetween. This localized heat will result in a rapid temperature rise of the interfacing surfaces of the dispenser tip base and the neck. At a predeterminable time, the temperature will rise above that of the melting point of the components.The resulting partial melting will weld the base of the dispensing - tip base surface to the interior surface of the neck of the container; or, fuse the adjacent surfaces to one another. As described above, the random high spots within the neck of the container will melt first and flow to the low spots as a filler. To prevent destructive melting of the interfacing surfaces, rotation of the yoke is terminated after a brief duration.

Thereby, a seal and mechanical interlock therebetween is achieved.

On completion of the weld; the yoke is withdrawn from contact with the dispensing tip in step seven. Alternatively, cessation of rotation may be effected by disengaging the yoke with or without simultaneous cessation of the yoke.

The eighth step is preparing the filled dispenser ready for market and contemplates the addition of a cap to protect the attached dispensing tip.

Various apparatus for effecting the process recited in Fig. 6 will be described with serial reference to Figs. 7, 8, 9 and 10. A container 40 is nonrotatably supported upon a work surface 42 by means of jigs 44 and 46. A nozzle 48, connected through a conduit 50 to a source of fluid, injects a quantity of fluid 52 into the container 40. When the fluid is a cyanoacrylate adhesive, the container is only partially filled as a minute amount of the adhesive is used at each application and the adhesive is quite expensive.

To prevent a pressure buildup within the container 40 on attachment of a sealed dispenser tip 54, a plunger 56 is employed to squeeze the container 40 or to push in a wall thereof until the reduction in volume is equivalent to the volume equivalent to that displaced by the base 58 of the dispensing tip 54 upon insertion within the neck 60 of the container. The plunger 56 may be actuated by mechanical means or by an electrically energized solenoid 62.

The dispensing tip 54 includes a pair of diametrically oriented lugs 64 and 66 extending upwardly form an annular flange 68 defining the top of the base 58. A yoke 70 depends from a rotatable shaft 72. Means, such as a belt 74 driven by motive means and an engaging pulley 76 attached to the shaft, may be employed to effect rotation of the yoke. As particularly illustrated in Fig. 9a, the yoke 70 may include a pair of recesses 78 and 80 for respective mating engagement with the lugs 64 and 66. Upon energization of the motive means (not illustrated) and thereby the driving belt 74, the rotary motion of the yoke 70 is translated to the dispensing tip 54 to spin the dispensing tip at a speed of, for example 17,000-18,000 rpm.Since the container 40 is restrained from rotation by the jigs 44 and 46, friction intermediate the external surface of the base 58 of the dispensing tip 54 and the internal surface of the neck 60 will generate heat. The resulting temperature rise will exceed the melting point of the respective components. When these components begin to melt, rotation therebetween is stopped by disengaging the yoke 70 from the dispensing tip 54 and the components are permitted to cool. The melting and physical interference which occurred during rotation will produce a weld therebetween to seal and mechanically lock the dispensing tip 54 to the container 40.

After the dispensing tip has been welded to the container, a cap 82 is lowered onto the container by mechanical means 84 well known to those skilled in the art. The cap encapsulates the dispensing tip 54 and includes internally mounted means for lockingly engaging with equivalent locking means 86 disposed about the neck 60 of the container 10. The dispenser is now ready for shipment.

Claims

1. An apparatus for assembling liquid filled dispensers, each of which dispensers includes a necked container and a dispensing tip having a base, said apparatus comprising in combination: (a) injection means for injecting a quantity of fluid into the necked container; (b) insertion means for inserting the base of the dispensing tip into contacting relationship with the neck of the necked container; (c) a generator of ultrasonic waves; and (d) transmitting means for transmitting the ultrasonic waves through the dispensing tip across the interface into the necked container to generate heat at the interfacing surfaces and thereby weld the interfacing surfaces to one another.

2. An apparatus as claimed in Claim 1 further comprising means for attaching a cap to the necked container to protect the dispensing tip.

3. An apparatus as claimed in Claim 1 or Claim 2 wherein the transmitting means comprises a probe.

4. An apparatus as claimed in Claim 3 wherein the probe includes a cavity for receiving at least a part of the dispensing tip to establish physical contact therebetween.

5. An apparatus as claimed in Claim 3 or Claim 4 which further comprises transporting means for transporting the probe into and out of contact with the dispensing tip.

6. An apparatus as claimed in any of Claims 1 to 5 which further comprises means for attaching a cap to the necked container to protect the dispensing tip.

7. An apparatus for assembling liquid filled dispensers substantially as herein described with reference to, and as shown in Figs. 2, 3, 4 and 5 of the accompanying drawings.

8. A method of assembling liquid filled dispensers, each of which dispensers includes a necked container and a dispensing tip having a base, which comprises the steps of: (a) injecting a quantity of fluid into the necked container; (b) inserting the base of the dispensing tip into contacting relationship with the neck of the necked container; (c) generating ultrasonic waves; and (d) transmitting the ultrasonic waves through the dispensing tip across the interface into the necked container to generate heat at the interfacing surfaces and thereby weld the interfacing surfaces to one another.

9. A method as claimed in Claim 8 which further comprises the step of attaching a cap to the necked container to protect the dispensing tip.

10. A method as claimed in Claim 8 or 9 which further includes the step of transporting the probe into and out of contact with the dispensing tip.

11. A method as claimed in Claim 8 substantially as herein described with reference to and as shown in Figs. 1 to 5 of the accompanying drawings.

12. An apparatus for assembling liquid filled dispensers, each of which dispensers includes a necked container and a dispensing tip having a base, said apparatus comprising in combination: (a) injection means for injecting a quantity of fluid into the necked container; (b) insertion means for inserting the base of the dispensing tip into contacting relationship with the neck of the necked container; and (c) rotation means for rotating the base of the dispensing tip within the neck of the necked container to generate heat and thereby weld the base of the dispensing tip to the neck of the necked container.

13. An apparatus as claimed in Claim 12 which further comprises means for attaching a cap to the necked container to protect the dispensing tip.

14. An apparatus as claimed in Claim 12 or Claim 13 which further comprises means for preventing rotation of the necked container during rotation of the dispensing tip.

15. An apparatus as claimed in any of Claims 12 to 14 wherein the rotation means includes engaging means for interferingly en gaging the dispensing tip on a radial to the axis of rotation of the dispensing tip.

16. An apparatus as claimed in Claim 15 wherein the engaging means are diametrically opposed and radial to the axis of rotation of the dispensing means.

17. An apparatus as claimed in Claim 15 or Claim 16 wherein the engaging means includes a yoke.

18. An apparatus as claimed in any of Claims 12 to 17 which further comprises reducing means for temporarily reducing the volume of the necked container prior to insertion of the base of the dispensing tip within the neck of the necked container.

19. A method of assembling liquid filled dispensers substantially as described with reference to Figs. 6 to 10 of the drawings.

19. Anapparatus as claimed in Claim 18 wherein the reducing means comprises a plunger bearing against a wall of the necked container.

20. An apparatus for assembling liquid filled dispensers substantially as herein described with reference to, and as shown in Figs. 7, 8, 9 and 10 of the accompanying drawings.

21. A method of assembling liquid filled dispensers, each of which dispensers includes a necked container and a dispensing tip having a base, which comprises the steps of: (a) injecting a quantity of fluid into the necked container; (b) inserting the base of the dispensing tip into contacting relationship with the neck of the necked container; and (c) rotating the base of the dispensing tip within the neck of the necked container to generate heat and thereby weld the base of the dispensing tip to the neck of the neck container.

22. A method as claimed in Claim 21 which further comprises the step of attaching a cap to the necked container to protect the dispensing tip.

23. A method as claimed in Claim 21 or Claim 22 which further comprises the step of preventing rotation of the necked container during rotation of the dispensing tip.

24. A method as claimed in any of Claims 21 to 23 wherein the rotating step includes the step of interferingly engaging the dispensing tip on a radial to the axis of rotation of the dispensing tip.

25. A method as claimed in any of Claims 21 to 24 which further comprises the step of temporarily reducing the volume of the necked container prior to the insertion of the base of the dispensing tip within the neck of the necked container.

26. A method as claimed in Claim 21 substantially as herein described with reference to, and as shown in, Figs. 6 to 10 of the accompanying drawings.

27. An apparatus for welding adjacent surfaces of man-made plastics elements to one another, said apparatus comprising in combination: (a) locating means for locating a first one of the elements; (b) positioning means for positioning a surface of a second one of the elements adjacent a surface of the first element; and (c) heat generating means for generating localized heat at and across the interface of the first and second surfaces of the first and second elements, respectively, of a temperature sufficient to weld the first element to the second element at their respective adjacent surfaces.

28. An apparatus as claimed in Claim 27 wherein the heat generating means comprises,,, ultrasonic wave subjecting means for subjecting the adjacent surfaces of the first and second elements to ultrasonic waves.

29. An apparatus as claimed in Claim 28 wherein the first element is an apertured container, the second element is a dispensing tip mountable within the aperture of the con tainer, and, the ultrasonic wave subjecting means comprises a probe and a source of ultrasonic waves operatively connected to said probe.

30. An apparatus as claimed in Claim 29 wherein the positioning means comprises mounting means for mounting the dispensirig tip in contacting relationship with the aperture of the container.

31. An apparatus as claimed in Claim 29 or Claim 30 wherein the said probe includes a cavity for receiving in contacting relationship at least a part of the dispensing tip.

32. An apparatus as claimed in any of Claims 27 to 31 wherein the first and second elements are composed of high density polyethylene homopolymers.

33. An apparatus as claimed in Claim 27 wherein the heat generating means includes movement means for moving the second element relative to and in frictional contact with the first element to produce heat and thereby weld the second element to the first element.

34. An apparatus as claimed in Claim 33 wherein the first element i#s an apertured container, the second element is a dispensing tip mountable within the aperture of the container, and the movement means comprises rotation means for rotating the dispensing tip relative to and within the aperture of the container.

35. An apparatus as claimed in Claim 33 or Claim 34 wherein the locating means includes means for precluding rotation of the first element during rotation of the second element.

36. A method of welding adjacent surfaces of man-made plastics elements to one another, which comprises the steps of: (a) locating a first one of the elements; (b) positioning a surface of a second one of the elements adjacent a surface of the first element; and (c) generating localized heat at and across the interface of the first and second surfaces of the first and second elements, respectively, of a temperature sufficient to weld the first element to the second element at their respective adjacent surfaces.

CLAIMS (1st Sep 1981)

1. An apparatus for assembling liquid filled dispensers, each of which dispensers includes a necked container and a dispensing tip having a base, said apparatus comprising in combination: (a) injection means for injecting a quantity of fluid into the necked container; (b) insertion means for inserting the base of the dispensing tip into contacting relationship with the neck of the necked container; (c) a generator of ultrasonic waves; (d) a probe, including a cavity for receiving a part of the dispensing tip to establish physical contact therebetween, for transmitting the ultrasonic waves through the dispensing tip across the interface into the necked container to generate heat at the interfacing surfaces and thereby weld the interfacing surfaces to one another; and (e) transporting means for transporting said probe into and out of contact with the dispensing tip.

2. An apparatus for assembling liquid filled dispensers substantially as described with reference to, or as shown in Figs. 2, 3, 4, and 5 of the drawings.

3. A method of assembling liquid filled dispensers, each of which dispensers includes a necked container and a dispensing tip having a base which comprises the steps of: (a) injecting a quantity of fluid into the necked container; (b) inserting the base of the dispensing tip into contacting relationship with the neck of the necked container; (c) generating ultrasonic waves; (d) transmitting the ultrasonic waves through the dispensing tip across the interface into the necked container to generate heat at the interfacing surfaces and thereby weld the interfacing surfaces to one another; and (e) transporting the probe into and out of contact with the dispensing tip.

4. A method of assembling liquid filled dispensers described with reference to Figs. 1 to 5 of the drawings.

5. An apparatus for assembling liquid filled dispensers, each of which dispensers includes a necked container and a dispensing tip having a base, said apparatus comprising in combination: (a) injection means for injecting a quantity of fluid into the necked container; (b) insertion means for inserting the base of the dispensing tip into contacting relationship with the neck of the necked container; (c) reducing means for temporarily reducing the volume of the necked container prior to insertion of the base of the dispensing tip within the neck of the necked container; and (d) rotation means for rotating the base of the dispensing tip within the neck of the necked container to generate heat and thereby weld the base of the dispensing tip to the neck of the necked container.

6. An apparatus according to Claim 5 including means for preventing rotation of the necked container during rotation of the dispensing tip.

7. An apparatus according to Claim 6, wherein the rotation means includes engaging means for interferingly engaging the dispensing tip on a radial to the axis of rotation of the dispensing tip.

8. An apparatus according to Claim 7, wherein the engaging means are diametrically opposed and radial to the axis of rotation of the' dispensing means.

9. An apparatus according to any of Claims 5 to 8 wherein the reducing means comprises a plunger bearing against a wall of the necked container.

10. An apparatus according to Claim 9, wherein the engaging means includes a yoke.

11. An apparatus according to Claim 10, which further comprises attaching means for attaching a cap to the necked container to protect the dispensing tip.

12. An apparatus for assembling liquid filled dispensers, substantially as described with reference to, or as shown in Figs. 7, 8, 9 and 10 of the drawings.

13. A method of assembling liquid filled dispensers, each of which dispensers includes a necked container and a dispensing tip having a base which comprises the steps of: (a) injecting a quantity of fluid into the necked container; (b) inserting the base of the dispensing tip into contacting relationship with the neck of the necked container; (c) temporarily reducing the volume of the necked container prior to the insertion of the base of the dispensing tip within the neck of the necked container; and (d) rotating the base of the dispensing tip within the neck of the necked container to generate heat and thereby weld the base of the dispensing tip to the neck of the necked container.

14. A method according to Claim 13, which further comprises the step of preventing rotation of the necked container during rotation of the dispensing tip.

15. A method according to Claim 13 or 14, wherein the rotating step includes the step of interferingly engaging the dispensing tip on a radial to the axis of rotation of the dispensing tip.

16. A method according to Claim 13, 14 or 15, which further comprises the step of attaching a cap to the necked container to protect the dispensing tip.

17. An apparatus as claimed in any of Claims 1, or 5 to 11 wherein the container and the dispensing tip are composed of high density polyethylene homopolymers.

18. A method according to any of Claims 3, and 13 to 16, wherein the container and the dispensing tip are composed of high den sity polyethylene homopolymers.