GB2118895A

GB2118895A - Oscillatory bonding

Info

Publication number: GB2118895A
Application number: GB08310967A
Authority: GB
Inventors: Laughlin Donal N Mac; Vincent E Fortuna
Original assignee: Cosden Technology Inc
Current assignee: Cosden Technology Inc
Priority date: 1982-04-23
Filing date: 1983-04-22
Publication date: 1983-11-09
Also published as: SE8302214D0; DE3314457A1; GB8310967D0; GB2118895B; NL8301424A; SE8302214L; FR2525524A1

Abstract

Methods and apparatus are disclosed for the bonding together of two similarly shaped articles of similar thermoplastic material utilizing oscillatory motion between the two articles to generate frictional heat therein sufficient to form an hermetic seal therebetween. <IMAGE>

Description

SPECIFICATION Apparatus and methods for oscillatory bonding The present invention relates generally to the bonding together of two similarly shaped portions of thermoplastic articles and more particularly involves friction welding of upper and lower container sections to provide a single hermetically welded container.

The prior art discloses a method of welding container sections together to form a single container, which method is directed to cylindrically shaped thermoplastic containers which are rotated at high speeds against each other to generate by friction the heat necessary to bond the two sections together. This prior art method is commonly referred to as spin-welding and is disclosed in such patents as U.S.

3,297,504, U.S. Reissue 29,448, and U.S.

3,499,068.

While the prior art method of spin-welding is advantageous over such methods as chemical bonding, cementing, and thermal bonding by means such as laser, electron beam, radio wave, and electrical means, it offers disadvantage in that it is restricted to cylindrical joints. Obviously two non-cylindrical container sections could not be successfully spin-welded because of their lack of surfaces which would maintain contact during relative rotary motion between them.

The present invention overcomes the disadvantage of rotary spin-welding by providing methods and apparatus for friction welding thermoplastic containers having non-cylindrical joinder sections as well as being applicable also to cylindrical sections. The present invention utilizes oscillatory motion, rather than rotary motion, between the two sections to be joined to provide the friction for generating the heat of bonding between the two sections.

According to the present invention there is provided apparatus for friction welding two thermoplastic articles together, said apparatus comprising: a first holder adapted for clamping engagement of a first article to be welded, comprising first clamping means and a receptacle for receiving said first article; said first holder being mounted on a tool adapted for axial sliding movement; said tool being mounted slidably on a first base module; oscillator means connected to said first tool and said first base module and arranged to oscillate said first tool axially with respect to said first module; a second holder mounted on a second base module and adapted for clamping engagement of a second article to be welded to said first article, said second holder being axially aligned with said first holder in close proximity thereto, and comprising a receptacle for receiving said second article, and second clamping means for holding said second article in said second holder; and, means for moving said first and second holders back-and-forth between an article-engaged position and an articledisengaged position.

The present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:~ Figures 1-3 are cross-sectional side views of three different types of container joints which can be joined utilizing the present invention; Figure 4 is a partial side view of an oscillatory welding apparatus for low-frequency welding; Figure 5 is a schematic view of a rotary air joint for use with the apparatus of Figure 4; Figure 6 is a partial side view of an oscillatory welding apparatus for high-frequency welding: Figure 7 is a schematic diagram of the rotary joint to provide air and electrical power to the apparatus of Figure 6; Figure 8 is a schematic top view of the rotary infeed and exit system for the oscillatory welding apparatus.

The present invention is a modification and improvement over the apparatus disclosed in U.S.

Patents 3,499,068 and Re 29,448, which patents are herein incorporated by reference in their entirety. For ease of description the present invention will be described with reference to only one station of a multi-station system such as the multi-station systems disclosed in the abovementioned incorporated patents. Except for the modifications disclosed with respect to the single described station, the remainder of the containerforming system of this invention is substantially the same as that of the incorporated patents.

Referring now to Figure 4, the single station 10 of the bonding system 11 is shown in side elevational view. The single station is typical of the other stations contained on the multiple station rotary system. The station comprises an upper carrier assembly 12 mounted by rollers and an upper cam head 13. The lower carrier assembly 14 is mounted in a lower cam assembly 15 by roller follower means 1 6. Upper assembly 12 is mounted in cam head 13 by roller follower 17.

Upper cam head 13 generally comprises a substantially circular vertical cam plate 18 having formed therein a peripheral cam groove 19. Cam groove 19 passes circumferentially around cam head 13 and is arranged to receive roller follower 17 1 7 in relatively close-fitting engagement therein.

Cam channel 19 has vertical fluctuations such as shown at 20 for providing controlled vertical movement of carrier assembly 12 as it rotates about cam head 13.

Likewise the lower cam assembly contains a peripheral cam channel 21 encircling the generally circular shaped cam head and arranged to receive cam follower 16 rotatably therein. Cam channel 21 likewise has vertical fluctuations for providing vertical movement of lower assembly 14 with respect to upper assembly 1 2.

Lower assembly 14 generally comprises a vertical spindle mount 22 to which is attached a lower tool 23 for receiving and tightly clamping the lower portion of the container to be bonded.

Tool 23 preferably has an internal cavity facing upward shaped generally to conform to the shape of the lower container portion to be bonded.

Furthermore, tool 23 has conventional means such as a vacuum system for selectively gripping the lower container portion therein.

Upper carrier head 12 is joined by shaft 24 to cam follower 17. Cam follower 17 is rotatably mounted on shaft 24. Also mounted on carrier head 12 is an air oscillator 25 acting through a pin joint 26 to an oscillatory diaphragm 27 which in turn is fixedly attached to carrier head 12.

Oscillator 25 has a slidable shaft 28 extending downwardly therefrom to which is connected an upper tool spindle 29 having an upper tool 30 attached thereto. Tool spindle 29 passes through air bearing 31 mounted in a bearing housing 32 which is fixedly attached to carrier head 12. Air bearing 31 allows slidable vertical movement between spindle 29 and carrier assembly 12.

Upper tool 30 has conventional means such as vacuum means for tightly gripping the upper portion of the container to be joined to the lower portion held in tool 23. An air supply source 33 provides air to bearing 31, a second air supply source 34 provides air to oscillator 25, and a third air supply 35 provides air to diaphragm 27.

Oscillatory diaphragm 27 is connected to oscillator 25 to provide amplitude adjustment of the oscillatory motion generated therein.

In typical operation, a pair of upper and lower container portions are denested from a stack thereof by a separate denesting assembly (not shown) and rotated through the various conveying systems associated with the aforementioned incorporated patented structures such that a bottom portion is secured within tool 23 and an upper portion held in upper tool 30. The movement of carrier 12 and carrier 14 around the circular cam heads 13 and 15 provides vertical movement between tools 23 and 30 bringing the container sections into close proximity. When the carrier assemblies 12 and 14, which traverse circularly around cam heads 13 and 15 as a single unit, have reached a predetermined point with respect to cam grooves 19 and 21, tools 23 and 30 will have moved into their closest position thus bringing the upper and lower container sections into conjoining relationship.Simultaneously with the joining of the upper and lower container sections, air is supplied via tube 34 to the air oscillator 25 thus providing a low frequency oscillation of the upper container held in tool 30 within the lower container clamped in tool 23 to sufficiently generate enough heat between the two container sections to provide a hermetic bonding therebetween. The number of oscillations necessary to provide bonding depend upon various parameters including the type of plastic utilized in the containers, as well as the container size and the frequency and amplitude of the oscillations. These will be known to the operator prior to adjusting the machinery, and the time and frequency of the oscillations will have been preset such that at the moment bonding is beginning, the oscillations will be terminated to allow the container sections to form a good bond.The air oscillator terminates oscillations in the lowermost position such that the container sections will be fully joined. Shortly after the oscillations have ceased and bonding has been achieved, movement of the carrier assemblies 12 and 14 around cam heads 13 and 1 5 by means of the engagement of cam followers 16 and 17 in cam grooves 19 and 21 will move the carrier assemblies vertically apart and allow removal of the bonded container sections. These will then be transported via conventional means away from the bonding assembly.

Figure 5 is the schematic representation of the rotary air joint to which air supply tubes 33, 34, and 35 are connected. Figure 5 illustrates the rotary joint 40 having an air supply outlet 41 to connect with diaphragm supply tube 35, a second air supply port 42 connectible to air oscillator supply tube 34, and a third air supply port 43 connectible to air bearings supply tube 33. As the carrier assemblies 12 and 14 are rotated about their respective cam heads 13 and 15, the air supply ports 41 43 communicate with the various supply tubes to supply a properly timed sufficient quantity of air into the various air actuated components of the assembly.

Referring now to Figure 6, the second embodiment of the invention is disclosed, which embodiment is particularly useful for high frequency oscillatory bonding of container parts. In this embodiment the carrier assembly of the first embodiment has been replaced by a high frequency carrier assembly 100. This carrier assembly is mounted on similar cam heads 13 and 1 5 by roller followers 17 and 16. Assembly 100 comprises an upper carrier body 101 and a lower roller body 102. Upper tool body 101 has located thereon a mounting bracket 103 which mounts an ultrasonic transducer 104 lying in a vertical plane substantially parallel to cam plate 13. Transducer 104, which is electrically operated, is connected to a power source via electrical connection 105.

At the lower end of transducer 104 is a pin connection 106 connecting an upper spindle 107 to the transducer. An air bearing 108 connected to body 101 supports spindle 107 in vertically slidable orientation. An upper container retention tool 109 is secured at the lower end of spindle 107. Retainer tool 109 preferably has an internal cavity formed in the general shape of the container top to be welded. The lower assembly 102 comprises a lower spindle 110 mounted on carrier block 102 and having a lower container retention tool 111 mounted at the top thereof.

Tool 111 has an internal cavity similarly shaped to the lower portion of the plastic container to be welded. Tools 109 and 111 have conventional means for clamping tightly onto container sections.

In typical operation, the two carrier assemblies comprising a single station 100, will be rotated about their respective cam plates 13 and 15 with roller followers 17 and 1-6 engaged in cam grooves 20 and 21. This rotary movement and concurrent camming action around plates 13 and 15 by the station assembly results in a vertical movement of the upper and lower spindles toward and away from each other. At one point in this operation, while the upper and lower tools 109 and 111 are spaced apart, a plastic container top will be located in tool 109 and a plastic container bottom will be located in tool 111 by means conventional in the art. Additional movement of the cam followers in cam channels serves to translate the upper and lower spindles toward each other until the upper and lower plastic container sections are brought into mating contact.At this point in time the transducer will be supplied with electric power through lead 105 causing a very high frequency oscillation of the upper spindle 107 to occur, which in turn oscillates the upper plastic container with respect to the lower plastic container, setting up friction forces which result in a high heat generation and a subsequent welding of the upper and lower container sections together to form an hermetic seal. The continuous movement of the assembly around the cam plates then spreads the upper and lower spindles apart, allowing removal of the welded container unit from the upper and lower tools by known means.

Figure 7 is a schematic diagram of a rotary joint located near the central longitudinal axis of the total assembly. In Figure 7 the circuits for the electrical supply are indicated at 1 12 and 113.

The air supply tube is connected to a rotary air joint 1 14 to provide air to the air bearing 1 18. In addition, conventional means such as vacuum or mechanical means can be provided in the tool holders 109 and 1 1 1 to secure the plastic containers therein during the oscillatory welding stage.

Figure 8 is a plan schematic view of a feed system 200 for the bonding assembly. The feed system comprises a rotary infeed such as starwheel 201, providing delivery of containers into the various stations 10, and the exit wheel 202 comprising a starwheel for removing the bonded containers after the welding process has been accomplished. The multi-station oscillatory welding system 11 is shown having ten individual welding stations 10 illustrated.

Figures 1-3 illustrate various joints that can be welded utilizing the present assembly and rigid plastic container sections. Figure 1 illustrates a partial cross-sectional view of upper container 301 which is fused to a lower container section 302. This type of joint is normally referred to as a "compressive shear" joint. The outer diameter of the lower section 302 is a few thousandths inch larger than the inner diameter of the upper section 301. Section 301 is forced over section 302 to provide an air-tight fit and the oscillation between the two sections provides, through the heat of friction, a sufficient melting of the thermoplastic material to form a tight hermetic bond therebetween.Figure 2 represents a partial crosssectional side view of a fusion joint between two plastic articles, such as two sections of a container, or a container wall and a container bottom. This type of joint is generally referred to as an "energy director" joint. In this joint the side wall 401 of a container section is oscillated between upwardly extending flanges 402 and 403 of a plastic bottom section 404. The wall section 401 preferably has a slight interference fit in between upper flanges 402 and 403 to provide sufficient friction heat to bond the bottom section to the wall 401.

Figure 3 illustrates an alternate embodiment of the clamping function of the upper tool 501 of a container section 502. The container section 502 is to be friction welded to the lower container section 503. In this embodiment a wedge shaped clamp 504 connected to a first cam track located on upper cam plate 13 grips the container member 502. Member 504 is wedge shaped into a diverging orientation at the lower end and a slidable tightening ring 505 is located around the outer periphery of the wedge shaped clamping member. A second cam track located on the upper cam plate directs the vertical movement of clamping member 505 downward on wedge member 504 to provide an inward compression of container member 502.The timing of the first and second cam tracks on the upper arm member is such that member 505 is lowered on member 504 to compress container member 502 down upon container member 503 after container member 503 has just entered the barrel flange area 502a.

Thereupon member 505 is moved downward to compress clamp 504 and container 502 into compression on container 503. After the downward clamping motion of outer member 505, oscillations are generated in the entire upper assembly to oscillate member 502 over 503 and provide sufficient heat of friction to bond the two container sections together.

Thus a welding system for friction welding plastic containers has been disclosed which is particularly advantageous for the joining of two thermoplastic container sections which are of a non-circular cross-sectional configuration. The present invention utilizes oscillatory axial motion as opposed to the conventional rotary motion of prior art spin-welders. The oscillatory motion being a translational motion rather than a rotating motion allows containers of almost any crosssectional configuration to be friction welded together. The present invention discloses embodiments for low frequency oscillatory welding of plastic articles, and apparatus for high frequency oscillatory welding apparatus.

Although a specific embodiment of the present invention has been described in the detailed description above, the description is not intended to limit the invention to the particular forms or embodiments disclosed therein since they are to be recognized as illustrative rather than restrictive and it will be obvious to those skilled in the art that the invention is not so limited. For example, whereas electrical transducers and air operated oscillatory apparatus are disclosed for providing oscillatory welding action, it is clear that other means such as hydraulic action and mechanical oscillations could be utilized in their place. Also, whereas the top container portion is oscillated in contact with the bottom container section, it is possible to oscillate the bottom section instead, or to even oscillate both sections of the container.

Thus the invention is declared to cover all changes and modifications of the specific examples of the invention herein disclosed for purposes of illustration which do not constitute departures from the spirit and scope of the invention.

Claims

1. Apparatus for friction welding two thermoplastic articles together, said apparatus comprising: a first holder adapted for clamping engagement of a first article to be welded, comprising first clamping means and a receptacle for receiving said first article; said first holder being mounted on a tool adapted for axial sliding movement; said tool being mounted slidably on a first base module; oscillator means connected to said first tool and said first base module and arranged to oscillate said first tool axially with respect to said first module; a second holder mounted on a second base module and adapted for clamping engagement of a second article to be welded to said first article, said second holder being axially aligned with said first holder in close proximity thereto, and comprising a receptacle for receiving said second article, and second clamping means for holding said second article in said second holder; and, means for moving said first and second holders back-and-forth between an article-engaged position and an articledisengaged position.

2. A friction welding apparatus according to Claim 1, wherein said moving means comprises roller follower means rotatably mounted on each said base module, and cam means formed in a base station and adapted to receive said follower means and impart relative axial movement to said holders.

3. A friction welding apparatus according to Claim 1 or Claim 2, wherein said oscillator means comprises a pneumatically-actuated lowfrequency oscillator adapted to oscillate at from 50 to 500 cycles per second.

4. A friction welding apparatus according to Claim 1,2 or 3, wherein said first and second clamping means comprise vacuum means in said holders.

5. A friction welding apparatus according to Claim 1 or 2, wherein said oscillator means comprises an electrically-actuated oscillator adapted to oscillate at from 50 cycles per second to 50,000 cycles per second.

6. A friction welding apparatus according to Claim 5, wherein said first and second clamping means comprise vacuum means in said holders.

7. A friction welding apparatus according to any one of the preceding claims, wherein said oscillator means includes means for varying the oscillatory frequency and means for varying the oscillatory amplitude thereof.

8. A multi-station friction welding assembly for the oscillatory bonding together of at least two thermoplastic articles and having at least two bonding stations thereon; said assembly comprising: a stationary base portion; an upper assembly mounted on said base portion; a lower assembly mounted on said base portion below said upper assembly; said upper and lower assemblies adapted to maintain circumferential alignment with each other on said base portion; at least one of said upper and lower assemblies further adapted to be moved axially back-andforth with respect to the other assembly on said base portion; means for moving at least one of said upper and lower assemblies axially back-andforth with respect to the other; each said bonding station further comprising: first holder means slidably mounted on one of said upper and lower assemblies, adapted to receive and clamp a first thermoplastic article to be bonded; oscillating means on said first holder means of oscillating said holder axially on said assembly; and, second holder means on the other of said upper and lower assemblies, axially aligned with said first holder means, and adapted to receive and clamp a second thermoplastic article to be bonded to a first thermoplastic article; selective power means for supplying actuating power to said oscillating means and said holder means at said bonding stations; said moving means being adapted to move said first holder back-and-forth between a first position where said thermoplastic articles are separated and a second position where said thermoplastic articles are telescopically engaged with each other; and, said oscillating means being adapted to oscillate only when said first and second holder means are in said article-engaged position, and said oscillating means further comprising frequency and amplitude adjusting means adapted to allow adjustment of the amplitude and frequency of said oscillating action to maintain said thermoplastic articles in telescopic engagement during oscillation thereof.

9. A multi-station friction welding assembly according to Claim 8, wherein said upper and lower assemblies are rotatably mounted on said stationary base portion and said moving means comprises cam means on said base portion and cam follower means on at least one of said upper and lower assemblies.

10. A multi-station friction welding assembly according to Claim 9, wherein both said upper and lower assemblies are adapted to move axially and rotatably on said base portion and both have cam follower means engaged with said cam means.

11. A multi-station friction welding assembly according to Claim 8, Claim 9, or Claim 10, wherein said oscillating means comprises a pneumatic oscillator.

12. A multi-station friction welding assembly according to Claim 11, wherein said pneumatic oscillator is adapted for preselective oscillation at a frequency from 50 to 500 cycles per second.

13. A multi-station welding assembly according to Claim 12, wherein said pneumatic oscillator is adapted for preselective oscillation at a frequency from 120 to 240 cycles per second.

14. A multi-station friction welding assembly according to Claim 8, Claim 9, or Claim 10, wherein said oscillating means comprises an electrically actuated oscillator adapted for preselective oscillation at a frequency from 50 cycles per second to 50,000 cycles per second.

15. A multi-station friction welding assembly according to Claim 14, wherein said electrically actuated oscillator is adapted for preselective oscillation at a frequency from 20,000 to 40,000 cycles per second.

16. A multi-station friction welding assembly according to Claim 8, Claim 9, or Claim 1 0, wherein said oscillating means comprises a pneumatic oscillator adapted for preselective oscillation at a frequency from 120 to 240 cycles per second; said first and second holder means have vacuum means for clamping thermoplastic articles to be bonded; and, said welding assembly further comprises means for infeeding thermoplastic articles to said bonding stations, and means for removing bonded thermoplastic articles from said bonding stations.

17. A multi-station friction welding assembly according to Claim 8, Claim 9, or Claim 10, wherein said oscillating means comprises an electrically actuated oscillator adapted for preselective oscillation at a frequency from 20,000 to 40,000 cycles per second; said first and second holder means have vacuum means for clamping thermoplastic articles to be bonded; and, said welding assembly further comprises means for infeeding thermoplastic articles to said bonding stations, and means for removing bonded thermoplastic articles from' said bonding stations.

18. A method of welding at least two similarly configured thermoplastic sections together having relatively tight-fitting complementary joinder portions, said method comprising: sliding said tight-fitting portions together into telescopic conjoinment; oscillating said portions axially with respect to each other at a sufficiently rapid rate and for a sufficient period of time to generate enough heat to melt the areas of contact therebetween; and, bringing said sections into a final desirable position and allowing said heated areas to cool, thereby welding said sections together.

19. A method according to Claim 18, wherein said thermoplastic sections are sized to provide an interference fit therebetween.

20. A method according to Claim 18 or Claim 19, wherein said thermoplastic sections are made from organic thermoplastic resins each having melt temperatures relatively close to the other.

21. A method according to Claim 18 or Claim 19, wherein said thermoplastic sections are made from identical organic resins.

22. A method of forming a container from at least two thermoplastic sections each having a non-circular cross-sectional configuration which closely matches the other section, said method comprising: clamping said container sections into separate holder means providing axial telescopic alignment of the sections with each other; oscillating at least one of said holder means at a sufficiently rapid rate for a sufficient period of time, while maintaining said sections in telescoped arrangement, to generate enough heat to melt the contact areas therebetween; bringing said telescoped sections to a final preselected desirable position with respect to each other while still partially melted; and, allowing said heated areas to cool sufficiently to solidify said heated thermoplastic areas.

23. A method according to Claim 22, wherein at least one of said sections is an organic polymer selected from styrenic resins, polystyrenes, polypropylenes, polycarbonates, polyethylenes, high density polyethylenes, polyethylene terephthalates, and polyethylene glycol terephthalates.

24. A method according to Claim 22 or Claim 23, wherein said thermoplastic sections are made of thermoplastic materials having melt temperatures within about 300F of each other.

25. A method according to Claim 22, 23 or 24, wherein said oscillating step is performed at a frequency of from 120 to 240 cycles per second.

26. A method according to Claim 22, 23 or 24, wherein said oscillating step is performed at a frequency of from 20,000 to 40,000 cycles per second.

27. A method according to Claim 22, 23 or 24, wherein said oscillating step is performed at a frequency of from 50 cycles per second to 50,000 cycles per second.

28. A method according to any one of Claims 22 to 27, wherein said thermoplastic sections are made from at least one amorphous organic resin.

29. A method according to any one of Claims 22 to 27, wherein said thermoplastic sections are made from at least one crystalline organic resin.

30. A welded thermoplastic article produced by the process comprising the steps of: forming a portion of said article in a first section having a shaped weld region thereon comprising a thermoplastic material; forming another portion of said article in a second section comprising a thermoplastic material having a melt temperature close to said first section material, said second section having a shaped weld region thereon adapted for close-fitting telescopic engagement with said first section weld region; joining said portions together in telescopic engagement at said weld regions; oscillating said portions axially at a sufficiently high frequency and for a sufficient period of time to generate enough heat in said weld regions to at least partially melt a portion of said thermoplastic materials therein; bringing said portions to a desired predetermined telescopic engaged position while said thermoplastic material is at least partially melted; and allowing said portions to cool in said desired telescopic engagement until solidified, thereby welding said portions together.

31. An article according to Claim 30, wherein said thermoplastic materials each comprise an organic resin, and said oscillating step is performed at a frequency of from 50 cycles per second to 50,000 cycles per second.

32. An article according to Claim 30 or 31, wherein said thermoplastic materials each comprise an organic resin, each said resin having a melt temperature within about 300F of the other.

33. An article according to Claim 30, Claim 31, or Claim 32 wherein said weld regions are noncircular in cross-sectional configuration.

34. An article according to Claim 30, Claim 31, or Claim 32 wherein said initial telescopic engagement of said weld regions comprises an interference fit.

35. An article according to Claim 3O, Claim 31, or Claim 32 wherein said weld regions are noncircular in cross-sectional configuration and are telescoped together initially with an interference fit.

36. An article according to Claim 30, wherein said thermoplastic materials each comprise an organic resin, each having a melt temperature within about 300F of the other, said weld regions are non-circular in cross-sectional configuration and have an initial interference fit with each other, and said oscillating step occurs at a frequency of from 120 cycles per second to 240 cycles per second.

37. An article according to Claim 30, wherein said thermoplastic materials each comprise an organic resin, each having a melt temperature within about 300F of the other, said weld regions are non-circular in cross-sectional configuration and have an initial interference fit with each other, and said oscillating step occurs at a frequency of from 20,000 cycles per second to 40,000 cycles per second.

38. An article according to any one of Claims 30 to 38. wherein said article is a container.

39. A container having a non-circular crosssectional configuration and being made at least partially of a thermoplastic organic resin, said container produced by the process comprising the steps of: forming a portion of said article in a first non-circular section having a weld region thereon comprising an organic thermoplastic resin; forming an additional portion of said article in a second non-circular section having a weld region thereon comprising an organic thermoplastic resin; said organic resins having melt temperatures within about 300F of each other; said weld regions adapted for interference-fit telescopic engagement with each other; oscillating at least one of said sections axially with respect to the other section while maintaining said telescopic engagement, said oscillating occurring at a frequency of from 50 cycles per second to 50,000 cycles per second and for a period of time sufficient to melt at least a portion of each of said weld regions; and, bringing said portions to a predetermined desired engaged position and thereafter allowing said melted material to cool, thereby welding said portions together.

40. A container according to Claim 39, wherein said organic resins are selected from styrenes, polystyrenes, polyethylenes, and polyethylene terephthalates.

41. A container according to Claim 39 or Claim 40, wherein said oscillating step is performed at a frequency of from 120 to 240 cycles per second.

42. A container according to Claim 39 or Claim 40, wherein said oscillating step is performed at a frequency of from 20,000 to 40,000 cycles per second.

43. Apparatus for friction welding two thermoplastic articles together substantially as hereinbefore described with reference to the accompanying drawings.

44. A method of friction welding at least two similarly configured thermoplastic sections together substantially as hereinbefore described with reference to the accompanying drawings.

45. A container or other friction welded article whenever prepared by a method as claimed in any one of Claims 18 to 29 and 44.