EP0052490A2 — Thermoplastics articles and method and apparatus …

Claim 1

Independent Claim 172 words

A process for forming at least partly biaxially oriented tubular articles from an elongate tube (10) of thermoplastics material, the process being characterised by repeatedly performing a cycle of operations each including the following steps: engaging the tube by a first clamping means (11,12) over a first region at a leading end (10') of the tube and by a second clamping means (13,14) over a second region at a spacing from the first region, so as to define between the clamping regions a portion of the tube to be longitudinally stretched and radially expanded; moving the clamping means apart to stretch the tube portion longitudinally and admitting pressure fluid to the tube portion to expand it radially, such stretching and expansion forming a bubble (100) of biaxially oriented thermoplastics material adjacent the leading end of the tube; and severing at least a substantial part of the bubble from the tube to form the tube with a new end as the said leading end of the tube for the succeeding cycle of operations.

Claim 2

Dependent Claim 172 words

A process for forming at least partly biaxially oriented tubular articles from an elongate tube (10) of thermoplastics material, the process being characterised by repeatedly performing a cycle of operations each including the following steps: engaging the tube by a first clamping means (11,12) over a first region at a leading end (10') of the tube and by a second clamping means (13,14) over a second region at a spacing from the first region, so as to define between the clamping regions a portion of the tube to be longitudinally stretched and radially expanded; moving the clamping means apart to stretch the tube portion longitudinally and admitting pressure fluid to the tube portion to expand it radially, such stretching and expansion forming a bubble (100) of biaxially oriented thermoplastics material adjacent the leading end of the tube; and severing at least a substantial part of the bubble from the tube to form the tube with a new end as the said leading end of the tube for the succeeding cycle of operations.

Claim 3

Dependent Claim 51 words

A process according to claim 1, characterised in that for each cycle of operations it includes the further step of confining the tube portion within a mould cavity (12) during its stretching and expansion to form the bubble, the bubble thereby being conformed to the mould cavity by the pressure fluid.

Claim 4

Dependent Claim 42 words

A process according to claim 1 or claim 2, characterised in that the tube end (10') is flared, the severance of the bubble being such as to leave part of the bubble as the tube end for the succeeding cycle of operations.

Claim 5

Dependent Claim 27 words

A process according to any preceding claim, which is further characterised by subdividing each severed bubble to form therefrom one or more parts as said tubular articles.

Claim 6

Dependent Claim 22 words

A process according to claim 4, characterised in that the or each said part of each severed bubble is of right-cylindrical form.

Claim 7

Dependent Claim 40 words

A process according to claim 4 or claim 5, which is characterised by the further step of forming the or each said part of each severed bubble as a container by attaching a closure member (30,31) to each end thereof.

Claim 8

Dependent Claim 69 words

A process according to claim 6, characterised in that the or each container is intended to be heat- processable together with its contents, the process comprising subjecting the thermoplastics material of the respective said severed bubble part to a heat treatment whilst it is restrained against excessive dimensional change, the heat treatment being such as to give the thermoplastics material dimensional stability at the processing temperature to be employed.

Claim 9

Dependent Claim 16 words

A process according to any preceding claim, characterised in that the thermoplastics material is polyethylene terephthalate.

Claim 10

Dependent Claim 197 words

Apparatus for forming at least partly biaxially oriented tubular articles from an elongate tube (10) of thermoplastics material by a repeated cycle of operations, which, apparatus is characterised in that it comprises a first clamping means (11,12) arranged for engaging a leading end (10') of the tube over a first clamping region, a second clamping means (13,14) arranged for engaging the tube over a second clamping region at a spacing from the first, the first and second clamping means being relatively reciprocable longitudinally of the tube, stretch means (34) to move the clamping means apart with the tube engaged thereby so as longitudinally to stretch the portion of the tube lying between the clamping regions, fluid pressure means (103,104) operable to supply pressure fluid to the interior of the tube portion so as to expand it radially, such stretching and radial expansion forming a bubble of biaxially oriented thermoplastics material adjacent the leading end of the tube, and severance means (121) operable to sever at least a substantial part of the bubble from the tube to form the tube with a new end as the said leading end of the tube for the succeeding cycle of operations.

Claim 11

Dependent Claim 197 words

Apparatus for forming at least partly biaxially oriented tubular articles from an elongate tube (10) of thermoplastics material by a repeated cycle of operations, which, apparatus is characterised in that it comprises a first clamping means (11,12) arranged for engaging a leading end (10') of the tube over a first clamping region, a second clamping means (13,14) arranged for engaging the tube over a second clamping region at a spacing from the first, the first and second clamping means being relatively reciprocable longitudinally of the tube, stretch means (34) to move the clamping means apart with the tube engaged thereby so as longitudinally to stretch the portion of the tube lying between the clamping regions, fluid pressure means (103,104) operable to supply pressure fluid to the interior of the tube portion so as to expand it radially, such stretching and radial expansion forming a bubble of biaxially oriented thermoplastics material adjacent the leading end of the tube, and severance means (121) operable to sever at least a substantial part of the bubble from the tube to form the tube with a new end as the said leading end of the tube for the succeeding cycle of operations.

Claim 12

Dependent Claim 75 words

Apparatus according to claim 9, which is further characterised by a mould (12) having a mould cavity within which the tube portion may be confined during its stretching and expansion to form the bubble, the bubble thereby being conformed to the mould cavity by the pressure fluid, the mould comprising a plurality of portions which are closable together to form the mould cavity but which are separable to enable the tube bubble to be ejected.

Claim 13

Dependent Claim 50 words

Apparatus according to claim 10, characterised in that the first clamping means comprises the mould portions (12), and a clamping member (11) which is insertable into the tube end, the mould portions being adapted, when closed to form the mould cavity, to clamp the tube end against the clamping member.

Claim 14

Dependent Claim 34 words

Apparatus according to claim 11, characterised in that the severance means (121) is positioned to leave part of the bubble as the tube end for the succeeding operation, the tube end thereby being flared.

Claim 15

Dependent Claim 60 words

Apparatus according to claim 11 or claim 12, characterised in that the second clamping means comprises an elongate clamping mandrel (13) arranged to extend into- the tube from the clamping member at the tube end, and a collar (14) having an aperture for receiving the tube therethrough and contractable to clamp the tube.against the mandrel at the second clamping region.

Claim 16

Dependent Claim 111 words

Apparatus according to claim 13, characterised in that the .collar (14) comprises a plurality of relatively movable clamping elements wh.ich present a common frustoconical surface (81) facing away from the said tube end and are biassed resiliently apart to limiting, non-operative positions, for contracting the collar (l4) onto the tube the second clamping means comprising a collar actuating member (66) with'an aperture for receiving the tube therethrough and having a frustoconical surface (84) for complementary engagement with the frustoconical surface of the collar, and an actuator (71) arranged for moving the collar actuating-member longitudinally of the tube in the direction towards the tube end whereby to close the clamping elements together.

Claim 17

Dependent Claim 101 words

Apparatus according to any claim of claims 11 to 14, characterised in that the mould portions are mounted on a carriage (33) which is reciprocable longitudinally of the tube between an upstream position and a downstream position, the mould portions being separated during carriage movement in the downstream direction, for each downstream carriage movement the first clamping means being effective for the whole of the movement but the second clamping means and the fluid pressure means being effective for only a latter part of the movement, the formation of the bubble thereby occurring during the said latter part of the movement.

Claim 18

Dependent Claim 33 words

Apparatus according to claim 15, characterised in that it includes gripper members (21) operable when the carriage is in its upstream position to support the tube bubble 'for severance by the severance means.

Claim 19

Dependent Claim 25 words

Apparatus according to any claim of claims 9 to 16, characterised in that the severance means comprises a knife (121) operable transversely of the tube.

Claim 20

Dependent Claim 39 words

Apparatus according to claim 12, characterised in that it has an auxiliary clamping means (123,125) for operation instead of the first clamping means when the tube end is unflared for the first operating cycle of a sequence of cycles.

Claim 21

Dependent Claim 49 words

Apparatus according to claim 18, characterised in that the auxiliary clamping means comprises a plurality of clamping elements (125) which are mounted on the clamping member and simultaneously movable from non-operative positions to positions in which they externally engage the tube end to clamp the 'tube end between them.

Claim 22

Dependent Claim 71 words

Apparatus according to any claim of claims 9 to 19, characterised in that it is operatively linked with an extruder arranged for extruding the tube at a substantially constant extrusion speed, the extruder and/or the apparatus being reciprocable longitudinally of the tube to correlate the continuous motion of the tube as it emerges from the extruder with the intermittent advancing movement of the tube as said tubular articles are formed therefrom.

Claim 23

Dependent Claim 18 words

A tubular article made by a process or apparatus according to any claim of claims 1 to 20.

Claim 24

Dependent Claim 18 words

A container having a body made by a process according to any one of claims 1 to 8.

Claim 25

Dependent Claim 20 words

A container having a tubular wall of biaxially oriented thermoplastics material, and end closures closing the ends of the wall.

Claim 26

Dependent Claim 20 words

A container having a tubular wall of biaxially oriented thermoplastics material, and end closures closing the ends of the wall.

Thermoplastics articles and method and apparatus for making them

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