Manufacture of bottle with push-on closure

Abstract

A method of manufacture of a bottle which may be closed by a push-on closure, apparatus for manufacturing the same, a bottle and a closure for the bottle. A bottle is manufactured in a multi-component assembly. The bottle preform (not shown) is made by an injection molding technique, having detents on its upwardly and outwardly facing surfaces. It is then transferred to a blow mould where it is first heated, and then shaped by inserting a blow pin through the neck of the preform to stretch it in its longitudinal axis. During this operation, the top surface of the preform is bent down, such that the detent formed on the upwardly facing surface of the preform now extends laterally into the volume of the preform. The stretched preform is then blown to take the shape of the blow mould, forming the bottle. A closure is formed by injection moulding, and is held on the bottle by the laterally extending detents.

1 . A method of making a bottle having a body and a rim defining an opening for the bottle, the opening being capable of being closed by a push-on closure, the bottle being made of a material which is susceptible to deformation when heated, the method comprising the steps of: 
 injection moulding in an injection moulding apparatus a preform in the shape of a closed-end tube with a rim at its mouth, the rim comprising an outward generally-radial flange having an upper surface and a lower surface, a first detent simultaneously formed with the flange as an upstanding projection from the upper surface of the flange towards the radially inner end thereof, and a second radically-outward detent formed at the outer edge of the flange, the tube depending from the radially-inner edge of the flange;    placing the preform in a pressure moulding apparatus at an elevated temperature with the preform being located at least in part by means of the second detent;    moving the flange and the first detent downwardly and outwardly relative to the second detent so that the upper surface of the flange now faces inwardly and the first detent projects inwardly into the opening for the bottle, whereby a closure can be push-fitted onto the rim of the bottle to engage both the first inwardly-facing detent and the second outwardly-facing detent; and    expanding the tube under pressure to form the body of the bottle.    
   
   
       2 . A method according to  claim 1 , in which the moving step is caused at least in part by means of a portion of a core of the pressure moulding apparatus bearing against the upper surface of the flange and/or the first detent.  
   
   
       3 . A method according to  claim 1 , in which the moving step is caused at least in part by differential pressure applied between the interior of the preform and the exterior.  
   
   
       4 . A method according to  claim 1 , in which the moving step is caused at least in part by downward stretching applied to the tube portion of the preform.  
   
   
       5 . A method according to  claim 1 , further comprising the step of longitudinally stretching the tube portion of the preform.  
   
   
       6 . A method according to  claim 1 , further comprising the step of applying differential pressure between the interior of the preform and the exterior to expand the tube portion to form the body of the bottle.  
   
   
       7 . A method according to  claim 1 , in which the preform is formed with an upwardly-extending sealing portion extending above the second detent in the rim portion.  
   
   
       8 . A method according to  claim 1 , in which the rim includes a downward flange depending from the outer end of the radial flange.  
   
   
       9 . A method according to  claim 8 , in which in the moving step the lower surface of the radial flange moves into homogeneous contact with the downward flange.  
   
   
       10 . A method according to  claim 1 , in which the first detent extends continuously around the mouth of the preform.  
   
   
       11 . A method according to  claim 1 , in which the second detent extends continuously around the mouth of the preform.  
   
   
       12 . A method according to  claim 1 , in which the material is seleted from the groups comprising polyethylene terephthalate, polyethylene naphthalate and co-polymers and blends thereof.  
   
   
       13 . A method according to  claim 1 , further comprising the steps of filling the bottle with liquid, and push-fitting a closure to the bottle, in which the closure includes first and second engaging portions for engaging respectively with the first and second detents to secure the closure on the bottle.  
   
   
       14 . A method according to  claim 13 , in which the first and/or the second engaging portions are discontinuous around the closure.  
   
   
       15 . Apparatus for making a bottle having a body and a rim portion defining an opening for the bottle, the opening being capable of being closed by a push-on closure, the apparatus comprising: 
 injection moulding apparatus shaped and arranged to produce a preform in the shape of a closed-end tube with a rim at its mouth, the rim comprising an outward generally-radial flange having an upper surface and a lower surface, a first detent upstanding from the upper surface of the flange towards the radially inner end thereof, and a second radially-outward detent at the outer edge of the flange with the tube depending from the radially-inner edge of the flange; and pressure moulding apparatus having mould parts defining a mould cavity and comprising means to locate the preform in the mould cavity with the second detent in a fixed location therein, means for moving the flange and the first detent downwardly and outwardly relative to the second detent such that the upper surface of the flange faces inwardly and the first detent projects inwardly into the opening for the bottle, and means for applying a pressure differential between the interior of the tube and the extension to expand the tube into contact with the mould parts defining the mould cavity.    
   
   
       16 . A bottle made of a material which is susceptible to deformation when heated, the bottle comprising a body portion and a rim portion, the rim portion being narrower than the body portion and providing an opening constituting the mouth of the bottle, the rim portion including an inwardly-facing detent facing into the opening and an outwardly-facing detent facing radially outwardly and a portion between the detents for constituting a sealing region, and the bottle being provided with a sealing closure, the closure having a peripheral trough defined between inner and outer cylindrical flanges, the inner cylindrical flange carrying means for engaging the inwardly-facing detent and the outer cylindrical flange carrying means for engaging the outwardly-facing detent, the closure further comprising a sealing portion in the trough for sealing engagement with the sealing region of the rim portion of the bottle.  
   
   
       17 . A bottle made of a material which is susceptible to deformation when heated, the bottle comprising a body portion and a rim portion, the rim portion being narrower than the body portion and providing an opening constituting the mouth of the bottle, the rim portion including an inwardly-facing detent facing into the opening and an outwardly-facing detent facing radially outwardly, a portion between the detents being adapted to constitute a sealing region.  
   
   
       18 . A closure for use with the bottle of  claim 17 , the closure having a peripheral trough defined between inner and outer cylindrical flanges, the inner cylindrical flange carrying engagement means for engaging the inwardly-facing detent on the bottle and the outer cylindrical flange carrying engagement means for engaging the outwardly-facing detent on the bottle, and a sealing portion in the trough for sealing engagement with the sealing region of the rim portion of the bottle.