Device for transporting a hollow body, installation provided with such devices, and method for conveying a hollow body attached to such a device

Abstract

The preform conveying installation ( 2 ) comprises gripping members ( 6 ) and heads ( 7 ) for feeding them into the heating oven, and includes a detection system that selects preforms likely to cause incidents in said heating oven, and means for detaching each selected preform from its gripping head ( 7 ), which means apply pressure to the interior of the selected preform ( 2 ), on its base, and these consist of a nozzle ( 15 ) capable of directing a jet of pressurized fluid at said base. The gripping member ( 6 ) and the gripping head ( 7 ) comprise an orifice in the form of a bore ( 9 ) that enables the jet of pressurized fluid to be applied directly into the selected preform.

1 . An installation for conveying preforms to a processing unit such as a heating oven in which they are taken to an appropriate temperature in order subsequently to be formed by stretch-blow molding, which installation comprises:
 gripping members which are carried by an endless conveyor chain and which are each furnished with a gripping head in order to carry said preforms and in order to transfer them into said heating oven,   at least one detection system placed on the path of said preforms upstream of said heating oven, which detection system, such as a shape-recognition camera, selects the preforms that are likely to cause incidents in said heating oven, such as, for example, preforms the alignment of which does not correspond with that of the main axis of their gripping head,   means for detaching each selected preform from its gripping head,   an apparatus, such as a programmable controller, to command the ejection of the selected preform according to the information originating from said detection system,   means for retrieving the ejected preforms, wherein it comprises means for applying a pressure to the inside of the selected preform, on its bottom, and in particular a sufficient pressure to overcome the forces of adhesion between said selected preform and its gripping head, in order to detach them.   
   
   
       2 . The installation as claimed in  claim 1 , wherein the means capable of applying a pressure in the selected preform, on its bottom, consist:
 of a nozzle capable of spraying a jet of pressurized fluid at the bottom of said selected preform, and,   of an orifice in the shape of a bore arranged in the member and in the gripping head of said selected preform, said jet of pressurized fluid being administered when said bore passes in front of said nozzle.   
   
   
       3 . The installation as claimed in  claim 2 , wherein the bore, into which the pressurized fluid intended for the selected preform is injected, comprises an upstream aperture in the form of a funnel which has a narrowing of its cross section in the direction of the downstream aperture. 
   
   
       4 . The installation as claimed in  claim 3 , wherein it comprises means for injecting fluid at a pressure of from 2 to 5 bar. 
   
   
       5 . The installation as claimed in  claim 1 , wherein the programmable controller used for commanding the injection of the pressurized fluid comprises a program arranged in order to establish an appropriate phase for the administration of said pressurized fluid to the selected preform, which phase extends for a period substantially greater than the time taken by said selected preform to pass in front of the nozzle so as to ensure an injection time of said pressurized fluid into the bore that is long enough to ensure the ejection of said selected preform. 
   
   
       6 . A method for releasing a preform or preforms while they are conveyed to the heating oven, in order to eliminate each preform capable of creating an incident during its passage in said heating oven, said method consisting:
 in monitoring the preforms which pass by, before they enter said heating oven, in order to detect, in said preforms, a flaw capable of causing incidents in said heating oven,   in detaching each preform that is qualified as undesirable from its gripping head, upstream of said heating oven,   in collecting the rejected preform in an appropriate container, wherein it consists in applying an appropriate force to the inside of said undesirable preform, on its bottom, and in particular a sufficient force to overcome the forces of pressure and of friction that are applied between said undesirable preform and its gripping head.   
   
   
       7 . The method for releasing a preform or preforms as claimed in  claim 6 , wherein it consists in separating the undesirable preform from its gripping head via an injection, in an appropriate bore of said gripping head, of a jet of pressurized fluid which penetrates the inner volume of said undesirable preform. 
   
   
       8 . The method for releasing a preform or preforms as claimed in  claim 6 , wherein it consists in injecting the jet of fluid at a pressure of from 2 to 5 bar. 
   
   
       9 . The method for releasing a preform or preforms as claimed in  claim 6 , wherein it consists in anticipating the passage of the undesirable preform in order to trigger the injection of the jet of pressurized fluid into said preform and in maintaining this injection of said jet of fluid at least until the gripping head has passed in front of the nozzle for spraying said fluid.