Mold and Method for the Manufacture of Holders Such as Tub-Shaped Containers

Abstract

This invention relates to a mold for the manufacture of holders, comprising at least two mold halves moveable relatively to each other in a first direction of movement and a mold cavity, the mold being substantially defined by a female part and a matching male part, while at least the female part and/or the male part is arranged so as to be moveable such that within the mold, the male part and/or the female part can be brought into a first position wherein between a forward end, facing, in a first direction of movement, towards the mold cavity, and an opposite bottom part of the female part, there is a relatively large, first distance, and a second position wherein between said forward end and said bottom part there is relatively small second distance.

1 . A mold for manufacturing holders, comprising at least two mold halves moveable relative to each other in a first direction of movement and a mold cavity, the mold cavity being substantially defined by a female part and a matching male part, while at least the female part and/or the male part is arranged so as to be moveable such, that within the mold, the male part and/or the female part can be brought into a first position wherein between a forward end, facing, in a first direction of movement, towards the mold cavity, and an opposite bottom part of the female part, there is a relatively large, first distance, and a second position wherein between said forward end and said bottom part there is a relatively small second distance. 
   
   
       2 . A mold according to  claim 1 , wherein at least one inlet opening is provided in or near a space between said forward end of the male part and said bottom part of the female part. 
   
   
       3 . A mold according to  claim 2 , wherein said inlet opening is provided in the male part. 
   
   
       4 . A mold according to  claim 1 , wherein the male part is frustoconical and the female part has a corresponding shape, such that with the male and female part in the second position, between the two parts, there is a virtually constant distance. 
   
   
       5 . A mold according to  claim 1 , wherein the male part is truncate block-shaped and the female part has a corresponding shape, such that with the male and female part in the second position, between the two parts, there is a virtually constant distance. 
   
   
       6 . A mold according to  claim 1 , wherein at least the male part or the female part is biased in the second position. 
   
   
       7 . A mold according to  claim 1 , wherein a pressure member is provided for actively keeping the male part and/or the female part in the first position, which pressure member is retractable for having the male and female part move from the first position to the second position. 
   
   
       8 . A mold according to  claim 7 , wherein the pressure member extends around at least a part of the male part and, with the mold closed, can force, at least hold, the female part in the first position. 
   
   
       9 . A mold according to  claim 8 , wherein the pressure member is designed as stripper ring. 
   
   
       10 . A mold according to  claim 1 , wherein at least one moving male and/or female part is forced into the first position by spring means, in particular gas-filled spring means. 
   
   
       11 . A mold according to  claim 10 , wherein the spring means are designed such that the respective male or female part can be pushed away to the first position by plastic flowing into the mold cavity, and, when the injection pressure of the plastic falls, is forced to the second position by the spring means. 
   
   
       12 . A mold according to  claim 1 , wherein the or each moveable part is arranged for movement to a product forming position after the mold has been closed. 
   
   
       13 . A mold according to  claim 1 , wherein the mold is of multi cavity design, while for each mold cavity at least one moveable part is provided. 
   
   
       14 . A method for manufacturing plastic, thin-walled products, wherein in a closed mold, according to  claim 1 , in a mold cavity, a male and/or female part is brought to a position moved backwards, while or whereupon plastic is introduced into the mold cavity, whereupon the male part and/or the female part is brought to a position moved forward, while forcing at least a part of the plastic away such that the entire mold cavity is filled, while in the position when moved backwards, between a forward end of the male part in the direction of movement and a bottom of the female part, there is a larger distance than in the position when moved forward, while the distance between the remaining parts of the male and female part remains virtually the same. 
   
   
       15 . A method according to  claim 14 , wherein as a male part a substantially frustoconical or truncate block-shaped part is used, while a female part with a cavity having a corresponding form is used. 
   
   
       16 . A method according to  claim 14 , wherein a holder is formed with a bottom surface having a thickness which is approximately equal to or is preferably smaller than the thickness of a longitudinal wall extending away therefrom.