Abstract:
A mold cooling system for an I.S. machine wherein cooling air is supplied to vertical cooling holes defined in the molds either at their ends or midway along their length.

Description:
This invention relates to the cooling of molds at a blow station of an I.S. type glassware forming machine. 
     BACKGROUND OF THE INVENTION 
     In the production of glass containers in an I.S. type machine, glass is formed a gob of glass is delivered to a blank or parison mold comprising two mold members which are supported by a mold open and close mechanism (the blank station of the machine). The glass in the mold cavity may be formed into a parison by a plunger moving upwardly into the mold cavity (a lower portion of the glass is forced into a neck ring of the mold to form the finish of the final bottle). The plunger is then withdrawn and the parison, held at the finish, is carried away from the blank station to a blow station where it is blown to the required shape in the cavity of a blow mold. 
     It is necessary to cool the blank and blow molds, and this is commonly done by providing the mold members with cooling passages extending vertically therethrough from a lower end face to an upper end face of the mold member, as shown in EP 102820, and providing cooling air (either from the top or from the bottom) to these passages from a plenum chamber when the molds are closed. This method of cooling the mold has several advantages, one of which is that it is possible to calculate the cooling effect of given air pressure and given cooling passage dimensions. 
     Instead of supplying cooling air to the top or bottom of these cooling holes, EP patent specification number 0 576 745, discloses a system for supplying cooling air to these cooling holes at a location between the top and bottom of the holes so that cooling air will travel upwardly and downwardly through these holes from this inlet. 
     OBJECT OF THE INVENTION 
     It is an object of the present invention to provide improved cooling of a blow mold in a glassware making machine. 
     Other objects and advantages of the present invention will become apparent from the following portion of the specification and from the accompanying drawings which illustrate, in accordance with the mandate of the patent statutes, a presently preferred embodiment incorporating the principles of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the accompanying drawings: 
         FIG. 1  shows a view of a mold member of a blow mold used in an I. S. machine embodying the invention; 
         FIG. 2  shows a somewhat schematic perspective view of a mold mechanism; 
         FIG. 3  shows a cooling air chamber viewed from below; 
         FIG. 4  shows a view, corresponding to  FIG. 1 , of an alternative mold member embodying the invention; 
         FIG. 5  shows a cross section along the line V-V of  FIG. 4 ; 
         FIG. 6  shows a cross section, corresponding to  FIG. 5 , of a modified alternative mold member; and 
         FIG. 7  shows a control system for the cooling system. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     An I. S. machine forms a gob of molten glass into a parison at a blank station and delivers the formed parison to a blow station where it will be enclosed (from the finish down) by two opposed blow mold halves  2  ( FIG. 1 ) and a mold bottom  54  ( FIG. 2 ) which is captured by the closed mold halves. Each mold member  2  is generally half cylindrical in shape and comprises a generally cylindrical outer surface  3 , a mold recess  5  ( FIG. 2 ) and a top surface  4  adjacent to which are two flanged lugs  6 ,  8 , by which the mold member can be supported in the mold mechanism. The mold member  2  comprises a first, inner, generally circular array of straight cooling passages  10  which extend vertically through the mold member from its top face  4  to its flat bottom face  12 . The mold member also comprises a second, outer, circular array of straight cooling passages  14  extending vertically through the mold member, proximate to the outer cylindrical surface of the mold, from its top face  4  to its bottom face  12 . The mold member also comprises, as desired for the achievement of the desired cooling, further cooling passages, for example passages  17 , which may be extensions of the second array located proximate the end of the circular outer surface in the region of the flat mold sides  13 . Passages  18 , which are inward of the first array, are provided to supply vacuum to the mold when needed. Formed in the outer surface  3 , about half way up the cylindrical surface portion, is a recess  16  which extends horizontally, circumferentially round the cylindrical portion of the mold member  2  and is of a depth such that it extends across half the width of each of the passages  14  of the second array and thus opens directly into the passages  14 . 
       FIG. 2  shows a mold mechanism at a blow station of a double gob glass bottle making machine. The mold mechanism comprises a pair of arms  20 ,  22 , which are mounted on a vertical shaft  24  fixed to a table of the machine (not shown). These arms can be moved between an open position, as shown in  FIG. 2 , and a closed position by well known mechanism, not shown. The mold arm  20  will be described in detail, and it will be realized that the construction of the arm  22  is generally similar. The mold arm  20  comprises an upper extension  21  and a lower extension  23 . The upper extension  21  supports a hanger member  26  having two mold supporting ridges  27  which are adapted to support two mold members  2  by engagement of the flanged lugs  6 ,  8 , over the ridges  27 . Below the hanger member  26 , the lower extension  23  of the arm  20  supports an air supply chamber  28 . This chamber  28  ( FIG. 3 ) is formed by a base wall  30 , a v-shaped side wall  32 , a reinforcing internal wall  33  and a top wall  34 . That part of the chamber  28  which faces the mold members  2  is provided with curved surfaces  36  which bound openings  38  and are adapted to engage around the outer surfaces  3  of the two mold members around the boundaries of the recesses  16 . Formed in the base wall  30  is an opening  40  which is connected by way of tubes  42  and  44  and swivel joints  46  and  48  to a control cylinder V 1 , V 2  which is connected to a supply of cooling air under pressure. The cylinders V 1 , V 2  are secured to a table of the machine (not shown). It will be seen that the cylinders V 1 , V 2  supply cooling air to the chambers  28  on both sides of the machine. 
     A base plate  52  is secured to the table of the machine and comprises a pattern of upwardly facing outlets  54  which correspond to the pattern of the lower ends of the cooling passages  10 ,  14 ,  17  and  18  of the mold members when the mold members are in their closed position. Air is supplied to the outlets  54  at uniform pressure from a Base Plate Plenum Chamber  55  ( FIG. 7 ) fixed below the plate  52 . 
     As shown in  FIG. 7 , a Source Of Cooling Air Under Pressure  60  can be supplied to the bottom plate(s)  55  via a third control valve V 3 / 66 , to the Left Air Supply Chamber/ 28  via the first control valve V 1 / 62  and to the Right Air Supply Chamber/ 28  via a second control valve V 2 / 64 . The Section Timing Control  68  can turn each of these valves on and off during each section cycle. 
     When the machine according to the invention is in use, a cycle can be regarded as starting when the mold members are open as shown in  FIG. 2 . Preferably at this stage, the control cylinders V 1 , V 2  will operate to provide cooling air to the chambers  28 , and hence, to the recesses  16  of the four mold members. When cooling air enters the recess  16  of a mold member, it can pass either upwards through upper portions of the cooling passages  14  or downwards through lower portions of the cooling passages  14 . When the mold members  2  are closed about a glass parison, the air supply to the chambers  28  can be stopped, and the third control valve V 3  can be operated to supply cooling air to the outlets  54  in the plate  52  to pass up through the cooling passages  10 ,  14  and  17  of the mold members. When the mold members are opened, this supply of air to all the cooling passages will be turned off and air again can be supplied to the chambers  28  and thence to the recesses  16  and the cooling passages  14 . 
     It has been found that the presence of the recess  16  interrupting the cooling passages  14  does not prevent the usual calculations of the cooling effect in an axially cooled system. Preferably, the extra cooling provided by the chambers  28  is provided for up to about 300 degrees in the cycle. The effect of the extra cooling on the vertical temperature profile in the mold members can be affected as desired by the precise height wise location of the recess  16  in the mold member. 
     The arrangement illustrated in fact allows for very flexible control of the cooling of the blow mold members  2 . While axial cooling from the outlets  54  will take place when the mold is closed, air can be supplied to the recesses  16  of the mold members  2  continuously throughout the whole of the machine cycle if desired. 
     If it is desired, the cooling of the mold can be modified by plugging certain of the air passages. For example, if the vertical profile of the mold temperature is that the bottom of the mold is hotter than the top, more cooling may be achieved by blocking some of the passages  14  extending upwards from the recess  16  while leaving the portion of those passages extending downwards from the recess  16  clear. Thus, more cooling air will be directed downwards from the recess  16  than upwards. 
       FIGS. 4 and 5  show an alternative mold member  102  which may be utilized in the mold mechanism of  FIG. 2  in place of the mold members  2 . It will be understood that certain of the parts of the mold member  102  are indicated by the same numerals as in the mold member  2  of  FIG. 1  where such parts are identical. The mold member  102  differs from the mold member  2  in that, instead of the recess  16 , the mold member  102  comprises a series of generally radial passages  104  which extend from an outer surface  103  of the mold member to longitudinally extending cooling passages  114 , corresponding to the passages  14  of  FIG. 1 . These passages  104  serve as additional means for introducing air into selected cooling passages  114  in the outer array of cooling passages intermediate the ends of those cooling passages.  FIG. 5  shows a cross section of the mold member  102  showing that the passages  104  lie in a plane and all extend at right angles to the cooling passages  114 . 
     In  FIG. 6 , is shown a further modification of the alternative mold member of  FIGS. 4 and 5 . As can be seen, in this modification cooling passages  204  extend from the outer surface  103  of the mold member  103  to the longitudinally extending cooling passages  114 , but instead of lying in a plane, as do the passages  104 , the passages  204  are inclined to the axes of the cooling passages. 
     The construction of the mold members  102  allows for flexible control of the cooling of the blow mold members. Not only do the possibilities of varying the time during the machine cycle for which the additional cooling air is provided, as discussed above in relation to  FIGS. 1 ,  2  and  3 , still exist, but also the angling and positioning of the passages  104  or  204  allow for localizing the cooling in the mold member, thus allowing for example, for the reduction of hot spots in the mold member when in use.