Abstract:
A mold open and close mechanism uses the hook of a blank mold half and the associated ridges of the upper mold support hanger to maintain the blank mold half on the mold but defines a vertical locating structure for placing the bottom surface of the blank mold half on the top horizontal surface of the lower mold support hanger with a vertical space between the hook of the blank mold half and the upper mold support hanger.

Description:
This invention relates to a mold mechanism at a blank station of an I. S. type glassware forming machine. 
   BACKGROUND OF THE INVENTION 
   In the production of glass containers by the press and blow method on the well known I. S. type machine, a gob of glass is provided to a blank or parison mold comprising two mold members or halves. These mold halves are supported by opposed arms of a mold open and close mechanism at a blank station of the machine, which mold members can be closed to form a mold cavity. The glass in the mold cavity is pressed into the required shape of a parison by a plunger moving upwardly into the mold cavity, a lower portion of the glass being forced into a neck ring of the mold. The plunger is then withdrawn and the parison is carried by the neck ring away from the blank station and is transferred to a blow mold station where it is blown to the required shape. In the blow and blow method a gob of glass is provided to the parison mold and is then blown into the required shape of a parison. The shaped parison is again carried by a neckring away from the blank station to a blow mold station. 
   It will be understood that the mold members must be accurately located, i.e., there must be a datum from which their position is located with respect to other parts of the machine, particularly the plunger mechanism and the neck ring mechanism. Customarily each mold arm is made up of upper and lower hanger members and the mold halves include downwardly depending hooks which hang on these members with the location of the horizontal surface where the hook is supported defining the datum for the mold. Normally the hooks are located at the top of the mold half but GB 2175296 shows a variant construction in which the mold member has its vertical position determined by a lower hanger member. 
   Accurate location of the mold members is of course also required when one set of mold members is exchanged for another set of different size. Conventionally this is done by substituting the hanger members used with one set of molds by hanger members appropriate for the new set of molds. Such hanger members are fairly expensive, and what is more, if the mold arms are optimally positioned to close the molds with pressure applied to upper and lower end portions of the mold members in the case of mold members of one size, on substitution of the hanger members for another size of mold member the mold arms will no longer be so optimally positioned. This can allow for springing of the molds and the formation of seams on the container being made. 
   OBJECT OF THE INVENTION 
   It is accordingly an object of the present invention to provide a datum for the molds that will assure that the bottom face of the molds will engage the top face of the support as the bottom surface of the mold wears away to thereby assure that any cooling interconnections therebetween will have maximum efficiency throughout its use. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the accompanying drawings: 
       FIG. 1  shows a mold mechanism at a blank station of a double gob glassware forming machine with some parts omitted and with a pair of mold halves in the mechanism; 
       FIG. 2  shows a view similar to  FIG. 1  but viewed from the other side of the mold mechanism; 
       FIG. 3  shows a view of an upper portion of an air chamber member; 
       FIG. 4  shows a view of a lower portion of an air chamber member; and 
       FIG. 5  is a diagrammatic sketch of how a mold half is supported by the upper and lower mold hangers. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   A multi gob glassware forming machine, specifically a double gob machine comprises a mold mechanism,  FIGS. 1 &amp; 2 , mounted on a table  3  of the machine at a blank station of the machine. The mold mechanism comprises a pivot  2  fixed in the machine and two mold arms  4 , 6 , mounted on the pivot  2  and adapted to support two blank molds, only one,  8 , of which is shown in an open condition in  FIG. 1 . The blank mold  8  comprises two mold members  10 , 12 , which are generally cylindrical in shape and each of which has straight cooling passages  14  extending axially through the mold member from a lower end face  16 , 18  to an upper end face  20 , 22  of the mold members. It can be seen that the lower end faces  16 ,  18  bound a recess  17 ,  19  extending round an outer face of a lower end portion of the mold members, and the cooling passages  14  open into the recesses  17 ,  19  when the mold members are in position. It will be understood that the mechanism illustrated is adapted to have two blank molds, i.e. four mold members, and that the mold members are all similar as are the means for supporting the mold members in the mold mechanism. While the mold open and close mechanism is illustrated in the double gob configuration, it could also be single or double gob. 
   The mold arm  4  supports, on a generally vertical support rod  23 , an upper mold support  24 , and a spacer  26  which determines the height of the upper mold support  24  with respect to the mold arm  4 . The upper mold support  24  comprises two curved ridges  28 , only one of which can be seen in  FIG. 1 . The corresponding hook or curved ridge  30  on the mold member will be located behind the curved ridge when the mold is in place. A block  32  secured to the support  24  engages with a corresponding slot (shown at  34  on the mold member  12 ) in the mold member  10  accurately to locate the mold member  10  in position on the support  24 . 
   The mold arm  4  also supports on the rod  23  a lower mold support  36  and a spacer  38  between the mold support  36  and the arm  4  which determines the height of the lower mold support  36  with respect to the mold arm  4 . The lower mold support  36  defines an air plenum chamber  39  for the supported mold halves and serves not only to supply cooling air to the mold supported mold half but also to vertically locate the lower end portion of the mold member. The air chamber member  39  comprises an upper member  46  and a lower member  50  secured together by bolts  58  through holes  52  in the member  46  and  54  in the member  50 . The lower member  50  is recessed and comprises two air inlets  60  and  62 . The inlet  60  leads into a recess  64 , the inlet  62  leads into a recess  66  separated from the recess  64  by a wall  68 . The two members  46  and  50  when secured together provide two plenum chambers. By a plenum chamber we mean a chamber in which the entry to the chamber is sufficiently spaced from the exits to the chamber that a substantially uniform pressure is provided at the exits. The upper member  46  comprises two generally semicircular vertical surfaces  40  which are to be proximate the side wall of a supported mold. These vertical surfaces  40  are adjacent two horizontal supporting surfaces  42 . The surfaces  42  are flat and generally semicircular in plan and have a series of curved apertures  44  formed in them which open into the plenum chambers formed by the recesses  64  and  66  and which are adapted to correspond with the cooling passages of the mold members, i.e. the passages  14  of the mold member  10  opening into the end face  16 . When the mold member  10  is in position as shown in  FIG. 5 , it is positively located by the lower mold support. The chamber member  39  enters the recess  17 , the bottom mold surface or face  16  engages the horizontal support surface  42 , and the vertical surfaces  40  engage the outer circumference of the mold member. The apertures  44  are positioned so that they will be in communication with the lower ends of the cooling passages in the mold member. The hook  30  is spaced vertically from the ridge and upper support  24  and accordingly is not supported by the upper support. The mold is supported vertically at the bottom of the mold where the horizontal bottom surface of the mold  16  rests on the horizontal supporting surface of the upper portion  46  of the lower support. 
   It should be noted that when the machine is inactive and cold, the lower end faces  16  of the mold members may be slightly spaced away from the supporting surfaces  42 , but on use of the machine the mold members get hot and expand, and the supporting surfaces  42  and the end faces  16  then come into contact. Further, as the machine is used, wear can occur between adjacent horizontal surfaces without interfering with the desired mating engagement between surfaces  40  and  16 . The vertical dimension of spacers  26  and  38  are selected to locate these surfaces in engagement. 
   The upper member  46  has an aperture  70  which meets a corresponding aperture  72  in the lower member  50 , and the support rod  23  passes through the apertures  70  and  72  to support the chamber member  39  against the spacer  38 . The inlets  60 , 62  to each plenum chamber are connected by flexible air supply tubes  74  to air control cylinders  76 ,  76 . Another cylinder  76  (not clearly shown) also support a manifold  78  which is also connected to a neck-ring cooling head  80  which directs cooling air onto a neck-ring mechanism  82  of the parison forming mechanism (only shown diagrammatically). 
   The mechanism according to the invention offers improved control over mold cooling. A separate adjustable air control in each air control cylinder  76  controls the supply of cooling air to the neck-ring cooling and to each of the plenum chambers independently. In general, in a blank mold mechanism, the molds near the mold pivot become hotter when the machine is in use than those further away from the pivot, and in the present construction the supply of cooling air to the two mold members can be adjusted to allow for this. 
   If it is desired to change the height of the mold member in the machine, the position of the mold member can be adjusted by choosing spacers  26 ,  38  of appropriate size. Such spacers, being effectively simple collars, are much less expensive than the mold hangers generally in use. Further it is possible to ensure that the clamping forces exerted on the mold members by the mold arms  4 , 6 , are located near the end portions of the mold members. In other arrangements, a large mold member my have to extend upwards beyond the mold arms, thus leading to less effective clamping. When the mechanism of the present invention is in use, the bottom of the mold members are located on the lower mold support whatever expansion of the mold members because of heat may take place.