The present invention relates to I.S. (individual section) machines for manufacturing glass containers, and specifically, to vacuum valves used in conjunction with the process for forming the glass bottles in these machines.
An I.S. machine has a plurality of identical sections each of which has a blank station which receives one or more gobs of molten glass and forms them into parisons and a blow station which receives the parisons and forms them into bottles. The blow station includes a mold, including a pair of opposed side molds. The side molds are first separated to an open position so that a formed parison can be located in the blow station. The side molds are then displaced to the closed position clamping a mold bottom in the process. A blowhead is then located on top of the closed side molds to close the mold and when the parison has completed “reheat”, the blowhead blows the parison into a bottle. A number of small holes are defined in the mold so that a vacuum can be applied between the outer wall of the parison and the mold surface. As the parison is blown, the vacuum draws the air, in this decreasing volume, out of the mold. In a conventional vacuum valve, a constant vacuum is applied.
It is an object of the present invention to improve upon this process for removing air from the blow molds during the bottle forming process.
Other objects and advantages of the present invention will become apparent from the following portion of this specification and from the accompanying drawings that illustrate in accordance with the mandate of the patent statutes a presently preferred embodiment incorporating the principles of the invention.
Referring to the drawings:
The blow station of an I.S. machine includes a blow mold 10 for each parison 12 delivered to the station. A blow mold is defined by a pair of opposing sides 14 and a bottom plate 16. The finish portion 17 of the parison 12 (which was fully defined in the prior blank station) is supported within the opening at the top of the closed mold sides and the top opening of the mold is closed by a blow head 18 which is supplied with air under pressure via a blow valve BV/20. The surface 22, defined on the inside of the mold, defines the bottle that will be formed when the parison is “blown”. Located about this surface are a number of vacuum holes 24 which communicate with a vacuum inlet 25 in the base. The inlet communicates via piping 26 to a Vacuum Valve (VV/28) which communicates with a suitable source of Vacuum 30. A pair of vacuum control valves (VCV1/29, VCV2/32) are operatively associated with the Vacuum Valve 28.
Referring to
A control valve 50 is defined between the on-off valve 44 and the vacuum valve outlet 42 by locating an annular valve seat 52, with a beveled surface, into valve body passage 54 and having a matched needle valve or operator 56 displaceable between an up, fully open position and a down position, which will partially close the control valve to a desired degree. A needle valve collar 66 captures a compression spring 68 so that the neutral position of the control valve will be the up position. By operating the second vacuum control valve (VCV2/32), air under pressure from a suitable source, is applied to the top of the collar, to displace the needle valve to its down position. As shown, the top of the needle valve shaft 60 is threaded 62 and the desired down position will be set by adjusting the associated nut 64.
The control for the vacuum valve is illustrated in