# US 9,038,420 B2 · Dwell time control system and method with automatic pressure switch point adjustment > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,038,420 B2 - Document ID: US9038420B2 - Status: Granted - Kind: B2 - Application number: 14/057,353 - Filed: 2013-10-18 - Published: 2014-02-13 - Granted: 2015-05-26 - Earliest claimed: 2011-09-14 - Assignees: Emhart Glass S.A. - Applicants: Emhart Glass S.A. - Inventors: Andreas Helfenstein; Hartmut Geisel; Christian Fröba - Web page: https://patentgrep.com/patent/US9038420B2 ## CPC - C03B 9/1932: {Details of such machines, e.g. plungers or plunger mechanisms for the press-and-blow machine, cooling of plungers (C03B9/195 takes precedence)} - C03B 9/1936: {Hydraulic or pneumatic displacement means of the plunger} - C03B 9/41: Electric or electronic systems (in general G05B19/00) - C03B: MANUFACTURE, SHAPING, OR SUPPLEMENTARY PROCESSES ## Abstract A dwell time control system and method for automatically adjusting the selection and timing of a sequence of pressures used to drive the plunger in a parison mold during the parison forming process. The timing of characteristics of the observed press curve from one or more previous parison forming cycles are ascertained and used to control the timing of the changes in pressure during a subsequent parison forming cycle. The timings of these changes of pressure are determined as predetermined percentages of the timings of the characteristics in order to prevent the blow mold from being forced open and in order to prevent the occurrence of an overpressed finish. ## Claims ### Claim 1 A system for operating a plunger for molding a parison in a blank mold, the plunger being driven by a piston in a cylinder to which a source of a pressurized medium may be applied at selected pressures, the system comprising: a position sensor that monitors the position of the plunger in the blank mold versus time during at least one parison forming cycle beginning at a time t1 and ending at a time t4; and a control system programmed to detect a first characteristic of the movement of the plunger at a time t2 during the at least one monitored parison forming cycle and a second characteristic of the movement of the plunger at a time t3 in the at least one monitored parison forming cycle; wherein the control system is also programmed to determine a time tp2 before t2 based on time t2 and to determine a time tp3 before t3 based on time t3; and wherein the control system is further programmed to apply a first pressure from time t1 to time tp2, a second pressure from time tp2 to time tp3, and a third pressure from time tp3 to time t4 during a parison forming cycle subsequent to the at least one monitored parison forming cycle, after a gob is loaded into the blank mold. ### Claim 2 (depends on 1) A system as defined in claim 1, wherein the control system is configured such that the first characteristic of the movement of the plunger that the control system is configured to detect comprises: a nonlinearity detected by the control system in the movement of the plunger with respect to time which is indicative of an upper part of the mold having been filled with glass from the glass gob. ### Claim 3 (depends on 1) A system as defined in claim 1, wherein the control system is configured such that the first characteristic of the movement of the plunger that the control system is configured to detect at the time t2 is the upper part of the mold having been filled with glass from the glass gob. ### Claim 4 (depends on 1) A system as defined in claim 1, wherein the control system is configured such that the second characteristic of the movement of the plunger that the control system is configured to detect comprises: a movement-related characteristic of the plunger detected by the control system that falls below a preselected level which is indicative of the glass from the glass gob having been distributed throughout the entire blank mold to completely fill it. ### Claim 5 (depends on 1) A system as defined in claim 1, wherein the control system is configured such that the second characteristic of the movement of the plunger that the control system is configured to detect at time t3 is the glass from the glass gob having been distributed throughout the entire blank mold to completely fill it. ### Claim 6 (depends on 1) A system as defined in claim 1, wherein the control system is configured to apply the first pressure being larger than either the second pressure or the third pressure. ### Claim 7 (depends on 6) A system as defined in claim 6, wherein the control system is configured to apply the second pressure being greater than the third pressure. ### Claim 8 (depends on 6) A system as defined in claim 6, wherein the control system is configured to apply the third pressure being greater than the second pressure. ### Claim 9 (depends on 1) A system as defined in claim 1, wherein the position sensor is configured to monitor the position of the plunger in the blank mold versus time during each parison forming cycle beginning at a time t1 and ending at a time t4. ### Claim 10 (depends on 9) A system as defined in claim 9, wherein the control system is programmed to further detect the point in time during more than one monitored parison forming cycle at which the movement of the plunger in the blank mold with respect to time exhibits a non-linearity that is indicative of an increase in resistance to further movement of the plunger, that point in time being the time t2; and wherein the control system is programmed to further detect the point in time during more than one monitored parison forming cycle at which the movement of the plunger in the blank mold with respect to time falls below a minimum threshold indicative of the end of a pressing cycle, that point in time being the time t3. ### Claim 11 (depends on 10) A system as defined in claim 10, wherein the control system is configured to average the times t2 during the more than one monitored parison forming cycle to determine the time t2 for the parison forming cycle subsequent to the more than one monitored parison forming cycles. ### Claim 12 (depends on 11) A system as defined in claim 11, wherein the control system is configured to average the times t2 during eight monitored parison forming cycles to determine the time t2 for the parison forming cycle subsequent to the eight monitored parison forming cycles. ### Claim 13 (depends on 10) A system as defined in claim 10, wherein the control system is configured to average the times t3 during the more than one monitored parison forming cycle to determine the time t3 for the parison forming cycle subsequent to the more than one monitored parison forming cycles. ### Claim 14 (depends on 13) A system as defined in claim 13, wherein the control system is configured to average the times t3 during eight monitored parison forming cycles to determine the time t3 for the parison forming cycle subsequent to the eight monitored parison forming cycles. ### Claim 15 (depends on 1) A system as defined in claim 1, wherein the control system is configured to calculate the time interval between time t1 and time tp2 to be a first predetermined percentage of the time interval between time t1 and time t2 for the at least one monitored parison forming cycle; and wherein the control system is configured to calculate the time interval between time t1 and time tp3 to be a second predetermined percentage of the time interval between time t1 and time t3 for the at least one monitored parison forming cycle. ### Claim 16 (depends on 15) A system as defined in claim 15, wherein the control system is configured to calculate the time interval between time t1 and time tp2 to be eighty percent of the time interval between time t1 and time t2 for the at least one monitored parison forming cycle. ### Claim 17 (depends on 15) A system as defined in claim 15, wherein the control system is configured to calculate the time interval between time t1 and time tp3 to be seventy percent of the time interval between time t1 and time t3 for the at least one monitored parison forming cycle. ### Claim 18 (depends on 1) A system as defined in claim 1, wherein the control system is programmed to adjust either the second pressure or both the first pressure and the second pressure to achieve a desired dwell time interval between the time t3 and the time t4. ### Claim 19 A system for operating a plunger in a blank mold to mold a parison from a glass gob, the plunger being driven by a piston in a cylinder to which a source of a pressurized medium may be applied at selected pressures, the system comprising: a position sensor configured to monitor the position of the plunger in the blank mold versus time during a parison forming cycle beginning at a time t1 and ending at a time t4; and a control system programmed to detect a nonlinearity in the movement of the plunger during the monitored parison forming cycle that is indicative of an upper part of the blank mold having been filled with glass from the glass gob at a time t2; wherein the control system is programmed to detect a movement-related characteristic of the plunger during the monitored parison forming cycle that falls below a preselected level at a time t3, the movement related characteristic falling below the preselected level being indicative of the glass from the glass gob having been distributed throughout the blank mold to fill the blank mold; and wherein the control system is programmed to apply a first pressure from time t1 to time tp2, a second pressure from time tp2 to time tp3, and a third pressure from time tp3 to time t4 during a parison forming cycle subsequent to the monitored parison forming cycle, after a gob is loaded into the blank mold; wherein the control system is programmed to determine the time interval between time t1 and time tp2 to be a first predetermined percentage of the time interval between time t1 and time t2; and wherein the control system is programmed to determine the time interval between time t1 and time tp3 to be a second predetermined percentage of the time interval between time t1 and time t3. ### Claim 20 A system for operating a plunger in a blank mold to mold a parison from a glass gob, the plunger being driven by a piston in a cylinder to which a source of a pressurized medium may be applied at selected pressures, the system comprising: a position sensor configured to monitor the position of the plunger in the blank mold versus time during parison forming cycles each beginning at a time t1 and ending at a time t4; and a control system programmed to determine a time t2 in each monitored parison forming cycle at which an upper part of the mold has been filled with glass from the glass gob; wherein the control system is programmed to determine a time t3 in each monitored parison forming cycle at which the glass from the glass gob has been distributed throughout the entire blank mold to completely fill it; and wherein the control system is programmed to apply a first pressure from time t1 to time tp2, a second pressure from time tp2 to time tp3, and a third pressure from time tp3 to time t4 during each parison forming cycle, after a gob is loaded into the blank mold; wherein the control system is programmed to determine the time interval between time t1 and time tp2 to be a first predetermined percentage of a time interval based upon the time interval between time t1 and time t2 for one or more previous parison forming cycles; and wherein the control system is programmed to determine the time interval between time t1 and time tp3 to be a second predetermined percentage of a time interval based upon the time interval between time t1 and time t3 for one or more previous parison forming cycles.