Method and apparatus for restoring the necked-down end of a tubular core

Abstract

A device for restoring a necked-down end of a plastic core includes molding and curing stations and a core handling system having a carriage for sequentially positioning the core adjacent the stations. The molding stations are heated and cooled, respectively, by heating elements and a chilled coolant. A core handling system includes a core-supporting carriage slidably supported on first rails for engagement between the core and the stations. The first rails are slidably supported on perpendicularly oriented second rails to provide for sequential alignment of the carriage with the molding and curing stations. A control system includes motor drives controlled by a programmable logic controller having a processor. Sensors communicate signals to the processor representing the position of the carriage with respect to the upper rails and the position of the upper rails with respect to the lower rails for actuation and control of the motor drives.

What is claimed is:  
     
         1 . An apparatus for restoring a necked-down portion of a tubular plastic core, the apparatus comprising: 
 a molding station defining an annular shaping chamber having at least one surface engageable with the end of a core;    a source of heat operably connected to the molding station to heat the surface of the shaping chamber;    a curing station having a fixation member defining a surface engageable with the end of a core a cooling system operably connected to the curing station to cool the surface of the fixation member;    a core handling system for sequentially positioning the end of a core adjacent the molding station and the curing station, the core handling system comprising a carriage having at least one support member engageable with a core.    
     
     
         2 . The apparatus according to  claim 1  wherein the molding station comprises a stand having opposite front and rear sides and a mold member, the mold member connected to the stand such that it extends from the front side of the stand, the mold member including inner and outer wall portions having surfaces defining the annular shaping chamber.  
     
     
         3 . The apparatus according to  claim 2  wherein the source of heat comprises at least one heating element engaging one of the wall portions defining the annular shaping chamber.  
     
     
         4 . The apparatus according to  claim 3  wherein the source of heat comprises at least one external heating element contacting the outer wall portion and at least one cartridge heater received in a hole formed in the inner wall.  
     
     
         5 . The apparatus according to  claim 1  wherein the curing station comprises a stand having opposite front and rear sides and wherein the fixation member is connected to the stand such that it extends from the front side of the stand.  
     
     
         6 . The apparatus according to  claim 1  wherein the fixation member comprises a wall portion defining the surface, the wall portion further defining a cooling chamber for directing a coolant through the fixation member.  
     
     
         7 . The apparatus according to  claim 1  wherein the core handling system further comprises first rails, the carriage slidably connected to the first rails to provide for engagement and disengagement between the stations and a core supported by the carriage.  
     
     
         8 . The apparatus according to  claim 7  wherein the core handling system further comprises a rail support plate connected to the first rails, the core handling system further comprising second rails oriented perpendicular to the first rails, the rail support plate slidably connected to the second rails for alignment between the stations and a core supported by the carriage.  
     
     
         9 . The apparatus according to  claim 8  wherein the core handling system further comprises a first motor drive connected to the rail support plate for powered translation of the rail support plate with respect to the second rails, the core handling system further comprising a second motor drive secured to the rail support plate, the second motor drive connected to the carriage for powered translation of the carriage with respect to the first rails.  
     
     
         10 . The apparatus according to  claim 1  further comprising a control system including a programmable logic controller, the programmable logic controller having a processor responsive to control signals representing operating parameters for at least one component or system for control by the control system.  
     
     
         11 . A method for restoring a necked-down end of a tubular plastic core, the method comprising the steps of: 
 providing a molding station defining a shaping chamber adapted for receipt of the end of a core, the shaping chamber including at least one surface for engagement with a received core, the molding member adapted for heating of the shaping chamber;    providing a curing station having a fixation member defining a surface adapted for engagement with a shaped end of a core, the curing station adapted for cooling of the fixation member positioning a core adjacent the molding station such that an end of the core is received within the shaping chamber of the molding station for engagement between the core and the shaping surface;    heating the molding station such that the temperature of the core end reaches the softening temperature for the material of the core;    maintaining the end of the core in engagement with the shaping surface for a sufficient time to shape the end of the core against the shaping surface;    disengaging the core from the molding station;    positioning the core adjacent the curing station such that the end of the core engages the surface of the fixation member;    cooling the fixation member of the curing station below an ambient temperature for removal of heat from the end of the core; and    maintaining the end of the core in engagement with the fixation member for a sufficient time to fix the shaped end of the core.    
     
     
         12 . The method according to  claim 11  further comprising the step of providing a core handling system having a carriage adapted for supporting a core, the core handling system further including first and second rails oriented perpendicularly to each other, the carriage being slidably connected to the first rails, the first rails being slidably supported on the second rails, and wherein the carriage is translated with respect to the first rails during the steps of positioning the core adjacent the molding station and disengaging the core from the molding station and further wherein the carriage is translated with respect to the first rails and the first rails are translated with respect to the second rails during the step of positioning the core adjacent the curing station.  
     
     
         13 . The method according to  claim 12  further comprising the step of providing a control system including a programmable logic controller having a processor, and wherein the core handling system further comprises first and second motor drives controlled by the processor to provide for translation of the carriage and translation of the first rails during the steps of positioning the core adjacent the molding station, disengaging the core from the molding station and positioning the step adjacent the curing station.  
     
     
         14 . The method according to  claim 12 , wherein the control system further comprises sensors for determining the position of the carriage with respect to the first rails and the position of the first rails with respect to the second rails, and wherein the sensors communicate signals to the processor representing the position of the carriage and the position of the first rails during the steps of positioning the core adjacent the molding station, disengaging the core from the molding station and positioning the step adjacent the curing station.  
     
     
         15 . A restored plastic core formed according to the method of  claim 11 .  
     
     
         16 . The restored plastic core according to  claim 15 , wherein the core is made from polypropylene.  
     
     
         17 . The restored plastic core according to  claim 15 , wherein the core has a wall thickness of between approximately 0.060 inch and approximately 0.333 inch.  
     
     
         18 . A molding machine for restoring a necked-down end of a plastic tube, the machine comprising: 
 a molding station having inner and outer walls defining an annular shaping chamber adapted for receiving and restoring a necked-down end of a plastic tube;    heating elements received by the inner and outer walls to provide for heating of the annular shaping chamber, the heating elements including at least one external heating element in contact with a surface of the outer wall and at least one heating element received in a hole formed in the inner wall;    a curing station spaced from the molding station, the curing station having a fixation member defining a surface adapted for engagement with a restored end of a necked-down tube, the fixation member defining an annular chamber providing for receipt of a coolant by the fixation member; and    a tube handling system providing for sequential alignment of the necked-down tube with the molding station and the curing station; and    a control system having a programmable logic controller providing for automatic control of the heating elements and for automatic control of the tube handling system.    
     
     
         19 . The molding machine according to  claim 18 , wherein the tube handling system comprises a carriage adapted for support of a necked-down tube and first rails slidably supporting the carriage for movement of the tube towards and away from one of the stations, the tube handling system further comprising second rails slidably supporting the first rails, the second rails being perpendicular to the first rails for aligning the tube with the molding station and the curing station.  
     
     
         20 . The molding machine according to  claim 19 , wherein the carriage includes tube-engaging supports each having upper and lower portions pivotably connected at a pin joint to provide for open and closed conditions of the carriage for loading a necked-down tube, and wherein the control system includes a limit switch adjacent the pin joint of one of the supports to provide a signal to the programmable logic controller representing the condition of the carriage, the control system further including at least one limit switch adjacent each of the first and second rails to provide a signal to the programmable logic controller representing the position of the carriage with respect to the first and second rails, respectively.  
     
     
         21 . A method for restoring a plastic tube cut from a continuous extrusion and having a necked-down end, the method comprising the steps of: 
 providing a heated molding station defining a chamber adapted for shaping an end of a tube received within the chamber;    providing a curing station having a surface adapted for engaging the shaped end of the tube, the curing station defining at least one internal passage for receipt of a chilled coolant;    providing a tube handling system comprising a carriage adapted for supporting a tube, the tube handling system further comprising upper rails slidably supporting the carriage for movement of the carriage towards and away from the stations, the tube handling system further comprising lower rails perpendicular to the upper rails and slidably supporting the upper rails for sequential alignment of the tube with the molding station and curing station, respectively;    providing a drive system comprising a first motor drive for translation of the upper rails with respect to the lower rails and a second motor drive for translation of the carriage with respect to the upper rails, and further providing a control system having a processor for actuation and control of the drive system motors;    placing a tube having a necked-down end in the carriage;    actuating the second motor drive to position the end of the tube in the chamber of the molding station;    actuating the second motor drive to remove the end of the tube from the chamber of the molding station;    actuating the first motor drive to align the carriage with the curing station; and    actuating the second motor drive to provide for engagement of the end of the tube with the surface of the curing station.    
     
     
         22 . The method according to  claim 21  wherein the control system further comprises first and second sets of limit switches adjacent the lower and upper rails, respectively, to generate signals representing the position of the upper rails with respect to the lower rails and the position of the carriage with respect to the upper rails, and wherein the method further includes the step of stopping the second motor drive in response to a signal generated by one of the second limit switches following each of the steps of actuating the second motor drive, and wherein the method further includes the step of stopping the first motor drive in response to a signal generated by one of the first limit switches following the step of actuating the first motor drive.