The invention relates to post-mold cooling of articles, such as injection molded preforms.
The injection molding of preforms is well known. It is also known to remove preforms from the mold in a partially cooled state and subsequently cool them in automatic handling equipment designed to remove residual heat from both their external and internal surfaces. Prior art examples of said automatic handling equipment are discussed below.
US 2016/0200012, entitled “Post-Mold Cooling Method and Apparatus with Cyclone Cooling Effect,” teaches an annular spiral inducing flow element that enhances the cooling effect of a fluid cooling stream passing through the interior of a preform. This document also teaches that suction can be used, instead of or in addition to positive pressure, to impart motion to the cooling air. This can be done with or without sealing the preform to the plate. This application is owned by the present Applicant and is incorporated herein by reference.
U.S. Pat. No. 6,171,541, entitled “Preform Post-Mold Cooling Method and Apparatus,” teaches a cooling pin inserted into a preform held in a cooling tube and applying a flow of cooling fluid directly to the internal dome portion of the preform via the tip portion of a cooling pin. Different configurations of the cooling tube geometry are shown and the use of vacuum to remove the molded article from the cooling tube is also taught. This document teaches providing a separate channel and vacuum source for removing the cooling air from the interior of the molded article.
U.S. Pat. No. 6,475,422, entitled “Preform Post-Mold Cooling Method and Apparatus,” teaches removing cooled molded articles from carrier plate by applying a vacuum to the cooled mold articles via cooling pins and moving a frame relative to the carrier plate.
U.S. Pat. No. 4,592,719, entitled “Apparatus for Manufacturing Plastic Bottles from Molded Hollow Preforms,” teaches a cooling pin that uses a vacuum to draw atmospheric cooling air through the open end of the preform held in a cooling tube. The warmed air is exhausted via the tubular cooling pin and conduit in the mounting frame. The tip of the cooling tube touches the dome portion of the preform and thereby spaces the top sealing surface (TSS) of the preform away from the frame surface thereby creating an inlet for the cooling air to enter the interior of the preform.
EP 0937566, entitled, “Cooling and Removal System for Injection Moulded Hollow Bodies,” teaches a cooling pin having the capability to create a vacuum inside the respective preform in order to suck it onto the nozzle itself or to give off a jet of compressed air to expel the preform.
The invention uses a hollow sliding cooling pin to supply or remove a flow of cooling fluid through the interior space of a preform while its exterior surface is being cooled in a cooling tube. The sliding pin is moved toward the preform by a biasing mechanism in the frame and is moved away from the preform by contact with an exterior surface of the preform or the cooling tube. The sliding cooling pin is automatically connected to a source of vacuum or fluid pressure or is blocked from the source of vacuum or fluid pressure by the sliding action of the sliding cooling pin.
According to an aspect of the invention, an apparatus includes a cooling pin to slidably extend from a frame and to be inserted into an injection molded article. The cooling pin is hollow to allow for flow of cooling fluid through the cooling pin. The cooling pin has a hole to be in fluid communication with a source of vacuum to draw cooling fluid within the injection molded article into the cooling pin. The cooling pin has a first position with respect to the frame, the first position to allow flow of cooling fluid through the hole. The cooling pin has a second position with respect to the frame, the second position to shut off flow of cooling fluid into the cooling pin.
The cooling pin may have a third position with respect to the frame, the third position to shut off the source of vacuum at the hole.
The apparatus may further include a biasing mechanism coupled to the cooling pin, the biasing mechanism to bias the cooling pin away from the second position and towards the third position.
The apparatus may further include a biasing mechanism coupled to the cooling pin, the biasing mechanism to bias the cooling pin towards the injection molded article to eject the injection molded article off the cooling pin.
The biasing mechanism include a spring.
Vacuum applied at the hole of the cooling pin may hold the cooling pin in the second position and may hold the injection molded article with respect to the cooling pin.
The second position of the cooling pin may seal an open end of the injection molded article closed to block intake of cooling fluid into the injection molded article and the cooling pin.
The apparatus may further include a spiral-flow inducing annular element slidable with the cooling pin. The spiral-flow inducing annular element may provide cooling fluid into the injection molded article in the first position and may block intake of cooling fluid into the injection molded article in the second position.
The cooling pin may have a plurality of holes including the hole.
The injection molded article may be an injection molded preform.
These and other aspects of the invention are disclosed in detail below.
The apparatuses discussed herein include a sliding cooling pin. Such a sliding cooling pin and related components may be included in a cooling apparatus for injection molding. For example, an array of such sliding cooling pins may be installed at a plate that is used to carry and/or cool a plurality of preforms. Such a sliding cooling pin and related components may be installed at an injection molding machine.
A spiral-flow inducing annular element 50 is fastened to the cooling pin 30 at shoulder location 52. The spiral-flow inducing element 50 comprises two concentric annular tubes, an inner tube 54 that fits tightly around the cooling pin 30, and an outer tube 56 that is spaced from and connected to the inner tube 54 by contoured fins or blades 58 which are configured to induce a spiral flow to a cooling fluid stream 60 that passes therethrough. An anti-rotation device comprising slot 33 in holder 32 and pin/key 35 fastened to cooling pin 30 prevent cooling pin 30 from rotating. Absent said anti-rotation device the incoming cooling fluid stream 60 acting on said contoured fins or blades 58 would cause the cooling pin 30 to rotate and thereby reduce effectiveness of the induction of spiral-flow to cooling fluid stream 60. Pin/key 35 slides within slot 33 as the cooling pin 30 slides within holder 32.
The enhanced cooling effects and benefits of said spiral flowing fluid cooling stream are explained in the co-pending US Patent Application Publication US 2016/0200012, entitled “Post-Mold Cooling Method and Apparatus with Cyclone Cooling Effect.” The spiral-flow inducing annular element 50 is may be a monolithic component that can be injection molded as a whole using a suitable material. The diameter of the annular element 50 is sized such that its outer diameter substantially matches the outer diameter of the neck finish 62 of the preform 10.
In operation, the cooling pin/frame assembly and preform/cooling tube assembly are moved together in order to introduce the cooling pin 30 into the preform's interior space. During this movement the top sealing surface (TSS) 64 of the preform 10 makes contact with the outer tube 56 of the annular element 50 and continuing movement causes the cooling pin 30 to slide within its holder 32 until a fluid conduit connection is made between the transverse holes 44 and the conduit 46 in the holder and frame thereby initiating a flow of ambient cooling fluid flow 60 through the spiral inducing annular element 50 to the open end 36 of the cooling pin 30 and out via the conduit 46 in the frame. The cooling pin 30 is biased toward the preform 10 by a spring 66, for example, that surrounds the shoulder screw 40. Alternate biasing mechanism, such as an air cylinder, etc. can also be used. The relative movement between the cooling pin/frame assembly and the preform/cooling tube assembly is stopped before the outer tube 56 touches the shoulder 32 which would block the flow of ambient air being induced. A suitable gap between the outer tube 56 and shoulder 32 is established by trial and error to optimize the flow rate of the ambient air being induced.
In further operation the cooling pin/frame assembly and preform/cooling tube assembly are moved apart thereby completely withdrawing the preform 10 from the cooling tube 12. The preform 10 is firmly held against the outer element 56 by virtue of the vacuum inside the preform.
Using a sliding cooling pin to automatically connect and disconnect to a vacuum source saves the cost of providing some of the expensive valve and control hardware for the handling equipment. The automatic operation of the valving caused by the relative movement of the cooling pin and the preform by way of contact between them or the preform's cooling tube simplifies timing and control of the process, thereby saving cost when setting up the process.
A coaxial annular element 100 is fastened to the cooling pin 130 at shoulder location 152. The annular element 100 comprises two concentric annular tubes, an inner tube 154 that fits tightly around the cooling pin 130, and an outer tube 156 that is spaced from and connected to the inner tube 154 by radial webs or blades 158 which allow the cooling fluid stream 147 to pass therethrough. The diameter of the annular element 100 is sized such that it's outer diameter substantially matches the outer diameter of the neck finish 162 of the preform 110.
In operation, the cooling pin/frame assembly and preform/cooling tube assembly are moved together in order to introduce the cooling pin 130 into the preform's interior space. During this movement the top sealing surface (TSS) 164 of the preform 110 makes contact with the outer tube 156 of the annular element 100 and continuing movement causes the cooling pin 130 to slide within its holder 132 until a fluid conduit connection is made between the transverse holes 144 and the conduit 146 in the holder and frame thereby initiating a flow of pressurized cooling fluid flow 148 through the interior of the preform to its open end and out via the annular element 100 to atmosphere. The cooling pin 130 is biased toward the preform 110 by a spring 166, for example, that surround the shoulder screw 140. Alternate biasing mechanism, such as an air cylinder, etc. can also be used. The relative movement between the cooling pin/frame assembly and the preform/cooling tube assembly is stopped before the outer tube 156 touches the shoulder 132 which would block the flow to atmosphere. A suitable gap between the outer tube 156 and shoulder 132 is established by trial and error to optimize the flow rate of the pressurized cooling fluid flow 148.
In further operation, the cooling pin/frame assembly and preform/cooling tube assembly are moved apart thereby completely withdrawing the preform 110 from the cooling tube 112. The preform 110 is firmly held against the outer element 156 by virtue of the vacuum inside the preform.
Using a sliding cooling pin to automatically connect and disconnect to both pressurized and vacuum sources saves the cost of providing some of the expensive valves and control hardware for the handling equipment. The automatic operation of the valving caused by the relative movement of the cooling pin and the preform by way of contact between them or the preform's cooling tube simplifies timing and control of the process, thereby saving cost when setting up the process.
A spiral-flow inducing annular element 250 is fastened to the cooling pin 230 at shoulder location 252. The spiral-flow inducing element 250 comprises two concentric annular tubes, an inner tube 254 that fits tightly around the cooling pin 230, and an outer tube 256 that is spaced from and connected to the inner tube 254 by contoured fins or blades 258 which are configured to induce a spiral flow to a cooling fluid stream 260 that passes therethrough. An anti-rotation device is included in the configuration as described above in the first embodiment.
The enhanced cooling effects and benefits of said spiral flowing fluid cooling stream are explained in the co-pending US Patent Application Publication US 2016/0200012, entitled “Post-Mold Cooling Method and Apparatus with Cyclone Cooling Effect”. The spiral-flow inducing annular element 250 also includes a circular base 290 that is sized to slidably fit within cylinder 292 that is incorporated in holder 232. Circular base 290 is attached to the inner tube 254 and is spaced from the lower side of the contoured fins or blades 258 thereby created an annular conduit 294 through which cooling fluid stream 260 flows from port 296 in the sidewall of holder 232. Element 250 may be a monolithic component that can be injection molded as a whole using a suitable material. However, spiral inducing elements 258, 254, 256 and circular base 290 could be an assembly of separate components and/or could be attached separately to the cooling pin 230 individually. The diameter of the annular element 250 is sized such that its outer diameter substantially matches the outer diameter of the neck finish 262 of the preform 210.
In operation, the cooling pin/frame assembly and preform/cooling tube assembly are moved together in order to introduce the cooling pin 230 into the preform's interior space. During this movement the top sealing surface (TSS) 264 of the preform 210 makes contact with the outer tube 256 of the annular element 250 and continuing movement causes the cooling pin 230 to slide within its holder 232 until a fluid conduit connection is made between the transverse holes 244 and the conduit 246 in the holder and frame thereby initiating venting of a pressurized flow of cooling fluid 260 through the spiral inducing annular element 250 to the open end 236 of the cooling pin 230 and out via the conduit 246 in the frame. Simultaneously annular conduit 294 is aligned with port 296 thereby allows pressurized cooling fluid flow 260 to commence. The cooling pin 230 is biased toward the preform 210 by a spring 266, for example, that surrounds the shoulder screw 240. Alternate biasing mechanism, such as an air cylinder, etc. can also be used.
The relative movement between the cooling pin/frame assembly and the preform/cooling tube assembly is stopped at a suitable position to optimize the flow rate of the pressurized cooling fluid flow 260.
In further operation, the cooling pin/frame assembly and preform/cooling tube assembly are moved apart thereby completely withdrawing the preform 210 from the cooling tube 212. The preform 210 is firmly held against the outer element 256 by virtue of the vacuum inside the preform.
Using a sliding cooling pin to automatically connect and disconnect to vacuum and pressurized fluid source saves the cost of providing some of the expensive valve and control hardware for the handling equipment. The automatic operation of the valving caused by the relative movement of the cooling pin and the preform by way of contact between them simplifies timing and control of the process, thereby saving cost when setting up the process.
A cooling pin 430 is slidably mounted in a holder 432, which can be mounted to a frame, plate, or other structure. The cooling pin 430 can be inserted into the interior space of the preform 410 while the preform 410 is inside a cooling tube. The cooling pin 430 comprises a hollow tube 442 with a first end 436 that is open and that does not touch the interior surface of the preform 410. The opposed end 438 of the cooling pin 430 is closed. The hollow tube 442 terminates near the end 438 at one or more openings 444 that are in fluid communication with a conduit 446 that passes through holder 432 and that is connected to a controllable source of vacuum.
A spiral-flow inducing annular element 450 is fastened to the cooling pin 430 at shoulder location 452. The spiral-flow inducing element 450 comprises one or more spiral channels 458 configured to induce a spiral flow to a cooling fluid stream that passes therethrough. An entrance 454 to the spiral channel 458 is located on a surface of the annular element 450 facing a surface of the holder 432. An anti-rotation device may be provided to prevent the cooling pin 30 from rotating with respect to the holder 432.
The annular element 450 may have a stepped diameter, such that a neck finish 462 of the preform 410 fits over a narrower portion of the annular element 450 and abuts a shoulder 463 that defines the transition to a wider portion of the stepped diameter.
A spring 466, or other biasing mechanism, is provided to the end 438 of the cooling pin 430 away from the preform 410. The spring 466 connects the end 438 of the cooling pin 430 to an end 440 of the holder 432 and biases the cooling pin 430 in a direction towards the preform 410. For example, the end 438 of the cooling pin 430 is positioned within an opening in the end 440 of the holder 432, and the spring 466 engages with a groove on an outside surface of the end 438 of the cooling pin 430 and with an inside groove of the end 440 of the holder 432.
Other biasing mechanism, such as an air cylinder, etc. can be used in addition to or instead of the spring 466. The spring 466 or other biasing mechanism may be positioned at different locations. The spring 466 may be sufficient to provide for anti-rotation of the cooling pin 430 and an additional anti-rotation device may be omitted.
In operation, the cooling pin 430 is introduced into the preform's interior space by relative movement of the preform 410 to the holder 432. The neck finish 462 of the preform 410 fits over the narrower diameter of the annular element 450 and the open end 464 of the preform 410 may contact the shoulder 463 of the annular element 450. Further movement of the preform 410 towards the holder 432 causes the cooling pin 430 to slide within the holder 432, against the spring 466, until a fluid connection is made between the holes 444 in the cooling pin 430 and the vacuum conduit 446 in the holder 432, as shown in
Further urging of the preform 410 towards the holder 432, against the spring 466, causes the annular element 450 to abut a surface of the holder 432 thereby obstructing the intake of cooling fluid at the entrance 454 of the spiral channel 458, as shown in
When vacuum at conduit 446 is shut off, resistance against expansion of the spring 466 ceases. The spring 466 expands, thereby sliding the cooling pin 430 away from its holder 432, as shown in
Further, the end 438 of the cooling pin 430 moves into a position that blocks the conduit 446, so that vacuum can be reapplied to the conduit 446 without drawing cooling fluid through the hollow tube 442, until another preform 410 is positioned on the cooling pin 430 and the cooling pin 430 is pushed back into the position shown in
In addition, although spiral or cyclone-type cooling fluid flow is described in the above, it should be apparent that other types of flow are also contemplated to be suitable. The annular elements and related structures discussed herein need not be limited to those that provide spiral or cyclone cooling fluid flow.
This application claims the benefit of U.S. 62/488,369, filed Apr. 21, 2017, and U.S. 62/501,521, filed May 4, 2017, both of which are incorporated herein by reference.
Number | Date | Country | |
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62501521 | May 2017 | US | |
62488369 | Apr 2017 | US |