KR20070018048A - Non-return valve for use in a molding system - Google Patents

Abstract

The present invention relates to a non-return valve that can be configured for use anywhere along a molding material flow path in a molding system. The non-return valve of the present invention includes improved means for limiting the backflow of the melt therethrough during injection. In particular, the spigot seal is configurable during injection, between complementary male and female spigot portions, which are constructed between complementary valve members, overlapping, closely spaced and parallel to each other. The spigot seal advantageously maintains an effective backflow restriction even during sudden transitional movements between the spigot during injection. Preferably, the non-return valve of the present invention is also configured to include means for aligning and / or guiding complementary valve components with one another to ensure proper alignment between complementary spigots and when the face seal is present, It may also play a role in improving function and lifespan. The non-return valve of the present invention provides a particularly advantageous use when it is configured for use in a barrel assembly of an injection unit during injection molding of a metal alloy.

Forming system, non-return valve, ring member, back flow, spigot

Description

Non-return valve for use in molding systems {NON-RETURN VALVE FOR USE IN A MOLDING SYSTEM}

The present invention relates to a non-return valve that can be configured for use anywhere along the molding material flow path of a molding system. More specifically, the non-return valve of the present invention may be configured for use in a barrel assembly of an injection molding machine. In particular, the non-return valve of the present invention may be configured for use in an injection molding system for the molding of metals.

The structure and operation of the present invention improve the functionality and durability of non-return valves configured for use in barrel assemblies of injection molding systems for the formation of metal alloys such as those of magnesium in a semi-solid (ie thixotropic) state. This will be explained below. Detailed descriptions of the structure and operation of some such injection molding systems may be obtained with reference to US Pat. Nos. 5,040,589 and 6,494,703. Notwithstanding the foregoing, it is not intended to impose this limitation on the general use of the non-return valves of the invention and on their compatibility with other metal alloys (eg, aluminum, zinc, etc.).

1 and 2, an injection molding system as described above is shown.

As is generally known, the injection molding system 10 includes an injection unit 14 and a clamp unit 12 that are coupled to each other. The function of the injection unit 14 is for treating the solid metal feedstock, not shown, with its melt and for subsequent injection of the melt into a closed and clamped injection mold arranged in fluid communication with each other. The injection mold is shown in an open configuration that includes complementary mold hot and cold halves 23, 25. The injection unit 14 further includes an injection unit base 28 for slidably supporting an injection assembly 29 mounted thereon. The injection assembly 29 is provided with a valve assembly 38 for operation (ie, rotation and reciprocation) of the barrel assembly 38 arranged inside the carriage assembly 34 and the screws 56 arranged inside the barrel assembly 38. Directly behind the drive assembly 36 mounted to the carriage assembly 34. The barrel assembly 38 is connected to the stop platen 16 of the clamp unit 12 through the use of a carriage cylinder 30 which acts to force the carriage along the barrel assembly 38 so that the melt is in operation. It is shown that the mechanical nozzle 44 of the barrel assembly 38 remains engaged within the sprue bushing 55 of the injection mold during injection into the mold.

The barrel assembly 38 is shown in more detail to include an elongated cylindrical barrel 40 having an axial cylindrical bore 48A arranged therethrough, the bore within which for processing and transport of the metal feedstock. And arranged to cooperate with screw 56 as a means of accumulating and continuously sending a melt of molding material during injection. The screw 56 comprises a helical flight 58 arranged around an elongated cylindrical body 59, the rear of the screw (not shown) being configured to engage the drive assembly 36 and the front of the screw. The part is configured such that the actuating portion receives the non-return valve 60 according to the invention arranged in front of the front mating surface 57 of the screw 56. The barrel assembly 38 also includes a barrel head 42 positioned midway between the machine nozzle 44 and the front end of the barrel 40. The barrel head 42 includes a complementary melt passageway 48C arranged through the machine nozzle 44 and a throughly arranged melt passageway 48B connecting the barrel bore 48A. The melt passage 48B arranged through the barrel head 42 includes an inward taper to change the diameter of the melt passage to a much narrower melt passage 48C of the machine nozzle 44. The center bore 48A of the barrel 40 is also shown to include a liner 46 to protect the barrel base material from the corrosiveness of the hot metal melt. Other portions of the barrel assembly 38 that are in contact with the melt of molding material may also include similar protective linings or coatings. The barrel 40 is further configured to connect with a source of pulverized metal feedstock through a feed throat not shown, which is located through an upper rear portion of the barrel not shown. The feed neck guides the feedstock into the bore 48A of the barrel 40, which is formed by controlled operation and mechanical actuation by the action of the screw 56 in cooperation with the barrel bore 48A. The material is then treated. Heat is provided by a series of heaters 50 arranged along a substantial portion of the length of the barrel assembly 38, all of which are not shown.

The clamp unit 12 includes a clamp base 18 having a stationary platen 16 securely held at its end, a clamp block 22 slidably connected to an opposite end of the clamp base 18, and a stationary platen. It is shown to include a moving platen 20 arranged to move between them on a set of tie bars 32 connecting 16 and clamp block 22 to each other. As is generally known, the clamp unit 12 is not shown to strike the moving platen 20 against the stop platen to open and close the injection mold halves 23, 25 arranged therebetween. It further comprises means. Clamping means, not shown, are also provided between the clamp block and the moving platen for the provision of the clamping force between the mold halves 23, 25 during the injection of the melt of the molding material. The hot half 25 of the injection mold is shown mounted on the face of the stationary platen 16 and the complementary cold half 23 of the mold is mounted on the opposite face of the moving platen 20.

More specifically, the injection mold comprises at least one molding cavity, not shown, formed in a closed cooperative manner between complementary molding inserts shared between the mold halves 23, 25. More specifically, the mold cold half 23 includes a core plate assembly 24 having at least one core forming insert, not shown, arranged therein. The mold hot half 25 includes a cavity plate assembly 27 having at least one complementary co-molded insert mounted on one side of the runner system 26 and arranged therein. The runner system 26 provides a means for connecting the melt passage 48C of the machine nozzle 44 with at least one forming cavity for its filling. As is generally known, runner system 26 may be an offset or multi-drop hot runner, cold runner, cold sprue or any other generally known melt dispensing means. In operation, the core and the co-molded insert cooperate to form at least one mold cavity for receiving and molding a melt of molding material received from the runner system 26 in the mold closing and clamping positions.

The molding process is usually

Iii) establishing a flow of metal feedstock into the rear end of the barrel 40;

Ii) a. Feedstock / through the non-return valve 60 along the length of the barrel 40 through the cooperation of the axial bore 48A and the screw flight 58 and into the accumulation zone defined in front of the non-return valve 60. Actuation (ie, rotation and deflation) of the screw 56 which functions to move the melt, and b. Working (ie, shearing) and heating the metal feedstock with a thixotropic melt of molding material by heating the feedstock material while moving along a substantial portion of the barrel assembly 38;

Iii) closing and clamping the injection mold halves 23, 25;

Iii) injecting the accumulated melt into the injection mold through the machine nozzle 44 by forward movement of the screw 56,

Iii) selectively filling any residual voids in the molding cavity through application of consistent injection pressure (ie, packing),

Iii) opening the injection mold when the molded part solidifies through cooling of the injection mold;

Iii) removal of the molded part from the injection mold,

Iii) optional control of the injection mold (e.g. application of a mold separator) for the next molding cycle.

The step for preparing a volume of melt for the next injection (i.e., step iii) and ii)) is generally known as "recovery" and is the step of filling and packing at least one mold cavity (i.e. Steps iii) and iii)) are generally known as "injection".

The aforementioned non-return valve 60 allows forward movement of the melt 40 from the front of the barrel 40 to the accumulation zone but prevents its backflow during injection of the melt. The proper function of the non-return valve 60 depends on the pressure difference between the melts on each side thereof (i.e. high behind the valve during recovery and high forward during injection). The construction and operation of a typical non-return valve for use in metal injection molding is described in US Pat. No. 5,680,894.

An example of a typical non-return valve 60 for use in the barrel assembly 38 of an injection molding machine is shown with reference to FIGS. 3A, 3B and 3C. More specifically, the non-return valve 60 includes a tip member 62 configured to be retained in the front portion of the screw 56 and a ring member configured to cooperate with the tip member 62 between the defined recovery and ejection positions along it. 64 and a flange member 66 arranged behind the ring member 64 on the tip member 62 to limit the backward movement of the ring member 64 and to seal with the ring member 64 in the ejected position. It is further configured.

Tip member 62 includes a cylindrical body 63 with tip flange 81 and retention flange 73 arranged thereon on the front and middle sections, respectively. Along the length of the tip member 62, arranged rearward to front, the screw engagement portion 68, the alignment portion 70, the seat portion 72, the annular flow portion 74, the front retaining portion 76, There is a functional portion that includes a tip peripheral portion 80, a tip taper portion 82, and a tip plane portion 86.

The screw engagement 68 is configured to hold the tip member 62 at the front of the screw 56 and is provided by forming a helical thread along it as part of the spiralized engagement.

Alignment 70 is configured to axially align tip member 62 with the longitudinal axis of screw 56 and thereby cooperate with a complementary mating portion 70 ′ formed in the front portion of screw 56. Provided by a cylindrical mating surface. Alignment 70 is also used to similarly align flange member 66 between front mating surface 57 of seat 56 and seat portion 72.

The seat portion 72 includes an undercut formed at the front of the alignment portion 70 and at the back of the seat flange 73.

The annular flow portion 74 includes rear and front cylindrical flow segments joined by forwardly inclined segments, the rear and inclined segments being provided on the outer periphery and front surface of the seat flange 73, respectively. The annular flow portion 74 is in use with a complementary annular flow portion 74 ′ defined along the interior of the ring member 64 to define an annular melt passageway 77 therebetween when the ring member is in the recovery position. Cooperate.

The tip flange 81, arranged along the remaining length of the tip member 62, has a front retaining portion 76, a tip circumference portion 80, a tip taper portion 76, and a tip plane portion 86 on its back, outer surface. , Front inclined surface and front surface respectively. Four radially spaced axial melt discharge grooves 84 are also arranged at equal intervals through the outer and inclined surfaces of the tip flange 81 and around the tip flange 81 extending between the back and front surfaces and , Having a longitudinal axis parallel to that of the tip member 62, and having a depth approximately equal to the front segment of the annular flow portion 74. The melt discharge groove 84 provides a passage for discharge of the melt from the annular melt passage 77 to the accumulation zone in front of the barrel bore 48A.

The front retainer 76 cooperates with the complementary front retainer 76 ′ defined on the ring member 64 to limit the forward movement of the ring member 64 in use. The front retainer 76 ′ of the ring member 64 is complementary to the retainer 76 of the tip member 62 under the influence of the melt pressure generated behind the non-return valve 60 by the rotation of the screw 56. Ring member 64 is in its recovery position and the annular melt passageway 77 is open when pressed to engage. The surface of the front retainers 76, 76 ′ is shown to be provided by a resilient hard surface material 78 to avoid its deformation from the periodic impact of the front retainers 76, 76 ′.

The diameter of the tip circumference 80 is configured to cooperate with the barrel bore 48A to assist in the alignment of the barrel bore 48A and the tip member 62, which alignment is otherwise aligned with the screw 56 generally. It is provided by a close fit between the screw flights 58 inside the barrel bore 48A, which is kept as far as possible (because it tilts under its own weight, the screws 56 are not in precise alignment) For practical reasons that there is typically a sufficient gap between and the barrel bore 48A). During injection, the tapered portion 82 and the planar portion 86 both function to pressurize the melt from the front as the non-return valve 60 is pushed forward along the barrel bore 48A.

The ring member 64 includes an annular body 94. The outer circumferential surface 96 of the annular body 94 is fitted closely within the barrel bore 48A and cooperates with it to guide the ring member 64 as a force is applied to move along it during recovery and injection. It is composed. The ring member 64 and the tip member 62 are generally aligned with each other and centered with the barrel bore 48A as characterized above, but there is no direct means provided for alignment between them.

The ring member 64 also includes a piston ring seat 95 formed as a peripheral groove through the outer circumferential surface 96 between the ends of the ring member 64. The piston ring seat 95 is configured to receive a piston ring 98 and sub-rings 100 thereunder, the outer surface 99 of the piston ring 98 being melted therebetween during injection. A seal is provided between the ring member 64 and the barrel bore 48A to prevent bypass. A plurality of pressure ports 97 are provided which connect the piston ring seat 95 and the annular melt passageway 77 and pressurize the region behind the subring 100 with the melt during injection. The pressurization of the zone behind the sub ring 100 causes the sub ring 100 and the piston ring 98 to expand radially, between the surface of the barrel bore 48A and the outer surface 99 of the piston ring 98. To give a sealing force. The sub ring 100 acts to seal the split provided in the piston ring to limit the escape of the pressurized melt. The annular flow portion 74 ′ is configured to follow the profile of the complementary annular flow portion 74 of the tip member 62 in an arrangement spaced therebetween to form an annular melt passageway 77 therebetween.

The rear retaining seal 90 'is constructed along a tapered surface inwardly of the annular body 94. The rear retaining seal 90 'functions to cooperate with the complementary rear retaining seal 90 provided on the front face of the flange member 66, limiting the rearward movement of the ring member 64 and Provided therein a face seal 91 intended to prevent backflow of the melt during injection when 64 is pressed into the injection position.

Likewise, the front retainer 76 ′ whose function has been described above is provided on the planar front face of the annular body 94. Anterior retainer 76 ′ is shown to be provided on a hard side material 78.

The flange member 66 includes an annular body 92 having a spacing flange portion 93 protruding from the base of the tapered front face. The inner circumferential surface extends across the annular body 92 and provides a complementary alignment 70 'configured to cooperate with the alignment 70 of the tip member 62, as described above. The flange member 66 on the top. The rear plane of the annular body 92 is coupled with the screw mating surface 57 when positioning the complementary seat portion 72 'provided on the front face of the gap flange 93 into the seat portion 72 on the tip member. A complementary mating surface 57 ′ configured to cooperate is provided to firmly position the flange member 66 therebetween. The front face of the annular body 92 provides the retention seal 90 described above configured to cooperate with the complementary retention seal 90 'of the ring member 64 in the ejected position, so that the ring member 64 Limits backward movement and seals in between (ie closes the melt passage 77). The retention seal 90 'is shown to be provided on a hard surface material 78. The diameter of the flange member 66 is significantly narrower than the barrel bore 48A such that the annular gap formed therebetween provides a melt passageway for the forward passage of the melt during recovery.

Another example of a generally known non-return valve 60 for use in the barrel assembly 38 of a metal injection molding machine is shown with reference to FIGS. 4A, 4B, 4C and 4D. The structure and operation of the non-return valve 60 are generally the same as those previously described and shown in Figures 3A, 3B and 3C. Accordingly, only differences in structure and operation between the embodiments are examined, and similar reference numerals are given to configurations common to both embodiments. A notable difference is that the front retaining portion 76 ′ on the ring member 64 is a plurality of conformal spaced standoffs 102, with the ring member 64 having two piston rings 98 around its outer surface. Includes installation and sub-ring 100 is not used in between, and is the general configuration of tip flange 81. As can be seen in FIG. 3A, the tip flange 84 lacks radially spaced axial melt discharge grooves 84 because the tip periphery 80 is configured to be much narrower than the barrel bore 48A. The gap between provides a discharge passage. Tip circumference 81 also includes a hexagonal arrangement of tooling flats 104 to assist in the installation and removal of tip member 62 in screw 56. Finally, the tip member 81 includes a ball nose portion 87 instead of the planar portion 86, which is a change that is not critical to the pressurization of the melt.

Proper operation of these types of non-return valves 60 is, during injection, the intimate face provided between the complementary rear retaining seals 90 ′, 90 arranged on the ring member 64 and the flange member 66, respectively. It depends on the seal 91. Without the intimate face seal 91, severe leakage can occur due to a sudden loss of pressure drop across the ring member.

Although not well understood, failure to achieve and / or maintain an intimate face seal 91 for the duration of the injection step is believed to be caused by factors including melt non-uniformity and injection dynamics.

More specifically, the non-uniformity of the melt of the molding material (i.e., containing unmelted and irregularly sized feedstock particles) will allow the solid feedstock to be trapped between the retention seals 90, 90 '. Can be.

In addition, the mechanics inside the barrel assembly 38, in particular during injection, are particularly useful in order to avoid unreliable valve closure during the transition between injection and packing phases where the non-return valve undergoes almost instantaneous deceleration (ie face seal 91). Achieve and maintain imparting extreme and widely varying forces on the parts of the non-return valve 60 to the extent that it is often necessary to tolerate undesirable in the injection profile (ie the speed and acceleration of the screw 56). The ultimate kinetics is that at least one molding cavity with an extremely small amount of injection time (i.e. 30 to 50 milliseconds) is available without compromising filling problems due to melt solidification and due to the properties of the melt (ie low viscosity and compressibility). The time required to fully fill wealth). As a result, there is an extremely steep screw 56 acceleration and high injection speed (typically more than 6 meters per second) and the lack of melt compressibility after filling at least one molding cavity effectively stops the screw 56 instantaneously. Loss of intimate contact most often occurs at the initial closing shock (ie, transition from recovery to injection) and at the end of injection due to the sudden deceleration of the screw.

Unfortunately, practical experiments also show that the integrity of the elastic seals 90, 90 'and thus the ability to achieve an intimate face seal 91 degrades at an unacceptably high rate under normal operating conditions. Indicates. Thus, frequent compensation adjustments to the molding process are required to compensate for the increase in backflow across the non-return valve 60 (eg, increasing the volume of melt in the accumulation zone, reducing the injection speed, etc.). Rapid deterioration of the retention seals 90, 90 'is not well understood, but the contributing factors are off-center loading, high impact forces and enveloping solids (e.g., not melted) caused by poor alignment. Unrestricted feedstock, solid carbon particles remaining from feedstock pulverization, introduced with feedstock, etc.). Moreover, it has been found that the higher the proportion of solids in the molding material, the faster the retaining seals 90, 90 'deteriorate. To further aggravate the problem, high melt temperatures (typically above 600 ° C.) can slowly unwind the substrate material of the valve component, reducing the elasticity of the retaining sealing surfaces 90, 91 ′.

Deterioration of the retention seals 90, 90 ′ generally requires repair or replacement of the non-return valve 60 in as little as a molding cycle (ie, weeks of service), such as 10 to 60,000, which causes injection And barrel assemblies 29 and 38 must be dismantled and are so time consuming and complex that all routine problems are caused by the solidified molding material remaining therein. These service demands result in high costs of low productivity (i.e. low system availability) and require highly skilled technical labor.

Thus, there is a need for improved non-return valves for use in molding systems that provide more durable and reliable valve closure. More specifically, there is a need for non-return valves for use in injection molding machines for molding metal alloys with improved means for sealing against backflow of molding materials during injection.

The non-return valve of the invention maintains its function despite any temporary movement between the ring and the tip member, which substantially limits the backflow of the melt through the melt passageway of the non-return valve at the injection position. Advantageously including "spigot-seal". The spigot seal is provided between complementary male and female spigot portions that are overlapping, closely spaced and parallel to each other that are constructed between any combination of the ring member, tip member, flange member or end of the screw. The spigot portion is also characterized in that its surface normal is substantially perpendicular to the longitudinal axis of the non-return valve. The spigot seal may be used alone or in combination with a face-seal (eg, between a ring and a flange member). When used in combination with a face seal, the spigot seal is intended to mitigate any pressure loss that may be due to the temporary loss of an intimate face seal.

Another advantage provided by the spigot seal is its elasticity. More specifically, the spigot seal functions by limiting melt flow between closely spaced spigot portions and thus is less susceptible to small misalignment between the ring and tip member and deterioration of the surface quality of the spigot portion.

The non-return valve of the present invention advantageously comprises means for aligning the tip and ring members with each other. Preferably, the means for aligning is axially oriented so that the complementary seal and / or rear retainer provided thereon in use is divided between the tip and ring member and oriented with each other as they engage with each other in a closing impact. Provided as complementary parts that cooperate to align. Thus, more consistent and uniform loading of complementary seals and / or rear retainers will help minimize degradation due to high impact forces (ie avoiding off-center loading). Preferably, the means for aligning the tip and ring members with each other is further configured to guide the ring member to be continuously aligned with the tip member between the ejection and recovery positions.

Means for aligning the tip and ring members with each other may also advantageously be used in combination with a spigot seal. Thus, proper alignment between closely spaced spigot portions is ensured. Moreover, complementary alignment and spigot portions may also be advantageously configured, respectively, across a common surface on the ring and tip member.

The tip member, the ring member, and the means for aligning the tip and ring member with each other are also faced by acting against the dynamics that tend to displace the ring member momentarily as the screw suddenly slows down at the end of the injection and at initial impact. It may be advantageously configured such that the weight component of the screw 56 is oriented substantially perpendicular across the complementary alignment so that a suitable frictional force is generated therebetween to help maintain the seal 91. Friction also reduces the loss of any instantaneous contact between the face seal 91 seals at the beginning of injection by preventing the unconstrained ring member from "taking-off" due to the initial closing impact. You can also

According to a first aspect of the invention, there is provided a non-return valve configured for use in a flow channel of a forming system. The non-return valve includes a tip member and a ring member arranged around the middle portion of the tip member in use. The tip and ring members are configured to support relative longitudinal reciprocating motion between the open and closed positions with respect to each other in use. The non-return valve further includes a rear retainer comprising complementary retainers arranged on the tip and ring member to limit backward movement between the ring and the tip member to a closed position in use. Similarly, the non-return valve further includes a front retainer comprising complementary retainers arranged on the tip and ring member to limit forward movement of the ring and tip member to the open position in use. The non-return valve also includes a plurality of melt flows configured along at least two of the ring member, the tip member, and any retaining portion. The melt flow is configured to cooperate to provide a melt flow passage therebetween when the ring and tip members are arranged in the open position. The non-return valve also includes at least a pair of complementary spigots configured on the melt flow portions that cooperate in a substantially closely spaced, overlapping and parallel arrangement when the ring and tip members are in the closed position. In use, the complementary spigot provides a spigot seal that substantially limits the backflow of the melt therebetween when the ring and tip member are in the closed position.

Exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a side view of a conventional injection molding system.

2 is a partial cross sectional view through a portion of an injection molding machine, including a barrel assembly 38 coupled within a hot half 25 of an injection mold mounted on a stationary platen 16.

3A, 3B and 3C are perspective, front and sectional views, respectively, of a non-return valve according to the prior art, and the cross-sectional view is taken along cut line A-A of FIG. 3B with the non-return valve configured for injection.

4A, 4B, 4C, and 4D are perspective, front, and cross-sectional views, respectively, of a non-return valve in accordance with the prior art, with a cross-sectional view of the non-return valve configured for injection and recovery, respectively, in FIGS. 4C and 4D, respectively. 4B is taken along the cut line AA of FIG. 4B.

5A, 5B, 5C, and 5D are perspective, front and sectional views, respectively, of a non-return valve according to a first embodiment of the present invention, the cross-sectional views of which the non-return valve is ejected and recovered in FIGS. 5C and 5D. 5B is a view taken along the cutting line AA of FIG.

6A, 6B, 6C, and 6D are perspective, front, and cross-sectional views, respectively, of a non-return valve in accordance with a presently preferred embodiment of the present invention, the cross-sectional views of the non-return valve being shown in FIGS. 6C and 6D for injection and recovery. 6B is a view taken along the cutting line AA of FIG. 6B.

7A, 7B, 7C and 7D are perspective, front and sectional views, respectively, of a non-return valve in accordance with another embodiment of the present invention, the cross-sectional views of which the non-return valve is for injection and recovery in FIGS. 7C and 7D. Fig. 7B is taken along the cutting line AA of Fig. 7B, which is a configured state.

8A, 8B, 8C, and 8D are perspective, front, and cross-sectional views, respectively, of a non-return valve in accordance with another embodiment of the present invention, the cross-sectional views of the non-return valve being shown in FIGS. 8C and 8D for injection and recovery. 8B is a view taken along the cutting line AA of FIG. 8B.

9A, 9B, 9C, and 9D are perspective, front, and cross-sectional views, respectively, of a non-return valve in accordance with another embodiment of the present invention, the cross-sectional views of which the non-return valve is for injection and recovery in FIGS. 9C and 9D. Fig. 9B is taken along cut line AA in Fig. 9B, which is in a state of being configured.

10A, 10B, 10C, and 10D are perspective, front, and cross-sectional views, respectively, of a non-return valve in accordance with another embodiment of the present invention, the cross-sectional views of which the non-return valve is for injection and recovery in FIGS. 10C and 10D. Fig. 10B is taken along cut line AA in Fig. 10B.

11A, 11B, 11C, and 11D are perspective, front, and cross-sectional views, respectively, of a non-return valve in accordance with another embodiment of the present invention, the cross-sectional views of which the non-return valve is for injection and recovery in FIGS. 11C and 11D. Fig. 11 is a view taken along the cutting line AA of Fig. 11B, which is a configured state.

12A, 12B, 12C, and 12D are perspective, front, and cross-sectional views, respectively, of a non-return valve in accordance with another embodiment of the present invention, the cross-sectional views of which the non-return valve is for injection and recovery in FIGS. 12C and 12D. Fig. 12B is taken along cut line AA in Fig. 12B, which is in a state in which each is configured.

13A, 13B, 13C, and 13D are perspective, front, and cross-sectional views, respectively, of a non-return valve in accordance with another embodiment of the present invention, the cross-sectional views of which the non-return valve is for injection and recovery in FIGS. 13C and 13D. Fig. 13B is taken along cut line AA in Fig. 13B, which is in the configured state.

14A, 14B, 14C, and 14D are perspective, front, and cross-sectional views, respectively, of a non-return valve in accordance with another embodiment of the present invention, the cross-sectional views of which the non-return valve is for injection and recovery in FIGS. 14C and 14D. Fig. 14B is taken along cut line AA in Fig. 14B, which is in a configured state.

15A, 15B, 15C, and 15D are perspective, front, and cross-sectional views, respectively, of a non-return valve in accordance with another embodiment of the present invention, the cross-sectional views of which the non-return valve is for injection and recovery in FIGS. 15C and 15D. Fig. 15B is taken along the cut line AA of Fig. 15B, which is a configured state.

1, 5A, 5B, 5C and 5D, there is shown a non-return valve according to a first embodiment of the present invention configured for a barrel assembly 38 of an injection molding machine 10. As shown in FIG. The non-return valve 160 is a tip member 162 configured to be retained in the front portion of the screw 56, the tip member 162 slidably arranged on the tip member 162 and thus defined between the recovery and ejection positions. A ring member 164 configured to cooperate with a flange member 166 arranged behind the ring member 164 at the rear portion of the tip member 162.

Tip member 162 includes a cylindrical body 63 having a conical tip flange 81 and a cylindrical spigot flange 173 respectively arranged around the front middle section. Along the length of the tip member 162, the screw coupling portion 68, the alignment portion 70, the seat portion 72, the outer guide spigot flow portion 110, the routing portion 120, which are arranged from the rear to the front. ), A functional portion comprising a front retaining portion 76, a tip peripheral portion 80, a tip taper portion 82 and a ball-nose portion 87 is located.

The screw coupling portion 68 is provided by forming a spiral helix along with a portion of the helixed coupling configured to hold the tip member 162 at the front of the screw 56.

Alignment 70 is configured to axially align tip member 162 with the longitudinal axis of screw 56 and thereby cooperate with a complementary mating portion 70 ′ formed in the front portion of screw 56. According to the cylindrical mating surface. Alignment 70 is also used to similarly align flange member 166 between front mating surface 57 of seat 56 and seat portion 72. The seat portion 72 includes an undercut formed in the back of the spigot flange 173 and in front of the alignment portion 70.

Outer guide spigot flow 110 is configured along the outer circumferential surface of spigot flange 173. The outer guide spigot flow 110 is configured to cooperate with the complementary inner guide spigot flow 112 on the ring member 164 to be continuously aligned with the tip member 162 between the ejection and recovery positions. Guide 164 and provide a spigot seal therebetween as described above when the ring member 164 is in the ejected position. The inner guide spigot flow 112, which will be described later, is configured along the inner circumferential surface of the ring member 164. The outer guiding spigot flow portion 110 also has a melt branch passageway 177B with the guide spigot flow portion of the respective delivery portion 118 and the tip member 162 when the ring member 164 is in the recovery position. It is configured to cooperate with a number of delivery portions 118 provided around the inner back portion of the ring member 164 described below to be provided between 110.

Routing portion 120 is provided between the front face of spigot flange 173 and the rear face of tip flap 81. The routing section 120 defines a routing melt passageway 177C between a plurality of radially spaced axial melt discharge grooves 84 arranged along the tip flange 81 and an overlap of each delivery section 118. It is configured to cooperate with the spigot flow sub-114 of the ring member 164 when the ring member 164 is in the recovery position to provide.

The tip flange 81, arranged along the remaining length of the tip member 162, has a front retaining portion 76, a tip peripheral portion 80, and a tip taper portion 82 on its back, outer surface, front inclined surface and front surface, respectively. And tip ball-nose portion 87. Five radially spaced axial melt discharge grooves 84 are arranged equidistally spaced about the tip flange 81 and along the tip member 162 between the back and inclined surfaces of the tip flange 81. It extends substantially parallel to the longitudinal axis of 62 and through the outer and inclined surfaces of the tip flange 81 to the approximate depth of the routing portion 120.

The front retainer 76 cooperates with the complementary front retainer 76 ′ defined on the front face of the ring member 164 to limit the forward movement of the ring member 164 in use. The front retainer 76 ′ of the ring member 164 is complementary to the retainer 76 of the tip member 162 under the influence of the melt pressure generated behind the non-return valve 160 by the rotation of the screw 56. When pressed to engage with the ring member 164 is in its recovery position and the melt passageway 177 (ie 177A, 177B, 177C) is open.

The diameter of the tip peripheral portion 80 is configured to cooperate with the barrel bore 48A to help align the barrel bore 48A and the tip member 162. During injection, both the tapered portion 82 and the ball-nose portion 87 function to pressurize the melt at its front as the non-return valve 160 is pushed forward along the barrel bore 48A.

Ring member 164 includes an annular body 94. The outer circumferential surface 96 of the annular body 94 is configured to cooperate with the guiding ring member 164 as it fits tightly inside the barrel bore 48A and is pressed to move along with it during recovery and injection. .

The ring member 164 also includes a piston ring seat 95 formed as a peripheral groove through the outer peripheral surface 96 between the ends of the ring member 164. The piston ring seat 95 is configured to receive the piston ring 98 (without the sub ring 100), the outer surface 99 of the piston ring 98 being between the ring member 164 and the barrel bore 48A. To provide a seal to prevent the bypass of the melt between injections. A plurality of pressure ports 97 are provided extending between the front retainer 76 ′ and the piston ring seat 95 for the purpose of forcing the zone behind the piston ring 98 with melt during injection as described above. .

The front retaining portion 76 ′ previously introduced provides a function on the front face of the plane of the annular body 94 and limits the forward movement of the ring member 164 along the tip member 162 to the recovery position. do.

The rear retention seal 90 'is configured along the rearward inwardly tapered face of the annular body 94. The rear retaining seal 90 'cooperates with the complementary rear retaining seal 90 provided on the front face of the flange member 166 to limit the rearward movement of the ring member 164 along the tip member 162. To arrange the ring member 164 at the ejection position and to provide a face seal 91 therebetween. The rear retaining seal 90 is shown as provided on a rigid cotton material 78 to improve its resilience.

The inner circumferential surface of the annular body 94 provides the previously introduced guide spigot flow 112. Guided spigot flow 112 includes two functional sub-portions comprising a spigot flow sub-114 and a plurality of axial guide sub-116s.

The spigot flow sub-114 is provided as a narrow cylindrical band extending along the front of the inner circumferential surface of the annular body 94. The spigot flow sub-114 is configured to cooperate with the complementary front of the outer guided spigot flow 110 to establish the spigot seal 122 in the ejected position. As shown in Fig. 5C, when the ring member 164 is pressed into the ejection position, the spigot flow sub-114 (female) is formed with the front portion of the outer guide spigot flow 110 (male). Located in closely spaced, overlapping and parallel arrangements, the tight spaces between these complementary spigot portions 114, 110 (i.e., the very small differences in diameter) prevent the reverse flow of the melt passing therethrough. Effectively restricts the function.

Axial guide sub-section 116 is configured along the inner peripheral surface of four narrow, arcuate and longitudinally extending members. The longitudinally extending member is the remainder of the formation of four identical, conformally spaced and arcuate grooves formed through the inner circumferential surface of the annular body 94 and from the rear edge of the spigot flow sub-114 It extends through the rear face of the annular body 94. The groove provides the delivery section 118 previously introduced. The axial guide sub-section 116 is complementary to the outer guide such that the ring and tip member 164 maintains mutual axial alignment as the ring member 164 moves relative to the tip member 162 between the ejection and recovery positions. Configured to cooperate with spigot flow 110. More specifically, the axial guide subsection 116 is configured to fit around the complementary outer guide spigot flow 110 in a closely spaced (ie, very small difference in diameter) arrangement. This slide and alignment fit will be referred to as a "running-fit" 123. The provision of the running-fit 123 between the ring and tip members 164, 162 ensures that the spigot flow sub-114 is aligned with the closely spaced complementary front of the guide spigot flow 110. And greatly to ensure that they can be combined. Preferably, the screw 56 and the non-return valve 160 have a tip component and an axial guide sub-section 116 of the ring member 164 such that the component of the weight of the screw 56 is a suitable friction force is generated therebetween. It is configured in barrel bore 48A to be oriented substantially at right angles between outer guide spigot flow 110 of 162. The frictional force between the complementary guides 110, 116 is provided between the piston ring outer surface 99 and the barrel bore 48A, as the screw suddenly decelerates during the initial impact and at the end of the injection. By acting on dynamics that are likely to move the ring member momentarily, it helps to maintain the face seal 91 between the complementary retention seals 90 and 90 '.

The flange member 166 includes an annular body 92 having a spacing flange 93 that projects from the base of its tapered front face. The inner peripheral surface is complementary configured to extend across the annular body 92 and cooperate with the alignment portion 70 of the tip member 162 to align the flange member 166 on the tip member 162 as described above. An alignment portion 70 'is provided. The rear plane of the annular body 92 cooperates with the screw mating surface 57 when positioning the complementary seat portion 72 'provided on the front face of the spacing flange 93 into the seat portion 72 on the tip member. A complementary mating surface 57 'configured to securely position the flange member 166 therebetween. The front face of the annular body 92 restricts the backward movement of the ring member 64 and forms a face seal 91 therebetween (ie, closes the melt passageway 177) in the ring at the injection position. Provided above is a retention seal 90 ', configured to cooperate with a complementary retention seal 90' of member 64. Complementary retention seals 90, 90 ′ also include an annular inlet passage (a large gap therebetween interconnecting the portion of barrel bore 48A behind non-return valve 160 and the melt branch passage 177B). It also cooperates when the ring member 164 is arranged in a recovery position providing 177A). Preferably, the retention seal 90 'is provided on a hard surface material 78. The diameter of the flange member 166 is considerably narrower than the barrel bore 48A such that the annular gap formed therebetween provides the melt passageway for forward passage of the melt during recovery.

6A, 6B, 6C and 6D, a non-return valve 260 according to a presently preferred embodiment of the present invention for use in the barrel assembly 38 of the injection molding machine 10 is shown. Non-return valve 260 is very similar to that previously described and shown with reference to FIGS. 5A, 5B, 5C, and 5D. Accordingly, only differences in structure and operation between the embodiments will be considered and configurations common to both embodiments are provided with similar reference numerals. As before, the non-return valve 260 includes a tip member 262, a ring member 164 ′ and a flange member 166.

The non-return valve 260 is an example of the reconstruction of the complementary spigot and guide where the position of the spigot seal 122 is moved closer to the face seal 91. Thus, the ring and tip members 164 ', 262 include complementary inner and outer guide spigot flows 112', 210, respectively.

More specifically, the inner guided spigot flow 112 'is constructed across the inner circumferential surface of the annular body 94, and the spigot flow sub-114' and a plurality of axial guided sub-sections 116 '. Includes two functional subparts, The relative longitudinal range of the functional subsections 114 ′ and 116 ′ has been modified to accommodate backward movement at the location of the spigot seal 122. More specifically, the longitudinal range of the guide spigot flow sub-114 'is much longer while the range of the axial guide sub-section 116' is correspondingly shorter. Thus, the spigot portion was moved to the rear of the spigot flow sub-114 '. As a result of the change in the configuration of the inner guide spigot flow portion 112 ', the longitudinal range of the delivery portion 118', which is defined by the groove between the axial guide sub-sections 116 ', has also been correspondingly shortened.

Outer guide spigot flow 210 is configured across the outer circumferential surface of cylindrical spigot flange 273 provided around the middle section of tip member 262. As long as the non-return valve 260 operates without changing the length of the tip member 262 and the stroke length (measured between the ejection and recovery positions) of the ring member 164 'in the same manner as described above. It is necessary to change the longitudinal range of the spigot flange 273 and consequently the range of the front guide spigot flow portion 210 and the routing portion 220 of its front in proportion to the change of the length of 118 '. . Thus, the spigot flange 273 is narrower considering the short transmission 118 'described above.

It should also be appreciated that it was also possible to move the inlet for the piston ring pressure port 97 just below the piston ring seat 95 of the spigot flow sub-114 'because of the increased length of the routing 220.

Other differences in the configuration of the tip member 262 are not particularly relevant to the present invention and merely illustrate other possible variations. These include cutting the tip portion 81 to include the tip plane portion 86 instead of the ball-nose 87, providing only four melt discharge grooves 84 instead of five, and the periphery portion 80 having a tip member ( Not configured to cooperate with barrel bore 48A to provide any additional guidance for 262 (ie, running-fit between ring and tip members 164 ′, 262). Need not be provided).

7A, 7B, 7C and 7D, a non-return valve 360 in accordance with another embodiment of the present invention, configured for the barrel assembly 38 of the injection molding machine 10, is shown. Non-return valve 360 is very similar to that previously described and shown with reference to FIGS. 5A, 5B, 5C, and 5D. Accordingly, only differences in structure and operation between the embodiments are examined and configurations common to both embodiments have been given similar reference numerals. As before, the non-return valve 360 includes a tip member 362, a ring member 264 and a flange member 266.

The non-return valve 360 is another of the reconstruction of the complementary spigot and guide where an additional spigot seal 122 is provided between the ring and tip members 264, 362 directly adjacent the face seal 91. Yes. Thus, the ring member 264 includes an inner guided spigot flow 212 and the tip member 362 includes a complementary rear outer spigot flow 310 and a front outer guided spigot flow 311. do.

More specifically, the inner guided spigot flows 212 are both constructed across the inner circumferential surface of the annular body 94. Inner guide spigot flow portion 212 includes three functions including a front spigot flow sub portion 215, a rear spigot flow sub portion 214, and four axial guide sub portions 216 configured therebetween. Sub-section.

The rear and front spigot flow sub-sections 214, 215 are both provided in narrow cylindrical bands extending along the rear and front portions of the inner circumferential surface of the annular body 94, respectively. The front and rear spigot flow sub-parts 214, 215 are complementary to the posterior outer spigot flow 310 which is complementary to establish a spigot seal 122 therebetween when the ring member 264 is in the ejected position. And cooperate with the front outside guide spigot flow portion 311. Similarly, the rear and front spigot flow sub-sections 214, 215 provide tip members 362 to provide delivery and routing melt passageways 377B, 377D therebetween when the ring members 264 are in the recovery position, respectively. Configured to cooperate with each of the delivery unit 319 and the routing unit 320 provided therein. The configuration of the transfer unit 319 and the routing unit 320 will be described below.

Axial guide sub-section 216 is configured along the inner peripheral surface of four narrow, arcuate, and longitudinally extending members. The longitudinally extending members form four identical, conformally spaced, and arcuate grooves through the inner circumferential surface of the annular body 94 extending between the rear and front spigot flow sub-sections 214, 215. Is the rest. Each groove provides a delivery portion 218 configured to cooperate with the front outer guide spigot flow portion 311 when the ring member 164 is in the recovery position, thereby routing the melt transfer passage 377B to the melt. It defines a melt branch passage 377C that connects with the passage 377D. The axial guiding sub-section 116 runs to keep the ring and tip members 264, 362 in mutual axial alignment as the ring member 264 moves relative to the tip member 262 between the ejection and recovery positions. Configured to cooperate with a forward-outward guiding spigot flow 311 that is complementary with a running-fit.

The tip member 362 has a rear outer spigot flow portion 310, a transfer portion 319 and a front outer guide, in which the functional portion between the seat portion 72 and the routing portion 120 is arranged from the rear to the front. It is essentially configured like tip member 262 except that it includes spigot flow 311. The rear outer spigot flow 310 is provided on the outer surface of the cylindrical second spigot flange 374. The second spigot flange 374 is about the same width as the rear spigot flow sub-section 214. Moreover, the second spigot flange 374 is positioned along the tip member 362 so that the back side provides a portion of the seat portion 72 for the retention of the flange member 266, thereby rearward spigot flow portion 310 is located immediately adjacent the rear retaining seal 90 'of the flange member 266. The front outer guide spigot flow 311 is provided on the outer surface of the cylindrical first spigot flange 373. The first spigot flange 373 is positioned along the tip member 362 and the first spigot flange such that the front lateral spigot flow portion 311 is positioned directly below the complementary front spigot flow sub-section 215. The front face of 373 is located adjacent to the rear retaining portion 76 'of the ring member 264 when the ring member is in the ejected position. The transfer portion 319 is located between the front face of the second spigot flange 374 and the back face of the first spigot flange 373. The width of the first spigot flange 373 is shown approximately twice the width of the front spigot flow sub-section 215. As such, the first spigot flange 373 is wide enough to cooperate with the front spigot flow sub-section 215 to provide the spigot seal 122 when the ring member 264 is in the ejected position. Additionally, the first spigot flange 373 is narrow enough to allow the delivery 214 in the ring member 264 to spread out the front outer guide spigot flow 311 when the ring member 264 is in the recovery position. The end of delivery 218 overlaps both delivery 319 and routing 120 within tip member 362 to connect melt passageways 377B, 377C, and 377D.

Other differences in the configuration of the tip member 362 are not particularly relevant to the present invention and merely illustrate other possible variations. These include cutting the tip portion 81 to include the tip plane portion 86 instead of the ball nose 87, providing only four melt discharge grooves 84 instead of five, and the periphery portion 80 having a tip member 362. And not configured to cooperate with the barrel bore 48A to provide any additional guidance. Similarly, the flange member 266 differs only in that the gap flange 93 is omitted.

8A, 8B, 8C and 8D, there is shown a non-return valve 460 according to another embodiment of the present invention configured for the barrel assembly 38 of the injection molding machine 10. Non-return valve 460 is very similar to that previously described and shown with reference to FIGS. 7A, 7B, 7C, and 7D. Accordingly, only differences in structure and operation between the embodiments are examined and similar reference numerals have been given to configurations common to both embodiments. As before, the non-return valve 460 includes a tip member 462, a ring member 264, and a flange member 266.

Non-return valve 460 is another example of a reconstruction in which rear and front spigots and guides on tip member 462 are configured along a common spigot flange and additional guides are provided therebetween. Accordingly, the tip member 462 includes an outer guide spigot flow sub portion 409 defined along the outer circumferential surface of the spigot flange 473. Outer guide spigot flow 409 includes a rear outer spigot flow sub 410, a front outer guide spigot flow sub 411 and a plurality of axial guide subs 413 configured therebetween. It includes three functional subparts. The addition of the axial guide sub portion 413 complements the inner and outer guide spigot flows 211, which further aid in aligning the tip and ring members 462, 264 and provide additional friction therebetween. 409) to increase the amount of contact area between.

More specifically, the spigot flange 473 extends along the middle section of the tip member 462 at the same location and between the same outer restriction of the front rear and front spigot flanges 374, 373. The posterior outer spigot flow sub-part 410 and the posterior outer guiding spigot flow sub-part 411 are configured along the rear and front of the outer circumferential surface of the spigot flange 473. The axial guide sub portion 413 is defined along the outer surface of the six narrow, arcuate and longitudinally extending members. The longitudinally extending member is the remainder of the formation of six identical, conformally spaced, sharp grooves formed through the outer circumferential surface of the spigot flange 473, which is the rear outer spigot flow sub-part 410 and the rear outer Extends between the guiding spigot flow sub-parts 411. The groove provides a delivery portion 419 configured to cooperate with the complementary delivery portion 218 in the tip member 264 in the same manner as in the previous embodiment. The width of the posterior lateral spigot flow subsection 410 and the posterior lateral spigot flow subsection 411 are approximately equal to the complementary posterior and anterior spigot flow subsection 214, 215, respectively.

9A, 9B, 9C and 9D, a non-return valve 560 according to another embodiment of the present invention configured for the barrel assembly 38 of the injection molding machine 10 is shown. Non-return valve 560 is very similar to that previously described and shown with reference to FIGS. 8A, 8B, 8C, and 8D. Accordingly, only differences in structure and operation between the embodiments are examined and similar reference numerals have been given to configurations common to both embodiments. As before, the non-return valve 560 includes a tip member 462, a ring member 264, and a flange member 366.

Non-return valve 560 is a spigot seal without a face seal 91 provided between complementary rear retention seal 90 and retention portion 390 of ring member 264 and flange member 366, respectively. It is an example that portion 122 provides the entirety of the melt backflow restriction required during injection. Thus, four conformal spaced melt inlet grooves 367 are formed around the periphery of the flange member 366 extending through the outer periphery and between the rear and front surfaces. An inlet groove 367 extending through the retention surface 390 prevents the surface seal from being achieved with the rear retention seal surface 90 complementary on the ring member 264. The inlet groove 367 is also characterized in that it has a downward slope between the rear and front faces of the flange member 366, where the origin of the inlet groove 367 is the outer guide spigot oil on the tip member 462. The melt is directed to the melt inlet passage 477A when it intersects the front face of the flange member 366 immediately adjacent the eastern portion 409 and the ring member 264 is in the recovery position. Additionally, since the diameter of the flange member 366 is substantially the same as that of the outer surface 96 of the ring member 264, the outer diameter of the flange member 366 thus further centers the tip member 462. It is configured to cooperate with barrel bore 48A to assist.

10A, 10B, 10C, and 10D, a non-return valve 660 according to another embodiment of the present invention, configured for the barrel assembly 38 of the injection molding machine 10, is shown. Non-return valve 660 is very similar to that previously described and illustrated with reference to FIGS. 6A, 6B, 6C, and 6D. Accordingly, only differences in structure and operation between the embodiments are examined and similar reference numerals have been given to configurations common to both embodiments. As before, the non-return valve 660 includes a tip member 562, a ring member 364 and a flange member 266.

Non-return valve 660 is another example of the reconstruction of the complementary spigot and guide where the routing section 220 has been removed. Thus, the ring member 364 includes an inner guided spigot flow 312 and the tip member 562 includes a complementary rear outer spigot flow 51 and a front outer guided flow 511. .

More specifically, the inner guided spigot flow 312 is constructed across the inner circumferential surface of the annular body 94. Inner guide spigot flow 312 includes two functional sub-parts, including spigot flow sub-part 314 and four axial guide sub-parts 316.

The spigot flow sub-section 314 is provided as a narrow cylindrical band extending along the rear of the inner circumferential surface of the annular body 94. The spigot flow sub-314 is configured to cooperate with the complementary rear outer spigot flow 510 when the ring member 364 is in the ejected position to establish a spigot seal 122 therebetween. Likewise, spigot flow sub-314 is configured to cooperate with delivery 519 within tip member 562 when ring member 364 is in the recovery position to form a melt delivery passage 577B therebetween. do. The configuration of the delivery unit 519 will be described later.

Axial guide sub-section 316 is configured along the inner peripheral surface of four narrow, arcuate and longitudinally extending members. The longitudinally extending member from the formation of the arcuate groove, which diverges out four identical, conformally spaced, outwards (ie toward the front of the ring member 364) through the inner circumferential surface of the annular body 94. As a residue it extends from the front edge of the spigot flow sub-314 and through the front face of the annular body 94. Each groove is configured to cooperate with the front outer guide flow 551 when the ring member 364 is in the recovery position to provide a delivery 318 to define the melt branch passage 577C therebetween. Each melt branch passage 577C connects the melt transfer passage 577B with the melt discharge portal 577D. The melt discharge portals 577D are each delivered along the front face of the ring member 364, which is outside the outer surface of the tip flange 81 (ie, across the tooling flat 316 and the perimeter 80). Is formed between a portion of the portion 318. Axial guide sub-section 316 is configured to cooperate with forward outer guide flow 511 complementary to running pit 123 such that ring member 364 moves relative to tip member 562 between the ejection and recovery positions. Thereby keeping the ring and tip members 364, 562 in mutual axial alignment.

The tip member 562 has a rear outer spigot flow portion 510, a transmission portion 519, and a front outer side when the functional portion between the seat portion 72 and the front retaining portion 76 is arranged from rear to front. It is basically configured as before except that it includes the guide flow portion 511. The back outer spigot flow 510 is provided on the outer surface of the cylindrical spigot flange 574. Spigot flange 574 has a width approximately equal to spigot flow sub-314. Moreover, the spigot flange 574 is positioned along the tip member 562 such that its back side provides a portion of the seat portion 72 for the retention of the flange member 266, whereby the rear outer spigot flow portion ( 510 is located immediately adjacent the rear retaining seal 90 'of the flange member 266. The front outer guide flow 511 is provided on the outer surface of the cylindrical guide flange 573. Guide flange 573 extends along the tip between the rear face of tip flange 81 and delivery 519. The delivery 519 is provided between the front face of the spigot flange 574 and the back face of the guide flange 573. The width of the guide flange 573 is configured to hold the running pit 123 between the complementary guides on the ring and tip member 364, 562 between the ejection and recovery positions and the delivery unit 519 is configured to recover the ring member. When in position, its ends have a width sufficient to overlap with the spigot flow sub portion 314 on the ring member 364, thereby connecting the melt passages 577A, 577B, 577C to each other.

Other differences in the construction of the tip member 562 are not particularly relevant to the present invention and merely represent other possible variations. These include the removal of the melt discharge groove 84 by the narrow tip flange 81, the outer surface of the tip flange 81 of the ring member 364 to provide the melt discharge portal 577D as described above. And cooperate with the delivery unit 314 along the front face.

11A, 11B, 11C and 11D, a non-return valve 760 according to another embodiment of the present invention configured for the barrel assembly 38 of the injection molding machine 10 is shown. Non-return valve 760 is very similar to that previously described and shown with reference to FIGS. 10A, 10B, 10C, and 10D. Accordingly, only differences in structure and operation between the embodiments are examined and similar reference numerals have been given to configurations common to both embodiments. As before, the non-return valve 760 includes a tip member 662, a ring member 364 and a flange member 266.

Non-return valve 760 is another example of a reconstruction in which rear and front spigots and guides on tip member 662 are each configured along a common flange and additional guides are provided therebetween. Accordingly, tip member 662 includes an outer guide spigot flow 609 defined along the outer circumferential surface of spigot flange 673. The outer guiding spigot flow 609 comprises three rear lateral spigot flow sub-sections 610, a front outer guiding flow sub-section 611 and a plurality of axial guide sub-sections 613 configured therebetween. It includes a functional subpart. The addition of the axial guide sub portion 613 will further assist in aligning the tip and ring members 662, 364 and will provide complementary inner and outer guide spigot flow 312, which provides additional friction therebetween. Increase the amount of contact area between 609.

More specifically, the spigot flange 673 extends along the middle section of the tip member 662 at the same location and between the same outer restraints of the front rear and front flanges 574, 573. The rear outer spigot flow sub-section 610 and the front outer guide flow sub-section 611 are configured along the rear and front portions of the outer circumferential surface of the spigot flange 673. Axial guide sub-section 613 is defined along the outer surface of the six narrow, arcuate and longitudinally extending members. The longitudinally extending member is the remainder of the formation of six identical, conformally spaced, arcuate grooves formed through the outer circumferential surface of the spigot flange 673 and is anterior to the posterior outer spigot flow sub-section 610. It extends between the outer guide flow sub-parts 611. The groove provides a delivery 619 configured to cooperate with a delivery 318 complementary within the tip member 264 in the same manner as in the previous embodiment. The provision of the axial guide sub 613 also allows for a wider delivery 619, and consequently the front outer guide flow sub 611 is correspondingly narrower than in the previous embodiment.

Other differences in the configuration of the tip member 662 are not particularly relevant to the present invention and merely represent other possible variations. These include the provision of melt discharge grooves 84 configured to cooperate with melt discharge portal 677D as described above.

12A, 12B, 12C, and 12, a non-return valve 860 according to another embodiment of the present invention, configured for the barrel assembly 38 of the injection molding machine 10, is shown. Non-return valve 860 is very similar to that previously described and shown with reference to FIGS. 6A, 6B, 6C, and 6D. Accordingly, only differences in structure and operation between the embodiments are examined and similar reference numerals have been given to configurations common to both embodiments. As before, the non-return valve 860 includes a tip member 762, a ring member 464, and a flange member 766.

Non-return valve 860 is another example of the reconstruction of complementary spigots and guides, with the flange portion 766 configured near the end of the reconfigured screw 756 replacing the flange member 166. Thus, the ring member 464 includes four inner axial guide flows 412 and separate inner spigot flows 414. Tip member 762 includes complementary outer guiding flow 720, and complementary outer spigot flow 710 is provided at the end of reconfigured screw 756.

More specifically, the unique configuration of the ring member 464 of this embodiment is the provision of a spigot sheet 490 configured along the rear of the annular body 94 as a shallow cylindrical bore formed through the rear surface. The inner circumferential surface of spigot sheet 490 provides an inner spigot flow 414. The spigot flow portion 414 is configured to cooperate with the complementary outer spigot flow portion 710 configured along the end of the screw 756 so that the spigot seal therebetween when the ring member 364 is in the ejected position. Establish 122. Likewise, spigot flow 414 is configured to cooperate with guide flow 720 constructed along tip member 762 to provide melt transfer passage 777B when ring member 464 is in the recovery position. . The planar front face of the spigot sheet 490 provides a retention surface 457 that cooperates with the front face 57 of the screw 756 to limit the rearward movement of the ring member 464. Alternatively, this function is provided through the cooperation of complementary retention seals 90, 90 'as described above in the present invention.

Inner guide flow 412 is configured along the inner peripheral surface of four narrow, arcuate and longitudinally extending members. The longitudinally extending member is an arcuate groove, four equally spaced apart, outwardly and laterally diverging (ie toward the front of the ring member 364) through the inner circumferential surface of the annular body 94. And remain from the spigot sheet 490 through the front surface of the annular body 94. Each groove provides a delivery portion 418 configured to cooperate with the outer guide flow portion 720 when the ring member 464 is in the recovery position, defining a melt branch passageway 777C therebetween. Each melt branch passage 777C connects the melt branch passage 777B to the melt discharge portal 777D. The melt discharge portals 777D are each delivered along the front face of the ring member 464 outside the outer surface of the tip flange 81 (i.e., across the tooling flat 104 and the periphery 80). Between the portions of 418. The axial guides 412 run to maintain the ring and tip members 464, 762 in mutual axial alignment as the ring member 464 moves relative to the tip member 762 between the ejection and recovery positions. It is configured to cooperate with the outer guiding flow 720 which is complementary to the pit 123.

Tip member 762 is basically configured as described above except that the functional portion between alignment 70 and front retainer 76 includes only guide flow 720. Other differences in the construction of the tip member 562 are not particularly relevant to the present invention and merely represent other possible variations. This involves the removal of the melt discharge groove 84 due to the narrow tip flange 81, the outer surface of the tip flange 81 being of the ring member 464 to provide the melt discharge portal 777D as described above. And cooperate with the delivery unit 418 along the front face.

As introduced earlier, the front end of the screw 756 is configured to include a flange portion 766 that performs the function belonging to the flange member 166 in advance and an outer spigot flow portion 710 that functions as described above. do. More specifically, the outer circumferential surface of the flange member 766 is configured to cooperate with the barrel bore 48A as shown with reference to FIG. 2 to create an annular melt passageway that allows forward passage of the melt therebetween during recovery. to provide. The front face of the flange portion 766 provides a retention seal 90 configured to cooperate with the complementary retention seal 90 'of the ring member 64 in the ejected position, as described above, to provide the retention of the ring member 64. Limit backward movement and seal in between (ie, close melt passage 777A). Around the end of the screw 756 immediately adjacent to the flange member 766 is a narrow cylindrical band configured to provide the outer spigot flow 710.

13A, 13B, 13C, and 13D, a non-return valve 960 according to another embodiment of the present invention, configured for the barrel assembly 38 of the injection molding machine 10, is shown. Non-return valve 960 is very similar to that previously described and illustrated with reference to FIGS. 12A, 12B, 12C, and 12D. Accordingly, only differences in structure and operation between the embodiments are examined and similar reference numerals have been given to configurations common to both embodiments. As before, the non-return valve 960 includes a tip member 862, a ring member 464, and a flange member 866.

Non-return valve 960 is a reconstruction of a previous embodiment of non-return valve 860 without using face seal 91, with spigot seal 122 complementary on ring and flange members 434, 866. Provided between locations. Thus, flange member 866 includes outer spigot flow 860 and complementary retainer 490 '.

More specifically, the flange member 866 includes a simple annular body 92 (ie, such as a washer) having a planar front side and a back side. As before, the inner circumferential surface of the annular body 92 is configured to provide a complementary alignment 70 'that cooperates with the alignment 70 of the tip member 862 in use. The rear plane of the annular body 92 is a complementary mating surface 57 configured to cooperate with the screw mating surface 57 when positioning the complementary seat portion 72 ′ provided on the bottom of the front surface of the annular body 92. ') Is provided on the seat portion 72 on the tip member 864 to firmly position the flange member 866 therebetween. The remaining portion of the front face of the annular body 92 provides a complementary retaining portion 490 ′ configured to cooperate with the complementary retaining portion 490 defined within the spigot sheet 490 on the ring member 464. Limit the rearward movement of 64. The outer circumferential surface of the flange member 866 is complementary inner spigot flow 810 defined in the spigot sheet 490 on the ring member 464, respectively, in the eject and recovery positions, as described with reference to the description of the preceding embodiments. ) And outer guide flow 820.

The tip member 862 is basically configured as in the previous embodiment except that the guide flow portion 720 is provided along the shallow flange that provides the seat 72 described above.

Referring to Figures 14A, 14B, 14C and 14D, a non-return valve 1060 according to another embodiment of the present invention configured for the barrel assembly 38 of the injection molding machine 10 is shown. Non-return valve 1060 is very similar to that described and illustrated above with reference to FIGS. 3A-3C and 9A-9D. Accordingly, only differences in structure and operation between the embodiments are examined and similar reference numerals have been given to configurations common to both embodiments. As before, the non-return valve 1060 includes a tip member 962, a ring member 964 and a flange member 366.

Non-return valve 1060 is another example of the reconstruction of complementary spigots and guides on ring and tip members 964, 962 and complementary rear retainers 390 on flange members 366, spigot seals The melt 122 is required as a whole during injection without 122 providing a face seal 91 between the ring member 264 and the flange member 366 and the complementary back retention seal 90 and retainer 390, respectively. Provide backflow restriction. Thus, complementary inner and outer alignment spigot flows 909, 914 are constructed along separate portions of the tip and ring members 962, 964. Complementary inner and outer alignment spigot flows 909, 914 have no provision of a running pit 123 therebetween, and instead complementary alignment spigot flows as ring member 964 slides into the ejected position. It is further characterized by the fact that 909 and 914 are configured to be aligned with each other.

More specifically, tip member 962 has some common structural configurations, except that some common structural configurations have the additional ability to cooperatively align and seal with complementary portions provided on ring member 964. It remains essentially unchanged with respect to the tip member 62 of the prior art as shown in Figures 3B and 3C. In particular, the tip member 962 has a spigot flange configured similarly to the retaining flange 73 on the tip member 62 except that its outer surface is configured to provide an outer aligned spigot flow 909. 973). Thus, the outer circumferential surface of the spigot flange 973 provides the spigot flow sub-section, and its tapered front face provides the alignment sub-section 911.

The ring member 964 is also reconfigured to provide a complementary inner alignment spigot flow 914 with the inner circumference of the annular body 94 and its outer surface 96 does not require the use of the piston ring 98. It is constructed similarly to the prior art ring member 64 as shown in Figures 3A, 3B and 3C, except that it is configured to cooperate with the barrel bore 48A in a non-running fit. In particular, the narrow cylindrical band portion along the rear portion of the inner circumferential surface of the annular body 94 is configured like the inner aligned spigot flow portion 914. As before, the inner alignment spigot flow 914 is configured to overlap with the complementary outer spigot flow sub-section when the ring member 964 is in the ejected position, and to cooperate in a parallel and closely spaced relationship with each other. To provide a spigot seal 122 therebetween. Moreover, the inner alignment spigot flow portion 911 is configured to cooperate with the outer alignment sub portion 911 provided on the tapered front face of the spigot flange 973 so that the ring member and tip as the ring member transitions to the injection position. The members 964 and 962 are aligned with each other. In particular, any misalignment between the medial alignment spigot flow 914 and the complementary lateral spigot flow sub-section 910 is such that the medial alignment spigot flow 914 is tapered of the outer alignment sub-port 911. It will be modified as it is pressed to slide along the face.

The flange member 366 includes four conformally spaced melt inlet grooves 376 extending through the outer periphery and between the rear and front surfaces as described above. The inlet groove 367 extending through the retaining surface 390 is particularly relevant to preventing surface sealing from being achieved with the complementary back retaining sealing surface 90 on the ring member 264.

When the ring member 964 is in the recovery position, the melt inlet passage 997A extends along the tip member 962 between the spigot flange 973 and the tip flange 81, the inner circumference of the annular body 94. Between complementary retention portions 90, 390 interconnecting the melt inlet groove 367 to the melt transfer passage 971B formed between the surface and the routing portion 20. The tip flange 81 is further configured to include four melt outlet grooves 84 that cooperate with the melt delivery 971B in use for ejection of the melt as described above.

15A, 15B, 15C and 15D, a non-return valve 1160 according to another embodiment of the present invention configured for the barrel assembly 38 of the injection molding machine 10 is shown. Non-return valve 1160 is very similar to that described and illustrated above with reference to FIGS. 5A-5D and 14A-14D. Accordingly, only differences in structure and operation between the embodiments are examined and similar reference numerals have been given to configurations common to both embodiments. As before, the non-return valve 1160 includes a tip member 1062, a ring member 1064 and a flange member 1066.

Non-return valve 1160 is another example of reconstruction of complementary spigot and guide configured to cooperate with a complementary configured end of a plugged melt duct flow and to align with one another and to provide a spigot seal therebetween. to be. Accordingly, the plug 1109 is configured to include an outer spigot flow sub portion 1111 and an outer aligned flow sub portion 1113 and the melt duct flow portion 1118 includes an inner aligned spigot flow portion 1114. Configured. There are a number of plugs 1109 provided around the front face of the flange member 1066 and corresponding numbers of similarly arranged sealed melt duct flows 1118 extending through the ring member 1064. Additionally, the ring member 1064 has an inner guide that cooperates with the complementary outer guide flow 1110 configured along the tip member 1062 to guide the ring member 1064 between the ejection and recovery positions. 1115 is further configured to include.

More specifically, the tip member 1062 is as shown in FIGS. 5A, 5B, 5C and 5D except that the outer peripheral surface of the flange 1171 is configured as the outer guide flow portion 1110. It is basically the same as the tip member 162 of the first embodiment. Additionally, when the ring member is in the recovery position, the outer guiding flow portion 1110 may pass the melt transfer passageway 1077C provided along the melt duct flow portion 1118 onto the tip member 1062. Arranged to cooperate with a plurality of arcuate routings 1119 configured across the back surface of the tip flange 81 and the front surface of the ring member 1064 to provide a melt discharge passageway 1077D that interconnects 1120. . As before, the routing portion 1120 sends the melt to a melt discharge groove 84 configured along the perimeter of the tip flange 81 during use.

The ring member 1064 is also constructed similarly to the ring member 964 of the previous embodiment, as shown in FIGS. 14A, 14B, 14C, and 14D. As introduced previously, the ring member 1064 includes six cylindrical, conformally spaced, longitudinally aligned melt duct flows arranged between the front and back and inside and outside the outer circumferential surface of the annular body 94. Eastern 1118. The cylindrical back portion of each melt duct flow 1118 is further configured to provide an inner aligned spigot flow 1114 that cooperates with the plug 1109 in use as described below. As introduced earlier, the front face of the ring member 1064 has four conformally spaced, arcuate grooves providing routing portions 1119 that connect the ends of adjacent paired melt duct flow portions 1118 to each other. It is further configured to include. The groove is as described above and in that it extends through the inner circumferential surface of the ring member 1064 to interconnect the routing portion 1120 and the arcuate routing portion 1119 when the ring member is in the recovery position. Is further characterized as.

The flange member 1066 is also configured similarly to the flange member 66 of the first embodiment as shown in FIGS. 5A, 5B and 5C. As introduced earlier, the flange member 1066 is six cylindrical, conformal spaced, ejected to protrude from the front face in a pattern corresponding to that of the complementary melt duct flow 1118 provided along the ring member 1064. It further includes a longitudinally aligned plug 1109. The configuration of each plug 1109 is further characterized in that it has a rear cylindrical portion, a much narrower and longitudinally aligned front cylindrical portion and a transition therebetween. The outer circumferential surface of the rear cylindrical portion provides an outer spigot flow sub portion 1111. As before, the outer spigot flow 1111 is complementary inwardly aligned spigot flow 1114 in an overlapping, parallel and closely spaced relationship when the ring member 1064 is in the ejected position. And spigot seal 122 between them. Likewise, the outer circumferential surface and transition portion of the front cylindrical portion provide an outer aligned flow sub portion 1113. The outer aligning flow sub portion 1113 is configured to cooperate with the inner aligning spigot flow sub portion 1114 such that the melt duct flow portion 1118 and the plug 1109 are in contact with each other as the ring member 1064 enters the injection position. Sort it. In particular, any misalignment between the inner aligned spigot flow 1114 and the complementary outer spigot flow sub 1114 is along the outer aligned flow sub 1111 in which the inner aligned spigot flow 1114 is formed. It will be modified as it is pressed to slide. Referring to Figure 15C, the front cylindrical portion of plug 1109 remains engaged inside the end of each melt duct flow 1118 to maintain overall alignment therebetween when the ring member is in the recovery position. Moreover, the annular space between the outer aligning flow sub portion 1113 and the complementary inner aligning spigot flow portion 1114 provides a melt transition passage connecting the melt inlet passage 1077A with the melt transition passage 1077C. do.

Other differences in the configuration of the flange member 1066 are not particularly relevant to the present invention and merely represent other possible variations. In particular, the flange member 1066 further includes four shallow, conformal spaced melt inlet grooves 1067. The configuration of the inlet groove 1067 does not prevent achieving the face seal 91 between the complementary retention seals 1090, 1091 ′. However, the face seal 91 is considered to be supplementary and thus is not a required configuration.

Although the spigot seal is preferably characterized as comprising a small gap between the complementary spigot portions, the resulting seal may also be achieved with no gaps in between or with a suitable interference fit. The foregoing may require proper tapering of complementary spigot portions or some other means for their initial mutual coupling.

Of course, other field modifications have a flange member integrally formed with the tip portion, a tip and flange member integrally formed at the end of the screw, and a tip flange 81 detachable with the tip member for easy repair of the ring member. It may also include.

Despite the fact that the various embodiments of the non-return valves of the present invention described above are configured for use inside the barrel assembly 38 of the injection molding machine 10, no such limitations on their general use are implied. For example, the non-return valve of the present invention may be used at any location along a molding material flow passage (e.g., in a hot runner nozzle assembly of a hot runner shooting pod assembly, etc.), or in another type of forming system (e.g., Extrusion, die casting, etc.), when molding different types of molding materials (e.g. thermoplastics), differently for use in moldings using alternative molding processes (e.g., complete liquid melts). It may be configured.

All of the above-mentioned US and foreign patent documents are incorporated by reference into the detailed description of the preferred embodiments by this document.

Individual configurations, indicated by outlines or blocks in the accompanying drawings, are all known in the molding art, and their specific construction and operation are not critical to the operation or the best mode for carrying out the invention.

Although the invention has been described in connection with what is presently considered to be the presently preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. On the contrary, the invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims (35)

Non-return valves 160, 260, 360, 460, 560, 660, 760, 860, 960, 1060, 1160 for use in the flow channel 48 of the forming system 10, The valve body 162, A ring member 164 surrounding an intermediate portion of the valve body 162 such that the valve body 162 and the ring member 164 can reciprocate longitudinally relative to each other; A plurality of melts disposed along the valve body 162 and the ring member 164 when the valve 160 is in an open configuration with the ring member 164 positioned to the front restriction to allow flow through the melt. A melt passageway 177 that can be configured along valve 160 between the flow surfaces 84, 90, 90 ′, 110, 114, 118, 120, and The valve 160 may be in the closed configuration with the ring member 464 positioned at the rear restriction to provide a spigot seal 122 that substantially blocks backflow of the melt through the melt passageway 177. And at least a pair of complementary spigot portions 110, 114 on the melt flow surfaces 110, 114 configured to join in substantially spaced apart, overlapping and parallel arrangements when substantially adjacent, The valve body 162 includes a first retainer 166 disposed at the rear portion to limit the backward movement of the ring member 164 along the valve body 162, The valve body (162) includes a second retainer (76) disposed in the front portion to limit the forward movement of the ring member (164) relative to the valve body (162). 2. The non-return valve as claimed in claim 1, wherein the non-return valve is disposed between the valve body 162 and the ring member 164 to guide the ring member 164 in coaxial alignment with the valve body 162 as it moves between an open and closed configuration. Non-return valve further comprises a guide (110, 116) disposed in. The non-return valve as recited in claim 1 wherein the non-return valve aligns the ring member 964 and the valve body 962 with each other as the pair of complementary spigot portions 910, 914 engage with the backward movement of the ring member 964. Non-return valve further comprising a guide (911, 914) disposed between the valve body (962) and the ring member (964). 4. The valve 160 of claim 2 or 3, further comprising a pair of complementary face seal surfaces 90, 90 'configured in parallel planes provided on the rear of the ring member 164 and on the front of the first retainer. A non-return valve in which a face seal 91 can be configured therein to help block backflow of the melt flow through the melt passageway 177 when the) is in the closed configuration. 5. A non-return valve as claimed in claim 4, wherein the valve body (162, 362) comprises at least one cylindrical flange (173, 373, 374) disposed between the retainers (76, 166). 6. The guide portion (110, 116, 911, 914) of claim 5 along a portion of the outer circumferential surface of at least one cylindrical flange (173, 373, 374) and a portion of the inner circumferential surface of the ring member (164). Non-return valve comprising a complementary guide surface (110, 116, 911, 914) configured along. 7. A non-return valve as claimed in claim 6, wherein the guide surface (110, 116) is configured to provide a running fit (123) between the valve body (162) and the ring member (164). 6. A non-return valve as claimed in claim 5, wherein at least one of the plurality of melt flow surfaces (110, 114) is configured along a portion of the outer peripheral surface of the at least one cylindrical flange (173, 373, 374). The at least one groove 120, 319 of claim 8, wherein at least one of the plurality of melt flow surfaces 120 is disposed on an outer surface of the valve body 162, 362 between the retainers 76, 166, 266. , Non-return valve configured along the surface of 320). 10. A non-return valve as set forth in claim 9, wherein said at least one groove (120, 319, 320) extends circumferentially around the valve body (162) adjacent said flange (173, 373, 374). 10. A non-return valve as claimed in claim 9, having a plurality of grooves (419) disposed through the outer circumferential surface of the cylindrical flange (473, 474) in equidistant relationship. 6. A non-return valve as set forth in claim 5, wherein at least one of the plurality of melt flow surfaces (114, 914) is configured along a portion of the inner peripheral surface of the ring member (164, 964). 13. The non-return valve of claim 12, wherein at least one of the plurality of melt flow surfaces (118) is configured along a surface of at least one groove (118) disposed on an inner surface of the ring member (164). 14. A non-return valve as set forth in claim 13, wherein there are a plurality of grooves (118) disposed in equidistant relation around the inner surface of the ring member (162). 15. The melt flow surface (110, 114) of any of claims 8-14, wherein the at least one pair of spigot portions (110, 114) is on the outer surface of at least one flange (173, 373, 374). A non-return valve configured along at least a portion of and along an inner surface of the ring member 164. 16. The ratio of claim 15 wherein there are a plurality of pairs of spigot portions 214, 216, 310, 311 disposed on the outer surface of at least one flange 373, 374 and along the inner surface of ring member 164. Return valve. 17. A non-return valve as set forth in claim 16, wherein said at least one pair of spigot portions (110, 112) are disposed adjacent to a face seal surface (90, 90 '). 5. A non-return valve as claimed in claim 4, wherein the first retainer (166) is an annular body held around an end of the valve body (162). 19. A non-return valve as claimed in claim 18, wherein the first retainer (366) comprises a melt inlet groove (367) configured between the rear and front surfaces of the first retainer. 15. The method of any of claims 8-14, wherein the first retainer 866 has an outer peripheral surface thereon providing a melt flow surface and at least a portion thereof being one of the at least one pair of spigot portions 810. A non-return valve, which is an annular body held around an end of a valve body 162 providing a. 2. A non-return valve as claimed in claim 1, wherein the ring member (164) further comprises a groove (95) around its outer surface (6) for receiving a piston ring (98). 22. The non-return valve of claim 21, further comprising a pressure port (97) extending between the melt flow section (118) and the piston ring groove (95). 23. A non-return valve as set forth in claim 22, further comprising a sub ring (100) in a groove (95) below the piston ring (98). The non-return valve as claimed in claim 8, wherein the first retainer (766) is configured on one end of the screw (756). 25. The non-return valve of claim 24, wherein an outer circumferential surface (710) around the end of the screw (756) provides a melt flow surface, at least a portion of which provides one of at least a pair of spigot portions. 25. The non-return valve of claim 24, wherein the first retainer (766) comprises a face seal surface (90 '). The inlet according to any one of claims 1 to 3, wherein at least one of the plurality of melt flow surfaces 1114 is arranged between the inner and outer peripheral surfaces of the ring member 1064 and disposed through an end thereof. Configured along the inner circumferential surface of the longitudinally aligned melt duct 1118 with the at least one pair of spigot portions having complementary shaped plugs arranged on the retainers 1066 of the valve body 1062. A non-return valve provided by at least a portion of the melt flow surface (1114) in coordination with complementary spigot portions (1111) provided on the outer circumferential surface of 1109. 28. The non-return valve of claim 27, wherein the melt duct (1118) extends through the valve member (1064). 28. A non-return valve as set forth in claim 27, wherein the plurality of melt ducts (1118) and plugs (1109) are arranged around the ring member (1064) and the rear retainer (1066) in an equiangularly spaced and longitudinally aligned arrangement, respectively. 30. The non-return valve of claim 29, wherein each distal end of at least two of the plurality of melt ducts 1118 is connected to each other by at least one groove configured through an inner surface of the ring member 1064 adjacent the distal end. . 28. The non-return valve of claim 27, wherein the plug (1109) further comprises a front portion (1113) configured to be connected within the inlet end of each melt duct (1118) to maintain overall alignment therebetween. A valve body for a non-return valve (160) according to any one of the preceding claims. Ring member for a non-return valve (160) according to any one of the preceding claims. Improved non-return valves 160, 260, 360, 460, 560, 660, 760, 860, 960, 1060, 1160 for use within the flow channel 48 of the forming system 10, Melt through melt passageway 177 further comprising a spigot seal 122 configurable between at least first and second movable members 162, 164 of the non-return valve when the non-return valve is in a closed configuration. Substantially prevents backflow of the spigot seals and the at least one pair of complementary spigots 110 configured on the first and second valve members 162, 164 in a substantially closely spaced, overlapping and parallel arrangement. 114) non-return valve provided between. 35. A non-return valve as set forth in claim 34, configured for use in a barrel assembly (38) of a metal injection molding machine (10).

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