GUILLOTINE SHUT-OFF VALVE FOR INJECTION MOLDING

Description

“Guillotine Shut-Off Valve for Injection Molding” in the name of INglass Spa with sole shareholder, with headquarters in S. Polo di Piave (TV) Designated Inventors: Massimo Rossi, Alessandro Dario DESCRIPTION 5 The invention relates to a guillotine shut-off valve for controlling a flow of molten material during injection molding. It is known to control the flow of molten material exiting a gate into a cavity. mold by means of a stem (pin or shutter) which is linearly movable back and forth with movement consistent with the flow of the molten material. The presence and movement 10 alternating of the stem however increases the disturbances on the flow creating accumulation zones and stagnation of the material, so much so that for example the operation of changing the color of the material injected requires multiple purge injections with significant waste of material. oblique ones as in EP520345 have the defect of pushing the material against the surface inside the canal, compressing it further until the exit. This effect of 15 crushing causes the appearance of defects on the final piece. In an attempt to solve the problem, the stem shutter was replaced by a slide valve placed at the material exit gate. This solution, adopted for the simultaneous opening and closing control of multiple injectors placed in line and controlled by a single actuator, is shown for example in EP1409222 (fig. 13). 20 However, a single moving guillotine causes the material to be crushed towards the perimeter of the gate orifice, which is at a lower temperature, thus causing defect in the printed product. WO2024095073 shows a better solution, i.e. using a rotor to control the shutter elements. The WO2024095073 system can also be improved. 25 Main object of the invention, defined in the attached claims where those employees define advantageous variants, is to improve this state of the art. A particular aim is to improve the actuation of the moving shutter parts. At least one purpose is achieved by a shut-off valve to control a flow of molten material exiting from a gate into a mold cavity, the valve 30 including: • a channel, for the molten material, which extends along a first axis up to the gate, • a shutter mounted movably so that one free end of the shutter can move towards, and reach, a point inside the canal to strangle and / or close the channel thus regulating the flow, • an actuator element having a portion coupled to the shutter so that a movement of the actuator element causes a movement of the shutter away from and / or towards said point, • a lever with a first and second end and a fulcrum of rotation, where 5 the first end is connected to the actuator element, the second end is connected to the shutter, and the rotation fulcrum is rotatably pivoted to a mold component, so that a movement of the actuator element results in a rotation of the lever around an axis passing through the fulcrum and the second end pushes or pulls 10 the shutter and make it move. The lever has the advantage of simplifying the structure of the shutter drive, for example e.g. simplifying the motion relays or the kinematic chain from the actuating element to the shutter. Furthermore, the lever allows you to multiply or scale the travels of the various components of the kinematic chain towards the shutter. 15 Preferably, for compactness, the actuator element is a rotating element, more preferably placed near the gate. More preferably the first end is coupled to the rotating element eccentrically with respect to the rotation axis of the rotating element. To simplify the kinematic chain, preferably the swivel element comprises 20 a profile (e.g. eccentric or a cam or a groove) to which it is coupled sliding the first end, and the profile has a development such as to convert a rotation of the rotating element of a certain angle in a shutter movement. Preferably the profile has, for example, a development: 25 circular and concentric to the axis of rotation of the rotatable element, or spiral converging towards the axis of rotation of the rotating element, or radial with respect to the axis of rotation of the swivel element. In a preferred variant, said profile is a groove obtained on the element rotatable, preferably on the outer perimeter. 30 The drive system for the valve shutter elements is independent of the number and configuration of the shutter elements, which can advantageously to be more than one. In a preferred compact variant, the swivel element extends around (e.g. also surrounds) the first axis and the channel; in particular the rotating element comprises a ring surrounding the first axis and the canal. In a preferred variant, the rotatable element is rotatably mounted on a member fixed (i.e. stationary) that is fixed to the mold (e.g. fixed to or on a component or plate) 5 of the mold) and in particular it may comprise a surface that forms a portion of the cavity of die. In a preferred variant, the rotating element comprises a ring or crown coaxial to the first axis (and e.g. also to said fixed element), and e.g. said profile is 10 a raised groove or lug or cam machined into the crown or ring. In a preferred variant, the rotatable element has an axis of rotation which is • parallel to the first axis, in particular for maximum compactness the element swivel has a rotation axis coaxial to the first axis, or • orthogonal to a plane passing through (and incident on) the first axis. 15 In a preferred variant, the valve comprises two or more shutter elements whose respective second axes are coplanar and arranged • radially around the said point, or • like the diagonals of a polygon (regular or not), where the said point identifies the center of the polygon. 20 In a preferred variant, the valve comprises only two movable shutter elements along the sides of an angle with vertex at the said point, where the plane of the angle is orthogonal to the first axis or passing through the first axis. In the case of two or more shutter elements, this point becomes a common point of convergence, or closing point of the canal, for the translation of the obturator elements 25 (and for the second axes). In a preferred variant, the valve comprises three or more shutter elements and respective second axes are arranged like the edges of an imaginary pyramid, called point of convergence forming the vertex of the pyramid. In a more preferred variant, this imaginary pyramid is arranged so that its base intersects the first axis and 30 the channel, more specifically, is orthogonal to the first axis. In a preferred variant the first end comprises a first protruding pin slidingly engaged in said groove. In a preferred variant the lever is L-shaped. In a preferred variant the second end comprises a second pin protruding pin engaged in a seat of the shutter. More preferably the second pin protruding part is engaged in a rotating and / or sliding manner in said seat. In a preferred variant one or each shutter has the shape of a straight stem, in particular having one free end while the opposite end is coupled to a 5 ends of the lever. Preferably the shutter is mounted so that it can be moved along a respective second axis, for Construction simplicity. The second axis can be orthogonal or inclined at an angle acute or obtuse with respect to a plane passing through the first axis, or with respect to the first axis. In this case, a movement of the actuator element causes a rotation of the 10 lever around an axis passing through the fulcrum and the second end pushes or pulls the shutter to make it translate along the second axis from and / or towards said point. How much defined above for the said shutter movement also applies to a translation of the shutter. In a preferred variant, which improves the performance of the injector, the valve 15 comprises two or more shutter elements which are actuated by the rotatable element and mounted movably along a respective second axis inclined at an acute angle with respect to the first axis and so that one free end of each shutter can move and converge towards the same point of convergence inside the canal, 20 the free ends of the shutter elements can match in correspondence with the said convergence point to compose a blocking bulkhead for the molten material. The advantages of the invention will be made even clearer by the following description of a preferred actuator, in which  Fig. 1 shows a sectional view of a shut-off valve; 25  Fig. 2 shows a three-dimensional view of assembled valve components;  Fig. 3 shows a three-dimensional view of the components of fig. 2 in exploded view;  Figs. 4-5 show details of the components in Fig. 2;  Fig. 6 shows a sectional view of a second shut-off valve;  Fig. 7 shows a three-dimensional view of the valve components of Fig. 6. 30 In the figure equal elements are indicated by equal numbers, and in order not to crowd the drawings sometimes only some elements are numbered. Referring to figure 1, the tip 18 (or tip) of a well-known injector is shown. 10 used to inject molten material into a mold cavity 12. The injector 10 of It is usually mounted inside one or more 500 plates that make up the mold and which is fixed to a well-known distribution manifold for the molten material (the so-called manifold, also mounted inside the plates 500, not shown). The injector 10 comprises a hollow body 14 innermost which defines an axial cavity 16 which extends longitudinally along a central Y-axis. The Y-axis is preferably also the polar symmetry axis for the 5 tip 18. The tip 18 rests on a mold insert 20 with an orifice that determines a gate 98, and the molten material can flow in cavity 16 to gate 98. Overall, the construction of injector 10 is known, and there is no need to repeat it. Unlike the known injectors, there is no stem shutter in cavity 16 (valve pin). The system for regulating the flow of molten material passing through the 10 gate 98 is illustrated in detail in fig. 2 and following. In a tunnel 30 of the insert 20, or of another plate connected to it, a shutter 32 in the preferred form of a straight stem 34 having a free end 36 while the opposite end 38 is coupled to one end 92 of a lever 90. The tunnel 30 and the shutter 32 preferably have a complementary shape. 15 The lever 90 has an opposite end 94 which is in turn coupled to a means actuator 100, an example of which is shown in fig. 2. The central part of the 90 lever has a rotation fulcrum which allows the lever 90 to rotate around an axis W. Preferably the rotatable coupling between the central fulcrum and the plate is facilitated by a pin 96 protruding from the body of the 20 lever 90. The actuator means 100 is in the preferred form of a rotatable ring or disk 52, preferably installed in a cavity of the insert 20 around the gate 98. The actuator means 100 can rotate about an axis Y2, preferably parallel or coincident with the Y axis. 25 The end 94 is engaged in a radial groove 50 formed in the peripheral edge of the ring 52, while the end 92 is movably inserted into a seat 37 of the shutter 32. The disc 52 has an external toothing 54 engaged on a toothing 56 present on a shaft 58 that can be moved back and forth along an axis W3. By moving the shaft 58, by any known means, the ring 52 can be rotated around 30 to the Y2 axis. Rotation of the ring 52 moves the radial groove 50, which moves the end 94 and rotates the lever 90 around the axis W (see arrow F in fig. 5). Therefore end 92 also rotates around axis W and pulls or pushes end 38 of the shutter 32 back and forth. You can then push the end 38 back and forth along the Z axis obtaining a proportional sliding of the shutter 32 inside the tunnel 30, which results in the greater or lesser protrusion of the end 36 inside the gate channel 98. This protrusion determines the degree of closure of gate 98. Preferably the shaft 58 is also installed in a cavity of the insert 20 or of a plate 500 or a mold component. 5 In the example the angle between the Z-axis and the Y-axis is right, but not necessarily: it could be sharp or dull. In the example the W3 axis is orthogonal to a plane passing through the Y2 axis but not necessarily. Another example of actuation for the shutter 32 is shown in fig. 6 and 7. Here it is 10 illustrates a variant of the system that allows more than one shutter to be moved at a time, in the example two 32-inch opposing shutters that can move along the same Z-axis. Each shutter 32 is coupled at diametrically opposite points of the ring 52, which this time has two radial grooves 50 at those points. However, it is possible to move more than two shutters simultaneously. 15 by installing more actuator means 100 in the same ring 52 or more rings 52. In the examples the angle between the Z-axis and the Y-axis is right, but not necessarily: It could be sharp or blunt. In fact, it is sufficient to orient the means differently. actuators 100 to obtain different inclined trajectories of a shutter 32. E.g. three or more shutters 32 could be arranged like the edges of a regular pyramid having 20 axis coincident with the Y axis. * * *

Claims

CLAIMS 1. A gate valve for controlling a flow of molten material from a gate into a mold cavity, comprising: • a channel for the molten material extending along a first axis to the gate, • a shutter movably mounted so that a free end of the shutter can move to and reach a point within the channel to restrict and / or close the channel thereby regulating said flow, • an actuating member having a portion coupled to the shutter so that movement of the actuating member causes movement of the shutter to and / or to said point, • a lever having first and second ends and a pivot point, where the first end is connected to the actuating member, the second end is connected to the shutter, and the pivot point is rotatably pivoted to a mold component,so that a movement of the actuating element causes the lever to rotate around an axis passing through the fulcrum and the second end pushes or pulls the bolt and causes it to move.

2. A valve according to claim 1, wherein the actuating element is a rotatable element.

3. A valve according to claim 2, wherein the first end is coupled to the rotatable member eccentrically with respect to the axis of rotation of the rotatable member.

4. Valve according to claim 2 or 3, wherein the rotatable element comprises a profile to which the first end is slidably coupled, and the profile has a development such as to convert a rotation of the rotatable element by a certain angle into a movement of the shutter in one direction of movement.

5. Valve according to claim 1 or 2 or 3 or 4, wherein the first end comprises a first protruding pin slidably engaged with said profile.

6. Valve according to claim 1 or 2 or 3 or 4 or 5, wherein the second end comprises a second protruding pin engaged in a seat of the shutter.

7. Valve according to claim 6, wherein the second protruding pin is rotatably and / or slidably engaged in said seat.

8. Valve according to any of the preceding claims, wherein the lever has an L-shape. Eng. Massimiliano Citron (Registration No. 1215B) 9. A valve according to any of the preceding claims, wherein the shutter is movably mounted to translate along a respective second axis and coupled with the lever so that the shutter can translate along the second axis from and / or towards said point so that a free end of the shutter can reach said point.