Ejector rod for ejecting molded parts

Abstract

The invention relates to an ejector pin for ejecting a molded part from a casting tool. The mandril comprises a shaft having a shaft longitudinal axis, where the shaft has one or more recesses at least along a partial section, where the one or more recesses extend substantially in a helical manner about the shaft longitudinal axis.

Description

TECHNICAL FIELD

[0001] The present invention generally relates to a casting tool, for example to an ejector pin for ejecting a molded part. BACKGROUND

[0002] In injection molding and die casting technology, for example for molding plastic and low-melting metal alloys, the general task is to remove the solidified molded part from the mold at the end of the casting operation. For this purpose, one or more ejector pins are often used, which are arranged on a movable support plate, each of which extends through a hole into the mold; when the ejector pin is not actuated, the ejector pin usually ends in a face side that is flush with the inner wall of the mold.

[0003] After opening the casting tool, the casting is ejected by moving the support plate with the one or more ejector pins in the direction of the mold, as a result of which the one or more ejector pins penetrate the mold, thereby ejecting the molded part. Ejector pins are known, for example, from EP 3 722 068 A1 or DE 20 2004 018 293 U1.

[0004] The shaft of the ejector pin is designed to be inserted into a hole or recess of the mold. As a result, the ejector pin can be introduced into the mold at a desired location to eject the casting or molded part and then be removed therefrom. In short, the ejector pin forms a body that can be inserted into the mold and can be removed from the mold and is at least temporarily mounted in the mold, for example, in a floating manner. In particular, the outer contour of the ejector pin can be designed to be substantially complementary to the inner contour of the mold, as a result of which a form fit can essentially be achieved, but there can be a certain hollow space between the ejector pin, in particular the shaft of the ejector pin, and the mold, in particular the recess or hole of the mold.

[0005] This results in the fact that, in particular during the introduction of the casting material into the mold cavity, air cannot or cannot completely flow out or escape. This further results in the fact that undesirable air can be present in the molded part, so that the mold cavity is not completely filled with casting material, in particular in the area of the ejector pin. As a result, undesirable defects are present in the cast molded part.

[0006] In order to be able to enable the undesirable air to escape more effectively from the molded part via the hollow space or through the hollow space between the ejector pin and the mold, ejector pins with a so-called venting function are known in the prior art.

[0007] However, for this type of ejector pin, it is required that no casting material or other undesired material accumulates between the shaft of the ejector pin and the wall of the mold. If casting material is introduced into the mold cavity, not only air, but also casting material can enter the hollow space in an undesired manner. The venting function known from the prior art can even enhance this effect. Thus, it is further caused that the mold, in particular the bore, and / or the shaft of the ejector pin can be contaminated with casting material. This contamination increases the maintenance and / or cleaning effort associated with the mold, the bore and / or the shaft. This means in particular a downtime in the production of molded parts. SUMMARY

[0008] It is an object of the present invention to avoid or reduce the above-mentioned disadvantages of previously known ejector pins. The invention relates to a device according to the independent claim 1. The dependent claims relate to preferred embodiments.

[0009] The invention relates to an ejector pin for ejecting a molded part from a casting tool, the ejector pin comprising a shaft having a shaft longitudinal axis. The shaft has one or more recesses along at least a partial segment. The one or more recesses extend in a helical manner or substantially in a helical manner around the shaft longitudinal axis.

[0010] The shaft can be substantially a body of revolution. For example, the shaft can be substantially cylindrical or substantially conical. The shaft can be substantially an extruded body. The shaft can be substantially pyramidal. The shaft can be substantially cuboid. The shaft can be substantially rectangular. The shaft can be substantially parabolic.

[0011] The shaft can comprise one or more shaft segments. In case of multiple shaft segments, these shaft segments can have different shapes. Thus, a shaft segment can be cylindrical, conical, frustoconical or conical. Alternatively, at least one shaft segment can extend over the (entire) length of the shaft. The multiple shaft segments can be connected to each other, or arranged next to or spaced apart from each other.

[0012] The shaft can comprise at least a first, a second and a third shaft segment, wherein the second shaft segment is adjacent to an end of the first shaft segment and adjacent to an end of the third shaft segment. The first shaft segment is substantially cylindrical and has a first diameter. The third shaft segment is substantially cylindrical and has a third diameter. The second shaft segment is substantially frustoconical or conical and is designed to be a transition between the first shaft segment and the third shaft segment. This transition can be a stable or continuous transition. In simple terms, in this stable or continuous transition, there is no jump in the cross section of the second shaft segment. In other words, the second shaft segment has a fourth and a fifth diameter, wherein the fourth diameter substantially corresponds to the first diameter and the fifth diameter substantially corresponds to the third diameter. Alternatively or in addition, the second shaft segment has an opening angle. This opening angle is designed to be the transition or is the transition.

[0013] For example, the ratio of the first diameter to the third diameter can be between 1.1 and 4, preferably between 1.5 and 2.5.

[0014] During operation, the longitudinal axis of the shaft typically extends along the insertion direction of the shaft. It can be the axis of symmetry of the shaft. The longitudinal axis of the shaft can be at least one axis of rotation of the shaft. The longitudinal axis of the shaft can (e.g., similar to a static rod) include a rod axis. The rod axis can include the gravity axis of the shaft. The rod axis can include the line connecting the geometric center of gravity or the center of mass of the shaft's cross-section. The shaft can be composed of different materials or material compositions. The shaft can include different materials or material compositions with different material strengths or hardnesses. The hardness can be Rockwell (HR) hardness. Hardness can be determined according to EN ISO 6508-1. Hardness can be determined using HRC.

[0015] The push rod may further include a head. The head may be integrally formed on the shaft. The shape of the head allows the push rod to be mounted in a unique mounting position within the complementary support plate. The head may have an anti-rotation device, ensuring the push rod is mounted in a non-rotatable manner during installation into the complementary support plate. Furthermore, the head may have a pre-centering device. The head may include a support surface on its underside for support on the support plate. The head and the shaft may have different material strengths or hardnesses. The shaft may have a higher material strength or hardness than the head.

[0016] As described above, the shaft has one or more recesses at least along a portion of the shaft. Specifically, the shaft may have at least one recess along the portion of the shaft. Alternatively, the shaft may have multiple recesses at least along the portion of the shaft.

[0017] The segment may be a section or segment in the longitudinal direction of the shaft. Apart from the recess, the segment may be generally cylindrical. The segment may be adjacent to one end of the shaft, particularly the end facing away from the head of the push rod.

[0018] The shaft is designed to shorten from the free end to accommodate the mold. In some embodiments, the length of the extended portion is 50% to 80% of the shaft length, preferably between 59% and 69%. This allows the remaining portion to account for approximately half (e.g., between 45% and 55%) of the remaining shaft length even after the shaft is shortened.

[0019] The segment may include one or more segments. In the case of multiple segments, these segments may be connected to each other, adjacent to each other, or spaced apart.

[0020] As described above, the one or more recesses extend in a helical or substantially helical manner around the longitudinal axis of the shaft. The helical shape can be a threaded line or a coiled shape. In the case of a cylindrical shaft, the helical shape can be described as a curve wound around a cylindrical shell at a constant angle. As those skilled in the art will know, a helix can be described by its pitch height (the distance along the cylindrical axis when the helix rotates a full revolution like a thread), its angle of inclination (also called the pitch angle), or its degree of inclination (a straight line with a corresponding degree of inclination obtained when the cylindrical shell with the helix unfolds into a plane).

[0021] The one or more recesses may extend along a generally helical, threaded, or coiled distance. This distance may extend along the shaft surface. This distance may extend along the segment. This distance may be spaced apart from the segment or from the shaft surface. The segment may be the shaft surface.

[0022] The one or more recesses can be obtained by removing or eliminating material from the original shape of the shaft, for example, by grinding. The original shape of the shaft can represent the shape of a shaft without recesses. The one or more recesses can be one or more notches. The one or more recesses can be produced by a grinding process. The one or more recesses can be produced during the production of the shaft. The recesses can have a generally constant shape or cross-section along the segment. The one or more recesses can include at least one cross-section.

[0023] The cross section is preferably oriented in the normal plane of its length or the normal plane of its longitudinal direction. The cross section may be oriented perpendicular to the longitudinal axis or its length.

[0024] The helical shape of the one or more recesses may have or contain an inclination angle. In the case of multiple recesses, these recesses may have the same inclination angle. Alternatively, these recesses may each have a different inclination angle. Preferably, the inclination angle of the one or more recesses is constant along the longitudinal axis of the shaft. Alternatively, the inclination angle may be constant in some segments and / or dependent along the longitudinal axis of the shaft.

[0025] The helical shape of each recess preferably has a pitch height and / or an inclination. The pitch height may be greater than, equal to, or less than the length of the segment.

[0026] In the case of multiple recesses, these recesses can be arranged spaced apart from each other. The spacing can extend over at least a portion of the segment.

[0027] In some embodiments, the one or more recesses may be generally concave with respect to a cross section perpendicular to the longitudinal axis of the shaft. The one or more recesses may be generally concave in certain segments with respect to a cross section perpendicular to the longitudinal axis of the shaft.

[0028] In other embodiments, the cross-section of the one or more recesses relative to the longitudinal axis of the shaft may be generally planar or linear. The cross-section of the one or more recesses relative to the longitudinal axis of the shaft may be generally planar or linear in segments.

[0029] One or more of the recesses may be planar or straight in segmental cross-section relative to the longitudinal axis of the shaft, and may be concave in segmental cross-section relative to the longitudinal axis of the shaft. At least one of the recesses may be substantially planar or straight in segmental cross-section relative to the longitudinal axis of the shaft. At least one other recess may be substantially concave in segmental cross-section relative to the longitudinal axis of the shaft.

[0030] The concave shape may be or includes a generally circular arc or parabolic shape.

[0031] The arc shape may have or represent a radius between 20 and 30 mm. The arc shape may include a radius. The ratio of the radius to the radius of the axis may be, for example, between 4 and 26, preferably between 10 and 20.

[0032] The original shape of the one or more recesses relative to the unrecessed portion of the shaft can represent a recess between 0.01 mm and 0.03 mm. The original shape of the one or more recesses relative to the unrecessed portion of the shaft can represent a recess of approximately 0.02 mm (at the lowest point). The original shape of the one or more recesses relative to the unrecessed portion of the shaft can represent a recess of 0.02 mm ± 0.003 mm. The accuracy of the recesses (radial along the shaft radius) is preferably less than 5 μm. This accuracy can be achieved over the length of the segment using a grinding process. This further helps to avoid contamination and improve self-cleaning performance.

[0033] The one or more recesses relative to the original shape of the shaft without recesses may represent or include recesses between 0.1% and 2.0% of the radius of the shaft.

[0034] The one or more recesses can be multiple recesses. In particular, the number of recesses can be odd. This allows the recesses to be evenly distributed on the circumference of the axis, and two recesses will not be opposite each other relative to the circumference of the axis. In particular, there can be 3, 5 or 7 recesses.

[0035] The recesses among the plurality of recesses may have or include the same tilt angle.

[0036] The plurality of recesses may have multiple tilt angles. At least one of the plurality of recesses, a first recess, may have a first tilt angle. At least one of the plurality of recesses, a second recess, may have a second tilt angle different from the first tilt angle. This allows the spirals to intersect, thereby further improving ventilation performance.

[0037] The signs and / or absolute values ​​of the first and second tilt angles may be different. A helix with the first and second tilt angles may have the same degree of helix (i.e., tilt angles with the same sign) or opposite degrees of helix (i.e., tilt angles with different signs). The amount or absolute value of the first tilt angle may be the same as or different from the amount or absolute value of the second tilt angle.

[0038] The first tilt angle can be a multiple of the second tilt angle. This multiple can be an approximate integer multiple. The approximate integer multiple can be rounded to 2, 3, or 4.

[0039] The shaft may also include a coating. The shaft may also include a coating on the specified sections. The coating may be a low-friction coating. The coating may include a friction value between 0.1 and 0.15.

[0040] The coating may include a carbon layer. The coating may include an amorphous carbon layer, particularly a diamond-like carbon (DLC) layer. This allows for maintenance-free or low-maintenance use of the pushrod.

[0041] The shaft may also include a front face, wherein the front face reproduces the shape of a molded part or a casting. The front face may be perpendicular to or inclined to the longitudinal axis of the shaft.

[0042] The shaft may also include one or more circumferential grooves. This can further help prevent contamination and improve self-cleaning performance.

[0043] For example, the groove may extend or be oriented substantially in a plane perpendicular to the longitudinal axis of the shaft. Alternatively or additionally, the groove may extend or be oriented tangentially along a circumferential segment of the shaft.

[0044] For example, the groove can be arranged at the end of a segment. The groove can be located between two segments. The groove can be located between two segments and can be connected to one end of a first segment and one end of a second segment. In the case of multiple grooves, these grooves can be connected to each other, adjacent to each other, or spaced apart from each other. Alternatively or additionally, the groove can be connected to, adjacent to, or spaced apart from at least one recess.

[0045] The groove may be designed to have a fluid connection with at least one of the recesses. The groove may be designed to have a fluid connection with or between at least one recess of the first segment and at least one recess of the second segment.

[0046] The groove, relative to a cross-section parallel to the longitudinal axis of the shaft, can be segmentally planar or linear. Alternatively, it can be segmentally concave relative to a cross-section parallel to the longitudinal axis of the shaft.

[0047] The concave shape of the groove can be or includes approximately circular arc, elliptical, or parabolic.

[0048] The arc shape of the groove can have a radius, for example, between 1 mm and 2 mm.

[0049] The groove, relative to the original ungrooved shape of the shaft, can have a depth between 0.02 mm and 0.3 mm. This groove can represent a depth (at the lowest point) approximately 2 to 10 times the depth of the aforementioned recess from the original ungrooved shape of the shaft.

[0050] The present invention also relates to a push rod assembly for use with a mold, the assembly comprising at least one push rod according to the invention and a support plate designed to receive the push rod in a bore. The push rod assembly may also be designed to have a fluid connection between the bore and the mold. The fluid connection may be an air connection. The fluid may be air and / or casting material.

[0051] The mold cavity can at least partially reproduce the female mold of the mold. The mold cavity can be adjacent to the ejector pin. The mold cavity can be at least partially defined by the ejector pin.

[0052] The hollow space can also be designed to allow the push rod to move at least partially. The hollow space can be designed to allow the push rod to move at least partially within at least a segment of the hollow space. Mobility can be translational mobility. Mobility can be rotational mobility. Mobility can be both translational and rotational mobility.

[0053] The ejector assembly may also include at least one mold half. The mold half can at least partially reproduce the mold cavity.

[0054] The at least one half-mold may include a through hole. The through hole may include a hollow space.

[0055] The ejector pin according to the invention is preferably compatible with other ejector pins. This allows the ejector pin or shaft disclosed herein to be used without adjusting the support plate or mold.

[0056] The ejector pin according to the invention, having a helix extending around the circumference of the shaft, allows the load to be evenly distributed around the circumference of the shaft (e.g., due to friction between the shaft and the inner wall of the bore), resulting in uniform wear. Furthermore, the ejector pin according to the invention allows for the reduction or avoidance of contamination, particularly due to unwanted filler or casting material, through the helical shape of the recess. In other words, the generally helical recess has a self-cleaning effect compared to conventional ventilation devices: if the ejector pin is removed from the mold by movement (essentially translation along the longitudinal axis of the shaft), contaminants, particularly unwanted filler or casting material, between the ejector pin and the mold, especially the bore, are carried away by the generally helical recess. Therefore, the hollow space undergoes a degree of self-cleaning. Attached Figure Description

[0057] Exemplary embodiments of the present invention will now be described in more detail with reference to the accompanying drawings, wherein... Figure 1 A push rod is shown according to one embodiment; Figure 2 A push rod is shown according to one embodiment; Figure 3 A push rod is shown according to one embodiment; Figure 4 A push rod is shown according to one embodiment; Figure 5 A push rod is shown according to one embodiment; Figure 6 A push rod is shown according to one embodiment; Figure 7 illustrates a top rod according to one embodiment; Figure 8 shows the shaft of the push rod according to one embodiment; and Figure 9 A top rod is shown according to one embodiment. Detailed Implementation

[0058] In the following description of exemplary embodiments, the same or similar components may have the same or corresponding reference numerals.

[0059] In particular, "may" or "can" indicates optional or preferred features of the invention. Therefore, in each case, the invention has an exemplary embodiment or disclosure having one or more corresponding features. This exemplary embodiment or disclosure can be combined, varied, or substituted in any desired manner with other exemplary embodiments or disclosures described above or below.

[0060] Figure 1This diagram shows an exemplary embodiment of an ejector pin 100 for ejecting a molded part from a casting tool. The ejector pin 100 includes a head 102 and a shaft 104. Both the head 102 and the shaft 104 are generally cylindrical. In another exemplary embodiment, the head 102 is integrally formed on the shaft 104.

[0061] Shaft 104 includes a longitudinal axis 106. In this exemplary embodiment, the longitudinal axis 106 is the axis of symmetry of the generally cylindrical shaft 104.

[0062] Shaft 104 includes two planar ends. These two planar ends are arranged perpendicular to the longitudinal axis 106 of the shaft. A first end is adjacent to or defined by a head 102. The other (second) end is a free end. In another exemplary embodiment, this free end may correspond to a molded part. In another exemplary embodiment, this free end may substantially correspond to the shape of a molded part.

[0063] Shaft 104 also includes a segment 108. Segment 108 extends from a free end in a direction along the head side (first) end of the shaft. In this exemplary embodiment, segment 108 is generally cylindrical. In another exemplary embodiment, segment 108 may include a section or segment of a cylinder. Segment 108 is a continuous segment of shaft 104.

[0064] The shaft 104 also has a plurality of recesses 110. The plurality of recesses 110 extend about the longitudinal axis of the shaft in a generally helical manner. In this exemplary embodiment, the plurality of recesses 110 includes five generally helical recesses. The plurality of recesses 110 have the same tilt angle. This results in the plurality of recesses 110 not intersecting, but extending in parallel.

[0065] Furthermore, in the example shown, multiple recesses 110 are evenly spaced within the segment 108: relative to the circumference of the shaft, they are arranged at the same angular distance from each other (each occupying one-fifth of the total circumference, i.e., 360° / 5 = 72°). Relative to the longitudinal axis of the shaft, they are arranged at the same pitch height difference from each other (each offset by one-fifth of the pitch height of each helix).

[0066] Figure 2 Another view showing an exemplary embodiment of the top rod 100.

[0067] Figure 3 A view showing another exemplary embodiment of an ejector pin 300 for ejecting a molded part from a casting tool is shown. The ejector pin 300 includes a head 302 and a shaft 304 having a longitudinal axis 306, wherein the shaft has a plurality of recesses 310 at least along a portion 308 that extend in a generally helical manner around the longitudinal axis.

[0068] In this exemplary embodiment, the plurality of recesses 310 are or include a plurality of first recesses 310.2 and a plurality of second recesses 310.4. The plurality of first recesses 310.2 are two generally helical recesses. The plurality of second recesses 310.4 are three generally helical recesses. The recesses in the plurality of first recesses 310.2 have a first angle of inclination, i.e., they extend parallel to each other. The recesses in the plurality of second recesses 310.4 have a second angle of inclination, i.e., they extend parallel to each other.

[0069] In this exemplary embodiment, the first tilt angle and the second tilt angle are different, causing the spirals of the plurality of first recesses 310.2 and the spirals of the plurality of second recesses 310.4 to intersect.

[0070] The recesses in the plurality of first recesses 310.2 are not arranged at uniform intervals (but are offset along the circumference at different angular distances or along the axis at different pitch heights). The recesses in the plurality of second recesses 310.4 are arranged at uniform intervals (i.e., offset along the circumference at the same angular distance of one-third of a circle, respectively).

[0071] Figure 4 A view showing another exemplary embodiment of an ejector pin 400 for ejecting a molded part from a casting tool is shown. The ejector pin 400 includes a head 402 and a shaft 404 having a longitudinal axis 406, wherein the shaft has a plurality of recesses 410 at least along a portion 408 that extend in a generally helical manner around the longitudinal axis.

[0072] In this exemplary embodiment, the plurality of recesses 410 are a plurality of first 410.2 and a plurality of second 410.4.

[0073] The plurality of first recesses 410.2 are three generally spiral recesses. The recesses in the plurality of first recesses 410.2 have a first tilt angle. The recesses in the plurality of first recesses 410.2 are evenly spaced from each other (that is, offset along the circumference at the same angular distance or along the axis at the same pitch height).

[0074] The plurality of second recesses 410.4 are three generally spiral recesses. The recesses in the plurality of second recesses 410.4 have a second inclination angle. The recesses in the plurality of second recesses 410.4 are evenly spaced from each other (that is, offset along the circumference by the same angular distance or along the axis by the same pitch height).

[0075] according to Figure 4 An exemplary embodiment of the push rod 400 and according to Figure 3 The exemplary implementation of the push rod 300 differs in that it has different recesses, in particular multiple first recesses that are evenly spaced apart.

[0076] At the end of segment 408, which substantially corresponds to the free end of shaft 406, one of the plurality of first recesses 410.2 and one of the plurality of second recesses 410.4 are respectively arranged or positioned opposite to each other. This arrangement or positioning opposite to each other should be understood as the first recess 410.2 and one of the second recesses 410.4 being displaced or rotated by 180° relative to the longitudinal axis 706 of the shaft, which serves as the axis of rotation. Furthermore, at the end of segment 408, the plurality of first recesses 410.2 and the plurality of second recesses 410.4 are uniformly arranged on or along segment 408. In other words, at the end of segment 408, the plurality of first recesses 410.2 and the plurality of second recesses 410.4 are uniformly arranged or distributed along the circumference or cross-section of the shaft. Therefore, uniform ventilation can be achieved across the cross-section of the shaft.

[0077] Figure 5 A cross-sectional view showing an exemplary embodiment of shaft 504 with magnified details. Shaft 504 is one of the exemplary embodiments described above. Figure 5 The cross-sectional view shown in the figure illustrates a cross-section of the generally cylindrical shaft 504 perpendicular to its longitudinal axis. In other words, this cross-sectional view shows a cross-section of the shaft 504 perpendicular to its longitudinal axis. Therefore, the shaft 504 is represented as a generally circular cross-section.

[0078] Figure 5 The diagram on the left also shows details of the circumference of shaft 504. This shaft includes a recess 510. Recess 510 may be one of a plurality of recesses as described in the aforementioned exemplary embodiments.

[0079] The recess 510 includes a recess 516 formed from the original shape of the shaft without a recess. In this exemplary embodiment, the recess 510 is generally concave. The concave shape is essentially an arcuate shape 512, wherein the arcuate shape includes a radius R.

[0080] Figure 6 A cross-sectional view of another exemplary embodiment of shaft 604 is shown. Shaft 604 may be the shaft in the exemplary embodiment described above. Shaft 604 is generally cylindrical. Figure 6 The cross-sectional view in the figure shows a cross section of the generally cylindrical shaft 604 perpendicular to its longitudinal axis. In other words, the cross-sectional view shows the cross section of shaft 604 perpendicular to its longitudinal axis.

[0081] Figure 6 Details of shaft 604 are also shown. This shaft includes a recess 610. In this exemplary embodiment, the recess 610 is generally planar or straight 614. The recess 610 includes a recess 616 formed from the original shape of the shaft without a recess.

[0082] The main difference between shaft 600 and shaft 500 lies in the construction of the recess. Shaft 500 includes a generally concave recess. Shaft 600 includes a generally planar or straight recess.

[0083] Figure 7 shows a view of another exemplary embodiment of an ejector pin 700 for ejecting a molded part from a casting tool. The ejector pin 700 includes a head 702 and a shaft 704 having a longitudinal axis 706. The shaft 704 includes two planar ends. These two planar ends are arranged perpendicular to the longitudinal axis 706. A first end is adjacent to or defined by the head 702. The other end (the second end) is a free end. In another exemplary embodiment, the free end may correspond to the molded part. In another exemplary embodiment, the free end may substantially correspond to the shape of the molded part. In one exemplary embodiment, the head 702, shaft 704, and longitudinal axis 706 are the head, shaft, and longitudinal axis described in the above exemplary embodiments.

[0084] Shaft 704 also includes a first segment 708a and a second segment 708b. The second segment 708b extends from the free end along the head side (first) end of the shaft. The first segment 708a and the second segment 708b are spaced apart from each other.

[0085] The shaft 704 has a plurality of recesses 710a at least along a first segment 708a, which extend in a generally helical manner about the longitudinal axis 706 of the shaft. In this exemplary embodiment, the plurality of recesses 710a are a plurality of first recesses 710a.2 and a plurality of second recesses 710a.4. For example, the plurality of recesses 710a correspond to the plurality of recesses in the above exemplary embodiment, in particular Figure 4 The plurality of recesses 410 shown.

[0086] The shaft 704 has a plurality of recesses 710b at least along the second segment 708b, which extend in a generally helical manner about the longitudinal axis 706 of the shaft. In this exemplary embodiment, the plurality of recesses 710b are a plurality of first recesses 710b.2 and a plurality of second recesses 710b.4. The plurality of recesses 710b correspond to the plurality of recesses in the above exemplary embodiment, in particular Figure 4 The plurality of recesses 410 shown.

[0087] Shaft 704 also includes a groove 718. Groove 718 is located within the interval between the first segment 708a and the second segment 708b. In other words, one end of the first segment 708a and one end of the second segment 708b adjoin the groove. Furthermore, one end of a plurality of recesses 710b and one end of a plurality of recesses 710a adjoin the groove 718. In the example shown, viewed from the head of the shaft, the groove 718 is positioned approximately 75% of the total length along the shaft's axis. Typically, the groove is preferably in the range of 60% to 75% of the shaft length. This allows the shaft to be shortened to a certain extent, resulting in a shortened shaft also having the groove.

[0088] The groove 718 extends substantially in a plane perpendicular to the longitudinal axis 706 of the shaft and extends in a straight line along the circumference of the shaft 706.

[0089] In this exemplary embodiment, the number of the plurality of first recesses 710b.2 and the number of the plurality of first recesses 710a.2 are the same. Furthermore, the tilt angles of the plurality of spiral first recesses 710b.2 and the spiral first recesses 710a.2 are the same.

[0090] Furthermore, the plurality of recesses 710a and 710b are arranged relative to each other such that, except for the interval between the first segment 708a and the second segment 708b, the plurality of recesses 710a and 710b are continuous. Simply put, the plurality of recesses 710b are continuations of the plurality of recesses 710a, and vice versa, wherein the continuation is interrupted by the interval between the first segment 708a and the second segment 708b.

[0091] Figure 8 shows a partial view of shaft 804 of another exemplary embodiment of an ejector pin used to eject a molded part from a casting tool. In this respect, shaft 804 corresponds to shaft 704 shown in Figure 7.

[0092] Shaft 804 includes a first segment 808a, a second segment 808b, and a groove 818. The first segment 808a and the second segment 808b are spaced apart from each other. The groove 818 is arranged between the first segment 808a and the second segment 808b. The groove 818 extends between the first segment 808a and the second segment 808b.

[0093] Furthermore, shaft 804 has a recess 810a at least along a first segment 808a and a recess 810b at least along a second segment 808b. The first segment 808a may correspond to a segment of the exemplary embodiment described above, and / or the second segment 808b may correspond to a segment of the exemplary embodiment described above.

[0094] Furthermore, Figure 8 shows, in dashed lines, the (imaginary) continuation 824 of the recess 810a and the (imaginary) continuation 824 of the recess 810b within the interval between the first segment 808a and the second segment 808b. The imaginary continuation 824 of the recess 810a is its stable continuation and has the same parameters as the recess 810a. The imaginary continuation 824 of the recess 810b is its stable continuation and has the same parameters as the recess 810b. In an exemplary embodiment, both the recesses 810a and 810b are helical, and the corresponding parameters include at least one of pitch height, tilt angle, pitch angle, displacement, and tilt degree. In this exemplary embodiment, the various parameters of the recesses 810a and 810b are identical.

[0095] Recesses 810a and 810b are arranged such that they merge with each other except for the spacing between the first segment 808a and the second segment 808b. Therefore, the dashed line continuation 824 is substantially consistent.

[0096] The groove 818 includes a recess 822 formed from the original shape of the shaft 826 without the groove 818. In this exemplary embodiment, the recess 822 is generally concave. The concave shape is a generally arcuate shape 820, wherein the arcuate shape has a radius R1. In one exemplary embodiment, the groove corresponds to the groove 718 in the exemplary embodiment shown in FIG. 7.

[0097] Figure 9 A view showing another exemplary embodiment of an ejector pin 900 for ejecting a molded part from a casting tool is shown. The ejector pin 900 includes a head 902 and a shaft 904 having a longitudinal axis 906. The shaft 904 includes two planar ends. These two planar ends are arranged perpendicular to the longitudinal axis 906. A first end is adjacent to or defined by the head 902. The other end (second end) is a free end. In another exemplary embodiment, the free end may correspond to the molded part. In another exemplary embodiment, the free end may substantially correspond to the shape of the molded part.

[0098] Shaft 904 includes a first shaft segment 928.2, a second shaft segment 928.4, and a third shaft segment 928.6. One end of the first shaft segment 928.2 is connected to the first end of the shaft, and the other end is connected to one end of the second shaft segment 928.4. The other end of the second shaft segment 928.4 is connected to one end of the third shaft segment 928.6. The other end of the third shaft segment 928.6 is connected to the free end of the shaft. Simply put, the first shaft segment 928.2, the second shaft segment 928.4, and the third shaft segment 928.6 separate shaft 904 along the longitudinal axis 906.

[0099] The first shaft segment 928.2 has a generally cylindrical shape and a diameter D2. The second shaft segment 928.4 has a generally truncated conical shape or a conical shape and an opening angle α. The third shaft segment 928.6 has a generally cylindrical shape and a diameter D4. The second shaft segment 928.4 is also designed to create a stable or continuous transition between the first and third shaft segments.

[0100] In the exemplary embodiment of the push rod 900 shown, the diameter D1 is approximately 10 mm and the diameter D4 is approximately 6 mm.

[0101] The third shaft segment 928.6 has a plurality of recesses 310 at least along the partial segment 908, which extend in a generally helical manner around the longitudinal axis 906 of the shaft. In the exemplary embodiment described above, the plurality of recesses 310 may be a plurality of recesses.

Claims

1. An ejector pin for ejecting a molded part from a casting tool, the ejector pin comprising a shaft having a longitudinal axis, wherein... The shaft has at least one or more recesses along a portion of its length. Its features are, The one or more recesses extend in a generally spiral manner around the longitudinal axis of the shaft.

2. The top rod according to claim 1, wherein the one or more recesses have at least one tilt angle.

3. The top rod according to claim 1 or 2, wherein the one or more recesses are generally concave in shape with respect to a cross section perpendicular to the longitudinal axis of the shaft.

4. The top rod according to claim 3, wherein the concave shape is approximately an arc shape.

5. The top rod according to claim 4, wherein the arcuate shape has a radius, and the ratio of the radius to the radius of the shaft is between 4 and 26.

6. The top rod according to claim 1 or 2, wherein the one or more recesses are substantially planar with respect to a cross section perpendicular to the longitudinal axis of the shaft.

7. The top rod according to any one of claims 1 to 6, wherein the one or more recesses represent recesses formed from the original shape of the shaft without recesses, at a radius between 0.3% and 1.0% of the shaft.

8. The top rod according to any one of claims 1 to 7, wherein the one or more recesses are a plurality of recesses.

9. The top rod according to claim 8, wherein the plurality of recesses is an odd number.

10. The top rod according to claim 8 or 9, wherein the plurality of recesses have the same tilt angle.

11. The push rod according to claim 8 or 9, wherein At least one of the plurality of recesses has a first recess having a first tilt angle; and At least one of the plurality of recesses has a second recess having a second tilt angle.

12. The push rod according to any one of claims 1 to 11, further comprising a low-friction coating on the said section, particularly with a friction value between 0.1 and 0.

15.

13. The top rod of claim 12, wherein the low-friction coating comprises an amorphous carbon layer.

14. The top rod according to any one of claims 1 to 13, wherein the shaft is generally cylindrical, particularly having a diameter between 1 mm and 20 mm.

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