Small space split undercut shrink mechanism for precision plastic molds

Abstract

The present invention discloses a small space split undercut shrinking mechanism for a precision plastic mold, which includes a central shovel base, three peripheral shovel bases, three first oblique wedge-type sliders and three second oblique wedge-type sliders. The first oblique wedge-type sliders and the second oblique wedge-type sliders are staggered and spaced around the circumference of the central shovel base. The inner side surface of the first oblique wedge-type slider and the outer side surface of the central shovel base are provided with a sliding engagement structure, and the movement of the central shovel base synchronously drives the three first oblique wedge-type sliders to shrink or expand. The peripheral shovel base and the second oblique wedge-type slider are matched in sliding transmission, and the movement of the peripheral shovel base synchronously drives the second oblique wedge-type slider to shrink or expand. In this way, by designing the shrinking mechanism in a split manner, the central shovel base can be made smaller, so that the undercut insert enclosed by the oblique wedge-type sliders can be made smaller, thereby meeting the demolding requirements of small-sized annular undercuts in a small space.

Description

Technical Field

[0001] The invention relates to the technical field of injection molds, and in particular to a small-space split-type undercut shrinkage mechanism for a precision plastic mold. Background Art

[0002] In the injection mold industry, we often encounter products with special structural characteristics. Figure 1 The annular plastic product shown in the figure has an annular undercut on the inner ring at one end and an M14X1.25 internal thread on the other end. The inner hole diameter of the plastic product is 14.1mm, which is larger than the internal thread, so it cannot be demolded together with the internal thread core. Therefore, for the above-mentioned plastic products, it is usually demolded from one end of the annular undercut. As for the annular undercut, the petal-type shrinking core-pulling structure, also known as the shrinking mechanism, is currently commonly used. The existing standard shrinking mechanism mainly includes a central shovel base and a plurality of inclined wedge-type sliders connected to the central shovel base. When demolding, the central shovel base is pulled out from the center of the plurality of inclined wedge-type sliders, and at the same time drives the inclined wedge-type sliders to move closer to the center, so that the slider is detached from the undercut and then ejects the product. However, the above-mentioned plastic products need to have both undercuts and small-diameter cores, and the existing standard shrinking mechanism can no longer meet this requirement. Summary of the invention

[0003] In view of the problems existing in the prior art, the main purpose of the present invention is to provide a small-space split undercut shrinking mechanism for a precision plastic mold to meet the demoulding requirements of such a small-sized annular undercut.

[0004] To achieve the above-mentioned purpose, the small space split undercut shrinkage mechanism of the precision plastic mold proposed by the present invention comprises a central shovel base, three peripheral shovel bases, three first oblique wedge sliders and three second oblique wedge sliders, wherein the first oblique wedge sliders and the second oblique wedge sliders are staggered and spaced around the peripheral side of the central shovel base;

[0005] The inner side surface of the first inclined wedge-type slider and the outer side surface of the central shovel base are provided with a sliding engagement structure, and when the central shovel base moves along its axial direction, it can synchronously drive the first inclined wedge-type slider to contract toward the center of the central shovel base or expand outward from the center of the central shovel base;

[0006] The second inclined wedge-type slider has a transverse sliding portion, and the transverse sliding portion has a guide hole which is at a certain angle to the axial direction of the central shovel base; the peripheral shovel base is inserted into the guide hole of the second inclined wedge-type slider, and has an inner guide surface and an outer guide surface which are at a certain angle to the axial direction of the central shovel base. When the peripheral shovel base moves along the axial direction of the central shovel base, it synchronously drives the second inclined wedge-type slider to contract toward the center of the central shovel base or expand outward from the center of the central shovel base.

[0007] In the above embodiment, the lower end of the first inclined wedge-type slider has an extension portion, and when the mold is closed, the extension portion of the first inclined wedge-type slider encloses a core that matches the shape of the inner hole of the product.

[0008] Optionally, the sliding engagement structure comprises: a dovetail groove arranged on the outer peripheral side of the center shovel base and a slide rail arranged on the inner side surface of the first inclined wedge-type sliding block and slidingly engaged with the dovetail groove.

[0009] Optionally, the peripheral shovel base is parallel to the axial direction of the central shovel base, and its outer guide surface is arranged on the outer side surface of the peripheral shovel base, and its inner guide surface is arranged on the inner side surface of the peripheral shovel base and is located below the outer guide surface.

[0010] Optionally, it also includes an upper slide seat, on which the upper end of the first inclined wedge-type sliding block is slidably disposed; the upper end of the peripheral shovel base is fixed to the upper slide seat, and the lower end thereof passes through the upper slide seat and is inserted into its corresponding guide hole.

[0011] Optionally, a cover plate is provided on the upper slide seat, and the cover plate covers the upper end surfaces of the first inclined wedge-type sliding block and the peripheral shovel base.

[0012] Optionally, a lower sliding seat is further included, the lower sliding seat is located below the upper sliding seat, and the transverse sliding portion of the second inclined wedge-type sliding block is slidably arranged on the lower sliding seat, and the lower end thereof passes through the lower sliding seat.

[0013] Optionally, a slide groove corresponding to the second inclined wedge-type slider is provided in the lower sliding seat, and the transverse sliding portion of the second inclined wedge-type slider is slidably disposed in the corresponding slide groove.

[0014] Optionally, side strips are provided on both sides of the transverse sliding portion, and two pressing blocks are provided in the sliding groove. The pressing blocks are respectively arranged on both sides of the transverse sliding portion and pressed against the upper side surfaces of the side strips.

[0015] The technical solution of the present invention drives the demolding of the inclined wedge-type slider by adopting a central shovel base and three peripheral shovel bases. When opening the mold, the central shovel base first pulls out the core and drives the three first inclined wedge-type sliders to detach from the product undercut, and then the peripheral shovel base and the central shovel base move together to drive the three second inclined wedge-type sliders to detach from the product undercut, so that all the inclined wedge-type sliders detach from the product undercut, thereby realizing the demolding of the annular undercut.

[0016] The present invention adopts a split design for the shrinking mechanism, in which the central shovel base only needs to cooperate with the first inclined wedge-type slider, and the second inclined wedge-type slider is driven by the peripheral shovel base. Therefore, the central shovel base can be made smaller, so that the undercut core enclosed by the inclined wedge-type slider can be made smaller, thereby meeting the demoulding requirements of small-sized annular undercuts in a small space. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1It is a cross-sectional view of a conventional annular plastic product with an annular undercut;

[0018] Figure 2 It is an exploded schematic diagram of an embodiment of the present invention;

[0019] Figure 3 The schematic diagram of the structure of the central shovel foundation is shown in FIG.

[0020] Figure 4 is a schematic structural diagram of a first inclined wedge-type slider;

[0021] Figure 5 is a schematic diagram of the structure of the second inclined wedge-type slider;

[0022] Figure 6 It is a cross-sectional view of an embodiment of the present invention in a mold closing state;

[0023] Figure 7 It is a cross-sectional view of an embodiment of the present invention in a state of one demoulding;

[0024] Figure 8 It is a cross-sectional view of an embodiment of the present invention in a secondary demoulding state;

[0025] Fig. 9 for Figure 7 A local enlarged schematic diagram of the middle A;

[0026] Fig.10 for Figure 8 A local enlarged schematic diagram of point B in the middle.

[0027] In the attached figure numbers: 100-central shovel base, 101-dovetail groove; 200-peripheral shovel base, 200a-outer guide surface, 200b-inner vertical surface, 200c-inner guide surface; 300-first inclined wedge-type slider, 301-slide rail, 302-undercut core, 303-extension portion; 400-second inclined wedge-type slider, 401-lateral sliding portion, 402-guide hole, 402a-outer side surface, 402b-inner side surface, 403-undercut core, 404 side strip; 500-upper slide seat, 510-cover plate; 600-lower slide seat, 601-slide groove, 610-pressing block; 700-product, 701-annular undercut, 702-internal thread, 703-inner hole. DETAILED DESCRIPTION

[0028] The following will be combined with the accompanying drawings in the embodiments of the present invention to provide a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Please refer to the instruction manual Figure 2-10 In an embodiment of the present invention, a small space split undercut shrinkage mechanism for a precision plastic mold is proposed. The small space split undercut shrinkage mechanism for a precision plastic mold includes a central shovel base 100, three peripheral shovel bases 200, three first inclined wedge sliders 300 and three second inclined wedge sliders 400. The first inclined wedge sliders 300 and the second inclined wedge sliders 400 are staggered and spaced around the circumference of the central shovel base 100.

[0030] The inner side surface of the first inclined wedge slider 300 and the outer side surface of the central shovel base 100 are provided with a sliding engagement structure. When the central shovel base 100 moves along its axial direction, the first inclined wedge slider 300 can be synchronously driven to shrink toward the center of the central shovel base 100 or expand outward from the center of the central shovel base 100. The second inclined wedge slider 400 has a transverse sliding portion 401, and the transverse sliding portion 401 has a guide hole 402 that is at a certain angle to the axial direction of the central shovel base 100. The peripheral shovel base 200 is inserted into the guide hole 402 of the second inclined wedge slider 400, and has an inner guide surface 200c and an outer guide surface 200a that are at a certain angle to the axial direction of the central shovel base 100. When the peripheral shovel base 200 moves along the axial direction of the central shovel base 100, the second inclined wedge slider 400 is synchronously driven to shrink toward the center of the central shovel base 100 or expand outward from the center of the central shovel base 100.

[0031] The outer side surfaces of the lower ends of the first inclined wedge slider 300 and the second inclined wedge slider 400 are respectively provided with undercut cores 302 and 403 which match the annular undercut 701 of the product 700. In the mold closing state, the first inclined wedge slider 300 and the second inclined wedge slider 400 are staggered and fitted on the outer peripheral side of the center shovel base 100, and the undercut cores 302 of the first inclined wedge slider 300 and the undercut cores 403 of the second inclined wedge slider 400 surround an annular undercut core which matches the annular undercut 701 of the product 700.

[0032] The demoulding work of the split undercut shrinkage mechanism provided by the present invention is divided into:

[0033] One-time demoulding: the central shovel base 100 is first pulled out for a distance, and at the same time drives the first inclined wedge-type slider 300 to move along the movement direction of the central shovel base 100, and shrinks toward the axis of the central shovel base 100, so that the undercut core 302 of the first inclined wedge-type slider 300 is separated from the annular undercut 701 of the product 700.

[0034] Secondary demolding; the peripheral shovel base 200 and the central shovel base 100 move together. During the axial movement of the peripheral shovel base 200 along the central shovel base 100, the inner guide surface 200c of the peripheral shovel base 200 contacts the inner surface 402b of the guide hole 402, thereby driving the second inclined wedge-type slider 400 to move along the movement direction of the central shovel base 100 and shrink toward the axis of the central shovel base 100, so that the undercut core 403 of the second inclined wedge-type slider 400 is separated from the annular undercut 701 of the product 700, thereby realizing the demolding of the annular undercut 701 of the product 700.

[0035] The mold closing process is opposite to the above-mentioned demolding process. The peripheral shovel base 200 is reset first. During the reset process, the outer guide surface 200a of the peripheral shovel base 200 contacts the outer surface 402a of the guide hole 402, driving the second inclined wedge-type slider 400 to reset; then, the central shovel base 100 is reset and drives the first inclined wedge-type slider 300 to reset.

[0036] The present invention adopts a split design for the shrinking mechanism. The central shovel base 100 only needs to cooperate with the first inclined wedge-type slider 300, and the second inclined wedge-type slider 400 is driven by the peripheral shovel base 200. Therefore, the central shovel base 100 can be made smaller, so that the annular undercut core enclosed by the inclined wedge-type slider can be made smaller, thereby meeting the demolding requirements of the small-sized annular undercut 701 in a small space.

[0037] In this embodiment, the lower end of the first wedge-shaped slider 300 has an extension portion 303. In the mold closing state, the extension portion 303 of the first wedge-shaped slider 300 encloses a core that matches the shape of the inner hole of the product 700. Figure 1 The plastic product 700 shown also has an inner hole 703 in the annular undercut 701, and the diameter of the inner hole 703 is larger than the size of the internal thread 702. Therefore, an extension portion 700 is provided at the lower end of the first inclined wedge-type slider 300, and the first inclined wedge-type slider 300 is used to enclose a core of the inner hole 703, so that the inner hole 700 is formed in the product 700 while the annular undercut 701 is formed. During demoulding, the core can also move with the first inclined wedge-type slider 300 to separate from the inner hole 703 of the product 700.

[0038] Optionally, in the above embodiment, the sliding engagement structure between the first inclined wedge slider 300 and the central shovel base 100 is: a dovetail groove 101 provided on the outer peripheral side of the central shovel base 100 and a slide rail 301 provided on the inner side of the first inclined wedge slider 300 and slidably engaged in the dovetail groove 101. The central shovel base 100 is conical, and when the central shovel base 100 is pulled out from the center of the three first inclined wedge sliders 300, the slide rail 301 pulls the first inclined wedge slider 300 to move upward relatively and close to the center of the central shovel base 100, thereby making the undercut insert 302 of the first inclined wedge slider 300 detach from the annular undercut 701 of the product 700. By using the dovetail groove 101 and the corresponding slide rail 301 as the sliding engagement structure, the matching accuracy is high and stable.

[0039] Optionally, in the above embodiment, the main body of the peripheral shovel base 200 is parallel to the axial direction of the central shovel base 100, and its outer guide surface 200a is arranged on the outer side of the peripheral shovel base 200, and its inner guide surface 200c is arranged on the inner side of the peripheral shovel base 200 and is located below the outer guide surface 200a. Figure 6 As shown, in the mold closing state, the outer guide surface 200a of the peripheral shovel base 200 is in contact with the outer side surface 402a of the guide hole 402, so that the second inclined wedge slider 400 remains in an expanded state. When the peripheral shovel base 200 moves upward, the upper edge of the inner side surface 402a of the guide hole 402 contacts the inner vertical surface 200b of the peripheral shovel base 200, until the inner guide surface 200c of the peripheral shovel base 200 is in contact with the inner side surface 402b of the guide hole 402, the movement of the peripheral shovel base 200 can drive the second inclined wedge slider 400 to move and shrink toward the axis of the central shovel base 100. In this way, the demolding time of the second inclined wedge slider 400 can be delayed, so that the first inclined wedge slider 300 is demolded for a certain distance first, and then a sufficient virtual space is formed for the demolding of the second inclined wedge slider 400.

[0040] Optionally, in the above embodiment, the split undercut shrinkage mechanism further includes an upper slide 500. The upper end of the first inclined wedge-type slider 300 is slidably disposed on the upper slide 500. The upper end of the peripheral shovel base 200 is fixed to the upper slide 500, and the lower end thereof passes through the upper slide 500 and is inserted into the corresponding guide hole 402. By providing the upper slide 500, the first inclined wedge-type slider 300 and the peripheral shovel base 200 can be driven to move simultaneously by the upper slide 500, thereby simplifying the structure of the shrinkage mechanism and improving the demoulding efficiency.

[0041] Optionally, in the above embodiment, a cover plate 510 is provided on the upper slide 500, and the cover plate 510 covers the upper side surface of the upper slide 500, and presses the first inclined wedge-type slider 300 and the peripheral shovel base 200 onto the upper slide 500. In this way, the first inclined wedge-type slider 300 and the peripheral shovel base 200 can be relatively fixed on the upper slide 500 through the cover plate 510, which facilitates the assembly of the retracting mechanism.

[0042] Optionally, in the above embodiment, the split undercut shrink mechanism further includes a lower slide seat 600, which is located below the upper slide seat 500. The lateral sliding portion 401 of the second inclined wedge-type slider 400 is slidably disposed on the lower slide seat 600, and its lower end passes through the lower slide seat 600. At the same time, the lower slide seat 600 is provided with a avoidance hole for avoiding the peripheral shovel base 200. In the mold closing state, the peripheral shovel base 200 passes through its corresponding guide hole 402 and avoidance hole in sequence. The lower slide seat 600 is provided to facilitate the installation of the second inclined wedge-type slider 400.

[0043] Optionally, in the above embodiment, a slide groove 601 corresponding to the second inclined wedge-type slider 400 is provided in the lower slide seat 600, and the transverse sliding portion 401 of the second inclined wedge-type slider 400 is slidably disposed in its corresponding slide groove 601. In this way, the second inclined wedge-type slider 400 can slide along the inner wall of the slide groove 601 to maintain the stability of the second inclined wedge-type slider 400 during the sliding process.

[0044] Furthermore, in the above embodiment, side strips 404 are provided on both sides of the transverse sliding portion 401, and two pressing blocks 610 are provided in the slide groove 601. The pressing blocks 610 are provided on both sides of the transverse sliding portion 401 and are pressed against the upper side of the side strips 404. By providing the side strips 404 on both sides of the transverse sliding portion 401 and the pressing blocks 610, the second inclined wedge-type slider 400 is restricted to slide between the two pressing blocks 610, thereby further improving the stability of the second inclined wedge-type slider 400 and facilitating the installation and removal of the second inclined wedge-type slider 400.

[0045] The above description is only a preferred embodiment of the present invention and is not intended to be construed as limiting the present invention. Any minor modifications, equivalent substitutions and improvements made to the above embodiments based on the technical essence of the present invention should be included in the protection scope of the technical solution of the present invention.

Claims

1. A small space split undercut shrinkage mechanism for precision plastic molds, characterized in that: It comprises a central shovel base, three peripheral shovel bases, three first oblique wedge-type sliders and three second oblique wedge-type sliders, wherein the first oblique wedge-type sliders and the second oblique wedge-type sliders are alternately spaced and surround the peripheral side of the central shovel base; The inner side surface of the first inclined wedge-type slider and the outer side surface of the central shovel base are provided with a sliding engagement structure, and when the central shovel base moves along its axial direction, it can synchronously drive the first inclined wedge-type slider to contract toward the center of the central shovel base or expand outward from the center of the central shovel base; The second inclined wedge-type slider has a transverse sliding portion, and the transverse sliding portion has a guide hole that is at a certain angle to the axial direction of the central shovel base; the peripheral shovel base is inserted into the guide hole of the second inclined wedge-type slider, and has an inner guide surface and an outer guide surface that are at a certain angle to the axial direction of the central shovel base. When the peripheral shovel base moves along the axial direction of the central shovel base, it synchronously drives the second inclined wedge-type slider to contract toward the center of the central shovel base or expand outward from the center of the central shovel base; The sliding engagement structure comprises: a dovetail groove arranged on the outer peripheral side of the central shovel base and a slide rail arranged on the inner side of the first inclined wedge-type sliding block and slidingly engaged with the dovetail groove; The peripheral shovel base is parallel to the axial direction of the central shovel base, and its outer guide surface is arranged on the outer side surface of the peripheral shovel base, and its inner guide surface is arranged on the inner side surface of the peripheral shovel base and is located below the outer guide surface.

2. The small space split undercut shrinkage mechanism for precision plastic mold according to claim 1, characterized in that: It also includes an upper slide seat, on which the upper end of the first inclined wedge-type sliding block is slidably disposed; the upper end of the peripheral shovel base is fixed to the upper slide seat, and the lower end thereof passes through the upper slide seat and is inserted into its corresponding guide hole.

3. The small space split undercut shrinkage mechanism for precision plastic mold according to claim 2, characterized in that: A cover plate is provided on the upper sliding seat, and the cover plate covers the upper end surfaces of the first inclined wedge-type sliding block and the peripheral shovel base.

4. The small space split undercut shrinkage mechanism for precision plastic mold according to claim 2, characterized in that: It also includes a lower sliding seat, which is located below the upper sliding seat. The transverse sliding portion of the second inclined wedge-type sliding block is slidably arranged on the lower sliding seat, and its lower end passes through the lower sliding seat.

5. The small space split undercut shrinkage mechanism for precision plastic molds as claimed in claim 4, characterized in that: The lower sliding seat is provided with a sliding groove corresponding to the second inclined wedge-type sliding block one by one, and the transverse sliding portion of the second inclined wedge-type sliding block is slidably arranged in its corresponding sliding groove.

6. The small space split undercut shrinkage mechanism for precision plastic mold according to claim 5, characterized in that: Side strips are arranged on both sides of the transverse sliding part, and two pressing blocks are arranged in the sliding groove. The pressing blocks are arranged on both sides of the transverse sliding part and pressed on the upper side of the side strips.

7. The small space split undercut shrinkage mechanism for a precision plastic mold according to any one of claims 1 to 6, characterized in that: The lower end of the first inclined wedge-type slider is provided with an extension portion. When the mold is closed, the extension portion of the first inclined wedge-type slider encloses a core that matches the shape of the inner hole of the product.

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