Fatigue-resistant precision thimble assembly

Abstract

The utility model discloses a kind of fatigue-resistant precision thimble assemblies, including buffer base, needle bar and needle head, the needle bar is threadedly connected with needle head, the needle bar tail is embedded in buffer base.In the utility model, the needle bar is connected with the needle head by thread, and the radial threaded hole is opened in the side surface of the needle bar, and the locking rod is locked by screw, the needle bar and the needle head can be further locked, when disassembling, first loosen the screw, then rotate the needle head, and the needle bar and the buffer base can be separated by pushing the push plate on both sides, so that the thimble split design is realized, maintenance is convenient, and the cost of wear and replacement is reduced, a transition arc is arranged at the connection between the needle bar and the needle head, the stress peak is reduced, the fatigue life is improved, the needle bar adopts stepped diameter design, the front end is slightly thin, the centring is ensured, and the outer wall of the needle bar is coated with PTFE coating, the friction is reduced, and the guiding accuracy is improved.

Description

Technical Field

[0001] This utility model relates to the field of machining or mold technology, specifically to a fatigue-resistant precision ejector pin assembly. Background Technology

[0002] Ejector pins are the core components in molds used to demold plastic products. They are usually composed of a metal rod and an ejector sleeve. They ensure molding quality through mechanical transmission and microscopic venting. Traditional ejector pins are prone to fatigue and breakage under repeated stress, resulting in a short lifespan.

[0003] The prior art, disclosed in patent publication number CN217768340U, presents the following technical solution: a practical ejector pin assembly, specifically relating to the manufacturing field of LED chip sorting machines, comprising an ejector pin and an ejector pin rod. The ejector pin is disposed within the ejector pin rod and an ejector pin nut. An ejector pin spring rod is fixedly connected to the ejector pin rod, and the ejector pin spring rod is elastically connected to the ejector pin via an elastic component. A protective ejector pin nut is sleeved on the outer side of the ejector pin, and the ejector pin nut is fitted onto the ejector pin rod. In use, the ejector pin rod is fixed to the ejector pin slide assembly and hidden inside the ejector pin cap assembly to ensure the stability of the ejector pin rod.

[0004] The above-mentioned technical solution uses a rigid fixing method for the ejector pin rod, which is prone to breakage due to stress concentration after long-term use. This requires disassembling the entire frame assembly, resulting in high replacement costs. In addition, the buffer relies on external elastic components, which affects the ejector pin reset accuracy and leads to material positioning deviation. Utility Model Content

[0005] The purpose of this invention is to provide a fatigue-resistant precision ejector pin assembly to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a fatigue-resistant precision ejector pin assembly, comprising a buffer base, a needle rod, and a needle head, wherein the needle rod is threadedly connected to the needle head, and the tail of the needle rod is embedded in the buffer base.

[0007] The outer surfaces of both the front and rear sides of the needle bar tail are provided with mounting grooves. A spring telescopic rod is provided in each mounting groove. An L-shaped snap-fit ​​plate is provided at one end of each spring telescopic rod. A push plate is fixedly connected to the upper outer surface of each L-shaped snap-fit ​​plate. The side walls of both sides of the buffer base are provided with slots. The L-shaped snap-fit ​​plate snaps into the slots. A limit groove is provided above the slot and on the inner side of the upper surface of the buffer base. The bottom of the push plate is slidably connected to the bottom side of the limit groove.

[0008] In the above technical solution, the needle bar is engaged in the slot inside the buffer base by an L-shaped snap-fit ​​plate, and the needle bar can be separated from the buffer base by pushing the push plates on both sides.

[0009] The needle bar has a threaded groove at the top and a locking groove at the bottom. The locking groove has a radial threaded hole in the transverse direction and a fitting groove at one end of the radial threaded hole. The fitting groove is located on the outer surface of the needle bar. The end of the needle tip near the needle bar is fixedly connected to a threaded section. The bottom of the threaded section is fixedly connected to a locking rod, and the locking rod has a through-hole.

[0010] In the above technical solution, the needle bar is connected to the needle head by a thread, and a radial threaded hole is opened on the side of the needle bar. The locking rod is locked by a screw, which can further lock the needle bar and the needle head, realize the split design of the ejector pin, facilitate maintenance, and reduce the cost of wear and replacement.

[0011] As a further preferred embodiment of this technical solution, the connection between the needle tip and the needle shaft is provided with a transition arc.

[0012] In the above technical solution, a transition arc is set at the connection between the needle bar and the needle tip to reduce stress peak and improve fatigue life.

[0013] As a further preferred embodiment of this technical solution, the guide section of the needle bar has a stepped diameter, with the front diameter being 0.05-0.1mm smaller than the rear diameter.

[0014] In the above technical solution, the needle bar adopts a stepped diameter design, with the front end being slightly thinner to ensure centering.

[0015] As a further preferred embodiment of this technical solution, the needle tip is made of cemented carbide, and the outer surface of the needle shaft is coated with a PTFE coating.

[0016] In the above technical solution, the outer wall of the needle bar is coated with a PTFE coating to reduce friction and improve guiding accuracy.

[0017] As a further preferred embodiment of this technical solution, the locking rod is disposed in the locking groove. When the threaded section is tightened in the threaded groove, the insertion hole is aligned with the radial threaded hole, and a screw is threadedly connected between the insertion hole and the radial threaded hole.

[0018] As a further preferred embodiment of this technical solution, an elastic buffer block is provided on the inner side of the buffer base, and the elastic buffer block is interference-fitted with the tail of the needle bar.

[0019] In the above technical solution, the elastic buffer block can buffer the impact force through elastic deformation when the ejector pin is subjected to force, reduce the rigid impact on the pin bar and frame, and reduce the wear of the ejector pin. Moreover, it can quickly recover after elastic deformation, ensuring the repeatability and positioning accuracy of the ejector pin.

[0020] As a further preferred embodiment of this technical solution, the buffer base is fixed to the mold plate by pressing.

[0021] This utility model provides a fatigue-resistant precision ejector pin assembly, which has the following beneficial effects:

[0022] (1) The needle bar of this utility model is connected to the needle head by a thread, and a radial threaded hole is opened on the side of the needle bar. The locking rod is locked by a screw, which can further lock the needle bar and the needle head. When disassembling, the screw is loosened first, and then the needle head is rotated to separate them, which is convenient to operate. In addition, the needle bar is locked in the slot on the inner side of the buffer base by an L-shaped locking plate. The needle bar can be separated from the buffer base by pushing the push plates on both sides, thereby realizing the split design of the ejector pin, which is convenient to maintain and reduces the cost of wear and replacement.

[0023] (2) The present invention sets a transition arc at the connection between the needle bar and the needle head to reduce stress peak and improve fatigue life. The needle bar adopts a stepped diameter design with a slightly thinner front end to ensure centering. The outer wall of the needle bar is coated with PTFE to reduce friction and improve guiding accuracy. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0025] Figure 2 This is a schematic diagram showing the disassembled structure of the buffer base, needle bar, and needle head of this utility model;

[0026] Figure 3 This is a schematic diagram of the structure of the top of the needle bar of this utility model;

[0027] Figure 4 This is a schematic diagram of the connection between the buffer base and the needle bar of this utility model;

[0028] Figure 5 This is a schematic diagram of the structure of the buffer base of this utility model;

[0029] In the diagram: 1. Buffer base; 11. Elastic buffer block; 12. Slot; 13. Limiting slot; 2. Needle bar; 21. Mounting slot; 22. Spring telescopic rod; 23. L-shaped snap-fit ​​plate; 24. Push plate; 25. Threaded groove; 26. Locking groove; 27. Radial threaded hole; 28. Fitting groove; 29. ​​Screw; 3. Needle tip; 31. Transition arc; 32. Threaded section; 33. Locking rod; 34. Insertion hole. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention.

[0031] This utility model provides a technical solution: such as Figure 1 and Figure 2As shown in this embodiment, a fatigue-resistant precision ejector pin assembly includes a buffer base 1, a pin shank 2, and a pin head 3. The buffer base 1 is fixed to the mold plate by pressing. A transition arc 31 is provided at the connection between the pin head 3 and the pin shank 2. The transition arc 31 at the connection between the pin shank 2 and the pin head 3 reduces stress peaks and improves fatigue life. The guide section of the pin shank 2 has a stepped diameter, with the front diameter being 0.05-0.1mm smaller than the rear diameter. The stepped diameter design of the pin shank 2, with a slightly thinner front end, ensures centering. The pin head 3 is made of [material missing]. The needle bar 2 is made of hard alloy and coated with PTFE on its outer surface and outer wall to reduce friction and improve guiding accuracy. The inner side of the buffer base 1 is provided with an elastic buffer block 11, which can be made of silicone. The elastic buffer block 11 is interference-fitted with the tail of the needle bar 2. When the ejector pin is subjected to force, the elastic buffer block 11 can buffer the impact force through elastic deformation, reduce the rigid impact on the needle bar 2 and the frame, and reduce the wear of the ejector pin. Moreover, it can quickly recover after elastic deformation to ensure the repeatability of the ejector pin.

[0032] like Figure 4 and Figure 5 As shown, the tail of the needle bar 2 is embedded in the buffer base 1. The outer surfaces of the front and rear sides of the tail of the needle bar 2 are provided with mounting grooves 21. Each mounting groove 21 is provided with a spring telescopic rod 22. One end of each spring telescopic rod 22 is provided with an L-shaped locking plate 23. The upper outer surface of each L-shaped locking plate 23 is fixedly connected with a push plate 24. Both sides of the buffer base 1 are provided with slots 12. The L-shaped locking plate 23 is engaged with the slots 12. Above the slots 12 and on the inner side of the upper surface of the buffer base 1, there are limit grooves 13. The bottom of the push plate 24 is slidably connected to the bottom side of the limit groove 13. The needle bar 2 is engaged in the slots 12 on the inner side of the buffer base 1 by the L-shaped locking plate 23. By pushing the push plates 24 on both sides, the needle bar 2 can be separated from the buffer base 1, thereby realizing the split design of the ejector pin, which is convenient for maintenance and reduces the cost of wear and replacement.

[0033] like Figure 2 and Figure 3As shown, the needle bar 2 is threadedly connected to the needle head 3. The top of the needle bar 2 has a threaded groove 25, and the bottom of the threaded groove 25 has a locking groove 26. The locking groove 26 has a radial threaded hole 27, and one end of the radial threaded hole 27 has a fitting groove 28 located on the outer surface of the needle bar 2. A threaded section 32 is fixedly connected to one end of the needle head 3 near the needle bar 2. A locking rod 33 is fixedly connected to the bottom of the threaded section 32. The locking rod 33 has a through-hole 34. The locking rod 33 is configured with… Within the locking groove 26, when the threaded section 32 is screwed into the threaded groove 25, the insertion hole 34 and the radial threaded hole 27 are aligned. A screw 29 is threadedly connected between the insertion hole 34 and the radial threaded hole 27. The needle rod 2 is connected to the needle head 3 by threads, and the radial threaded hole 27 is opened on the side of the needle rod 2. The locking rod 33 is locked by the screw 29, which can further lock the needle rod 2 and the needle head 3. When disassembling, first loosen the screw 29, and then rotate the needle head 3 to separate them, which is convenient for operation.

[0034] This utility model provides a fatigue-resistant precision ejector pin assembly. The specific working principle is as follows: When the worn needle bar 2 or needle head 3 needs to be replaced, the screw 29 is loosened with a tool to disengage it from the radial threaded hole 27. Then, the needle head 3 is rotated so that the threaded section 32 disengages from the threaded groove 25. Next, the push plates 24 on both sides are pushed to compress and deform the spring telescopic rod 22, thereby causing the L-shaped snap plate 23 to disengage from the snap groove 12, which allows the needle bar 2 to separate from the buffer base 1.

[0035] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A fatigue-resistant precision ejector pin assembly, comprising a buffer base (1), a pin bar (2), and a pin tip (3), characterized in that: The needle bar (2) is threadedly connected to the needle head (3), and the tail of the needle bar (2) is embedded in the buffer base (1); The needle bar (2) has mounting grooves (21) on both the front and rear outer surfaces. Each mounting groove (21) has a spring telescopic rod (22). Each spring telescopic rod (22) has an L-shaped snap-fit ​​plate (23) on one side. Each L-shaped snap-fit ​​plate (23) has a push plate (24) fixedly connected to the upper outer surface of the L-shaped snap-fit ​​plate (23). Each buffer base (1) has a snap-fit ​​groove (12) on both side walls. The L-shaped snap-fit ​​plate (23) snaps into the snap-fit ​​groove (12). Each snap-fit ​​groove (13) is opened above the snap-fit ​​groove (12) and on the inner side of the upper surface of the buffer base (1). The bottom of the push plate (24) is slidably connected to the bottom side of the limit groove (13). The needle bar (2) has a threaded groove (25) at the top and a locking groove (26) at the bottom. The locking groove (26) has a radial threaded hole (27) in the transverse direction. One end of the radial threaded hole (27) has a fitting groove (28) located on the outer surface of the needle bar (2). The end of the needle tip (3) near the needle bar (2) is fixedly connected to a threaded section (32). The bottom of the threaded section (32) is fixedly connected to a locking rod (33). The locking rod (33) has a through-hole (34).

2. The fatigue-resistant precision ejector assembly according to claim 1, characterized in that: The connection between the needle tip (3) and the needle bar (2) is provided with a transition arc (31).

3. The fatigue-resistant precision ejector assembly according to claim 1, characterized in that: The guide section of the needle bar (2) has a stepped diameter, with the front diameter being 0.05-0.1 mm smaller than the rear diameter.

4. The fatigue-resistant precision ejector assembly according to claim 1, characterized in that: The needle (3) is made of hard alloy, and the outer surface of the needle bar (2) is coated with PTFE.

5. The fatigue-resistant precision ejector assembly according to claim 1, characterized in that: The locking rod (33) is set in the locking groove (26). When the threaded section (32) is tightened in the threaded groove (25), the insertion hole (34) is aligned with the radial threaded hole (27). A screw (29) is threadedly connected between the insertion hole (34) and the radial threaded hole (27).

6. The fatigue-resistant precision ejector assembly according to claim 1, characterized in that: The inner side of the buffer base (1) is provided with an elastic buffer block (11), and the elastic buffer block (11) is interference-fitted with the tail of the needle bar (2).

7. The fatigue-resistant precision ejector assembly according to claim 1, characterized in that: The buffer base (1) is fixed to the mold plate by pressing.

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