Pushing mechanism for lead frame discharge box

Abstract

This invention relates to the field of feeding device technology, and discloses a feeding mechanism for a lead frame discharge box, including a connecting plate, a base, a push rod, a power motor, and an encoder. The connecting plate is installed on one side of the box storing the lead frame; the base is installed on the connecting plate, and the push rod passes through the base. Several bearing assemblies are arranged on the base and on at least one side of the push rod, with the bearing assemblies in rolling contact with the push rod; a rotating shaft is provided at the output end of the power motor, and a predetermined static friction force is formed between the rotating shaft and the push rod; a roller is provided at the measuring end of the encoder, and the roller is in rolling contact with the push rod. The above-mentioned feeding mechanism for the lead frame discharge box uses the bearing assemblies to limit and guide the push rod, ensuring the repeatability accuracy of the push rod. The power motor drives the push rod to reciprocate, avoiding damage to the lead frame from large impacts. Furthermore, the encoder monitors the movement state of the push rod, ensuring the accuracy of the push rod's action.

Description

Technical Field

[0001] This invention relates to the field of feeding device technology, and in particular to a feeding mechanism for a lead wire frame discharge box. Background Technology

[0002] Leadframes, as a key carrier of chips in semiconductor packaging processes, are typically stored in stacked cassettes. On automated packaging production lines, a pusher mechanism is used to eject the leadframes from the cassettes one by one for subsequent processes. The stability, speed, and compatibility of the pusher mechanism directly affect the overall line cycle time and yield.

[0003] Some existing feeding methods use simple cylinder drives combined with linear guides, which have problems such as large inertial impact during high-speed feeding, easy damage to the lead frame, and low accuracy of repetitive actions, affecting the quality of subsequent processing. Summary of the Invention

[0004] Based on the above, the purpose of this invention is to provide a pusher mechanism for a lead frame ejection box, which can accurately, without damage, and stably eject the lead frame from the box, thus meeting the requirements of high-precision processing.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A pusher mechanism for a lead frame discharge box includes a connecting plate, a base, a push rod, a power motor, and an encoder, wherein: The connecting plate is installed on one side of the material box that stores the lead frame; The base is mounted on the connecting plate, and the push rod passes through the base. Several bearing assemblies are provided on the base and on at least one side of the push rod. The bearing assemblies are in rolling contact with the push rod and are used to limit and guide the push rod. The output end of the power motor is equipped with a rotating shaft. A set static friction force is formed between the rotating shaft and the push rod. The power motor is used to drive the push rod to move back and forth, so that the push rod can pass through the connecting plate and extend into the material box to push a single lead frame. The encoder's measuring end is equipped with rollers that make rolling contact with the push rod. The encoder is used to monitor the push rod's moving distance and speed.

[0006] As an alternative, an O-ring is provided on the surface of the rotating shaft. The O-ring contacts and engages with the push rod. When the impact force on the push rod is greater than the static friction force, the O-ring slips off the push rod.

[0007] As an alternative, a pressure rod is provided on one side of the push rod, one end of which is rotatably connected to the base, and the encoder is installed on the other end of the pressure rod. A first spring is provided on the base to act on the pressure rod, and the first spring is used to keep the roller on the encoder pressed against the push rod.

[0008] As an optional solution, a slotted photoelectric switch is provided on the base, and a push rod passes through the slotted photoelectric switch. A through hole is provided on the push rod. When the head of the push rod is completely retracted from the material box into the base, the through hole is in the slot cavity of the slotted photoelectric switch, so that the beam of the slotted photoelectric switch can pass through the push rod. The slotted photoelectric switch is used to monitor the reset status of the push rod and the push rod's action count.

[0009] As an alternative, the push rod has a push block at its head and a stop screw at its end, which limits the maximum extension displacement of the push rod.

[0010] As an alternative, the bearing assembly includes a shoulder screw erected on the base, two bearings mounted on the shoulder screw, a first washer between the two bearings, a second washer between the lower bearing and the base, and flanges on the two bearings respectively, with the upper and lower edges of the push rod limited by the two flanges.

[0011] As an alternative, the two bearing assemblies are located on the same side of the push rod, while the shaft and roller are located on the other side of the push rod.

[0012] As an alternative, a cover plate is provided on the base, the push rod passes between the cover plate and the base, and the power motor is mounted on the cover plate.

[0013] As an alternative, a pressure plate is provided on the side of the base, and a positioning screw is provided on the pressure plate that extends into the side of the cover plate. A second spring is fitted on the positioning screw.

[0014] As an optional solution, the connecting plate is provided with a vertical adjustment groove, and a connecting screw that is fixed to the base passes through the vertical adjustment groove, so that the height of the base can be adjusted.

[0015] The beneficial effects of this invention are: The lead frame discharge box uses a pusher mechanism that uses a bearing assembly to limit and guide the pusher rod, ensuring the repeatability and accuracy of the pusher rod. The pusher rod is driven to move back and forth by a power motor, and the driving force can only be transmitted within the set range of static friction force to avoid damage to the lead frame from large impact forces. The motion status of the pusher rod is monitored by an encoder to ensure the accuracy of the pusher rod's action, thereby meeting the action requirements of pushing the lead frame out of the box. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the pusher mechanism for the lead frame discharge box provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the pusher mechanism for removing the base of the lead frame discharge box provided in an embodiment of the present invention; Figure 3This is a schematic diagram of the pusher mechanism for removing the cover plate and the power motor of the lead frame discharge box provided in an embodiment of the present invention.

[0017] In the attached image: 1. Connecting plate; 2. Base; 3. Push rod; 4. Power motor; 5. Encoder; 6. Rotating shaft; 7. Roller; 8. O-ring; 9. Pressure rod; 10. First spring; 11. Slotted photoelectric switch; 12. Through hole; 13. Push block; 14. Stop screw; 15. Shoulder screw; 16. Bearing; 17. First washer; 18. Second washer; 19. Flange; 20. Cover plate; 21. Pressure plate; 22. Positioning screw; 23. Second spring; 24. Vertical adjustment slot; 25. Connecting screw. Detailed Implementation

[0018] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0019] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0020] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0021] In the description of this embodiment, terms such as "upper," "lower," "left," and "right" are based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of description and simplification of operation, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention.

[0022] Furthermore, the terms "first" and "second" are merely used to distinguish between different terms in description and do not have any special meaning.

[0023] Please see Figures 1 to 3 As shown, this embodiment provides a pushing mechanism for a lead frame discharge box, including a connecting plate 1, a base 2, a push rod 3, a power motor 4, and an encoder 5, wherein: Connecting plate 1 is installed on one side of the material box that stores the lead frame; The base 2 is mounted on the connecting plate 1, and the push rod 3 passes through the base 2. Several bearing assemblies are provided on the base 2 and on at least one side of the push rod 3. The bearing assemblies are in rolling contact with the push rod 3 and are used to limit and guide the push rod 3. The output end of the power motor 4 is provided with a rotating shaft 6. A set static friction force is formed between the rotating shaft 6 and the push rod 3. The power motor 4 is used to drive the push rod 3 to move back and forth, so that the push rod 3 can pass through the connecting plate 1 and extend into the material box to push a single lead frame. The measuring end of the encoder 5 is equipped with a roller 7, which makes rolling contact with the push rod 3. The encoder 5 is used to monitor the moving distance and speed of the push rod 3.

[0024] Therefore, the bearing assembly forms a limiting guide for the push rod 3, ensuring the repeatability accuracy of the push rod 3. The power motor 4 drives the push rod 3 to move back and forth, and the driving force can only be transmitted within the set range of static friction force, avoiding damage to the lead frame by large impact force. The encoder 5 monitors the movement state of the push rod 3, ensuring the accuracy of the push rod 3's action, thus meeting the action requirement of pushing the lead frame out of the material box.

[0025] Optionally, an O-ring 8 is provided on the surface of the rotating shaft 6. The O-ring 8 is in contact with the push rod 3. When the impact force on the push rod 3 is greater than the static friction force, the O-ring 8 slips with the push rod 3.

[0026] The O-ring 8 primarily serves as overload protection and shock absorption, while also helping to reduce operating noise. When the push rod 3 experiences abnormal impact or jamming, the O-ring 8 immediately slips, cutting off the rigid transmission and protecting the power motor 4 and lead frame. This controllable slippage effectively absorbs and releases sudden impact energy, acting like a mechanical "fuse." Replacing the O-ring 8 model allows adjustment of the static friction. Furthermore, as a wear part, the O-ring 8 has low maintenance costs.

[0027] Optionally, a pressure rod 9 is provided on one side of the push rod 3. One end of the pressure rod 9 is rotatably connected to the base 2. The encoder 5 is installed on the other end of the pressure rod 9. A first spring 10 is provided on the base 2 to act on the pressure rod 9. The first spring 10 is used to keep the roller 7 on the encoder 5 pressed against the push rod 3.

[0028] By utilizing the action of the first spring 10 on the pressure rod 9, the roller 7 of the encoder 5 is guaranteed to always maintain reliable contact with the surface of the push rod 3, accurately converting the linear motion of the push rod 3 into the measurable rotational motion of the encoder 5. This achieves accurate displacement measurement without direct contact, reduces the absolute dependence on the machining accuracy of the push rod 3 itself, and automatically compensates for slight wear or gaps by using the pressure of the first spring 10, maintaining the stability of long-term measurement.

[0029] Optionally, a slotted photoelectric switch 11 is provided on the base 2, and the push rod 3 passes through the slotted photoelectric switch 11. A through hole 12 is provided on the push rod 3. When the head end of the push rod 3 is completely retracted from the material box into the base 2, the through hole 12 is in the slot cavity of the slotted photoelectric switch 11, so that the beam of the slotted photoelectric switch 11 can pass through the push rod 3. The slotted photoelectric switch 11 is used to monitor the reset state of the push rod 3 and the action count of the push rod 3.

[0030] When push rod 3 extends, through hole 12 shifts, and the beam of light from slotted photoelectric switch 11 is blocked by push rod 3; when push rod 3 resets, through hole 12 allows the beam of light from slotted photoelectric switch 11 to pass through, thereby accurately and reliably determining whether push rod 3 has fully reset, and also accurately counting the number of reciprocations of push rod 3, that is, obtaining the number of lead frames pushed out, which is convenient for monitoring the material output.

[0031] Optionally, the push rod 3 is provided with a push block 13 at its head end and a stop screw 14 at its end. The stop screw 14 is used to limit the maximum extension displacement of the push rod 3.

[0032] The push block 13 increases the contact area between the push rod 3 and the lead frame, making the pushing process smoother and the force more even, avoiding local stress concentration that could damage the lead frame; the stop screw 14 limits the maximum extension stroke of the push rod 3 by mechanical hard limiting, preventing the push rod 3 from extending excessively due to control errors or other faults and accidentally hitting the material box.

[0033] Optionally, the bearing assembly includes a shoulder screw 15 erected on the base 2, two bearings 16 are provided on the shoulder screw 15, a first washer 17 is provided between the two bearings 16, a second washer 18 is provided between the lower bearing 16 and the base 2, and a flange 19 is provided on each of the two bearings 16, and the upper and lower edges of the push rod 3 are limited by the two flanges 19.

[0034] Two bearings 16 operate effectively, bearing radial force and ensuring smooth extension and retraction of the push rod 3, preventing jamming. Two flanges 19 limit the upper and lower edges of the push rod 3, effectively controlling its radial runout and oscillation during movement, ensuring motion accuracy. The first washer 17 and the second washer 18 are used to adjust the axial clearance of the bearings 16, ensuring assembly accuracy and reducing axial movement. Thus, the push rod 3 is provided with stable, low-friction, and precise guidance and support.

[0035] This embodiment provides a relatively stable layout scheme, such as Figure 2 As shown, the two bearing assemblies are located on the same side of the push rod 3, while the shaft 6 and roller 7 are located on the other side of the push rod 3.

[0036] In this layout, push rod 3 is supported on both sides, reducing cantilever bending moment and deformation. Furthermore, separating the support guidance and drive / measuring positions avoids functional interference, making assembly and debugging more convenient and ensuring even force distribution. Additionally, the number of bearing assemblies can be increased according to the length of push rod 3, and they can be distributed on both sides of push rod 3 as needed to further enhance the limiting and guiding effect.

[0037] Optionally, a cover plate 20 is provided on the base 2, the push rod 3 passes between the cover plate 20 and the base 2, and the power motor 4 is installed on the cover plate 20.

[0038] The cover plate 20 here is used for the installation of the power motor 4 and can also cover the push rod 3 to prevent foreign objects from falling into the interior and causing the push rod 3 to jam or malfunction, thus improving protection.

[0039] Furthermore, a pressure plate 21 is provided on the side of the base 2, and a positioning screw 22 is provided on the pressure plate 21 that extends into the side of the cover plate 20. A second spring 23 is sleeved on the positioning screw 22.

[0040] The lateral locking function of the positioning screw 22 on the pressure plate 21 enables the cover plate 20 to be more precisely fixed to the base 2, and the second spring 23 provides pre-tension to eliminate assembly gaps.

[0041] Optionally, the connecting plate 1 is provided with a vertical adjustment groove 24, and a connecting screw 25 fixed to the base 2 passes through the vertical adjustment groove 24, so that the height position of the base 2 is adjustable.

[0042] This improves the compatibility of the pusher mechanism of the lead frame discharge box with different models of material boxes.

[0043] In summary, the lead frame ejector box pusher mechanism achieves stable, precise, and reliable ejection. Its core lies in the combination of friction drive and mechanical limit, which ensures accurate positioning while providing overload buffering capability. Furthermore, the encoder 5 and slotted photoelectric switch 11 enable dual monitoring and feedback of the motion status, further enhancing the controllability and countability of the action. The lead frame ejector box pusher mechanism has a reasonable structural layout, stable support and guidance, and possesses advantages such as high adaptability, easy maintenance, and long-term stable operation, effectively meeting the lead frame feeding requirements in the semiconductor packaging field.

[0044] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A pusher mechanism for a lead frame discharge magazine, characterized by, It includes a connecting plate (1), a base (2), a push rod (3), a power motor (4), and an encoder (5), wherein: The connecting plate (1) is installed on one side of the box where the lead frame is stored; The base (2) is mounted on the connecting plate (1), the push rod (3) passes through the base (2), and a plurality of bearing assemblies are provided on the base (2) and on at least one side of the push rod (3). The bearing assemblies are in rolling contact with the push rod (3) and are used to limit and guide the push rod (3). The output end of the power motor (4) is provided with a rotating shaft (6), and a set static friction force is formed between the rotating shaft (6) and the push rod (3). The power motor (4) is used to drive the push rod (3) to move back and forth, so that the push rod (3) can pass through the connecting plate (1) and extend into the material box to push the single lead frame. The encoder (5) is equipped with a roller (7) at its measuring end. The roller (7) makes rolling contact with the push rod (3). The encoder (5) is used to monitor the moving distance and speed of the push rod (3).

2. The pusher mechanism for the lead frame discharge box according to claim 1, characterized in that, The surface of the rotating shaft (6) is provided with an O-ring (8), which is in contact with the push rod (3). When the impact force on the push rod (3) is greater than the static friction force, the O-ring (8) slips with the push rod (3).

3. The pusher mechanism for the lead frame discharge box according to claim 1, characterized in that, A pressure rod (9) is provided on one side of the push rod (3). One end of the pressure rod (9) is rotatably connected to the base (2). The encoder (5) is installed on the other end of the pressure rod (9). A first spring (10) is provided on the base (2) to act on the pressure rod (9). The first spring (10) is used to keep the roller (7) on the encoder (5) pressed against the push rod (3).

4. The pusher mechanism for the lead frame discharge box according to claim 1, characterized in that, A slotted photoelectric switch (11) is provided on the base (2). The push rod (3) passes through the slotted photoelectric switch (11), and a through hole (12) is provided on the push rod (3). When the head end of the push rod (3) is completely retracted from the material box into the base (2), the through hole (12) is in the slot cavity of the slotted photoelectric switch (11), so that the beam of the slotted photoelectric switch (11) can pass through the push rod (3). The slotted photoelectric switch (11) is used to monitor the reset state of the push rod (3) and the action count of the push rod (3).

5. The pusher mechanism for the lead frame discharge box according to claim 1, characterized in that, The push rod (3) has a push block (13) at its head end and a stop screw (14) at its end. The stop screw (14) is used to limit the maximum extension displacement of the push rod (3).

6. The pusher mechanism for the lead frame discharge box according to claim 1, characterized in that, The bearing assembly includes a shoulder screw (15) erected on the base (2), two bearings (16) are provided on the shoulder screw (15), a first washer (17) is provided between the two bearings (16), a second washer (18) is provided between the lower bearing (16) and the base (2), and a flange (19) is provided on each of the two bearings (16), and the upper and lower edges of the push rod (3) are limited by the two flanges (19).

7. The pusher mechanism for the lead frame discharge box according to claim 6, characterized in that, The two bearing assemblies are located on the same side of the push rod (3), and the shaft (6) and the roller (7) are located on the other side of the push rod (3).

8. The pusher mechanism for the lead frame discharge box according to claim 1, characterized in that, A cover plate (20) is provided on the base (2), the push rod (3) passes between the cover plate (20) and the base (2), and the power motor (4) is installed on the cover plate (20).

9. The pusher mechanism for the lead frame discharge box according to claim 8, characterized in that, A pressure plate (21) is provided on the side of the base (2), and a positioning screw (22) is provided on the pressure plate (21) extending into the side of the cover plate (20). A second spring (23) is sleeved on the positioning screw (22).

10. The pusher mechanism for the lead frame discharge box according to claim 1, characterized in that, The connecting plate (1) is provided with a vertical adjustment groove (24), and a connecting screw (25) fixed to the base (2) is inserted in the vertical adjustment groove (24), so that the height position of the base (2) is adjustable.

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