Connecting rod bottom dead center stop limiting structure for linkage of punching machine
By introducing a connecting rod bottom dead point stop limit structure on the punch press and utilizing an eccentric connecting rod and an active cam system, the problems of spring pressing instability and die impact are solved, a stable bottom dead point stop is achieved, the die life is extended, and the stamping quality is improved.
Patent Information
- Application Number
- CN202511141465.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-15
- Publication Date
- 2025-10-17
AI Technical Summary
The existing punch press uses springs to press materials during the stamping process, which has poor stability. After the material is stretched, the spring hits the mold, affecting the mold life. In addition, there is a lack of a bottom dead point stop angle, which makes it impossible to perform tasks such as blanking and stretching of the product.
The connecting rod bottom dead point stop limit structure is adopted, and the eccentric connecting rod is used for angle correction. In combination with the active cam and the labor-saving connecting rod, the bottom dead point stop angle is provided. The sliding channel composed of the guide fixed plate and the guide column is used to achieve stable downward pressure of the pull rod, eliminating the instability of the spring pressing and avoiding mold collision.
The stability of the pull rod downward pressure at the same angle is achieved, which avoids mold collision, extends the service life of the mold, and improves the quality and stability of the stamping process.
Smart Images
Figure CN120790773A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of punch, in particular to a connecting rod lower dead point stop limiting structure for punch linkage. BACKGROUND
[0002] The punch is a punch press. The stamping process has the advantages of saving materials and energy, high efficiency, low technical requirements for operators, and producing products that cannot be produced by machining through various molds, so its application is becoming more and more widely. Stamping production is mainly for sheet metal. Through the mold, it can make blanking, punching, forming, drawing, trimming, fine blanking, shaping, riveting and extrusion parts, etc., and is widely used in various fields.
[0003] The design principle of the punch is to convert circular motion into linear motion. The main motor drives the flywheel, and through the clutch, the gear, the crankshaft (or eccentric gear), the connecting rod and other parts are driven to rotate to achieve the linear motion of the slider. The movement from the main motor to the connecting rod is circular motion. The punch generally adopts the spring pressing method during the stamping process, but the spring pressing method has poor stability, and the spring will impact the mold to a certain extent after stretching the pressing material, thereby greatly affecting the service life of the mold. Moreover, the current punch does not have a lower dead point stop angle when pressing down, so it cannot realize the blanking, stretching and other work of the product, and therefore needs to be improved. SUMMARY
[0004] The purpose of the present application is to provide a connecting rod lower dead point stop limiting structure for punch linkage to solve the problem that the existing punch generally adopts the spring pressing method during the stamping process, but the spring pressing method has poor stability, and the spring will impact the mold to a certain extent after stretching the pressing material, thereby greatly affecting the service life of the mold, and the current punch does not have a lower dead point stop angle when pressing down, so it cannot realize the blanking, stretching and other work of the product.
[0005] In order to achieve the above object, the present application provides the following technical scheme: a connecting rod lower dead point stop limiting structure for punch linkage, comprising a punch frame, a punch capable of being pressed is arranged on the punch frame, and a lower die seat is arranged below the punch, a sliding channel is arranged in the lower die seat, a pull rod is movably inserted into the sliding channel, a guide fixed plate one is arranged on the part of the pull rod extending above the sliding channel, one or more guide columns are arranged on the guide fixed plate one, a guide fixed plate two is connected between the guide columns, a cutting material fixed plate is further arranged between the guide columns, and the cutting material fixed plate is further arranged on the punch frame, a cutting material concave die is arranged on the cutting material fixed plate, a cutting material pressure material knife edge is arranged below the guide fixed plate two, the punch can be inserted into the cutting material concave die after passing through the guide fixed plate two and the cutting material pressure material knife edge, a core deviation connecting rod is sleeved outside the pull rod after extending out of the sliding channel, a connecting rod support is arranged on the side of the lower die seat, a blanking and stretching limiting assembly capable of adjusting the core deviation connecting rod to compensate for displacement correction and limiting the pull rod is hingedly connected to the connecting rod support, the blanking and stretching limiting assembly comprises a transmission chain connected to a punch main shaft at one end, a driving cam, a follower wheel and a labor-saving connecting rod, the labor-saving connecting rod is hingedly connected to the connecting rod support through a hinging point one, the labor-saving connecting rod is hingedly connected to the follower wheel through a hinging point two at one end, the other end of the labor-saving connecting rod is connected to the core deviation connecting rod, the other end of the transmission chain is in transmission connection with the driving cam, and the driving cam cooperates with the follower wheel.
[0006] As a preferred, in order to realize more labor-saving operation, the hinging point one on the labor-saving connecting rod accounts for one third of the entire labor-saving connecting rod, the hinging point one on the labor-saving connecting rod accounts for two thirds of the entire labor-saving connecting rod, and the follower wheel is located at the end point of the two thirds away from the hinging point one.
[0007] As a preferred, in order to facilitate installation, a notch is arranged at one end of the labor-saving connecting rod, a positioning support is inserted into the notch, the positioning support is in screw connection with the notch through one or more mounting screws, and the follower wheel is hingedly connected below the positioning support.
[0008] As a preferred, in order to be able to adjust the length of the pull rod, the pull rod comprises an upper rod body and a lower rod body, an outer thread part one is arranged below the upper rod body, an outer thread part two is arranged above the lower rod body, a pull rod connecting block is arranged between the upper rod body and the lower rod body, an inner thread sleeve in screw connection with the outer thread part one and the outer thread part two is arranged in the pull rod connecting block, and the core deviation connecting rod is arranged outside the lower rod body.
[0009] As preferred, in order to realize a certain force point when the pull rod is pressed down, ensure more stable force, the outer side below the lower rod body is further sleeved with a sliding block, the punch frame is provided with a guide sliding rail, the sliding block is slidingly connected on the guide sliding rail, the sliding block is hinged and positioned on the pull rod through a positioning shaft one transversely penetrating the sliding block and the pull rod.
[0010] As preferred, the eccentric core connecting rod is connected with the lower rod body through a positioning shaft two, the positioning shaft two transversely penetrates the eccentric core connecting rod and the lower rod body to realize hinging and positioning of the eccentric core connecting rod on the pull rod, and the positioning shaft two is sleeved with an anti-skid shaft sleeve.
[0011] As preferred, in order to facilitate later disassembly, the lower die seat is provided below with two positioning columns arranged at intervals, the pull rod guide plate is fixed below the two positioning columns through locking screws, and the pull rod is connected with the eccentric core connecting rod after penetrating the pull rod guide plate.
[0012] As preferred, in order to facilitate installation, the upper side of the pull rod is provided with a limiting boss, and the limiting boss is threadedly connected with the guide fixed plate through one or more than one positioning screw.
[0013] As preferred, in order to ensure the stability of replacement, the guide column has four, and the four guide columns are respectively located on the four sides of the outer side of the pull rod.
[0014] Compared with the prior art, the beneficial effects of the present application are: the present structure utilizes the eccentric core connecting rod to correct the angle, finally ensures that the force of the pull rod 4 downwardly pressing is always at the same angle of downward pressing, does not allow force dispersion, finally realizes the work of blanking, stretching and blanking by using the active cam to provide a lower dead point stop angle, and the problem of poor stability caused by spring pressing is omitted, further avoiding the problems of impact of traditional knife edge and secondary die impact after blanking and stretching, prolonging the service life of the die and improving the quality of the stamping process. BRIEF DESCRIPTION OF DRAWINGS
[0015] Figure 1 It is a side structure schematic view of the lower dead point stop limiting structure of the punch linkage connecting rod in the present embodiment 1.
[0016] Figure 2 It is an exploded structure schematic view of the pull rod in the present embodiment 1.
[0017] Figure 3 It is an enlarged view of A of Figure 1 .
[0018] Figure 4 It is an enlarged view of B of Figure 1 .
[0019] In the figure: punch press frame 1, punch 2, lower die seat 3, sliding channel 301, pull rod 4, upper rod body 401, lower rod body 402, outer thread part one 403, outer thread part two 404, guide fixed plate one 5, guide column 6, guide fixed plate two 7, cutting material fixed plate 8, cutting material concave die 9, cutting material pressure material knife edge 10, core deviation connecting rod 11, connecting rod support 12, transmission chain 13, driving cam 14, driven wheel 15, labor-saving connecting rod 16, hinged point one 161, hinged point two 162, notch 163, positioning support 17, mounting screw 18, pull rod connecting block 181, internal thread sleeve 19, sliding block 20, guide sliding rail 21, positioning shaft one 22, pull rod guide plate 23, locking screw 24, positioning shaft two 25, anti-skid shaft sleeve 251, positioning column 26, limiting boss 27, positioning screw 28. DETAILED DESCRIPTION
[0020] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative labor fall within the scope of the present application.
[0021] In addition, the terms "first", "second" are used only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise specifically limited.
[0022] Embodiment 1
[0023] Please refer to Figures 1-4As shown, the punch linkage connecting rod lower dead point stop limiting structure disclosed by the embodiment comprises a punch frame 1, the punch frame 1 is provided with a punch 2 capable of being pressed downward and a lower die seat 3 located below the punch 2, a sliding channel 301 is arranged in the lower die seat 3, a pull rod 4 is movably inserted into the sliding channel 301, a guide fixed plate one 5 is arranged on the part of the pull rod 4 extending above the sliding channel 301, one or more guide columns 6 are arranged on the guide fixed plate one 5, a guide fixed plate two 7 is connected between the guide columns 6, a cutting material fixed plate 8 is further arranged between the guide columns 6 and on the punch frame 1, a cutting material concave die 9 is arranged on the cutting material fixed plate 8, a cutting material pressing knife edge 10 is arranged below the guide fixed plate two 7, the punch 2 can be inserted into the cutting material concave die 9 after passing through the guide fixed plate two 7 and the cutting material pressing knife edge 10, a core deflection connecting rod 11 is sleeved outside the pull rod 4 after the pull rod 4 extends out of the sliding channel 301, a connecting rod support 12 is arranged on the side of the lower die seat 3, a blanking and stretching limiting assembly capable of adjusting the core deflection connecting rod 11 to displace, compensate and correct and capable of limiting the pull rod 4 is hingedly connected to the connecting rod support 12, the blanking and stretching limiting assembly comprises a transmission chain 13 connected to a punch main shaft at one end, a driving cam 14, a follower 15 and a labor-saving connecting rod 16, the labor-saving connecting rod 16 is hingedly connected to the connecting rod support 12 through a hinge point one 161, the labor-saving connecting rod 16 is hingedly connected to the follower 15 through a hinge point two 162 at one end, the other end of the labor-saving connecting rod 16 is connected to the core deflection connecting rod 11, the other end of the transmission chain 13 is in transmission connection with the driving cam 14, the driving cam 14 cooperates with the follower 15, in order to ensure the stability of replacement, the guide columns 6 are four in total, and the four guide columns 6 are respectively located on the four sides outside the pull rod 4, in order to facilitate installation, a notch 163 is arranged at one end of the labor-saving connecting rod 16, a positioning support 17 is inserted into the notch 163, the positioning support 17 is in screw connection with the notch 163 through one or more mounting screws 18, the follower 15 is hingedly connected below the positioning support 17, and the positioning support 17 is quickly fixed in the notch 163 through the mounting screws 18.
[0024] As preferred, in order to realize more labor-saving operation, the hinge point one 161 on the labor-saving connecting rod 16 and one end of the labor-saving connecting rod 16 account for one third of the entire labor-saving connecting rod 16, the hinge point one 161 on the labor-saving connecting rod 16 and one end of the labor-saving connecting rod 16 account for two thirds of the entire labor-saving connecting rod 16, and the follower 15 is located at the end point of the two thirds of the labor-saving connecting rod 16 away from the hinge point one 161, in the structure, the hinge point one 161 is arranged at one third of the labor-saving connecting rod 16 after the entire connecting rod is equally divided into three parts, finally making the labor-saving connecting rod 16 swing in the form of a lever with the hinge point one 161, and the operation is more labor-saving.
[0025] As preferred, in order to adjust the length of the pull rod, the pull rod 4 comprises an upper rod body 401 and a lower rod body 402, the lower part of the upper rod body 401 is provided with an outer thread part one 403, the upper part of the lower rod body 402 is provided with an outer thread part two 404, a pull rod connecting block 181 is arranged between the upper rod body 401 and the lower rod body 402, an inner thread sleeve 19 is arranged in the pull rod connecting block 181, which is screwed with the outer thread part one 403 and the outer thread part two 404, and the eccentric connecting rod 11 is arranged outside the lower rod body 402. In this embodiment, in order to conveniently adjust the length of the pull rod, the pull rod 4 is arranged in two parts, i.e. the upper rod body 401 and the lower rod body 402, then the lower part of the upper rod body 401 is provided with the outer thread part one 403, the upper part of the lower rod body 402 is provided with the outer thread part two 404, and the inner thread sleeve 19 with upper and lower communication is arranged in the pull rod connecting block 181, so that the upper rod body 401 and the lower rod body 402 can be screwed with the inner thread sleeve 19, and finally the length of the whole pull rod 4 can be adjusted according to the length requirement, further realizing the universality of the pull rod 4 and being convenient for users to use.
[0026] As preferred, in order to realize a certain force point when the pull rod is pressed down, ensure more stable force, the outer side of the lower part of the lower rod body 402 is further sleeved with a sliding block 20, the punch machine frame 1 is provided with a guide sliding rail 21, the sliding block 20 is slidingly connected on the guide sliding rail 21, and the sliding block 20 is transversely penetrated through the sliding block 20 and the pull rod 4 by a positioning shaft one 22 to realize the hinged positioning of the sliding block 20 on the pull rod 4. In this embodiment, the sliding block 20 is square, and the pull rod 4 is circular. First, the sliding block 20 is sleeved on the pull rod 4, then the positioning shaft one 22 is transversely penetrated through the sliding block 20 and the pull rod 4 to realize the hinged positioning of the sliding block 20 on the pull rod 4, and the sliding block 20 is slidingly connected on the guide sliding rail 21. The positioning of the sliding block 20 makes the pull rod have a certain force point when it is pressed down, ensuring more stable force.
[0027] As preferred, the eccentric connecting rod 11 and the lower rod body 402 are connected through a positioning shaft two 25, the positioning shaft two 25 is transversely penetrated through the eccentric connecting rod 11 and the lower rod body 402 to realize the hinged positioning of the eccentric connecting rod 11 on the pull rod 4, and the positioning shaft two 25 is sleeved with an anti-skid shaft sleeve 251. In this embodiment, the positioning shaft two 25 enables the eccentric connecting rod 11 to slightly rotate, and the eccentric connecting rod 11 is further connected with the labor-saving connecting rod 16. When the left side of the labor-saving connecting rod 16 is lifted or lowered, the eccentric connecting rod 11 drives the pull rod 4 to be synchronously pulled down or lifted under the action of the hinged point one 161.
[0028] As preferred, in order to facilitate the later disassembly, the lower portion of the lower die seat 3 is provided with two positioning columns 26 arranged at intervals, and the lower portion between the two positioning columns 26 is fixed with a pull rod guide plate 23 through a locking screw 24. The lower portion of the pull rod 4 is connected with the eccentric core connecting rod 11 after passing through the pull rod guide plate 23. When assembling, the pull rod guide plate 23 is first placed below the two positioning columns 26, and then the locking screw 24 is passed through the corresponding through hole of the pull rod guide plate 23 and is screwed with the corresponding positioning column 26 to realize the connection of the pull rod guide plate 23. In this embodiment, the pull rod guide plate 23 is additionally arranged below the positioning column 26, and then the lower portion of the pull rod 4 is slidably arranged through the pull rod guide plate 23, which can play a guiding and positioning role when the pull rod 4 moves up and down. At the same time, in order to facilitate the installation, the upper portion of the pull rod 4 is provided with a limiting boss 27, and the limiting boss 27 is screwed with the guide fixed plate 1 5 through one or more than one positioning screw 28. When assembling, the limiting boss 27 is clamped in the corresponding groove of the guide fixed plate 1 5, and then the positioning screw 28 is screwed with the guide fixed plate 1 5 to realize the fixing function of the upper portion of the pull rod 4.
[0029] In the structure, the small punch press composed of guide fixed plate one 5, guide fixed plate two 7 and guide column 6 is arranged on the part of pull rod 4 extending out of lower die seat 3, so that cutting and pressing blade edge 10 can stop for a period of time under the downward pressing of pull rod 4, thereby realizing the downward pressing and stretching operation of the product. Compared with the ordinary crank punch press, the cutting and pressing blade edge 10 cannot stop for a period of time, so that the blanking, stretching and other work of the product cannot be realized. In the working process, guide fixed plate one 5 and guide fixed plate two 7 are connected with pull rod 4 through guide column 6, so that guide fixed plate one 5 and guide fixed plate two 7 can move up and down with pull rod 4, and finally drive cutting and pressing blade edge 10 to move downward. Since cutting fixed plate 8 is arranged on punch press frame 1, cutting fixed plate 8 is fixed and cannot move. In this embodiment, the transmission power of pull rod 4 is derived from blanking and stretching limiting component, and the specific structure of blanking and stretching limiting component is as follows: one end of transmission chain 13 is connected with the existing machine tool main shaft on punch press frame 1, the other end of transmission chain 13 is in transmission connection with driving cam 14, the side surface of driving cam 14 abuts against follow-up wheel 15, follow-up wheel 15 is hinged on a three times labor-saving labor-saving connecting rod 16, the other end of labor-saving connecting rod 16 is connected with eccentric core connecting rod 11. In the working process, driving cam 14 drives eccentric core connecting rod 11 through a three times labor-saving labor-saving connecting rod 16, and eccentric core connecting rod 11 drives pull rod 4 to move up and down. Since there is a certain angle in the rotation process of labor-saving connecting rod 16, there is a certain eccentric angle when pull rod 4 is pulled downward, so eccentric core connecting rod 11 is used to correct the angle, so as to ensure that the downward pressing force of pull rod 4 is always at the same angle, and the force is not dispersed, so as to realize the work of blanking, stretching and discharging by using the stop angle provided by driving cam 14, and the problem of poor stability caused by spring pressing is omitted, the problems of impact of traditional blade edge and secondary mold impact after blanking and stretching are further avoided, the service life of the mold is prolonged, and the quality of the stamping process is improved.
[0030] In the present embodiment, the motion track of the labor-saving connecting rod 16 is required as follows: from 280°-40°, the cam rotates 60 degrees, the driving cam 14 (the cam motion rotates counterclockwise) goes up from the lowest point, and the labor-saving connecting rod 16 moves from the highest point to the horizontal point; from 40°-120°, the driving cam 14 moves to the highest point and rotates 40°, and the labor-saving connecting rod 16 moves to the uppermost point; from 120°-160°, the labor-saving connecting rod 16 is at the uppermost point and is in a stop state - at this time, the stop operation of the pull rod 4 is realized; from 160°-210°, the cam rotates 50 degrees, at this time, the labor-saving connecting rod 16 moves from the uppermost point to the horizontal point position; from 210°-280°, a motion cycle ends, the labor-saving connecting rod 16 moves from the horizontal point position to the lowermost state, and the operation of a motion cycle is: the machine tool main shaft on the punch machine frame 1 drives the driving cam 14, the driving cam 14 generates torque to drive the labor-saving connecting rod 16, the lever motion of the labor-saving connecting rod 16 is limited in cooperation with the lower force point of the sliding block 20, and finally drives the pull rod 4 to reciprocate up and down to complete a stamping cycle.
[0031] Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements to part of the technical features, and any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.
Claims
1. A bottom dead point stop limit structure for a connecting rod of a punching machine linkage, comprising a punching machine frame (1), a punch (2) capable of pressing downward and a lower die base (3) located below the punch (2) being provided on the punching machine frame (1), characterized in that: A sliding channel (301) is provided in the lower die base (3), a pull rod (4) is movably inserted in the sliding channel (301), a guide fixing plate (5) is provided on the part of the pull rod (4) extending above the sliding channel (301), one or more guide pillars (6) are provided on the guide fixing plate (5), a guide fixing plate (7) is connected above all the guide pillars (6), a cutting fixing plate (8) is also provided between all the guide pillars (6), and the cutting fixing plate (8) is also provided on the punching machine frame (1), a cutting die (9) is provided on the cutting fixing plate (8), a cutting and pressing blade (10) is provided below the guide fixing plate (7), the punch (2) can be inserted into the cutting die (9) after passing through the guide fixing plate (7) and the cutting and pressing blade (10), and a biasing plate is provided on the outside of the pull rod (4) after extending from the sliding channel (301) below. The core connecting rod (11) is provided with a connecting rod bracket (12) on the side of the lower die base (3), and the connecting rod bracket (12) is hinged with a blanking stretching limit assembly that can adjust the eccentric connecting rod (11) for displacement compensation correction and can limit the pull rod (4). The blanking stretching limit assembly includes a transmission chain (13) connected to the punch main shaft at one end, an active cam (14), a follower wheel (15) and a labor-saving connecting rod (16). The effort-saving connecting rod (16) is hinged to the connecting rod bracket (12) through a hinge point 1 (161), one end of the effort-saving connecting rod (16) is hinged to the follower wheel (15) through a hinge point 2 (162), the other end of the effort-saving connecting rod (16) is connected to the eccentric connecting rod (11), the other end of the transmission chain (13) is transmission-connected to the active cam (14), and the active cam (14) cooperates with the follower wheel (15).
2. The bottom dead center stop limit structure of the connecting rod for the punch linkage according to claim 1, characterized in that: The hinge point 1 (161) on the effort-saving link (16) and one end of the effort-saving link (16) account for one third of the entire effort-saving link (16), the hinge point 1 (161) on the effort-saving link (16) and one end of the effort-saving link (16) account for two thirds of the entire effort-saving link (16), and the follower wheel (15) is located at an end point that is two thirds of the distance between the hinge point 1 (161) and the effort-saving link (16).
3. The bottom dead center stop limit structure of the connecting rod for the punch linkage according to claim 2, characterized in that: A notch (163) is provided at one end of the labor-saving connecting rod (16), a positioning bracket (17) is inserted into the notch (163), the positioning bracket (17) is threadedly connected to the notch (163) via one or more mounting screws (18), and the follower wheel (15) is hinged below the positioning bracket (17).
4. The bottom dead center stop limit structure for a connecting rod used in a punching machine linkage according to claim 1, 2 or 3, characterized in that: The pull rod (4) includes an upper rod body (401) and a lower rod body (402), wherein an external threaded portion 1 (403) is provided below the upper rod body (401), and an external threaded portion 2 (404) is provided above the lower rod body (402), and a pull rod connecting block (181) is provided between the upper rod body (401) and the lower rod body (402), wherein an internal threaded sleeve (19) is provided in the pull rod connecting block (181) and is threadedly connected to the external threaded portion 1 (403) and the external threaded portion 2 (404), and the eccentric connecting rod (11) is provided outside the lower rod body (402).
5. The bottom dead center stop limit structure of the connecting rod for the punch linkage according to claim 4, characterized in that: A slider (20) is also sleeved on the outer side below the lower rod body (402), and a guide rail (21) is provided on the punching machine frame (1). The slider (20) is slidably connected to the guide rail (21). The slider (20) is hingedly positioned on the pull rod (4) after the positioning shaft (22) passes through the slider (20) and the pull rod (4) horizontally.
6. The bottom dead center stop limit structure of the connecting rod for two punch presses according to claim 4, characterized in that: The eccentric connecting rod (11) and the lower rod body (402) are connected via a second positioning shaft (25). The second positioning shaft (25) passes through the eccentric connecting rod (11) and the lower rod body (402) transversely to realize the hinged positioning of the eccentric connecting rod (11) on the pull rod (4), and the outer surface of the second positioning shaft (25) is connected with an anti-slip shaft sleeve (251).
7. The bottom dead center stop limit structure of the connecting rod for the punch linkage according to claim 1, characterized in that: Two positioning columns (26) are arranged at intervals below the lower mold base (3), and a pull rod guide plate (23) is fixed between the two positioning columns (26) through a locking screw (24). The pull rod (4) passes through the pull rod guide plate (23) below and is connected to the eccentric connecting rod (11).
8. The bottom dead center stop limit structure for the connecting rod of the punching machine linkage according to claim 1, characterized in that: A limiting boss (27) is provided above the pull rod (4), and the limiting boss (27) is threadedly connected to the guide fixing plate (5) through one or more positioning screws (28).
9. The bottom dead center stop limit structure for a connecting rod used in a punching machine linkage according to claim 1, 2 or 3, characterized in that: There are four guide pillars (6) in total, and the four guide pillars (6) are respectively located on the four sides of the outer side of the pull rod (4).