Crankshaft connecting rod stroke adjusting device for a press

Abstract

The application discloses a crankshaft connecting rod stroke adjusting device of a press machine, which comprises a press machine body, a crankshaft rotatably arranged in the body, an eccentric sleeve and an adjusting sleeve arranged on the crankshaft, a clutch mechanism arranged on the opposite end surfaces of the eccentric sleeve and the adjusting sleeve, a first gear ring fixedly connected to the eccentric sleeve, a rotating shaft rotatably arranged on the adjusting sleeve, a first gear part arranged on the rotating shaft and engaged with the first gear ring, a second gear ring rotatably arranged on the end surface of the adjusting sleeve away from the eccentric sleeve, a second gear part arranged on the rotating shaft and engaged with the second gear ring, a plurality of indicating scales arranged on the second gear ring, an alignment mark arranged on the end surface of the adjusting sleeve with the second gear ring, and an observation hole arranged on the press machine body and used for observing the alignment mark. The crankshaft connecting rod stroke adjusting device of the press machine can indicate the rotation of the eccentric sleeve, and thus the alignment of the clutch mechanism can be judged by the operator during the adjustment, and the operation is more convenient and accurate without the aid of additional measuring tools.

Description

Technical Field

[0001] This invention belongs to the field of press technology, specifically relating to a crankshaft connecting rod stroke adjustment device for a press. Background Technology

[0002] A press is a general-purpose device used for stamping and forming sheet metal, forgings, and other materials. Its core transmission mechanism is often a crankshaft-connecting rod mechanism. The crankshaft rotation drives the connecting rod and slide block to perform reciprocating linear motion, achieving pressure processing of the workpiece. Due to differences in die height, forming process, and product specifications, it is often necessary to adjust the stroke of the press slide block. To make stroke adjustment possible, existing technologies commonly incorporate an adjustment structure within the crankshaft-connecting rod mechanism to change the eccentricity.

[0003] A common crankshaft connecting rod stroke adjustment device includes a crankshaft, an eccentric sleeve, and an adjusting sleeve. The eccentric sleeve is rotatably fitted onto the crankshaft, and the adjusting sleeve is also fitted onto the crankshaft and can slide axially along the crankshaft. A clutch mechanism is provided on the end faces of the adjusting sleeve and the eccentric sleeve opposite each other. Under normal operating conditions, the clutch mechanism is in a closed engagement state, and the rotational motion of the crankshaft is transmitted to the eccentric sleeve through the adjusting sleeve; the two rotate synchronously to achieve a stable stamping stroke. When stroke adjustment is required, the adjusting sleeve is first slid laterally to disengage the clutch mechanism between the adjusting sleeve and the eccentric sleeve. Then, the eccentric sleeve is rotated to change its angular position relative to the crankshaft. Because the engagement angle of the clutch mechanism between the eccentric sleeve and the adjusting sleeve changes, the effective radius of rotation of the eccentric sleeve is altered, thereby adjusting the slider stroke. After adjustment, the adjusting sleeve is pushed back laterally to re-close the clutch mechanism, completing the stroke adjustment.

[0004] To enable the clutch mechanism to transmit a large working torque, existing clutch mechanisms typically employ an end-face toothed structure: several protrusions are evenly distributed around the outer circumference of the crankshaft on the adjusting sleeve, while grooves matching these protrusions are evenly distributed around the corresponding end face of the eccentric sleeve. Both the grooves and protrusions are designed with a relatively wide circumferential width to meet load-bearing requirements. The characteristic of this structure is that the two can only smoothly engage and close the clutch mechanism when the protrusions on the adjusting sleeve and the grooves on the eccentric sleeve are perfectly aligned circumferentially. If there is an angular misalignment between the protrusions and grooves, the protrusions will directly impact the end face of the groove during the lateral movement of the adjusting sleeve, preventing engagement and potentially causing damage or impact to the tooth surface.

[0005] In practical use, because the aforementioned clutch mechanism is located entirely inside the press, workers cannot directly observe the alignment of the protrusion and the groove when adjusting the stroke. Therefore, in existing technology, operators must repeatedly try and calibrate using external measuring tools such as angle gauges and dial indicators to determine whether the two are aligned. This adjustment method is cumbersome, time-consuming, and extremely unintuitive, greatly reducing the efficiency and convenience of press stroke adjustment and increasing the risk of damage to parts due to misjudgment. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a crankshaft connecting rod stroke adjustment device for a press. This device can indicate the rotation of the eccentric sleeve, making it easier for operators to judge the alignment of the protrusion and groove during adjustment. It is more convenient and accurate to operate without the need for additional measuring tools.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a crankshaft connecting rod stroke adjustment device for a press, comprising a press body, a crankshaft rotatably mounted within the press body, an eccentric sleeve rotatably sleeved on the crankshaft, and an adjusting sleeve axially slidable on the crankshaft. The adjusting sleeve has a plurality of protrusions evenly distributed around the outer circumference of the crankshaft on its end face near the eccentric sleeve, and a plurality of grooves evenly distributed around the outer circumference of the crankshaft on the end face near the adjusting sleeve, matching the protrusions. A first toothed ring is fixedly connected to the eccentric sleeve. A rotating shaft is rotatably mounted on the adjusting sleeve. A first gear portion is provided at one end of the rotating shaft near the first gear ring, and the first gear portion meshes with the first gear ring. A second gear ring is rotatably mounted on the end face of the adjusting sleeve away from the eccentric sleeve. A second gear portion is provided on the rotating shaft, and the second gear ring meshes with the second gear portion. The second gear ring is provided with several indicator scales. An alignment mark is provided on the end face of the adjusting sleeve with the second gear ring. An observation port is provided on the press body, and the end of the adjusting sleeve with the alignment mark is aligned with the observation port. When adjusting the crankshaft connecting rod stroke of this press, the adjusting sleeve is first moved to the adjustment position where the protrusion and groove are disengaged, i.e., the adjusting sleeve moves away from the eccentric sleeve to the set adjustment position. At this time, the operator can operate by rotating the shaft through the observation port. During the rotation of the shaft, the first gear and the first gear ring drive the eccentric sleeve to rotate to achieve the adjustment. During the adjustment, the second gear drives the second gear ring to rotate. The angle of rotation of the second gear ring can be read from the alignment mark. The operator can know how much rotation is needed to align the protrusion and groove according to the press instruction manual. By observing the alignment mark during adjustment, the operator can easily judge the alignment of the protrusion and groove. The operation is more convenient and accurate, without the need for additional measuring tools. After the adjustment is completed, the adjusting sleeve is moved to the position where the protrusion and groove are engaged to complete the stroke adjustment.

[0008] In the above technical solution, preferably, one of the protrusions of the adjusting sleeve is axially provided with a movable groove, and the end face of the adjusting sleeve away from the eccentric sleeve is provided with a through hole communicating with the movable groove. A movable block is axially slidably provided in the movable groove. The movable block has guide surfaces on both sides of one end facing the plurality of grooves. A movable rod connecting the movable block is passed through the through hole. An elastic element is provided between the movable groove and the movable block to push the guide surfaces toward the grooves. When the adjusting sleeve is in the adjusting position where the plurality of protrusions are disengaged from the plurality of grooves, as the eccentric sleeve rotates, the movable block enters the plurality of grooves in sequence and moves back and forth. Only when the plurality of protrusions are aligned with the plurality of grooves, when the movable block extends into one of the grooves, the end of the movable rod is flush with the opening of the through hole to indicate that the plurality of protrusions are aligned with the plurality of grooves. When adjusting the crankshaft connecting rod stroke using this structure, with the adjusting sleeve in the adjustment position where the protrusions and grooves are disengaged, the rotation of the eccentric sleeve causes the movable block to sequentially enter the grooves. This causes the movable block to reciprocate axially within the movable slot, thereby driving the movable rod to reciprocate. Since the movable block extends into one of the grooves only when the protrusions and grooves are aligned, the end of the movable rod is flush with the opening of the through hole to indicate that the protrusions and grooves are aligned. Therefore, the operator can directly determine whether the protrusions and grooves are aligned by whether the end of the movable rod is flush with the opening of the through hole. There is no need to rely on the instruction manual; the angle adjustment and the determination of whether the protrusions and grooves are aligned can be completed directly by adjustment, making the operation more convenient and accurate.

[0009] In the above technical solution, preferably, the machine body is provided with a linear drive device for driving the axial movement of the adjusting sleeve, and a roller is provided at the junction of the drive end of the linear drive device and the adjusting sleeve. This structure allows the adjusting sleeve to move via the linear drive device, and the rolling of the roller reduces wear caused by relative movement between the drive end of the linear drive device and the adjusting sleeve.

[0010] In the above technical solution, preferably, a retaining plate is fixed on the crankshaft, and a return spring is provided between the retaining plate and the adjusting sleeve. This structure allows the adjusting sleeve to be pushed back to the transmission position where the protrusion and groove engage when the linear drive device resets after stroke adjustment is completed, via the return spring.

[0011] In the above technical solution, preferably, a guide ring is fixedly provided on the side of the crankshaft near the observation port, a third gear is provided at the end of the rotating shaft near the guide ring, a third gear ring is rotatably provided inside the guide ring, the third gear and the third gear ring mesh, retaining rings for blocking the third gear are provided on both ends of the third gear ring, a plurality of elastic insertion rod assemblies are provided on the side of the third gear ring, and the inner wall of the observation port is provided with insertion holes for the elastic insertion rod assemblies to be inserted to position the third gear ring. When the adjusting sleeve is in the adjusting position where the protrusion is disengaged from the plurality of grooves, the outer end of the insertion rod assembly abuts against or is inserted into the insertion hole of the inner wall of the observation port. When the adjusting sleeve is in the transmission position where the protrusion and the plurality of grooves are engaged, the outer end of the insertion rod assembly is separated from the inner wall. When adjusting the stroke using this structure, the adjusting sleeve is first moved to the adjustment position where the protrusion disengages from the groove. During the movement of the adjusting sleeve, the rotating shaft synchronously drives the third gear to move, and the third gear synchronously drives the third gear ring to move. When the adjusting sleeve moves to the adjustment position, the outer end of the insert rod assembly abuts against or inserts into the insertion hole of the observation port. Then, the crankshaft is driven to rotate slowly. The insert rod assembly will eventually insert into the insertion hole to fix the third gear ring. Afterward, the third gear ring and the third gear cooperate to drive the rotating shaft to rotate, which in turn drives the adjusting sleeve to rotate relative to the crankshaft. This eliminates the need for the operator to use tools such as wrenches to provide torque to rotate the rotating shaft, making the stroke adjustment more effortless and convenient. After the adjustment is completed, the adjusting sleeve is returned to the transmission position where the protrusion and groove are engaged.

[0012] In the above technical solution, preferably, the elastic insert rod assembly includes a guide hole disposed on the side of the second toothed ring, a limiting hole located on the retaining ring, a first spring located in the guide hole, and an insert rod inserted into the limiting hole, wherein one end of the insert rod located in the guide hole has a limiting protrusion ring. This elastic insert rod assembly has a simple structure and the insert rod will not detach from the second toothed ring.

[0013] Compared with the prior art, the present invention has the following advantages: When adjusting the crankshaft connecting rod stroke adjustment device of this press, the adjusting sleeve is first moved to the adjustment position where the protrusion and the groove are disengaged, that is, the adjusting sleeve is moved away from the eccentric sleeve to the set adjustment position. At this time, the operator can operate by rotating the shaft through the observation port. During the rotation of the shaft, the first gear part and the first gear ring drive the eccentric sleeve to rotate to achieve the adjustment. During the adjustment, the second gear part drives the second gear ring to rotate. The rotation angle of the second gear ring can be read through the alignment mark. The operator can know how much rotation angle is needed to align the protrusion and the groove according to the press instruction manual. While adjusting, the operator can easily judge the alignment of the protrusion and the groove by observing the alignment mark. The operation is more convenient and accurate, without the need for additional measuring tools. After the adjustment is completed, the adjusting sleeve is moved to the position where the protrusion and the groove are engaged to complete the stroke adjustment. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of Embodiment 1 of the present invention.

[0015] Figure 2 This is an exploded structural diagram of Embodiment 1 of the present invention.

[0016] Figure 3 This is a side view of the structure of Embodiment 1 of the present invention.

[0017] Figure 4 This is a cross-sectional structural diagram of Embodiment 1 of the present invention.

[0018] Figure 5 This is a schematic diagram of the structure of the second toothed ring in Embodiment 1 of the present invention.

[0019] Figure 6 This is a schematic diagram of the adjusting sleeve in Embodiment 1 of the present invention.

[0020] Figure 7 This is a schematic diagram of the structure of the active block in Embodiment 1 of the present invention.

[0021] Figure 8 This is a cross-sectional structural diagram of Embodiment 2 of the present invention. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: See also Figures 1 to 7Example 1: A crankshaft connecting rod stroke adjustment device for a press includes a press body. A crankshaft 1 is rotatably mounted inside the press body. An eccentric sleeve 2 is rotatably sleeved on the crankshaft 1. An adjusting sleeve 3 is axially slidable on the crankshaft 1. Several protrusions 4 are evenly distributed around the outer periphery of the crankshaft 1 on the end face of the adjusting sleeve 3 near the eccentric sleeve 2. Several grooves 5, matching the protrusions 4, are evenly distributed around the outer periphery of the crankshaft 1 on the end face of the adjusting sleeve 3 near the eccentric sleeve 2. A first toothed ring 6 is fixedly connected to the eccentric sleeve 2. A rotating shaft 7 rotatably passes through the adjusting sleeve 3. A first gear part 8 is provided at one end of the rotating shaft 7 near the first gear ring 6. The first gear part 8 meshes with the first gear ring 6. A second gear ring 9 is rotatably provided on the end face of the adjusting sleeve 3 away from the eccentric sleeve 2. A second gear part 10 is provided on the rotating shaft 7. The second gear ring 9 meshes with the second gear part 10. Several indicator scales 11 are provided on the second gear ring 9. An alignment mark 12 is provided on the end face of the adjusting sleeve 3 with the second gear ring 9. An observation port 13 is provided on the press body. The end of the adjusting sleeve 3 with the alignment mark 12 is aligned with the observation port 13. When adjusting the stroke of the crankshaft connecting rod in this press, the adjusting sleeve 3 is first moved to the adjustment position where the protrusion 4 is disengaged from the groove 5, that is, the adjusting sleeve 3 is moved away from the eccentric sleeve 2 to the set adjustment position. At this time, the operator can operate by rotating the rotating shaft 7 through the observation port 13. During the rotation of the rotating shaft 7, the first gear part 8 and the first gear ring 6 are driven to rotate the eccentric sleeve 2 to achieve the adjustment. During the adjustment, the second gear part 10 drives the second gear ring 9 to rotate. The rotation angle of the second gear ring 9 can be read by the indicator scale 11 aligned with the alignment mark 12. The operator can know how much rotation angle is needed to align the protrusion 4 and the groove 5 according to the press instruction manual. While adjusting, the operator can easily judge the alignment of the protrusion 4 and the groove 5 by observing the indicator scale 11 aligned with the alignment mark 12. The operation is more convenient and accurate, without the need for additional measuring tools. After the adjustment is completed, the adjusting sleeve 3 is moved to the position where the protrusion 4 and the groove 5 are engaged to complete the stroke adjustment. During the movement of the adjusting sleeve 3, the first gear part 8 always meshes with the first gear ring 6 and moves synchronously, while the second gear part 10 always meshes with the second gear ring 9 and moves synchronously. In this embodiment, the first gear ring 6 and the second gear ring 9 are the same size. It is easy for those skilled in the art to understand that in other embodiments, the first gear ring 6 and the second gear ring 9 may be different in size, as long as the rotation of the second gear ring 9 can indicate the rotation angle of the internal first gear ring 6.

[0023] In this embodiment, a movable groove 14 is axially provided at one of the protrusions 4 of the adjusting sleeve 3. A through hole 15 communicating with the movable groove 14 is provided on the end face of the adjusting sleeve 3 away from the eccentric sleeve 2. A movable block 16 is axially slidable in the movable groove 14. The movable block 16 has guide surfaces 17 on both sides of one end facing the plurality of grooves 5. The guide surfaces 17 are inclined or arc surfaces. A movable rod 18 connecting the movable block 16 is passed through the through hole 15. An elastic element 19 is provided between the movable groove 14 and the movable block 16 to push the guide surfaces 17 toward the grooves 5. The elastic element 19 is a spring sleeved on the movable rod 18. When the adjusting sleeve 3 is in the adjusting position where the plurality of protrusions 4 are disengaged from the plurality of grooves 5, the movable block 16 enters the plurality of grooves 5 in sequence and moves back and forth as the eccentric sleeve 2 rotates. Only when the plurality of protrusions 4 and the plurality of grooves 5 are aligned, when the movable block 16 extends into one of the grooves 5, the end of the movable rod 18 is flush with the opening of the through hole 15 to indicate that the plurality of protrusions 4 and the plurality of grooves 5 are aligned. When adjusting the stroke of the crankshaft 1 connecting rod using this structure, when the adjusting sleeve 3 is in the adjustment position where several protrusions 4 are disengaged from several grooves 5, the rotation of the eccentric sleeve 2 will cause the movable block 16 to enter several grooves 5 in sequence, causing the movable block 16 to reciprocate axially within the movable groove 14, thereby driving the movable rod 18 to reciprocate. Since the movable block 16 only extends into one of the grooves 5 when several protrusions 4 are aligned, the end of the movable rod 18 is flush with the opening of the through hole 15 to indicate that several protrusions 4 are aligned with several grooves 5, the operator can directly judge whether the protrusions 4 and grooves 5 are aligned by whether the end of the movable rod 18 is flush with the opening of the through hole 15. There is no need to rely on the instruction manual; the angle adjustment and the judgment of whether the protrusions 4 and grooves 5 are aligned can be completed directly by adjustment, making the operation more convenient and accurate.

[0024] In this embodiment, a linear drive device 20 for driving the axial movement of the adjusting sleeve 3 is provided inside the press body. A roller 21 is provided at the junction of the drive end of the linear drive device 20 and the adjusting sleeve 3. This structure enables the movement of the adjusting sleeve 3 to be driven by the linear drive device 20, and the rolling of the roller 21 reduces the wear of the relative movement between the drive end of the linear drive device 20 and the adjusting sleeve 3, thereby extending the service life of the components.

[0025] In this embodiment, a retaining plate 22 is fixed on the crankshaft 1, and a return spring 23 is provided between the retaining plate 22 and the adjusting sleeve 3. This structure allows the adjusting sleeve 3 to be pushed back to the transmission position where the protrusion 4 and the groove 5 are engaged when the linear drive device 20 resets after stroke adjustment is completed. Those skilled in the art will readily understand that if the retaining plate 22 is too large and obstructs the alignment mark 12 or the movable rod 18, openings need to be made on the retaining plate 22 to observe the alignment mark 12 and the movable rod 18.

[0026] See Figure 8Example 2 differs from Example 1 only in that: a guide ring 24 is fixedly provided on the side of the crankshaft 1 near the observation port 13, a third gear part 25 is provided on the end of the rotating shaft 7 near the guide ring 24, a third gear ring 26 is rotatably provided inside the guide ring 24, the third gear part 25 meshes with the third gear ring 26, a retaining ring 27 is provided on both ends of the third gear ring 26 to block the third gear part 25, a plurality of elastic insertion rod assemblies 28 are provided on the side of the third gear ring 26, and an insertion hole 29 is provided on the inner wall of the observation port 13 for the elastic insertion rod assembly 28 to be inserted to position the third gear ring 26. When the adjusting sleeve 3 is in the adjusting position where the protrusion 4 is disengaged from the plurality of grooves 5, the outer end of the elastic insertion rod assembly 28 abuts against or is inserted into the insertion hole 29 on the inner wall of the observation port 13. When the adjusting sleeve 3 is in the transmission position where the protrusion 4 is engaged with the plurality of grooves 5, the outer end of the elastic insertion rod assembly 28 is separated from the inner wall. When adjusting the stroke using this structure, the adjusting sleeve 3 is first moved to the adjustment position where the protrusion 4 is disengaged from the groove 5. During the movement of the adjusting sleeve 3, the rotating shaft 7 synchronously drives the third gear part 25 to move, and the third gear part 25 synchronously drives the third gear ring 26 to move. When the adjusting sleeve 3 moves to the adjustment position, the outer end of the insert rod assembly abuts against or is inserted into the insertion hole 29 of the observation port 13. Then, the crankshaft 1 is driven to rotate slowly. The insert rod assembly will eventually be inserted into the insertion hole 29 to fix the third gear ring 26. After that, the third gear ring 26 and the third gear part 25 cooperate to drive the rotating shaft 7 to rotate, which in turn drives the adjusting sleeve 3 to rotate relative to the crankshaft 1. Therefore, the operator does not need to use tools such as wrenches to provide torque to rotate the rotating shaft 7, making the stroke adjustment more labor-saving and convenient. After the adjustment is completed, the adjusting sleeve 3 is returned to the transmission position where the protrusion 4 and the groove 5 are engaged.

[0027] In this embodiment, the elastic insert rod assembly 28 includes a guide hole 34 disposed on the side of the second toothed ring 9, a limiting hole 30 located on the retaining ring 27, a first spring 31 located in the guide hole 34, and an insert rod 32 inserted into the limiting hole 30. One end of the insert rod 32 located in the guide hole 34 has a limiting protrusion 33. This elastic insert rod assembly 28 has a simple structure and the insert rod will not detach from the second toothed ring 9.

[0028] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A crankshaft connecting rod stroke adjustment device for a press, comprising a press body, wherein a crankshaft (1) is rotatably disposed within the press body, an eccentric sleeve (2) is rotatably sleeved on the crankshaft (1), and an adjusting sleeve (3) is axially slidably sleeved on the crankshaft (1), wherein a plurality of protrusions (4) are evenly distributed around the outer periphery of the crankshaft (1) on the end face of the adjusting sleeve (3) near the eccentric sleeve (2), and a plurality of grooves (5) matching the plurality of protrusions (4) are evenly distributed around the outer periphery of the crankshaft (1) on the end face of the eccentric sleeve (2) near the adjusting sleeve (3), characterized in that: A first toothed ring (6) is fixedly connected to the eccentric sleeve (2). A rotating shaft (7) is rotatably connected to the adjusting sleeve (3). A first gear part (8) is provided at one end of the rotating shaft (7) near the first toothed ring (6). The first gear part (8) meshes with the first toothed ring (6). A second toothed ring (9) is rotatably provided on the end face of the adjusting sleeve (3) away from the eccentric sleeve (2). A second gear part (10) is provided on the rotating shaft (7). The second toothed ring (9) meshes with the second gear part (10). A plurality of indicator scales (11) are provided on the second toothed ring (9). An alignment mark (12) is provided on the end face of the adjusting sleeve (3) with the second toothed ring (9). An observation port (13) is provided on the press body. The end of the adjusting sleeve (3) with the alignment mark (12) is aligned with the observation port (13).

2. The crankshaft connecting rod stroke adjustment device for a press as described in claim 1, characterized in that: A movable groove (14) is axially provided at one of the protrusions (4) of the adjusting sleeve (3). A through hole (15) communicating with the movable groove (14) is provided on the end face of the adjusting sleeve (3) away from the eccentric sleeve (2). A movable block (16) is axially slidably provided in the movable groove (14). The movable block (16) has guide surfaces (17) on both sides of one end facing one of the grooves (5). A movable rod (18) connecting the movable block (16) is passed through the through hole (15). A space is provided between the movable groove (14) and the movable block (16) to hold the movable block (16). The guide surface (17) pushes against the elastic element (19) of the groove (5). When the adjusting sleeve (3) is in the adjusting position where the protrusions (4) and the grooves (5) are disengaged, the movable block (16) moves back and forth into the grooves (5) in sequence as the eccentric sleeve (2) rotates. Only when the protrusions (4) and the grooves (5) are aligned, when the movable block (16) extends into one of the grooves (5), the end of the movable rod (18) is flush with the opening of the through hole (15) to indicate that the protrusions (4) and the grooves (5) are aligned.

3. The crankshaft connecting rod stroke adjustment device for a press as described in claim 1, characterized in that: The press body is provided with a linear drive device (20) for driving the adjusting sleeve (3) to move axially, and a roller (21) is provided at the drive end of the linear drive device (20) where it connects with the adjusting sleeve (3).

4. The crankshaft connecting rod stroke adjustment device for a press as described in claim 3, characterized in that: A retaining plate (22) is fixed on the crankshaft (1), and a return spring (23) is provided between the retaining plate (22) and the adjusting sleeve (3).

5. The crankshaft connecting rod stroke adjustment device for a press as described in claim 1, characterized in that: A guide ring (24) is fixedly provided on the side of the crankshaft (1) near the observation port (13). A third gear part (25) is provided at the end of the rotating shaft (7) near the guide ring (24). A third gear ring (26) is rotatably provided inside the guide ring (24). The third gear part (25) meshes with the third gear ring (26). Retaining rings (27) for blocking the third gear part (25) are provided on both ends of the third gear ring (26). Several elastic insert rod assemblies (28) are provided on the side of the third gear ring (26). The inner wall of the observation port (13) is provided with a socket (29) for the insertion of the elastic rod assembly (28) to position the third toothed ring (26). When the adjusting sleeve (3) is in the adjusting position where the protrusion (4) is disengaged from the grooves (5), the outer end of the elastic rod assembly (28) abuts against or is inserted into the socket (29) of the inner wall of the observation port (13). When the adjusting sleeve (3) is in the transmission position where the protrusion (4) is engaged with the grooves (5), the outer end of the elastic rod assembly (28) is separated from the inner wall.

6. The crankshaft connecting rod stroke adjustment device for a press as described in claim 5, characterized in that: The elastic insert assembly (28) includes a guide hole (34) disposed on the side of the second toothed ring (9), a limiting hole (30) located on the retaining ring (27), a first spring (31) located in the guide hole (34), and an insert rod (32) inserted in the limiting hole (30). One end of the insert rod (32) located in the guide hole (34) has a limiting protrusion (33).

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