A large load release device and a design method thereof

Abstract

The present application relates to a kind of big load release device and its design method, including fixed hook, movable hook, convex-shaped connecting rod and triangular plate four-bar linkage, fixed hook and movable hook are rotatably connected by rotating pin shaft, four-bar linkage carries load, first limit rod and second limit rod are rotatably connected with the convex-shaped connecting rod in four-bar linkage, first limit rod and second limit rod are installed on the outer side of fixed hook by connecting rod, the middle part of connecting rod is provided with through-hole, the side of fixed hook is equipped with buffer rod, buffer rod passes through the through-hole in the middle part of connecting rod, the side end of fixed hook is also equipped with drive mechanism, the output end of drive mechanism corresponds with first limit rod and second limit rod, drive mechanism pushes first limit rod and second limit rod to lift up.By limit shaft and safety pin hole constitute double security, protect workpiece and personnel safety, structure design is reliable, with practicality.

Description

Technical Field

[0001] This invention relates to the field of high-energy impact testing equipment technology, and in particular to a high-load release device and its design method. Background Technology

[0002] In impact testing, the drop test is commonly used to assess the impact stiffness and strength of the tested component. The drop test involves raising the load to a certain height and then releasing it instantaneously, allowing it to fall freely and impact the tested component. The load release device is one of the core components of the impact testing equipment, used to grasp and release the load. The reliability and ease of operation of the load release device determine the safety and efficiency of the testing equipment.

[0003] Existing load release devices lack structural strength and reliability, often resulting in insecure load gripping. During the lifting process, the load is prone to falling off, causing injury to personnel and damage to the workpiece. Summary of the Invention

[0004] To address the shortcomings of existing production technologies, the applicant provides a structurally sound large load release device and its design method. By employing a four-bar linkage to control the opening and closing of the moving hook, the structural strength and reliability of the load release device are ensured. Furthermore, by setting a safety pin hole, the release device is guaranteed not to open during load lifting, thereby ensuring the safety of the load release device.

[0005] The technical solution adopted in this invention is as follows:

[0006] A design method for a large load release device includes a four-bar linkage consisting of a fixed hook, a movable hook, a convex connecting rod, and a triangular plate. The fixed hook and the movable hook are rotatably connected by a rotating pin. The four-bar linkage bears the load.

[0007] To ensure that the angles of the force-bearing surfaces of the fixed and movable grab hooks are symmetrical, and to ensure that the movable grab hook can open automatically under the gravity of the load, the angles of the first inclined surface on the fixed grab hook and the second inclined surface on the movable grab hook are designed.

[0008] Force analysis is performed on the contact surface between the moving hook and the load, i.e., the second inclined plane:

[0009] Let the angle between the second inclined plane and the horizontal direction be α. Then the second inclined plane needs to bear the gravity F of the load perpendicular to the horizontal direction. Decompose the gravity F into F1, F2 and F3.

[0010] Wherein, F1 represents the normal force borne by the force-bearing surface of the moving hook, and the direction of F1 is perpendicular to the second inclined plane. F1 is expressed by the following formula:

[0011] F1=F / cosα (1)

[0012] F2 represents the force that causes the moving hook to rotate. The direction of F2 is perpendicular to the lever arm of the torque of the moving hook. F2 is expressed by the following formula:

[0013] F2=F1·sin(α-α1) (2)

[0014] In the formula, α1 represents the angle between the lever arm of the rotational torque of the moving grab hook and the vertical direction;

[0015] F3 represents the frictional force that opposes the rotation of the moving hook. The direction of F3 is parallel to the second inclined plane, and F3 is expressed by the following formula:

[0016] F3=μ·F1 (3)

[0017] In the formula, μ represents the coefficient of friction. The fixed and moving grippers are made of 65Mn spring steel, and the connecting pin is made of 40Cr alloy steel. The coefficient of friction μ is 0.15.

[0018] During the design calculations, to ensure that the moving gripper can be released, the following formula must be satisfied:

[0019] F2·L-F3·cos(α-α1) ·L-μ·F·R≥0 (4)

[0020] In the formula, L represents the lever arm length of the rotational torque of the moving hook, and R represents the radius of the rotating pin that rotatably connects the fixed hook and the moving hook, R = 25mm;

[0021] Simplifying, we get:

[0022] sin(α-α1) ·L / cosα-μ·cos(α-α1) ·L / cosα-μ·R≥0 (5)

[0023] If the angles of the force-bearing surfaces of the fixed and movable grab hooks are symmetrical, then the angle between the first inclined plane and the horizontal direction is 180°-α.

[0024] Increasing the angle between the second inclined plane and the horizontal direction to α, or decreasing the angle α1 between the lever arm of the torque that causes the moving hook to rotate and the vertical direction, can both increase the force F2 that causes the moving hook to rotate.

[0025] A large load release device designed using the design method described in claim 1 includes a first limiting rod and a second limiting rod rotatably connected to a U-shaped connecting rod in a four-bar linkage. The first limiting rod and the second limiting rod are mounted on the outer side of a fixed grab hook via a connecting rod. A through hole is provided in the middle of the connecting rod. A buffer rod is installed on the side of the fixed grab hook. The buffer rod passes through the through hole in the middle of the connecting rod. A drive mechanism is also installed on the side end of the fixed grab hook. The output end of the drive mechanism corresponds to the first limiting rod and the second limiting rod. The drive mechanism pushes the first limiting rod and the second limiting rod to lift upward.

[0026] The fixed grab hook, the movable grab hook, the convex connecting rod, and the triangular plate are all integral structures;

[0027] The structure of the fixed hook is as follows: it includes a fixed hook body, a first groove and a second groove are provided on the side end of the fixed hook body, corresponding triangular plate mounting pin holes are provided on the two sides inside the first groove, corresponding movable hook mounting pin holes are provided on the two sides inside the second groove, a first hook-shaped structure is provided below the second groove, the first hook-shaped structure is provided with a first inclined surface, the first inclined surface is at an angle of 165.5° with the horizontal direction, the first hook-shaped structure is also provided with a first end face that cooperates with the movable hook, a second mounting plate and a third mounting plate for mounting the drive mechanism are provided on the other side end of the fixed hook body, a first mounting plate for mounting the buffer rod is provided above the second mounting plate, and limit shafts are provided on both sides of the fixed hook body, with mounting holes provided above the limit shafts;

[0028] The structure of the movable grab hook is as follows: it includes a second hook-shaped structure corresponding to the first hook-shaped structure. The second hook-shaped structure is provided with a second end face. When the movable grab hook is closed, the second end face fits tightly with the first end face. The second hook-shaped structure is also provided with a second inclined surface symmetrical to the first inclined surface. The angle between the second inclined surface and the horizontal direction is 14.5°. A protrusion is provided on the top of the second hook-shaped structure. The side of the protrusion has a fixed grab hook mounting pin hole and a first convex connecting rod mounting pin hole.

[0029] The structure of the convex connecting rod is as follows: it includes a protruding part, the side of the protruding part is provided with a limit rod mounting pin hole, the bottom of the protruding part is provided with an open structure, the middle of the open structure is provided with a through groove, the two sides of the through groove are provided with corresponding first safety pin holes, the lower part of the first safety pin hole is provided with a corresponding second pin hole, and the lower part of the second pin hole is provided with a corresponding first pin hole.

[0030] The structure of the triangular plate is as follows: it includes a triangular plate body, and the three inner corners of the side of the triangular plate body are respectively provided with a fifth pin hole, a second convex connecting rod mounting pin hole and a second safety pin hole.

[0031] As a further improvement to the above technical solution:

[0032] The protrusion of the movable grab hook is fitted into the second groove of the fixed grab hook.

[0033] The fixed hook mounting pin hole and the movable hook mounting pin hole are connected by a pin shaft, and the first convex connecting rod mounting pin hole and the first pin hole are connected by a pin shaft.

[0034] The triangular plate is installed by engaging with the fixed hook through the first groove, and the triangular plate is installed by engaging with the convex connecting rod through the through groove of the convex connecting rod.

[0035] The fifth pin hole is connected to the triangular plate mounting pin hole by a pin engagement, and the second convex connecting rod mounting pin hole is connected to the second pin hole by a pin engagement.

[0036] When the fixed hook and the moving hook are closed, the first safety pin hole and the second safety pin hole enable the four-bar linkage mechanism to self-lock by inserting the safety pin shaft.

[0037] The first limiting rod has a first limiting groove on its side that mates with the limiting shaft, and the second limiting rod has a second limiting groove that mates with the limiting shaft.

[0038] The drive mechanism has the following structure: it includes a motor, the output end of which is connected to a T-shaped block, and the T-shaped block constrains the first limiting rod and the second limiting rod to move downward.

[0039] The beneficial effects of this invention are as follows:

[0040] This invention features a compact and reasonable structure, and is easy to operate. By designing a four-bar linkage consisting of a fixed gripping hook, a movable gripping hook, a triangular plate, and a convex connecting rod, the structural strength and reliability of the load release device are ensured. Furthermore, by setting a safety pin hole, the release device is guaranteed not to open during the load lifting process, thereby ensuring the safety of the load release device.

[0041] The present invention also has the following advantages:

[0042] (1) By designing the V-shaped inclined plane angle through mechanical analysis, the rotational torque M generated by the moving grab hook is greater than or equal to 0 and as small as possible. This ensures that the load release device can release the load and minimizes the impact force of the load on the release device at the moment of load release, thus extending the service life of the release device.

[0043] (2) The present invention uses a limit rod and a safety pin to form a double safety guarantee. Even if personnel misoperate, the device will not be opened, thereby protecting the safety of personnel and workpieces.

[0044] (3) The present invention is provided with a buffer rod, which can constrain the movement of the limit rod at the moment of load release, and protect the limit rod and the load release device.

[0045] (4) The present invention uses a common motor on the market as the driving method, which is easy to purchase and easy to replace when the motor is damaged. Attached Figure Description

[0046] Figure 1 This is a schematic diagram of the structure of the present invention.

[0047] Figure 2 for Figure 1 The main view.

[0048] Figure 3 for Figure 1 The right view.

[0049] Figure 4 This is an exploded view of the present invention.

[0050] Figure 5 This is a schematic diagram of the fixed gripper hook in this invention.

[0051] Figure 6 for Figure 5 The main view.

[0052] Figure 7 for Figure 5 The right view.

[0053] Figure 8 This is a schematic diagram of the moving gripper hook in this invention.

[0054] Figure 9 This is a schematic diagram of the convex-shaped connecting rod in this invention.

[0055] Figure 10 for Figure 9 The main view.

[0056] Figure 11 This is a schematic diagram of the load capture process of the present invention.

[0057] Figure 12 This is a schematic diagram of the present invention when it is opened.

[0058] Figure 13 This is a schematic diagram of the force analysis of the second inclined plane in this invention.

[0059] The components include: 1. Fixed gripper hook; 2. Movable gripper hook; 3. T-shaped connecting rod; 4. First limiting rod; 5. Second limiting rod; 6. Connecting rod; 7. Buffer rod; 8. Triangular plate; 9. Drive mechanism; 10. Load.

[0060] 101. Mounting hole; 102. Limiting shaft; 103. Moving hook mounting pin hole; 104. Triangular plate mounting pin hole; 105. First mounting plate; 106. Second mounting plate; 107. Third mounting plate; 108. First inclined surface; 109. First groove; 110. Second groove; 111. Fixed hook body; 112. First end face; 113. First hook-shaped structure;

[0061] 201. Fixed hook mounting pin hole; 202. First convex connecting rod mounting pin hole; 203. Second inclined surface; 204. Second hook-shaped structure; 205. Second end face; 206. Protrusion;

[0062] 301. First pin hole; 302. Second pin hole; 303. Limit rod mounting pin hole; 304. First safety pin hole; 305. Protrusion;

[0063] 401. Third pin hole; 402. First limiting groove; 403. First connecting hole;

[0064] 501, Fourth pin hole; 502, Second limiting groove; 503, Second connecting hole;

[0065] 801, Fifth pin hole; 802, Second U-shaped connecting rod mounting pin hole; 803, Second safety pin hole; 804, Triangular plate body;

[0066] 901. Motor; 902. T-block. Detailed Implementation

[0067] The specific embodiments of the present invention will now be described with reference to the accompanying drawings.

[0068] like Figures 1-13 As shown, a design method for a large load release device includes a fixed grab hook 1, a movable grab hook 2, a convex connecting rod 3 and a triangular plate 8 forming a four-bar linkage mechanism. The four-bar linkage mechanism is connected by a pin shaft and carries a load 10.

[0069] The angles of the force-bearing surfaces of the fixed hook 1 and the movable hook 2 are symmetrical. In order to ensure that the movable hook 2 can open automatically under the gravity of the load 10, the angles of the first inclined surface 108 set on the fixed hook 1 and the second inclined surface 203 set on the movable hook 2 are designed.

[0070] Force analysis is performed on the contact surface between the moving hook 2 and the load 10, i.e., the second inclined surface 203:

[0071] Figure 13 In the diagram, x represents the horizontal direction, y represents the vertical direction, and the distance between the lever arm L and the center line of the release device is S1.

[0072] Let the angle between the second inclined plane 203 and the horizontal direction x be α. Then the second inclined plane 203 needs to bear the weight F of the load 10 perpendicular to the horizontal direction x. The single-sided hook, i.e. the movable hook 2, bears half the weight G / 2 of the load 10, that is, F = G / 2, where G represents the weight of the load 10. The weight F is decomposed into F1, F2 and F3.

[0073] Wherein, F1 represents the normal force borne by the force-bearing surface of the moving hook 2, and the direction of F1 is perpendicular to the second inclined plane 203. F1 is expressed by the following formula:

[0074] F1=F / cosα (1)

[0075] F2 represents the force that causes the movable hook 2 to rotate. The direction of F2 is perpendicular to the lever arm of the torque of the movable hook 2. F2 is expressed by the following formula:

[0076] F2=F1·sin(α-α1) (2)

[0077] In the formula, α1 represents the angle between the lever arm of the rotational torque of the moving gripper hook 2 and the vertical direction y;

[0078] F3 represents the frictional force F3 that hinders the rotation of the movable hook 2. The direction of F3 is parallel to the second inclined plane 203, and F3 is expressed by the following formula:

[0079] F3=μ·F1 (3)

[0080] In the formula, μ represents the coefficient of friction. The fixed hook 1 and the moving hook 2 are made of 65Mn spring steel, the connecting pin is made of 40Cr alloy steel, and the coefficient of friction μ is 0.15.

[0081] In the design calculations, to ensure that the moving gripper (2) can be released, the following formula needs to be satisfied:

[0082] M=F2·L-F3·cos(α-α1) ·L-μ·F·R≥0 (4)

[0083] In the formula, L represents the lever arm length of the rotational torque of the movable grab hook 2, and R represents the radius of the rotating pin that rotatably connects the fixed grab hook 1 and the movable grab hook 2, that is, the radius of the mounting pin hole 103 of the movable grab hook, R = 25mm;

[0084] Simplifying, we get:

[0085] sin(α-α1) ·L / cosα-μ·cos(α-α1) ·L / cosα-μ·R≥0 (5)

[0086] According to equations (2) and (5), the condition for ensuring that the movable hook 2 can be released is not related to the gravity F of the load 10 borne by the second inclined plane 203, but to the angle α between the second inclined plane 203 and the horizontal direction, the angle α1 between the lever arm of the torque of the movable hook 2 and the vertical direction y, and the length L of the lever arm; increasing α or decreasing α1 can increase the force F2 that makes the movable hook 2 rotate.

[0087] In order to ensure the strength of the load release device, the angle α between the second inclined plane 203 and the horizontal direction is less than or equal to 15°. Equation (5) can be made to hold by reducing the angle α1. When α1 decreases, the lever arm length L will increase accordingly.

[0088] When α = 14.5° and S1 = 10mm, we can get L = 127.034mm and α1 = 4.51°. Substituting these values ​​into formula (5) to calculate the result, we find that the condition for formula (5) is not met, indicating that the moving hook 2 will not open automatically.

[0089] To ensure the strength of the gripper, it was decided not to increase the angle α further. Instead, the angle α1 was reduced to make equation (5) true. Reducing α1 can be achieved by reducing the value of S1.

[0090] When α = 14.5° and S1 = 9mm, we can get L = 127.217mm and α1 = 4.06°. Substituting these values ​​into formula (5) and calculating the result, we can see that the condition for formula (5) is met, indicating that the moving hook 2 can open automatically.

[0091] When the angle α between the second inclined plane 203 and the horizontal direction is set to 14.5°, the lever arm L of the rotational torque of the moving hook 2 needs to reach 127.217mm. Then the moving hook 2 can start automatically without the need for additional driving force.

[0092] Since the angles of the force-bearing surfaces of the fixed hook 1 and the movable hook 2 are symmetrical, the angle between the first inclined plane 108 and the horizontal direction is 180°-α, that is, the angle between the first inclined plane 108 and the horizontal direction is 165.5°.

[0093] The inclined plane angle obtained by the above method can ensure that the rotational torque M generated by the movable gripper hook 2 is greater than or equal to 0 and as close to small as possible while ensuring gripping strength. This ensures that the load release device can release successfully and that the impact force generated at the moment of load release is as small as possible.

[0094] Based on the above design method, a large load release device is designed, with the following structure and function:

[0095] A large load release device includes a four-bar linkage consisting of a fixed gripping hook 1, a movable gripping hook 2, a U-shaped connecting rod 3, and a triangular plate 8. The four-bar linkage is connected by a pin. The side of the U-shaped connecting rod 3 is rotatably connected to a first limiting rod 4 and a second limiting rod 5 via the pin. The first limiting rod 4 and the second limiting rod 5 are mounted on the outer side of the fixed gripping hook 1 via a connecting rod 6. A through hole is provided in the middle of the connecting rod 6. A buffer rod 7 is installed on the side of the fixed gripping hook 1, passing through the through hole in the middle of the connecting rod 6. A drive mechanism 9 is also installed on the side end of the fixed gripping hook 1. The output end of the drive mechanism 9 corresponds to the first limiting rod 4 and the second limiting rod 5, and the drive mechanism 9 pushes the first limiting rod 4 and the second limiting rod 5 upwards. A spring is fitted around the buffer rod 7 to restrain the movement of the first limiting rod 4 and the second limiting rod 5.

[0096] The fixed grab hook 1, the movable grab hook 2, the convex connecting rod 3, and the triangular plate 8 are all integrated structures;

[0097] The structure of the fixed hook 1 is as follows: it includes a fixed hook body 111. The side end of the fixed hook body 111 is provided with a first groove 109 and a second groove 110. The two sides inside the first groove 109 are provided with corresponding triangular plate mounting pin holes 104. The two sides inside the second groove 110 are provided with corresponding movable hook mounting pin holes 103. The bottom of the second groove 110 is provided with a first hook-shaped structure 113. The first hook-shaped structure 113 is provided with a first inclined surface 108. The angle between the first inclined surface 108 and the horizontal direction is 165.5°. The first hook-shaped structure 113 is also provided with a first end face 112 that cooperates with the movable hook 2. The other side end of the fixed hook body 111 is provided with a second mounting plate 106 and a third mounting plate 107 for mounting the drive mechanism 9. The top of the second mounting plate 106 is provided with a first mounting plate 105 for mounting the buffer rod 7. The two sides of the fixed hook body 111 are provided with limit shafts 102. The top of the limit shafts 102 is provided with mounting holes 101.

[0098] The structure of the movable hook 2 is as follows: it includes a second hook structure 204 corresponding to the first hook structure 113. The second hook structure 204 is provided with a second end face 205. When the movable hook 2 is closed, the second end face 205 fits tightly with the first end face 112. The second hook structure 204 is also provided with a second inclined surface 203 symmetrical to the first inclined surface 108. The angle between the second inclined surface 203 and the horizontal direction is 14.5°. The top of the second hook structure 204 is provided with a protrusion 206. The side of the protrusion 206 is provided with a fixed hook mounting pin hole 201 and a first convex connecting rod mounting pin hole 202.

[0099] The structure of the U-shaped connecting rod 3 is as follows: it includes a protrusion 305, a limit rod mounting pin hole 303 is opened on the side of the protrusion 305, an open structure is provided at the bottom of the protrusion 305, a through groove is opened in the middle of the open structure, corresponding first safety pin holes 304 are opened on both sides of the through groove, a corresponding second pin hole 302 is opened below the first safety pin hole 304, and a corresponding first pin hole 301 is opened below the second pin hole 302.

[0100] The structure of the triangle plate 8 is as follows: it includes a triangle plate body 804 in the shape of a triangle, and a fifth pin hole 801, a second convex connecting rod mounting pin hole 802 and a second safety pin hole 803 are respectively opened at the three inner corners of the side of the triangle plate body 804.

[0101] The protrusion 206 of the movable hook 2 is fitted with the second groove 110 of the fixed hook 1.

[0102] The fixed hook mounting pin hole 201 and the movable hook mounting pin hole 103 are connected by a pin, and the first convex connecting rod mounting pin hole 202 and the first pin hole 301 are connected by a pin.

[0103] The triangular plate 8 is installed by cooperating with the fixed hook 1 through the first groove 109, and the triangular plate 8 is installed by cooperating with the convex connecting rod 3 through the through groove of the convex connecting rod 3.

[0104] The fifth pin hole 801 is connected to the triangular plate mounting pin hole 104 by a pin engagement, and the second convex connecting rod mounting pin hole 802 is connected to the second pin hole 302 by a pin engagement.

[0105] When the fixed hook 1 and the movable hook 2 are closed, the first safety pin hole 304 and the second safety pin hole 803 lock the four-bar linkage mechanism by inserting a safety pin.

[0106] The first limiting rod 4 has a first limiting groove 402 on its side that mates with the limiting shaft 102, and the second limiting rod 5 has a second limiting groove 502 that mates with the limiting shaft 102. One end of the first limiting rod 4 has a third pin hole 401, and one end of the second limiting rod 5 has a fourth pin hole 501. The third pin hole 401 and the fourth pin hole 501 are installed in conjunction with the limiting rod mounting pin hole 303 via a pin shaft, thereby rotatably connecting with the U-shaped connecting rod 3. The other end of the first limiting rod 4 has a first connecting hole 403, and the other end of the second limiting rod 5 has a second connecting hole 503. Short shafts are provided on both sides of the connecting rod 6. The short shafts on the sides of the connecting rod 6 pass through the first connecting hole 403 and the second connecting hole 503 respectively and are fixed to the two limiting rods.

[0107] The drive mechanism 9 has the following structure: it includes a motor 901, the output end of which is connected to a T-shaped block 902. The T-shaped block 902 constrains the first limiting rod 4 and the second limiting rod 5 to move downward. The height of the T-shaped block 902 matches the height of the first limiting rod 4 and the second limiting rod 5. When the limiting shaft 102 enters the first limiting groove 402 and the second limiting groove 502, the T-shaped block 902 is just at the starting position.

[0108] The drive mechanism 9 has the following structure: it includes a motor 901, the output end of which is connected to a T-shaped block 902. The T-shaped block 902 constrains the first limiting rod 4 and the second limiting rod 5 to move downwards. The working process of this invention is as follows:

[0109] Preparation: Securely install the load release device onto the lifting equipment through the mounting hole 101, and retract the T-block 902 back to the starting position;

[0110] The operator lifts the first limit rod 4 and the second limit rod 5, causing the first limit groove 402 and the second limit groove 502 to disengage from the limit shaft 102, and pushes the first limit rod 4 and the second limit rod 5 forward to open the movable grab hook 2;

[0111] By lowering the load release device through the lifting equipment, the load-bearing shaft pin of the load 10 enters the fixed grab hook 1. At this time, the first limit rod 4 and the second limit rod 5 are pulled back, so that the limit shaft 102 is re-engaged into the first limit groove 402 and the second limit groove 502, and the moving grab hook 2 and the fixed grab hook 1 are closed.

[0112] Insert the safety pin into the first safety pin hole 304 and the second safety pin hole 803. A pull rope is connected to the safety pin.

[0113] The load release device and load 10 are lifted by the lifting equipment. After reaching the designated height, the safety pin is pulled out by the pull rope on the safety pin.

[0114] Release load 10. According to the release command, start motor 901. Motor 901 drives T-block 902 to move upward and push the first limit rod 4 and the second limit rod 5 to lift upward until the first limit groove 402 and the second limit groove 502 are separated from the limit shaft 102. At this time, due to the gravity of load 10, the moving hook 2 rotates to release load 10, and load 10 performs free fall motion.

[0115] This invention provides a reasonable design method for the inclined surface of the gripper hook, which enables the gripper hook to generate a rotational torque under the gravity of the load 10. Therefore, it is not necessary to manually push the limit rod forward to open the movable gripper hook 2 when releasing the load 10. The movable gripper hook 2 can open and release the load 10 by itself under the action of the rotational torque. The large load release device provided by this invention has a reasonable and reliable structure. It provides double safety protection through the limit shaft 102 and the safety pin hole, protecting the safety of the workpiece and personnel.

[0116] The above description is an explanation of the present invention and not a limitation thereof. The scope of the present invention is defined by the claims. Within the scope of protection of the present invention, any form of modification may be made.

Claims

1. A design method for a large load release device, characterized in that: The four-bar linkage consists of a fixed hook (1), a movable hook (2), a convex connecting rod (3), and a triangular plate (8). The fixed hook (1) and the movable hook (2) are rotatably connected by a rotating pin. The four-bar linkage bears the load (10). To make the angles of the force-bearing surfaces of the fixed hook (1) and the movable hook (2) symmetrical, in order to ensure that the movable hook (2) can open automatically under the gravity of the load (10), the angles of the first inclined surface (108) set on the fixed hook (1) and the second inclined surface (203) set on the movable hook (2) are designed. Force analysis is performed on the contact surface between the moving hook (2) and the load (10), i.e., the second inclined plane (203): Let the angle between the second inclined plane (203) and the horizontal direction be α. Then the second inclined plane (203) needs to bear the gravity F of the load (10) perpendicular to the horizontal direction. The gravity F is decomposed into F1, F2 and F3. Wherein, F1 represents the normal force borne by the force-bearing surface of the moving hook (2), and the direction of F1 is perpendicular to the second inclined plane (203). F1 is expressed by the following formula: F1=F / cosα(1) F2 represents the force that causes the movable grab (2) to rotate. The direction of F2 is perpendicular to the lever arm of the torque of the movable grab (2). F2 is expressed by the following formula: F2 = F1·sin(α-α1)(2) In the formula, α1 represents the angle between the lever arm of the rotational torque of the moving grab hook (2) and the vertical direction; F3 represents the frictional force F3 that hinders the rotation of the moving hook (2). The direction of F3 is parallel to the second inclined plane (203), and F3 is expressed by the following formula: F3 = µ·F1 (3) In the formula, µ represents the friction coefficient. The fixed gripper (1) and the moving gripper (2) are made of 65Mn spring steel, and the connecting pin is made of 40Cr alloy steel. The friction coefficient µ is 0.

15. In the design calculations, to ensure that the moving gripper (2) can be released, the following formula needs to be satisfied: F2·L-F3·cos(α-α1)·L-µ·F·R≥0(4) In the formula, L represents the lever arm length of the rotational torque of the moving hook (2), and R represents the radius of the rotating pin that rotatably connects the fixed hook (1) and the moving hook (2), R=25mm; Simplifying, we get: sin(α-α1)·L / cosα-µ·cos(α-α1)·L / cosα-µ·R≥0(5) Since the angles of the force-bearing surfaces of the fixed hook (1) and the movable hook (2) are symmetrical, the angle between the first inclined plane (108) and the horizontal direction is 180°-α.

2. The design method of a large load release device as described in claim 1, characterized in that: Increasing the angle between the second inclined plane (203) and the horizontal direction to α or decreasing the angle α1 between the lever arm of the torque that causes the moving hook (2) to rotate and the vertical direction can both increase the force F2 that causes the moving hook (2) to rotate.

3. The design method of a large load release device as described in claim 1, characterized in that: The large load release device used includes a first limiting rod (4) and a second limiting rod (5) rotatably connected to the U-shaped connecting rod (3) in the four-bar linkage. The first limiting rod (4) and the second limiting rod (5) are installed on the outer side of the fixed hook (1) through the connecting rod (6). A through hole is provided in the middle of the connecting rod (6). A buffer rod (7) is installed on the side of the fixed hook (1). The buffer rod (7) passes through the through hole in the middle of the connecting rod (6). A drive mechanism (9) is also installed on the side end of the fixed hook (1). The output end of the drive mechanism (9) corresponds to the first limiting rod (4) and the second limiting rod (5). The drive mechanism (9) pushes the first limiting rod (4) and the second limiting rod (5) to lift upward. The fixed gripping hook (1), the movable gripping hook (2), the convex connecting rod (3) and the triangular plate (8) are all integral structures; The structure of the fixed gripping hook (1) is as follows: it includes a fixed gripping hook body (111), the side end of the fixed gripping hook body (111) is provided with a first groove (109) and a second groove (110), the inner two sides of the first groove (109) are provided with corresponding triangular plate mounting pin holes (104), the inner two sides of the second groove (110) are provided with corresponding movable gripping hook mounting pin holes (103), the lower part of the second groove (110) is provided with a first hook-shaped structure (113), the first hook-shaped structure (113) is provided with a first inclined surface (108), the first inclined surface (108) is provided with a first inclined surface (109) and a second inclined surface (109) is provided with a first inclined surface (109) and a third inclined surface (109) is provided with a second inclined surface (109) and a third inclined surface (109) and a fourth inclined surface (109) and a fifth inclined surface (109) and a sixth inclined surface (109) and a seventh ... 8) The angle with the horizontal direction is 165.5°. The first hook structure (113) is also provided with a first end face (112) that cooperates with the moving hook (2). The other side of the fixed hook body (111) is provided with a second mounting plate (106) and a third mounting plate (107) for installing the drive mechanism (9). A first mounting plate (105) for installing the buffer rod (7) is provided above the second mounting plate (106). Limiting shafts (102) are provided on both sides of the fixed hook body (111). A mounting hole (101) is provided above the limiting shaft (102). The structure of the movable grab hook (2) is as follows: it includes a second hook structure (204) corresponding to the first hook structure (113). The second hook structure (204) is provided with a second end face (205). When the movable grab hook (2) is closed, the second end face (205) fits tightly with the first end face (112). The second hook structure (204) is also provided with a second inclined surface (203) symmetrical to the first inclined surface (108). The angle between the second inclined surface (203) and the horizontal direction is 14.5°. The top of the second hook structure (204) is provided with a protrusion (206). The side of the protrusion (206) is provided with a fixed grab hook mounting pin hole (201) and a first convex connecting rod mounting pin hole (202). The structure of the convex connecting rod (3) is as follows: it includes a protrusion (305), the side of the protrusion (305) is provided with a limit rod mounting pin hole (303), the bottom of the protrusion (305) is provided with an open structure, the middle of the open structure is provided with a through groove, the two sides of the through groove are provided with corresponding first safety pin holes (304), the lower part of the first safety pin hole (304) is provided with a corresponding second pin hole (302), and the lower part of the second pin hole (302) is provided with a corresponding first pin hole (301). The structure of the triangular plate (8) is as follows: it includes a triangular plate body (804) in the shape of a triangle, and the three inner corners of the side of the triangular plate body (804) are respectively provided with a fifth pin hole (801), a second convex connecting rod mounting pin hole (802) and a second safety pin hole (803). When the fixed hook (1) and the movable hook (2) are closed, the first safety pin hole (304) and the second safety pin hole (803) lock the four-bar linkage by inserting the safety pin shaft.

4. The design method of a large load release device as described in claim 3, characterized in that: The protrusion (206) of the movable grab hook (2) is fitted with the second groove (110) of the fixed grab hook (1).

5. The design method of a large load release device as described in claim 3, characterized in that: The fixed hook mounting pin hole (201) and the movable hook mounting pin hole (103) are connected by a pin, and the first convex connecting rod mounting pin hole (202) and the first pin hole (301) are connected by a pin.

6. The design method of a large load release device as described in claim 3, characterized in that: The triangular plate (8) is installed in conjunction with the fixed hook (1) through the first groove (109), and the triangular plate (8) is installed in conjunction with the convex connecting rod (3) through the through groove of the convex connecting rod (3).

7. The design method of a large load release device as described in claim 3, characterized in that: The fifth pin hole (801) is connected to the triangular plate mounting pin hole (104) by a pin engagement, and the second convex connecting rod mounting pin hole (802) is connected to the second pin hole (302) by a pin engagement.

8. The design method of a large load release device as described in claim 3, characterized in that: The first limiting rod (4) has a first limiting groove (402) that cooperates with the limiting shaft (102) on its side, and the second limiting rod (5) has a second limiting groove (502) that cooperates with the limiting shaft (102).

9. The design method of a large load release device as described in claim 3, characterized in that: The structure of the drive mechanism (9) is as follows: it includes a motor (901), the output end of the motor (901) is connected to a T-block (902), and the T-block (902) constrains the first limiting rod (4) and the second limiting rod (5) to move downward.

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