Leather strength detection device and use method

Abstract

The invention relates to the technical field of leather detection, in particular to a leather strength detection device and a using method.The leather strength detection device comprises a detector and an ejector pin which is arranged on the detector and used for detecting the leather strength in a puncturing mode, and two external air supply positioning cylinders are fixedly arranged on one side of the detector in an up-down opposite mode; a plurality of fixing rings with the diameters decreasing progressively are coaxially arranged in the positioning cylinder in a sleeved mode and used for pressing and fixing leather, and the fixing ring on the outermost side is connected with the remaining fixing rings through a support. According to the leather strength detection device and the use method, through a mechanism of forming negative pressure through pressing and fixing of an air pressure pushing combination body and air exhaust, broken holes invisible to naked eyes of leather can be automatically recognized, stable negative pressure is formed if no broken holes exist, negative pressure fails if broken holes exist, meanwhile, fixing rings which are not completely in contact with the leather can be automatically disconnected according to the negative pressure state, and the leather strength is detected. Only an effective pressing and fixing area is reserved, puncture detection deviation caused by hidden defects or incomplete pressing and fixing is avoided, and it is guaranteed that the detection result is accurate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of leather detection, in particular to a leather strength detection device and a use method thereof. BACKGROUND

[0002] In the process of leather production and quality control, leather strength (especially puncture strength) is a key indicator for evaluating its durability and applicability. The existing leather strength detection equipment has many deficiencies in actual application: Firstly, most of the equipment relies on manual adjustment of the pressure fixing mechanism to fix the leather, which is difficult to ensure the comprehensiveness and stability of the pressure fixing area. If the edge of the leather is not completely fixed or there is a hole that cannot be seen by the naked eye, it is easy to cause the leather to shift or the detection result to be distorted during puncture detection; secondly, there is a lack of pre-detection mechanism for hidden defects of leather (such as small holes). If the leather with defects is directly subjected to puncture detection, the detection data will lose reference value, and it is necessary to re-sample and detect, which increases the operation cost and time; thirdly, the safety and automation degree of the detection process is low. Manual misoperation (such as starting puncture without completing pressure fixing) can easily lead to detection errors, and manual adjustment of parameters is required frequently to adapt to different specifications of leather, which is tedious and inefficient.

[0003] In view of this, we propose a leather strength detection device and a use method thereof. SUMMARY

[0004] The purpose of the present application is to provide a leather strength detection device and a use method thereof to solve the problems of unstable pressure fixing, lack of hidden defect pre-detection, low automation and safety of the existing detection equipment in the background art. To achieve the above purpose, the present application provides the following technical scheme: a leather strength detection device, comprising a detector and a thimble arranged thereon for detecting the strength of the leather, and two positioning cylinders arranged on one side of the detector in an upward and downward direction, the positioning cylinders are externally supplied with gas, a plurality of fixed rings with decreasing diameters are coaxially arranged in the positioning cylinders for fixing the leather, the outermost fixed ring is connected to the remaining fixed rings through a support; a plurality of movable rings with decreasing diameters are coaxially arranged in the positioning cylinders for embedding between the fixed rings to form a solid structure, the movable rings are fixedly connected through a sliding frame, a sliding groove is arranged in the positioning cylinder for the movement of the sliding frame and the movable rings, and when the positioning cylinder is filled with gas, the gas pressure drives the movable rings to move and combine with the fixed rings, and then drives the combined body to slide out to fix the leather; a clamping groove is formed on the positioning cylinder, a spring latch is arranged on the outer wall of the outermost fixed ring, and after the fixed ring fixes the leather, the spring latch is inserted into the clamping groove to lock the outermost fixed ring; a reset spring is arranged in the sliding groove for driving the sliding frame and the movable rings to reset, and when the movable rings are reset, a negative pressure is generated in the area between the fixed rings; The thimble is located at the center of the combined body.

[0005] Preferably, a connecting pin is provided on the inner fixing ring, and the connecting pin is inserted into the bracket. An annular groove is provided in the bracket. A retaining ring is movably embedded at the insertion end of the connecting pin, and the retaining ring is embedded in the annular groove to lock the connecting pin and the bracket. The fixing ring and connecting pin have vent holes that communicate with the negative pressure area and are used to control the air vents of the retaining ring.

[0006] Preferably, a needle tip is movably inserted into the end of the ejector pin, and the needle tip and ejector pin are pushed apart by a top spring. A groove is provided on the side surface of the needle tip, and a limiting piece is movably embedded in the groove. The needle tip and ejector pin are designed as hollow structures that allow air to pass through the groove. When the negative pressure in the negative pressure area pulls out the limiting piece, the limiting piece locks the telescopic function between the pin head and the ejector pin.

[0007] Preferably, a sealing gasket is fitted onto the inner wall of the fixed ring, and the sealing gasket is located in the contact area between the movable ring and the fixed ring.

[0008] Preferably, the pressing surface of the fixing ring is bonded with an anti-slip rubber layer, and the surface of the anti-slip rubber layer has several transverse anti-slip grooves.

[0009] Preferably, a displacement sensor is provided on the side wall of the ejector pin, and the displacement sensor is electrically connected to the control system of the detector.

[0010] Preferably, the positioning cylinder is equipped with a pressure gauge, and the pressure gauge is connected to the inside of the positioning cylinder.

[0011] A method of using a leather strength testing device includes the following steps: S1. Lay the leather to be tested flat between two positioning cylinders that are positioned vertically opposite each other.

[0012] S2. The external air supply system injects air pressure into the two positioning cylinders. The air pressure acts on the end face of the movable ring, pushing the movable ring to move along the slide groove towards the fixed ring. This causes several movable rings with decreasing diameters to be precisely embedded between the fixed rings of corresponding diameters, forming a solid compression structure. As the air pressure continues to increase, it pushes the entire "fixed ring-movable ring" assembly to slide out of the positioning cylinder until the upper and lower assemblies contact the upper and lower surfaces of the leather and are relatively squeezed, thus achieving the initial compression of the leather.

[0013] S3. When the compressive force of the assembly on the leather reaches the preset value, the spring pin on the outermost fixing ring pops out under its own elastic force and inserts into the slot opened on the positioning cylinder, thus locking the outermost fixing ring and preventing the assembly from shifting in subsequent operations. Then, the air injection is stopped and the positioning cylinder air extraction system is started. During the air extraction process, in conjunction with the return spring, the slide and movable ring are driven to return to the inside of the positioning cylinder along the slide groove. The movable ring is pulled out from between the fixing rings, so that the area between the fixing rings forms a closed space. If the leather has no holes that are not visible to the naked eye, a stable negative pressure will be formed in the closed space. The amount of movable ring reset is reduced due to the resistance of the negative pressure. If there are holes in the leather, the closed space cannot form a negative pressure, and the movable ring will return to its initial position under the action of the return spring, thus completing the preliminary detection of holes in the leather.

[0014] S4. After a stable negative pressure is formed between the fixing rings, the negative pressure draws the retaining ring, which is movably embedded in the connecting pin insertion end, out of the ring groove through the air hole, thus disconnecting the connection between the inner fixing ring and the outermost fixing ring. If the edge of the leather cannot fully contact the inner fixing ring (i.e., the area cannot form effective compression), there is no negative pressure in the corresponding fixing ring and connecting pin, and the retaining ring remains embedded in the ring groove. The inner fixing ring and the outermost fixing ring are still connected. At this time, the positioning cylinder continues to pump air, and the unconnected inner fixing ring is drawn up under the action of negative pressure. Only the fixing ring that is in full contact with the leather continues to be compressed, automatically planning the maximum effective compression path of the leather.

[0015] S5. When a stable negative pressure is formed between the fixed rings, the negative pressure will draw out the limiting piece in the groove, causing the limiting piece to engage between the needle and the ejector pin, locking the telescopic function of both and forming a rigid connection. At this time, the puncture detection program of the detector is started. The ejector pin drives the needle to rise synchronously and puncture the central pressure area of ​​the leather to complete the leather strength test. If a stable negative pressure is not formed (such as if the leather has holes or the pressure is not complete), there is no negative pressure in the groove, the limiting piece remains in the groove, and the needle and ejector pin are still telescopically connected by the ejector spring. Even if the ejector pin rises, the needle will extend and retract under the action of the ejector spring, making it impossible to puncture the leather and avoid improper operation or incorrect detection.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: In this invention, through the mechanism of "air pressure pushing assembly for compaction - air extraction to form negative pressure", it can automatically identify holes in leather that are not visible to the naked eye (a stable negative pressure is formed when there are no holes, and the negative pressure fails when there are holes). At the same time, it can automatically disconnect the fixing ring connection that is not in complete contact with the leather according to the negative pressure state, leaving only the effective compaction area, avoiding puncture detection deviations caused by hidden defects or incomplete compaction, and ensuring accurate detection results.

[0017] In this invention, negative pressure is used as the key control signal. Only when the leather is properly pressed and free of defects (forming a stable negative pressure) will the negative pressure draw out the limiting plate to lock the rigid connection between the ejector pin and the needle head, enabling the ejector pin to have the puncture function. If the pressing is not qualified or the leather is defective (no negative pressure), the needle head and ejector pin remain in a retractable state, and even if the puncture program is started, it cannot be detected. This completely avoids erroneous detection caused by improper operation or accidental triggering from the structure.

[0018] In this invention, no complex manual intervention is required. The device can automatically complete the entire process of "compression-defect pre-inspection-effective compression path planning-puncture detection". Furthermore, through the structure of spring pin locking the fixed ring and reset spring assisting the movable ring to reset, the stable connection of each link is ensured. This not only reduces the cost of manual operation, but also improves the adaptability to the detection of different specifications of leather, taking into account both detection efficiency and reliability. Attached Figure Description

[0019] Figure 1 This is a three-dimensional structural diagram of the present invention; Figure 2 This is an exploded view of the positioning cylinder, fixed ring, and movable ring of the present invention; Figure 3 This is a bottom view of the three-dimensional structure of the fixed ring and the movable ring of the present invention; Figure 4 This is a three-dimensional cross-sectional view of the positioning cylinder, fixing ring, movable ring, and ejector pin of the present invention. Figure 1 ; Figure 5 For the present invention Figure 4 Enlarged view of point A in the middle; Figure 6 For the present invention Figure 4 Enlarged view of point B in the middle; Figure 7 This is a three-dimensional cross-sectional view of the positioning cylinder, fixing ring, movable ring, and ejector pin of the present invention. Figure 2 ; Figure 8 This is an exploded view of the fixing ring of the present invention; Figure 9 For the present invention Figure 8 Enlarged view of point C in the middle; Figure 10 This is a three-dimensional structural cross-sectional view of the movable ring of the present invention; Figure 11 This is an exploded view of the ejector pin and needle tip of the present invention.

[0020] In the diagram: 1. Detector; 2. Ejector pin; 3. Positioning cylinder; 4. Fixing ring; 5. Bracket; 6. Movable ring; 7. Slide; 8. Slide groove; 9. Slot; 10. Spring pin; 11. Return spring; 12. Connecting pin; 13. Ring groove; 14. Snap ring; 15. Air hole; 16. Needle; 17. Top spring; 18. Embedded groove; 19. Limiting piece. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] Please see Figures 1 to 11 The present invention provides a technical solution: a leather strength testing device, including a testing instrument 1 and a pin 2 set on it for puncturing and testing the leather strength. The axis of the pin 2 is arranged in a vertical direction, and the pin 2 is connected to the power output end of the testing instrument 1. The vertical lifting action can be achieved by controlling the testing instrument 1 to complete the puncture strength test of the leather.

[0023] Two externally supplied positioning cylinders 3 are fixedly installed on the side of the detector 1 near the ejector pin 2, facing each other vertically. The axes of the two positioning cylinders 3 are collinear and coincide with the axis of the ejector pin 2, ensuring that the area for subsequent pressing of the leather corresponds precisely to the puncture area of ​​the ejector pin 2. One end of the positioning cylinder 3 is an open structure, and the opening faces the direction in which the leather is placed. The other end of the positioning cylinder 3 is connected to the external air supply system and the air extraction system through an air pipe, which can realize the switching control of inflation and air extraction.

[0024] The positioning cylinder 3 is coaxially fitted with several fixing rings 4 of decreasing diameter. The fixing rings 4 are spaced apart along the axis of the positioning cylinder 3, and the outer wall of the fixing ring 4 and the inner wall of the positioning cylinder 3 are reserved with a gap for the movable ring 6 to move. The end of the fixing ring 4 away from the opening of the positioning cylinder 3 is provided with an initial limiting structure between it and the inner wall of the positioning cylinder 3 to prevent the fixing ring 4 from moving randomly when no air is supplied. The fixing ring 4 is used to press the leather to prevent the leather from shifting during puncture. The outermost fixing ring 4 is fixedly connected to the remaining fixing rings 4 through several brackets 5 evenly distributed along the circumference to ensure that the fixing rings 4 form a stable overall structure.

[0025] The positioning cylinder 3 is also coaxially fitted with several movable rings 6 with decreasing diameters. The number of movable rings 6 is the same as the number of fixed rings 4, and the inner diameter and outer diameter of each movable ring 6 are matched with the inner diameter and outer diameter of the corresponding fixed ring 4, respectively. They are used to embed into the gap between two adjacent fixed rings 4, so that the fixed rings 4 and movable rings 6 combine to form a complete solid compression structure, thereby improving the stress stability during compression.

[0026] The movable rings 6 are fixedly connected by a slide 7. The end of the slide 7 extends to the inner wall of the positioning cylinder 3. The positioning cylinder 3 has a slide groove 8 that is adapted to the slide 7. The slide groove 8 is set along the axial direction of the positioning cylinder 3 to allow the slide 7 and movable rings 6 to move stably along the axial direction. The slide groove 8 is connected to the air supply area inside the positioning cylinder 3 to ensure that the air pressure can directly act on the end faces of the slide 7 and movable rings 6.

[0027] When air is injected into the positioning cylinder 3, the air pressure pushes the slide 7 to move the movable ring 6 along the slide groove 8 toward the fixed ring 4, so that several movable rings 6 are precisely embedded in the gaps between the corresponding fixed rings 4, and are combined to form a solid compression structure.

[0028] As the air pressure inside the positioning cylinder 3 continues to increase, the thrust of the air pressure on the solid compression structure is greater than the initial limiting force of the fixed ring 4, pushing the entire "fixed ring 4-movable ring 6" assembly to slide out from the opening end of the positioning cylinder 3 until the upper and lower assemblies respectively contact the upper and lower surfaces of the leather and generate preset pressure, thus achieving the initial compression of the leather.

[0029] The side wall of the positioning cylinder 3 is provided with several slots 9 spaced apart along the axial direction. The position of the slots 9 corresponds to the movement path of the outermost fixing ring 4. A spring pin 10 is provided on the outer wall of the outermost fixing ring 4. The spring pin 10 includes a pin body, a return spring and a limiting block. The return spring is sleeved on the outside of the pin body, one end is fixedly connected to the outer wall of the fixing ring 4, and the other end abuts against the limiting block on the pin body, so that the pin body always has the tendency to pop out in the direction of the slots 9.

[0030] When the "fixed ring 4-movable ring 6" assembly slides out and the pressure on the leather reaches the preset value, the spring pin 10 on the outer wall of the outermost fixed ring 4 aligns with the slot 9 on the positioning cylinder 3. The pin body pops out under the action of the reset spring and inserts into the slot 9, thus locking the outermost fixed ring 4 and preventing the assembly from shifting due to negative pressure during subsequent air extraction, ensuring a stable pressure state.

[0031] A return spring 11 is provided at the end of the slide groove 8 away from the fixed ring 4. One end of the return spring 11 is fixedly connected to the end of the slide groove 8, and the other end abuts against the side of the slide 7 away from the fixed ring 4. In the initial state, the return spring 11 is in a naturally extended state.

[0032] When the positioning cylinder 3 stops injecting air and the air extraction system is activated, the air pressure inside the positioning cylinder 3 decreases. The elastic force of the return spring 11 is greater than the force exerted by the air pressure on the slide 7, which pushes the slide 7 to move the movable ring 6 along the slide groove 8 to the inside of the positioning cylinder 3. The movable ring 6 is gradually pulled out from the gap between the fixed rings 4. At this time, a closed space is formed between the fixed rings 4, the movable ring 6 and the leather.

[0033] As the active ring 6 continues to reset, the volume of the enclosed space gradually increases, the internal air pressure decreases, and negative pressure is formed.

[0034] If the leather has no holes that are not visible to the naked eye and the airtightness of the enclosed space is good, a stable negative pressure will be formed. The negative pressure will generate a reverse pulling force on the movable ring 6, causing the reset amount of the movable ring 6 to be reduced due to the resistance of the negative pressure.

[0035] If there is a hole in the leather, the enclosed space is connected to the outside and cannot form negative pressure. The movable ring 6 returns to its initial position under the action of the return spring 11, thus completing the preliminary detection of the hole in the leather.

[0036] The ejector pin 2 is located at the center of the "fixed ring 4-movable ring 6" assembly, ensuring that the puncture point of the ejector pin 2 is in the center area of ​​the leather's compression, thus preventing the leather edge from lifting up during puncture and affecting the test results.

[0037] In this embodiment, as Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figures 5 to 11 As shown, each inner fixing ring 4 has a connecting pin 12 on its outer wall, and the number of connecting pins 12 corresponds to the number of brackets 5. The brackets 5 have through holes that are adapted to the connecting pins 12, and the end of the connecting pin 12 away from the fixing ring 4 is inserted into the through hole of the bracket 5.

[0038] The inner wall of the through hole of the bracket 5 is provided with an annular groove 13, and the insertion end of the connecting pin 12 is provided with an installation groove. A retaining ring 14 is movably embedded in the installation groove. The retaining ring 14 is an elastic metal ring. In the initial state, part of the structure of the retaining ring 14 is embedded in the annular groove 13, locking the connecting pin 12 and the bracket 5, so that the inner fixing ring 4 and the outermost fixing ring 4 remain relatively fixed.

[0039] The fixed ring 4 and the shaft of the connecting pin 12 are provided with interconnected air holes 15. One end of the air hole 15 is connected to the negative pressure area formed after the fixed ring 4 and the movable ring 6 are reset, and the other end extends to the mounting groove of the connecting pin 12.

[0040] When a stable negative pressure is formed in the negative pressure area, the negative pressure is transmitted to the mounting groove of the connecting pin 12 through the air hole 15, which generates a suction force on the retaining ring 14, causing the elastic retaining ring 14 to deform and disengage from the annular groove 13 of the bracket 5, releasing the locking between the connecting pin 12 and the bracket 5, and causing the inner fixing ring 4 to disconnect from the outermost fixing ring 4.

[0041] If the edge of the leather cannot fully contact the inner fixing ring 4, a closed space cannot be formed between the fixing ring 4 and the leather in that area. There is no negative pressure in the air hole 15 in the corresponding fixing ring 4 and connecting pin 12. The retaining ring 14 remains embedded in the ring groove 13, and the inner fixing ring 4 and the outermost fixing ring 4 are still connected.

[0042] At this time, the positioning cylinder 3 continues to pump air, and the unconnected inner fixing ring 4 is sucked up under the negative pressure. Only the fixing ring 4 that is in full contact with the leather continues to be pressed, and the maximum effective pressing path of the leather is automatically planned.

[0043] In this embodiment, as Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figures 5 to 11 As shown, the end of the ejector pin 2 is provided with a insertion hole, and a needle 16 is movably inserted into the insertion hole. The needle 16 is made of high-strength alloy.

[0044] A top spring 17 is fixedly installed at the bottom of the insertion hole. The other end of the top spring 17 abuts against the tail of the needle 16. In its natural state, the top spring 17 pushes the needle 16 away from the ejector pin 2, so that the needle 16 and the ejector pin 2 are in a retractable connection.

[0045] The side surface of the needle 16 is provided with a groove 18, and a limiting piece 19 is movably embedded in the groove 18. In the initial state, the limiting piece 19 is fully embedded in the groove 18 and does not affect the extension and retraction of the needle 16 and the ejector pin 2.

[0046] Both the needle 16 and the ejector pin 2 are hollow structures. One end of the hollow channel of the ejector pin 2 is connected to the negative pressure area between the fixed ring 4 through an air tube, and the other end extends to the inner wall of the insertion hole and corresponds to the groove 18 of the needle 16. The hollow channel of the needle 16 is connected to the hollow channel of the ejector pin 2 to ensure that the negative pressure in the negative pressure area can be transmitted to the groove 18.

[0047] When a stable negative pressure is formed in the negative pressure area, the negative pressure will draw out the limiting piece 19 in the groove 18. Part of the structure of the limiting piece 19 extends out of the groove 18 and is locked at the inner wall step of the insertion hole of the ejector pin 2, locking the telescopic function between the needle head 16 and the ejector pin 2, so that the two form a rigid connection.

[0048] At this time, the puncture test program of the tester 1 is started. The pin 2 can drive the needle 16 to rise synchronously and perform stable puncture on the central pressing area of ​​the leather to complete the leather strength test.

[0049] If a stable negative pressure is not formed in the negative pressure area, such as if the leather has holes or is not fully compressed, there will be no negative pressure in the groove 18. The limiting piece 19 will remain in the groove 18, and the needle 16 and the ejector pin 2 will still be retractably connected through the ejector spring 17. Even if the ejector pin 2 rises, the needle 16 will retract under the action of the ejector spring 17, making it impossible to puncture the leather and avoiding improper operation or incorrect detection.

[0050] In this embodiment, as Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figures 5 to 11As shown, a sealing gasket is fitted onto the inner wall of the fixed ring 4. The sealing gasket is located in the contact area between the movable ring 6 and the fixed ring 4, which can enhance the sealing between the two, reduce the leakage of air pressure or negative pressure during the movement of the movable ring 6, ensure the stability of air pressure in the positioning cylinder 3, ensure the precise combination of the movable ring 6 and the fixed ring 4, the effective transmission of the clamping force, and the accuracy of negative pressure detection, and avoid the misjudgment of the clamping or hole detection due to air leakage.

[0051] In this embodiment, as Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figures 5 to 11 As shown, the pressing surface of the fixing ring 4 is bonded with an anti-slip rubber layer. The surface of the anti-slip rubber layer has several transverse anti-slip grooves, which can increase the friction between the fixing ring 4 and the leather. This can effectively prevent the leather from slipping during the pressing process or during puncture testing, ensuring that the leather is always in the preset testing position, ensuring the stability of the pressing and the accuracy of the puncture test, and avoiding the impact of leather displacement on the reliability of the test results.

[0052] In this embodiment, as Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figures 5 to 11 As shown, a displacement sensor is provided on the side wall of the needle 2. The displacement sensor is electrically connected to the control system of the detector 1. It can monitor the displacement change data of the needle 2 when piercing the leather in real time and transmit the data to the control system. This facilitates the analysis of the resistance change of the leather when it is pierced by the displacement, and helps to quantitatively evaluate the strength characteristics of the leather, making the test results more objective and quantifiable.

[0053] In this embodiment, as Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figures 5 to 11 Figure 1 Figure 2 Figure 3 Figure 4 Figures 5 to 11 As shown, a pressure gauge is installed on the positioning cylinder 3. The pressure gauge is connected to the inside of the positioning cylinder 3 and can intuitively display the real-time air pressure value inside the positioning cylinder 3. This allows the operator to accurately adjust the injection pressure according to the thickness, material and other characteristics of the leather to be tested. This can avoid damage to the leather due to excessive pressure, and prevent insufficient pressure from causing loose compaction. It ensures that the compaction effect meets the testing requirements, and improves the convenience of operation and the adaptability of testing.

[0054] A method of using a leather strength testing device includes the following steps: S1. Lay the leather to be tested flat between two positioning cylinders 3 that are positioned vertically opposite each other.

[0055] S2. The external air supply system injects air pressure into the two positioning cylinders 3. The air pressure acts on the end face of the movable ring 6, pushing the movable ring 6 to move along the slide groove 8 towards the fixed ring 4, so that several movable rings 6 with decreasing diameters are precisely embedded between the fixed rings 4 of corresponding diameters, forming a solid compression structure. As the air pressure continues to increase, it pushes the entire "fixed ring 4-movable ring 6" assembly to slide out of the positioning cylinder 3 until the upper and lower assemblies contact the upper and lower surfaces of the leather respectively and squeeze them relative to each other, thus achieving the initial compression of the leather.

[0056] S3. When the compressive force of the assembly on the leather reaches the preset value, the spring pin 10 on the outer wall of the outermost fixing ring 4 pops out under its own elastic force and inserts into the slot 9 opened on the positioning cylinder 3, thus locking the outermost fixing ring 4 and preventing the assembly from shifting in subsequent operations. Then, the air injection is stopped and the air extraction system of the positioning cylinder 3 is started. During the air extraction process, in conjunction with the return spring 11, the slide 7 and the movable ring 6 are driven to return to the inside of the positioning cylinder 3 along the slide groove 8. The movable ring 6 is pulled out from between the fixing rings 4, so that the area between the fixing rings 4 forms a closed space. If the leather has no holes that are not visible to the naked eye, a stable negative pressure will be formed in the closed space. The amount of the movable ring 6 is reduced due to the resistance of the negative pressure. If there are holes in the leather, the closed space cannot form a negative pressure, and the movable ring 6 will return to the initial position under the action of the return spring 11, thus completing the preliminary detection of holes in the leather.

[0057] S4. After a stable negative pressure is formed between the fixing rings 4, the negative pressure draws the retaining ring 14, which is movably embedded in the insertion end of the connecting pin 12, out of the ring groove 13 through the air hole 15, so that the connection between the inner fixing ring 4 and the outermost fixing ring 4 is broken. If the edge of the leather cannot fully contact the inner fixing ring 4, that is, the area cannot form effective compression, then there is no negative pressure in the fixing ring 4 and the connecting pin 12 at the corresponding position, the retaining ring 14 remains embedded in the ring groove 13, and the inner fixing ring 4 and the outermost fixing ring 4 are still connected. At this time, the positioning cylinder 3 continues to pump air, and the unconnected inner fixing ring 4 is sucked up under the action of negative pressure, leaving only the fixing ring 4 that is in full contact with the leather to continue to be compressed, automatically planning the maximum effective compression path of the leather.

[0058] S5. When a stable negative pressure is formed between the fixed rings 4, the negative pressure will draw out the limiting piece 19 in the groove 18, so that the limiting piece 19 is locked between the needle 16 and the ejector pin 2, locking the telescopic function of the two and forming a rigid connection. At this time, the puncture detection program of the detector 1 is started. The ejector pin 2 drives the needle 16 to rise synchronously and puncture the central pressure area of ​​the leather to complete the leather strength test. If a stable negative pressure is not formed, such as if the leather has holes or the pressure is not complete, there is no negative pressure in the groove 18, the limiting piece 19 remains in the groove 18, and the needle 16 and the ejector pin 2 are still telescopically connected by the top spring 17. Even if the ejector pin 2 rises, the needle 16 will extend and retract under the action of the top spring 17, and cannot puncture the leather to avoid improper operation or incorrect detection.

[0059] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A leather strength testing device, comprising a testing instrument (1) and a puncture needle (2) on the testing instrument (1) for puncturing and testing the strength of leather, characterized in that: The detector (1) has two externally supplied positioning cylinders (3) fixedly installed on one side, facing each other vertically. The positioning cylinder (3) is coaxially fitted with several fixing rings (4) of decreasing diameter for pressing and securing leather. The outermost fixing ring (4) is connected to the other fixing rings (4) through a bracket (5). The positioning cylinder (3) is also coaxially fitted with several movable rings (6) of decreasing diameter, which are used to embed between the fixed rings (4) to form a solid structure. The movable rings (6) are fixedly connected by a slide (7). The positioning cylinder (3) is provided with a slide groove (8) for the slide (7) and the movable rings (6) to move. When the positioning cylinder (3) is filled with air, the air pressure pushes the movable rings (6) to move and combine with the fixed rings (4), and pushes the combination to slide out of the pressed leather. The positioning cylinder (3) has a slot (9) and the outermost fixing ring (4) has a spring pin (10) on its outer wall. After the fixing ring (4) presses the leather, the spring pin (10) is inserted into the slot (9) to lock the outermost fixing ring (4). The slide groove (8) is provided with a reset spring (11) to push the slide (7) and the movable ring (6) to reset. When the movable ring (6) is reset, a negative pressure is generated in the area between the fixed rings (4).

2. The leather strength testing device according to claim 1, characterized in that: The inner fixing ring (4) is provided with a connecting pin (12), the connecting pin (12) is inserted into the bracket (5), the bracket (5) is provided with an annular groove (13), the insertion end of the connecting pin (12) is movably fitted with a retaining ring (14), the retaining ring (14) is embedded in the annular groove (13) to lock the connecting pin (12) and the bracket (5); The fixing ring (4) and connecting pin (12) are provided with air holes (15) that communicate with the negative pressure area and are used to control the retaining ring (14).

3. The leather strength testing device according to claim 2, characterized in that: The end of the ejector pin (2) is movably connected to a needle head (16), and the needle head (16) and the ejector pin (2) are pushed apart by a top spring (17). A groove (18) is provided on the side surface of the needle head (16), and a limiting piece (19) is movably embedded in the groove (18). The needle head (16) and the ejector pin (2) are designed as a hollow structure that allows air to pass through the groove (18). When the negative pressure in the negative pressure area draws out the limiting piece (19), the limiting piece (19) locks the extension and retraction function of the needle (16) and the ejector pin (2).

4. The leather strength testing device according to claim 3, characterized in that: The inner wall of the fixed ring (4) is fitted with a sealing gasket, which is located in the contact area between the movable ring (6) and the fixed ring (4).

5. The leather strength testing device according to claim 4, characterized in that: The pressing surface of the fixing ring (4) is bonded with an anti-slip rubber layer, and the surface of the anti-slip rubber layer is provided with several transverse anti-slip patterns.

6. The leather strength testing device according to claim 5, characterized in that: The side wall of the ejector pin (2) is provided with a displacement sensor, which is electrically connected to the control system of the detector (1).

7. The leather strength testing device according to claim 6, characterized in that: The positioning cylinder (3) is equipped with a pressure gauge, which is connected to the inside of the positioning cylinder (3).

8. A method of using a leather strength testing device, comprising using the leather strength testing device as described in claim 7, characterized in that, Includes the following steps: S1. Lay the leather to be tested flat between two positioning cylinders (3) that are positioned vertically opposite each other; S2. The external air supply system injects air into the positioning cylinder (3). The air pressure pushes the movable ring (6) to move and embed into the fixed ring (4) to form a solid compression structure. Continuous air injection pushes the assembly to slide out. The upper and lower assemblies squeeze the leather to achieve initial compression. S3. When the compressive force reaches the preset value, the spring pin (10) is inserted into the slot (9) to lock the outermost fixed ring (4), the air injection is stopped and the air extraction system is started. With the help of the reset spring (11), the movable ring (6) is reset, and a closed space is formed between the fixed rings (4). The initial detection of leather hole is completed by whether negative pressure is generated. S4. After a stable negative pressure is formed, the negative pressure draws out the retaining ring (14) through the air hole (15), causing the inner side to break the connection with the outermost fixing ring (4). The fixing ring (4) that is not in complete contact with the leather is drawn up under the action of negative pressure, and the maximum effective pressing path is planned. S5. The stable negative pressure suction limit plate (19) locks the needle (16) and the ejector pin (2) and starts the puncture procedure to complete the test; when no negative pressure is formed, the needle (16) and the ejector pin (2) remain in a retractable connection to avoid incorrect detection.

Images