Corrugated board ring crush compression strength detection device

Abstract

The invention discloses a corrugated board ring crush compression strength detection device, and belongs to the technical field of physical properties of paper products. Comprising a case, guide columns, an upper cross beam, a test platform capable of vertically lifting and an upper pressure head located above the platform, the detection device also comprises a centering mechanism, and the centering mechanism comprises a clamping assembly, a synchronous rod which synchronously ascends and descends along with the test platform, and an angle pin block which is arranged on the synchronous rod. According to the corrugated board ring crush compression strength detection device, by means of kinetic energy generated when the test platform ascends and through mechanical linkage of the angle pin block and the contact wheel, the clamping assemblies are driven to synchronously get close to the center to conduct automatic centering on the test piece before testing, and automatic avoiding and resetting are conducted before the test piece makes contact with the upper pressing head. The device effectively eliminates visual errors existing in manual visual alignment, ensures that the center of a test piece coincides with the force application center of the upper pressure head, avoids the unbalance loading effect caused by eccentric placement, and improves the accuracy of ring crush compression strength detection data.

Description

A device for testing the ring crush strength of corrugated sheets Technical Field

[0001] This invention relates to the field of physical properties of paper products, and in particular to a device for testing the ring crush strength of corrugated boards. Background Technology

[0002] In the paper and packaging industry, the ring crush strength of corrugated base paper is a key indicator for evaluating the paper's compressive strength and the final stacking strength of cartons. When conducting a ring crush strength test, according to relevant standards, the base paper to be tested is first cut and wound into a ring shape, placed in a special sample holder consisting of a central disc and a mother disc (base), and kept vertically fixed. Then, the assembled sample holder is placed on the lower platen of a compression testing machine, and the machine is started to move the upper platen vertically downwards, applying axial pressure to the sample until it crushes, thereby obtaining its strength data.

[0003] However, in actual use, the positioning of the sample holder on the lower pressure plate in existing testing devices mainly relies on the operator manually centering it by visually observing the concentric circle scale on the surface of the lower pressure plate. This traditional method has defects: First, the centering accuracy is affected by human factors. Due to visual errors in human judgment, it is difficult to ensure that the geometric center of the sample holder coincides with the force application center axis of the upper pressure plate. Once the sample holder is placed eccentrically, the upper pressure plate will generate an eccentric torque when pressing down to contact the sample, resulting in uneven force on various parts of the sample ring. This abnormal failure mode will cause the final measured strength value to be lower than the true performance of the sample, thus misleading the judgment of product quality.

[0004] It should be noted that the information disclosed in this background section is only for understanding the background technology of this application concept, and therefore may include information that does not constitute prior art. Summary of the Invention

[0005] This invention provides a corrugated board ring crush strength testing device to solve the technical problem that existing visual alignment is prone to eccentricity, resulting in uneven force and distorted and low test data.

[0006] This invention adopts the following technical solution: a corrugated board ring crush strength testing device. It includes a housing with several guide pillars fixedly mounted on its top, and an upper crossbeam fixedly connected between the top ends of the guide pillars; a testing platform, positioned above the housing, capable of vertical lifting and lowering to support the test piece; and an upper pressure head, positioned below the upper crossbeam and directly above the testing platform. The device is characterized in that it further includes a centering mechanism, which includes a clamping assembly; the centering mechanism is configured to utilize the kinetic energy of the rising testing platform to drive the clamping assembly to synchronously move towards the center, so that the center of the test piece coincides with the force application center of the upper pressure head.

[0007] Furthermore, the clamping assembly includes two sets of symmetrically arranged arc-shaped grippers; the side wall of the guide post is provided with an opening groove along the axial direction; the centering mechanism also includes two sets of symmetrically arranged synchronizing rods, one end of which extends through the opening groove into the interior of the guide post and is connected to the component that drives the test platform to rise and fall, so that the synchronizing rod can rise and fall synchronously with the test platform; a slanted pin block is fixedly provided on the side of the rod body outside the guide post of the synchronizing rod.

[0008] Furthermore, the inclined pin block has a triangular plate-like structure with a protruding rounded corner on the side opposite to the synchronizing rod; the inclined pin block forms two inclined surfaces, namely a first inclined surface located above and a second inclined surface located below; the first inclined surface is used to push the arc-shaped gripper inward during the upward movement, and the second inclined surface is used to release the arc-shaped gripper to reset during the continued upward movement.

[0009] Furthermore, the centering mechanism also includes a fixed bracket, which is tightly fixed to the outer wall of the guide post and located above the synchronizing rod; a movable through rod is horizontally slidably passed through the fixed bracket, one end of the movable through rod faces the inclined pin block and is equipped with a contact wheel, the contact wheel being adapted to roll and abut against the first inclined surface and the second inclined surface.

[0010] Furthermore, a step is provided on the rod body located inside the fixed bracket of the movable through rod, and a return spring is sleeved on the movable through rod; the two ends of the return spring abut against the inner wall of the fixed bracket and the step respectively, for applying a pushing force toward the inclined pin block to the movable through rod in the initial state.

[0011] Furthermore, the centering mechanism also includes a telescopic unit for accommodating the relative displacement when the test platform rises; the telescopic unit includes a connecting end horizontally connected to the other end of the movable through rod, and a fixed rod vertically downward connected to the connecting end; a movable sleeve is sleeved on the outside of the fixed rod, and the movable sleeve can slide up and down along the axial direction of the fixed rod; a connecting spring is connected between the end of the fixed rod that extends into the movable sleeve and the bottom end of the inner wall of the movable sleeve.

[0012] Furthermore, the arc-shaped gripper is fixedly installed on the side wall of the movable sleeve rod, and a flexible pad is embedded in the inner side of the central disk of the test piece contacting the arc-shaped gripper to buffer the contact pressure; a contact ball is embedded in the bottom end of the movable sleeve rod. When the test platform moves the test piece upward, the contact ball abuts against the upper surface of the test platform and generates relative sliding and telescopic displacement as the test platform rises.

[0013] Furthermore, a drive motor is installed inside the chassis, and the output end of the drive motor is connected to a pulley assembly, which is connected to a reduction gearbox. The reduction gearbox drives a vertically arranged lifting screw, and a limit sleeve is provided on the top of the inner wall of the chassis. A lifting rod is threaded onto the external part of the lifting screw, and the top end of the lifting rod extends out of the chassis to support the test platform. The lifting rod is linearly guided by the limit sleeve, and a connecting sleeve is also provided on the lifting rod. One end of the synchronizing rod is fixedly connected to both sides of the connecting sleeve.

[0014] Furthermore, an S-shaped tension / compression sensor is installed below the middle of the upper crossbeam, and the upper pressure head is connected to the lower end of the S-shaped tension / compression sensor; a control panel and a power switch are provided on the front surface of the chassis, and the control panel is electrically connected to the drive motor and the S-shaped tension / compression sensor respectively.

[0015] Further, the process includes the following steps: Step S, Initial State: Under the action of the return spring, the two sets of contact wheels are respectively held on the side close to the sides of the two synchronous rods, at which time the two arc-shaped grippers are in a state away from the test piece; Step S, Upward Centering: Control the test platform to move the test piece upward, the synchronous rod moves upward synchronously and drives the inclined pin block to rise; the first inclined surface at the top first contacts and pushes the contact wheel to move outward, the contact wheel squeezes the return spring through the movable rod and step, so that the arc-shaped grippers move closer to the center of the test platform; when the contact wheel moves to the inclined pin When the block reaches the protruding rounded corner position, the two arc-shaped grippers complete the centering and clamping of the test piece's central disk; Step S, Avoidance Test: As the test platform continues to move upward, the contact wheel gradually transitions past the rounded corner to the second inclined surface below. Under the action of the return spring, the movable through rod retracts, causing the two arc-shaped grippers to move away from the test piece again, completing the avoidance. Subsequently, the upper pressure head contacts the test piece to conduct a strength test; During the entire upward movement, the contact ball always abuts against the surface of the test platform, adapting to the lifting and lowering displacement of the test platform through the telescopic cooperation of the fixed rod and the movable sleeve rod.

[0016] The above-mentioned technical solution adopted by the present invention can achieve the following beneficial effects: A corrugated board ring crush strength testing device, by adding a centering mechanism driven by the upward kinetic energy of the test platform in the testing device, enables the clamping component to automatically and synchronously move towards the center and accurately position the test piece before it contacts the upper pressure head, thereby effectively eliminating the visual errors and operational uncertainties existing in traditional manual visual centering, ensuring that the geometric center of the test piece is highly coincident with the force application center axis of the upper pressure head; thus avoiding the eccentric torque and uneven force generated during the pressing process due to the eccentric placement of the sample, ensuring that the sample ring is damaged under ideal axial pressure, avoiding the situation of falsely low strength values ​​due to eccentric loading, and improving the accuracy, repeatability and reliability of ring crush strength test data and product quality judgment. Attached Figure Description

[0017] The accompanying drawings, which are provided to further illustrate the invention and constitute a part of this invention, are illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention.

[0018] In the accompanying drawings: Figure 1 is an overall schematic diagram of a corrugated board ring crush strength testing device according to this application; Figure 2 is a three-dimensional sectional view of the internal drive structure of the corrugated board ring crush strength testing device of this invention; Figure 3 is a three-dimensional schematic diagram of the installation structure of the centering mechanism in this invention; Figure 4 is an enlarged view of point A in Figure 3; Figure 5 is a three-dimensional schematic diagram of the centering mechanism in its default state in this invention; Figure 6 is a planar structural schematic diagram of Figure 5; Figure 7 is an enlarged view of point B in Figure 6; Figure 8 is a three-dimensional schematic diagram of the centering mechanism after release in this invention; Reference numerals: 1, chassis; 11, control panel; 12, power switch; 13, guide post; 131, opening slot; 14, upper crossbeam 15. Lifting rod; 151. Connecting sleeve; 16. Test platform; 17. S-shaped tension / compression sensor; 18. Upper pressure head; 19. Drive motor; 110. Pulley assembly; 111. Lifting screw; 112. Limiting sleeve; 113. Gearbox; 2. Centering mechanism; 21. Synchronizing rod; 22. Inclined pin block; 221. First inclined plane; 222. Second inclined plane; 23. Fixed bracket; 24. Movable through rod; 25. Connecting end; 26. Step; 27. Return spring; 28. Contact wheel; 29. ​​Fixed rod; 210. Movable sleeve rod; 211. Contact ball; 212. Arc-shaped gripper; 213. Connecting spring. Detailed Implementation

[0019] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0020] The technical solutions provided by various embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Embodiment 1:

[0021] Referring to Figures 1 to 8, the present invention provides a corrugated board ring crush strength testing device, which mainly includes a housing 1, a drive system, a testing component, and a centering mechanism 2 for eliminating manual centering errors.

[0022] As shown in Figures 1 and 2, the chassis 1 serves as the base of the entire device, housing a power source and a supporting structure on top. Specifically, several (usually two) vertically upward guide columns 13 are fixedly installed on the top of the chassis 1. An upper crossbeam 14 is bolted between the top ends of the guide columns 13, thus forming a portal frame structure.

[0023] To achieve the compression action required for the ring crush test, a test platform 16 is installed on top of the chassis 1. This test platform 16 is configured to support the annular sample to be tested (typically including a central disc and a mother disc) and can move vertically up and down. An S-type tension / compression sensor 17 is installed below the middle of the upper crossbeam 14. An upper pressure head 18 is connected to the lower end of the S-type tension / compression sensor 17 and is located directly above the test platform 16. The pressure data during the test can be collected in real time through the S-type tension / compression sensor 17. A control panel 11 and a power switch 12 are provided on the front surface of the chassis 1. The control panel 11 integrates a controller, which is electrically connected to the drive motor 19 and the S-type tension / compression sensor 17, respectively, for controlling the start and stop of the equipment, displaying the test curve, and processing the strength data.

[0024] To achieve smooth lifting and lowering of the test platform 16, referring to Figures 1-2, a drive motor 19 is fixedly mounted on the internal base plate of the chassis 1 via a shock-absorbing seat. The horizontal output shaft of the drive motor 19 is keyed to the driving pulley of the pulley assembly 110. Torque is transmitted to the driven pulley of the pulley assembly 110 via a synchronous toothed belt or V-belt. The driven pulley is coaxially keyed to the input shaft end of the reduction gearbox 113. After speed reduction and torque amplification through the gear set (such as a worm gear or planetary gear set) inside the reduction gearbox 113, the vertically upward output end of the reduction gearbox drives the lifting screw 111.

[0025] The bottom of the lifting screw 111 is rotatably supported on the gearbox 113 by a thrust ball bearing, and the lifting screw 111 only rotates on a fixed axis and does not move axially. A lifting rod 15 is sleeved and threaded on the outside of the lifting screw 111 (or a screw nut that mates with the screw is fixedly embedded inside the lifting rod 15).

[0026] To convert the rotational motion of the lifting screw 111 into the linear motion of the lifting rod 15, as shown in Figures 2-5, a limiting sleeve 112 is fixedly installed at the top (or the opening on the upper surface) of the inner wall of the housing 1. The lifting rod 15 passes through the limiting sleeve 112 and forms a linear guide fit with its inner hole (e.g., through a keyway fit or a non-circular section fit), thereby restricting the degree of freedom of the lifting rod 15 as it rotates with the screw.

[0027] During operation, when the drive motor 19 rotates, it is decelerated by the pulley assembly 110 and the reduction gearbox 113, which drives the lifting screw 111 to rotate in place. Since the lifting rod 15 is restricted by the circumferential limit sleeve 112 and cannot rotate, under the action of the threaded pair, the lifting rod 15 is forced to generate axial displacement in the vertical direction, thereby pushing the test platform 16 above to rise or fall smoothly.

[0028] To address the issue of sample misalignment during manual sample placement in existing technologies, this device incorporates a centering mechanism 2. Referring to Figures 3-8, the design concept of this centering mechanism 2 utilizes the kinetic energy of the rising test platform 16 to mechanically drive the clamping components to synchronously converge towards the center.

[0029] The specific structure is as follows: An axially oriented slot 131 is provided on the side wall of the guide post 13. A connecting sleeve 151 is fixedly fitted onto the lifting rod 15. The centering mechanism 2 includes two sets of symmetrically arranged components, located on both sides of the test piece. Each set of components includes a synchronizing rod 21. One end of the synchronizing rod 21 is fixedly connected to the side of the connecting sleeve 151, and the other end extends upward through the top plate of the housing 1 and through the slot 131 into the interior of the guide post 13. This rigid connection method allows the synchronizing rod 21 to maintain absolutely synchronized lifting and lowering motion with the test platform 16, thereby providing stable linear power for the subsequent drive of the inclined pin block 22.

[0030] A beveled pin block 22 is fixed to the side of the synchronizer rod 21 by screws. The beveled pin block 22 has a triangular plate-like structure with an outwardly protruding rounded corner (i.e., the tip position) on the side opposite to the synchronizer rod 21. The beveled pin block 22 forms two key guide surfaces: a first beveled surface 221 above the rounded corner and a second beveled surface 222 below the rounded corner. The first beveled surface 221 serves as a "feed surface," providing inward thrust during the upward stroke; the second beveled surface 222 serves as a "release surface," allowing the mechanism to reset during subsequent strokes.

[0031] The actuator component mounted on the guide post 13 works in conjunction with the inclined pin block 22. Above the synchronizing rod 21, a fixed bracket 23 is tightly fixed to the outer wall of the guide post 13. A movable through rod 24 is slidably inserted through a horizontally drilled hole in the fixed bracket 23. A rotatable contact wheel 28 is mounted on one end of the movable through rod 24 facing the inclined pin block 22. The position of the contact wheel 28 is designed to allow it to roll and engage with the first inclined surface 221 and the second inclined surface 222 of the inclined pin block 22.

[0032] To achieve automatic reset, a step 26 is provided on the rod portion of the movable through rod 24 located inside the fixed bracket 23, and a reset spring 27 is fitted onto the movable through rod 24. The two ends of the reset spring 27 abut against the inner wall of the fixed bracket 23 and the step 26, respectively. In the initial state or when no external force is applied, the reset spring 27 always applies a pushing force, attempting to push the movable through rod 24 back towards the inclined pin block 22 (i.e., away from the center).

[0033] Considering that the test platform 16 is rising while the fixed support 23 is stationary, in order to ensure that the gripper can always adhere to the surface of the moving test platform 16 and hold the sample, this invention designs a telescopic unit. The telescopic unit includes a connecting end 25 horizontally connected to the other end (i.e., the end near the center) of the movable through rod 24, and a fixed rod 29 is vertically connected downward to the connecting end 25. A movable sleeve rod 210 is sleeved on the outside of the fixed rod 29, and the movable sleeve rod 210 can slide up and down relative to the fixed rod 29 along its axial direction. In order to provide a downward preload to the movable sleeve rod 210, a connecting spring 213 is connected between the end of the fixed rod 29 that extends into the movable sleeve rod 210 and the bottom end of the inner wall of the movable sleeve rod 210.

[0034] The clamping assembly includes two sets of symmetrically arranged arc-shaped grippers 212, which are fixedly mounted on the side walls of the movable sleeves 210 on both sides. The concave surface of the arc-shaped grippers 212 is used to match the outer diameter of the sample center disk, and a flexible pad (such as a rubber pad or silicone pad) is embedded in the contact surface to buffer the rigid impact during contact and prevent damage to the sample.

[0035] In addition, to reduce friction between the centering mechanism 2 and the moving test platform 16, a contact ball 211 (which can be a steel ball or a nylon ball) is embedded in the bottom end of the movable sleeve 210. When the device is working, the contact ball 211 is always in contact with the upper surface of the test platform 16 under the action of the connecting spring 213, and rolls relative to the test platform 16 as it rises. At the same time, the fixed rod 29 and the movable sleeve 210 extend and retract to ensure that the gripper height is adaptive.

[0036] In addition, in order to further improve the smoothness of movement, movable sliding balls (not shown in the figure) can be embedded at the contact positions between the bottom surfaces of the two arc-shaped grippers 212 and the test platform 16. Through multi-point rolling contact, the contact friction between the grippers and the platform surface can be further reduced to prevent scratching the platform surface.

[0037] Working Principle: First Stage: Initial State and Drive Start-up: In the initial state, the test platform 16 is in a low position. Due to the elastic force of the return spring 27, the movable through rod 24 of the centering mechanism 2 is in a retracted state, causing the two sets of arc-shaped grippers 212 to be in an open position away from each other, making it convenient for the operator to place the annular sample to be tested on the test platform 16. When the test starts, the control panel 11 issues a command to start the drive motor 19. After the motor is reduced in speed and torque through the pulley assembly 110 and the reduction gearbox 113, it drives the lifting screw 111 to rotate. Due to the circumferential restriction of the lifting rod 15 by the limit sleeve 112, the rotational motion is converted into the vertical upward linear motion of the lifting rod 15, thereby smoothly pushing the test platform 16 and the synchronous rod 21 to move upward synchronously.

[0038] Phase Two: Mechanical Linkage Automatic Centering: As the test platform 16 rises, the synchronous rod 21, rigidly connected to the lifting rod 15, drives the inclined pin block 22 to move upward synchronously. The first inclined surface 221 (feed surface) of the inclined pin block 22 gradually contacts and presses against the contact wheel 28 on the fixed bracket 23, using the wedge effect to push the contact wheel 28 outward, thereby pushing the movable through rod 24 to overcome the resistance of the return spring 27 and extend towards the center; this action drives the arc-shaped gripper 212 to close inward until the contact wheel 28 reaches the apex of the protruding rounded corner of the inclined pin block 22, at which point the gripper completes the centering of the sample. During this process, the contact ball 211 at the bottom of the arc-shaped gripper 212 always rolls against the surface of the rising test platform 16, and with the extension and retraction between the fixed rod 29 and the movable sleeve rod 210 and the buffering of the connecting spring 213, the gripper can adapt to changes in platform height and follow stably.

[0039] Phase 3: Automatic Avoidance and Crushing Test: As the test platform 16 continues to move upward and approaches the upper pressure head 18, the contact wheel 28 passes the rounded corner apex of the inclined pin block 22 and enters the second inclined plane 222 (release surface). At this time, due to the inward contraction of the inclined plane, under the restoring force of the return spring 27, the contact wheel 28 falls back along the second inclined plane 222, driving the movable through rod 24 to retract, causing the two sets of arc-shaped grippers 212 to automatically open and reset outward, thus completely exiting the test area before the sample is compressed, achieving automatic avoidance. Subsequently, the test platform 16 continues to move upward to allow the centered sample to contact the upper pressure head 18, and the S-shaped tensile and compressive strength sensor 17 collects pressure data in real time until the sample is crushed, completing the ring crush strength test. Example 2:

[0040] A detection method based on the above-mentioned device according to the present invention has the following detailed working process: Step S1, Initial state: Before the test begins, the test platform 16 is in a low position. At this time, the inclined pin block 22 is also in a low position. Under the elastic force of the return spring 27, the two sets of contact wheels 28 respectively adhere to the sides of the two synchronous rods 21 (or the flat surface of the starting end of the inclined pin block 22). At this time, the movable through rod 24 is in a retracted state, driving the two arc-shaped grippers 212 to a position away from the center of the test platform 16, which facilitates the operator to place the sample.

[0041] Step S2, Upward Centering Stage: The operator places the center plate containing the corrugated paper sample on the test platform 16 (precise centering is not required). The equipment is started, and the control panel 11 instructs the drive motor 19 to operate, moving the test platform 16 and the sample upwards. Simultaneously, the synchronous rod 21 connected to the lifting rod 15 moves upwards, causing the inclined pin block 22 to rise. As the inclined pin block 22 rises, its upper first inclined surface 221 begins to contact and press against the contact wheel 28. Due to the wedge effect of the inclined surface, the contact wheel 28 is pushed outwards (i.e., moved away from the guide post 13 and closer to the center of the test platform 16). The contact wheel 28 pushes the movable through rod 24, overcoming the resistance of the return spring 27 and extending inwards. At this time, the movable through rod 24, through the connecting end 25 and the fixed rod 29, drives the arc-shaped gripper 212 towards the center plate of the test piece. When the contact wheel 28 moves to the protruding rounded corner (top) position of the inclined pin block 22, the extension of the movable through rod 24 reaches its maximum value. At this time, the two arc-shaped grippers 212 just close, accurately clamping the center plate of the test piece at the geometric center of the test platform 16, thus achieving automatic centering.

[0042] Step S3, Avoidance and Testing Stage: The test platform 16 continues to rise, bringing the sample closer to the upper pressure head 18. At this time, the inclined pin block 22 continues to rise, and the contact wheel 28 passes the protruding rounded corner and begins to transition to the lower second inclined surface 222. As the second inclined surface 222 contracts inward, the contact wheel 28, under the restoring force of the return spring 27, retracts inward along the second inclined surface 222 (i.e., moves towards the synchronous rod 21). This causes the movable through rod 24 to retract, driving the two arc-shaped grippers 212 to open outward synchronously, moving away from the sample again. When the sample is about to contact the upper pressure head 18, the arc-shaped grippers 212 have completely withdrawn from the test area, achieving automatic avoidance and preventing interference with subsequent pressure tests. Subsequently, the upper pressure head 18 contacts the sample, and the S-shaped tension and compression sensor 17 begins to record pressure data until the sample is crushed, completing the ring crush strength test.

[0043] It is important to note that throughout the entire process, due to the cooperation between the fixed rod 29 and the movable sleeve rod 210, although the test platform 16 is continuously rising, the arc-shaped gripper 212 always "rides" on the test platform 16 via the contact ball 211 at the bottom, automatically adjusting the vertical height difference using the telescopic unit. This design ensures that no matter how high the test platform 16 is raised, the centering mechanism maintains its relative position to the table until centering is completed and it retracts.

[0044] The corrugated board ring crush strength testing device of this embodiment, through a clever pure mechanical linkage structure, transforms the necessary "rising action" of the test into a composite action of "centering + avoidance", eliminating data errors caused by manual centering. Moreover, the structure is stable and does not require an additional drive motor, which greatly improves the accuracy and efficiency of the test.

[0045] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A device for testing the ring crush strength of corrugated sheets, characterized in that: The device includes a chassis (1) with several guide pillars (13) fixedly installed on its top, and an upper crossbeam (14) fixedly connected between the top ends of the guide pillars (13); a test platform (16) located above the chassis (1) and capable of vertical lifting and lowering to carry the test piece; and an upper pressure head (18) located below the upper crossbeam (14) and directly above the test platform (16). The device is characterized in that it further includes a centering mechanism (2), which includes a clamping assembly. The centering mechanism (2) is configured to use the kinetic energy of the test platform (16) when it rises to drive the clamping assembly to move synchronously toward the center, so that the center of the test piece coincides with the force application center of the upper pressure head (18).

2. The corrugated board ring crush strength testing device according to claim 1, characterized in that, The clamping assembly includes two sets of symmetrically arranged arc-shaped grippers (212); the side wall of the guide post (13) is provided with an opening slot (131) along the axial direction; the centering mechanism (2) also includes two sets of symmetrically arranged synchronous rods (21), one end of the synchronous rod (21) extends through the opening slot (131) into the guide post (13) and is connected to the component that drives the test platform (16) to rise and fall, so that the synchronous rod (21) can rise and fall synchronously with the test platform (16); the side of the synchronous rod (21) located outside the guide post (13) is fixedly provided with a slanted pin block (22).

3. The corrugated board ring crush strength testing device according to claim 2, characterized in that, The inclined pin block (22) has a triangular plate structure with a protruding rounded corner on the side opposite to the synchronizing rod (21). The inclined pin block (22) has two inclined surfaces, namely a first inclined surface (221) located above and a second inclined surface (222) located below. The first inclined surface (221) is used to push the arc-shaped gripper (212) inward during the upward movement, and the second inclined surface (222) is used to release the arc-shaped gripper (212) to reset during the continued upward movement.

4. The corrugated board ring crush strength testing device according to claim 3, characterized in that, The centering mechanism (2) further includes a fixed bracket (23), which is tightly fixed on the outer wall of the guide post (13) and located above the synchronizing rod (21); a movable through rod (24) is horizontally slidably passed through the fixed bracket (23), one end of the movable through rod (24) faces the inclined pin block (22) and is equipped with a contact wheel (28), which is adapted to roll and abut against the first inclined surface (221) and the second inclined surface (222).

5. The corrugated board ring crush strength testing device according to claim 4, characterized in that, The movable through rod (24) is provided with a step (26) on the rod body inside the fixed bracket (23), and a return spring (27) is sleeved on the movable through rod (24); the two ends of the return spring (27) abut against the inner wall of the fixed bracket (23) and the step (26) respectively, and are used to always apply a pushing force to the movable through rod (24) in the direction of the inclined pin block (22) in the initial state.

6. The corrugated board ring crush strength testing device according to claim 4, characterized in that, The centering mechanism (2) also includes a telescopic unit for accommodating the relative displacement of the test platform (16) when it rises; the telescopic unit includes a connecting end (25) horizontally connected to the other end of the movable through rod (24), and a fixed rod (29) is vertically connected downward to the connecting end (25); a movable sleeve rod (210) is sleeved on the outside of the fixed rod (29), and the movable sleeve rod (210) can slide up and down along the axial direction of the fixed rod (29); a connecting spring (213) is connected between the end of the fixed rod (29) that extends into the movable sleeve rod (210) and the bottom end of the inner wall of the movable sleeve rod (210).

7. The corrugated board ring crush strength testing device according to claim 6, characterized in that, The arc-shaped gripper (212) is fixedly installed on the side wall of the movable sleeve (210). The arc-shaped gripper (212) has a flexible pad embedded in the inner side of the test piece center plate to buffer the contact pressure. The bottom end of the movable sleeve (210) has a contact ball (211) embedded in it. When the test platform (16) moves the test piece upward, the contact ball (211) abuts against the upper surface of the test platform (16) and generates relative sliding and telescopic displacement as the test platform (16) rises.

8. The corrugated board ring crush strength testing device according to claim 2, characterized in that, The chassis (1) is equipped with a drive motor (19), the output end of which is connected to a pulley assembly (110), and the pulley assembly (110) is connected to a reduction gearbox (113). The reduction gearbox (113) drives a vertically arranged lifting screw (111), and a limit sleeve (112) is provided on the top of the inner wall of the chassis (1). The lifting screw (111) is threaded with a lifting rod (15), and the top of the lifting rod (15) extends out of the chassis (1) to support the test platform (16). The lifting rod (15) and the limit sleeve (112) are linearly guided together, and a connecting sleeve (151) is also provided on the lifting rod (15). One end of the synchronizing rod (21) is fixedly connected to both sides of the connecting sleeve (151).

9. The corrugated board ring crush strength testing device according to claim 8, characterized in that, An S-type tension / compression sensor (17) is installed below the middle of the upper crossbeam (14), and the upper pressure head (18) is connected to the lower end of the S-type tension / compression sensor (17); a control panel (11) and a power switch (12) are provided on the front surface of the chassis (1), and the control panel (11) is electrically connected to the drive motor (19) and the S-type tension / compression sensor (17) respectively.

10. A testing method based on the corrugated board ring crush strength testing device according to any one of claims 3-7, characterized in that, Includes the following steps: Step S1, Initial State: Under the action of the return spring (27), the two sets of contact wheels (28) are respectively kept on the side close to the sides of the two synchronous rods (21), and at this time the two arc-shaped grippers (212) are in a state away from the test piece; Step S2, Upward Centering: Control the test platform (16) to drive the test piece to move upward, the synchronous rod (21) moves upward synchronously and drives the inclined pin block (22) to rise; the first inclined surface (221) located above first contacts and pushes the contact wheel (28) to move outward, the contact wheel (28) squeezes the return spring (27) through the movable through rod (24) and the step (26), so that the arc-shaped grippers (212) move closer to the center of the test platform (16); when the contact wheel (28) moves to the inclined pin block ( When the convex rounded corner of 22) is in position, the two arc-shaped grippers (212) complete the centering and clamping of the test piece center plate; Step S3, avoidance test: As the test platform (16) continues to move upward, the contact wheel (28) passes the rounded corner and gradually transitions to the second inclined surface (222) located below. Under the action of the return spring (27), the movable through rod (24) retracts, driving the two arc-shaped grippers (212) to move away from the test piece again to complete the avoidance. Then the upper pressure head (18) contacts the test piece to perform the strength test; In the entire upward movement process, the contact ball (211) always abuts against the surface of the test platform (16). Through the extension and retraction of the fixed rod (29) and the movable sleeve rod (210), it adapts to the lifting and lowering displacement of the test platform (16).

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