A tablet centering mechanism and hardness detection device

Abstract

This utility model relates to the field of tablet detection technology, and more particularly to a tablet centering mechanism and a hardness detection device, aiming to solve the problem of slow centering speed in existing tablet centering mechanisms. The tablet centering mechanism provided by this utility model includes a first conveying component and a second conveying component; the first conveying component is used to convey material to the second conveying component along a first direction, and includes at least two first conveying rollers, the linear velocity of which decreases progressively along the first direction; the second conveying component is used to convey material to the first conveying component along a second direction, and includes at least one second conveying roller; the second conveying roller rotates in the opposite direction to the adjacent first conveying roller and has the same linear velocity. The tablet posture is adjusted by the friction of the conveying rollers, preventing adhesion and pulling of the tablet due to applied pressure, thus ensuring the adjustment effect. Simultaneously, the first conveying component performs pre-adjustment of the tablet posture, shortening the tablet adjustment time.

Description

Technical Field

[0001] This utility model relates to the field of tablet testing technology, and in particular to a tablet centering mechanism and a hardness testing device. Background Technology

[0002] Before measuring the hardness or size of elongated axisymmetric tablets (such as elliptical, teardrop, or oblong tablets), the tablet testing instrument needs to adjust the tablet's orientation so that the long axis of the tablet is parallel to the direction of movement of the pressure plate, in order to ensure accurate measurement results.

[0003] Existing attitude adjustment devices use cylinders to push pressure plates, which apply pressure to the tablet to straighten it. Because the tablet is very light, typically weighing less than one gram, the tablet may stick to the pressure plates during the clamping and releasing process. This can cause the tablet to be misaligned when the pressure plates detach, thus rendering subsequent measurements ineffective. Utility Model Content

[0004] The purpose of this invention is to provide a tablet alignment mechanism and a hardness detection device to solve the problem of tablet posture deviation caused by the adhesion of tablets in existing tablet posture adjustment devices.

[0005] To solve the above-mentioned technical problems, the technical solution provided by this utility model is as follows:

[0006] This utility model provides a tablet centering mechanism, including a first conveying component and a second conveying component;

[0007] The first conveying assembly is used to convey material to the second conveying assembly along a first direction, and includes at least two first conveying rollers, wherein the linear velocity of the first conveying rollers decreases sequentially along the first direction;

[0008] The second conveying assembly is used to convey material to the first conveying assembly in a second direction, and includes at least one second conveying roller;

[0009] The second conveying roller rotates in the opposite direction to the adjacent first conveying roller, but has the same linear velocity.

[0010] In some alternative embodiments, the diameters of the first conveying rollers are equal, and the rotational speeds of the first conveying rollers decrease sequentially along a first direction.

[0011] In some alternative embodiments, the rotational speeds of each of the first conveying rollers are equal, and the diameters of each of the first conveying rollers decrease sequentially along a first direction.

[0012] In some alternative embodiments, the second conveying roller has the same diameter and rotational speed as the adjacent first conveying roller.

[0013] In some alternative embodiments, the diameter and rotational speed of the second conveyor roller are not equal to those of the adjacent first conveyor roller, and the diameter and rotational speed are inversely proportional.

[0014] In some alternative embodiments, the second conveying assembly includes at least two second conveying rollers, the linear velocity of which decreases sequentially along a second direction.

[0015] In another aspect, this utility model provides a tablet hardness testing device, which includes the tablet centering mechanism described above and a tablet extrusion mechanism.

[0016] The tablet compression mechanism includes a pressure plate and a force sensor, the pressure plate being configured to move toward the force sensor to compress a tablet placed on the tablet centering mechanism.

[0017] Furthermore, the tablet extrusion mechanism also includes a lead screw, the axis of which is parallel to the axis of the first conveying roller, and the lead screw rotates about its own axis to drive the pressure plate to move toward the force sensor.

[0018] Furthermore, the tablet compression mechanism also includes a motor, which drives the lead screw to rotate around its own axis.

[0019] Furthermore, the motor is configured as a servo motor with an absolute encoder.

[0020] Based on the above technical solutions, the technical effects achieved by this utility model are as follows:

[0021] The tablet alignment mechanism provided by this utility model includes a first conveying component and a second conveying component; the first conveying component is used to convey material to the second conveying component along a first direction, and includes at least two first conveying rollers, the linear velocity of the first conveying rollers decreasing sequentially along the first direction; the second conveying component is used to convey material to the first conveying component along a second direction, and includes at least one second conveying roller; the second conveying roller rotates in the opposite direction to the adjacent first conveying roller and has the same linear velocity.

[0022] The tablet centering mechanism provided by this utility model serves to both support the tablet and adjust its posture. When the tablet enters through the first conveying assembly, if the length direction of the tablet is not parallel to the axis of the first conveying roller, then as the tablet moves along the first direction, both ends of the tablet will contact the two adjacent first conveying rollers respectively. Due to the difference in linear velocity between the two adjacent first conveying rollers, the first conveying roller with the smaller linear velocity will hinder the tablet's forward movement through friction, thereby causing the tablet to oscillate in the horizontal plane parallel to the axis of the first conveying roller, reducing the angle between the length direction of the tablet and the axis of the first conveying roller.

[0023] When the tablet arrives at the adjacent first and second conveyor rollers, since they rotate in opposite directions and have the same linear velocity, the tablet eventually completes its posture adjustment under the drive of the first and second conveyor rollers, so that the length direction of the tablet is parallel to the axis of the first conveyor roller and symmetrical about the middle plane of the adjacent first and second conveyor rollers. At the same time, it is supported by the adjacent first and second conveyor rollers for subsequent processes.

[0024] The tablet alignment mechanism provided by this invention adjusts the tablet posture through the friction of the conveying rollers, preventing the tablets from sticking or being pulled due to applied pressure, thus ensuring the adjustment effect. Simultaneously, the first conveying assembly pre-adjusts the tablet posture, minimizing the angle between the tablet's length direction and the axis of the first conveying roller, thereby shortening the adjustment time of the tablet on the adjacent first and second conveying rollers and improving adjustment efficiency. Attached Figure Description

[0025] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0026] Figure 1 A schematic diagram of the tablet alignment mechanism provided in this embodiment of the utility model;

[0027] Figure 2 This is a cross-sectional schematic diagram of the tablet hardness testing device provided in an embodiment of the present invention;

[0028] Figure 3 This is a schematic diagram of the tablet compression mechanism.

[0029] Icons: 10, tablet centering mechanism; 20, tablet compression mechanism; 110, first conveying assembly; 120, second conveying assembly; 130, centering bracket; 111, first conveying roller; 121, second conveying roller; 210, pressure plate; 220, force sensor; 230, lead screw; 240, motor; 250, connecting rod; 260, slider; 270, connecting frame; 280, sensor mounting plate. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0031] The following detailed description, in conjunction with the accompanying drawings, outlines some embodiments of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0032] The existing attitude adjustment device uses a cylinder to push the pressure plate 210, so that the two pressure plates 210 apply a certain pressure to the tablet, thereby straightening the tablet. Since the tablet is very light, usually weighing less than one gram, the tablet may stick to the pressure plate 210 when it clamps and releases. This can cause the tablet to be misaligned when the pressure plate 210 detaches from the tablet, thus making subsequent measurement actions fail.

[0033] In view of this, the present invention provides a tablet centering mechanism, including a first conveying assembly 110 and a second conveying assembly 120; the first conveying assembly 110 is used to convey material to the second conveying assembly 120 along a first direction, and includes at least two first conveying rollers 111, wherein the linear velocity of the first conveying rollers 111 decreases sequentially along the first direction; the second conveying assembly 120 is used to convey material to the first conveying assembly 110 along a second direction, and includes at least one second conveying roller 121; the second conveying roller 121 rotates in the opposite direction to the adjacent first conveying roller 111 and has the same linear velocity.

[0034] The tablet centering mechanism provided by this utility model serves to both support the tablet and adjust its posture. When the tablet enters through the first conveying assembly 110, if the length direction of the tablet is not parallel to the axis of the first conveying roller 111, then as the tablet moves along the first direction, both ends of the tablet will contact the two adjacent first conveying rollers 111 respectively. Due to the difference in linear velocity between the two adjacent first conveying rollers 111, the first conveying roller 111 with the smaller linear velocity will hinder the tablet's forward movement through friction, thereby causing the tablet to oscillate in the horizontal plane parallel to the axis of the first conveying roller 111, reducing the angle between the length direction of the tablet and the axis of the first conveying roller 111.

[0035] When the tablet arrives at the adjacent first conveyor roller 111 and second conveyor roller 121, since the two rotate in opposite directions and have the same linear velocity, the tablet finally completes its posture adjustment under the drive of the first conveyor roller 111 and second conveyor roller 121, so that the length direction of the tablet is parallel to the axis of the first conveyor roller 111 and symmetrical about the middle plane of the adjacent first conveyor roller 111 and second conveyor roller 121. At the same time, it is supported by the adjacent first conveyor roller 111 and second conveyor roller 121 for subsequent processes.

[0036] The tablet alignment mechanism provided by this invention adjusts the tablet posture through the friction of the conveying rollers, preventing the tablets from sticking or being pulled due to applied pressure, thus ensuring the adjustment effect. Simultaneously, the first conveying assembly 110 pre-adjusts the tablet posture, minimizing the angle between the tablet's length direction and the axis of the first conveying roller 111, thereby shortening the adjustment time of the tablet on the adjacent first and second conveying rollers 111 and improving adjustment efficiency.

[0037] The following combination Figures 1-3 The structure and shape of the tablet centering mechanism and hardness testing device provided in this embodiment are described in detail.

[0038] In an optional embodiment, the diameters of all the first conveying rollers 111 are equal, and the rotational speed of each of the first conveying rollers 111 decreases sequentially along the first direction, thereby ensuring that the linear velocity of each of the first conveying rollers 111 decreases sequentially along the first direction. At this time, the heights of all the first conveying rollers 111 are equal to ensure that a horizontal surface is formed for the tablets to pass through.

[0039] In an optional embodiment, the rotational speeds of each of the first conveying rollers 111 are equal, the diameters of each of the first conveying rollers 111 decrease sequentially along the first direction, and the linear velocity of each of the first conveying rollers 111 decreases sequentially along the first direction. At this time, the apex heights of each of the first conveying rollers 111 are the same to ensure that a horizontal surface is formed for the tablets to pass through.

[0040] In an optional embodiment, the second conveying roller 121 has the same diameter and rotation speed as the adjacent first conveying roller 111, so as to finally complete the posture adjustment of the tablet and make the length direction of the tablet parallel to the axial direction of the first conveying roller 111.

[0041] In an optional embodiment, the diameter and rotational speed of the second conveying roller 121 are not equal to those of the adjacent first conveying roller 111, and the diameter and rotational speed are inversely proportional, thereby ensuring that the linear speed of the second conveying roller 121 is equal to that of the adjacent first conveying roller 111.

[0042] In an optional embodiment, the second conveying assembly 120 includes at least two second conveying rollers 121. Along the second direction, the linear velocity of the second conveying rollers 121 decreases one by one, at which time the tablet can enter the tablet centering mechanism from the second conveying assembly 120.

[0043] In practical applications, the linear velocity can be varied by changing the diameter of the conveyor roller. Compared to using precision gears with different numbers of teeth to change the rotational speed, maintaining the same rotational speed and adjusting the linear velocity by changing the diameter of the conveyor roller is less costly to manufacture, enabling mass production of gears and reducing the variety of gear types.

[0044] Specifically, such as Figure 1 As shown, in this embodiment, the tablet centering mechanism is equipped with ten conveying rollers of equal diameter. These ten rollers are divided into two groups, forming the first conveying assembly 110 and the second conveying assembly 120, respectively. The first conveying rollers 111 are numbered 1-5 along the first conveying direction, and the second conveying rollers 121 are numbered 1-5 along the second conveying direction. The adjacent first conveying roller 5 (111) and second conveying roller 5 (221) constitute the hardness testing station, where the two rollers jointly support the tablet for hardness testing. During the process of the tablet entering the hardness testing station from the first conveying assembly 110, if the length direction of the tablet is not parallel to the axis of the first conveying roller 111, both ends of the tablet will contact the two first conveying rollers 111 respectively. For example, when the two ends of the tablet are located at first conveying roller 111 and first conveying roller 2 (211), the slower speed of the higher-numbered first conveying roller 2 will obstruct the tablet, causing it to swing in the horizontal plane. That is, by using the speed difference, the length direction of the tablet is swung in a direction parallel to the axis of the first conveying roller 111, thereby minimizing the angle between the length direction of the tablet and the axis of the first conveying roller 111. When the tablet comes into contact with the adjacent No. 5 first conveying roller 111 and No. 5 second conveying roller 121, the tablet finally completes the posture adjustment under the obstruction of the No. 5 second conveying roller 121.

[0045] By setting multiple first conveying rollers 111 and second conveying rollers 121 and gradually decreasing rotation speeds along the conveying direction, the tablets begin to adjust their posture as soon as they enter the first conveying component 110 or the second conveying component 120 of the tablet centering mechanism, thereby reducing the time it takes for the tablets to adjust their posture when they reach the hardness detection station, i.e., when they reach adjacent first conveying rollers 111 and second conveying rollers 121.

[0046] In this embodiment, the tablet centering mechanism further includes a centering bracket 130, on which the first conveying roller 111 and the second conveying roller 121 are both mounted. The speed difference can be achieved by changing the transmission ratio through gear transmission, synchronous belt transmission, etc. The first conveying component 110 and the second conveying component 120 can be driven by the same power source or driven separately. The power source can be a servo motor, a stepper motor, or a constant speed motor, etc.

[0047] The tablet centering mechanism provided in this embodiment has a simple and reliable structure, with only the rotation of the conveying roller. Compared with tablet posture adjustment devices driven by pneumatic components, it has the advantages of low equipment cost, high precision and working stability, low failure rate, and convenient maintenance.

[0048] Through detailed testing and simulation of the conveyor roller dimensions and gaps, the tablet centering mechanism is designed to be suitable for centering all round and elongated axisymmetric tablets ranging in size from 5mm to 25mm. This essentially covers the vast majority of common tablet shapes and sizes on the market. No manual adjustment is required during use, improving the equipment's versatility and reducing the workload for users. Specifically, the conveyor roller diameter is 3mm, the gap between the conveyor rollers is 1.5mm, and the speed ratio between adjacent conveyor rollers is 1.15~1.2.

[0049] Based on the tablet alignment mechanism provided in this embodiment, a tablet hardness detection device is proposed, which includes the tablet alignment mechanism 10 described above, and also includes a tablet compression mechanism 20.

[0050] Specifically, the tablet compression mechanism 20 includes a pressure plate 210 and a force sensor 220. The pressure plate 210 and the force sensor 220 are disposed on both sides of the tablet. The pressure plate 210 is configured to move toward the force sensor 220 to compress the tablet placed on the tablet centering mechanism 10.

[0051] In this embodiment, the tablet compression mechanism 20 also includes a lead screw 230, the axis of which is parallel to the axis of the first conveying roller 111. The lead screw 230 rotates around its own axis to drive the pressure plate 210 to move toward the force sensor 220.

[0052] In this embodiment, the tablet compression mechanism 20 also includes a motor 240, which drives the lead screw 230 to rotate around its own axis.

[0053] In this embodiment, motor 240 is configured as a servo motor with an absolute encoder to ensure precise position control. The servo motor is connected to lead screw 230 via a coupling; the absolute encoder provides absolute position information of the motor 240 shaft. When working in conjunction with the servo motor, the movement of the servo motor can be accurately controlled based on the precise position data fed back by the absolute encoder, enabling it to precisely reach the target position. Furthermore, the torque limiting of the servo motor prevents excessive compression of the tablet.

[0054] In this embodiment, the tablet compression mechanism 20 further includes a connecting rod 250, a slider 260, and a connecting frame 270. A motor 240 is mounted on the connecting frame 270, a lead screw 230 is rotatably mounted on the connecting frame 270, and a slider 260 is slidably mounted on the connecting frame 270. The slider 260 is fitted onto the lead screw 230 and threadedly connected to it. One end of the connecting rod 250 is connected to the pressure plate 210, and the other end is connected to the slider 260. To ensure the stability of the pressure plate 210, at least two connecting rods 250 are provided. During operation, the motor 240 drives the lead screw 230 to rotate, causing the lead screw 230 to slide the slider 260, which in turn moves the pressure plate 210 to compress the tablet.

[0055] In this embodiment, the motor 240, lead screw 230, coupling, slider 260, and connecting frame 270 can be integrated into a linear module to improve integration and reduce costs. A high-precision lead screw 230 is used to ensure operational accuracy; specifically, the lead screw 230's accuracy can be set to a stroke variation of less than 0.012mm within any 300mm stroke.

[0056] The tablet compression mechanism 20 also includes a sensor mounting plate 280, a force sensor 220 mounted on the sensor mounting plate 280, and the sensor mounting plate 280 mounted on the centering bracket 130.

[0057] It should be noted that the conveying roller of the centering mechanism 10 rotates continuously until the measurement is completed, to avoid the tablet from shifting during the measurement process, thereby ensuring the accuracy of the measurement results.

[0058] When a tablet is broken, if the size of the broken particles is smaller than the minimum gap between adjacent conveyor rollers, they can fall through the gap. If the particle size is larger than the minimum gap but smaller than the maximum gap, the particles will be squeezed by the two adjacent conveyor rollers due to their opposite rotation directions or speed difference, and further broken into particles smaller than the minimum gap. These particles will then fall through the gap and be discharged, preventing residual particles from affecting subsequent tablet detection. If the particle size is larger than the maximum gap, the rotation direction of the conveyor rollers can be reversed to discharge the particles. This process prevents the accumulation of broken tablet powder from affecting the accuracy of subsequent measurements. It should be noted that the maximum gap between adjacent conveyor rollers is the distance between the apexes of the adjacent conveyor rollers.

[0059] The working process of the tablet compression mechanism 20 provided in this embodiment includes three stages: approaching the tablet, contacting the tablet, and compressing the tablet. The specific implementation process is as follows:

[0060] During the tablet approach phase: The control system calculates the displacement required for the pressure plate 210 to rapidly approach the tablet from its initial position based on the standard tablet size (diameter or length) input by the user. This displacement is then converted into the number of rotations required for the motor 240 to drive the lead screw 230. The servo motor with an absolute encoder then drives the lead screw 230 to rotate the corresponding number of rotations at its maximum permissible speed. This causes the pressure plate 210 to rapidly approach the tablet at a relatively high speed to a position slightly larger than the tablet's diameter or length, minimizing the time required for the pressure plate 210 to approach the tablet.

[0061] During the tablet contact stage, the control system automatically adjusts the servo motor speed, using a high-precision lead screw 230 to adjust the movement speed of the pressure plate 210 to 1~5mm / s. The movement speed varies slightly depending on the standard size of the tablet; larger tablets require a higher movement speed. The pressure plate 210 moves at a uniform speed to approach and contact the tablet until the force sensor 220 detects a pressure not exceeding 10N or the servo motor detects an increase in torque, whichever comes first. This ensures reliable contact between the pressure plate 210 and the tablet without crushing it, guaranteeing stable tablet posture during compression to achieve accurate hardness.

[0062] During the tablet compression stage, the control system captures the changes in force and torque of the servo motor in real time by the force sensor 220. Based on the acquired force and torque data, it makes real-time adjustments to achieve a linear increase in force over time during the compression process, ensuring that the force change is as close as possible to a straight line from the time the tablet is subjected to pressure to when it breaks.

[0063] At the moment the tablet breaks, there will be a sudden drop in pressure from the force sensor 220 and torque from the servo motor, whichever comes first. Since the entire force measurement curve is approximately linear, the sudden drop in torque from the force sensor 220 and the motor 240 will be clear and significant, allowing for a clear and accurate capture of the peak pressure before the tablet breaks, i.e., the tablet's hardness.

[0064] This measurement process can quickly detect the sudden drop in force the moment the tablet breaks, promptly stopping the pressure of the pressure plate 210 on the tablet and preventing secondary crushing of the already broken tablet, which would cause inconsistencies in peak pressure. This improves the accuracy of tablet hardness measurement. When the force sensor 220 fails to capture the pressure at the moment of tablet breakage due to the sampling time interval, and instead determines the tablet breakage time by the decrease in the torque of the motor 240, the pressure exerted on the tablet during breakage, i.e., the tablet hardness, can be determined based on the linear relationship between pressure and time.

[0065] In contrast, conventional measurement methods that use a pressure plate 210 moving at a constant speed for compression result in a relatively flat and non-linear stress change curve measured by the force sensor 220 before the tablet breaks. This makes it impossible to estimate the maximum pressure before breakage based on the time of the torque drop, and the force drop is easily overlooked, leading to secondary tablet breakage. Furthermore, due to the sampling time interval of the force sensor 220, the captured maximum pressure is difficult to match the actual pressure peak, resulting in a significant deviation between the measurement results and the actual pressure.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A tablet centering mechanism, characterized in that, It includes a first conveying assembly (110) and a second conveying assembly (120); The first conveying assembly (110) is used to convey material to the second conveying assembly (120) along a first direction, and includes at least two first conveying rollers (111), wherein the linear velocity of the first conveying rollers (111) decreases sequentially along the first direction; The second conveying assembly (120) is used to convey material to the first conveying assembly (110) in a second direction, and includes at least one second conveying roller (121). The second conveying roller (121) rotates in the opposite direction to the adjacent first conveying roller (111) and has the same linear velocity.

2. The tablet alignment mechanism according to claim 1, characterized in that, The diameters of each of the first conveying rollers (111) are equal, and the rotational speed of each of the first conveying rollers (111) decreases sequentially along the first direction.

3. The tablet alignment mechanism according to claim 1, characterized in that, The rotational speeds of each of the first conveying rollers (111) are equal, and the diameters of each of the first conveying rollers (111) decrease sequentially along the first direction.

4. The tablet alignment mechanism according to claim 1, characterized in that, The second conveying roller (121) has the same diameter and the same rotation speed as the adjacent first conveying roller (111).

5. The tablet alignment mechanism according to claim 1, characterized in that, The diameter and rotational speed of the second conveying roller (121) are not equal to those of the adjacent first conveying roller (111), and the diameter and rotational speed are inversely proportional.

6. The tablet alignment mechanism according to claim 1, characterized in that, The second conveying assembly (120) includes at least two second conveying rollers (121), and the magnitude of the linear velocity of the second conveying rollers (121) decreases sequentially along the second direction.

7. A tablet hardness testing device, characterized in that, It includes a tablet centering mechanism (10) as described in any one of claims 1-6, and also includes a tablet compression mechanism (20). The tablet compression mechanism (20) includes a pressure plate (210) and a force sensor (220), the pressure plate (210) being configured to move toward the force sensor (220) to compress a tablet placed on the tablet centering mechanism (10).

8. The tablet hardness testing device according to claim 7, characterized in that, The tablet compression mechanism (20) also includes a lead screw (230), the axis of which is parallel to the axis of the first conveying roller (111), and the lead screw (230) rotates about its own axis to drive the pressure plate (210) to move toward the force sensor (220).

9. The tablet hardness testing device according to claim 8, characterized in that, The tablet compression mechanism (20) also includes a motor (240) for driving the lead screw (230) to rotate around its own axis.

10. The tablet hardness testing device according to claim 9, characterized in that, The motor (240) is configured as a servo motor with an absolute encoder.

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