A rebound tonometer

Abstract

This invention relates to a spring-loaded tonometer. The spring-loaded tonometer includes a housing, an internal mounting base, and a probe mounted on one side of the mounting base. The probe includes a mounting shell fixedly connected to the inside of the mounting base. An outer cylinder is located inside the mounting shell, and an inner cylinder is located inside the outer cylinder. A guide is located inside the inner cylinder, and a tail-end limiting member is located inside the mounting shell. The guide includes a probe rod slidably connected inside the inner cylinder. Multiple guide magnetic strips are fixedly mounted on the outer side of the probe rod. A radial permanent magnet is fixedly connected inside the inner cylinder, and a magnetically levitated guide rail is fixedly mounted inside the radial permanent magnet. This invention achieves the beneficial effects of high probe mounting coaxiality, no radial offset in the movement trajectory, and long-term stable measurement accuracy. This structure solves the accuracy drift problem caused by wear of traditional guide rails, improving the repeatability of measurement results and the service life of the equipment.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, specifically to a rebound tonometer. Background Technology

[0002] Glaucoma is the leading cause of irreversible blindness worldwide. Accurate and reliable measurement of intraocular pressure is crucial for early screening, clinical diagnosis, disease progression monitoring, and treatment efficacy evaluation in glaucoma. Rebound tonometers, with their advantages of requiring no ocular surface anesthesia, low operational threshold, fast measurement speed, and excellent patient compliance, have been widely used in ophthalmology clinics, large-scale community glaucoma screenings, and routine care at primary healthcare institutions. They are also suitable for special populations that traditional applanation tonometers cannot cover, such as young children, post-corneal surgery patients, and bedridden patients with limited mobility. Therefore, they are one of the most widely used intraocular pressure measurement devices in the ophthalmology field today.

[0003] In existing rebound tonometers, most use a contact-type physical slide rail as the guide structure for the reciprocating motion of the probe, and a simple snap-fit ​​structure is used to install and fix the disposable probe. During operation, the drive mechanism drives the probe to make axial linear reciprocating motion along the physical slide rail, and the intraocular pressure value is obtained by converting the rebound dynamic parameters after the probe hits the cornea.

[0004] However, the probe snap-on installation in this type of structure is prone to coaxiality deviation, and the long-term reciprocating motion of the contact physical slide rail inevitably leads to mechanical wear. The combined effect of these two factors causes the measurement accuracy of the equipment to drift continuously over time and the measurement results to have poor repeatability, which greatly shortens the effective service life of the equipment and cannot meet the accuracy and stability requirements of long-term, high-frequency use scenarios such as home self-testing and large-scale screening at the grassroots level. Summary of the Invention

[0005] The purpose of this invention is to provide a spring-loaded tonometer, which aims to improve the problems of coaxiality deviation caused by the probe snap-fit ​​installation in the prior art, and the inevitable mechanical wear caused by the long-term reciprocating motion of the contact physical slide rail.

[0006] The objective of this invention is achieved through the following technical solution: a rebound tonometer, comprising a tonometer housing, wherein a mounting base is disposed inside the tonometer housing, and a probe is mounted on one side of the mounting base; The probe includes a mounting shell fixedly connected inside the mounting substrate. An outer cylinder is provided on the inner side of the mounting shell, an inner cylinder is provided on the inner side of the outer cylinder, a guide is provided on the inner side of the inner cylinder, and a tail end limiting member is also provided on the inner side of the mounting shell. The guide component includes a probe rod slidably connected inside the inner cylinder. Multiple guide magnetic strips are fixedly installed on the outer side of the probe rod. A radial permanent magnet is fixedly connected inside the inner cylinder. A magnetic levitation guide rail is fixedly installed inside the radial permanent magnet. The magnetic properties of the magnetic levitation guide rail are the same as those of the guide magnetic strips. A front buffer magnetic ring is fixedly connected to the outer side of the front end of the probe rod. A connecting magnetic ring is installed at the rear end of the probe rod. A rear buffer magnetic ring is magnetically engaged inside the tail end limiting component. The magnetic properties of the connecting magnetic ring are opposite to those of the inner side of the rear buffer magnetic ring.

[0007] As a further description of the above technical solution: The guide also includes two electric conductor rods fixedly connected inside the inner cylinder, with conductive rings fixedly connected to the front ends of the two electric conductor rods and the conductive rings fixedly installed on the outside of the radial permanent magnet; As a further description of the above technical solution: The guide magnetic strip is circumferentially distributed on the outside of the probe rod, and forms a uniform radial magnetic repulsion force with the radial permanent magnet, so that there is a radial suspension gap between the magnetic guide rail and the guide magnetic strip. As a further description of the above technical solution: The outer cylinder includes a rotating cylinder rotatably connected to the inner side of the mounting shell. The rotating cylinder has multiple locking fans inside, and the outer side of the end of the locking fan has an elastic hook. The inner side of the rotating cylinder is fixedly connected to a ramp. As a further description of the above technical solution: The inner cylinder includes a guide cylinder disposed inside the rotating cylinder. A locking groove with a shape adapted to the shape of the locking fan is opened on the outer side of the guide cylinder. A hook groove with a shape adapted to the elastic hook claw is opened at the end of the locking groove, and the opening of the hook groove faces the same direction as the elastic hook claw. A magnetic block is slidably connected inside the front end of the guide cylinder. A scratch-resistant flexible plate is provided on the inner side of the magnetic block. The inner shape of the magnetic block is adapted to the outer shape of the front buffer magnetic ring. A clamping rod is fixedly connected to the outer side of the magnetic block, and the other end of the clamping rod is abutted against the ramp body by magnetic attraction. As a further description of the above technical solution: The tail end limiting component includes a mounting ring fixedly connected to the inner side of the mounting shell. A limiting boss is provided on the inner side of the mounting ring, and the diameter of the limiting boss hole is smaller than the outer diameter of the rear buffer magnetic ring. As a further description of the above technical solution: The inner side of the mounting base plate is provided with a driving component, which includes a main shaft and a secondary shaft rotatably connected to the outer side of the mounting base plate. A switching plate is fixedly connected to the main shaft, and driving magnetic plates are fixedly connected to both ends of the switching plate. The two driving magnetic plates have opposite magnetic properties. A swing main plate and a swing secondary plate are fixedly connected to the outer side of the secondary shaft. A transmission groove is opened at the other end of the switching plate. The top end of the swing main plate is slidably connected to the inside of the transmission groove. The shapes of the two ends of the swing secondary plate are adapted to the shapes of the two sides of the switching plate. As a further description of the above technical solution: The inside of the tonometer housing is equipped with a circuit board. One end of the circuit board is equipped with a motor end. A rotating plate is fixedly connected to the motor end. A connecting post is fixedly connected to the end of the swing main plate. A hinge rod is hinged between the rotating plate and the connecting post. As a further description of the above technical solution: A docking post is provided between the mounting base and the circuit board. A display screen is provided on the outside of the circuit board. A fixed suction head for adsorbing onto the forehead of the person being tested is also provided on the outside of the mounting base.

[0008] Compared with the prior art, the advantages of the present invention are as follows: 1. By rotating the outer cylinder around its central axis, the inner inclined body rotates synchronously, pushing the clamping rod radially inward. This, in turn, causes multiple sets of circumferentially distributed magnetic blocks to synchronously retract inward along the radial groove at the front end of the guide cylinder. This allows the scratch-resistant flexible plate inside the magnetic blocks to adhere to the outer surface of the front buffer magnetic ring, completing the coaxial centering and fixing of the probe. The elastic hook at the end of the locking fan engages in the locking groove, achieving circumferential locking of the rotating cylinder. Furthermore, the guide magnetic strip on the outside of the probe rod and the magnetic levitation guide rail on the radial permanent magnet of the inner cylinder form a repulsive force, causing the probe rod to levitate on the central axis and reciprocate. This eliminates physical contact friction, achieving high probe installation coaxiality, no radial offset in the movement trajectory, and long-term stable measurement accuracy. This structure solves the accuracy drift problem caused by traditional guide rail wear, improving the repeatability of measurement results and the service life of the equipment.

[0009] 2. By forming a magnetic repulsion force between the magnetic block at the front end of the guide cylinder and the front buffer magnetic ring of the probe rod, non-contact buffering is achieved at the extreme position of the probe rod's forward movement. By forming an opposite magnetic attraction force between the magnetic ring at the rear end of the probe rod and the rear buffer magnetic ring inside the mounting ring, deceleration buffering is achieved during the probe rod's rebound process. Combined with the mechanical travel limit of the limiting boss at the front end of the guide cylinder and the inner side of the mounting ring, the maximum reciprocating stroke of the probe rod is limited. This achieves the beneficial effect of smooth buffering and no hard collision impact throughout the entire movement cycle of the probe rod. This structure not only avoids interference of movement impact on measurement data and improves the accuracy of intraocular pressure acquisition, but also eliminates the risk of eye injury caused by probe derailment or excessive forward extension. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the main body of an embodiment of a rebound tonometer proposed in this invention; Figure 2 This is a schematic diagram of the fixed suction head of a spring-loaded tonometer proposed in this invention; Figure 3 This is a schematic diagram of the circuit board structure of a spring-loaded tonometer proposed in this invention; Figure 4 This is a schematic diagram of the probe structure of a rebound tonometer proposed in this invention; Figure 5 This is a schematic diagram of the outer cylinder of a spring-loaded tonometer proposed in this invention; Figure 6 This is a schematic diagram of the guide component of a spring-loaded tonometer proposed in this invention; Figure 7 This is a schematic diagram of the radial permanent magnet structure of a spring-loaded tonometer proposed in this invention; Figure 8 This is a schematic diagram of the inner cylinder of a spring-loaded tonometer proposed in this invention; Figure 9 This is a schematic diagram of the tail end limiting component of a spring-loaded tonometer proposed in this invention; Figure 10 This is a schematic diagram of the structure of the drive component of a spring-loaded tonometer proposed in this invention. Figure 1 ; Figure 11 This is a schematic diagram of the structure of the drive component of a spring-loaded tonometer proposed in this invention. Figure 2 .

[0011] Labeling Explanation: 1. Tonometer housing; 2. Mounting base plate; 3. Docking post; 4. Circuit board; 5. Display screen; 6. Probe; 61. Mounting shell; 62. Outer cylinder; 621. Rotating cylinder; 622. Locking fan; 623. Elastic claw; 624. Inclined body; 63. Inner cylinder; 631. Guide cylinder; 632. Locking groove; 633. Magnetic block; 634. Clamping rod; 64. Guide component; 641. Probe rod; 642. Guide magnetic strip; 643. Radial permanent magnet; 644. Magnetic levitation guide rail; 6 45. Front buffer magnetic ring; 646. Rear buffer magnetic ring; 647. Connecting magnetic ring; 648. Conductive rod; 649. Conductive ring; 65. Tail end limiting component; 651. Mounting ring; 652. Limiting boss; 7. Driving component; 701. Main shaft; 702. Switching plate; 703. Driving magnetic plate; 704. Secondary shaft; 705. Swing main plate; 706. Swing secondary plate; 707. Connecting post; 708. Hinge rod; 709. Rotating plate; 710. Motor end; 711. Transmission groove; 8. Fixed suction head. Detailed Implementation

[0012] The present invention will now be described in detail with reference to the accompanying drawings and embodiments: like Figures 1 to 11 The diagram shows an embodiment of a spring-loaded tonometer provided by the present invention. The spring-loaded tonometer includes a shell 1, which provides sealing protection and positioning for the core internal components of the device. It serves as the basic carrier for holding and operating the device, isolating external dust and moisture from corroding the internal precision structure and ensuring structural stability and safety. Inside the shell 1 is a mounting base 2, which provides coaxial positioning and rigid fixation for core functional components such as the probe 6 and the drive component 7. This serves as a unified mounting reference for the internal structure, ensuring the coaxiality of all moving parts with the measurement reference axis and eliminating the impact of assembly deviations on measurement accuracy. The probe 6 is mounted on one side of the mounting base 2. The probe 6 directly executes the intraocular pressure measurement action and transmits the corneal rebound dynamics. As the core execution component for intraocular pressure measurement, its motion parameters are the core basis for calculating intraocular pressure values. The inner side of the mounting base plate 2 is provided with a drive component 7. The drive component 7 realizes the rapid switching of the device measurement mode and the power transmission of the probe rod 641 axial movement, providing controllable power support for the reciprocating motion of the probe rod 641 and adapting to the parameter requirements of different measurement scenarios.

[0013] A mating post 3 is provided between the mounting base 2 and the circuit board 4. The mating post 3 enables precise docking and rigid fixation of the mounting base 2 and the circuit board 4, ensuring the stability of their electrical connection and isolating mechanical vibration from interference with the circuit board 4, thus ensuring the reliability of the electrical system. A display screen 5 is provided on the outside of the circuit board 4. The display screen 5 provides real-time visualization of intraocular pressure measurement data and device operating status, providing the operator with intuitive measurement results and device status feedback, improving the ease of operation. A fixing suction head 8 is also provided on the outside of the mounting base 2 for adhering to the forehead of the person being tested. The fixing suction head 8 enables rapid adsorption and fixation of the device to the forehead of the person being tested and for positioning the measurement reference, ensuring that the central axis of the device coincides with the normal of the corneal apex during the measurement process, reducing measurement errors caused by hand shake and improving the alignment success rate.

[0014] The probe 6 includes a mounting shell 61 fixedly connected inside the mounting base plate 2. The mounting shell 61 enables coaxial mounting and sealing protection of the outer cylinder 62, inner cylinder 63, guide member 64, and tail end limiting member 65. Serving as the external mounting base for the probe 6 module, it provides a stable mounting space for the precision components inside the probe 6, ensuring the coaxiality of the probe 6 module with the overall reference axis. The outer cylinder 62 is located inside the mounting shell 61. The outer cylinder 62 enables adjustment and locking state switching control for probe centering and fixation, serving as the adjustment component for locking and unlocking the probe and the execution carrier for probe installation and removal. The inner cylinder 63 is located inside the outer cylinder 62. The inner cylinder 63 enables coaxial mounting of the guide member 64, guides and positions the probe insertion, and provides radial constraint for the movement of the magnetic block 633. Serving as the core support for the guide member 64 and probe mounting, it provides a reference cavity for the axial movement of the probe rod 641, ensuring the linearity of the movement trajectory. A guide 64 is provided on the inner side of the inner cylinder 63. The guide 64 enables non-contact levitation guidance and motion parameter sensing and acquisition of the probe rod 641. As a guide and magnetic levitation support component for the movement of the probe rod 641, it eliminates mechanical friction and wear during the movement of the probe rod 641, ensuring the accuracy of motion parameters. A tail end limiting component 65 is also provided on the inner side of the mounting shell 61. The tail end limiting component 65 realizes the installation and fixation of the rear buffer magnetic ring 646, the initial zero point positioning of the probe rod 641, and the limitation of the rear stroke, ensuring that the initial position is consistent for each measurement and eliminating the influence of the initial position error on the measurement results.

[0015] The guide component 64 includes a probe rod 641 slidably connected inside the inner cylinder 63. The probe rod 641 enables the fixed installation of the disposable probe, the execution of axial reciprocating motion, and the transmission of rebound dynamics. As the mounting carrier and magnetized motion component of the disposable probe, its motion state directly reflects the corneal rebound characteristics. Multiple guide magnetic strips 642 are fixedly installed on the outer side of the probe rod 641. The guide magnetic strips 642 achieve uniform radial magnetic repulsion with the magnetic levitation guide rail 644, enabling the probe rod 641 to be radially suspended and positioned. As the core magnetic source component for the magnetic levitation of the probe rod 641, they ensure that the probe rod 641 is always suspended on the central axis, eliminating radial offset and physical contact friction. A radial permanent magnet 643 is fixedly connected inside the inner cylinder 63. The radial permanent magnet 643 enables the fixed installation of the magnetic levitation guide rail 644 and provides a stable magnetic circuit. As the mounting and magnetic circuit bearing component of the magnetic levitation guide rail 644, it provides a stable magnetic field foundation for the magnetic levitation system, ensuring the uniformity and stability of the radial magnetic repulsion. A magnetic levitation guide rail 644 is fixedly installed inside the radial permanent magnet 643. The magnetic levitation guide rail 644 and the guide magnetic strip 642 repel each other with the same pole, forming a radial levitation gap. This allows for contactless guidance of the axial movement of the probe rod 641, eliminating mechanical contact wear at the source and ensuring the absolute linearity of the probe rod 641's movement trajectory, thus improving the long-term stability of measurement accuracy. Furthermore, the magnetic levitation guide rail 644 has the same magnetism as the guide magnetic strip 642, which is circumferentially distributed on the outside of the probe rod 641. It forms a uniform radial magnetic repulsion force with the radial permanent magnet 643, creating a radial levitation gap between the magnetic levitation guide rail 644 and the guide magnetic strip 642. A front buffer magnetic ring 645 is fixedly connected to the outer front end of the probe rod 641. The front buffer magnetic ring 645 forms a magnetic repulsion force with the magnetic block 633, achieving contactless buffering at the front end and coaxial centering during probe installation. This prevents hard collisions at the front end of the probe rod 641 and provides a centering reference for probe installation.

[0016] A connecting magnetic ring 647 is provided at the rear end of the probe rod 641. The connecting magnetic ring 647 forms an opposite magnetic attraction force with the rear buffer magnetic ring 646 to achieve deceleration and buffering at the rear end, and transmit the driving magnetic force. It provides magnetic attraction force for the rebound and reset of the probe rod 641, and at the same time achieves smooth buffering of the rear end movement. The rear buffer magnetic ring 646 is magnetically engaged with the rear end limiting member 65. The rear buffer magnetic ring 646 forms an opposite magnetic attraction force with the connecting magnetic ring 647, and provides deceleration and buffering of the probe rod 641 rebound and initial zero point magnetic positioning. It helps the probe rod 641 stabilize at the initial zero point position and eliminates the impact of rear end collision. Moreover, the magnetism of the connecting magnetic ring 647 is opposite to the inner magnetism of the rear buffer magnetic ring 646. Two conductive rods 648 are fixedly connected inside the inner cylinder 63. The conductive rods 648 realize the transmission of driving current and the acquisition and conduction of induced voltage signals. As the electrical connection of the sensing circuit and the magnetic field driving component, they provide an electrical path for the formation of the driving magnetic field, and at the same time transmit the sensing signal generated by the movement of the probe rod 641. The front ends of the two conductive rods 648 are fixedly connected to conductive rings 649, and the conductive rings 649 are fixedly installed on the outside of the radial permanent magnet 643. The conductive rings 649 realize the generation of axial driving magnetic field by passing pulse current and capture the voltage signal induced by the motion of the probe rod 641. As the core component for generating driving magnetic field and acquiring sensing signal, it provides driving magnetic field for the axial movement of probe rod 641, and at the same time accurately acquires the dynamic parameters of the full cycle movement of probe rod 641.

[0017] The outer cylinder 62 includes a rotating cylinder 621 rotatably connected to the inner side of the mounting shell 61. The rotating cylinder 621 drives the circumferential rotation of the ramp 624 and synchronously transmits the locking fan 622. As the core adjustment and operation component of the outer cylinder 62, it is the direct actuator for locking and unlocking the probe. Multiple locking fans 622 are provided inside the rotating cylinder 621. The locking fans 622 achieve circumferential connection between the rotating cylinder 621 and the guide cylinder 631, providing mechanical locking in the locked state. They work in conjunction with the locking groove 632 to fix the position of the rotating cylinder 621, preventing it from rotating back and loosening in the locked state. The outer end of the locking fan 622 has an elastic hook 623. The elastic hook 623 engages with the hook groove to complete the circumferential anti-loosening locking of the rotating cylinder 621. As an anti-detachment locking component of the locking fan 622, it ensures that the rotating cylinder 621 will not rotate back in the locked state, eliminating the risk of the probe loosening and falling off. An inclined body 624 is fixedly connected to the inner side of the rotating cylinder 621. The inclined body 624 realizes the conversion of circumferential rotational displacement into radial linear displacement of the clamping rod 634. As a transmission component for rotational motion and radial linear motion, it provides continuous thrust for the radial contraction of the magnetic block 633, ensuring the stability of probe centering and clamping.

[0018] The inner cylinder 63 includes a guide cylinder 631 disposed inside the rotating cylinder 621. The guide cylinder 631 is used for machining and forming the locking groove 632, guiding and constraining the radial movement of the magnetic block 633, and coaxially mounting the radial permanent magnet 643. As the core component of the inner cylinder 63, it provides a stable mounting reference for all internal components, ensuring the coaxiality and movement accuracy of each component. A locking groove 632 with a shape adapted to the locking fan 622 is provided on the outer side of the guide cylinder 631. The locking groove 632 guides the sliding of the locking fan 622, limits the rotation angle of the rotating cylinder 621, constrains the movement trajectory of the locking fan 622, and ensures that the rotational action of the rotating cylinder 621 is accurately converted into a locking action. A hook groove with a shape adapted to the elastic hook 623 is provided at the end of the locking groove 632. The hook groove enables the elastic hook 623 to engage and lock, and fixes the locking position of the rotating cylinder 621, providing mechanical engagement and limiting for the locking state and ensuring the stability of the locking state. Furthermore, the opening of the hook groove faces the same direction as the elastic claw 623. A magnetic block 633 is slidably connected inside the front end of the guide cylinder 631. The magnetic block 633 achieves radial clamping and fixing of the front buffer magnetic ring 645, and forms a repulsive force with the front buffer magnetic ring 645 to complete front-end buffering. As the core actuator for probe centering and clamping, it completes the coaxial centering and clamping of the probe, while providing non-contact buffering for the front end of the probe rod 641. A scratch-resistant flexible plate is provided on the inner side of the magnetic block 633. The scratch-resistant flexible plate provides scratch protection for the surface of the front buffer magnetic ring 645, and evenly distributes the clamping stress. As a protective component for contact between the magnetic block 633 and the front buffer magnetic ring 645, it prevents scratches on the surface of the magnetic ring during clamping, while ensuring uniform distribution of clamping force and improving centering accuracy. The inner shape of the magnetic block 633 is adapted to the outer shape of the front buffer magnetic ring 645. A clamping rod 634 is fixedly connected to the outer side of the magnetic block 633. The clamping rod 634 converts the circumferential thrust of the ramp 624 into the radial clamping force of the magnetic block 633. As a transmission intermediate, it accurately transmits the transmission thrust, ensuring that the radial movement of the magnetic block 633 is synchronized with the rotation of the rotating cylinder 621. The other end of the clamping rod 634 is magnetically attracted to the ramp 624.

[0019] The tail-end limiting component 65 includes a mounting ring 651 fixedly connected to the inner side of the mounting shell 61. The mounting ring 651 realizes the installation and fixation of the rear buffer magnetic ring 646 and the machining and forming of the limiting boss 652. As the mounting base of the tail-end limiting component 65, it provides a mounting carrier for the rear-end limiting and buffering structure, ensuring coaxiality with the reference axis of the whole machine. The inner side of the mounting ring 651 is provided with a limiting boss 652. The limiting boss 652 realizes the limitation of the maximum rebound stroke of the probe rod 641 and the mechanical positioning of the initial zero point position. As a mechanical limiting component for the rear stroke of the probe rod 641, it limits the extreme position of the rear end of the probe rod 641, ensuring that the initial zero point of each measurement is completely consistent, while preventing the rear buffer magnetic ring 646 from falling off. Moreover, the diameter of the hole of the limiting boss 652 is smaller than the outer diameter of the rear buffer magnetic ring 646.

[0020] The driving component 7 includes a main rotating shaft 701 and a secondary rotating shaft 704 rotatably connected to the outside of the mounting base plate 2. The main rotating shaft 701 provides fixed-axis rotational support and rotation center positioning for the switching plate 702, ensuring a stable rotational reference for the rotation of the switching plate 702 and guaranteeing the accuracy of the switching position of the driving magnetic plate 703. The secondary rotating shaft 704 provides fixed-axis rotational support and transmission center positioning for the swing main plate 705 and the swing secondary plate 706, providing a stable rotational reference for the swing transmission and guaranteeing the smoothness of the transmission process. The main rotating shaft 701 is fixedly connected to the switching plate 702, which enables the fixed installation of the driving magnetic plate 703 and the rotational switching of the measurement mode. As the mounting and switching carrier for the driving magnetic plate 703, it drives the driving magnetic plates 703 with different magnetic properties at both ends to switch to the working position, completing the switching of the measurement mode. Drive magnetic plates 703 are fixedly connected to both ends of the switching plate 702. The drive magnetic plates 703 provide the axial driving magnetic field and switch the magnetic field parameters for different measurement modes. As the magnetic source component for the axial drive of the probe rod 641, they provide controllable axial magnetic force for the reciprocating motion of the probe rod 641, adapting to the driving requirements of different measurement scenarios. The two drive magnetic plates 703 have opposite magnetic properties. The outer side of the secondary rotating shaft 704 is fixedly connected to the swing main plate 705 and the swing secondary plate 706. The swing main plate 705 realizes the transmission of motor power and drives the rotation of the switching plate 702. As the core linkage component of the drive transmission, it converts the rotational motion of the motor into the fixed-axis rotation of the switching plate 702, completing the position switching of the drive magnetic plates 703.

[0021] The swing sub-plate 706 achieves the limit of the rotation angle of the switching plate 702 and the mechanical stop of the switching position. As a mechanical limit component for the rotation angle of the switching plate 702, it ensures the accurate switching position of the drive magnetic plate 703 and avoids mode switching deviation caused by overtravel rotation. A transmission groove 711 is provided at the other end of the switching plate 702. The transmission groove 711 converts the swing displacement of the swing main plate 705 into the rotational displacement of the switching plate 702. As a transmission connection component between the swing main plate 705 and the switching plate 702, it provides sliding fit space for the transmission between the two, ensuring a smooth and uninterrupted transmission process. The top end of the swing main plate 705 is slidably connected inside the transmission groove 711. The shapes of both ends of the swing sub-plate 706 are adapted to the shapes of the two sides of the switching plate 702. A circuit board 4 is installed inside the tonometer housing 1. The circuit board 4 realizes the output of device drive signals, the acquisition and processing of sensor signals, and the conversion of intraocular pressure data. As the electrical control and data processing center of the whole machine, it completes the logical control and data calculation of the entire measurement process.

[0022] One end of circuit board 4 is equipped with a motor end 710, which outputs driving power and drives the rotation of the rotating plate 709. Serving as the power output component for mode switching, it provides controllable rotational power for precise control of the mode switching angle and speed. The rotating plate 709 is fixedly connected to the motor end 710. The rotating plate 709 converts the motor's rotational motion into the planar reciprocating motion of the hinge rod 708. As a crank transmission component for the motor's power, it acts as a transmission intermediate between the motor and the swing main plate 705, ensuring smooth power transmission. A connecting pin 707 is fixedly connected to the end of the swing main plate 705. The connecting pin 707 enables the hinged connection between the hinge rod 708 and the swing main plate 705, transmitting power and providing a hinge fulcrum for the transmission link, ensuring flexible transmission action. A hinge rod 708 is hinged between the rotating plate 709 and the connecting pile 707. The hinge rod 708 realizes the transmission conversion between the rotational motion of the rotating plate 709 and the swinging motion of the swinging main plate 705. As a transmission link component between the rotating plate 709 and the swinging main plate 705, it accurately transmits power and ensures the synchronization and accuracy of the mode switching action.

[0023] Working principle: The operator attaches the fixed suction head 8 at the front end of the tonometer housing 1 to the forehead of the person being tested. Through negative pressure adsorption, the entire device is fixed in front of the eye being tested, so that the central axis of the device coincides with the normal of the corneal apex of the eye being tested, thus completing the spatial positioning of the device before measurement.

[0024] The operator inserts the compatible disposable probe into the mounting cavity at the front end of the inner cylinder 63, aligning the connecting magnetic ring 647 at the rear end of the probe rod 641 with the rear buffer magnetic ring 646. Then, the probe 6 is pushed inward again, causing the probe rod 641 and the rear buffer magnetic ring 646 to move backward together, so that the front buffer magnetic ring 645 is engaged with the front end of the inner cylinder 63. Then, the rotating cylinder 621 of the outer cylinder 62 is rotated, causing the rotating cylinder 621 to rotate circumferentially around the central axis. The inclined body 624 on the inner side of the rotating cylinder 621 rotates synchronously with the rotating cylinder 621. The inclined surface of the inclined body 624 continuously pushes the clamping rod 634 to move radially inward. The clamping rod 634 drives the magnetic block 633 to retract synchronously inward along the radial groove at the front end of the guide cylinder 631 until the scratch-resistant flexible plate on the inner side of the magnetic block 633 is attached to the outer surface of the front buffer magnetic ring 645, completing the centering and fixing of the probe. As the rotating cylinder 621 rotates, it drives the locking fan 622 to slide along the locking groove 632 on the outside of the guide cylinder 631 until the elastic claw 623 at the end of the locking fan 622 is engaged in the hook groove at the end of the locking groove 632, thus completing the circumferential locking of the rotating cylinder 621 and preventing the rotating cylinder 621 from rotating back on its own and causing the probe to loosen.

[0025] After the probe is locked, the device is powered on. The guide magnetic strips 642 distributed circumferentially on the outer side of the probe rod 641 and the magnetic levitation guide rails 644 on the radial permanent magnets 643 inside the inner cylinder 63 form a magnetic field with opposite poles, generating a radially uniformly distributed magnetic repulsion force. This causes the probe rod 641 to levitate on the central axis of the guide cylinder 631, forming a stable radial levitation gap between the guide magnetic strips 642 and the magnetic levitation guide rails 644. This completely eliminates the physical contact between the probe rod 641 and the guide structure, completing the initial state calibration of the magnetic levitation guide system.

[0026] The operator triggers a mode switching command through the operation buttons on the device. The circuit board 4 outputs a drive signal to the motor end 710. The motor end 710 drives the rotating plate 709 to rotate circumferentially. The rotating plate 709 pulls the connecting pile 707 to move in a plane through the hinge rod 708, which drives the swing main plate 705 to swing around the secondary rotating shaft 704. The top of the swing main plate 705 slides inside the transmission groove 711 of the switching plate 702, thereby driving the switching plate 702 to rotate around the main rotating shaft 701, so that the driving magnetic plates 703 with opposite magnetic properties at both ends of the switching plate 702 are switched to a position coaxial with the central axis of the probe rod 641. Simultaneously, the swing sub-plate 706 rotates synchronously with the sub-rotating shaft 704. The two ends of the swing sub-plate 706 mechanically limit the rotation angle of the switching plate 702 to ensure that the drive magnetic plate 703 is switched into position. In this way, the magnetic force of the drive magnetic plate 703 acts on the rear buffer magnetic ring 646, causing the entire probe rod 641 to reciprocate at a constant speed along the central axis of the magnetic levitation guide rail 644 toward the cornea to be tested. During the movement, the same-pole magnetic repulsion between the guide magnetic strip 642 and the magnetic levitation guide rail 644 always keeps the probe rod 641 in a suspended state, without radial offset or physical friction. Furthermore, during this process, due to the magnetic attraction of the magnetic block 633 and the mounting ring 651, the front buffer magnetic ring 645 and the rear buffer magnetic ring 646 are respectively engaged with the front end of the guide cylinder 631 and the inner side of the mounting ring 651, generating an attraction force, thereby slowing down the circumferential movement speed of the entire probe rod 641, thus achieving a buffering effect and preventing the probe 6 from derailing due to excessive speed and causing damage to the eye under test. In addition, the maximum reciprocating stroke of the probe rod 641 is limited by the limiting protrusion and the shape of the front end of the guide cylinder 631.

[0027] The probe at the front end of the probe rod 641 moves synchronously with the probe rod 641, slightly impacting the corneal apex of the eye to be tested. The elastic deformation of the cornea and the reverse resistance formed by the intraocular pressure cause the probe rod 641 to generate a negative acceleration instantaneously and then rebound along the original axis. The higher the intraocular pressure to be tested, the greater the deceleration of the probe rod 641, the shorter the contact time with the cornea, and the faster the rebound speed. The lower the intraocular pressure to be tested, the smaller the deceleration of the probe rod 641, the longer the contact time with the cornea, and the slower the rebound speed. During the rebound process, the probe rod 641 always stays on the central axis of the magnetic levitation guide rail 644, without radial swaying or trajectory deviation.

[0028] During the rebound of the probe rod 641, the magnetized probe rod 641 reciprocates along the axis, cutting magnetic field lines. This causes the sensing circuit composed of the conductive rod 648 and the conductive ring 649 to generate an induced voltage signal that is linearly positively correlated with the speed and acceleration of the probe rod 641. The circuit board 4 collects this induced voltage signal throughout the entire process, obtaining the dynamic parameters of the probe rod 641 during the entire cycle of emission, impact, deceleration, and rebound, including core data such as initial emission velocity, impact deceleration, rebound velocity, and corneal contact duration. Simultaneously, the circuit board 4 amplifies, filters, and performs analog-to-digital conversion of the signal.

[0029] When the probe rod 641 moves forward to its front limit position, the front buffer magnetic ring 645 on the outer side of the front end of the probe rod 641 and the magnetic block 633 at the front end of the guide cylinder 631 generate a magnetic repulsion force with opposite poles, forming a non-contact front buffer to avoid a hard collision between the probe rod 641 and the front end structure. During the process of the probe rod 641 rebounding to the initial rear end position, the connecting magnetic ring 647 and the rear buffer magnetic ring 646 at the rear end of the probe rod 641 first achieve deceleration and buffering through the opposite magnetic attraction force, and then smoothly fit against the surface of the limiting boss 652 to avoid a hard collision at the rear end. At the same time, the magnetic attraction force helps the probe rod 641 quickly stabilize at the initial zero point position, waiting for the next measurement command.

[0030] The computing unit of circuit board 4 converts the collected dynamic parameters into standard intraocular pressure values ​​using a preset clinical algorithm model, and transmits the conversion results to display screen 5 for real-time display. If multiple measurements are required, the above-mentioned process of drive emission, impact rebound, signal acquisition, and buffer reset is repeated. The device automatically calculates the average and standard deviation of multiple measurement results to complete the entire intraocular pressure measurement process. After all measurements are completed, the operator rotates the rotating cylinder 621 of the outer cylinder 62 in the opposite direction, causing the ramp 624 to rotate and reset synchronously with the rotating cylinder 621. Since the clamping rod 634 is always magnetically attached to the ramp 624, it drives the magnetic block 633 to open radially outward, releasing the probe tail. The elastic hook 623 of the locking fan 622 disengages from the hook groove, releasing the circumferential lock, and the used disposable probe can be pulled out of the device, completing the probe disassembly and replacement.

Claims

1. A spring-loaded tonometer, comprising a tonometer housing (1), characterized in that: The inside of the tonometer housing (1) is provided with a mounting base plate (2), and a probe (6) is mounted on one side of the mounting base plate (2). The probe (6) includes a mounting shell (61) fixedly connected inside the mounting base plate (2). An outer cylinder (62) is provided on the inner side of the mounting shell (61), an inner cylinder (63) is provided on the inner side of the outer cylinder (62), a guide (64) is provided on the inner side of the inner cylinder (63), and a tail end limiting member (65) is also provided on the inner side of the mounting shell (61). The guide (64) includes a probe rod (641) slidably connected inside the inner cylinder (63). Multiple guide magnetic strips (642) are fixedly arranged on the outer side of the probe rod (641). A radial permanent magnet (643) is fixedly connected inside the inner cylinder (63). A magnetic levitation guide rail (644) is fixedly arranged inside the radial permanent magnet (643). The magnetic levitation guide rail (644) has the same magnetism as the guide magnetic strips (642). A front buffer magnetic ring (645) is fixedly connected to the outer side of the front end of the probe rod (641). A connecting magnetic ring (647) is arranged at the rear end of the probe rod (641). A rear buffer magnetic ring (646) is magnetically engaged inside the tail end limiting member (65). The magnetism of the connecting magnetic ring (647) is opposite to the magnetism of the inner side of the rear buffer magnetic ring (646).

2. The rebound tonometer according to claim 1, characterized in that: The guide (64) also includes two electric rods (648) fixedly connected inside the inner cylinder (63). The front ends of the two electric rods (648) are fixedly connected to a conductive ring (649), and the conductive ring (649) is fixedly installed on the outside of the radial permanent magnet (643).

3. The rebound tonometer according to claim 1, characterized in that: The guide magnetic strip (642) is circumferentially distributed on the outside of the probe rod (641), and forms a uniform radial magnetic repulsion force with the radial permanent magnet (643), so that there is a radial suspension gap between the magnetic guide rail (644) and the guide magnetic strip (642).

4. A rebound tonometer according to claim 1, characterized in that: The outer cylinder (62) includes a rotating cylinder (621) rotatably connected to the inner side of the mounting shell (61). The rotating cylinder (621) is provided with multiple locking fans (622). The outer side of the end of the locking fan (622) has an elastic hook (623). The inner side of the rotating cylinder (621) is fixedly connected with a ramp (624).

5. A rebound tonometer according to claim 4, characterized in that: The inner cylinder (63) includes a guide cylinder (631) disposed inside the rotating cylinder (621). The outer side of the guide cylinder (631) is provided with a locking groove (632) whose shape is adapted to the shape of the locking fan (622). The end of the locking groove (632) is provided with a hook groove whose shape is adapted to the elastic hook (623), and the opening of the hook groove faces the same direction as the elastic hook (623). A magnetic block (633) is slidably connected inside the front end of the guide cylinder (631). A scratch-resistant flexible plate is provided on the inner side of the magnetic block (633). The inner shape of the magnetic block (633) is adapted to the outer shape of the front buffer magnetic ring (645). A clamping rod (634) is fixedly connected to the outer side of the magnetic block (633), and the other end of the clamping rod (634) is abutted against the ramp (624) by magnetic attraction.

6. A rebound tonometer according to claim 1, characterized in that: The tail end limiting member (65) includes a mounting ring (651) fixedly connected to the inner side of the mounting shell (61). A limiting boss (652) is provided on the inner side of the mounting ring (651), and the diameter of the limiting boss (652) is smaller than the outer diameter of the rear buffer magnetic ring (646).

7. A rebound tonometer according to claim 1, characterized in that: The inner side of the mounting base plate (2) is provided with a driving component (7). The driving component (7) includes a main rotating shaft (701) and a secondary rotating shaft (704) rotatably connected to the outer side of the mounting base plate (2). The main rotating shaft (701) is fixedly connected to a switching plate (702). The two ends of the switching plate (702) are fixedly connected to driving magnetic plates (703). The two driving magnetic plates (703) have opposite magnetic properties. The outer side of the secondary rotating shaft (704) is fixedly connected to a swing main plate (705) and a swing secondary plate (706). The other end of the switching plate (702) is provided with a transmission groove (711). The top end of the swing main plate (705) is slidably connected to the inside of the transmission groove (711). The shape of the two ends of the swing secondary plate (706) is adapted to the shape of the two sides of the switching plate (702).

8. A rebound tonometer according to claim 7, characterized in that: The inside of the tonometer housing (1) is provided with a circuit board (4), one end of the circuit board (4) is provided with a motor end (710), the motor end (710) is fixedly connected with a rotating plate (709), the end of the swing main plate (705) is fixedly connected with a connecting post (707), and a hinge rod (708) is hinged between the rotating plate (709) and the connecting post (707).

9. A rebound tonometer according to claim 8, characterized in that: A docking post (3) is provided between the mounting base (2) and the circuit board (4). A display screen (5) is provided on the outside of the circuit board (4). A fixed suction head (8) for adsorbing onto the forehead of the person to be tested is also provided on the outside of the mounting base (2).

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