Automatic stop type miniature rat cranial drill based on AMR magnetic resistance current sensor

Abstract

The utility model provides an AMR magnetoresistive current sensor-based self-stop miniature rat skull drill, which comprises a bracket, an electric push rod lifting mechanism, an electric skull drill and a control box, and is characterized in that the bracket is used for bearing an experimental animal and supporting the electric push rod lifting mechanism; the electric skull drill is installed at the bottom end of the electric push rod lifting mechanism, a drill bit faces the experimental animal, and the power connection end of a driving motor of the electric skull drill is connected with an AMR magnetic resistance current sensor. The electric push rod lifting mechanism is used for driving the electric skull drill to lift; a single-chip microcomputer is arranged in the control box and used for receiving current detected by the current sensor and controlling starting and stopping of the electric push rod lifting mechanism and the electric skull drill. By the adoption of the technical scheme, operation of the skull drill can be simpler and more accurate, and the accuracy and reliability of rat brain experiment research can be improved.

Description

Technical Field

[0001] The utility model relates to the technical field of medical experimental instruments and equipment, and in particular to a self-stopping mini rat skull drill based on an AMR magnetoresistive current sensor. Background Art

[0002] With the progress of society and the development of scientific research, the requirements for high-precision technology levels are also increasing, and the diversification and convenience of experimental methods have gradually become a trend. The development of a portable self-stop skull drill is a scientific research project approved by the Drug Instrument Inspection Institute of the General Logistics Department and the Ministry of Health in 1994. It is used in neurosurgery to perform skull drilling and craniotomy on cranial patients or experimental animals. At present, most skull drills on the market are similar. Common skull drills include high-speed drills and manual drills. High-speed drills are suitable for fast skull drilling, but have low precision and a small range of application; manual drills are suitable for more delicate operations, but are overly dependent on manual labor. Traditional electric skull drills cannot achieve self-stopping of the drill bit, and the operator needs to have rich experience to accurately control the stop of the drill bit.

[0003] In experiments that require delicate operations, such as studying the pathological mechanisms of the brain of experimental animals, the requirements for operating skull drills are becoming increasingly higher, and it is far from enough to rely solely on manual operation of handheld skull drills. The applicant found a series of serious defects in the use and experimental verification of the handheld bone drill. First, due to human factors during the use of the handheld bone drill, the skull drill may not stop rotating in time, the manual operation is usually cumbersome and slow, and the high temperature generated by the high-speed rotation will cause local thermal damage to the experimental animals. Although the drill bit can be stopped manually for cooling, this will extend the experimental time and increase the amount of manual operation. Second, the handheld bone drill requires manual operation. After a long period of operation, the operator will inevitably experience fatigue and hand shaking, which often causes additional damage to the brain tissue of the experimental animal, causing errors in the research results and data analysis. Third, the shaking of the handheld bone drill itself will also affect the positioning accuracy and drilling quality. These problems not only consume human resources, but also pose the risk of technical operation errors.

[0004] Therefore, in order to enable researchers to reduce damage to the brain tissue of experimental animals while exploring brain structure and function, make skull drill operations more precise and safe, and reduce dependence on human resources, it is necessary to improve the skull drill. Utility Model Content

[0005] In order to better solve the above problems, the utility model provides a self-stop mini rat skull drill based on an AMR magnetoresistive current sensor, which simplifies the skull drill operation and helps to improve the accuracy and reliability of experimental research on the rat brain.

[0006] To achieve the above-mentioned purpose, an embodiment of the utility model provides a self-stopping mini rat skull drill based on an AMR magnetoresistive current sensor, comprising: a bracket, comprising a base, a bearing plate, a support column, and a fixing frame, wherein the bearing plate is fixed above the base, the support column is arranged on the bearing plate, and the first end of the fixing frame is connected to the support column; an electric push rod lifting mechanism, comprising a housing and a DC motor, a gear reduction assembly, and a screw rod arranged in the housing, wherein the DC motor is connected to the screw rod through the gear reduction assembly, and the DC motor can drive the screw rod to rise and fall when it rotates; the housing is installed at the second end of the fixing frame and is located above the bearing plate; an electric skull drill, which is installed at the bottom end of the screw rod with the drill bit facing the bearing plate, and the power connection end of the drive motor of the electric skull drill is connected to the AMR magnetoresistive current sensor; a control box, wherein a single-chip microcomputer is arranged in the control box, and the single-chip microcomputer is electrically connected to the AMR magnetoresistive current sensor, the DC motor, and the drive motor respectively, and receives the current of the drive motor detected by the AMR magnetoresistive current sensor, and controls the start and stop of the DC motor and the electric skull drill.

[0007] Optionally, the electric push rod lifting mechanism also includes a travel switch assembly, including upper and lower travel switches and a stopper, the upper and lower travel switches are respectively arranged in the upper part and the middle and lower part of the shell, and the stopper is arranged on the screw rod and located between the upper and lower travel switches.

[0008] Optionally, the control box is provided with a plurality of operation buttons, including a start button, a stop button, a forward button, and a reverse button, and the single chip microcomputer is electrically connected to the plurality of operation buttons respectively.

[0009] Optionally, the control box is provided with a plurality of indicator lights, including a start indicator light, a stop indicator light, a forward indicator light, and a reverse indicator light.

[0010] Optionally, the fixing frame comprises a retractable upper push-pull rod and a lower push-pull rod, and a first limiting structure is provided on the upper push-pull rod and the lower push-pull rod for locking the upper push-pull rod and the lower push-pull rod.

[0011] Optionally, the support column is rotatably disposed on the bearing plate, and a second limiting structure is provided at a rotation connection of the support column for locking the support column.

[0012] Optionally, a calibration component is also included, which is a horizontal gyroscope, arranged on the top of the electric push rod lifting mechanism.

[0013] The self-stopping miniature rat skull drill based on the AMR magnetoresistive current sensor of the embodiment of the utility model is provided with a bracket to carry the experimental animal, support the electric push rod lifting mechanism and the electric skull drill, so that the drill bit is located above the experimental animal, and the electric push rod lifting mechanism can be used to drive the drill bit up and down; and by providing a magnetoresistive current sensor to detect the current of the driving motor of the electric skull drill, it can be used to judge the bone drilling process of the drill bit and control the electric skull drill to stop and rise in time when the skull is drilled. The self-stopping miniature rat skull drill realizes full automatic control, greatly improves the drilling efficiency, makes the operation of the skull drill more precise and safe, reduces the damage to the experimental animals, and reduces the dependence on human resources.

[0014] The self-stop micro rat skull drill also designs the support column to be rotatable and the fixing frame to be retractable, which makes it convenient for the operator to adjust the position of the skull drill; and multiple operation buttons are set to facilitate the operator to select automatic mode and manual mode during the experiment. In the manual automatic mode, the experiment process can be completed only by operating the motor button. The operation is simple, which can reduce the errors caused by manual operation technology and make the research results and data analysis more accurate.

[0015] The self-stop micro rat cranial drill has the advantages of simple structure, convenient operation, reliable performance, and low cost, and can effectively improve the quality and reliability of rat brain experiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0017] Figure 1 This is a schematic diagram of the structure of a self-stop mini rat cranial drill according to an embodiment of the utility model;

[0018] Figure 2 A schematic diagram of a portion of the structure of a self-stopping mini rat cranial drill according to an embodiment of the utility model;

[0019] Figure 3 It is a structural schematic diagram of the electric push rod lifting structure and the electric skull drill according to an embodiment of the utility model;

[0020] Figure 4 A control logic schematic diagram of an embodiment of the utility model;

[0021] Figure 5 A schematic diagram of the skull drilling process of an embodiment of the utility model;

[0022] Figure 6 A schematic diagram of the change of the current signal during the drilling process of the skull drill according to an embodiment of the utility model;

[0023] Figure 7 This is a control logic diagram of a control box according to an embodiment of the utility model.

[0024] Reference numerals:

[0025] 1. Bracket; 11. Base; 12. Loading plate; 13. Support column; 14. Fixed frame; 15. Horizontal gyroscope; 2. Electric push rod lifting mechanism; 3. Electric skull drill; 4. Control box. DETAILED DESCRIPTION

[0026] In order to make the above-mentioned purposes, features and advantages of the utility model more obvious and easy to understand, the specific implementation methods of the utility model are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the utility model. However, the utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the utility model. Therefore, the utility model is not limited to the basic implementation disclosed below.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0028] like Figure 1-3 As shown, the self-stopping mini rat skull drill based on the AMR magnetoresistive current sensor of the embodiment of the utility model comprises a bracket 1, an electric push rod lifting mechanism 2, an electric skull drill 3 and a control box 4, wherein the bracket 1 comprises a base 11, a bearing plate 12, a support column 13, and a fixing frame 14, the bearing plate 12 is fixed above the base 11, the support column 13 is arranged on the bearing plate 12, and the first end of the fixing frame 14 is connected to the support column 13; the electric push rod lifting mechanism 2 comprises a housing and a DC motor, a gear reduction assembly, and a screw arranged in the housing, and the DC motor is connected to the housing through the gear reduction assembly It is connected to the screw transmission, and the DC motor can drive the screw to rise and fall when it rotates; the shell is installed at the second end of the fixing frame 14 and is located above the bearing plate 12; the electric skull drill 3 is installed at the bottom end of the screw and the drill bit faces the bearing plate 12, and the power connection end of the driving motor of the electric skull drill 3 is connected to the AMR magnetoresistive current sensor; a single-chip microcomputer is arranged in the control box 4, and the single-chip microcomputer is electrically connected to the AMR magnetoresistive current sensor, the DC motor, and the driving motor respectively, and receives the current of the driving motor detected by the AMR magnetoresistive current sensor, and controls the start and stop of the DC motor and the electric skull drill 3.

[0029] In the self-stopping mini rat skull drill of the embodiment of the utility model, the electric skull drill 3 can be a miniature DC drill driven by a DC motor, and the rotation of the drill bit of the electric skull drill 3 can be controlled by controlling the start and stop of the DC motor. Since the skull drill is subjected to different resistances when penetrating different bone layers, different resistances will cause the torque of the skull drill to change, and the current of the driving motor of the skull drill is proportional to the torque. Based on this principle, the utility model detects the current of the driving motor of the electric skull drill 3 through an AMR magnetoresistive current sensor, and can further determine whether the drill bit has penetrated the skull according to whether the detected current has changed and the change situation, thereby conveniently and timely controlling the skull drill to stop rotating, and realizing automatic stop control of the skull drill.

[0030] According to an exemplary embodiment of the utility model, the bracket 1 is used to support the electric push rod lifting mechanism 2 and the electric skull drill 3 and to carry experimental animals. Specifically, the carrying plate 12 can be horizontally arranged above the base 11 to carry experimental animals; the support column 13 can be installed on one side of the carrying plate 12, and the fixing frame 14 is installed on the support column 13, so that the electric push rod lifting mechanism 2 and the electric skull drill 3 installed on the fixing frame 14 can be located directly above the carrying plate 12, which is convenient for operating the experimental animals.

[0031] Optionally, the support column 13 is rotatably arranged on the bearing plate 12, so as to facilitate adjusting the position of the electric skull drill 3 by rotation; and a second limiting structure is arranged at the rotation connection of the support column 13, so as to lock the support column 13. Here, the rotation mode of the support column 13 can be Figure 2 The support column 13 shown in the figure is rotatably connected to the carrier plate 12; it can also be a two-section structure in which the support column is fixedly connected to the carrier plate and the support column is rotatable, the upper section is rotatably arranged at the top of the lower section, the lower section is fixedly connected to the carrier plate, and the upper section is connected to the fixed frame. Accordingly, the second limiting structure can be set according to the specific rotation method. For example, the second limiting structure can include a clamping strip hinged at the rotating end and a ring member installed at the fixed end and having a corrugated groove. When the support column is rotated to make the electric skull drill on the fixed frame face the experimental animal, the support column can be locked by operating the clamping strip to rotate until the corrugated groove is stuck.

[0032] Optionally, the fixing frame 14 includes a retractable upper push-pull rod and a lower push-pull rod, the first ends of the upper and lower push-pull rods are connected to the support column 13, and the second ends have connecting parts such as mounting grooves and connecting holes for connecting to the housing of the electric push rod lifting mechanism 2; the upper push-pull rod and the lower push-pull rod are provided with a first limiting structure for locking the upper push-pull rod and the lower push-pull rod. When the test starts, the operator can extend and retract the upper and lower push-pull rods by pushing and pulling operations, so that the electric push rod lifting mechanism 2 can adjust the position in the extension direction of the push-pull rods. For example, the upper and lower push-pull rods can be composed of two sections of steel pipes of different specifications, and the first limiting structure can include a clamping strip hinged on the fixed tube, a strip groove opened on the telescopic tube, and a plurality of tooth-shaped protrusions arranged in the groove. When the upper and lower push-pull rods are extended and retracted to make the electric skull drill 3 face the experimental animal, the limit locking of the push-pull rod can be achieved by operating the clamping strip to rotate until the tooth-shaped protrusion is stuck.

[0033] The electric push rod lifting mechanism 2 is used to drive the electric skull drill 3 to rise and fall. Specifically, the output shaft of the DC motor is connected to the driving gear of the gear reduction assembly, the driving gear is meshed with the driven gear, and the driven gear is connected to the screw nut (the nut can be installed at the center of the driven gear so that the screw passes through the nut and the driven gear). When the DC motor is started, the gear reduction assembly and the screw convert the rotation into the up and down linear motion of the screw, thereby driving the electric skull drill 3 to rise and fall. It is explained here that the rat skull drill of this embodiment is a micro drill, and the electric skull drill used is a micro DC drill. Correspondingly, the DC motor, gear reduction assembly, screw and other components included in the electric push rod lifting mechanism are also micro to ensure the miniaturization and portability of the overall structure. In addition, the electric skull drill is detachably connected to the bottom end of the screw, and the electric skull drill is a detachable drill bit, which is convenient for operators to replace the electric skull drill or replace the drill bit according to different experimental requirements. Figure 1 and Figure 2 The electric skull drill 3 shown in the figure is located inside the housing of the electric push rod lifting mechanism 2. The operator can replace the drill bit by extending the drill bit out of the housing when the electric push rod lifting mechanism 2 descends.

[0034] Optionally, the electric push rod lifting mechanism further includes a travel switch assembly, including an upper and lower travel switch and a stopper, wherein the upper and lower travel switches are respectively arranged at the upper part and the middle and lower part of the housing, and the stopper is arranged on the lead screw and is located between the upper and lower travel switches. During the up and down movement of the lead screw, the stopper moves up and down with the lead screw, and when the stopper touches the upper travel switch or the lower travel switch, the upper travel switch or the lower travel switch is actuated to stop the DC motor from rotating.

[0035] The single chip microcomputer in the control box 4 is electrically connected to the AMR magnetoresistive current sensor, the DC motor, and the drive motor through wiring. Figure 4As shown, the single-chip microcomputer is electrically connected to the AMR magnetoresistive current sensor through a signal processing circuit (which may include an A / D converter, a signal amplifier, a filter, etc.); the AMR magnetoresistive current sensor may be composed of a dedicated magnetoresistive current measurement chip and a peripheral processing circuit. A U-shaped conductor with a rectangular cross section is installed on the back of the ceramic substrate. When the current to be detected flows through the conductor, a magnetic field parallel to its surface is generated on the front printed circuit board. The magnetoresistive current measurement chip can measure the magnetic field generated by the current through the magnetoresistive element and output a corresponding induction signal, thereby realizing the measurement of the measured current. The signal is input into the single-chip microcomputer after amplification, noise reduction, A / D conversion, etc.

[0036] The single-chip microcomputer is electrically connected to the DC motor of the electric push rod lifting mechanism through a driver chip (such as a TA7267BP chip), and is electrically connected to the drive motor (micro DC motor) of the electric skull drill through a DC motor driver (such as an L298N driver). The single-chip microcomputer outputs PWM logic control signals to the driver chip / DC motor driver to control the start and stop and forward and reverse rotation of the motor. Based on PWM control, frequent stepless rapid starting and rapid braking can be achieved, and the single-chip microcomputer and DC motor can be prevented from being damaged.

[0037] In an optional implementation, after receiving the current data of the electric skull drill detected by the AMR magnetoresistive current sensor, it is determined whether the skull layer is drilled through according to the current change. Figure 5 and Figure 6 As shown in the figure, during the bone grinding process, the drill bit receives different resistance from different bone layers, and the corresponding detected current is different; and each time a bone layer is drilled through, the current will step. The single-chip microcomputer monitors the current change in real time, selects the maximum current, and subtracts the current value from the maximum current to obtain the current difference. When the current difference is greater than the set value, it is judged as penetrating one side; when the number of penetrations is 3, the skull is about to be drilled through. At this time, the next step is to determine the appropriate drilling. When the difference between the current values ​​of two adjacent time points is close to 0, that is, when the current change curve is close to a straight line over a period of time, it is judged that the skull is penetrated. Here, the set value of the current difference and the minimum current value can be determined according to the actual experimental conditions and experience.

[0038] After the single-chip microcomputer processes the current signal detected by the AMR magnetoresistive current sensor and determines that the skull layer is drilled through, it can send a shutdown control signal to the drive motor to achieve automatic and timely shutdown of the electric skull drill; and it can send an ascending control signal to the DC motor of the electric push rod lifting mechanism to make the electric push rod lifting mechanism drive the skull drill to ascend.

[0039] In this embodiment, Figure 1 and Figure 7As shown, the control box 4 is provided with a plurality of operation buttons, including a start button, a stop button, a forward button, and a reverse button, and the single chip microcomputer can be electrically connected to the plurality of operation buttons through a mode switching circuit. The operator can enter the automatic control mode by clicking the start button, so that the electric push rod lifting mechanism 2 starts to descend, and the drill bit of the electric skull drill 3 starts to rotate until the skull is penetrated (the detected current value is less than the set minimum current value), the single chip microcomputer controls the drill bit of the electric skull drill to stop rotating, and controls the electric push rod lifting mechanism 2 to rise at the same time; here, if you want to start again, you need to click the start button repeatedly. In this process, the operator can stop the lifting mechanism by clicking the stop button and enter the manual control mode. In the manual control mode, the operator can control the lifting mechanism to drive the skull drill to rise and fall respectively through the motor forward button (rise) and reverse button (fall), and can stop the rise and fall at any time by the motor stop button. In addition, the control box 4 is also provided with a plurality of indicator lights, including a start indicator light, a stop indicator light, a forward indicator light, and a reverse indicator light. When the operator presses any button of the motor, the corresponding indicator light is on; and a switch button can be provided on the control box 4 to facilitate the start of the control device. The operator can switch the automatic mode according to the actual situation, and the experimental process can be completed by only clicking the operation button, which is simple to operate.

[0040] In actual application scenarios, each electrical component in the self-stop micro rat cranial drill based on the AMR magnetoresistive current sensor of the embodiment of the utility model can adopt devices with corresponding functions in the prior art; for example, the STM32 series single-chip microcomputer (STM32F103), which has high integration and high performance, and can realize the data communication and data processing control functions of the above-mentioned single-chip microcomputer at a relatively low cost.

[0041] Furthermore, other devices or components may be provided in the self-stopping micro rat cranial drill, or the actual installation positions of the devices or components may be adjusted to realize the practical application or other functions of the self-stopping micro rat cranial drill based on the AMR magnetoresistive current sensor. For example, a calibration component (which may include Figure 2 The horizontal gyroscope 15 shown in the figure is arranged on the top of the electric push rod lifting mechanism). When the equipment is used for a long time and the machine lifting may cause the drill bit to be no longer vertical, it can be adjusted according to the calibration component. For another example, it also includes a power supply component and a communication component. The power supply component is used to power the various electrical components in the self-stopping mini rat cranial drill, and the communication component is used to realize the communication connection between the various electrical components in the self-stopping mini rat cranial drill.

[0042] It should be pointed out that, according to the needs of implementation, the various components described in the embodiments of the present utility model can be split into more components, or two or more components or parts of components can be combined into new components to achieve the purpose of the embodiments of the present utility model.

[0043] The above-mentioned embodiments only express several implementation methods of the utility model, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the patent of the utility model. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the utility model, and these all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

Claims

1. A self-stopping mini rat cranial drill based on AMR magnetoresistive current sensor, characterized in that: include: The bracket comprises a base, a bearing plate, a support column and a fixing frame, wherein the bearing plate is fixed above the base, the support column is arranged on the bearing plate, and a first end of the fixing frame is connected to the support column; The electric push rod lifting mechanism comprises a housing and a DC motor, a gear reduction assembly, and a screw rod arranged in the housing. The DC motor is connected to the screw rod through the gear reduction assembly, and the DC motor can drive the screw rod to rise and fall when it rotates; the housing is installed at the second end of the fixing frame and is located above the bearing plate; An electric skull drill is installed at the bottom end of the screw rod with the drill head facing the bearing plate, and the power connection end of the driving motor of the electric skull drill is connected to an AMR magnetoresistive current sensor; A control box is provided with a single-chip microcomputer, which is electrically connected to the AMR magnetoresistive current sensor, the DC motor, and the drive motor respectively, and receives the current of the drive motor detected by the AMR magnetoresistive current sensor, and controls the start and stop of the DC motor and the electric skull drill.

2. The self-stopping mini rat cranial drill based on AMR magnetoresistive current sensor according to claim 1, characterized in that: The electric push rod lifting mechanism also includes a travel switch assembly, including upper and lower travel switches and a stopper, the upper and lower travel switches are respectively arranged in the upper part and the middle and lower part of the shell, and the stopper is arranged on the screw rod and located between the upper and lower travel switches.

3. The self-stopping mini rat cranial drill based on AMR magnetoresistive current sensor according to claim 1, characterized in that: The control box is provided with a plurality of operation buttons, including a start button, a stop button, a forward button, and a reverse button, and the single chip microcomputer is electrically connected to the plurality of operation buttons respectively.

4. The self-stopping mini rat cranial drill based on AMR magnetoresistive current sensor according to claim 3, characterized in that: The control box is provided with a plurality of indicator lights, including a start indicator light, a stop indicator light, a forward indicator light, and a reverse indicator light.

5. The self-stopping mini rat cranial drill based on AMR magnetoresistive current sensor according to claim 1, characterized in that: The fixing frame comprises a retractable upper push-pull rod and a lower push-pull rod, and the upper push-pull rod and the lower push-pull rod are provided with a first limiting structure for locking the upper push-pull rod and the lower push-pull rod.

6. The self-stopping mini rat cranial drill based on AMR magnetoresistive current sensor according to claim 1, characterized in that: The support column is rotatably arranged on the bearing plate, and a second limiting structure is arranged at the rotation connection of the support column for locking the support column.

7. The self-stopping mini rat cranial drill based on AMR magnetoresistive current sensor according to claim 1, characterized in that: The device also includes a calibration component, which is a horizontal gyroscope and is arranged on the top of the electric push rod lifting mechanism.

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