CN117379090A

CN117379090A - Bone mineral density measuring part marking device

Info

Publication number: CN117379090A
Application number: CN202311482738.1A
Authority: CN
Inventors: 季伯伦; 杜鼎铭
Original assignee: Xuzhou Pinyuan Electronic Technology Co ltd
Current assignee: Xuzhou Pinyuan Electronic Technology Co ltd
Priority date: 2023-11-09
Filing date: 2023-11-09
Publication date: 2024-01-12

Abstract

The application discloses bone density measurement position marking device, which comprises a shell, a first driving mechanism, a marking ruler, a connecting component, a second driving mechanism, a limiting component, a locking mechanism, a ranging component and a controller, wherein a first through groove and a second through groove are formed in the shell, a rod body is arranged on the shell, and one end of the rod body extends into the shell; the first driving mechanism is arranged on the shell, the moving end of the first driving mechanism is arranged in the shell and is fixedly connected with the marking ruler, and one end of the first driving mechanism is connected with the connecting component; one end of the marking ruler, which is far away from the first driving mechanism, penetrates through the second through groove; the connecting component is rotationally connected in the shell and is meshed with the second driving mechanism; the second drive mechanism is disposed in the housing. Therefore, the radius length can be accurately measured, the position of the 1/3 position of the distal end of the radius can be automatically indicated, accurate and rapid measurement is realized, time and labor are saved, and the influence of human errors on the measurement result is avoided.

Description

Bone mineral density measuring part marking device

Technical Field

The application relates to the technical field of medical instruments, in particular to a bone mineral density measuring position marking device.

Background

In recent years, bone density detection has become an important tool for medical diagnosis, and by measuring bone content, doctors can evaluate the risk of osteoporosis, fracture risk, and other bone diseases. However, to obtain accurate bone density measurements, it is critical to ensure the selection of the measurement site. Bone density measurement based on ultrasonic axial conduction technology generally selects long bones such as radius, tibia and the like as measurement objects. When measuring the radius, clinical studies in the medical industry typically use 1/3 of the distal radius as the measurement site.

Referring to fig. 5, conventionally, when a doctor performs a measurement, a distance from a protrusion on one side of a forearm near a wrist to a joint of the forearm is measured using a ruler to determine a length of a radius, and a position distance of 1/3 of a distal radius is calculated according to the measurement result. Next, the position 1/3 of the distal radius is marked with a pen as a measurement site to ensure that the probe is placed in the correct position. However, since the physical form and bone structure of each individual are different, a doctor often makes an artificial error in taking the measurement, resulting in an influence on the accuracy of the measurement result. In addition, this kind of operation is comparatively loaded down with trivial details, wastes time and energy.

Disclosure of Invention

The present application aims to solve, at least to some extent, one of the technical problems in the related art.

Therefore, an object of the present application is to provide a bone mineral density measurement position marking device, which can accurately measure the length of the radius, and can automatically indicate the position of the 1/3 position of the distal end of the radius, thereby realizing accurate and rapid measurement, saving time and labor and avoiding the influence of human errors on the measurement result.

To achieve the above objective, an embodiment of a first aspect of the present application provides a bone density measurement site marking device, which includes a housing, a first driving mechanism, a marking ruler, a connecting component, a second driving mechanism, a limiting component, a locking mechanism, a ranging component and a controller, wherein the housing is provided with a first through slot and a second through slot, the housing is provided with a rod body, and one end of the rod body extends into the housing; the first driving mechanism is arranged on the shell, the moving end of the first driving mechanism is arranged in the shell and is fixedly connected with the marking ruler, one end of the first driving mechanism is connected with the connecting assembly, and the first driving mechanism is used for driving the marking ruler to move and driving the connecting assembly to rotate; one end of the marking ruler, which is far away from the first driving mechanism, penetrates through the second through groove, and the marking ruler is used for indicating a part measured by the bone densitometer; the connecting component is rotationally connected in the shell and is meshed with the second driving mechanism; the second driving mechanism is arranged in the shell, one end of the second driving mechanism is fixedly connected with the limiting assembly, and the second driving mechanism is used for driving the limiting assembly to move; one end of the limiting component is slidably connected in a first sliding groove formed in the bottom wall of the inner part of the shell, the other end of the limiting component penetrates through the first through groove and extends to the outer part of the shell, and the limiting component is used for limiting the wrist of a patient and used as a starting point of measurement; the locking mechanism is arranged in the limiting assembly and used for locking the second driving mechanism; one end of the ranging component is connected with the rod body, the other end of the ranging component is connected with the limiting component, and the ranging component is used for measuring the length of the radius of a patient so as to obtain the length of the radius; the controller is arranged in the shell, and is respectively connected with the first driving mechanism and the distance measuring assembly, and the controller is used for controlling the first driving mechanism according to the radius length.

According to the bone mineral density measuring position marking device, the radius length can be accurately measured, the position of the 1/3 position of the distal end of the radius can be automatically indicated, accurate and rapid measurement is realized, time and labor are saved, and the influence of human errors on the measurement result is avoided.

In addition, the bone mineral density measuring site marking device according to the present application may further have the following additional technical features:

in one embodiment of the present application, the first driving mechanism includes a motor, a first screw rod and a first ball nut pair, where the motor is disposed on the housing, and an output shaft of the motor penetrates through a side wall of the housing and is fixedly connected with the first screw rod, and the other end of the first screw rod is fixedly connected with the connection component; the first ball nut pair is in threaded connection with the outer wall of the first screw rod; the marking ruler is fixed on the outer wall of the first ball nut pair.

In one embodiment of the present application, the connecting assembly includes a torsion limiter, a connecting rod and a first gear, wherein one end of the connecting rod is connected with one end of the first screw rod through the torsion limiter, and the other end of the connecting rod is rotatably connected with the housing; the first gear is fixedly connected to the outer wall of the connecting rod.

In one embodiment of the present application, the second driving mechanism includes a second screw rod, a second ball nut pair and a second gear, where one end of the second screw rod is in threaded connection with the second ball nut pair, and the other end of the second screw rod is fixedly connected with the limiting component; the second ball nut pair is rotationally connected with the shell; the second gear is arranged on the outer wall of the second ball nut pair, and the second gear is meshed with the first gear.

In one embodiment of the present application, the limiting component includes two arc plates, a tube body and a fixed block, wherein the fixed block is slidably connected in the first chute, a cavity is arranged inside the fixed block, and two openings are symmetrically arranged on the surface of the fixed block; one end of the pipe body is fixed on the fixed block, and the other end of the pipe body penetrates through the first through groove; the two arc plates are respectively arranged on the outer wall of the pipe body through torsion springs.

In one embodiment of the present application, a second roller is rotatably connected in a notch formed in the arcuate plate.

In one embodiment of the present application, the locking mechanism includes a compression bar, a ferrule, a first spring and a second spring, a conical cylinder, two L-shaped plates, two first rollers and two sliding blocks, wherein the compression bar is arranged in the pipe body, one end of the compression bar penetrates through the top wall of the fixed block and is fixedly connected with the conical cylinder, and the other end of the compression bar extends to the outside of the pipe body; the first spring is arranged in the pipe body, one end of the first spring is fixedly connected with the ferrule, and the other end of the first spring is fixed on the fixed block; the ferrule is fixed on the outer wall of the compression bar, and the ferrule slides in the pipe body; the conical cylinder, the L-shaped plate, the first roller and the sliding block are respectively arranged in the cavity; the outer wall of the conical cylinder is abutted against two first rollers, the two first rollers are respectively connected to the corresponding L-shaped plates in a rotating mode, the two L-shaped plates are respectively fixed on the corresponding sliding blocks, and the L-shaped plates face the corresponding openings respectively; the two sliding blocks are respectively and slidably connected in a second sliding groove arranged in the cavity; the second spring is arranged between the two sliding blocks.

In an embodiment of the application, the range finding subassembly includes extension spring and tension sensor, wherein, the one end of extension spring is fixed on the stick body, the other end of extension spring with tension sensor links to each other, tension sensor keeps away from the one end setting of extension spring is in on the outer wall of body.

Additional aspects and advantages of the application will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the application.

Drawings

The foregoing and/or additional aspects and advantages of the present application will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a schematic structural view of a bone mineral density measurement site marking device according to one embodiment of the present application;

FIG. 2 is a schematic view of the structure of the interior of a housing according to one embodiment of the present application;

FIG. 3 is a schematic view of a locking mechanism according to one embodiment of the present application;

FIG. 4 is a schematic structural view of a bone mineral density measurement site marking device according to another embodiment of the present application;

fig. 5 is a schematic diagram of a marker measuring site in the prior art for bone mineral density measurement.

As shown in the figure: 1. a housing; 2. a first driving mechanism; 3. marking a ruler; 4. a connection assembly; 5. a second driving mechanism; 6. a limit component; 7. a locking mechanism; 8. a ranging assembly; 9. a controller; 10. a first through groove; 11. a rod body; 12. a first chute; 13. a cover; 14. a second through slot; 20. a motor; 21. a first screw rod; 22. a first ball nut pair; 40. a torsion limiter; 41. a connecting rod; 42. a first gear; 51. a second screw rod; 52. a second ball nut pair; 53. a second gear; 60. an arc-shaped plate; 61. a tube body; 62. a fixed block; 70. a compression bar; 71. a ferrule; 72. a first spring; 73. a second spring; 74. a conical cylinder; 75. an L-shaped plate; 76. a first roller; 77. a slide block; 80. a tension spring; 81. a tension sensor; 600. a second roller; 620. a cavity; 621. an opening; 622. and a second chute.

Detailed Description

Embodiments of the present application are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary and intended for the purpose of explaining the present application and are not to be construed as limiting the present application. On the contrary, the embodiments of the present application include all alternatives, modifications, and equivalents as may be included within the spirit and scope of the appended claims.

The bone density measuring site marking device according to the embodiment of the present application is described below with reference to the accompanying drawings.

The bone mineral density measurement position marking device provided by the embodiment of the application can be used for measuring the length of the radius, and can automatically indicate the position of the 1/3 position of the distal end of the radius, so that accurate and rapid measurement is realized, time and labor are saved, and the influence of human errors on the measurement result is avoided.

As shown in fig. 1-4, the bone mineral density measuring site marking device according to the embodiments of the present application may include a housing 1, a first driving mechanism 2, a marking ruler 3, a connecting assembly 4, a second driving mechanism 5, a limiting assembly 6, a locking mechanism 7, a ranging assembly 8, and a controller 9.

Wherein, first logical groove 10 and second logical groove 14 have been seted up on the casing 1, be provided with the body 11 on the casing 1, and the one end of body 11 extends to the inside of casing 1, wherein, can understand that the patient is crooked with the arm for the joint department parcel body 11 of arm utilizes body 11 to put the posture to the patient's arm and plays a spacing effect, cooperates spacing subassembly 6 simultaneously and can play spacing effect to the arm and put the posture, and then guaranteed the accuracy when measuring.

It should be noted that, the front surface of the housing 1 described in this embodiment is provided with an opening, which facilitates maintenance of the electrical components inside the housing 1.

As a possible case, in order to increase the aesthetic appearance of the present bone mineral density measuring site marking device and protect the electrical components inside the case 1, a case cover 13 may be attached to the opening.

The first actuating mechanism 2 sets up on casing 1, the mobile end of first actuating mechanism 2 is arranged in casing 1 and with mark chi 3 fixed connection, and the one end of first actuating mechanism 2 links to each other with coupling assembling 4, first actuating mechanism 2, be used for driving mark chi 3 and remove and drive coupling assembling 4 rotation, mark chi 3 keeps away from the one end of first actuating mechanism 2 and runs through second through groove 14, mark chi 3, be used for instructing bone densitometer measuring position, coupling assembling 4 rotates and connects in casing 1, and coupling assembling 4 and second actuating mechanism 5 meshing are connected, second actuating mechanism 5 sets up in casing 1, and the one end and the spacing subassembly 6 fixed connection of second actuating mechanism 5, be used for driving spacing subassembly 6 and remove, spacing subassembly 6's one end sliding connection is in the first spout 12 of seting up on casing 1 inside diapire, spacing subassembly 6 other end runs through first through the outside of casing 1, be used for spacing to patient's wrist, and as the initial point of measuring, locking mechanism 7 sets up in spacing subassembly 6, be used for carrying out distance measuring to second actuating mechanism 5, the one end of locking mechanism 8 and distance measuring subassembly 8, the distance measuring subassembly 8 is used for obtaining the length of radius 8 with the radius 8, the distance measuring subassembly is connected with the other end of radius 8, the distance measuring assembly is used for obtaining the distance measuring assembly 8.

It should be noted that the radius length described in this embodiment refers to the distance from the protrusion near the wrist side to the forearm joint.

A controller 9 is arranged in the housing 1, and the controller 9 is connected to the first drive mechanism 2 and the distance measuring assembly 8, respectively, and the controller 9 is used for controlling the first drive mechanism 2 according to the radius length.

It should be noted that, the controller 9 described in this example may communicate with an external upper computer in a wired or wireless manner, so as to receive an instruction sent by the upper computer and control the operation of a device connected with the controller according to the instruction, where the controller 9 may include a control panel, and a display screen and function keys are disposed on the control panel, so that a related person can conveniently view the data of the running bone mineral density measuring position marking device through the display screen, and can conveniently adjust and modify the data through the input keys.

Specifically, when this bone mineral density measurement position marker device of in-service use, at first the patient is crooked with the arm, make the joint department parcel stick body 11 of arm, make the arm drop down slowly and place the putting down simultaneously, at the in-process of putting down slowly, the relevant personnel is through starting first actuating mechanism 2, first actuating mechanism 2 moves drive coupling assembling 4 and drives second actuating mechanism 5 operation, make second actuating mechanism 5 drive spacing subassembly 6 remove, make spacing subassembly 6 can be in wrist department (i.e. the protruding department of wrist one side) when the arm drops, then close first actuating mechanism 2, the arm drops and makes wrist department block into spacing subassembly 6, press on locking mechanism 7, promote locking mechanism 7 and move down, locking mechanism 7 carries out the lock to second actuating mechanism 5 at this moment, and range finding subassembly 8 can measure patient's radius length, and send the length of the bone that obtains to controller 9, controller 9 calculates the position of corresponding bone distal end 1/3 department, and start first actuating mechanism 2, make first actuating mechanism 2 drop down makes wrist department block into spacing subassembly 6, thereby the second actuating mechanism 5 can not be used for measuring the position of the distal end 1, when the radial end 1 carries out the measuring mechanism, and the position of radius 5 is difficult to confirm the measuring situation, thereby the second actuating mechanism is difficult to appear, and the measuring mechanism is moved, the position of the distal end 1 is measured, and the position of the distal end is measured, and the position of the distal end 1 is difficult to be measured, and the position is convenient for the position of the distal end 1 is measured, and the distal end is measured.

In one embodiment of the present application, as shown in fig. 2, the first driving mechanism 2 may include a motor 20, a first screw 21, and a first ball nut pair 22.

Wherein, motor 20 sets up on casing 1, and the output shaft of motor 20 runs through the lateral wall of casing 1 and first lead screw 21 fixed connection, and first lead screw 21's the other end and coupling assembling 4 fixed connection, first ball nut pair 22 threaded connection is on first lead screw 21 outer wall, and mark chi 3 is fixed on first ball nut pair 22's outer wall.

It should be noted that, the motor 20 described in this embodiment is a stepper motor with an encoder, the rotation angle of the stepper motor is obtained by the encoder and sent to the controller 9, so that the controller 9 determines the position of the first ball nut pair 22 (i.e. the position of the marking ruler 3) according to the rotation angle, and then the controller 9 can precisely control the moving distance of the first ball nut pair 22 by controlling the frequency and the pulse number of the pulse signal according to the measured radius length.

In one embodiment of the present application, as shown in fig. 2, the connection assembly 4 may include a torsion limiter 40, a connection rod 41, and a first gear 42.

One end of the connecting rod 41 is connected with one end of the first screw 21 through the torsion limiter 40, the other end of the connecting rod 41 is rotatably connected with the housing 1, and the first gear 42 is fixedly connected on the outer wall of the connecting rod 41.

It should be noted that, the torque limiter 40 described in this embodiment has the main function of overload protection, and the torque limiter 40 limits the torque transmitted by the connecting rod 41 in a slipping manner when the required torque exceeds the set value due to overload, and automatically restores the connection after the overload condition is eliminated.

Specifically, the output shaft of the motor 20 drives the first ball nut pair 22 to rotate, drives the first ball nut pair 22 to move, and simultaneously drives the torsion limiter 40 to cooperate with the connecting rod 41 to drive the first gear 42 to rotate, so as to drive the second driving mechanism 5 to rotate, when the locking mechanism 7 locks the second driving mechanism 5, the second driving mechanism 5 does not rotate, the first gear 42 rotates, overload can be generated, so that the torsion limiter 40 is in a slipping condition, and therefore, when the position of the marking ruler 3 is adjusted, only the position of the marking ruler 3 is moved, the second driving mechanism 5 does not rotate, and the stability of the limiting assembly 6 is further ensured.

In one embodiment of the present application, as shown in fig. 2, the second driving mechanism 5 may include a second screw 51, a second ball nut pair 52, and a second gear 53.

One end of the second screw rod 51 is in threaded connection with the second ball nut pair 52, the other end of the second screw rod 51 is fixedly connected with the limiting assembly 6, and the second ball nut pair 52 is in rotary connection with the shell 1; the second gear 53 is provided on the outer wall of the second ball nut pair 52, and the second gear 53 is engaged with the first gear 42.

Specifically, when the position of the limiting component 6 is adjusted, the first driving mechanism 2 drives the connecting component 4 to operate, and the first gear 42 drives the second gear 53 to rotate, so as to drive the second ball nut pair 52 to rotate, and further drive the second screw rod 51 to drive the limiting component 6 to move.

In one embodiment of the present application, as shown in fig. 2, the spacing assembly 6 includes two arcuate plates 60, a tube 61, and a fixed block 62.

The fixed block 62 is slidably connected in the first chute 12, a cavity 620 is disposed inside the fixed block 62, two openings 621 are symmetrically disposed on the surface of the fixed block 62, one end of the tube 61 is fixed on the fixed block 62, the other end of the tube 61 penetrates through the first through slot 10, and two arc plates 60 are respectively disposed on the outer wall of the tube 61 through torsion springs (not labeled in the drawing).

Specifically, the wrist is clamped between the two arc plates 60, the arc plates 60 are spread, and the arc plates 60 generate reverse extrusion force under the action of the torsion spring to limit the wrist.

In order to further clearly illustrate the above embodiment, in one embodiment of the present application, as shown in fig. 1, the notch formed on the arc plate 60 is rotatably connected with the second roller 600, where it can be understood that by providing the second roller 600, when the wrist is clamped between the two arc plates 60, the wrist is first contacted with the second roller 600, and the second roller 600 rolls and is attached, so that the comfort during clamping can be increased.

In one embodiment of the present application, as shown in fig. 3, the locking mechanism 7 includes a plunger 70, a collar 71, first and second springs 72 and 73, a tapered cylinder 74, two L-shaped plates 75, two first rollers 76, and two sliders 77.

Wherein, the pressure lever 70 is arranged in the tube body 61, one end of the pressure lever 70 penetrates through the top wall of the fixed block 62 and is fixedly connected with the conical cylinder 74, and the other end of the pressure lever 70 extends to the outside of the tube body 61; the first spring 72 is disposed in the tube body 61, and one end of the first spring 72 is fixedly connected with the ferrule 71, and the other end of the first spring 72 is fixed on the fixed block 62; the ferrule 71 is fixed on the outer wall of the plunger 70, and the ferrule 71 slides in the tube body 61; the cone 74, the L-shaped plate 75, the first roller 76 and the slider 77 are respectively disposed in the cavity 620; the outer wall of the conical cylinder 74 is abutted against two first rollers 76, the two first rollers 76 are respectively connected to the corresponding L-shaped plates 75 in a rotating way, the two L-shaped plates 75 are respectively fixed on the corresponding sliding blocks 77, and the L-shaped plates 75 face the corresponding openings 621; the two sliding blocks 77 are respectively and slidably connected in a second sliding groove 622 arranged in the cavity 620; the second spring 73 is disposed between the two sliders 77.

It should be noted that, the material of the L-shaped plate 75 described in this embodiment may be silicon carbide ceramic, which has a higher friction coefficient, so that the friction between the L-shaped plate 75 and the second chute 622 can be increased, and the L-shaped plate 75 is designed in an L-shape, so that the contact area with the rod 50 can be increased, and the limiting force on the rod 50 can be further increased.

Specifically, when the wrist is pressed between the two arc plates 60, the wrist continues to press down, the pressing rod 70 is pushed to press the first spring 72 to push the conical cylinder 74 to move down, and the L-shaped plate 75 is pushed to abut against the second sliding groove 622 through the two first rollers 76, so that the fixed block 62 is limited, so that the fixed block 62 cannot move, and the second screw rod 51 is locked.

In one embodiment of the present application, as shown in fig. 2, the distance measuring assembly 8 may include a tension spring 80 and a tension sensor 81.

One end of the tension spring 80 is fixed on the rod 11, the other end of the tension spring 80 is connected with the tension sensor 81, and one end of the tension sensor 81 far away from the tension spring 80 is arranged on the outer wall of the tube 61.

Specifically, the length of the radius can be calculated by using the hogfennel root theory, namely, the extension (or shortening) amount of the tension spring is in direct proportion to the external force (tension) applied to the tension spring within the elastic limit, and the extension (or shortening) amount is expressed as follows: f=k×Δl.

Wherein F represents the external force applied by the tension spring, k represents the stiffness coefficient of the tension spring, and DeltaL represents the elongation (or shortening) amount of the tension spring.

A known tensile force F (which can be detected by the tension sensor 81) is applied to the tension spring, the elongation Δl of the tension spring is then measured, and finally the original length L0 of the tension spring can be determined by hooke's law: l0=Δl/k+l1, where L1 is the length of the tension spring before the pulling force F is applied, and the radius length is equal to the original length of the tension spring plus the elongation of the tension spring, so that calculation can be performed by the controller 9, so that the measured data is more accurate and rapid.

In sum, the bone mineral density measuring position marking device of the embodiment of the application can accurately measure the length of the radius, can automatically indicate the position of the 1/3 position of the distal end of the radius, realizes accurate and rapid measurement, saves time and labor, and avoids the influence of human errors on the measurement result.

In the description of this specification, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present application, the meaning of "plurality" is at least two, such as two, three, etc., unless explicitly defined otherwise.

In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present application. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, the different embodiments or examples described in this specification and the features of the different embodiments or examples may be combined and combined by those skilled in the art without contradiction.

While embodiments of the present application have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the present application, and that variations, modifications, alternatives, and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the present application.

Claims

1. A bone density measuring position marking device is characterized by comprising a shell, a first driving mechanism, a marking ruler, a connecting component, a second driving mechanism, a limiting component, a locking mechanism, a distance measuring component and a controller, wherein,

the shell is provided with a first through groove and a second through groove, a rod body is arranged on the shell, and one end of the rod body extends into the shell;

the first driving mechanism is arranged on the shell, the moving end of the first driving mechanism is arranged in the shell and is fixedly connected with the marking ruler, one end of the first driving mechanism is connected with the connecting assembly, and the first driving mechanism is used for driving the marking ruler to move and driving the connecting assembly to rotate;

one end of the marking ruler, which is far away from the first driving mechanism, penetrates through the second through groove, and the marking ruler is used for indicating a part measured by the bone densitometer;

the connecting component is rotationally connected in the shell and is meshed with the second driving mechanism;

the second driving mechanism is arranged in the shell, one end of the second driving mechanism is fixedly connected with the limiting assembly, and the second driving mechanism is used for driving the limiting assembly to move;

one end of the limiting component is slidably connected in a first sliding groove formed in the bottom wall of the inner part of the shell, the other end of the limiting component penetrates through the first through groove and extends to the outer part of the shell, and the limiting component is used for limiting the wrist of a patient and used as a starting point of measurement;

the locking mechanism is arranged in the limiting assembly and used for locking the second driving mechanism;

one end of the ranging component is connected with the rod body, the other end of the ranging component is connected with the limiting component, and the ranging component is used for measuring the length of the radius of a patient so as to obtain the length of the radius;

the controller is arranged in the shell, and is respectively connected with the first driving mechanism and the distance measuring assembly, and the controller is used for controlling the first driving mechanism according to the radius length.

2. The bone density measurement site marking apparatus as claimed in claim 1, wherein the first drive mechanism includes a motor, a first lead screw and a first ball nut pair, wherein,

the motor is arranged on the shell, an output shaft of the motor penetrates through the side wall of the shell and is fixedly connected with the first screw rod, and the other end of the first screw rod is fixedly connected with the connecting component;

the first ball nut pair is in threaded connection with the outer wall of the first screw rod;

the marking ruler is fixed on the outer wall of the first ball nut pair.

3. The bone density measurement site marking apparatus as claimed in claim 2, wherein the connection assembly includes a torsion limiter, a connecting rod and a first gear, wherein,

one end of the connecting rod is connected with one end of the first screw rod through the torsion limiter, and the other end of the connecting rod is rotationally connected with the shell;

the first gear is fixedly connected to the outer wall of the connecting rod.

4. The bone density measurement site marking apparatus as claimed in claim 3, wherein the second driving mechanism includes a second screw, a second ball nut pair and a second gear, wherein,

one end of the second screw rod is in threaded connection with the second ball nut pair, and the other end of the second screw rod is fixedly connected with the limiting assembly;

the second ball nut pair is rotationally connected with the shell;

the second gear is arranged on the outer wall of the second ball nut pair, and the second gear is meshed with the first gear.

5. The bone mineral density measurement site marking apparatus as claimed in claim 4, wherein the stop assembly comprises two arcuate plates, a tube and a fixed block, wherein,

the fixed block is connected in the first chute in a sliding way, a cavity is formed in the fixed block, and two openings are symmetrically formed in the surface of the fixed block;

one end of the pipe body is fixed on the fixed block, and the other end of the pipe body penetrates through the first through groove;

the two arc plates are respectively arranged on the outer wall of the pipe body through torsion springs.

6. The bone mineral density measurement site marking apparatus of claim 5 wherein a second roller is rotatably coupled to the arcuate plate in a recess formed therein.

7. The bone mineral density measurement site marking apparatus as claimed in claim 5, wherein the locking mechanism comprises a plunger, a collar, first and second springs, a cone, two L-shaped plates, two first rollers and two slides, wherein,

the pressure rod is arranged in the pipe body, one end of the pressure rod penetrates through the top wall of the fixed block and is fixedly connected with the conical cylinder, and the other end of the pressure rod extends to the outside of the pipe body;

the first spring is arranged in the pipe body, one end of the first spring is fixedly connected with the ferrule, and the other end of the first spring is fixed on the fixed block;

the ferrule is fixed on the outer wall of the compression bar, and the ferrule slides in the pipe body;

the conical cylinder, the L-shaped plate, the first roller and the sliding block are respectively arranged in the cavity;

the outer wall of the conical cylinder is abutted against two first rollers, the two first rollers are respectively connected to the corresponding L-shaped plates in a rotating mode, the two L-shaped plates are respectively fixed on the corresponding sliding blocks, and the L-shaped plates face the corresponding openings respectively;

the two sliding blocks are respectively and slidably connected in a second sliding groove arranged in the cavity;

the second spring is arranged between the two sliding blocks.

8. The bone density measurement site marking apparatus as claimed in claim 5, wherein the ranging assembly includes a tension spring and a tension sensor, wherein,

one end of the tension spring is fixed on the rod body, the other end of the tension spring is connected with the tension sensor, and one end of the tension sensor, which is far away from the tension spring, is arranged on the outer wall of the pipe body.