Joint protractor

Abstract

The utility model belongs to the technical field of medical instruments, and discloses a joint protractor, which comprises a dial, a fixed arm, a movable arm and a positioning piece, the fixed arm is fixed with the dial, the movable arm is rotatably connected onto the dial, and the linear projections of the movable arm and the fixed arm both pass through the center of the circle of the dial. The movable arm and the fixed arm are respectively connected with a positioning piece in a sliding mode, each positioning piece is provided with a limiting part, and the limiting parts are used for limiting the distance between the movable arm and the tested body and the distance between the fixed arm and the tested body. According to the joint protractor, through the positioning pieces arranged on the fixed arm and the movable arm, the influence of the bone shape on the fixed arm and the movable arm in the detection process is avoided, and therefore the detection accuracy of the joint protractor is improved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of medical apparatus and instruments, especially relates to a joint protractor. BACKGROUND

[0002] The joint protractor is a kind of medical apparatus and instruments for measuring joint range of motion (ROM), it can help to assess and monitor joint function, it is usually used in rehabilitation medicine, sports training, medical detection and forensic science inspection.The existing joint protractor generally includes fixed arm and moving arm, and dial, when measuring, fixed arm and moving arm are correspondingly pasted on the skeleton of both sides of joint and fixed, subject carries out the movement of joint, such as flexion, extension etc., to read the rotation angle according to the terminal position indicated on dial by moving arm, to show the range of motion of joint.However, the pasting condition of fixed arm and moving arm can be interfered by the shape of skeleton, influence the accuracy of measurement result. SUMMARY

[0003] In view of the problems in the prior art, the present application aims to provide a joint protractor, the joint protractor is always kept the distance between fixed arm and moving arm and skeleton by the positioning member arranged on fixed arm and moving arm, avoid the influence of the shape of skeleton on fixed arm and moving arm in detection process, to improve the detection accuracy of joint protractor.

[0004] In one aspect of the present application, a joint protractor is provided, comprising a dial;Fixed arm fixed to the dial, the fixed arm is parallel to the line of the plane where the dial is;Moving arm rotatably connected to the dial, the moving arm and the fixed arm are both projected on the straight line passing through the center of the circle where the dial is;Positioning member slidably connected to the same side of the moving arm and the fixed arm respectively, the positioning member has a limiting portion, the limiting portion is used to limit the distance between the moving arm and the fixed arm and the subject.

[0005] Preferably, the dial is marked with an angle scale for indicating the rotation angle of the moving arm.

[0006] More preferably, the range of the angle scale includes a first range and a second range marked in opposite directions, the upper and lower quadrants of the first range and the second range are both 0°-180°, and the first range and the second range share 0° line and 180° line, the fixed arm is fixed to the 0° line or 180° line of the dial.

[0007] Preferably, the moving arm extends an indicating portion, the indicating portion is rotatably connected to the dial by a rotating shaft.

[0008] More preferably, an accommodating groove perpendicular to the cross section of the moving arm is formed at the end of the indicating portion, and the dial is rotatably connected in the accommodating groove.

[0009] Preferably, the positioning member is provided with a through sliding hole, and the movable arm and the fixed arm are slidably connected with the positioning member through the sliding hole.

[0010] More preferably, the sliding hole is provided with a first guide surface, and the first guide surface has the same guide direction as the elongation direction of the movable arm and the fixed arm; the movable arm and the fixed arm are provided with a second guide surface matched with the first guide surface, and the second guide surface slides along the first guide surface.

[0011] Preferably, the movable arm and the fixed arm are respectively fixedly connected with a limiting block at the end away from the dial, so as to limit the sliding position of the positioning member.

[0012] Preferably, the joint protractor further comprises a fixing member, the fixing member is provided with a clamping part fixed to the subject, and the fixing member is detachably connected with the positioning member.

[0013] More preferably, the side of the positioning member facing the subject is provided with a clamping groove, and the side of the fixing member away from the clamping part is provided with an inserting part, and the inserting part is matchably inserted into the clamping groove.

[0014] Preferably, the joint protractor further comprises a supporting member, and the supporting member is detachably connected with the positioning member.

[0015] More preferably, the side of the positioning member facing the subject is provided with a clamping groove, and the supporting member is provided with an inserting part, and the inserting part is matchably inserted into the clamping groove.

[0016] The joint protractor has the advantages that:

[0017] The positioning member is arranged on the fixed arm and the movable arm, and the limiting part with a certain distance is reserved on the positioning member, the positioning member is located between the fixed arm, the movable arm and the subject to be measured during measurement, direct contact between the subject to be measured and the fixed arm and the movable arm is avoided, the influence of the special shape of the subject to be measured on the measurement result is eliminated, and the accuracy of the measurement result is improved. Meanwhile, the joint protractor has the characteristics of light structure, simple operation and convenient measurement. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a structural schematic view of the joint protractor of the utility model embodiment;

[0019] Figure 2 is a dial structure schematic view of the joint protractor of the utility model embodiment;

[0020] Figure 3 is an indication part structure schematic view of the joint protractor of the utility model embodiment;

[0021] Figure 4 is a positioning member structure schematic view of the joint protractor according to the embodiment of the present application;

[0022] Figure 5 is a sliding hole structure schematic view of the positioning member according to the embodiment of the present application;

[0023] Figure 6 is a structure schematic view of the fixed arm and the moving arm according to the embodiment of the present application;

[0024] Figure 7 is a fixed member structure schematic view of the joint protractor according to the embodiment of the present application;

[0025] Figure 8 is a bearing member structure schematic view of the joint protractor according to the embodiment of the present application;

[0026] Figure 9 is a structure schematic view of the joint protractor measuring the dorsal flexion of metacarpal joint according to the embodiment of the present application;

[0027] Figure 10 is a structure schematic view of the joint protractor measuring the dorsal extension of metacarpal joint according to the embodiment of the present application;

[0028] In the figure:

[0029] 1 - dial;

[0030] 2 - fixed arm, 21 - second guide surface;

[0031] 3 - moving arm, 31 - indication part, 311 - containing groove;

[0032] 4 - positioning member, 41 - limiting part, 42 - sliding hole, 43 - first guide surface, 44 - clamping groove;

[0033] 5 - limiting block;

[0034] 6 - fixed member, 61 - clamping part, 62 - plug-in part;

[0035] 7 - bearing member. DETAILED DESCRIPTION

[0036] Hereinafter, the example embodiments according to the present application will be described in detail with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application, and it should be understood that the present application is not limited to the example embodiments described herein.

[0037] Joint protractor is often used in medical detection and training rehabilitation of joints. The joint protractor can accurately measure the range of motion of the joint, helping doctors diagnose whether there is an abnormal condition of joint movement. In the direction of forensic clinical examination, the joint protractor is also needed to meet the measurement requirements in GA / T 1661-2019 "Standard for Forensic Examination of Joint Range of Motion" and SF / T 0111-2021 "Standard for Forensic Clinical Examination", so the accuracy of the joint range of motion has certain requirements. However, in forensic clinical examination, the flexion and extension range of motion of the metacarpophalangeal joint and the interphalangeal joint is often encountered. The joint protractor at the present stage does not consider the anatomical structure of the phalangeal tuberosity, and often interferes with the phalangeal tuberosity when measuring the function of the finger joint, affecting the accuracy of the measurement of the function of the finger joint. In order to eliminate the detection error existing for the phalangeal tuberosity, the present application designs a joint protractor.

[0038] In an embodiment of the present application, referring to Figure 1 A joint protractor is shown, which comprises a fixed arm 2, a moving arm 3, a scale disc 1 and a positioning piece 4. Wherein one end of the fixed arm 2 is fixed with the scale disc 1, and the extension line of the fixed arm 2 passes through the center of the scale disc 1, a rotating shaft is provided at the center of the scale disc 1, one end of the moving arm 3 is rotatably connected with the scale disc 1 through the rotating shaft, and the positioning piece 4 is slidably connected on the fixed arm 2 and the moving arm 3 respectively, the positioning piece 4 has a limiting part 41, which is used to control the space distance between the fixed arm 2 and the moving arm 3 and the subject. The fixed arm 2 and the moving arm 3 are respectively placed on the bones on both sides of the joint to be measured, the positioning piece 4 is respectively abutted with the bones on both sides, the positioning piece 4 is kept stationary relative to the measured bones, the positioning piece 4 plays a supporting role between the fixed arm 2, the moving arm 3 and the bones, so that the fixed arm 2 and the moving arm 3 have a certain distance from the bones, thereby avoiding the influence of the phalangeal tuberosity on the fixed arm 2 and the moving arm 3, and the supporting distance of the positioning piece 4 also ensures the distance between the scale disc 1 and the joint, avoiding the abutment between the joint and the scale disc 1 during the test, so that the joint cannot be further bent. In the bending process, the positioning piece 4 slides along the fixed arm 2 and the moving arm 3 with the movement of the joint, the positioning piece 4 is stationary relative to the joint, and the fixed arm 2 and the moving arm 3 move relative to the joint. In this dynamic process, the fixed arm 2 and the moving arm 3 can always be kept parallel relative to the bones on both sides of the joint, thereby achieving the purpose of accurate measurement; meanwhile, the positioning piece 4 connected to the fixed arm 2 and the moving arm 3 can be the same or different in structure, and different shapes are adopted to realize the fixation with the subject.

[0039] The fixed arm 2 is an arm that remains stationary relative to the dial 1, and the moving arm 3 is an arm that rotates relative to the dial 1. The moving arm 3 moves relative to the dial 1 to record the start and end positions, and the rotation angle of the moving arm 3, which is also the joint movement angle, can be obtained. The fixed arm 2 is fixed to the dial 1 to keep the fixed arm 2 stationary relative to the dial 1, and any fixing method that keeps the fixed arm 2 stationary relative to the dial 1 can be used, such as welding, bolting, bonding, buckling, magnetic fixing, and one-piece forming.

[0040] The dial 1 can be circular or semicircular, and is marked with an angle scale for indicating the rotation angle of the moving arm 3. The angle scale can be provided on the surface of the dial 1 or on the side circumferential surface of the dial 1.

[0041] The positioning member 4 has a sliding connection structure with the moving arm 3 and the fixed arm 2, and the sliding connection structure has a function of limiting the rotation of the positioning member 4 relative to the moving arm 3 and the fixed arm 2. The sliding connection structure can be realized by matching shapes of the sliding groove, the sliding hole 42, the moving arm 3, and the fixed arm 2, or a limiting structure for limiting rotation can be provided in the sliding groove or the sliding hole 42. In addition, in order to limit the distance between the moving arm 3 and the fixed arm 2 and the subject, the positioning member 4 is generally arranged between the fixed arm 2 and the moving arm 3 and the subject.

[0042] The limiting part 41 is used to limit the distance between the moving arm 3 and the fixed arm 2 and the subject. According to the actual measurement object, the distance can be limited by controlling the size of the limiting part 41. The distance at least needs to ensure that the moving arm 3, the fixed arm 2, and the dial 1 do not contact the corresponding bone in the full range of the moving arm 3. The limiting part 41 can be a part of the positioning member 4, such as an extension part of the positioning member 4 extending towards the subject, or other components connected to the positioning member 4. The shape and structure of the limiting part 41 are not required in this embodiment, and any structure that can achieve the technical purpose and occupies a certain space is suitable.

[0043] In order to prevent the positioning member 4 on the moving arm 3 and the fixed arm 2 from falling off, a limiting block 5 is arranged at the end of the moving arm 3 and the fixed arm 2 away from the dial 1. The limiting block 5 can be any geometric shape, and the connection between the limiting block 5 and the moving arm 3 and the fixed arm 2 can be one-piece forming or connecting a limiting block 5 to the moving arm 3 and the fixed arm 2 by bolting, riveting, welding, bolt, buckle, bonding, embedding, or the like.

[0044] In some embodiments, the dial 1 is a semicircular dial 1, and the fixed arm 2 is a semicircular fixed arm 2. Figure 2As shown, the dial 1 is selected as a circle, and the angular scale is arranged along the edge of the dial 1 in a circumferential direction, wherein the angular scale comprises a first range of 0° to 180° in the upper and lower quadrants, and a second range of 0° to 180° in the upper and lower quadrants, the first range and the second range are marked in opposite directions, wherein 0° and 180° are the starting point and the ending point of the first range and the second range. By marking the first range and the second range in opposite directions, the joint protractor is suitable for measuring in two directions at a time, that is, the user can complete the measurement in two directions at a time without additional operations, reducing the complexity of the operation; at the same time, without rotating the protractor to a specific position, the angles in two different directions can be intuitively read, improving work efficiency. The fixed arm 2 can be located at the 0° scale line, and the reading of the movable angle is read by the end of the moving arm 3 indicating; the fixed arm 2 can also be located at the 180° scale line, and the reading of the movable angle is read by the part of the moving arm 3 across the scale line.

[0045] In some embodiments, with reference to Figure 2 As shown, the end of the moving arm 3 is provided with an indicating part 31 in the direction of the long axis thereof, the indicating part 31 is rotatably connected through a rotating shaft passing through the center of the dial 1, and the moving arm 3 is rotatably connected with the dial 1 through the indicating part 31, wherein the shape and size of the moving arm 3 and the indicating part 31 are the same and are on the same straight line, and the end of the indicating part 31 away from the moving arm 3 has a gradually decreasing cross section. The arrangement of the indicating part 31 can facilitate clear pointing to the scale marks on the dial 1, avoid affecting the reading effect, or cause errors when reading. It can be understood that the moving arm 3 can be located on the surface of the dial 1, or have a coincident cross section with the plane on which the dial 1 is located.

[0046] In some embodiments, with reference to Figure 3 As shown, the end of the indicating part 31 away from the moving arm 3 is provided with a containing groove 311 perpendicular to the cross section of the moving arm 3, two side walls of the containing groove 311 form two pointers, the dial 1 is located in the containing groove 311, a rotating shaft passes through the two side walls of the containing groove 311 and the center of the dial 1 to rotatably connect the dial 1 with the containing groove 311, and the two pointers are located on the two sides of the dial 1, at this time, the angular scale can be arranged on the two sides of the dial 1 to facilitate reading from different directions, which is convenient for some special angle measurement or multi-person cooperation measurement scenarios.

[0047] In some embodiments, with reference to Figure 4As shown, the positioning member 4 is provided with a through sliding hole 42, and the moving arm 3 and the fixed arm 2 are slidably connected with the positioning member 4 through the sliding hole 42. The sliding hole 42 refers to a hole designed in a mechanical structure to realize the relative sliding between components. This hole allows the components to move along the axis of the hole, thereby realizing sliding connection. Sliding connection refers to the connection between two or more mechanical components in a way that allows them to slide relative to each other while maintaining a certain connection relationship. This connection allows the components to move relative to each other within a certain range while maintaining the stability of the structure.

[0048] Referring to Figure 5 As shown, in order to restrict the relative sliding and rotation of the moving arm 3 and the fixed arm 2, the sliding hole 42 has a first guide surface 43, which is a surface of the sliding hole 42 designed to guide the movement of the moving component in a specific direction. In this embodiment, the guide direction of the first guide surface 43 is the same as the elongation direction of the moving arm 3 and the fixed arm 2, which means that the first guide surface 43 is a surface inside the sliding hole 42 that provides guidance along the elongation direction of the moving arm 3 and the fixed arm 2. The first guide surface 43 ensures the accuracy and stability of the moving arm 3 and the fixed arm 2 when they slide in the sliding hole 42, preventing them from deviating from the predetermined movement path. The first guide surface 43 can be part of the inner wall of the sliding hole 42, or it can be a specially designed protrusion or groove inside the sliding hole 42 to accommodate the shape and sliding needs of the moving component. Figure 6 As shown, the moving arm 3 and the fixed arm 2 have a second guide surface 21 that cooperates with the first guide surface 43 and slides along the first guide surface 43. The second guide surface 21 is a surface on the moving arm 3 and the fixed arm 2 that cooperates with the first guide surface 43 to achieve sliding connection. In this embodiment, the second guide surface 21 is a surface on the moving arm 3 and the fixed arm 2 that contacts and slides along the first guide surface 43 inside the sliding hole 42. The design of the second guide surface 21 is usually matched with the first guide surface 43 to ensure smooth and accurate sliding. This matching relationship can reduce friction, improve sliding efficiency, and ensure the stability and reliability of the connected components during movement.

[0049] In some embodiments, referring to Figure 7 As shown, the joint protractor further includes a fixing member 6, which includes a clamping portion 61 and a plug-in portion 62. The clamping portion 61 and the plug-in portion 62 are fixedly connected back to back. The clamping portion 61 is used to fix with the subject, and can be any structure with clamping and fixing function. The plug-in portion 62 is used to slidably connect with the positioning member 4. Referring again to Figure 4As shown, the positioning member 4 is provided with a clamping groove 44 on the side facing the subject, and the insertion part 62 is matched and connected in the clamping groove 44, wherein the limiting part 41 is located between the sliding hole 42 and the clamping groove 44, for increasing the distance between the sliding hole 42 and the clamping groove 44. In use, the fixing member 6 is connected with the positioning member 4 by inserting the insertion part 62 into the clamping groove 44, and at this time, the clamping of the fixing member 6 can be used to fix the bones on both sides of the joint, so as to facilitate the next detection.

[0050] Referring to Figure 9 and Figure 10 As shown, taking the phalanges as an example, the positioning members 4 on the fixed arm 2 and the moving arm 3 are fixed on the dorsal sides of the proximal phalanges and the middle phalanges, or are respectively fixed on the dorsal sides of the middle phalanges and the distal phalanges during detection, and the fixed arm 2 and the moving arm 3 are kept parallel to the fixed phalanges respectively, so that the interphalangeal joint of the subject is flexed and stretched.

[0051] In some embodiments, referring to Figure 8 As shown, the joint protractor further comprises a supporting member 7, and the supporting member 7 is fixed with an insertion part 62 matched with the clamping groove 44 provided on the positioning member 4. In use, the insertion part 62 is inserted into the clamping groove 44 of the positioning member 4, so as to realize the fixed connection between the supporting member 7 and the positioning member 4.

[0052] Referring to Figure 9 and Figure 10 As shown, taking the phalanges as an example, the supporting member 7 is suitable for testing the function of the interphalangeal joint, and the moving arm 3 and the fixed arm 2 are respectively connected with the fixing member 6 and the supporting member 7. For example, the supporting member 7 is connected on the positioning member 4 of the fixed arm 2, and the fixing member 6 is connected on the positioning member 4 of the moving arm 3. The supporting member 7 is attached to the dorsal side of the metacarpal bone of the subject, and the fixed arm 2 is kept parallel to the attached metacarpal bone. The fixing member 6 on the moving arm 3 is fixed on the dorsal side of the proximal phalanges by the clamping part 61, and the moving arm 3 is kept parallel to the proximal phalanges, so that the metacarpophalangeal joint of the subject is flexed and stretched. It can be understood that the supporting member 7 needs to be pressed by the operator to realize the static state relative to the metacarpal bone due to the structure of the fixed metacarpal bone. In order to better measure, a bandage can be provided on the supporting member 7, and in use, the bandage is wound around the metacarpal bone for fixation.

[0053] Embodiment

[0054] Referring to Figure 1 and Figure 2As shown in the figure, a joint protractor comprises a fixed arm 2, a moving arm 3, a scale disc 1 and a positioning piece 4, wherein the fixed arm 2 is integrally formed with the scale disc 1, and the extension line of the fixed arm 2 passes through the center of the circle where the scale disc 1 is located. The moving arm 3 integrally extends an indicating part 31 at one end, and the indicating part 31 is rotatably connected to the center of the scale disc 1 through a rotating shaft. Two positioning pieces 4 are respectively slidably connected to the fixed arm 2 and the moving arm 3. In use, the fixed arm 2 and the moving arm 3 are respectively placed on two bones, such as phalanges, of a joint to be measured, the two positioning pieces 4 are abutted on the two bones, and the positioning pieces 4 are fixed with the bones by artificial pressing or other fixing means, such as a bandage, and then flexion and extension activities are performed. In order to prevent the positioning pieces 4 from sliding off the fixed arm 2 and the moving arm 3, a limiting block 5 is fixedly arranged at the end of the fixed arm 2 and the moving arm 3 away from the scale disc 1, for limiting the farthest distance of the sliding of the limiting block.

[0055] Referring to Figure 2 As shown in the figure, the scale disc 1 is circular, and an angle scale is arranged on the surface of the scale disc 1 along the edge in the circumferential direction. The angle scale comprises a first range of 0° to 180° in the upper and lower quadrants, and a second range of 0° to 180° in the upper and lower quadrants. The first range and the second range are opposite to each other. 0° and 180° are the starting point and the ending point of the first range and the second range. The fixed arm 2 is located at the 0° scale line of the scale disc 1, and the moving arm 3 is rotatable along the first range and the second range.

[0056] Referring to Figure 2 and Figure 3 As shown in the figure, the end of the indicating part 31 of the moving arm 3 pointing to the scale on the scale disc 1 is in the shape of a sharp needle, so as to clearly point to the scale mark on the scale disc 1, avoid affecting the reading effect, or cause errors when reading. A receiving groove 311 is opened along the long axis direction of the moving arm 3 from the tip of the indicating part 31, the receiving groove 311 is perpendicular to the cross section of the moving arm 3, and the long edges of the receiving groove 311 are in the shape of open grooves. The receiving groove 311 separates the tip of the indicating part 31 into two pointers, and the scale disc 1 is connected between the two pointers through the receiving groove 311. At this time, the arrangement of the receiving groove 311 can make the moving arm 3 and the fixed arm 2 be in the same straight line.

[0057] Referring to Figures 4-6As shown, the positioning member 4 is provided with a through sliding hole 42, which is cuboid in shape, and four first guide surfaces 43. The mobile arm 3 and the fixed arm 2 are also cuboid in shape, and have four second guide surfaces 21, which match the first guide surfaces 43. The guide surfaces ensure that the fixed arm 2 and the mobile arm 3 slide stably along the long axis direction, avoiding the angle deviation caused by the self-rotation of the fixed arm 2 and the mobile arm 3 in the sliding hole 42. Meanwhile, a clamping groove 44 is provided on the positioning member 4 at the bottom of the sliding hole 42, which can be connected to other structures, such as different fixing members 6 according to the size of the measured object. The area between the sliding hole 42 and the clamping groove 44 on the positioning member 4 is a limiting portion 41, and the distance of the limiting portion 41 can be reserved according to actual needs, and enough limiting portion 41 is reserved when the positioning member 4 is prepared.

[0058] Referring to Figure 7 As shown, the fixing member 6 includes a clamping portion 61 and a plug-in portion 62, which are fixedly connected, and the clamping direction of the clamping portion 61 is opposite to the plug-in direction of the plug-in portion 62. In use, the plug-in portion 62 is connected to the clamping groove 44, connecting the fixing member 6 to the positioning member 4, and at this time the clamping portion 61 is used to clamp and fix the measured object. Figure 8 As shown, the joint protractor further includes a support member 7, the top of which is fixed with a plug-in portion 62 that matches the clamping groove 44 provided on the positioning member 4, and the bottom surface of the support member 7 is a horizontal surface. The support member 7 can be connected to the positioning member 4 of the fixed arm 2 or the positioning member 4 of the mobile arm 3, and in this embodiment it is connected to the positioning member 4 of the fixed arm 2. The support member 7 is used when measuring the metacarpal joint, and the bottom surface is placed on the dorsal side of the metacarpal bone to provide support.

[0059] In use, referring to Figure 9 As shown, when measuring the dorsiflexion of the metacarpal joint, the support member 7 is connected to the positioning block of the fixed arm 2, and the fixing member 6 is connected to the positioning block of the mobile arm 3, and the fixing member 6 is clamped to the dorsal side of the proximal phalanx and the middle phalanx by the clamping portion 61. The bottom surface of the support member 7 is placed on the metacarpal bone, and at this time the fixed support member 7 needs to be pressed manually, and the interphalangeal joint of the examinee is flexed and stretched. During the measurement process, as the dorsiflexion activity, the fixed arm 2 and the mobile arm 3 slide in the sliding hole 42 of the positioning member 4, the arm length between the two positioning members 4 decreases, and the dial 1 approaches the measured joint, but due to the existence of the limiting portion 41 in the positioning member 4, the dial 1 can still move normally, and will not affect the normal dorsiflexion activity of the joint. Figure 10As shown, when measuring the metacarpal joint dorsiflexion, with dorsiflexion activity, the fixed arm 2 and the moving arm 3 slide in the sliding hole 42 of the positioning member 4, the arm length between the two positioning members 4 increases, and the dial 1 always maintains a distance from the measuring joint and does not affect the normal activity of the joint.

[0060] Although the embodiments of the present application are described above with reference to the drawings, the present application is not limited to the specific embodiments and application fields described above, and the specific embodiments described above are merely illustrative, instructive, and not restrictive. Those skilled in the art can make many forms under the inspiration of the present specification and without departing from the scope protected by the claims of the present application, and these all belong to the protection of the present application.

Claims

1. A joint protractor, characterized in that, The joint protractor comprises a dial (1), a fixed arm (2) fixed to the dial (1), the fixed arm (2) being parallel to the line of the plane where the dial (1) is located, a moving arm (3) rotatably connected to the dial (1), the moving arm (3) and the fixed arm (2) both projecting onto the center of the circle where the dial (1) is located, and a positioning member (4) slidably connected to the same side of the moving arm (3) and the fixed arm (2), the positioning member (4) having a limiting portion (41) for limiting the distance between the moving arm (3), the fixed arm (2) and the subject. The dial (1) is marked with an angle scale for indicating the rotation angle of the moving arm (3). The angle scale has a first range and a second range marked in opposite directions, the upper and lower quadrants of the first range and the second range are both 0°-180°, the first range and the second range share the 0° line and the 180° line, and the fixed arm (2) is fixed to the 0° line or the 180° line of the dial (1). The moving arm (3) extends an indicating portion (31) rotatably connected to the dial (1) through a rotating shaft. The end of the indicating portion (31) is provided with a receiving groove (311) perpendicular to the cross section of the moving arm (3), and the dial (1) is rotatably connected in the receiving groove (311).

2. A goniometer according to claim 1, wherein, The positioning member (4) is provided with a through sliding hole (42), and the moving arm (3) and the fixed arm (2) are slidably connected to the positioning member (4) through the sliding hole (42).

3. A goniometer according to claim 2, wherein, The sliding hole (42) has a first guide surface (43) with the same guide direction as the elongation direction of the moving arm (3) and the fixed arm (2), and the moving arm (3) and the fixed arm (2) have a second guide surface (21) matched with the first guide surface (43), and the second guide surface (21) slides along the first guide surface (43).

4. A goniometer according to claim 1, wherein The moving arm (3) and the fixed arm (2) are respectively fixedly connected with a limiting block (5) away from the dial (1) to limit the sliding position of the positioning member (4).

5. A goniometer according to claim 4, wherein, The joint protractor further comprises a fixing member (6) having a clamping portion (61) fixed to the subject, and the fixing member (6) is detachably connected with the positioning member (4).

6. A goniometer according to claim 1, wherein, The side of the positioning member (4) facing the subject is provided with a clamping groove (44), and the side of the fixing member (6) opposite to the clamping portion (61) is provided with an inserting portion (62) matchable with the clamping groove (44).

7. A goniometer according to claim 6, wherein, The joint protractor further comprises a supporting member (7) detachably connected with the positioning member (4).

8. A goniometer according to claim 1, wherein, The side of the positioning member (4) facing the subject is provided with a clamping groove (44), and the side of the fixing member (6) opposite to the clamping portion (61) is provided with an inserting portion (62) matchable with the clamping groove (44).

9. A goniometer according to claim 1, wherein, ​ 10. A goniometer according to claim 9, wherein, ​ 11. A goniometer according to claim 1, wherein, ​ 12. A goniometer according to claim 9, wherein, ​ 13. A goniometer according to claim 1, wherein, The joint protractor further comprises a supporting piece (7) which is detachably connected with the positioning piece (4).

14. A goniometer according to claim 13, wherein, The positioning piece (4) is provided with a clamping groove (44) on the side facing the subject, and the supporting piece (7) is provided with an insertion part (62) which is matchable with the clamping groove (44).

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