A portable tree diameter measuring device

Abstract

The application discloses a portable tree diameter measuring device, and belongs to the technical field of tree measurement, which comprises a supporting mechanism, a positioning and clamping mechanism is arranged in the supporting mechanism, a rotary driving mechanism is arranged on the top surface of the supporting mechanism, the rotary driving mechanism comprises a supporting plate, a movable frame and a driving assembly, a measuring mechanism is arranged below the movable frame through a one-way clutch, and an angle measuring mechanism is arranged below the measuring mechanism. The fixed semicircular rack is matched with the one-way clutch, the reciprocating motion of the movable frame is converted into the one-way rotation of the measuring mechanism, the whole circular gear ring is replaced by the semicircular structure, and 360-degree full-circle scanning is realized; the radial displacement and the rotation angle are synchronously collected by the displacement sensor and the angle measuring mechanism, the complete cross-section profile data of the tree trunk are acquired, and the measurement accuracy of the irregular tree trunk is improved; the openable and closable supporting ring and the handle are adopted, the structure is compact, the device is convenient to carry, and the device is suitable for field operation.

Description

Technical Field

[0001] This invention relates to the field of tree measurement technology, and more particularly to a portable tree diameter at breast height (DBH) measuring device. Background Technology

[0002] Tree diameter at breast height (DBH, or diameter of the trunk at 1.3 meters above the ground) is one of the most basic and important measurement indicators in forestry resource surveys, forest ecology research, and timber production management. Accurate and efficient measurement of DBH is of great value for forest resource assessment, carbon sequestration, and tree growth monitoring.

[0003] Currently, traditional tools for measuring tree diameter at breast height (DBH) mainly include: 1. Circumference measuring tape: A flexible measuring tape is wrapped around the tree trunk to measure the circumference and then convert it to diameter. Its advantages are simple structure and low cost, but it requires both hands to wrap around the trunk during operation, which is inconvenient in forest areas with dense shrubs or irregular trunks; moreover, it can only measure the circumference and cannot obtain information about the shape of the trunk cross section. For elliptical or irregularly shaped trunks, the error of a single measurement is relatively large.

[0004] 2. Calipers: The diameter is read directly by clamping the tree trunk with two feet. Its advantage is that it is relatively easy to operate, but the measuring range is limited by the length of the calipers, and multiple measurements are required for large-diameter trees; at the same time, the calipers are large and inconvenient to carry, and they can only measure the diameter in one direction, and cannot reflect the ellipticity of the cross section.

[0005] The following common problems still exist in existing technologies: The contradiction between portability and measurement range: large-size measuring devices can measure large-diameter trees, but they are inconvenient to carry; portable devices often have limited range.

[0006] Measurement accuracy issues with irregular tree trunks: Most devices assume the tree trunk is circular, and for elliptical or irregularly shaped tree trunks, the error in a single or unidirectional measurement is relatively large.

[0007] Operational complexity issues: Some devices require multiple people to cooperate or complex operations, making them inconvenient to use in the field.

[0008] Therefore, developing a tree diameter at breast height (DBH) measuring device that is simple in structure, easy to carry, capable of high-precision measurement of irregular tree trunk cross sections, and convenient to operate has important practical significance and application value. Summary of the Invention

[0009] The purpose of this invention is to provide a portable tree diameter at breast height (DBH) measuring device to solve the problems described in the background art.

[0010] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: This invention discloses a portable tree diameter at breast height (DBH) measuring device, comprising a support mechanism with several positioning and clamping mechanisms within it. A rotary drive mechanism is located on the top surface of the support mechanism, comprising a semi-circular support plate. A movable frame and a drive assembly for moving the movable frame are mounted on the support plate. A measuring mechanism is located below the movable frame via a one-way clutch. The one-way clutch transmits power to the measuring mechanism when the drive assembly moves in a first direction and cuts off power transmission when the drive assembly moves in the opposite direction. The measuring mechanism includes a probe that can extend and retract radially along the tree trunk and a displacement sensor for measuring the radial displacement of the probe. An angle measuring mechanism is located below the measuring mechanism for detecting the rotation angle of the measuring mechanism.

[0011] Furthermore, the support mechanism includes two openable support rings, which are connected together by a connecting post, and the connecting post is provided with a handle.

[0012] Furthermore, the openable support ring includes a fixed half-ring and an openable half-ring, with one end of the fixed half-ring and the openable half-ring hinged together and the other end detachably locked together, forming a ring structure around the tree trunk when closed.

[0013] Furthermore, the other end of the fixed half-ring and the opening / closing half-ring is provided with an opening / closing drive component.

[0014] Furthermore, the free end of the fixed semi-ring is provided with a locking block, and the free end of the opening and closing semi-ring is provided with a locking groove that matches the locking block.

[0015] Furthermore, the positioning and clamping mechanism includes a support rod disposed between the two openable support rings. A clamping block is disposed on the upper part of the support rod via a connecting rod. A clamping drive is disposed on the lower part of the support rod. A movable seat is disposed on the top of the clamping drive. A first sliding groove matching the movable seat is disposed on the support rod. The movable seat is connected to the clamping block via an elastic telescopic component.

[0016] Furthermore, the elastic telescopic assembly includes a first rod disposed on the movable seat and a second rod disposed on the clamping block. A third rod is disposed on the top of the first rod. A second sliding groove matching the top of the third rod is disposed on the second rod. A first spring is disposed on the third rod.

[0017] Furthermore, the driving assembly includes a semi-circular rack disposed on the outer wall of the support plate, a movable driving member disposed on the top surface of the movable frame, a first gear disposed on the output shaft of the movable driving member, a second gear meshing with the side of the first gear, a first rotating shaft disposed at the center of the second gear, a third gear disposed on the first rotating shaft meshing with the rack, an inner limiting roller disposed on the movable frame that contacts the inner side wall of the support plate, and an outer limiting roller disposed on the first rotating shaft that contacts the outer side wall of the support plate.

[0018] Furthermore, the measuring mechanism includes a gear ring composed of two parts joined together. The gear ring is mounted on the upper openable support ring. A fourth gear is meshed with one side of the gear ring, and a second rotating shaft is located at the center of the fourth gear. The one-way clutch is connected between the first rotating shaft and the second rotating shaft. A connecting post is provided on the gear ring, and a fixed tube is provided at the other end of the connecting post. A movable plate is provided inside the fixed tube. A second spring is provided on one side of the movable plate, and a probe rod is provided on the other side of the movable plate. A probe is provided at the end of the probe rod away from the movable plate, and a displacement sensor is provided at the end of the probe rod near the movable plate. A limit sleeve is provided on the fixed tube, and the probe rod extends outward after passing through the limit sleeve.

[0019] Furthermore, the angle measuring mechanism includes an annular grating ruler and a grating reading head. The annular grating ruler is circumferentially arranged on the upper openable support ring, and the grating reading head is arranged below the fixed tube via a mounting rod. The grating reading head is arranged opposite to the annular grating ruler and is used to read the rotation angle of the fixed tube relative to the openable support ring.

[0020] Compared with the prior art, the beneficial technical effects of the present invention are as follows: 1. An innovative measurement method of semi-circular drive and full-circle scanning has been realized. This invention employs a fixed semi-circular rack in conjunction with a movable frame that can move along it. A one-way clutch converts the reciprocating motion of the movable frame into the one-way rotational motion of the measuring mechanism. Each time the movable frame completes one forward stroke, the measuring mechanism rotates 180°, and two reciprocations are sufficient to achieve a 360° full-circumference scan.

[0021] 2. Continuous tree trunk cross-sectional profile data were obtained, significantly improving measurement accuracy. This invention measures the radial displacement d(θ) of the probe in real time using a displacement sensor and simultaneously measures the rotation angle θ using an angle measuring mechanism, continuously acquiring a series of (θ,d) data points during the scanning process. These data points can reconstruct the complete cross-sectional profile of the tree trunk at the measurement height, enabling the calculation of not only the average diameter at breast height (DBH) but also the acquisition of the maximum and minimum diameters, and analysis of the trunk's ellipticity and irregularity. Compared to existing single-point or unidirectional measurement methods, this invention provides richer data and higher accuracy, making it particularly suitable for measuring irregular tree trunks.

[0022] 3. Openable and foldable design, good portability This invention employs two openable support rings arranged vertically and connected by a connecting column, with a handle included. In use, the opening / closing drive mechanism opens the half-rings, facilitating the insertion of the device into the tree trunk. After use, it can be closed and folded for easy carrying. The overall structure is compact and suitable for field operations. Attached Figure Description

[0023] The present invention will be further described below with reference to the accompanying drawings.

[0024] Figure 1 This is a front view of the portable tree diameter at breast height (DBH) measuring device of the present invention. Figure 2 This is a side view of the portable tree diameter at breast height (DBH) measuring device of the present invention. Figure 3 This is a top view of the portable tree diameter at breast height measuring device of the present invention; Figure 4 This is a schematic diagram of the support mechanism of the present invention; Figure 5 for Figure 4 Enlarged view of point A in the middle; Figure 6 This is a schematic diagram of the positioning and clamping mechanism of the present invention; Figure 7 for Figure 6 Enlarged view of point B in the middle; Figure 8 This is a schematic diagram of the rotary drive mechanism of the present invention; Figure 9 This is a schematic diagram of the rotary drive mechanism of the present invention from another angle; Figure 10 This is a front view of the measuring mechanism of the present invention; Figure 11 This is a cross-sectional view of the measuring mechanism of the present invention.

[0025] Explanation of reference numerals in the attached drawings: 1. Openable support ring; 11. Fixed half-ring; 111. Locking block; 12. Openable half-ring; 121. Locking groove; 13. Opening / closing drive component; 2. Connecting column; 3. Handle; 4. Positioning and clamping mechanism; 41. Support rod; 411. First slide groove; 42. Connecting rod; 43. Clamping block; 44. Clamping drive component; 45. Moving seat; 46. Elastic telescopic assembly; 461. First rod; 462. Second rod; 4621. Second slide groove; 463. Third rod; 464. First spring; 5. Rotation drive mechanism; 51 52. Support plate; 53. Rack; 54. Movable frame; 55. Movable drive component; 56. First gear; 57. First rotating shaft; 58. Second gear; 59. Third gear; 50. Outer limiting roller; 510. Inner limiting roller; 61. Measuring mechanism; 62. Connecting column; 63. Fixed tube; 64. Moving plate; 65. Second spring; 66. Probe rod; 67. Probe; 68. Limiting sleeve; 69. Second rotating shaft; 60. Displacement sensor; 610. Fourth gear; 611. Gear ring; 7. One-way clutch; 8. Angle measuring mechanism; 9. Tree trunk. Detailed Implementation

[0026] like Figure 1-11 As shown, a portable tree diameter at breast height (DBH) measuring device includes a support mechanism with three positioning clamping mechanisms 4 installed within it. These clamping mechanisms 4 clamp the tree trunk 9, thus fixing the device to the trunk 9. A rotary drive mechanism 5 is mounted on the top surface of the support mechanism. The rotary drive mechanism 5 includes a semi-circular support plate 51, on which a movable frame 53 and a drive assembly for moving the movable frame 53 are mounted. The movable frame 53 can move along the semi-circular support plate 51. A measuring mechanism 6 is connected below the movable frame 53 via a one-way clutch 7. The one-way clutch 7 transmits power to the measuring mechanism 6 when the drive assembly moves in a first direction and cuts off power transmission when the drive assembly moves in the opposite direction. The measuring mechanism 6 includes a probe 66 that can extend and retract radially along the tree trunk 9 and a displacement sensor 69 for measuring the radial displacement of the probe 66. An angle measuring mechanism 8 is mounted below the measuring mechanism 6 for detecting the rotation angle of the measuring mechanism 6.

[0027] like Figure 4As shown, the support mechanism includes two openable support rings 1, which are concentrically arranged vertically. The two openable support rings 1 are connected together by a connecting post 2, on which a handle 3 is attached for easy movement of the device. Specifically, each openable support ring 1 includes a fixed half-ring 11 and an openable half-ring 12. One end of the fixed half-ring 11 and the openable half-ring 12 is hinged, and the other end is detachably locked, forming a ring structure around the tree trunk 9 when closed. The other end of the fixed half-ring 11 and the openable half-ring 12 is provided with an opening / closing drive component 13. The opening / closing drive component 13 can be an existing component such as an electric push rod, hydraulic cylinder, or pneumatic cylinder. The opening / closing drive component 13 drives the openable half-ring 12 to open, allowing the device to be installed on the tree trunk 9. Figure 5 As shown, the free end of the fixed semi-ring 11 is connected to a locking block 111, and the free end of the opening and closing semi-ring 12 is provided with a locking groove 121 that matches the locking block 111.

[0028] In use, the opening and closing drive 13 drives the opening and closing half ring 12 to open, placing the device outside the trunk 9. Then, the opening and closing drive 13 drives the opening and closing half ring 12 to close, forming a ring structure around the trunk 9 between the fixed half ring 11 and the opening and closing half ring 12.

[0029] like Figure 4 , 6 As shown in Figure 7, the positioning and clamping mechanism 4 includes a support rod 41 installed between the two openable support rings 1. A clamping block 43 is provided on the upper part of the support rod 41 via a connecting rod 42. One end of the connecting rod 42 is hinged to the support rod 41, and the other end is hinged to the clamping block 43. There are four connecting rods 42, arranged symmetrically in pairs. A clamping drive component 44 is installed on the lower part of the support rod 41. The clamping drive component 44 can be an existing component such as an electric push rod, hydraulic cylinder, or pneumatic cylinder. A movable seat 45 is installed on the top of the clamping drive component 44. A first sliding groove 411 matching the movable seat 45 is provided on the support rod 41. A crossbar at the top of the movable seat 45 passes through the first sliding groove 411 and moves vertically within the first sliding groove 411. The movable seat 45 is connected to the clamping block 43 via an elastic telescopic component 46. The surface of the clamping block 43 is provided with anti-slip textures. Specifically, as shown... Figure 7 As shown, the elastic telescopic assembly 46 includes a first rod 461 hinged to the movable seat 45 and a second rod 462 hinged to the clamping block 43. A third rod 463 is connected to the top of the first rod 461. A second slide groove 4621 matching the top of the third rod 463 is provided on the second rod 462. A crossbar at the top of the third rod 463 passes through the second slide groove 4621 and moves within the second slide groove 4621. A first spring 464 is sleeved on the third rod 463.

[0030] In use, the working rod of the clamping drive 44 drives the moving seat 45 to move upward. The moving seat 45 pushes the clamping blocks 43 towards the trunk 9, and the three clamping blocks 43 clamp the trunk 9, thereby fixing the device to the trunk 9. The positioning clamping mechanism 4 of the present invention uses an elastic telescopic component 46 to connect the clamping blocks 43. When the clamping blocks 43 contact the trunk 9, the first spring 464 begins to compress, keeping the clamping force within a certain range, ensuring that the device is firmly fixed and avoiding damage to the bark due to excessive clamping force. The three clamping blocks 43 apply force evenly from three directions, which can adapt to trunks of different diameters and shapes, and the installation is stable and reliable.

[0031] like Figure 8-9 As shown, the drive assembly includes a semi-circular rack 52 mounted on the outer wall of the support plate 51. A movable drive component 54, which can be a motor, is mounted on the top surface of the movable frame 53. A first gear 55 is mounted on the output shaft of the movable drive component 54. A second gear 57 is meshed with the side of the first gear 55. A first rotating shaft 56 is mounted at the center of the second gear 57. A third gear 58, which meshes with the rack 52, is mounted on the first rotating shaft 56. An inner limiting roller 510, which contacts the inner wall of the support plate 51, is mounted on the movable frame 53. An outer limiting roller 59, which contacts the outer wall of the support plate 51, is mounted on the first rotating shaft 56. In this invention, the outer limiting roller 59 and the inner limiting roller 510 are provided on the movable frame 53, which roll in contact with the outer and inner walls of the support plate 51, respectively, forming a double-sided limiting guide to ensure that the movable frame 53 runs smoothly along the semi-circular rack 52 without shaking or uneven load. Meanwhile, the meshing transmission between the third gear 58 and the semi-circular rack 52, compared to friction drive, eliminates the risk of slippage, resulting in high transmission accuracy and long service life. Limit switches are located at both ends of the semi-circular rack 52. When the movable frame 53 moves to the endpoint of the semi-circular rack 52, the limit switches are triggered, controlling the movable drive component 54 to reverse. The main actions of this invention (support ring opening and closing, clamping and positioning, scanning drive, and data acquisition) can all be automatically or assisted by the control system. The operator only needs to place the device next to the tree trunk and turn on the switch. The limit switches at both ends of the semi-circular rack 52 automatically control the reversal of the movable frame 53, eliminating the need for manual intervention and reducing operational difficulty and reliance on operator experience.

[0032] In use, the movable drive component 54 drives the first gear 55 to rotate, the first gear 55 rotates to drive the second gear 57 to rotate, the second gear 57 rotates to drive the first rotating shaft 56 to rotate, the first rotating shaft 56 rotates to drive the third gear 58 to rotate, and the third gear 58 rotates to drive the movable frame 53 to move along the support plate 51. When the movable frame 53 moves in the first direction, the one-way clutch 7 transmits power to the measuring mechanism 6, and cuts off the power transmission when the movable frame 53 moves in the opposite direction.

[0033] like Figure 10-11 As shown, the measuring mechanism 6 includes a circular gear ring 611 formed by splicing two semi-circular gear rings. The gear ring 611 is rotatably mounted on the openable support ring (1) located above via bearings. A fourth gear 610 is meshed with one side of the gear ring 611. A second rotating shaft 68 is mounted at the center of the fourth gear 610. The one-way clutch 7 is connected between the first rotating shaft 56 and the second rotating shaft 68. A connecting post 61 is mounted on the gear ring 611. A fixed tube 62 is connected to the other end of the connecting post 61. A movable plate 63 is slidably mounted inside the fixed tube 62. Slider blocks are connected to the upper and lower sides of the movable plate 63. The inner wall of tube 62 is provided with a groove that matches the slider; a second spring 64 is connected to one side of the moving plate 63, and a probe rod 65 is connected to the other side of the moving plate 63. A probe 66 is installed at the end of the probe rod 65 away from the moving plate 63. The second spring 64 keeps the probe 66 in contact with the surface of the trunk 9. A displacement sensor 69 is installed at the end of the probe rod 65 near the moving plate 63. The displacement sensor 69 is an LVDT or a precision potentiometer, and its measuring rod is connected to the other end of the probe rod; a limiting sleeve 67 is provided on the fixed tube 62, and the probe rod 65 extends outward after passing through the limiting sleeve 67.

[0034] The angle measuring mechanism 8 includes an annular grating ruler and a grating reading head. The annular grating ruler is circumferentially arranged on the upper openable support ring 1. The grating reading head is arranged below the fixed tube 62 via a mounting rod. The grating reading head is arranged opposite to the annular grating ruler and is used to read the rotation angle of the fixed tube 62 relative to the openable support ring 1.

[0035] The working process of this invention is as follows: I. Equipment Installation and Positioning Stage Step 1: Open the support ring The operator holds the handle 3 and moves the device to the side of the tree trunk 9 to be measured. The opening and closing drive 13 is activated, which pushes the opening and closing half ring 12, causing the opening and closing half ring 12 to rotate outward around the hinge point, opening the openable support ring 1. At this time, the fixed half ring 11 and the opening and closing half ring 12 separate, forming an opening that allows the tree trunk 9 to enter.

[0036] Step 2: Close the support ring Move the device to the outside of the tree trunk 9, positioning the tree trunk 9 in the central area of ​​the two openable support rings 1. Activate the opening / closing drive 13 in the reverse direction, pulling the opening / closing half-ring 12 inward to close it. When the slot 121 at the free end of the opening / closing half-ring 12 aligns and engages with the locking block 111 at the free end of the fixed half-ring 11, the two openable support rings 1 form a closed ring structure surrounding the tree trunk 9. At this point, the two openable support rings 1 are concentrically arranged vertically and fixedly connected by the connecting column 2, providing a stable reference frame for subsequent measurements.

[0037] Step 3: Clamp and position When the clamping drive 44 is activated, the working rod of the clamping drive 44 pushes the moving seat 45 to move upward along the first slide groove 411 on the support rod 41; when the moving seat 45 moves upward, it pushes the clamping block 43 to move closer to the tree trunk 9 through the elastic telescopic component 46.

[0038] The working principle of the elastic telescopic component 46 is as follows: the moving seat 45 moves upward, driving the first rod 461 to move upward. The first rod 461 drives the second rod 462 through the third rod 463, thereby pushing the clamping block 43 closer to the tree trunk 9. When the clamping block 43 contacts the surface of the tree trunk 9, if the clamping force continues to be applied, the first spring 464 begins to compress, so that the clamping block 43 and the tree trunk 9 maintain an appropriate elastic contact force, which ensures reliable clamping and avoids damage to the bark.

[0039] The three positioning and clamping mechanisms 4 operate synchronously, with their clamping blocks 43 clamping the tree trunk 9 evenly from three directions, firmly fixing the entire device to the tree trunk 9. The anti-slip texture on the surface of the clamping blocks 43 increases friction and prevents the device from sliding or rotating during measurement.

[0040] At this point, the device installation is complete, and the measurement benchmark has been established.

[0041] II. Measurement Preparation Stage Step 4: Initialize the measuring mechanism The control system issues a command to confirm that all components are in their initial state: The movable frame 53 is located at the starting end (such as the extreme position of one end) of the semi-circular support plate 51. The probe 66 of the measuring mechanism 6 is in the extended state under the action of the second spring 64; Align the grating reading head with the annular grating ruler and record the initial angle value; Step 5: Check the condition of the one-way clutch Manually or automatically check the working direction of the one-way clutch 7 to ensure that its installation direction is correct: when the movable frame 53 moves in the first direction (such as clockwise), the one-way clutch 7 is in the locked state; when the movable frame 53 moves in the opposite direction, the one-way clutch 7 is in the overrunning state.

[0042] III. Scanning Measurement Stage Step 6: Forward drive (effective scan range) The movable drive component 54 is activated, which drives the first gear 55 to rotate. The first gear 55 meshes with the second gear 57, driving the second gear 57 to rotate. The second gear 57 drives the first rotating shaft 56 to rotate. The first rotating shaft 56 drives the third gear 58 to rotate. Since the third gear 58 meshes with the semi-circular rack 52 fixed on the support plate 51, the rotation of the third gear 58 generates a reaction force, which pushes the entire movable frame 53 to move along the semi-circular rack 52.

[0043] During the movement of movable frame 53: The outer limiting roller 59 rolls in contact with the outer wall of the support plate 51, and the inner limiting roller 510 rolls in contact with the inner wall of the support plate 51. Together, they ensure the smooth operation of the movable frame 53 and prevent shaking or deviation.

[0044] At this time, the movable frame 53 moves in the first direction (such as clockwise), and the one-way clutch 7 is in the locked state: The inner ring of the one-way clutch 7 rotates with the first rotating shaft 56; The outer ring of the one-way clutch 7 drives the second rotating shaft 68 to rotate through a locking action; The second rotating shaft 68 drives the fourth gear 610 to rotate; The fourth gear 610 drives the gear ring 611 to rotate; The gear ring 611 drives the connecting post 61 and the fixing tube 62 to rotate around the center of the tree trunk 9; During rotation, the probe 66 of the measuring mechanism 6 remains in close contact with the surface of the trunk 9 under the action of the second spring 64. As the diameter of the trunk 9 changes, the probe 66 drives the probe rod 65 to move radially within the fixed tube 62. The displacement sensor 69 measures the amount of movement of the probe rod 65 in real time, that is, the change in radial distance d(θ) of the trunk surface relative to the reference circle of the fixed tube 62.

[0045] Simultaneously, the angle measuring mechanism 8 operates synchronously: The grating reading head below the fixed tube 62 rotates together with the measuring mechanism 6; The grating reading head reads the annular grating ruler fixed on the openable support ring 1; Real-time output of the current rotation angle θ of the measuring mechanism 6; The control system synchronously acquires the radial displacement data d output by the displacement sensor 69 and the angle data θ output by the grating reading head, forming a series of data point pairs (θ,d).

[0046] Step 7: Reaching the End Point and Changing Direction When the movable frame 53 moves to the end point along the semi-circular rack 52, the limit switches installed at both ends of the semi-circular rack 52 are triggered. The limit switches send a signal to the control system, and the control system immediately instructs the movable drive component 54 to stop and prepare for reverse operation.

[0047] Step 8: Reverse drive (return stroke) The control system commands the movable drive component 54 to rotate in the reverse direction. The movable drive component 54 drives the first gear 55 to rotate in the reverse direction, which in turn causes the third gear 58 to rotate in the reverse direction through gear transmission, driving the movable frame 53 to move in the reverse direction along the semi-circular rack 52 (returning to the starting end).

[0048] During this process, the one-way clutch 7 is in an overrunning state: The inner ring of the one-way clutch 7 rotates in the opposite direction to the first rotating shaft 56; The outer ring of the one-way clutch 7 is not driven and remains stationary; Therefore, the measuring mechanism 6 does not return with the movable frame 53, but remains in its current position. Due to the overrunning action of the one-way clutch 7, the measuring mechanism 6 remains stationary during the reverse stroke and does not retract, thus ensuring the continuity of the scan.

[0049] Step 9: Reciprocating Cycle and Cumulative Rotation Repeat steps 6-8: Each forward stroke, the movable frame 53 moves 180° along the semi-circular rack 52, and the measuring mechanism 6 rotates 180° accordingly. Each time the reverse stroke occurs, the movable frame 53 returns, while the measuring mechanism 6 remains stationary; After two reciprocating strokes (i.e., two forward strokes), the measuring mechanism 6 rotates a cumulative 360°, completing the scan of the entire circumference of the tree trunk 9. During the scanning process, the control system continuously collects (θ,d) data points to obtain the complete cross-sectional profile data of the tree trunk 9 at the measurement height.

[0050] IV. Data Calculation and Output Stage Step 10: Data Processing After the scan is completed, the data processing unit in the control system performs calculations based on the collected data: Coordinate transformation: Calculate the polar coordinate position of the point on the tree trunk surface according to the formula R(θ)=R0-d(θ), where R0 is the reference radius (a known constant) from the rotation center of the fixed tube 62 to the initial position of the probe 66.

[0051] Contour reconstruction: Draw the radius R(θ) corresponding to each angle θ in the polar coordinate system to obtain the actual contour of the tree trunk cross section.

[0052] Calculation of chest diameter: Calculate the average value of all R(θ) to obtain the average radius, and then calculate the average diameter at breast height; Find the maximum radius R_max and the minimum radius R_min, and calculate the maximum diameter and the minimum diameter; If the cross-section of the tree trunk is approximately elliptical, ellipse fitting can be performed to calculate the major and minor axes; Results output: The calculated diameter at breast height (DBH), cross-sectional profile data, and measurement time are stored locally or uploaded to the terminal device via a wireless module.

[0053] V. Disassembly and Storage Stage Step 11: Release the clamping mechanism After the measurement is completed, the clamping drive 44 is activated in reverse, causing the movable seat 45 to move downwards. The movable seat 45, through the elastic telescopic component 46, moves the clamping block 43 away from the tree trunk 9, releasing the clamp on the tree trunk. The first spring 464 returns to its original position, preparing for the next measurement.

[0054] Step 12: Open the support ring The opening and closing drive component 13 is activated in the reverse direction, pushing the opening and closing half ring 12 to rotate outward and open, so that the openable and closable support ring 1 is separated from the trunk 9.

[0055] Step 13: Remove the device The operator uses handle 3 to remove the device from the tree trunk 9. The two openable support rings 1 can be folded and stored for easy transport to the next measurement point.

[0056] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A portable device for measuring tree diameter at breast height (DBH), characterized in that: The system includes a support mechanism, which contains several positioning and clamping mechanisms (4). A rotary drive mechanism (5) is provided on the top surface of the support mechanism. The rotary drive mechanism (5) includes a semi-circular support plate (51). A movable frame (53) and a drive assembly for moving the movable frame (53) are provided on the support plate (51). A measuring mechanism (6) is provided below the movable frame (53) via a one-way clutch (7). The one-way clutch (7) is used to transmit power to the measuring mechanism (6) when the drive assembly moves in a first direction and to cut off the power transmission when the drive assembly moves in the opposite direction. The measuring mechanism (6) includes a probe (66) that can extend and retract radially along the trunk (9) and a displacement sensor (69) for measuring the radial displacement of the probe (66). An angle measuring mechanism (8) is provided below the measuring mechanism (6). The angle measuring mechanism (8) is used to detect the rotation angle of the measuring mechanism (6).

2. The portable tree diameter at breast height (DBH) measuring device according to claim 1, characterized in that: The support mechanism includes two openable support rings (1), which are connected together by a connecting post (2), and a handle (3) is provided on the connecting post (2).

3. The portable tree diameter at breast height (DBH) measuring device according to claim 2, characterized in that: The openable support ring (1) includes a fixed half ring (11) and an openable half ring (12). One end of the fixed half ring (11) and the openable half ring (12) are hinged together, and the other end is detachably locked together. When closed, they form a ring structure around the trunk (9).

4. The portable tree diameter at breast height (DBH) measuring device according to claim 3, characterized in that: The other end of the fixed half-ring (11) and the opening and closing half-ring (12) is provided with an opening and closing drive member (13).

5. The portable tree diameter at breast height (DBH) measuring device according to claim 3, characterized in that: The free end of the fixed half ring (11) is provided with a locking block (111), and the free end of the opening and closing half ring (12) is provided with a slot (121) that matches the locking block (111).

6. The portable tree diameter at breast height (DBH) measuring device according to claim 2, characterized in that: The positioning and clamping mechanism (4) includes a support rod (41) disposed between the two openable support rings (1). A clamping block (43) is disposed on the upper part of the support rod (41) via a connecting rod (42). A clamping drive (44) is disposed on the lower part of the support rod (41). A movable seat (45) is disposed on the top of the clamping drive (44). A first sliding groove (411) matching the movable seat (45) is disposed on the support rod (41). The movable seat (45) is connected to the clamping block (43) via an elastic telescopic component (46).

7. The portable tree diameter at breast height (DBH) measuring device according to claim 6, characterized in that: The elastic telescopic assembly (46) includes a first rod (461) disposed on the movable seat (45) and a second rod (462) disposed on the clamping block (43). A third rod (463) is disposed on the top of the first rod (461). A second slide groove (4621) matching the top of the third rod (463) is disposed on the second rod (462). A first spring (464) is disposed on the third rod (463).

8. The portable tree diameter at breast height (DBH) measuring device according to claim 2, characterized in that: The drive assembly includes a semi-circular rack (52) disposed on the outer wall of the support plate (51), a movable drive member (54) disposed on the top surface of the movable frame (53), a first gear (55) disposed on the output shaft of the movable drive member (54), a second gear (57) meshing with the side of the first gear (55), a first rotating shaft (56) disposed at the center of the second gear (57), a third gear (58) meshing with the rack (52) disposed on the first rotating shaft (56), an inner limiting roller (510) contacting the inner side wall of the support plate (51) disposed on the movable frame (53), and an outer limiting roller (59) contacting the outer side wall of the support plate (51) disposed on the first rotating shaft (56).

9. The portable tree diameter at breast height (DBH) measuring device according to claim 8, characterized in that: The measuring mechanism (6) includes a gear ring (611) composed of two parts joined together. The gear ring (611) is mounted on the upper openable support ring (1). A fourth gear (610) is meshed with one side of the gear ring (611). A second rotating shaft (68) is located at the center of the fourth gear (610). The one-way clutch (7) is connected between the first rotating shaft (56) and the second rotating shaft (68). A connecting post (61) is provided on the gear ring (611), and a fixing tube is provided at the other end of the connecting post (61). 62), a movable plate (63) is provided inside the fixed tube (62), a second spring (64) is provided on one side of the movable plate (63), a probe rod (65) is provided on the other side of the movable plate (63), a probe (66) is provided at the end of the probe rod (65) away from the movable plate (63), a displacement sensor (69) is provided at the end of the probe rod (65) close to the movable plate (63), a limiting sleeve (67) is provided on the fixed tube (62), and the probe rod (65) extends outward after passing through the limiting sleeve (67).

10. The portable tree diameter at breast height (DBH) measuring device according to claim 9, characterized in that: The angle measuring mechanism (8) includes an annular grating ruler and a grating reading head. The annular grating ruler is circumferentially arranged on the upper openable support ring (1). The grating reading head is arranged below the fixed tube (62) by a mounting rod. The grating reading head is arranged opposite to the annular grating ruler and is used to read the rotation angle of the fixed tube (62) relative to the openable support ring (1).

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