Compasses capable of displaying pitch

Abstract

The compasses capable of displaying the foot pitch comprise a compasses head, a positioning foot and a rotating foot, the positioning foot and the rotating foot are connected to the compasses head in a relatively rotating mode, gear structures meshed with each other are arranged on the tops of the positioning foot and the rotating foot, a rotatable rotating column is arranged on the compasses head, and the rotating column is in driving connection with at least one of the positioning foot and the rotating foot. When the positioning foot and the rotating foot rotate relatively, the rotating column can be driven to rotate synchronously. The compass head is further provided with a reading module, and the reading module comprises an indicating component and a scale component which are in linkage with the rotating column. The indicating part synchronously rotates along with the rotating column, and the real-time foot pitch size between the positioning foot and the rotating foot is directly displayed through the change of the relative position of the indicating part and the scale part. Compared with the prior art, the compass has the advantages that the tedious mode that the radius of a traditional compass is manually adjusted through a ruler is abandoned, the defects that an electronic compass is high in cost, prone to electromagnetic interference and the like are overcome, accurate foot pitch measurement can be achieved only through a simple mechanical structure, and the compass has the advantages of being low in cost, free of electromagnetic interference, high in measurement accuracy and durable.

Description

Technical Field

[0001] This utility model relates to the field of compass technology, and in particular to a compass that can display the distance between the feet. Background Technology

[0002] In the field of drawing tools, the compass is the core tool for drawing circles, and its performance directly affects drawing efficiency and accuracy. However, traditional compasses lack built-in measuring functions, requiring manual adjustment of the radius using a ruler. This process is cumbersome, and repeated adjustments can easily introduce errors. Especially in precision drawing, even minor errors can render the entire drawing unusable, thus affecting both efficiency and quality.

[0003] While some electronic compasses measure radius using sensors and can directly display the value, they have many drawbacks. Their high cost keeps prices high, hindering widespread adoption; in environments with strong electromagnetic interference (such as factory workshops), measurement results are prone to deviation or even complete inaccuracy; moreover, electronic components have a limited lifespan, and measurement accuracy gradually decreases after prolonged use, failing to meet the requirements for continuous and stable operation.

[0004] Later, some improved compasses emerged, attempting to combine electronic measurement with mechanical structures. For example, the Chinese invention patent application No. 202211283304.4 (publication number CN115416418A) discloses "A Compass," which includes a knob, a horizontal axis fixedly connected to the bottom of the knob, a left leg and a right leg hinged to the horizontal axis, a circular protractor fixed to one end of the horizontal axis, a sensing module disposed on the inner side of the bottom of the left leg, a receiving module disposed on the inner side of the bottom of the right leg, a data processing module disposed on the inner side of the circular protractor and connected to the sensing module and the receiving module respectively, and a display screen fixedly disposed on the outer side of the circular protractor and connected to the data processing module. Through the cooperation of the sensing module and the receiving module, this compass can measure the angle and straight-line distance between the two legs, thereby intuitively determining the radius of the circle or arc to be drawn.

[0005] However, this type of compass also has drawbacks: because it still uses electronic sensing elements, it cannot escape the inherent problems of electronic compasses. On the one hand, the use of electronic components such as the sensing module, receiving module, data processing module, and display screen, and the need for a power supply, significantly increases the production cost of the compass; on the other hand, the stability of the electronic components depends on a stable electromagnetic environment. In places with strong electromagnetic interference, the normal operation of the electronic components will be affected, data transmission between the sensing module and the receiving module may be interrupted or erroneous, and the data processing module may also have calculation deviations, resulting in inaccurate radius values ​​displayed on the screen and affecting the accuracy of the drawing.

[0006] Therefore, how to provide a compass that is low in cost, unaffected by electromagnetic interference, highly accurate and durable, capable of accurately measuring and drawing circles with a simple mechanical structure, stable in various complex environments, and capable of rapid radius adjustment is a problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0007] The technical problem to be solved by this utility model is to provide a compass with a novel structure that can accurately measure and draw circles using only a simple mechanical structure, can be used stably in a variety of complex environments, and can also quickly adjust the radius and display the distance between the feet, in order to address the above-mentioned existing technology.

[0008] The technical solution adopted by this utility model to solve the above-mentioned technical problems is as follows: the compass that can display the distance between the feet includes a compass head, a positioning foot and a rotating foot. The positioning foot and the rotating foot are rotatably connected to the compass head, and the top of the positioning foot and the top of the rotating foot are respectively provided with mutually meshing gear structures.

[0009] The compass head is provided with a rotatable rotating column, which is driven to at least one of the positioning foot or the rotating foot. The relative rotation of the positioning foot and the rotating foot can drive the rotating column to rotate synchronously.

[0010] The compass head is equipped with a reading module, which includes an indicator component linked to the rotating column and a scale component on the compass head. The indicator component rotates synchronously with the rotating column and directly displays the real-time distance between the positioning foot and the rotating foot by changing its relative position with the scale component.

[0011] To make readings clearer and more intuitive, and to facilitate users in reading compass leg distance dimensions, preferably, the indicating component includes an indicating disk, and the scale component includes a scale disk. The indicating disk and the scale disk are coaxially arranged, and the indicating disk can rotate relative to the scale disk under the drive of the rotating column. The upper surface of the scale disk has circumferentially distributed scale values, and the indicating disk has visible marks that point to the scale values. This coaxial arrangement and the design of the visible marks allow users to quickly and accurately obtain leg distance information, improving drawing efficiency.

[0012] To enhance the interest and uniqueness of the reading structure, and to ensure that the visual marks can be accurately formed and point to the scale value, preferably, the indicator dial and the scale dial are coaxially stacked, and the indicator dial is attached to the bottom of the scale dial.

[0013] Both the indicator dial and the scale dial are elastically deformable thin sheet structures; the surface of the indicator dial is provided with a first through slit extending radially and a second through slit connected to the first through slit and extending circumferentially, the first through slit and the second through slit together divide the indicator dial into an annular elastically deformable region.

[0014] The corresponding position of the scale is provided with a third through slit that extends radially and allows the annular area to pass through.

[0015] When the indicator dial rotates relative to the scale dial, the elastically deformable area can extend upwards through the three through-slits and be exposed on the upper surface of the scale dial, forming a visible mark corresponding to the scale value. This method of forming a visible mark through elastic deformation, through a clever mechanical movement structure, enhances the product's novelty while ensuring functionality.

[0016] To further enhance the readability and reduce reading errors, preferably, the surface color of the indicator dial is different from the surface color of the scale dial. The visible markings formed on the indicator dial, through the color difference, can create a visual contrast with the scale values ​​of the scale dial, thereby enhancing the readability. The color difference design makes the readings more eye-catching, reduces the possibility of misreading, and improves the user experience.

[0017] To make the compass's internal structure more compact and rational, and to facilitate the installation and maintenance of each component, preferably, the compass head includes a base and a cover that fit together. The base and the cover together form a receiving cavity. The gear structure and the rotating column are both located within the receiving cavity. The indicator dial and the scale dial are sequentially arranged on the outer side of the cover, with the indicator dial positioned between the scale dial and the cover. The rotating column passes through the cover from the inside out and drives the indicator dial to rotate relative to the scale dial. This rational component layout improves the overall stability and reliability of the compass, and facilitates manufacturing and subsequent maintenance.

[0018] To better guide the elastic deformation region through the third through-slit while ensuring the stability of the dial installation, preferably, both the indicator dial and the dial are circular, with the diameter of the dial being larger than that of the indicator dial. The cover has a spiral-shaped lifting ramp that fits the outer circumferential end face of the dial. The cover also has a guide block that supports the indicator dial and guides the elastic deformation region through the third through-slit. The design of the lifting ramp and guide block optimizes the operation of the reading structure, ensures accurate scale indication by the visible markings, and improves product performance.

[0019] To ensure more accurate readings and facilitate precise adjustment of the compass leg distance by the user, preferably, the circumferential edge of the scale dial forms an exposed annular area, which is not covered by the upper elastic deformation area. The scale values ​​are evenly distributed along the circumference of the annular area, and the visible marks point to the corresponding scale values ​​on the annular area. Furthermore, the spacing between adjacent scale values ​​corresponds linearly to the change in leg distance. This precise scale layout and linear correspondence allow users to accurately control the compass leg distance, meeting various drawing needs.

[0020] To ensure stable transmission between the rotating column and the positioning foot or rotating foot, and reliable connection between the rotating column and the indicator dial, preferably, the rotating column includes a meshing part and a driving part, the outer periphery of the meshing part is provided with a gear, and at least one of the positioning foot or rotating foot is provided with teeth that mesh with the gear;

[0021] The drive unit has a polygonal cross-section, and a polygonal hole matching the cross-section of the drive unit is provided through the center of the indicator disc. The combination of gears and the polygonal structure ensures the accuracy and stability of power transmission, improving the overall performance of the compass.

[0022] To further improve the stability of the rotating column and ensure the coordinated operation of all components of the compass, preferably, the rotating column has a first connecting shaft and a second connecting shaft at both ends, respectively. The cavity contains a first connecting hole for the first connecting shaft to rotate, and the dial has a second connecting hole for the second connecting shaft to rotate. This design of double connecting shafts and corresponding connecting holes enhances the stability of the rotating column, reduces wobbling during rotation, and ensures the normal use of the compass.

[0023] Compared with existing technologies, the advantages of this invention are as follows: By setting a rotatable rotating column on the compass head and driving it to the positioning foot or rotating foot, and by setting a reading module on the compass head, the indicating component of the reading module is linked to the rotating column, while the scale component is fixed to the compass head. When the positioning foot and the rotating foot rotate relative to each other, the rotating column can be driven to rotate synchronously, thereby driving the indicating component to rotate relative to the scale component, thus directly displaying the real-time distance between the positioning foot and the rotating foot. During the drawing process, the user does not need to manually adjust the radius with a ruler like with traditional compasses, simplifying the operation steps, reducing errors caused by repeated adjustments, and improving drawing efficiency and accuracy. In addition, since this invention only uses a simple mechanical structure drive, unlike some electronic compasses that rely on electronic components, it avoids the problems of high cost, susceptibility to electromagnetic interference, and limited service life of electronic components, reducing production costs. It can be used stably in various complex environments, has high measurement accuracy, and is durable, allowing users to draw circles more conveniently and accurately. Attached Figure Description

[0024] Figure 1 This is a three-dimensional structural diagram of this embodiment (with the compass in the closed state);

[0025] Figure 2 This is a three-dimensional structural diagram of this embodiment (the compass is in the measurement and use state, where A shows the visible mark formed by the indicator on the upper surface of the scale).

[0026] Figure 3 This is a three-dimensional exploded view of this embodiment;

[0027] Figure 4 This is a three-dimensional structural diagram of the transmission column in this embodiment;

[0028] Figure 5 This is a three-dimensional structural diagram of the indicator dial in this embodiment. Detailed Implementation

[0029] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0030] Figures 1-5 The diagram shown is a schematic diagram of this embodiment. The compass that can display the distance of the feet in this embodiment mainly includes a compass head 1, a positioning foot 2, a rotating foot 3, a rotating column 4, and a reading module 5. The specific structure of each component and the connection method between them will be described in detail below.

[0031] Compass head 1: Reference Figures 1 to 3 As shown, the compass head 1 includes a base 11 and a cover 12 that fit together. The base 11 and the cover 12 together form a receiving cavity 1a, which is used to install and accommodate other important components of the compass, such as the gear structure 2a and the rotating column 4. The base 11 has a first connecting hole 1a1 inside for the first connecting shaft 4c of the rotating column 4 to rotate, providing stable support and a base for rotation of the rotating column 4. The cover 12 has two key structures. First, it has a spiral-shaped lifting slope 12a that fits the outer circumferential end face of the dial 5b. Its function is to position and support the dial 5b during installation, ensuring the stability and accuracy of the dial 5b installation and allowing the dial 5b to better cooperate with the indicator dial 5a. Second, it has a guide block 12b that holds the indicator dial 5a and guides the elastic deformation area 5a3 through the third through-slit 5b2. This ensures that during the rotation of the indicator dial 5a, the elastic deformation area 5a3 can accurately pass through the third through-slit 5b2 of the dial 5b and form a visible mark.

[0032] Positioning foot 2 and rotating foot 3: Reference Figures 1 to 3As shown, the positioning foot 2 and the rotating foot 3 are hinged to the compass head 1 in a rotatable manner via a pin structure. Specifically, their relative rotation is achieved through a meshing gear structure 2a at their tops. Simultaneously, at least one of the positioning foot 2 or the rotating foot 3 has teeth 2b that mesh with the outer peripheral gear 4a1 of the meshing part 4a of the rotating column 4. This gear meshing connection allows the relative rotation of the positioning foot 2 and the rotating foot 3 to be accurately transmitted to the rotating column 4, causing the rotating column 4 to rotate synchronously.

[0033] Rotating column 4: Reference Figure 5 As shown, the rotating column 4 is a key component connecting the positioning foot 2, the rotating foot 3, and the reading module 5. It includes a meshing part 4a and a driving part 4b. A gear 4a1 is provided on the outer periphery of the meshing part 4a, meshing with the teeth 2b on the positioning foot 2 or the rotating foot 3 to transmit power. The driving part 4b has a polygonal cross-section, which mates with a polygonal hole 5a4 that is fitted through the center of the indicator dial 5a and matches the cross-section of the driving part 4b. This polygonal fit ensures that the rotating column 4 can drive the indicator dial 5a to rotate synchronously, ensuring stable transmission and preventing slippage. The rotating column 4 has a first connecting shaft 4c and a second connecting shaft 4d at its two ends. The first connecting shaft 4c rotatably adapts to the first connecting hole 1a1 inside the receiving cavity 1a, and the second connecting shaft 4d rotatably adapts to the second connecting hole 5b4 on the dial 5b, further ensuring the stability and accuracy of the rotating column 4 during rotation.

[0034] Reading module 5: Reference Figures 2 to 4 As shown, the reading module 5 includes an indicating component and a scale component. The indicating component mainly includes an indicating disk 5a, and the scale component mainly includes a scale disk 5b. The indicating disk 5a and the scale disk 5b are coaxially stacked, with the indicating disk 5a attached to the bottom of the scale disk 5b. The indicating disk 5a is a thin, elastically deformable sheet structure. A first through-slit 5a1 extending radially and a second through-slit 5a2 connected to the first through-slit 5a1 and extending circumferentially are provided on the disk surface. These two through-slits together divide the indicating disk 5a into an annular elastically deformable region 5a3. A polygonal hole 5a4 adapted to the driving part 4b of the rotating column 4 is provided at the center of the indicating disk 5a, allowing it to rotate relative to the scale disk 5b under the drive of the rotating column 4. The scale disk 5b is also a thin, elastically deformable sheet structure, coaxially arranged with the indicating disk 5a. The upper surface of the dial 5b has circumferentially distributed scale values ​​5b1, and a third through slit 5b2 extending radially and allowing the annular region 5b3 to pass through. The circumferential edge of the dial 5b has an exposed annular region 5b3, and the scale values ​​5b1 are evenly distributed circumferentially along the annular region 5b3, with the spacing between adjacent scale values ​​5b1 corresponding linearly to the change in foot distance.

[0035] The assembly process for each component is as follows: (Refer to...) Figure 3 As shown, the positioning foot 2 and the rotating foot 3 are meshed together via the gear structure 2a at the top and mounted on the base 11 of the compass head 1, ensuring they can rotate relative to each other. The rotating column 4 is placed into the receiving cavity 1a, so that the first connecting shaft 4c is fitted into the first connecting hole 1a1, and simultaneously the gear 4a1 of the meshing part 4a meshes with the teeth 2b on the positioning foot 2 or the rotating foot 3. The indicator dial 5a and the scale dial 5b are sequentially installed on the outside of the cover 12. First, the indicator dial 5a is mounted on the driving part 4b of the rotating column 4 through the polygonal hole 5a4, and then the scale dial 5b is mounted above the indicator dial 5a, so that the second connecting shaft 4d is fitted into the second connecting hole 5b4, and simultaneously the outer peripheral end face of the scale dial 5b is fitted onto the lifting inclined surface 12a of the cover 12. Finally, the cover 12 is fitted and installed onto the base 11, completing the assembly of the entire compass.

[0036] The working principle and measurement method of this compass need further explanation here, as described in detail below:

[0037] When a user needs to adjust the distance between the compass feet to draw circles of different radii, they manually rotate the positioning foot 2 or the rotating foot 3. Since the tops of the positioning foot 2 and the rotating foot 3 are connected by a meshing gear structure 2a, this relative rotation transmits power through the gear structure 2a. The relative rotation of the positioning foot 2 and the rotating foot 3 causes the rotating column 4 to rotate synchronously. The first connecting shaft 4c of the rotating column 4 is adapted to the first connecting hole 1a1 inside the receiving cavity 1a, and the second connecting shaft 4d is adapted to the second connecting hole 5b4 on the dial 5b. This ensures the stability and accuracy of the rotation of the rotating column 4, allowing power to be effectively transmitted from the positioning foot 2 and the rotating foot 3 to the rotating column 4. The drive part 4b of the rotating column 4 has a polygonal cross-section, which is adapted to the polygonal hole 5a4 at the center of the indicator dial 5a. When the rotating column 4 rotates, it causes the indicator dial 5a to rotate synchronously relative to the dial 5b.

[0038] The indicator dial 5a and the scale dial 5b are coaxially stacked, with the indicator dial 5a resting below the scale dial 5b. The indicator dial 5a is a thin, elastically deformable sheet structure. A first through-slit 5a1 and a second through-slit 5a2 on its surface divide it into an annular elastically deformable region 5a3. The scale dial 5b has a corresponding third through-slit 5b2. During rotation of the indicator dial 5a relative to the scale dial 5b, a guide block 12b on the cover 12 holds the indicator dial 5a, guiding the elastically deformable region 5a3 upwards through the third through-slit 5b2 and layering it onto the upper surface of the scale dial 5b, forming a visible mark corresponding to the scale value 5b1. (See reference [link to reference] for details.) Figure 2 As shown, Figure 2 As shown in Figure A, the visible markings formed by the indicator dial 5a on the upper surface of the scale dial 5b are as follows.

[0039] The upper surface of the dial 5b is circumferentially distributed with scale values ​​5b1. These scale values ​​5b1 are evenly distributed along the annular region 5b3 at the circumferential edge, and the spacing between adjacent scale values ​​5b1 corresponds linearly to the change in foot distance. A visible mark on the indicator dial 5a points to the corresponding scale value 5b1 on the annular region 5b3. By observing the scale value 5b1 pointed to by the visible mark, the user can directly read the real-time foot distance between the positioning foot 2 and the rotating foot 3, thus realizing the foot distance measurement function.

[0040] The lifting ramp 12a on the cover 12 fits onto the outer peripheral end face of the dial 5b, providing stable support and positioning for the dial 5b. This ensures the dial 5b remains accurately positioned during installation and use, preventing displacement and guaranteeing accurate readings. Furthermore, the surface color of the indicator 5a can differ from that of the dial 5b; for example, the surface color of the indicator 5a can be set to red or orange. This color difference creates a clear visual contrast, allowing users to more clearly and intuitively read the scale value 5b1 corresponding to the visible markings, further improving the convenience and accuracy of measurement.

[0041] In summary, the compass of this invention, which displays the distance between the feet, achieves the adjustment and measurement of the distance through a mechanical structure. It has the advantages of low cost, immunity to electromagnetic interference, high measurement accuracy, and durability, providing a reliable tool for drafting work.

[0042] It should be noted that in the description of this embodiment, the terms "front," "rear," "left," "right," "inner," "outer," "upper," and "lower," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are merely for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. The terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

Claims

1. A compass capable of displaying leg distance, comprising a compass head (1), positioning legs (2), and rotating legs (3), characterized in that: The positioning foot (2) and the rotating foot (3) are rotatably connected to the compass head (1), and the top of the positioning foot (2) and the top of the rotating foot (3) are respectively provided with mutually meshing gear structures (2a); The compass head (1) is provided with a rotatable rotating column (4), and the rotating column (4) is driven to at least one of the positioning foot (2) or the rotating foot (3). The relative rotation of the positioning foot (2) and the rotating foot (3) can drive the rotating column (4) to rotate synchronously. The compass head (1) is provided with a reading module (5). The reading module (5) includes an indicator component linked to the rotating column (4) and a scale component on the compass head (1). The indicator component rotates synchronously with the rotating column (4) and directly displays the real-time distance between the positioning foot (2) and the rotating foot (3) by changing its relative position with the scale component.

2. The compass capable of displaying leg distance according to claim 1, characterized in that: The indicating component includes an indicating disk (5a), and the scale component includes a scale disk (5b). The indicating disk (5a) and the scale disk (5b) are coaxially arranged. The indicating disk (5a) can rotate relative to the scale disk (5b) under the drive of the rotating column (4). The upper surface of the scale disk (5b) is formed with scale values ​​(5b1) distributed circumferentially. The indicating disk (5a) is formed with a visible mark that can point to the scale value (5b1).

3. The compass capable of displaying leg distance according to claim 2, characterized in that: The indicator dial (5a) and the scale dial (5b) are arranged coaxially and stacked, with the indicator dial (5a) attached to the bottom of the scale dial (5b). Both the indicator dial (5a) and the scale dial (5b) are elastically deformable thin sheet structures; The indicator disk (5a) has a first through-slit (5a1) extending radially and a second through-slit (5a2) connected to the first through-slit (5a1) and extending circumferentially. The first through-slit (5a1) and the second through-slit (5a2) together divide the indicator disk (5a) into an annular elastic deformation region (5a3). The corresponding position of the dial (5b) is provided with a third through slit (5b2) that extends radially and allows the annular area (5b3) to pass through. When the indicator (5a) is rotated relative to the scale (5b), the elastic deformation area (5a3) can pass upward through the three through-slits (5b2) through elastic deformation and be exposed on the upper surface of the scale (5b) to form a visible mark corresponding to the scale value (5b1).

4. The compass capable of displaying leg distance according to claim 2, characterized in that: The surface color of the indicator (5a) is different from the surface color of the scale (5b). The visible marks formed on the indicator (5a) can form a visual contrast with the scale value (5b1) of the scale (5b) through the color difference, so as to enhance the readability.

5. The compass capable of displaying leg distance according to claim 3, characterized in that: The compass head (1) includes a base (11) and a cover (12) that are adapted to each other. The base (11) and the cover (12) together form a receiving cavity (1a). The gear structure (2a) and the rotating column (4) are both located in the receiving cavity (1a). The indicator disk (5a) and the scale disk (5b) are arranged sequentially on the outer side of the cover (12), and the indicator disk (5a) is located between the scale disk (5b) and the cover (12). The rotating column (4) passes through the cover (12) from the inside to the outside and drives the indicator disk (5a) to rotate relative to the scale disk (5b).

6. The compass capable of displaying leg distance according to claim 5, characterized in that: Both the indicator dial (5a) and the scale dial (5b) are circular, and the diameter of the scale dial (5b) is larger than the diameter of the indicator dial (5a). A spiral-shaped lifting slope (12a) is formed on the cover (12) and can fit the outer peripheral end face of the scale dial (5b). A guide block (12b) is also formed on the cover (12) to hold the indicator dial (5a) and guide the elastic deformation area (5a3) through the third through-slit (5b2).

7. The compass capable of displaying leg distance according to claim 6, characterized in that: The dial (5b) has an exposed annular area (5b3) formed on its circumferential edge. The annular area (5b3) is not covered by the upper elastic deformation area (5a3). The scale values ​​(5b1) are evenly distributed around the annular area (5b3). The visible mark points to the corresponding scale value (5b1) on the annular area (5b3). The spacing between adjacent scale values ​​(5b1) corresponds linearly to the change in foot distance.

8. The compass capable of displaying leg distance according to any one of claims 2 to 7, characterized in that: The rotating column (4) includes a meshing part (4a) and a driving part (4b). The outer periphery of the meshing part (4a) is provided with a gear (4a1). At least one of the positioning foot (2) or the rotating foot (3) is provided with teeth (2b) that mesh with the gear (4a1). The drive unit (4b) has a polygonal cross-section, and the center of the indicator disc (5a) is provided with a polygonal hole (5a4) that matches the cross-section of the drive unit (4b).

9. The compass capable of displaying leg distance according to claim 5, characterized in that: The rotating column (4) has a first connecting shaft (4c) and a second connecting shaft (4d) at its two ends respectively. The cavity (1a) has a first connecting hole (1a1) for the first connecting shaft (4c) to rotate and adapt. The dial (5b) has a second connecting hole (5b4) for the second connecting shaft (4d) to rotate and adapt.

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