Circular diameter direct reading measuring scale and circular diameter measuring method

Abstract

The present application relates to the field of industrial measurement technology, and provides a circle diameter direct reading measuring scale and a circle diameter measuring method, which comprise a reference measuring arm with a preset length, and a reading measuring arm connected at a fixed angle with the reference measuring arm; a nonlinear scale is arranged on the reading measuring arm, the nonlinear scale is calculated based on a geometric function relationship between the preset length and the diameter of a target circle, and the diameter value of the target circle is directly marked. The present application automatically positions the diameter direction by using the geometric constraint of the fixed angle and the circumference, eliminates the positioning error of finding the diameter direction by human, at the same time, the side length relationship is materialized as a physical scale distance by the nonlinear scale, and the diameter value is directly marked, one-time direct reading of the diameter is realized, calculation error and cumbersome steps are eliminated, and the measuring accuracy and efficiency are significantly improved.

Description

Technical Field

[0001] This invention relates to the field of industrial measurement technology, specifically to a measuring ruler for direct reading of circle diameter and a method for measuring circle diameter. Background Technology

[0002] Currently, in the field of industrial measurement, the diameter measurement of ring-shaped or tubular objects typically employs tools such as perforated rulers, vernier calipers, expansion gauges, or ordinary measuring tapes and rulers. However, existing measuring tools have significant drawbacks in practical applications: perforated rulers, while highly accurate, have extremely small measuring ranges; expansion gauges are accurate but expensive and inconvenient to carry; vernier calipers, when measuring inner diameters, are prone to significant human-induced errors and are not easy to determine the true diameter direction; ordinary measuring tapes and rulers, while portable and inexpensive, also struggle to accurately determine the diameter direction, leading to excessive measurement errors. In summary, existing technologies for measuring the diameter of circular objects generally suffer from difficulties in accurately determining the diameter direction, introducing large positioning errors, and requiring secondary calculations or complex readings. Therefore, there is an urgent need for a tool that can directly determine the diameter direction and provide direct readings of the measurement results. Summary of the Invention

[0003] To address the problems of existing technologies that make it difficult to accurately locate the diameter direction, resulting in large errors and the need for secondary calculations, this application proposes a direct diameter reading measuring ruler and a diameter measurement method. By using a fixed angle to automatically locate the diameter direction and directly mapping the reading through a non-linear scale, the application aims to eliminate positioning errors and calculation steps, thereby improving measurement accuracy and efficiency.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A direct diameter reading measuring ruler for circles includes: a reference measuring arm having a preset length; and a reading measuring arm connected at a fixed angle to the reference measuring arm. The reading measuring arm is provided with a non-linear scale, which is calculated based on the geometric function relationship between the preset length and the diameter of the target circle, and directly marks the diameter value of the target circle.

[0006] The above solution uses a reference measuring arm of preset length and a reading measuring arm connected to it at a fixed angle. During measurement, the diameter direction is automatically located by utilizing the geometric constraints of the fixed angle and the circumference, eliminating the positioning error caused by manually searching for the diameter direction. At the same time, a non-linear scale calculated based on geometric function relationships is set on the reading measuring arm and the diameter value is directly marked, allowing the measurer to directly read the diameter of the target circle from the scale, eliminating the secondary calculation step and significantly improving measurement accuracy and efficiency.

[0007] Optionally, the fixed-angle connection is a right angle.

[0008] Optionally, the scale interval of the nonlinear scale gradually changes along the extension direction of the reading measuring arm.

[0009] Optionally, the marked value of the nonlinear scale and the physical distance on the reading measuring arm satisfy the following mapping relationship: the physical distance is equal to the square root of the difference between the square of the marked value and the square of the preset length.

[0010] Optionally, both the reference measuring arm and the reading measuring arm are provided with non-linear scales that directly mark the diameter value of the target circle, forming a dual-range measuring area.

[0011] Optionally, the non-linear scale on the reference measuring arm increases outward from the fixed angle connection position to form a small-range measurement area; the non-linear scale on the reading measuring arm increases outward from the fixed angle connection position to form a large-range measurement area.

[0012] Optionally, the preset length of the reference measuring arm is 1 cm or 5 cm.

[0013] Optionally, the inner side of the reference measuring arm and / or the reading measuring arm is provided with equally spaced linear graduations.

[0014] In addition, the present invention also provides a method for measuring the diameter of a circle using a direct reading measuring ruler, comprising: placing the fixed angle connection position of the reference measuring arm and the reading measuring arm and the endpoint of the reference measuring arm on the circumference of the target circle to automatically locate the diameter direction of the target circle by the fixed angle; and directly reading the diameter value marked on the nonlinear scale through the intersection of the reading measuring arm and the circumference of the target circle.

[0015] Optionally, the measurement positioning method for different ranges includes: when measuring a small diameter, placing the fixed angle connection position and a specific scale point on the reading measuring arm on the circumference of the target circle; when measuring a large diameter, placing the fixed angle connection position and the end point of the reference measuring arm on the circumference of the target circle.

[0016] Beneficial effects:

[0017] 1. By using the fixed-angle connection structure between the reference measuring arm and the reading measuring arm, during measurement, the fixed-angle connection position only needs to be aligned with the end point of the reference arm to automatically determine the diameter direction using the geometric principle of the inscribed right triangle. This avoids the positioning error caused by manually finding the diameter position in existing technologies, and significantly improves the accuracy and reliability of the measurement.

[0018] 2. The non-linear scale on the reading measuring arm is calculated based on the geometric function relationship between the preset length and diameter (such as the Pythagorean theorem). This materializes the side length relationship that originally required secondary calculation into the physical scale distance on the ruler surface and directly marks the diameter value, realizing one-time direct reading of the diameter, eliminating calculation errors and cumbersome steps, and greatly improving measurement efficiency.

[0019] 3. By setting non-linear scales on both arms, a dual-range measurement area is formed, which expands the measurement range of a single tool; at the same time, the equally spaced linear scales on the inner side retain the measurement function of an ordinary ruler, improving the tool's practicality and cost-effectiveness. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of the circle diameter direct reading measuring ruler according to an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the positioning measurement of the circle diameter measurement method according to an embodiment of the present invention;

[0022] Among them, 1-reference measuring arm, 2-reading measuring arm, 3-fixed angle connection position, 4-non-linear scale, 5-linear scale, 6-reference measuring arm end point. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0024] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention.

[0025] Example 1:

[0026] like Figure 1 and Figure 2 As shown, this embodiment provides a direct-reading measuring ruler for circle diameter. The measuring ruler includes a reference measuring arm 1 and a reading measuring arm 2.

[0027] The reference measuring arm 1 has a preset length.

[0028] Specifically, the preset length refers to the fixed physical distance on the reference measuring arm 1 from the fixed angle connection position 3 to the endpoint 6 of the reference measuring arm. This preset length serves as the geometric calculation benchmark for the entire measuring ruler and is determined during manufacturing; it cannot be arbitrarily extended, retracted, or changed. It should be understood that although specific preset length values ​​will be listed in subsequent embodiments, the selection of the preset length is not limited to a particular value. It can be flexibly set according to the actual measurement range requirements, scale distribution density, or portability requirements, as long as it can participate in the construction of geometric function relationships as a known side during measurement.

[0029] The reading measuring arm 2 is connected to the reference measuring arm 1 at a fixed angle.

[0030] Specifically, the reading measuring arm 2 and the reference measuring arm 1 intersect at a fixed angle connection point 3, forming a fixed angle. This angle is fixed after manufacturing, ensuring that the relative positions of the two arms will not rotate or shift. This embodiment, through this fixed angle connection structure, utilizes the geometric constraints between the fixed angle and the circumference of the target circle during measurement to automatically locate the diameter direction of the target circle. It is important to emphasize that the "fixed angle" here is not limited to a right angle (i.e., 90 degrees). Although a right angle is a typical and preferred angle choice for automatically locating the diameter direction in the geometric principle of an inscribed triangle, in other embodiments, the fixed angle can also be other specific fixed angles, as long as the fixed angle can form a definite geometric constraint relationship with the circumference, thereby deriving the mapping relationship between the diameter and the side length.

[0031] The reading measuring arm 2 is provided with a non-linear scale 4, which is calculated based on the geometric function relationship between the preset length and the diameter of the target circle, and directly marks the diameter value of the target circle.

[0032] Specifically, the non-linear scale 4 is the core functional element of this embodiment, breaking away from the traditional layout of equally spaced linear scales on a ruler. The physical spacing and numerical values ​​of this scale 4 are not arbitrarily set, but are derived mathematically based on the geometric function relationship between the preset length of the reference measuring arm 1 and the diameter of the target circle. During measurement, when the fixed-angle connection position 3 and the endpoint 6 of the reference measuring arm are aligned with the circumference of the target circle, the physical position corresponding to the intersection of the reading measuring arm 2 and the circumference of the target circle reflects the diameter of the target circle. The non-linear scale 4 materializes this abstract geometric function mapping relationship into physical scale distances on the ruler surface, and directly marks the diameter value of the target circle at this physical position (e.g., directly marking diameter values ​​such as "2cm" or "5cm," rather than marking side length values). It should be understood that the "geometric function relationship" here is not limited to the Pythagorean theorem. Although the Pythagorean theorem is the most direct mathematical expression in the case of a right-angle connection, when the fixed angle is other angles, this geometric function relationship can correspond to the sine theorem, cosine theorem, or other trigonometric function derivation formulas. Any function that is derived based on a preset length and fixed angle and can establish a one-to-one mapping relationship between the physical distance on the reading measuring arm and the diameter of the target circle falls within the category of "geometric function relationship" covered by this embodiment.

[0033] Through the above scheme, this embodiment establishes a diameter measurement architecture. Its working mechanism is as follows: First, by connecting the reference measuring arm 1 and the reading measuring arm 2 at a fixed angle, a measurement frame with fixed geometric constraints is formed in the physical structure. When two specific points of this frame are aligned with the circumference, the geometric properties of the fixed angle force the reading measuring arm 2 to automatically align with or intersect in the diameter direction, thereby eliminating the positioning error caused by manually searching for the diameter direction in the prior art. Second, the geometric function relationship is materialized and the diameter value is directly marked through the nonlinear scale 4. The measurer no longer needs to read the side length and perform secondary calculations or look up tables, realizing a direct mapping reading from the physical intersection point to the diameter value, eliminating calculation steps and calculation errors.

[0034] Example 2:

[0035] Based on Example 1, this example further explains the specific angle of the fixed-angle connection and the physical and mathematical nature of the nonlinear scale 4.

[0036] First, the fixed-angle connection is a right angle.

[0037] Specifically, combined Figure 1As shown, when the reference measuring arm 1 and the reading measuring arm 2 form a 90-degree angle at the fixed-angle connection position 3, the entire measuring ruler constitutes a right-angled triangular measuring frame. The reason this embodiment preferably limits the fixed angle to a right angle is due to the geometric necessity stemming from Thales' theorem: in a circle, the inscribed triangle formed with the diameter of the circle as its hypotenuse is necessarily a right-angled triangle, and the right-angle vertex must fall on the circumference of the circle. This means that when the operator places the right-angle vertex (i.e., the fixed-angle connection position 3) and the endpoint 6 of the reference measuring arm onto the circumference of the target circle, the extension direction of the reading measuring arm 2 will automatically and uniquely point to the diameter direction of the circle, without requiring any additional angle calculations or direction finding by the operator. It should be understood that although Embodiment 1 emphasizes that the fixed angle is not limited to a right angle, a right angle is the optimal and only angle selection that does not require additional trigonometric function calculations to achieve the core effect of "automatically locating the diameter direction." It simplifies the complex geometric positioning constraints into the most intuitive physical contact action, thereby eliminating the positioning error caused by manually searching for the diameter direction at the physical operation level.

[0038] Subsequently, based on the fixed angle being a right angle, the scale spacing of the nonlinear scale 4 gradually changes along the extension direction of the reading measuring arm 2.

[0039] Specifically, combined Figure 2 As shown, the distribution of nonlinear graduations 4 on the ruler surface is not a constant, equidistant arrangement like that of a regular ruler. Instead, it exhibits a physical arrangement that gradually increases outward from the fixed-angle connection position 3. This phenomenon of gradually increasing spacing is essentially determined by the nonlinearity of the increment of the side length of the right triangle. Under the constraints of right-angle geometry, as the diameter of the target circle (i.e., the hypotenuse) increases linearly, the increment of the distance between the corresponding physical intersection points (i.e., the right-angled sides) on the reading measuring arm 2 is not linear, but rather exhibits the growth characteristics of a square root function. Therefore, the graduation spacing inevitably appears as a gradually increasing visual feature on the physical ruler surface. This change in physical spacing directly materializes the abstract concept of "nonlinearity" into a visible graduation arrangement.

[0040] Furthermore, the marked value of the nonlinear scale 4 and the physical distance on the reading measuring arm 2 satisfy the following mapping relationship: the physical distance is equal to the square root of the difference between the square of the marked value and the square of the preset length.

[0041] Specifically, within the framework of right-angled connections, the preset length of the reference measuring arm 1 corresponds to one leg of a right triangle, the physical distance on the reading measuring arm 2 corresponds to the other leg, and the diameter of the target circle corresponds to the hypotenuse. According to the Pythagorean theorem, the square of the hypotenuse is equal to the sum of the squares of the two legs. Therefore, it is deduced that the physical distance on the reading measuring arm 2 is equal to the square root of the square of the diameter mark minus the square of the preset length. This formula eliminates the tedious step of "reading the side length and then calculating the diameter" that the measurer would normally need to perform, completing the calculation directly in the manufacturing process. It directly materializes the calculation result into a physical scale distance on the ruler, and marks the diameter value at that distance.

[0042] To demonstrate how this mapping relationship materializes abstract geometric relationships into ruler-like scales, specific numerical values ​​are used for illustration. When the preset length of the reference measuring arm 1 is set to 1 cm, if the diameter of the target circle is marked as 2 cm, according to the mapping formula above, the corresponding physical distance on the reading measuring arm 2 is √(2²-1²)=√3≈1.732 cm; if the diameter is marked as 3 cm, the physical distance is √(3²-1²)=√8≈2.828 cm; if the diameter is marked as 4 cm, the physical distance is √(4²-1²)=√15≈3.873 cm; if the diameter is marked as 5 cm, the physical distance is √(5²-1²)=√24≈4.899 cm. Similarly, when the preset length is set to 5 cm, if the diameter is 10 cm, the physical distance is √(10²-5²)=√75≈8.660 cm; if the diameter is 15 cm, the physical distance is √(15²-5²)=√200≈14.142 cm; and if the diameter is 20 cm, the physical distance is √(20²-5²)=√375≈19.365 cm. From the above data, it is clear that due to the square root mapping relationship of the Pythagorean theorem, the scale spacing gradually increases with the increase of the diameter, thus forming the aforementioned non-linear scale with gradually changing spacing on the physical scale surface.

[0043] It should be understood that the fixed angle is not limited to right angles. The following example, with a fixed angle of 60°, provides specific geometric derivation and scale mapping data to demonstrate that a fixed angle that is not right angle can also be directly read as a diameter through geometric constraints.

[0044] When the reference measuring arm 1 and the reading measuring arm 2 form a 60° angle at the fixed-angle connection position 3, the entire measuring ruler constitutes a triangular measuring frame with a fixed apex angle of 60°. Similar to the right-angle case, when the operator aligns the fixed-angle connection position 3 and the endpoint 6 of the reference measuring arm with the circumference of the target circle, the intersection of the reading measuring arm 2 and the circumference of the target circle can also reflect the diameter information of the target circle. The difference is that in the right-angle case, the extension direction of the reading measuring arm 2 is automatically aligned with the diameter direction (i.e., automatic positioning in the physical direction), while in non-right-angle cases such as 60°, although the reading measuring arm 2 does not extend along the diameter direction, the geometric constraint of the fixed angle still establishes a definite mapping relationship between the diameter and the side length, thereby allowing the diameter value to be read directly through the non-linear scale 4. In other words, "automatic positioning of the diameter direction" is manifested as automatic alignment of the physical direction in the right-angle case, and as automatic determination of the diameter value by geometric constraints in the non-right-angle case—the core mechanism of both cases is "the fixed angle provides a definite geometric constraint," only the manifestation of this determinism differs at different angles.

[0045] Specifically, within a 60° fixed-angle triangular frame, let the preset length of the reference measuring arm 1 be L, the physical distance from the fixed-angle connection position 3 on the reading measuring arm 2 to the intersection point of the circle be d, and the diameter of the target circle be D. Based on the geometric properties of an inscribed triangle, and using the combined cosine and sine theorems, the diameter D and the known side length satisfy the following general mapping relationship:

[0046]

[0047] The general mapping relationship between diameter D, preset length L, and physical distance d when the fixed angle is α. Here, α is the fixed angle of the fixed-angle connection, L is the preset length of the reference measuring arm, d is the physical distance on the reading measuring arm from the fixed-angle connection position to the intersection point of the circles, and D is the diameter of the target circle. This formula is derived by calculating the length of opposite sides using the law of cosines and then converting the chord length into a diameter using the law of sines.

[0048] When α = 60°, since cos60° = 1 / 2 and sin60° = √3 / 2, the above general relationship simplifies to:

[0049]

[0050] The simplified mapping formula for diameter D when the angle is 60° is obtained by substituting cos60°=1 / 2 and sin60°=√3 / 2 into the general formula.

[0051] Accordingly, when manufacturing the nonlinear scale 4, the above relationship needs to be inversely solved as a function of the physical distance d with respect to the diameter D, in order to determine the physical position of each diameter value on the scale surface. The inverse solution yields:

[0052] When α = 60°, the inverse formula simplifies to:

[0053]

[0054] The inverse formula for the physical distance d with respect to the diameter D when the angle is fixed at α is used to determine the physical scale position corresponding to each diameter value on the nonlinear scale. This formula is obtained by solving a quadratic equation based on a general mapping relationship, taking the positive root to ensure that the physical distance is positive.

[0055] When α = 60°, the inverse formula simplifies to:

[0056]

[0057] The simplified inverse formula for the physical distance d when the angle is 60°. This involves applying cos60° = 1 / 2 and sin60° = Substituting into the inverse solution formula, we obtain the physical scale position used to determine the nonlinear scale on the 60° fixed-angle measuring ruler.

[0058] The following verification is based on specific numerical values. When the preset length L = 1 cm and the fixed angle is 60°: If the diameter of the target circle D = 2 cm, the physical distance d on the reading measuring arm 2 is d = 1 / 2 + (√3 / 2)·√(2²-1²) = 0.5 + (√3 / 2)·√3 ≈ 0.5 + 1.5 = 2.0 cm; if the diameter D = 3 cm, d = 0.5 + (√3 / 2)·√(3²-1²) ≈ 0.5 + 2.449 ≈ 2.949 cm; if the diameter D = 4 cm, d = 0.5 + (√3 / 2)·√(4²-1²) ≈ 0.5 + 3.354 ≈ 3.854 cm; if the diameter D = 5 cm, d = 0.5 + (√3 / 2)·√(5²-1²) ≈ 0.5 + 4.243 ≈ 4.743 cm.

[0059] Similarly, when the preset length L = 5 cm and the fixed angle is 60°: if the diameter D = 10 cm, d = 2.5 + (√3 / 2)·√(10² - 5²) ≈ 2.5 + 7.5 ≈ 10.0 cm; if the diameter D = 15 cm, d = 2.5 + (√3 / 2)·√(15² - 5²) ≈ 2.5 + 12.247 ≈ 14.747 cm; if the diameter D = 20 cm, d = 2.5 + (√3 / 2)·√(20² - 5²) ≈ 2.5 + 16.793 ≈ 19.293 cm.

[0060] Through the above derivation and data, it is clear that in the case of a fixed angle of 60°, the scale spacing of the nonlinear scale 4 also exhibits the physical characteristic of gradually changing along the extension direction of the reading measuring arm 2, and there is also a definite mapping relationship between the diameter value and the physical distance, which can be materialized as scale markings on the ruler. This fully proves that regardless of whether the fixed angle is a 90° right angle or a 60° non-right angle, as long as the angle is a fixed value and can form a definite geometric constraint with the circumference, the mapping relationship between the diameter and the physical distance can be established through the corresponding trigonometric function derivation, thereby materializing it as a nonlinear scale 4 on the ruler and directly marking the diameter value. It should be understood that 60° is only one example of a non-right angle listed in this supplementary explanation. Other fixed angles such as 30°, 45°, and 120° are also feasible. Their respective mapping formulas can be obtained by simply replacing α in the above general formula with the corresponding angle value. This embodiment does not exhaustively list them.

[0061] Example 3:

[0062] Based on Example 1, this example further explains the range extension structure of the measuring ruler. Both the reference measuring arm 1 and the reading measuring arm 2 are provided with non-linear scales 4 that directly mark the diameter value of the target circle, forming a dual-range measuring area.

[0063] Specifically, combined Figure 2 As shown, traditional single-arm nonlinear scale layouts often only cover a single and limited measurement range. However, in actual industrial measurement scenarios, the diameter of the measured circle can range from a few millimeters to tens of centimeters. To broaden the measurement range without increasing the number and size of tools, this embodiment materializes nonlinear scales 4 on the outer edges of both the reference measuring arm 1 and the reading measuring arm 2. This dual-arm scale layout is not simply a functional repetition, but rather, through the coordinated operation of the two arm scales, it expands the originally single-range measuring ruler into a dual-range measuring tool with both small and large ranges, greatly enhancing the applicability and commercial value of a single tool.

[0064] Furthermore, the nonlinear scale 4 on the reference measuring arm 1 increases outward from the fixed angle connection position 3 to form a small range measurement area; the nonlinear scale 4 on the reading measuring arm 2 increases outward from the fixed angle connection position 3 to form a large range measurement area.

[0065] Specifically, when measuring a small diameter, the operator needs to place the fixed-angle connection position 3 and a specific scale point on the reading measuring arm 2 on the circumference of the target circle. At this time, the non-linear scale 4 on the reference measuring arm 1 intersects with the circumference to read the diameter. Since the positioning point is located on the reading measuring arm 2 near the fixed-angle connection position 3, the intersection point of the readings on the reference measuring arm 1 must also be close to the fixed-angle connection position 3. Therefore, the scale on the reference measuring arm 1 must increase outward from the fixed-angle connection position 3 to ensure that the scale for the small diameter falls within the effective measurement area. Conversely, when measuring a large diameter, the operator places the fixed-angle connection position 3 and the endpoint 6 of the reference measuring arm on the circumference. The intersection point on the reading measuring arm 2 will be far away from the fixed-angle connection position 3. Therefore, the scale on the reading measuring arm 2 must also increase outward from the fixed-angle connection position 3 to cover the reading range for the large diameter.

[0066] It should be understood that this bidirectional, outward-increasing layout from the connection point allows the operator to seamlessly switch between large and small measuring ranges without flipping the ruler or changing their grip; they can do so simply by altering the combination of positioning points that conform to the circumference. If a reverse layout were used, with the scale increments from the endpoint towards the fixed-angle connection position 3, it would lead to severe reading confusion: during small-range measurements, the intersection of the readings from the reference measuring arm 1 would be forced to fall near the endpoint 6. Since endpoint 6 itself serves as the positioning reference point for large-diameter measurements, if its vicinity is filled with small-diameter scales, it would cause physical interference between the positioning reference and the reading area. Furthermore, the reverse layout is incompatible with the switching logic between large and small measuring ranges. During large-diameter measurements, the intersection of the readings from the measuring arm 2 would be close to the fixed-angle connection position 3. If large-diameter scales are marked near the fixed-angle connection position 3, the small-range positioning point would overlap with the large-diameter scale, resulting in inaccurate readings. Therefore, increasing the scale outwards from the fixed-angle connection position 3 is the only reasonable direction for achieving interference-free switching between the two measuring ranges.

[0067] Example 4:

[0068] Based on Example 1, this example further explains the specific value of the preset length of the reference measuring arm 1 and the additional linear scale.

[0069] The preset length of the reference measuring arm 1 is 1 cm or 5 cm.

[0070] Specifically, the preset length serves as the reference parameter for calculating the nonlinear scale 4, and its value directly determines the scale distribution density and range of the measuring ruler. When the preset length is set to 1 cm, due to the extremely short physical length of the reference measuring arm 1, it can penetrate deep into the micro-aperture or narrow groove for close positioning, allowing the starting point of the small range of the nonlinear scale 4 to be reduced to an extremely low value, thereby achieving high-precision direct reading of the micro-circular diameter. When the preset length is set to 5 cm, the longer reference measuring arm 1 provides a wider geometric expansion space, allowing the nonlinear scale 4 on the reading measuring arm 2 to cover a larger diameter marking range, suitable for the measurement needs of large-diameter circular pipes and other conventional industrial pipes. It should be understood that 1 cm and 5 cm are only two typical and preferred numerical examples listed in this embodiment. In actual production and manufacturing, the preset length can be set to 2 cm, 3 cm, 10 cm, or other arbitrary fixed values ​​according to a specific target range, as long as the value can be used as a known side to participate in the construction of geometric function relationships and materialize into the corresponding nonlinear scale. This embodiment does not impose an absolute limitation on this.

[0071] Furthermore, the inner sides of the reference measuring arm 1 and / or the reading measuring arm 2 are provided with equally spaced linear scales 5.

[0072] Specifically, combined Figure 2 As shown, the linear scale 5 is located on the inner edge of the reference measuring arm 1 and the reading measuring arm 2, specifically on the inner side of the angle formed by the two arms. This linear scale 5 uses the same equidistant arrangement as a traditional ruler, with a constant scale spacing, and the marked values ​​represent the actual physical length distance. This layout of the inner edge linear scale 5 cleverly utilizes the unused edge space on the inner side of the measuring ruler. Without interfering with the core measurement function of the outer nonlinear scale 4, it retains the length measurement function of a regular ruler. This allows the operator to use the same tool to directly read the diameter of a circle via the outer nonlinear scale 4, and also to perform conventional straight-line distance measurement or marking operations via the inner linear scale 5, achieving multiple uses for one ruler and enhancing the tool's practicality and commercial value. It should be understood that the linear scale 5 can be located only on the inner edge of the reference measuring arm 1, only on the inner edge of the reading measuring arm 2, or simultaneously on the inner edges of both arms as shown in this embodiment. Its specific coverage area can be flexibly adjusted according to manufacturing costs and user needs.

[0073] Example 5:

[0074] Combination Figure 2 As shown in the figure, this embodiment provides a method for measuring the diameter of a circle using a measuring ruler that directly reads the diameter of the circle.

[0075] Step S100: Place the fixed angle connection position 3 of the reference measuring arm 1 and the reading measuring arm 2 and the endpoint 6 of the reference measuring arm 1 on the circumference of the target circle so as to automatically locate the diameter direction of the target circle by fixing the angle.

[0076] Specifically, when performing this step, the operator does not need to manually find the diameter direction of the circle by visual observation or repeated adjustments, as is done with traditional vernier calipers or rulers. Because the measuring ruler itself has the fixed-angle connection structure described in Embodiment 1, when the operator simultaneously aligns the fixed-angle connection position 3 (i.e., the vertex where the two arms intersect) and the reference measuring arm endpoint 6 with the circumference of the target circle, the geometric properties of the fixed angle form a forced constraint with the circumference. This constraint ensures that the extension direction of the reading measuring arm 2 necessarily passes through the straight line containing the diameter of the target circle, thus automatically and uniquely determining the diameter measurement direction at the physical action level. It should be understood that although this embodiment and subsequent embodiments mostly use right angles as examples to illustrate the necessity of this automatic positioning, when the fixed angle is another specific angle, as long as that angle can form a definite geometric mapping relationship with the circumference, the automatic positioning of the diameter direction can also be achieved by aligning the connection position and the endpoint with the circumference, without requiring any additional angle calculations or direction searching by the operator.

[0077] In step S200, the diameter value marked on the nonlinear scale 4 is directly read by measuring the intersection of the measuring arm 2 and the circumference of the target circle.

[0078] Specifically, after the automatic positioning at the fixed angle is completed in step S100, the reading measuring arm 2 and the circumference of the target circle will have a physical intersection point. The physical position of this intersection point on the ruler reflects the geometric function relationship between the diameter of the target circle and the preset length of the reference measuring arm 1. Since the nonlinear scale 4 has already materialized this abstract geometric function relationship into a physical scale distance on the ruler during manufacturing and directly marked the corresponding diameter value, the operator only needs to read the number on the nonlinear scale 4 at the intersection point to directly obtain the diameter of the target circle. For example, if the intersection point falls on the scale line marked "5cm", the diameter of the target circle is 5 centimeters. The operator does not need to read the physical distance of a side length and then perform secondary calculations or consult a reference table. This step, through the mechanism of "direct mapping of readings by nonlinear scale", moves the originally cumbersome and error-prone secondary calculation steps forward to the ruler manufacturing stage, simplifying the measurement process from a three-step process of "positioning - measuring side length - calculating diameter" to a two-step process of "fitting and positioning - direct reading", greatly improving measurement efficiency and eliminating calculation errors.

[0079] Example 6:

[0080] Building upon Example 5, this example further explains the measurement positioning methods for different measurement ranges. In actual industrial measurement scenarios, the diameter of the measured circle varies greatly, ranging from tiny apertures of a few millimeters to large pipes of tens of centimeters. A single-range positioning method often cannot simultaneously guarantee measurement accuracy and operational convenience for all sizes. Therefore, this example achieves seamless switching between large and small measurement ranges by changing the combination of positioning points that conform to the circumference.

[0081] The measurement positioning methods for different ranges include: when measuring a small diameter, placing the fixed angle connection position 3 and a specific scale point on the reading measuring arm 2 on the circumference of the target circle; when measuring a large diameter, placing the fixed angle connection position 3 and the endpoint 6 of the reference measuring arm on the circumference of the target circle.

[0082] Specifically, combined Figure 2 As shown, when the diameter of the target circle is small and falls within the small range covered by the nonlinear scale 4 of the reference measuring arm 1, the operator performs step S201: placing the fixed angle connection position 3 and the specific scale point on the reading measuring arm 2 on the circumference of the target circle. The specific scale point refers to the scale position on the reading measuring arm 2 corresponding to the preset length of the reference measuring arm 1. For example, when the preset length is 1 cm, the specific scale point is the nonlinear scale mark on the reading measuring arm 2 with a physical length of 1 cm from the fixed angle connection position 3; when the preset length is 5 cm, the specific scale point is the nonlinear scale mark with a physical length of approximately 5 cm. At this time, since both the fixed angle connection position 3 and the specific scale point are attached to the circumference of the small circle, the extension direction of the reference measuring arm 1 will pass through the diameter of the circle. The operator then directly reads the diameter value marked by the nonlinear scale 4 on the reference measuring arm 1 through the intersection of the reference measuring arm 1 and the circumference of the target circle. The logical necessity of this positioning method lies in the following: For a small-diameter circle, if endpoint 6 is still used as the positioning point, the preset length of the reference measuring arm 1 may be greater than the diameter of the small circle, causing endpoint 6 to be unable to fit on the inner side of the circumference, thus causing physical interference and failure to position; however, by using a specific scale point on the reading measuring arm 2 that is closer to the fixed angle connection position 3 as the positioning reference, the positioning span is effectively shortened, allowing the measuring ruler to penetrate into the small aperture to complete the fit and direct reading.

[0083] Conversely, when the diameter of the target circle is large and falls within the large range covered by the nonlinear scale 4 of the reading measuring arm 2, the operator performs step S202: placing the fixed angle connection position 3 and the endpoint 6 of the reference measuring arm on the circumference of the target circle. At this time, since the distance between the endpoint 6 and the fixed angle connection position 3 is the preset length of the reference measuring arm 1, for a large-diameter circle, this preset length is sufficient to act as a right-angled side of a right triangle fitting against the circumference without causing physical interference. The operator then directly reads the diameter value marked on the nonlinear scale 4 of the reading measuring arm 2 through the intersection of the reading measuring arm 2 and the circumference of the target circle. This positioning method avoids the problem of overly dense reading intersections and reduced resolution caused by a short positioning span when measuring large diameters, fully utilizing the relatively long physical extension space of the reading measuring arm 2 to expand the nonlinear scale, ensuring reading accuracy within a large range.

[0084] It should be understood that the large and small range switching positioning method described in this embodiment is based on different combinations of positioning points on the same measuring ruler. The operator does not need to change tools or flip the ruler; simply by changing the two reference points that fit the circumference, they can seamlessly cover the full range measurement needs from small to large. This switching logic not only protects the user's optimal usage behavior but also dynamically responds to the dual-range structure (as described in Embodiment 3) at the method level, preventing circumventers from evading infringement judgment by merely imitating the usage of a single range. Furthermore, although this embodiment uses right-angle connections and scale points at specific preset lengths as examples, in embodiments where the fixed angle is other angles or the preset length is other values, as long as the switching principle of "using short-span positioning points for small diameters and long-span positioning points for large diameters" is followed, it falls within the scope of defense covered by this embodiment.

[0085] Example 7:

[0086] To more clearly demonstrate the operational effectiveness and practical value of this invention in actual industrial environments, the typical applications of the aforementioned measuring ruler and method will be described in detail below, combined with specific industrial measurement scenarios. It should be understood that the following scenarios are merely illustrative and not restrictive, intended to prove that the technical solution of this invention can effectively solve the core pain point of accurately locating the diameter direction in the prior art.

[0087] Scenario 1: Measurement of the inner diameter of the O-ring seal in a hydraulic system (small diameter scenario).

[0088] In the maintenance and assembly of hydraulic systems, the dimensional accuracy of the O-ring seals directly determines the system's leak-proof performance. Assuming the target diameter of the O-ring being measured is approximately 2 cm, it falls into the typical small-diameter measurement category. If using existing vernier calipers to measure the inner diameter of this O-ring, the operator often needs to insert the calipers into an extremely small aperture and repeatedly adjust the caliper position based on experience to find the true diameter direction. This process is highly susceptible to human positioning errors due to caliper misalignment, leading to an underestimation of the diameter.

[0089] Using the measuring ruler and method of this invention, the operator can select a measuring ruler with a preset length of 1 cm for the reference measuring arm 1. During measurement, a small-range positioning step is performed: the operator simultaneously attaches the fixed-angle connection position 3 and a specific scale point on the reading measuring arm 2 (i.e., the scale position corresponding to a physical length of 1 cm) to the inner circumference of the O-ring. Due to the geometric constraint of the fixed angle, the extension direction of the reference measuring arm 1 automatically and uniquely points to the diameter direction of the O-ring, without any manual searching or adjustment. Subsequently, the operator directly observes the intersection point of the reference measuring arm 1 and the circumference of the O-ring, and reads the value marked on the non-linear scale 4 at the intersection point, instantly obtaining a direct reading result of approximately 2 cm in diameter. The entire process achieves "accurate positioning and error-free direct reading," eliminating the positioning errors and cumbersome operations caused by the difficulty in locating the diameter direction with vernier calipers in small-diameter measurements.

[0090] Scenario 2: Measurement of the outer diameter of industrial pipelines (large diameter scenario).

[0091] In the construction of chemical or water supply systems, it is often necessary to verify the actual outer diameter of industrial pipelines to ensure the sealing of flange connections. Assuming the target diameter of the industrial pipeline being measured is approximately 15 cm, which falls into the category of large-diameter measurements, using a standard measuring tape or ruler around the pipe is extremely difficult due to potential ellipticity deviations on the pipe surface or loose tape fit, making it very hard to find the true direction of the maximum diameter. Using vernier calipers, however, often has a range that cannot cover 15 cm and is cumbersome to operate.

[0092] Using the measuring ruler and method of this invention, the operator can select a measuring ruler with a preset length of 5 cm for the reference measuring arm 1. During measurement, a large-range positioning step is performed: the operator simultaneously attaches the fixed-angle connection position 3 and the end point 6 of the reference measuring arm to the outer circumference of the industrial pipe. At this time, the extension direction of the reading measuring arm 2 is automatically aligned with the pipe diameter direction due to right-angle geometric constraints. The operator then observes the intersection point of the reading measuring arm 2 and the outer circumference of the pipe, and directly reads the value marked on the non-linear scale 4 at the intersection point, thus obtaining a direct reading result of approximately 15 cm in diameter in one go. Compared with the pipe winding error of a tape measure or the range limitation of calipers, this solution also demonstrates the significant advantages of "accurate upon attachment and error-free direct reading," and the operation can be completed with one hand, greatly improving the efficiency and reliability of on-site measurement.

[0093] The comparison and verification of the two typical industrial scenarios above show that, whether facing O-rings with small apertures or large-sized industrial pipes, the present invention can effectively overcome the pain points of large positioning errors, the need for secondary calculations or cumbersome operations in the existing technology through the core mechanism of "fixed angle automatic positioning of diameter direction + nonlinear scale direct mapping reading", and realize high-precision direct reading measurement across the range.

[0094] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A measuring ruler for directly reading the diameter of a circle, characterized in that, include: The reference measuring arm has a preset length; The reading measuring arm is connected at a fixed angle to the reference measuring arm; The reading measuring arm is equipped with a non-linear scale, which is calculated based on the geometric function relationship between the preset length and the diameter of the target circle, and the diameter value of the target circle is directly marked.

2. The direct diameter reading measuring ruler according to claim 1, characterized in that, The fixed-angle connection is a right angle.

3. The direct diameter reading measuring ruler according to claim 2, characterized in that, The scale interval of the nonlinear scale gradually changes along the extension direction of the reading measuring arm.

4. The direct diameter reading measuring ruler according to claim 2, characterized in that, The marking value of the nonlinear scale and the physical distance on the reading measuring arm satisfy the following mapping relationship: The physical distance is equal to the square root of the difference between the square of the labeled value and the square of the preset length.

5. The direct diameter reading measuring ruler according to claim 1, characterized in that, Both the reference measuring arm and the reading measuring arm are provided with non-linear scales that directly mark the diameter value of the target circle, forming a dual-range measuring area.

6. The direct diameter reading measuring ruler according to claim 5, characterized in that, The non-linear scale on the reference measuring arm increases outward from the fixed angle connection position to form a small range measurement area. The non-linear scale on the reading measuring arm increases outward from the fixed angle connection position, forming a large range measurement area.

7. The direct diameter reading measuring ruler according to claim 1, characterized in that, The preset length of the reference measuring arm is 1 cm or 5 cm.

8. The direct-reading measuring ruler for circle diameter according to claim 1, characterized in that, The inner side of the reference measuring arm and / or the reading measuring arm is provided with equally spaced linear graduations.

9. A method for measuring the diameter of a circle using a measuring ruler that directly reads the diameter of the circle, characterized in that, include: The reference measuring arm and the reading measuring arm are connected at a fixed angle, and the end point of the reference measuring arm is placed on the circumference of the target circle to automatically locate the diameter direction of the target circle by a fixed angle. The diameter value marked on the non-linear scale is directly read by measuring the intersection of the measuring arm and the circumference of the target circle.

10. The method for measuring the diameter of a circle according to claim 9, characterized in that, Measurement positioning methods for different ranges include: When measuring a small diameter, the fixed angle connection position and the specific scale point on the reading measuring arm are placed on the circumference of the target circle; When measuring a large diameter, the fixed angle connection position and the endpoint of the reference measuring arm are placed on the circumference of the target circle.

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