Positioning tool and scribing method for scribing the reverse side of a steel sheet

Abstract

A positioning tool and a scribing method for the reverse side of a steel plate belong to the technical field of ship outfitting. The tool combines an elastic chuck with a hinged assembly with a micro high-precision bearing seat and a cylindrical pin shaft, so that the clamping mouth can smoothly swing within a limited angle in the normal direction of the plate. It can not only adapt to the thickness and surface state of the steel plate to achieve precise positioning with manual fine adjustment and stable positioning, but also realize quick and reliable fixing of the front and back sides through the detachable magnetic sheet with a boss. The positioning gap on the front side is convenient for aligning the reference line, and the positioning gap on the back side can be directly used as the scribing reference. The tool can obtain the accurate position of the back side through mechanical transmission after one-time alignment on the front side, and is suitable for various regular steel plates through the design of a large opening degree. The tool has compact overall structure, accurate positioning and simple operation, and greatly improves the efficiency and precision of scribing the reverse side of the steel plate.

Description

Technical Field

[0001] This invention relates to a positioning tool and marking method for marking lines on the reverse side of steel plates, which belongs to the field of ship outfitting technology. Background Technology

[0002] Reverse scribing is a critical process in shipbuilding design, primarily used to determine key markings such as assembly lines and baselines to ensure the accuracy of subsequent assembly and welding processes. Currently, common CNC equipment in the industry only supports front scribing, while reverse scribing still relies on manual operation. Its positioning accuracy directly affects the quality of critical stages such as section assembly and outfitting.

[0003] In actual operation, operators need to use a "line guide" tool to complete the line marking task. The specific process is as follows: Extend the datum line: Extend the datum line on the front of the component to the edges of both ends of the board; Thickness marking: Mark transition points along the thickness direction of the sheet material using an oil-based marker; Flip and Align: After flipping the board, use the alignment board to align the edge markings, confirm the position, and complete the assembly positioning.

[0004] Although the process can achieve basic functions, it still has the following obvious shortcomings in practical applications: the lack of a fixing mechanism leads to insufficient accuracy; the guide plate only contacts the edge of the steel plate through a simple clip, lacking a rigid fixing device. In actual operation, the tool is prone to slippage due to hand pressure or equipment vibration during marking; burrs or unevenness may exist on the edge of the steel plate, further reducing the bonding stability and causing displacement.

[0005] Currently, wire guide plates need to be matched to different sizes based on the thickness of the board material (e.g., 12mm, 20mm, 30mm, etc.), requiring a large number of different specifications of wire guide plates to be stocked on-site, increasing the costs of requisitioning, returning, and maintaining them. At the same time, operators frequently change tools, increasing the preparation time for each operation by an average of 5-8 minutes. Furthermore, non-standard board materials (such as those with varying thicknesses) cannot be adapted, requiring temporary manual adjustments, further impacting efficiency. The need for adapting to multiple board material specifications reduces efficiency. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides a positioning tool for scribing lines on the reverse side of steel plates. Through its unique structure, it effectively overcomes the limitations in applicability and unstable fixation caused by differences in plate thickness of the original tools, thereby significantly improving the accuracy and efficiency of scribing lines on the reverse side.

[0007] The technical solution adopted in this invention is: a positioning tool for scribing lines on the reverse side of a steel plate, the tool comprising a chuck assembly, a hinge assembly, a jaw assembly, and a fixing assembly; The chuck assembly is hinged to the jaw assembly via a hinge, and the fixing assembly is used to fix the jaw assembly to the steel plate; The clamp assembly uses a spring-loaded element to connect the upper handle and the lower handle of the clamp; The clamping assembly includes an upper clamping mouth and a lower clamping mouth. The upper clamping mouth is used to act on the front side of the steel plate, and the lower clamping mouth is used to act on the back side of the steel plate. Both the upper and lower clamping mouths are provided with positioning gaps. The positioning gap on the upper clamping mouth is used to align with the front reference line. The positioning gap on the lower clamping mouth is used to provide a scribing reference for the back side of the steel plate. The upper jaw and the upper handle of the clamp are connected by a hinge assembly, and the lower jaw and the lower handle of the clamp are connected by a hinge assembly or adopt an integrated structure. In the hinge assembly, the handle bushing is located at the end of the clamp handle, and the jaw plate bushing is located at the end of the jaw plate. The handle bushing and the jaw plate bushing are arranged alternately and connected in series by a cylindrical pin to hinge the clamp handle and the jaw plate. A bushing baffle is provided at the bottom of the jaw plate bushing. The bushing baffle extends and acts on the lower side of the clamp handle to limit the swing of the jaw plate. When the lower jaw and the lower handle of the clamp are connected by a hinge assembly, the clamp handle includes an upper handle and a lower handle, and the jaw plate includes an upper jaw and a lower jaw. When the clamp and the lower handle of the clamp are integrated into one piece, the clamp handle is the upper handle of the clamp, and the clamp plate is the upper clamp. The fixing component adopts a detachable magnetic sheet, and the magnetic sheet boss connects the magnetic sheet plates on both sides; the magnetic sheet boss is fastened in the width direction of the clamping assembly, and the upper clamping mouth and the lower clamping mouth are fixed to the front and back of the steel plate respectively by magnetic force.

[0008] Furthermore, the width of the positioning gap is 0.8mm ± 0.05mm.

[0009] Furthermore, the upper and lower handles of the clamp are respectively provided with anti-slip textures, and the contact surfaces of the upper and lower clamps with the steel plate to be marked are anti-slip surfaces.

[0010] Furthermore, markings are respectively provided on the upper handle and the lower handle of the clamp.

[0011] Furthermore, the maximum separation distance between the tips of the upper and lower clamps is not less than 40mm.

[0012] Furthermore, the width of the magnetic protrusion is 2mm-4mm larger than the width of the clamp.

[0013] Furthermore, the hinge assembly is a damping element.

[0014] A method of using the aforementioned positioning tool includes the following steps: S1. Using a right-angle ruler, precisely extend the reference line on the front side of the steel plate to be marked, which needs to transition to the back side, to both sides of the steel plate to be marked as the front reference line, and make short scribing marks on the edges. S2. Hold the positioning tool by the handle and straddle the edge of the steel plate to be marked, with the upper jaw on the front of the steel plate and the lower jaw on the back of the steel plate. At this time, when the jaw and the lower handle of the clamp are integrated into one piece, they are on the same plane; or when the lower jaw and the lower handle of the clamp are connected by a hinge assembly, the lower jaw and the lower handle of the clamp are on the same plane due to the limitation of the bushing stop, and the lower jaw is completely attached to the back of the steel plate to be scribed. The bushing stop between the upper jaw and the handle on the clamp is not in use at this time. The two are not in the same plane. The upper jaw is also fully attached to the front of the steel plate to be scribed, so that the positioning tool is initially fixed on the steel plate to be scribed by the elastic force of the elastic component. S3. Precise alignment of the front side, which includes the following sub-steps: S31. Look vertically upwards from the front of the steel plate to be marked, at the positioning gap of the clamping jaws. S32. Fine-tune the position of the positioning tool so that the positioning gap completely coincides with the front reference line mark; S33. Attach the detachable magnetic sheet to the front end of the upper and lower clamps so that it adheres to the steel plate to be scribed. S4. Draw lines on the reverse side, which includes the following sub-steps: S41. Keep the positioning tool fixed and move the operating position to the back of the steel plate to be marked; S42. Remove the pen from the positioning tool and place it into the positioning gap of the lower clamp to draw lines. The length of the short line segment drawn should be equal to the length of the gap. S5. Repeat the operation and connection, which includes the following sub-steps: S51. Pinch the upper handle and lower handle of the clamp to release the positioning tool. At this time, under the action of gravity, the upper jaw causes the bushing baffle to act on the lower side of the upper handle of the clamp, so that the upper jaw and the upper handle of the clamp are on the same plane, and the positioning tool leaves the current working position and moves to the other edge of the steel plate to be marked. S52. Repeat steps S3 and S4 to obtain another scribing line on the reverse edge of the steel plate to be scribed. S53. Using a ruler, connect the two lines on the reverse edge to obtain a complete reverse baseline that is perfectly parallel to the front baseline in space and corresponds precisely in position.

[0015] Compared with existing technologies, this invention has the following advantages: Existing guide plate solutions are essentially passive templates, with a structure consisting of only a wooden board of a specific thickness, relying on the gap between the edge of the steel plate to be marked and the groove of the guide plate for positioning. This structure lacks an independent clamping unit, maintaining contact solely through operator hand pressure or simple clips, and the positioning reference depends entirely on the physical contour of the edge of the steel plate to be marked. This device is structurally completely reconstructed into a dual-reference long-jaw clamp form. Core components include: a high-strength spring steel clamp body, precisely matched upper and lower jaws, a 0.8mm±0.05mm elongated positioning gap machined on the jaws, an anti-slip textured clamping surface, and a detachable magnetic fixing device. This structure transforms single thickness adaptation into opening self-adaptation.

[0016] The existing solution requires flipping the steel plate to be marked and performing a second alignment on the back to complete the positioning. This positioning tool eliminates the need for flipping; a single alignment on the front is sufficient to obtain the precise position on the back via mechanical transfer. The existing solution is designed for fixed thicknesses, requiring specialized tools for 12mm, 20mm, 30mm, etc. The positioning tool features an adaptive opening design, with a single clamp covering a plate thickness range of ≤40mm. Because the hinged assembly is in contact with the steel plate on the back, the upper clamp also contacts the front of the steel plate to be marked, making it suitable for non-standard gradient thickness plates as well. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of a traditional wire guide plate.

[0019] Figure 2 This is a schematic diagram of a positioning tool used for marking lines on the reverse side of a steel plate.

[0020] Figure 3 This is a schematic diagram of the positioning tool in Example 1.

[0021] Figure 4 This is a schematic diagram of the positioning tool in Example 2.

[0022] Figure 5 This is a schematic diagram of the detachable magnetic sheet.

[0023] Figure 6 This is a structural diagram of the hinge assembly.

[0024] In the diagram: 1. Upper clamp, 2. Positioning gap, 3. Lower clamp, 4. Removable magnetic sheet, 5. Hinge assembly, 5a. Cylindrical pin, 5b. Handle bushing, 5c. Clamp plate bushing, 5d. Bushing baffle, 6. Upper handle of clamp, 6a. Lower handle of clamp, 6b. Anti-slip texture, 7. Marking, 8. Elastic component, 9. Marking pen, 10. Front baseline, 11. Steel plate to be marked. Detailed Implementation

[0025] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms 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, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0027] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0028] This patent describes a specially designed mechanical clamp with a high-precision positioning reference. Each of the upper and lower clamping jaws (the parts that contact the steel plate to be marked) has a long, narrow, and highly parallel precision positioning gap machined into it. Working principle: (1) The operator first marks the baseline on the front of the steel plate and extends the line to the two sides of the steel plate to be marked.

[0029] (2) The marking clamp of the present invention is clamped on the edge of the steel plate, and the clamping mouth straddles the upper and lower surfaces of the steel plate to be marked.

[0030] (3) On the front of the steel plate, by fine-tuning the position of the clamp, the lower edge of the positioning gap of the upper clamp is precisely aligned with the baseline that has been extended to the edge on the front of the steel plate to be marked, and then the clamp is locked with the positioning magnetic sheet.

[0031] (4) At this time, due to the rigidity of the clamping structure, the positioning gap of the lower clamping mouth is completely aligned with the gap of the upper clamping mouth in the vertical direction.

[0032] (5) The operator only needs to insert the pen into the gap of the lower clamp and move it along the gap to draw a precise line on the edge of the reverse side of the steel plate that is completely perpendicular to the front baseline in three-dimensional space.

[0033] (6) Move the clamp to the other edge of the steel plate to be marked, and repeat the above operation to obtain the other end point corresponding to the reverse side. Connect the two points to obtain the complete reverse side line.

[0034] This principle ingeniously transforms the problem of three-dimensional spatial alignment into a simple operation of two-dimensional visual alignment on the front of the steel plate to be marked, and then uses the high-precision mechanical transmission of the device itself to automatically ensure the corresponding accuracy of the marking on the reverse side.

[0035] Overall size and shape Overall length: Designed to be 250mm. This length ensures sufficient clamping arm and operating space, while also facilitating portability and one-handed operation. The jaw section (from the rotation axis to the tip of the jaw) accounts for approximately 190mm, forming a "long jaw" feature to ensure it can span steel plates of varying thicknesses while maintaining a clear operating field of view.

[0036] Maximum clamp width: The main body is approximately 70mm wide to ensure structural rigidity. The handle can be widened to 100mm and features an ergonomically designed wave-shaped anti-slip texture to enhance grip comfort and stability when applying force.

[0037] Maximum opening: This refers to the maximum separation distance between the tips of the upper and lower jaws. To accommodate a wide range of steel plate thicknesses to be scribed, the maximum opening should be no less than 40mm, covering common operating ranges from thin plates (e.g., 6mm) to medium-thick plates (e.g., 35mm). For thicker steel plates, specific models can be manufactured by scaling up the design proportionally.

[0038] Main body material: The main body of the clamp (including the upper and lower clamping arms) is made of high-carbon spring steel (such as 65Mn) or high-quality alloy tool steel. These materials have high strength and high rigidity, ensuring minimal deformation of the clamp body under clamping conditions, thereby guaranteeing the relative positional accuracy of the upper and lower positioning gaps. At the same time, they also have good elasticity and fatigue strength, allowing the clamp to be repeatedly opened and closed and to be durable.

[0039] Positioning the gap cutting edge: The cutting edges on both sides of the long gap on the upper and lower jaws need to be locally ground and hardened or inlaid with carbide plates to achieve a hardness of HRC 55 or higher. The purpose is to prevent wear caused by repeated friction of the pen and to maintain the dimensional accuracy of the gap width and the sharpness of the edges over a long period of time.

[0040] Surface treatment: The entire surface is treated with rust prevention to improve corrosion resistance in humid and dusty environments during metal processing.

[0041] Shaft: Made of stainless steel pins to ensure smooth rotation and wear resistance.

[0042] Spring: Built-in helical compression spring provides stable clamping force. The spring force must meet the following requirements: it should be able to firmly clamp the steel plate to be marked (preventing slippage), but not so large that it would cause obvious indentations on the thin plate or make it difficult for the operator to work.

[0043] Positioning gap (core feature): Shape and Size: A long rectangular through-slot. The length is approximately 150mm, providing sufficient guide stroke for the scribing needle. Width is crucial for accuracy and must be strictly controlled; it is set at 0.8mm ± 0.05mm. This width is slightly larger than the standard scribing pen tip diameter (typically about 0.5mm), easily accommodating the scribing needle while effectively limiting lateral pen movement, ensuring the straightness of the scribing line.

[0044] Parallelism: On a single clamp, the long side of the gap must be strictly parallel to the clamping surface of the clamp (the plane in contact with the steel plate to be scribed), with the tolerance controlled within 0.02mm / 20mm.

[0045] Symmetry and Alignment: With the clamps closed, the two positioning gaps of the upper and lower jaws must be perfectly aligned in the direction perpendicular to the clamping surface. This is fundamental to the functionality of this device. The design requires that the projection overlap error of the center lines of the two gaps be less than 0.05mm. This needs to be ensured through mating machining (i.e., machining the gaps as a single piece after assembling the upper and lower jaws).

[0046] Logo: To facilitate quick identification and use, the words "TOP" or "Front Reference" can be laser-engraved near the gap on the upper jaw, and the words "BOTTOM" or "Reverse Scribing" can be engraved on the corresponding position on the lower jaw.

[0047] Detachable magnetic plates: The scribing clamp is equipped with two detachable magnetic plates. When not in use, the magnetic plates are attached to both sides of the positioning gap of the lower clamping nozzle for easy carrying. When in use, the magnetic plates are removed and attached to the steel plate to fasten the front end of the upper and lower clamping nozzles to fix the nozzles. Using magnetic attraction, no tools or extra steps are required. It is especially suitable for scribing at multiple points for a long time or in vibrating environments, and prevents any slight displacement caused by any reason.

[0048] To ensure the scribing clamp can hold steel plates of varying thicknesses, the positioning reference surfaces of both the upper and lower jaws achieve stress-free, full-fit contact with the steel plate surface. The jaw body is connected to a bearing housing via a precision tapered pin, forming a hinge that allows the jaw to swing at a limited angle perpendicular to the pin's axis (i.e., parallel to the normal direction of the steel plate to be scribed). When the jaw contacts the steel plate surface and needs to swing to adjust, it provides smooth resistance, preventing free wobbling and facilitating precise alignment by the operator from the front.

[0049] Pencil: Portable pencil, fixed at the base of the upper clip, can be removed by simply rotating it when in use.

[0050] Anti-slip handle: Ergonomically designed wave-shaped anti-slip texture enhances grip comfort and stability when applying force.

[0051] Clamping surfaces: The inner sides of the upper and lower clamps, in contact with the steel plate to be scribed, should be machined with fine mesh or straight anti-slip textures (texture depth approximately 0.1-0.2mm) to significantly increase the coefficient of friction and prevent the clamps from sliding laterally along the edge of the steel plate. The anti-slip textured area should avoid the vicinity of the positioning gaps to prevent affecting alignment observation.

[0052] 3. Detailed usage instructions and steps Preparation: Confirm that the steel plate edges are free of severe burrs, curled edges, or paint layers. Prepare the marking clamp, right-angle ruler, measuring tape, and the steel plate to be marked with the front reference line.

[0053] S1, Extended front baseline Using a right-angle ruler, precisely extend the baseline on the front of the steel plate to be marked, which needs to transition to the back, to both sides of the steel plate. Make clear short scribbles on the edges, which is the visual basis for subsequent alignment.

[0054] S2, Initial clamping Hold the marking clamp, pinching the handle with your thumb and forefinger, and straddle either edge of the steel plate to be marked. Ensure that the anti-slip surfaces of the upper and lower jaws are in contact with the front and back of the steel plate, respectively. Gently squeeze the handle to initially fix the clamp to the steel plate using spring force. At this point, the clamp is not precisely aligned and can slide.

[0055] S3. Precise alignment of the front side (key step) S31. Observe from above: Look vertically from above the front of the steel plate to be marked, towards the positioning gap of the clamping jaws.

[0056] S32. Fine-tuning the sliding: Use your other hand or slightly loosen your grip to push the clamp back and forth slightly to adjust the precision hinge so that the lower edge (or center line) of the long strip-shaped positioning gap on the upper clamping mouth completely coincides with the extended mark of the front reference line just drawn on the edge of the steel plate to be scribed.

[0057] S33. Visual Confirmation: Move your head left and right to observe from different angles to ensure there is no visible misalignment between the line and the edge of the gap. Since the gap is only 0.8mm wide, its edge itself can serve as an excellent "optical alignment".

[0058] S34. Locking and fixing: After confirming alignment, fasten the pre-removed positioning magnetic sheet to the front end of the upper and lower clamps, so that it is attracted to the steel plate and rigidly locked. At this time, the clamp and the steel plate to be marked have become a rigid whole.

[0059] S4, Reverse marking S41. Shift the operating surface: Keep the clamp fixed and move the operating position to the reverse side of the steel plate to be marked.

[0060] S42. Tool in place: Remove the pen and gently place it into the positioning gap of the lower clamp, so that the needle tip contacts the edge of the reverse side of the steel plate.

[0061] S43. Guided Marking: Smoothly move the marking pen along the entire length of the long, narrow gap. The lateral movement of the pen is strictly restricted by the two side walls of the gap, and straight lines can only be drawn along the length of the gap (i.e., perpendicular to the edge of the steel plate to be marked). The starting point of this line corresponds precisely to the starting point on the front side.

[0062] S44. Complete the endpoint: The length of the drawn short line segment is equal to the length of the gap (150mm), and it is clearly visible.

[0063] S5, Repeated Operations and Connections S51. Move to the other side: Release the clamp and move it to the other edge of the steel plate to be marked.

[0064] S52. Repeat alignment and scribing: Completely repeat steps two to four above to obtain another corresponding point scribing on the reverse edge of the steel plate to be scribed.

[0065] S53. Final connection: Using a ruler, connect the two lines on the reverse edge to obtain a complete reverse baseline that is completely parallel to the front baseline in space and precisely corresponds to it in position. Example 1

[0066] A positioning tool for scribing lines on the reverse side of a steel plate, characterized in that: the tool includes a chuck assembly, a hinge assembly 5, a jaw assembly, and a fixing assembly; the chuck assembly is hinged to the jaw assembly via a hinge, and the fixing assembly is used to fix the jaw assembly to the steel plate; The clamp assembly uses a spring element 8 to connect the upper handle 6 and the lower handle 6a of the clamp; The clamping assembly includes an upper clamping mouth 1 and a lower clamping mouth 3. The upper clamping mouth 1 is used to act on the front side of the steel plate, and the lower clamping mouth 3 is used to act on the back side of the steel plate. Both the upper clamping mouth 1 and the lower clamping mouth 3 are provided with positioning gaps 2. The positioning gap on the upper clamping mouth is used to align with the front reference line. The positioning gap on the lower clamping mouth is used to provide a scribing reference for the back side of the steel plate. The upper jaw 1 and the upper handle 6 of the clamp are connected by a hinge assembly 5, and the lower jaw 3 and the lower handle 6a of the clamp are connected by a hinge assembly 5. In the hinge assembly 5, the handle bushing 5b is located at the end of the clamp handle, and the jaw plate bushing 5c ​​is located at the end of the jaw plate. The handle bushing 5b and the jaw plate bushing 5c ​​are arranged alternately and connected in series by a cylindrical pin 5a, so that the clamp handle and the jaw plate are hinged. A bushing baffle 5d is provided at the bottom of the jaw plate bushing 5c. The bushing baffle 5d extends and acts on the lower side of the clamp handle to limit the swing of the jaw plate. The clamp handle includes an upper clamp handle 6 and a lower clamp handle 6a, and the jaw plate includes an upper jaw 1 and a lower jaw 3. The fixing component adopts a detachable magnetic sheet 4, and the magnetic sheet boss 4a connects the magnetic sheet plates 4b on both sides; the magnetic sheet boss 4a is fastened in the width direction of the clamping assembly, and the upper clamping mouth 1 and the lower clamping mouth 3 are fixed to the front and back of the steel plate respectively by magnetic force.

[0067] The width of positioning gap 2 is 0.8mm ± 0.05mm.

[0068] Anti-slip textures 6b are provided on the upper handle 6 and the lower handle 6a of the clamp, and the contact surfaces between the upper clamping mouth 1 and the lower clamping mouth 3 and the steel plate 11 to be marked are anti-slip surfaces.

[0069] Markings 7 are set on the upper handle 6 and the lower handle 6a of the clamp, respectively.

[0070] The maximum separation distance between the tips of the upper clamp 1 and the lower clamp 3 is not less than 40mm.

[0071] The width of the magnetic plate boss 4a is 2mm-4mm larger than the width of the clamp.

[0072] Hinged assembly 5 is a damping component.

[0073] The method for using the positioning tool includes the following steps: S1. Using a right-angle ruler, precisely extend the reference line on the front side of the steel plate 11 to be marked, which needs to transition to the back side, to both sides of the steel plate 11 to be marked, to form the front reference line 10, and make short scribing marks on the edges. S2. Hold the positioning tool by the handle and straddle the edge of the steel plate 11 to be marked, with the upper jaw 1 on the front of the steel plate 11 and the lower jaw 3 on the back of the steel plate 11. At this time, the lower clamp 3 and the lower handle 6a of the clamp are on the same plane due to the limitation of the bushing stop 5d, and the lower clamp 3 is completely attached to the back of the steel plate 11 to be scribed. At this time, the bushing stop 5d between the upper clamp 1 and the handle 6 on the clamp is not in action. The two are not in the same plane. The upper clamp 1 is also completely attached to the front of the steel plate 11 to be scribed, so that the positioning tool is initially fixed on the steel plate 11 to be scribed by the elastic force of the elastic element 8. S3. Precise alignment of the front side, which includes the following sub-steps: S31. Look vertically upwards from the front of the steel plate 11 to be marked, towards the positioning gap 2 of the clamping jaw 1. S32. Fine-tune the position of the positioning tool so that the positioning gap 2 completely coincides with the front baseline 10 mark; S33. Attach the detachable magnetic sheet 4 to the front end of the upper clamp 1 and the lower clamp 3 so that it is attracted to the steel plate 11 to be scribed. S4. Draw lines on the reverse side, which includes the following sub-steps: S41. Keep the positioning tool fixed and move the operating position to the back of the steel plate 11 to be marked. S42. Remove the pen 9 from the positioning tool and place it into the positioning gap 2 of the lower clamp 3 to draw lines. The length of the short line segment drawn is equal to the length of the gap. S5. Repeat the operation and connection, which includes the following sub-steps: S51. Squeeze the upper handle 6 and the lower handle 6a of the clamp to release the positioning tool. At this time, under the action of gravity, the upper clamp 1 causes the bushing baffle 5d to act on the lower side of the upper handle 6 of the clamp, so that the upper clamp 1 and the upper handle 6 of the clamp are on the same plane, so that the positioning tool leaves the current working position and moves to the other edge of the steel plate 11 to be marked. S52. Repeat steps S3 and S4 to obtain another scribing line on the reverse edge of the steel plate 11 to be scribed. S53. Using a ruler, connect the two lines on the reverse edge to obtain a complete reverse baseline that is perfectly parallel to the front baseline in space and corresponds precisely in position. Example 2

[0074] A positioning tool for scribing lines on the reverse side of a steel plate, characterized in that: the tool includes a chuck assembly, a hinge assembly 5, a jaw assembly, and a fixing assembly; the fixing assembly is used to fix the jaw assembly to the steel plate. The clamp assembly uses a spring element 8 to connect the upper handle 6 and the lower handle 6a of the clamp; The clamping assembly includes an upper clamping mouth 1 and a lower clamping mouth 3. The upper clamping mouth 1 is used to act on the front side of the steel plate, and the lower clamping mouth 3 is used to act on the back side of the steel plate. Both the upper clamping mouth 1 and the lower clamping mouth 3 are provided with positioning gaps 2. The positioning gap on the upper clamping mouth is used to align with the front reference line. The positioning gap on the lower clamping mouth is used to provide a scribing reference for the back side of the steel plate. The upper clamp 1 and the upper handle 6 of the clamp are connected by a hinge assembly 5, and the lower clamp 3 and the lower handle 6a of the clamp adopt an integrated structure. In the hinge assembly 5, the handle bushing 5b is located at the end of the handle 6 on the clamp, and the jaw plate bushing 5c ​​is located at the end of the upper jaw 1. The handle bushing 5b and the jaw plate bushing 5c ​​are arranged alternately and connected in series by a cylindrical pin 5a, so that the handle 6 on the clamp and the upper jaw 1 are hinged. A bushing baffle 5d is provided at the bottom of the jaw plate bushing 5c. The bushing baffle 5d extends and acts on the lower side of the clamp handle to limit the swing of the jaw plate. The fixing component adopts a detachable magnetic sheet 4, and the magnetic sheet boss 4a connects the magnetic sheet plates 4b on both sides; the magnetic sheet boss 4a is fastened in the width direction of the clamping assembly, and the upper clamping mouth 1 and the lower clamping mouth 3 are fixed to the front and back of the steel plate respectively by magnetic force.

[0075] The method for using the positioning tool includes the following steps: S1. Using a right-angle ruler, precisely extend the reference line on the front side of the steel plate 11 to be marked, which needs to transition to the back side, to both sides of the steel plate 11 to be marked, to form the front reference line 10, and make short scribing marks on the edges. S2. Hold the positioning tool by the handle and straddle the edge of the steel plate 11 to be marked, with the upper jaw 1 on the front of the steel plate 11 and the lower jaw 3 on the back of the steel plate 11. At this time, when the clamping mouth 3 and the lower handle 6a of the clamp adopt an integrated structure, the two are on the same plane, and the lower clamping mouth 3 is completely attached to the back of the steel plate 11 to be scribed. At this time, the bushing stop 5d between the upper clamp 1 and the handle 6 on the clamp is not in action. The two are not in the same plane. The upper clamp 1 is also completely attached to the front of the steel plate 11 to be scribed, so that the positioning tool is initially fixed on the steel plate 11 to be scribed by the elastic force of the elastic element 8. S3. Precise alignment of the front side, which includes the following sub-steps: S31. Look vertically upwards from the front of the steel plate 11 to be marked, towards the positioning gap 2 of the clamping jaw 1. S32. Fine-tune the position of the positioning tool so that the positioning gap 2 completely coincides with the front baseline 10 mark; S33. Attach the detachable magnetic sheet 4 to the front end of the upper clamp 1 and the lower clamp 3 so that it is attracted to the steel plate 11 to be scribed. S4. Draw lines on the reverse side, which includes the following sub-steps: S41. Keep the positioning tool fixed and move the operating position to the back of the steel plate 11 to be marked. S42. Remove the pen 9 from the positioning tool and place it into the positioning gap 2 of the lower clamp 3 to draw lines. The length of the short line segment drawn is equal to the length of the gap. S5. Repeat the operation and connection, which includes the following sub-steps: S51. Squeeze the upper handle 6 and the lower handle 6a of the clamp to release the positioning tool. At this time, under the action of gravity, the upper clamp 1 causes the bushing baffle 5d to act on the lower side of the upper handle 6 of the clamp, so that the upper clamp 1 and the upper handle 6 of the clamp are on the same plane, so that the positioning tool leaves the current working position and moves to the other edge of the steel plate 11 to be marked. S52. Repeat steps S3 and S4 to obtain another scribing line on the reverse edge of the steel plate 11 to be scribed. S53. Using a ruler, connect the two lines on the reverse edge to obtain a complete reverse baseline that is perfectly parallel to the front baseline in space and corresponds precisely in position.

[0076] 1. The method proposed in this case, which involves setting elongated through holes that are vertically aligned with each other in the upper and lower clamps, as a front alignment reference and a back marking guide reference, is not currently used in construction technology.

[0077] 2. This case is the first in the industry to use a high-precision hinge to adjust the upper and lower jaws to fit perfectly with the steel plate.

[0078] 3. This case utilizes a detachable magnetic sheet to fix the marking clip and prevent it from shifting, which has strong practical value.

[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A positioning tool for scribing lines on the reverse side of a steel plate, characterized in that: The tool includes a chuck assembly, a hinge assembly (5), a jaw assembly, and a fixing assembly; the fixing assembly is used to fix the jaw assembly to the steel plate; The clamp assembly uses an elastic element (8) to connect the upper handle (6) and the lower handle (6a) of the clamp. The clamping assembly includes an upper clamping mouth (1) and a lower clamping mouth (3). The upper clamping mouth (1) is used to act on the front side of the steel plate, and the lower clamping mouth (3) is used to act on the back side of the steel plate. Positioning gaps (2) are provided on both the upper clamp (1) and the lower clamp (3). The positioning gap on the upper clamp is used to align with the front reference line; the positioning gap on the lower clamp is used to provide a scribing reference for the reverse side of the steel plate. The upper clamp (1) and the upper handle (6) of the clamp are connected by a hinge assembly (5), and the lower clamp (3) and the lower handle (6a) of the clamp are connected by a hinge assembly (5) or adopt an integrated structure. In the hinge assembly (5), the handle bushing (5b) is located at the end of the clamp handle, and the jaw plate bushing (5c) is located at the end of the jaw plate. The handle bushing (5b) and the jaw plate bushing (5c) are arranged alternately and connected by a cylindrical pin (5a) to hinge the clamp handle and the jaw plate. The bottom of the jaw plate bushing (5c) is provided with a bushing baffle (5d), which extends and acts on the lower side of the clamp handle to limit the swing of the jaw plate. When the lower jaw (3) and the lower handle (6a) of the clamp are connected by a hinge assembly (5), the clamp handle includes an upper handle (6) and a lower handle (6a), and the jaw plate includes an upper jaw (1) and a lower jaw (3). When the clamping mouth (3) and the lower handle (6a) of the clamp are integrated, the clamping handle is the upper handle (6) of the clamp and the clamping mouth plate is the upper clamping mouth (1). The fixing component adopts a detachable magnetic sheet (4), and the magnetic sheet boss (4a) connects the magnetic sheet plates (4b) on both sides. The magnetic sheet boss (4a) is fastened in the width direction of the clamping assembly, and the upper clamping mouth (1) and the lower clamping mouth (3) are fixed to the front and back of the steel plate respectively by magnetic force.

2. The positioning tool for scribing lines on the reverse side of a steel plate according to claim 1, characterized in that: The width of the positioning gap (2) is 0.8mm ± 0.05mm.

3. A positioning tool for scribing lines on the reverse side of a steel plate according to claim 1, characterized in that: The upper handle (6) and lower handle (6a) of the clamp are respectively provided with anti-slip texture (6b), and the contact surfaces of the upper clamp (1) and lower clamp (3) with the steel plate (11) to be marked are anti-slip surfaces.

4. A positioning tool for scribing lines on the reverse side of a steel plate according to claim 1, characterized in that: The upper handle (6) and lower handle (6a) of the clamp are respectively marked with a mark (7).

5. A positioning tool for scribing lines on the reverse side of a steel plate according to claim 1, characterized in that: The maximum separation distance between the top of the upper clamp (1) and the lower clamp (3) is not less than 40 mm.

6. A positioning tool for scribing lines on the reverse side of a steel plate according to claim 1, characterized in that: The width of the magnetic protrusion (4a) is 2mm-4mm larger than the width of the clamp.

7. A positioning tool for scribing lines on the reverse side of a steel plate according to claim 1, characterized in that: The hinge assembly (5) is a damping component.

8. A method for scribing lines using a positioning tool according to any one of claims 1-7, characterized in that, Includes the following steps: S1. Using a right-angle ruler, extend the reference line on the front side of the steel plate (11) that needs to transition to the back side precisely to the two sides of the steel plate (11) to become the front reference line (10), and make short scribing marks on the edge. S2. Hold the positioning tool by the handle and straddle the edge of the steel plate (11) to be marked. The upper clamp (1) is on the front of the steel plate (11) to be marked, and the lower clamp (3) is on the back of the steel plate (11). At this time, when the clamp (3) and the lower handle (6a) of the clamp adopt an integrated structure, the two are on the same plane; or when the lower clamp (3) and the lower handle (6a) of the clamp are connected by a hinge assembly (5), the lower clamp (3) and the lower handle (6a) of the clamp are on the same plane due to the limitation of the bushing stop (5d), and the lower clamp (3) is completely attached to the back of the steel plate (11) to be scribed; The bushing stop (5d) between the upper clamp (1) and the handle (6) of the clamp does not function at this time. The two are not in the same plane. The upper clamp (1) is also completely attached to the front of the steel plate (11) to be scribed, so that the positioning tool is initially fixed on the steel plate (11) to be scribed by the elastic force of the elastic element (8). S3. Precise alignment of the front side, which includes the following sub-steps: S31. Look vertically from the front of the steel plate (11) to be marked, at the positioning gap (2) of the clamp (1). S32. Fine-tune the position of the positioning tool so that the positioning gap (2) completely coincides with the front reference line (10) mark; S33. Attach the detachable magnetic sheet (4) to the front end of the upper clamp (1) and the lower clamp (3) so that it is attracted to the steel plate (11) to be scribed. S4. Draw lines on the reverse side, which includes the following sub-steps: S41. Keep the positioning tool fixed and move the operation position to the back of the steel plate (11) to be marked. S42. Remove the pen (9) from the positioning tool and place it into the positioning gap (2) of the lower clamp (3) to draw lines. The length of the short line segment drawn is equal to the length of the gap. S5. Repeat the operation and connection, which includes the following sub-steps: S51. Pinch the upper handle (6) and lower handle (6a) of the clamp to release the positioning tool. At this time, under the action of gravity, the upper jaw (1) causes the bushing baffle (5d) to act on the lower side of the upper handle (6) of the clamp, so that the upper jaw (1) and the upper handle (6) of the clamp are on the same plane, so that the positioning tool leaves the current working position and moves to the other edge of the steel plate (11) to be marked. S52. Repeat steps S3 and S4 to obtain another scribing line on the reverse edge of the steel plate (11) to be scribed; S53. Using a ruler, connect the two lines on the reverse edge to obtain a complete reverse baseline that is perfectly parallel to the front baseline in space and corresponds precisely in position.

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