A computerized steel tape error detection device

Abstract

A computerized steel tape measure indication error detection device comprises a steel tape measure clamp and an electric rotary table assembly fixedly mounted on the front plate of the device housing at the same horizontal line. The electric rotary table assembly includes an electric rotary table and a winding wheel mechanism. The rotating shaft of the winding wheel mechanism extends out of the front plate of the housing, with a shaft groove at one end and the other end fixedly connected to the electric rotary table. The top of the housing has an operation panel and a display screen. The housing contains electrical components, including a controller, a lower-level computer, and a higher-level computer. A camera assembly and a grating ruler are also fixedly connected to the front of the front plate of the housing. The hook of the steel tape measure under test is inserted into the shaft groove of the electric rotary table assembly. The rotation of the electric rotary table pulls the steel tape measure horizontally. The display screen shows the image from the camera and the indication error calculated by the higher-level computer in real time. This utility model of an automatic steel tape measure detection device adopts a direct measurement method, occupies little space, and features fast, accurate, and automatic detection.

Description

Technical Field

[0001] This utility model belongs to the technical field of steel tape measure indication error calibration, specifically referring to a computerized steel tape measure indication error detection device. Background Technology

[0002] As a basic measuring tool in industrial manufacturing, construction and other fields, the accuracy of steel tape measures directly affects product quality and engineering reliability.

[0003] According to the JJG 4-2015 Steel Measuring Tape Verification Procedure, the existing testing method for steel measuring tapes mainly involves comparative measurement using standard steel measuring tapes. However, steel measuring tapes are prone to measurement deviations during production and use due to material deformation, scale marking errors, and environmental factors, especially for large-size (over 5m) steel measuring tapes where the cumulative error is more significant.

[0004] Currently, mainstream steel tape measure indication error calibration technologies still face the following technical bottlenecks: First, the adaptability of the calibration equipment is insufficient. Traditional calibration equipment often uses a 5m long calibration table, requiring a large laboratory space. Furthermore, the standard tape measure and the tape measure under test must be placed side-by-side and manually aligned with weights, making it difficult to adapt to different specifications (e.g., 0–30000mm to 0–100000mm) of steel tape measures, necessitating segmented measurements. In addition, insufficient rigidity of the support structure easily leads to tape measure bending or shifting, affecting calibration accuracy. Although some improved devices achieve length adjustment through support slides and zeroing components, they still rely on manual operation, resulting in low efficiency. Second, errors are introduced by manual operation. Existing calibration procedures require visually comparing the scales of the standard tape measure and the tape measure under test, recording errors point by point. For example, conventional methods require aligning the zero points of the standard tape measure and the tape measure under test, then manually moving the reading microscope at multiple comparison points (e.g., 1m, 2m, 5m, etc.). Repetitive operations easily lead to visual fatigue and positioning deviations, with cumulative errors reaching ±1.5mm (domestic standard) or even higher. Furthermore, tension control relies on manually suspended weights; if not operated at the standard tension (e.g., 49N), additional errors will occur due to elastic deformation. Thirdly, environmental factors are poorly controlled; the thermal expansion coefficient of the steel measuring tape (α=1.25×10⁻⁶) is also a concern. -5 The steel tape measure ( / ℃) is sensitive to temperature, but most calibration environments lack temperature control measures and rely solely on room temperature (20℃±8℃), resulting in ineffective compensation for temperature drift errors. Furthermore, insufficient levelness of the steel tape measure or uneven support surfaces can introduce geometric errors; for example, a height difference of 0.4m between the two ends of a 30m tape measure can lead to an error of 2.6mm. Fourth, the steel tape measure strip is made of stainless steel, posing a risk of hand injury during manual operation.

[0005] Chinese invention patent CN117928331B discloses a calibration device for steel tape measures, including a testing platform. A steel tape measure body is placed on the surface of the testing platform, and a tape measure strip is housed inside the steel tape measure body. A positioning mechanism that cooperates with the steel tape measure body is provided on the surface of the testing platform. The positioning mechanism includes a clamping component and a telescopic component. A protective mechanism that cooperates with the tape measure strip is provided on the surface of the testing platform. The protective mechanism includes a pressing column, a support component, and a pressing component. This utility model provides auxiliary pressing and positioning functions. By setting the support component and the pressing component to cooperate with each other, the position of the pressing column can be automatically adjusted while the tape measure strip is telescopically extending and retracting inside the steel tape measure body, thereby pressing and protecting the tape measure strip, effectively improving the stability of the tape measure strip during testing, and solving the problem of the tape measure strip easily falling off and automatically rewinding back into the steel tape measure body in existing calibration devices, posing a risk of cutting the palm. However, it still adopts the existing JJG 4-2015 steel tape measure calibration procedure testing method, which still requires a large space for the testing platform, and does not provide an intelligent measurement scheme for the steel tape measure testing.

[0006] Chinese invention patent CN116972709B discloses a method and system for analyzing the calibration error of a steel tape measure. This method offers advantages such as high automation, precise calibration, and high efficiency. Two embodiments are provided. The overall approach is as follows: Zero-point calibration of the steel tape measure calibration device; when the steel tape measure reaches a predetermined position, a clamping unit grasps the steel tape measure and engages a measuring block with it. A pressure block fixes the measuring block and the measuring end of the steel tape measure, while the clamping unit secures the tape measure; the measuring block is controlled to slide, and the sliding distance is recorded and used as a standard distance; an image set is established by acquiring images of the zero-point line and the scale lines of the steel tape measure using a CCD sensor; a processing network is configured based on the acquisition parameters of the CCD sensor, and the network performs recognition processing on the verification image set to generate a scale recognition result; error analysis is performed based on the standard distance and the scale recognition result to generate an error calibration result. As can be seen from the literature, the relative sliding distance of the measuring block is used as the standard displacement, and CCD image acquisition is used to calculate the error of the steel tape measure. When the steel tape measure reaches the position, the clamping unit is activated and fixes the steel tape measure to ensure that the measurement will not move or shake during the measurement process. Therefore, this scheme, which uses sliding as the standard distance, requires a large motion platform and a large space for the calibration table, at least 5m, to meet the testing needs of most steel tape measures. However, it does not explain how to test large-range steel tape measures, such as 50m steel tape measures, and cannot achieve automatic testing of large-range steel tape measures.

[0007] Chinese utility model patent CN116164608B discloses a semi-automatic high-efficiency calibration device for steel tape measures. It includes a calibration table with positioning blocks on the table, each serving as a clamping device. A fixing device is located on one side of the clamping device, and a measuring structure is located at the other end of the fixing device. The steel tape measure is measured using this measuring structure. A limit device is located on the other side of the measuring structure on the calibration table. This utility model places the steel tape measure between the positioning blocks. When the soft bladder is squeezed, a first slider inside the guide block is expelled, causing the limit block connected to the first slider to move, thus achieving the effect of positioning the zero point. At this time, the limit groove continues to advance, thereby automatically recording the error value. By fixing the measured distance, it achieves segmented calibration, increasing the calibration efficiency of steel tape measure calibration to a certain extent. However, this solution still uses a standard ruler for manual comparison measurement, requires a large space for the calibration table, and has a low degree of automation.

[0008] Similarly, the solutions disclosed in Chinese utility model patents CN222718812U, CN222579103U, CN221781396U, CN221484376U, and CN221425521U all use a large horizontal calibration platform to calibrate steel tape measures, which occupy a large space.

[0009] Therefore, there is an urgent need for an automatic detection device for steel tape measure indication error that occupies little space and adopts a direct measurement method, in order to achieve rapid, accurate and automatic detection of steel tape measures. Utility Model Content

[0010] The technical problem to be solved by this utility model is to provide a small-sized, fast, accurate, efficient, and computer-controlled device for detecting the error of steel tape measure readings.

[0011] This utility model is implemented as follows:

[0012] A computerized steel tape measure indication error detection device includes: a housing, on which a steel tape measure clamp and an electric rotary table assembly are fixedly installed on the same horizontal line as the front plate of the housing; the electric rotary table assembly includes: an electric rotary table and a winding wheel mechanism connected thereto.

[0013] The electric rotary table is installed inside the housing, and the rotating shaft of the winding wheel mechanism extends out of the front plate of the housing. A shaft groove is opened at one end, and the other end is fixedly connected to the electric rotary table.

[0014] The top of the casing has an operation panel, and the operation panel has a display screen;

[0015] The housing contains electrical components, which include: a controller, a lower-level computer, and a higher-level computer.

[0016] A sheet metal mounting base is fixedly connected to the front of the front panel of the housing. A single-axis module and a grating ruler are provided on the sheet metal mounting base. The reading head on the grating ruler is fixedly connected to the side of the single-axis module through a mounting plate. A camera assembly is fixedly connected to the top of the single-axis module. The grating ruler reads the position information of the single-axis module in real time and transmits it to the lower-level machine.

[0017] The camera assembly includes: a support, a column, a connecting base, a connecting plate, a camera, a fixing plate, and an LED light; the support is fixedly connected to the top of the single-axis module, and the column is fixedly connected to the top of the support; the camera is fixedly connected to the connecting base on the column via the connecting plate, and the LED light is also provided below the camera. The side of the LED light is connected to the connecting base via the fixing bracket. The camera is located above the steel tape measure being inspected, captures images of the scale of the steel tape measure being inspected, and uploads them to the lower-level machine;

[0018] The single-axis module, the grating ruler, and the electric rotary table are all connected to the controller;

[0019] Two rolling lifting wheel assemblies are provided at an interval between the steel tape measure clamp and the electric rotary table assembly, and are installed inside the machine housing;

[0020] The two rolling lifting wheel assemblies are arranged symmetrically;

[0021] Each of the rolling lifting roller assemblies has two rollers, which are respectively located above and below the steel tape measure being inspected, to realize the rotational movement and lifting and pressing action of the two rollers, for stabilizing and flattening the steel tape measure being inspected.

[0022] The steel tape measure clamp includes: an L-shaped fixed bracket, two cylindrical seats, and a U-shaped support rod; the vertical end of the L-shaped fixed bracket is fixed to the front plate of the machine housing, and the two cylindrical seats are located at the horizontal end of the L-shaped fixed bracket near the vertical end; the two ends of the U-shaped support rod are bent downward and inserted into the two cylindrical seats and fixedly connected by springs.

[0023] The steel tape measure to be inspected is fixedly installed on the steel tape measure clamp. The hook of the steel tape measure to be inspected is inserted into the shaft groove of the electric rotary table assembly. The steel tape measure is moved horizontally by the rotation of the electric rotary table. The display screen on the operation panel of the machine housing displays the image captured by the camera in real time and the steel tape measure indication error result calculated by the host computer.

[0024] Furthermore, each of the rolling lifting wheel assemblies includes: a motor, a transmission mechanism, a first rotating wheel, a second rotating wheel, a first transmission shaft, a second transmission shaft, a third transmission shaft, a gearbox, and the two rollers;

[0025] The drive shaft of the motor drives the first wheel and the second wheel to rotate in the same direction through the transmission mechanism;

[0026] One end of the first drive shaft is connected to the center of the first rotating wheel, and the other end is connected to the lower roller of the two rollers;

[0027] One end of the second drive shaft is connected to the center of the second rotating wheel, and the other end passes through the gearbox and extends out of the gearbox; a gear transmission mechanism is provided inside the gearbox, and inside the gearbox, the second drive shaft drives the third drive shaft to rotate in the opposite direction through the gear transmission mechanism, and one end of the third drive shaft extends out of the gearbox and connects to the upper roller of the two rollers;

[0028] A lifting mechanism is fixedly installed above the gearbox. The lifting mechanism includes: a lifting top plate, a lifting pressure plate, and a knob shaft.

[0029] The top plate is installed on the gearbox in a sloping manner. The top of the top plate abuts against the top of the "7"-shaped lifting pressure plate. The middle part of the lifting pressure plate is fixedly connected to the extension end of the knob shaft. The bottom of the lifting pressure plate abuts against the middle part of the top plate. Rotating the knob on the knob shaft causes the lifting pressure plate to rotate, thereby pushing the top plate and raising or lowering the upper roller.

[0030] Furthermore, the lifting plate in each of the lifting wheel mechanisms also abuts against a fine-tuning component;

[0031] The two fine-tuning components are symmetrically arranged;

[0032] Each of the aforementioned fine-tuning components includes: a rotary rod, a knurled wheel, a threaded support, a handwheel, and a smooth support;

[0033] One end of the rotating rod is fixedly connected to the straight knurled wheel; the threaded support, the handwheel, and the smooth support are sequentially mounted on the rotating rod;

[0034] The threaded support and the optical support are fixedly mounted on the front plate of the housing.

[0035] A spring plate is provided at the top of the optical support, and a steel ball is provided between the spring plate and the straight knurling wheel;

[0036] The other end of the rotary rod abuts against the lifting plate. By rotating the handwheel, the rotary rod presses against the lifting plate to finely adjust the distance between the two rollers.

[0037] The advantages of this utility model are:

[0038] 1. The computer-based structure makes the entire testing device highly compact, flexible, and requires little laboratory space.

[0039] 2. Direct measurement is achieved through camera technology, changing the traditional comparative measurement method of steel tape measure and reducing the error introduced by tensile deformation in the traditional steel tape measure inspection process;

[0040] 3. Two pairs of upper and lower rollers with adjustable gap are used to press down on the steel tape measure under inspection, which facilitates camera data recognition and reduces the error introduced by the bending deformation of the steel tape measure itself, thereby improving the detection accuracy. At the same time, the two pairs of rollers can realize the up and down lifting function, which facilitates the loading and unloading of the steel tape measure under inspection.

[0041] 4. An electric rotary table drives the winding wheel mechanism to rotate, realizing the unwinding and rewinding of the inspected steel coil. This provides the initial zero position of the inspected steel tape measure and also winds up the measured body after inspection, further protecting the steel tape measure and preventing it from cutting the palm.

[0042] 5. The left and right movement of a single-axis module is adopted to realize the identification of the camera's zero position and the detection of the indication error, which improves the utilization efficiency of a single camera and makes the structure more compact.

[0043] 6. A dedicated steel tape measure clamp is used to enable quick loading and unloading of the steel tape measure being inspected; Attached Figure Description

[0044] The present invention will now be further described with reference to the accompanying drawings and embodiments.

[0045] Figure 1 This is a schematic diagram of the external structure of the detection device of this utility model in use.

[0046] Figure 2 This is a front perspective view of the front panel of the housing in the testing device of this utility model (with the steel tape measure clamp removed).

[0047] Figure 3 This is a schematic diagram of the back of the front panel of the housing in the detection device of this utility model.

[0048] Figure 4 This is a schematic diagram of the first rolling lifting wheel assembly in the detection device of this utility model.

[0049] Figure 5 This is a schematic diagram of the second rolling lifting wheel assembly in the detection device of this utility model.

[0050] Figure 6 This is a schematic diagram of the first fine-tuning component in the detection device of this utility model.

[0051] Figure 7This is a schematic diagram of the structure of the second fine-tuning component in the detection device of this utility model.

[0052] Figure 8 This is a schematic diagram of the winding wheel mechanism in the detection device of this utility model.

[0053] Figure 9 This is a structural schematic diagram of the steel tape measure clamp in the testing device of this utility model.

[0054] Figure 10 This is a schematic diagram showing the positional relationship between the single-axis module, the grating ruler, and the mounting base in the detection device of this utility model.

[0055] Figure 11 This is a schematic diagram of the camera component structure in the detection device of this utility model.

[0056] Figure 12 This is a schematic diagram of the operation panel and display screen in the detection device of this utility model.

[0057] Figure 13 This is a schematic diagram of the zero-point image acquisition of the steel tape measure in the detection and measuring device of this utility model.

[0058] Figure 14 This is a schematic diagram of the image acquisition of the steel tape measure engraving on the display screen of the detection device of this utility model.

[0059] Figure 15 This is a block diagram of the system control principle in the detection device of this utility model. Detailed Implementation

[0060] Please see Figures 1 to 15 As shown, a computer-controlled steel tape measure indication error detection device includes: a housing 4, a steel tape measure clamp 11 and an electric rotary table assembly 3 fixedly installed on the same horizontal line of the front plate 41 of the housing 4.

[0061] The electric rotary table assembly 3 includes: an electric rotary table 31 (model E-RMPG40) and a winding wheel mechanism 32 connected thereto; the electric rotary table 31 is installed in the rear upright plate 42 inside the housing 4, the rotating shaft 321 of the winding wheel mechanism 32 extends out of the front plate 41 of the housing 4, and its end is provided with a shaft groove 3211, and the other end is fixedly connected to the electric rotary table 31; the winding wheel mechanism 32 includes a rotating shaft 321, a bearing 322 for easy installation and fixing, a flange 323, and a limiting shaft 324 for limiting the bearing 322.

[0062] The top of the casing 4 has an operation panel 7, which has a display screen 71;

[0063] The internal structure of the housing 4 contains electrical components, including: a controller, a lower-level computer, and a higher-level computer;

[0064] A sheet metal mounting base 81 is also fixedly connected to the front of the front panel 41 of the housing 4. A single-axis module 82 and a grating ruler 86 are provided on the sheet metal mounting base 81. The reading head 85 on the grating ruler 86 is fixedly connected to the side of the single-axis module 82 through a mounting plate 84. A camera assembly 9 is also fixedly connected to the top of the single-axis module 82 through a rotating mounting plate 83. The grating ruler on the grating ruler 86 reads the position information of the single-axis module 82 in real time and transmits it to the lower computer.

[0065] The camera assembly 9 includes: a support 91, a column 92, a connecting seat 93, a camera 94, a connecting plate 95, an LED light 96, and a fixing frame 97. The support 91 is fixedly connected to the top of the single-axis module 82, the column 92 is fixedly connected to the top of the support 91, the camera 94 is fixedly connected to the connecting seat 93 on the column 92 through the connecting plate 95, and an LED light 96 is also provided below the camera 94. The side of the LED light 96 is connected to the connecting seat 93 through a fixing frame 97. The camera 94 is located above the steel tape measure 1 under inspection, and captures images of the scale of the steel tape measure 1 under inspection and uploads them to the lower computer.

[0066] The single-axis module 82, the grating ruler 86, and the electric rotary table 31 are all connected to the controller;

[0067] The steel tape measure 1 to be inspected is fixedly installed on the steel tape measure clamp 11. The hook of the steel tape measure 1 to be inspected is inserted into the shaft groove 3211 of the electric rotary table assembly 3. The steel tape measure 1 to be inspected is moved horizontally by the rotation of the electric rotary table 31. The display screen 71 on the operation panel 7 of the machine housing 4 displays the image captured by the camera 94 in real time and the steel tape measure indication error result calculated by the host computer.

[0068] The housing 4 has four feet 12 on its lower part, and the sheet metal mounting base 81 also has a foot 13 on its lower part.

[0069] Two rolling lifting wheel assemblies (first rolling lifting wheel assembly 51 and second rolling lifting wheel assembly 52) are provided at an interval between the steel tape measure clamp 11 and the electric rotary table assembly 3, and are installed inside the machine housing 4;

[0070] The first rolling lifting wheel assembly 51 and the second rolling lifting wheel assembly 52 are symmetrically arranged and have the same structure;

[0071] The first rolling lifting wheel assembly 51 has two upper and lower rollers 5101 and 5102, and the second rolling lifting wheel assembly 52 has two upper and lower rollers 5201 and 5202, which are respectively located above and below the steel tape measure 1 to realize the rotational movement and lifting and pressing action of the rollers 5101, 5102, 5201 and 5202, for stabilizing and flattening the steel tape measure 1.

[0072] The following describes the specific structure of the first rolling lifting wheel assembly 51 as an example, including: motor 5103, transmission mechanism 5104 (belt drive or gear drive, this embodiment uses a belt pulley, but in practice it can also be implemented using gear drive), first rotating wheel 5105, second rotating wheel 5106, first transmission shaft 5107, second transmission shaft 5108, third transmission shaft 5109, gearbox 5110, and two rollers 5101 and 5102.

[0073] The motor 5103 is mounted on the rear upright plate 42 inside the housing 4 via two support columns 51031. The drive shaft wheel 51032 of the motor 5103 drives the first rotating wheel 5105 and the second rotating wheel 5106 to rotate in the same direction via the transmission mechanism 5104.

[0074] One end of the first drive shaft 5107 is connected to the center of the first rotating wheel 5105, and the other end is connected to the lower roller 5102 of the two rollers;

[0075] One end of the second drive shaft 5108 is connected to the center of the second rotating wheel 5106, and the other end passes through the gearbox 5110 and extends out of the gearbox 5110.

[0076] A gear transmission mechanism is provided inside the gearbox 5110. Inside the gearbox 5110, the second transmission shaft 5108 drives the third transmission shaft 5109 to rotate in the opposite direction through the gear transmission mechanism. One end of the third transmission shaft 5109 extends out of the gearbox 5110 and connects to the upper roller 5101 of the two rollers.

[0077] A lifting mechanism is fixedly installed on the top of the gearbox 5110. The lifting mechanism includes a top plate 5111, a pressure plate 5112, and a knob shaft 5113. The top plate 5111 is installed on the gearbox 5110 in a sloping manner. The top of the top plate 5111 abuts against the top of the "7"-shaped pressure plate 5112. The middle part of the pressure plate 5112 is fixedly connected to the extension end of the knob shaft 5113, and the bottom of the pressure plate 5112 abuts against the middle part of the top plate 5111. Rotating the knob 5114 on the knob shaft 5113 causes the pressure plate 5112 to rotate, thereby pushing the top plate 5111, which in turn raises or lowers the upper roller 5101. The top plate 5111 in the lifting mechanism also abuts against a fine-tuning component 61.

[0078] The two fine-tuning components 61 and 62 are symmetrically arranged and have the same structure;

[0079] The following description uses the fine-tuning component 61 as an example to illustrate its specific structure. The fine-tuning component 61 includes: a rotating rod 611, a straight knurled wheel 612, a threaded support 613, a handwheel 614, and a smooth support 615; one end of the rotating rod 611 is fixedly connected to the straight knurled wheel 612; the threaded support 613, the handwheel 614, and the smooth support 615 are sequentially mounted on the rotating rod 611; the sides of the threaded support 613 and the smooth support 615 are fixedly mounted on the front plate 41 of the housing 4.

[0080] A spring plate 616 is provided on the top of the light support 615, and a steel ball 617 is provided between the spring plate 616 and the straight knurling wheel 612; the other end of the rotating rod 611 abuts against the lifting plate 5111, and by rotating the handwheel 614, the rotating rod 611 presses against the lifting plate 5111 to finely adjust the distance between the two rollers 5101 and 5102.

[0081] The steel tape measure clamp 11 includes: an L-shaped fixing bracket 111, two cylindrical seats 112, and a U-shaped support rod 113. The vertical end of the L-shaped fixing bracket 111 is fixed to the front plate 41 of the housing 4. The two cylindrical seats 112 are located at the horizontal end of the L-shaped fixing bracket 111 near the vertical end. The two ends of the U-shaped support rod 113 are bent downwards and inserted into the two cylindrical seats 112, and are fixedly connected by springs. When it is necessary to fix the steel tape measure 1, the U-shaped support rod 113 is pulled upwards a certain distance, the steel tape measure 1 is placed on the horizontal end of the L-shaped fixing bracket 111, and the U-shaped support rod 113 is released. Under the restoring force of the spring, the U-shaped support rod 113 firmly clamps the top of the steel tape measure 1.

[0082] The electric rotary table 31, the two rolling lifting wheel assemblies 51 and 52, and the single-axis module 82 are all driven by a designed control system (the system control principle block diagram is shown below). Figure 15 As shown, it can achieve precise positioning to each target detection point. The operation control on the control panel 7 of the control housing starts the electric rotary table 31 and the two rolling lifting wheel assemblies 51 and 52 to drive and carry out the detection process.

[0083] The specific testing method includes the following steps:

[0084] Step 1: Install the steel measuring tape 1 to be inspected onto the steel measuring tape clamp 11;

[0085] Step 2: Pull out the hook of the steel measuring tape 1 to be inspected and insert the hook into the shaft groove 3211 of the electric rotary table assembly 3;

[0086] Step 3: Manually operate the single-axis module 82 on the operation panel 7 to move the camera 94 above the graduation line of the steel tape measure 1 under inspection, stop at the "inspection position", adjust the up and down and rotation position of the connecting seat 93 to make the image of the camera 94 clear, and lock the connecting seat 93.

[0087] Then, manually operate the single-axis module 82 on the operation panel 7 to move the camera 94 to the "zero position" position, operate the "starting scale line" button on the display screen 71 to make the starting scale line L0 coincide with the left side of the shaft groove 3211 of the rotating shaft, the grating ruler 86 connected to the camera 94 is zeroed, and the electric rotary table 31 is zeroed at the same time.

[0088] Step 4: Move the camera to the "detection position". The camera 94 moves along the steel measuring tape 1 from the "zero position" to the "detection position" and stops. At this time, the reading displayed on the display screen 71 by the grating ruler 86 is Lg, which represents the fixed distance value between the "zero position" and the "detection position".

[0089] Step 5: Begin testing at the first target detection point, 1000mm scribed line:

[0090] Calculate the horizontal target distance Lxˊ1 that the electric rotary table 31 needs to rotate from the "zero position" to the "detection position" of the first target detection point of the steel tape measure 1 under inspection. Lxˊ1 = Lb1 - Lg, where Lb1 is the nominal value of the first target detection point, i.e., 1000mm; (assuming the Lg reading is 250.002mm, then Lx′1 = Lb1 - Lg = 1000 - 250.002 = 749.998mm). After the calculation is completed, the motor of the electric rotary table 31 reaches the horizontal target distance Lxˊ1 through closed-loop control. At this time, the actual horizontal distance rotated is Lx1, and the actual distance of the standard scale line Ls displayed on the display screen 71 is Ls = Lg + Lx1.

[0091] Step Six: Move the left and right graduations on the display screen 71 so that the left graduation L2 and the right graduation L1 coincide with the left and right edges of the graduations of the first target measurement point of the actual steel tape measure 1, respectively, to generate a middle graduation Lm of the first target measurement point of the steel tape measure. Using the distance measurement function of the camera in the same field of view, measure the distance between Lm and the standard graduation Ls as L1. The sign of L1 is defined as "+" when the middle graduation Lm is to the left of Ls and "-" when Lm is to the right of Ls.

[0092] Step 7: Calculate the indication error △L1 of the first target detection point of the inspected steel tape measure 1:

[0093] △L1=L1+Lg+Lx1-Lb1

[0094] Step 7: Begin testing at the second target detection point at the 2000mm scale line:

[0095] When the second target detection point Lb2 = 2000mm of the inspected steel tape measure 1 reaches the "detection position", the electric rotary table needs to rotate a horizontal target distance of Lxˊ2, Lxˊ2 = 1000mm (the distance between the 1m mark of the first target detection point and the 2m mark of the second target detection point). At this time, the motor of the rotating electric rotary table reaches the target horizontal distance Lxˊ2 = 1000mm through closed-loop control. The actual horizontal distance rotated is Lx2. The actual distance of the standard mark Ls displayed on the display screen 71 is Ls = Lg + Lx1 + Lx2. Following step six, the distance between Lm and the standard mark Ls is measured as L2. The indication error of the second target detection point is △L2.

[0096] △L2=L2+Lg+Lx1+Lx2-Lb2;

[0097] Following this pattern, complete the remaining test points meter by meter according to the JJG 4-2015 steel tape measure verification requirements, and calculate the indication error according to the formula in step seven. After the test is completed, the electric rotary table is reversed to the origin.

[0098] This utility model provides a high-precision, computer-controlled, compact, space-saving, convenient, efficient, and automated detection device for measuring the error of steel tape measure readings.

[0099] The above embodiments and figures are not intended to limit the product form and style of this utility model. Any appropriate changes or modifications made by those skilled in the art should be considered as not departing from the patent scope of this utility model.

Claims

1. A computer-controlled steel tape measure indication error detection device, characterized in that: include: The housing has a steel tape measure clamp and an electric rotary table assembly fixedly installed on the same horizontal line as the front plate of the housing. The electric rotary table assembly includes: an electric rotary table and a winding wheel mechanism connected thereto; The electric rotary table is installed inside the housing, and the rotating shaft of the winding wheel mechanism extends out of the front plate of the housing. A shaft groove is opened at one end, and the other end is fixedly connected to the electric rotary table. The top of the casing has an operation panel, and the operation panel has a display screen; The housing contains electrical components, which include: a controller, a lower-level computer, and a higher-level computer. A sheet metal mounting base is fixedly connected to the front of the front panel of the housing. A single-axis module and a grating ruler are provided on the sheet metal mounting base. The reading head on the grating ruler is fixedly connected to the side of the single-axis module through a mounting plate. A camera assembly is fixedly connected to the top of the single-axis module. The grating ruler reads the position information of the single-axis module in real time and transmits it to the lower-level machine. The camera assembly includes: a support, a column, a connecting base, a connecting plate, a camera, a fixing plate, and an LED light; the support is fixedly connected to the top of the single-axis module, and the column is fixedly connected to the top of the support; the camera is fixedly connected to the connecting base on the column via the connecting plate, and the LED light is also provided below the camera. The side of the LED light is connected to the connecting base via the fixing bracket. The camera is located above the steel tape measure being inspected, captures images of the scale of the steel tape measure being inspected, and uploads them to the lower-level machine; The single-axis module, the grating ruler, and the electric rotary table are all connected to the controller; Two rolling lifting wheel assemblies are provided at an interval between the steel tape measure clamp and the electric rotary table assembly, and are installed inside the machine housing; The two rolling lifting wheel assemblies are arranged symmetrically; Each of the rolling lifting roller assemblies has two rollers, which are respectively located above and below the steel tape measure being inspected, to realize the rotational movement and lifting and pressing action of the two rollers, for stabilizing and flattening the steel tape measure being inspected. The steel tape measure clamp includes: an L-shaped fixed bracket, two cylindrical seats, and a U-shaped support rod; the vertical end of the L-shaped fixed bracket is fixed to the front plate of the machine housing, and the two cylindrical seats are located at the horizontal end of the L-shaped fixed bracket near the vertical end; the two ends of the U-shaped support rod are bent downward and inserted into the two cylindrical seats and fixedly connected by springs. The steel tape measure to be inspected is fixedly installed on the steel tape measure clamp. The hook of the steel tape measure to be inspected is inserted into the shaft groove of the electric rotary table assembly. The steel tape measure is moved horizontally by the rotation of the electric rotary table. The display screen on the operation panel of the machine housing displays the image captured by the camera in real time and the steel tape measure indication error result calculated by the host computer.

2. The computer-controlled steel tape measure indication error detection device as described in claim 1, characterized in that: Each of the rolling lifting roller assemblies includes: a motor, a transmission mechanism, a first roller, a second roller, a first drive shaft, a second drive shaft, a third drive shaft, a gearbox, and the two rollers; The drive shaft of the motor drives the first wheel and the second wheel to rotate in the same direction through the transmission mechanism; One end of the first drive shaft is connected to the center of the first rotating wheel, and the other end is connected to the lower roller of the two rollers; One end of the second drive shaft is connected to the center of the second rotating wheel, and the other end passes through the gearbox and extends out of the gearbox; a gear transmission mechanism is provided inside the gearbox, and inside the gearbox, the second drive shaft drives the third drive shaft to rotate in the opposite direction through the gear transmission mechanism, and one end of the third drive shaft extends out of the gearbox and connects to the upper roller of the two rollers; A lifting mechanism is fixedly installed above the gearbox. The lifting mechanism includes: a lifting top plate, a lifting pressure plate, and a knob shaft. The top plate is installed on the gearbox in a sloping manner. The top of the top plate abuts against the top of the "7"-shaped lifting pressure plate. The middle part of the lifting pressure plate is fixedly connected to the extension end of the knob shaft. The bottom of the lifting pressure plate abuts against the middle part of the top plate. Rotating the knob on the knob shaft causes the lifting pressure plate to rotate, thereby pushing the top plate and raising or lowering the upper roller.

3. The computer-controlled steel tape measure indication error detection device as described in claim 2, characterized in that: The lifting plate in each of the lifting wheel mechanisms also abuts against a fine-tuning component; The two fine-tuning components are symmetrically arranged; Each of the aforementioned fine-tuning components includes: a rotary rod, a knurled wheel, a threaded support, a handwheel, and a smooth support; One end of the rotating rod is fixedly connected to the straight knurled wheel; the threaded support, the handwheel, and the smooth support are sequentially mounted on the rotating rod; The threaded support and the optical support are fixedly mounted on the front plate of the housing; A spring plate is provided at the top of the optical support, and a steel ball is provided between the spring plate and the straight knurling wheel; The other end of the rotary rod abuts against the lifting plate. By rotating the handwheel, the rotary rod presses against the lifting plate to finely adjust the distance between the two rollers.

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