A portable device for detecting the indication error of a steel tape

Abstract

A portable steel tape error detection device, comprising: a casing, the same horizontal line on the front plate of the casing is sequentially fixedly installed with a steel tape clamp, a glass fixing plate and a motorized rotary table assembly; the motorized rotary table of the motorized rotary table assembly is installed in the interior of the casing, the rotating shaft of a winding wheel mechanism extends out of the front plate of the casing, the end of the rotating shaft is provided with an axle slot, and the other end is fixedly connected with the motorized rotary table; the steel tape clamp is fixedly installed with a steel tape, and the top of the glass fixing plate is provided with a mark line parallel to the scale on the steel tape; the hook of the steel tape is inserted into the axle slot of the motorized rotary table assembly through the U-shaped groove of the glass fixing plate, the steel tape is horizontally moved by the rotation of the motorized rotary table, and the error value is obtained according to the distance between the mark line on the glass fixing plate and the target detection point scale line on the steel tape. The utility model occupies small space, is fast, accurate, efficient and convenient.

Description

Technical Field

[0001] This utility model belongs to the technical field of steel tape measure indication error calibration, specifically referring to a convenient 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 project 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, positioning blocks on the table, and clamping devices. A fixing device is also 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 through the 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 to research a space-saving steel tape measure that uses a motor to automatically extend and retract the tape measure, so as to achieve fast, accurate and convenient testing of steel tape measures. Utility Model Content

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

[0011] This utility model is implemented as follows:

[0012] A convenient device for detecting the indication error of a steel tape measure includes: a housing, wherein a steel tape measure clamp, a glass fixing plate, and an electric rotary table assembly are sequentially fixed on the same horizontal line of the front plate of the housing;

[0013] The electric rotary table assembly includes: an electric rotary table and a winding wheel mechanism connected thereto;

[0014] The electric rotary table assembly is installed inside the housing, the rotating shaft of the winding wheel mechanism extends out of the front plate of the housing, the shaft groove is opened at one end, and the other end is fixedly connected to the electric rotary table.

[0015] The steel tape measure is fixedly mounted on the steel tape measure clamp. The glass fixing plate has a U-shaped groove in the middle and a marking line at the top that is parallel to the scale on the steel tape measure.

[0016] A rolling lifting wheel assembly is provided on each side of the glass fixing plate and installed inside the housing; the two rolling lifting wheel assemblies are arranged symmetrically.

[0017] Each of the rolling lifting roller assemblies has two rollers, respectively located above and below the steel tape measure, to realize the rotational movement and lifting and pressing action of the two rollers, for stabilizing and flattening the steel tape measure;

[0018] 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.

[0019] The hook of the steel tape measure passes through the U-shaped groove of the glass fixing plate and 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, and the error value is obtained according to the distance between the marking line on the glass fixing plate and the target detection point marking line on the steel tape measure.

[0020] Furthermore, 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;

[0021] The drive shaft of the motor drives the first wheel and the second wheel to rotate in the same direction through the transmission mechanism;

[0022] 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;

[0023] 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;

[0024] 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.

[0025] 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.

[0026] Furthermore, the lifting plate in each of the lifting wheel mechanisms also abuts against a fine-tuning component;

[0027] The two fine-tuning components are symmetrically arranged;

[0028] Each of the aforementioned fine-tuning components includes: a rotary rod, a knurled wheel, a threaded support, a handwheel, and a smooth support;

[0029] 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;

[0030] The threaded support and the optical support are fixedly mounted on the front plate of the housing.

[0031] 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;

[0032] 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.

[0033] The advantages of this utility model are:

[0034] 1. The entire testing device is highly integrated, compact, and flexible, requiring minimal laboratory space.

[0035] 2. Direct measurement is achieved by generating a standard distance through an electric rotary table, which changes the traditional steel tape measure comparison method and reduces the error introduced by tensile deformation in the traditional steel tape measure inspection process;

[0036] 3. Two pairs of upper and lower rollers with adjustable gap are used to press down on the steel tape measure under inspection, which reduces the error introduced by the bending deformation of the steel tape measure itself and improves 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.

[0037] 4. The electric rotary table assembly is used to rotate the steel tape measure, which provides the initial zero position of the steel tape measure and also rolls up the tape measure after inspection, further protecting the steel tape measure and preventing the palm from being cut.

[0038] 5. A dedicated steel tape measure clamp is used to enable quick loading and unloading of the steel tape measure being inspected;

[0039] 6. A U-shaped groove on a glass fixing plate is used for the steel tape measure to pass through, and the deviation between the marking line on it and the scale line of the steel tape measure is read, making the reading convenient and efficient. Attached Figure Description

[0040] The present invention will now be further described with reference to the accompanying drawings and embodiments.

[0041] Figure 1 This is a schematic diagram of the external structure of the detection device of this utility model in use.

[0042] 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).

[0043] 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.

[0044] Figure 4 This is a schematic diagram of the first rolling lifting wheel assembly in the detection device of this utility model.

[0045] Figure 5 This is a schematic diagram of the second rolling lifting wheel assembly in the detection device of this utility model.

[0046] Figure 6 This is a schematic diagram of the first fine-tuning component in the detection device of this utility model.

[0047] Figure 7 This is a schematic diagram of the second fine-tuning component in the detection device of this utility model.

[0048] Figure 8 This is a schematic diagram of the winding wheel mechanism in the detection device of this utility model.

[0049] Figure 9 This is a structural schematic diagram of the steel tape measure clamp in the testing device of this utility model.

[0050] Figure 10 This is a schematic diagram of the glass fixing plate in the detection device of this utility model.

[0051] Figure 11 This is a block diagram of the system control principle in the detection device of this utility model. Detailed Implementation

[0052] like Figures 1 to 11 As shown, a convenient steel tape measure indication error detection device includes: a housing 4, and a steel tape measure clamp 11, a glass fixing plate 2, and an electric rotary table assembly 3, which are sequentially fixed on the same horizontal line as the front plate 41 of the housing 4.

[0053] 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.

[0054] A steel tape measure 1 is fixedly mounted on a steel tape measure clamp 11. The glass fixing plate 2 has a U-shaped groove in the middle and a marking line 21 on the top that is parallel to the scale on the steel tape measure 1.

[0055] The hook of the steel tape measure 1 passes through the U-shaped groove of the glass fixing plate 2 and is inserted into the shaft groove 3211. The steel tape measure 1 is moved horizontally by the rotation of the electric rotary table 31. The error value is obtained according to the distance between the marking line 21 on the glass fixing plate 2 and the target detection point marking line on the steel tape measure 1.

[0056] A rolling lifting wheel assembly (first rolling lifting wheel assembly 51 and second rolling lifting wheel assembly 52) is provided on each side of the glass fixing plate 2, and is installed inside the housing 4;

[0057] The first rolling lifting wheel assembly 51 and the second rolling lifting wheel assembly 52 are symmetrically arranged and have the same structure;

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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;

[0062] 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.

[0063] 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.

[0064] 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.

[0065] The two fine-tuning components 61 and 62 are symmetrically arranged and have the same structure;

[0066] 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.

[0067] 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.

[0068] 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.

[0069] The drive of the electric rotary table 31 and the two rolling lifting wheel assemblies 51 and 52 are achieved through the design of a control circuit board (system control principle block diagram as shown in the figure). Figure 11 As shown, it can achieve precise positioning to each target detection point. The operation screen 7 on the control panel 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.

[0070] The specific testing method includes the following steps:

[0071] Step 1: Place the steel tape measure 1, glass fixing plate 2, and electric rotary table assembly 3 on the same horizontal line of the front plate 41 of the housing 4 in sequence;

[0072] Step 2: Pull out the hook of the steel tape measure 1, pass it through the glass fixing plate 2, and insert the hook into the shaft groove 3211 of the rotating shaft 321 of the rolling wheel mechanism 32;

[0073] Step 3: Zero the electric rotary table 31;

[0074] Step 4: Begin testing at the first target detection point, 1000mm scribed line:

[0075] The fixed distance Lg between the marking line 21 on the glass fixing plate 2 and the left side of the shaft groove 3211 of the rotating shaft 321 is measured.

[0076] Calculate the horizontal target distance Lx′1 that the electric rotary table 31 needs to rotate, Lx′1=Lb1-Lg, where Lb1 is the nominal value of the first target detection point, i.e., 1000mm. (Assuming the Lg reading is 250.01mm, then Lx′1=Lb1-Lg=1000-250.01=749.99mm). Rotate the electric rotary table 31 to reach the horizontal target distance Lx′1, and read the deviation value L1 between the marking line on the glass fixing plate 2 and the marking line of the first target detection point at this time. Obtain the error value △L1=-L1 of the first target detection point.

[0077] Step 5: Begin testing at the second target detection point, the 2000m mark:

[0078] The electric rotating stage 31 reaches the horizontal target distance Lx′2, Lx′2=Lb2-Lb1=2000mm-1000mm, where Lb2 is the nominal value of the second target detection point, i.e. 2000mm. The deviation value L2 between the marking line on the glass fixing plate 2 and the 2000mm mark of the second target detection point is read, and the error value △L2=-L2 of the second target detection point is obtained.

[0079] Following this pattern, the remaining inspection points are completed meter by meter according to the JJG 4-2015 steel tape measure inspection requirements. After the inspection is completed, the electric rotary table 31 is reversed to the origin.

[0080] This invention features a highly integrated, compact, and flexible testing device that requires minimal laboratory space. It achieves direct measurement by generating a standard distance using an electric rotary table, replacing the traditional comparative method of steel tape measure measurement and reducing errors introduced by tensile deformation during the traditional process. Two pairs of adjustable-gap upper and lower rollers, designed to protect the steel tape measure, press down on the rolled steel, minimizing errors caused by the tape measure's own curling deformation and improving testing accuracy. These rollers also facilitate loading and unloading. The electric rotary table drives a winding wheel mechanism to rotate, enabling the tape measure to be unloaded and retracted. This provides an initial zero position for the tape measure and also retracts the measured tape, further protecting it and preventing hand injuries. A dedicated steel tape measure clamp allows for quick loading and unloading. A U-shaped groove on a glass fixing plate allows the tape measure to pass through, and the deviation between the markings and the tape measure's graduations is read, making reading convenient and efficient.

[0081] 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 convenient device for detecting the indication error of a steel tape measure, characterized in that: include: The housing, on the same horizontal line of the front plate of the housing, has a steel tape measure clamp, a glass fixing plate, and an electric rotary table assembly fixedly installed in sequence; The electric rotary table assembly includes: an electric rotary table and a winding wheel mechanism connected thereto; The electric rotary table of the electric rotary table assembly is installed inside the housing, and 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 steel tape measure is fixedly mounted on the steel tape measure clamp. The glass fixing plate has a U-shaped groove in the middle and a marking line at the top that is parallel to the scale on the steel tape measure. A rolling lifting wheel assembly is provided on each side of the glass fixing plate and installed inside the housing; the two rolling lifting wheel assemblies are arranged symmetrically. Each of the rolling lifting roller assemblies has two rollers, respectively located above and below the steel tape measure, to realize the rotational movement and lifting and pressing action of the two rollers, for stabilizing and flattening the steel tape measure; 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 hook of the steel tape measure passes through the U-shaped groove of the glass fixing plate and 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, and the error value is obtained according to the distance between the marking line on the glass fixing plate and the target detection point marking line on the steel tape measure.

2. The convenient 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 convenient 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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