Skateboard Checkweigher

Abstract

A skateboard checkweigher, comprising a weight transmission member, a weighing sensor, a smooth sliding contact surface on the top of the weight transmission member, the sliding contact surface being a plane and perpendicular to the load-bearing direction of the weighing sensor, the weight transmission member being rigidly connected to the load-bearing end of the weighing sensor, and a belt conveyor running along the material conveying direction, the belt conveyor comprising at least one belt, the left and right sides of the upper part of the belt conveyor having a roller shaft, respectively a left roller shaft and a right roller shaft, the belt passing over the left roller shaft and the right roller shaft, the portion of the belt between the upper vertex of the left roller shaft and the upper vertex of the right roller shaft being called the inter-axial upper belt, the weight transmission member being located between the left roller shaft and the right roller shaft, the sliding contact surface being in sliding contact with a portion of the lower surface of the inter-axial upper belt, BC being greater than WC, the axes of the left roller shaft and the right roller shaft being parallel to each other and both being parallel to the sliding contact surface.

Description

Technical Field

[0001] The present invention relates to the field of skateboard checkweighers, and in particular to skateboard checkweighers in which a weight conducting part of a soft belt supporting an object is arranged horizontally or tilted at a small angle. Background Art

[0002] Many items, such as various boxed, bottled or bagged medicines or foods, various irregularly shaped local products, aquatic products or industrial products, need to be checked by a checkweigher on the production line to check whether their weight is qualified or whether there are missing or extra pieces, or to be graded according to weight.

[0003] Slide checkweighers with a weight-conducting member whose upper surface is tilted downward at a large angle have been widely used in production lines due to their high precision.

[0004] The slide checkweigher includes a base, a material sliding slide, a weight conductor, and an electric control cabinet. The object being weighed slides over the upper surface of the weight conductor and is weighed at the same time. The weight conductor is rigidly connected to the load-bearing end of the weighing sensor below it, the fixed end of the weighing sensor is rigidly connected to the base, and the weighing sensor is electrically connected to the electric control cabinet. The upper surface of the weight conductor is very smooth to reduce the friction resistance of the object sliding over. The upper surface of the weight conductor is also very flat to reduce the jumping, bumping, horizontal spinning, and up and down rolling of the object when sliding over. The upper surface of the weight conductor is perpendicular to the load-bearing direction of the weighing sensor, eliminating the influence of friction on the weighing result, and achieving a higher weighing accuracy. The weight conductor is mostly made of a thin steel plate.

[0005] The upper surface of the weight transmission part is tilted downward at a large angle. The object slides on the weight transmission part and is weighed by the initial velocity and height potential energy. Since there is no interference from the rotating parts to the weighing sensor, and the weighing sensor has no other interference and contact constraints from the object on the skateboard, the length of the weight transmission part along the direction of the object can be designed to be very long in order to greatly increase the weighing time. Therefore, the weighing accuracy of the skateboard scale is very high. Since the weight transmission part is very light, a weighing sensor with a smaller range can be selected to improve the weighing accuracy. At the same time, the weight transmission part and the weighing sensor are directly rigidly fixed, which also ensures that the natural frequency of the elastic system composed of the weight transmission part and the weighing sensor is very high, and the weight transmission reaction is extremely fast. Therefore, the skateboard checkweigher is not only more accurate than the belt checkweigher, but also can adapt to high-speed weighing. Therefore, the skateboard checkweigher with the upper surface of the weight transmission part tilted downward at a large angle is widely used in production lines.

[0006] However, the skateboard checkweigher has the following disadvantages:

[0007] 1. The bottom surface of the object to be weighed must be very smooth, and the friction with the upper surface of the weight transmission part must be very small. In particular, the surface of the object to be weighed must be dry and non-sticky.

[0008] 2. The bottom surface of the object to be weighed should be as flat as possible. Otherwise, the object may spin or flip due to the friction or resistance with the slide, which will seriously affect the weighing accuracy.

[0009] 3. The object to be weighed must have a low center of gravity. It is not suitable for checking the weight of open liquid containers, because the downward-tilted weight conductor will cause the open liquid container to spill liquid, and the horizontally arranged weight conductor will slow down due to the resistance at the bottom of the object and the top will tilt forward and spill liquid. Similarly, closed containers are not suitable because the liquid will sway inside the container, making it impossible to weigh accurately.

[0010] 4. It must be tilted more than 20°.

[0011] For various commonly used paper boxes, plastic bags and other packaging products, when the angle of the upper surface of the weight conductor is less than 15°, the sliding force of the weight of the object being weighed relative to the surface of the slide becomes smaller, the sliding friction becomes larger, the sliding posture and speed of the object become unstable, and stable weighing with high precision cannot be achieved. When the upper surface of the weight conductor is arranged horizontally or at a small angle of less than 15°, low-speed objects cannot slide through the weight conductor. The length of the weight conductor must be short, and only medium- and high-speed objects with very smooth bottoms are allowed to slide through the weight conductor by inertia. However, during the sliding of medium- and high-speed objects, the friction between the bottom points of the object and the slide is inconsistent each time, resulting in a change in sliding posture and a slower sliding speed. Moreover, the same object slides on the slide at the same initial velocity and posture each time, especially at different speeds when rushing out of the slide. In particular, the length of the weight conductor is very short, resulting in a short load time for the weighing sensor and less weight data sampling, which will seriously affect the weighing data processing and thus the weighing accuracy.

[0012] Therefore, the skateboard checkweigher is not suitable for situations where the skateboard must be arranged horizontally or at a small inclination angle of less than 15°.

[0013] However, in fact, many production lines can only transport horizontally, and the weighing platform of the checkweigher must be arranged horizontally or at a small inclination angle of less than 15°.

[0014] 5. It is not suitable for production lines where the subsequent process has strict requirements on the posture of the weighed object, because the existing technology may rotate or roll the object during the sliding check weighing process. For example, many boxed products need to be coded on a specific part of the packaging box after check weighing, and the packaging box must not rotate during check weighing. For another example, the object needs to be boxed after check weighing, and the check weighing also requires that the object's posture should not change.

[0015] These shortcomings seriously restrict the widespread application of slide plate checkweighers, especially their use in production lines that horizontally transport objects to be weighed. Summary of the invention

[0016] The present invention provides a skateboard checkweigher.

[0017] The technical measures adopted in the present application are: a skateboard checkweigher, which includes a weight transmission part, a weighing sensor, and a smooth sliding contact surface on the top of the weight transmission part, the sliding contact surface is a rectangular plane and is perpendicular to the load-bearing direction of the weighing sensor, the weight transmission part is rigidly connected to the load-bearing end of the weighing sensor, and also includes a belt conveyor device running along the material conveying direction, the belt conveyor device includes a belt, and there is a roller on the left and right of the upper part of the belt conveyor device, respectively, a left roller and a right roller, the belt passes over the left roller and the right roller, and the part of the belt located between the upper vertex of the left roller and the upper vertex of the right roller is called the upper belt between the axes, the weight transmission part is located between the left roller and the right roller, the sliding contact surface is in sliding contact with part of the lower surface of the upper belt between the axes, the length of the object to be weighed along the running direction of the belt is WC, the length of the sliding contact surface along the running direction of the belt is BC, BC is greater than WC, and the axes of the left roller and the right roller are parallel to each other and are both parallel to the sliding contact surface.

[0018] The specific features of this scheme include: the distance between the vertex of the left roller section and the leftmost contact point of the upper belt between the shafts and the sliding contact surface is ZC; when the object to be weighed is directly pressed on the weighing sensor without the upper belt between the shafts, the downward displacement of the load-bearing end of the weighing sensor is h, and the length of ZC needs to ensure: 57.3×h<ZC<WC / 2.

[0019] The distance between the rightmost contact point of the belt and the sliding contact surface between the shafts and the vertex of the right roller is YC, and YC must be guaranteed and 57.3×h<YC<WC / 2.

[0020] The belt conveyor consists of two independent and parallel belts with only one sliding contact surface on the top of the weight transmission element.

[0021] The weight transmission element has two independent sliding contact surfaces of the same shape and size, the long side of each sliding contact surface is arranged along the running direction of the belt, and the height of other parts of the weight transmission element outside the two sliding contact surfaces is lower than that of the two sliding contact surfaces.

[0022] The weight conductor has two independent sliding contact surfaces of the same shape and size, the long side of each sliding contact surface is arranged along the running direction of the belt, and the height of other parts of the weight conductor located outside the two sliding contact surfaces is lower than the height of the two sliding contact surfaces; it also includes two independent and parallel belts; the two belts are in sliding contact with the corresponding sliding contact surfaces respectively.

[0023] A material-sliding slide is also provided between the left roller and the sliding contact surface. The top of the material-sliding slide is a smooth plane. The top plane of the material-sliding slide is coplanar or parallel to the sliding contact surface. The top plane of the material-sliding slide is in sliding contact with the belt between the shafts. The top plane of the material-sliding slide is not lower than the sliding contact surface. The distance between the rightmost end point of the material-sliding slide in contact with the belt between the shafts and the leftmost contact point between the belt between the shafts and the sliding contact surface is SC, and the SC length must meet the following conditions: 57.3×h<SC<WC / 2.

[0024] A discharging slide plate is also arranged between the weight transmission part and the right roller. The top of the discharging slide plate is a smooth plane. The top plane of the discharging slide plate is coplanar or parallel to the sliding contact surface. The top plane of the discharging slide plate is in sliding contact with the upper belt between the shafts. The top plane of the discharging slide plate is not higher than the sliding contact surface. The distance between the rightmost end point where the sliding contact surface contacts the upper belt between the shafts and the leftmost contact point between the upper belt between the shafts and the discharging slide plate is CC. The length of CC needs to meet the following conditions: 57.3×h<CC<WC / 2.

[0025] A material-sliding slide is also provided between the left roller and the sliding contact surface. The top of the material-sliding slide is a smooth plane. The top plane of the material-sliding slide is in sliding contact with the belt between the shafts. The distance between the rightmost end point where the material-sliding slide contacts the belt between the shafts and the leftmost contact point between the belt between the shafts and the sliding contact surface is SC. The length of SC must meet the following conditions: 57.3×h<SC<WC / 2;

[0026] The top plane of the material-sliding slide is slightly inclined to the upper right relative to the sliding contact surface, and the angle A between them is less than 10°. The linear velocity of the belt is V, g is the local acceleration of gravity, and the vertical distance from the leftmost contact point of the belt on the sliding contact surface and the shaft to the top plane of the material-sliding slide is ZJ, ZJ>0.5×g×SC×SC / (V×V).

[0027] A discharging slide plate is also provided between the weight transmission part and the right roller shaft. The top of the discharging slide plate is a smooth plane. The top plane of the discharging slide plate is in sliding contact with the upper belt between the shafts. The distance between the rightmost end point where the sliding contact surface contacts the upper belt between the shafts and the leftmost contact point between the upper belt between the shafts and the discharging slide plate is CC. The length of CC needs to ensure: 57.3×h<CC<WC / 2;

[0028] The top plane of the discharge slide is slightly inclined to the lower right relative to the sliding contact surface and the angle B between them is less than 10°. The vertical distance from the leftmost contact point of the belt between the discharge slide and the shaft to the sliding contact surface is YJ, YJ>0.5×g×CC×CC / (V×V).

[0029] The belt conveyor is a multi-roller structure, and includes a third roller below the plane where the left roller and the right roller are located. There is enough space between the belt and the third roller to install a weight transmission component and a weighing sensor.

[0030] It also includes a base and an electric control cabinet. The fixed end of the weighing sensor is rigidly connected to the base, and the weighing sensor is electrically connected to the electric control cabinet. The belt conveyor has only two rollers, the left roller and the right roller, wherein the left roller is a driven shaft and the right roller is an active roller. The right roller is driven by a motor. The weighing sensor is interspersed between two parallel belts, the base is outside the two belts, and the weight transmission part is tightly connected to the weighing sensor. The sliding contact surface is a rectangular plane.

[0031] The cross-section of the weight conductor perpendicular to the running direction of the belt is a "concave" structure, and protrusions are set upward on both sides of the weight conductor; the upper surfaces of the two protrusions are sliding contact surfaces; the width of the sliding contact surface is less than or equal to the width of the belt in sliding contact with it, and the upper surface height of the middle part of the weight conductor is lower than the long smooth planes on both sides.

[0032] The "concave" structure of the weight transmission part and the protrusions therein are formed by bending a whole plate, and the bending line is parallel to the running direction of the belt.

[0033] The cross-section of the weight conductor perpendicular to the running direction of the belt is a "concave" structure, and protrusions are arranged upward on both sides of the weight conductor; the "concave" structure of the weight conductor includes a "concave" frame made of lightweight material and a hard guide rail with a smooth upper surface fixedly connected to the protrusions on the two side surfaces of the "concave" frame, the length direction of the hard guide rail is consistent with the running direction of the belt, and the upper surface of the hard guide rail is the sliding contact surface.

[0034] A belt conveyor for removing unqualified objects is connected behind the right roller. Two pneumatic nozzles are overlapped and arranged on the belt conveyor for removal. Each air nozzle corresponds to a solenoid valve, and the two pneumatic nozzles point to the same direction and position.

[0035] This solution greatly expands the application scope of the existing skateboard checkweigher and greatly improves the technical effect of the existing checkweigher, producing the following beneficial effects:

[0036] 1. High-precision weighing is achieved, exceeding the accuracy of existing skateboard checkweighers.

[0037] Since the belt is soft, after calibration, the influence of the initial tension of the belt and the incremental tensile stress of the belt caused by the downward movement of the load-bearing end of the weighing sensor in the plumb bob direction on the weighing result of the weighed object is completely compensated. In addition, the belt power is used to push the weighed object to slide over the weight conductor. The length of the weight conductor along the moving direction of the object can be made very long to ensure that the weighing sensor can sample more data. It can also slide over the weight conductor at a controllable speed, while the speed and posture of the weighed object on the large-angle tilted skateboard checkweigher are completely free and uncontrollable. Therefore, the weighing accuracy of the present application is very high, exceeding the weighing accuracy of the large-angle tilted skateboard checkweigher.

[0038] 2. It can be used for ultra-low speed weighing as well as ultra-high speed weighing, which far exceeds the speed range of existing skateboard checkweighers.

[0039] Since the object being weighed does not directly contact the weight transmission part, it does not need to rush through the slide plate by speed inertia, but is supported by the belt, and the speed of the belt supporting the object is constant. The high-speed moving object will not slow down, spin or flip due to friction resistance. The weighing sampling is very stable, ensuring the high precision of the weighing result. Since the belt supports the object, slow-moving objects (such as containers filled with liquids) can also slide smoothly and be weighed with high precision.

[0040] 3. Because of the smooth support of the belt, objects with rough, wet or even sticky bottoms can also be weighed using the skateboard. For example, some objects have rough bottoms, and even if the skateboard is tilted more than 20°, the skateboard checkweigher cannot be used normally. The solution of this application greatly expands the scope of use of existing skateboard scale technology.

[0041] 4. Because of the stable support of the belt, objects with uneven bottoms can also be checked by the slide plate.

[0042] 5. Because of the stable support of the belt, containers containing various liquids can also be weighed with high precision.

[0043] 6. Because of the smooth support of the belt, the center of gravity of the object being weighed is no longer required to be low. Tall bottles and tall boxes can be weighed and will not tip over during sliding weighing.

[0044] 7. Because two parallel belts with a certain interval are set, the installation of the weight transmission part, the weighing sensor and the base is extremely convenient. The weight transmission part can be fixed or removed directly between the two belts. Objects with uneven bottoms can be carried by the two belts for more stable operation.

[0045] 8. The "concave" structure of the weight transmission part can smoothly move objects with uneven bottoms to achieve high-precision weighing.

[0046] 9. The loading slide, discharging slide and weight transmission parts are installed on a base, which is very convenient to replace and adjust the belt without affecting the original weighing parameter settings and weighing accuracy.

[0047] 10. The "concave" structure of the material-sliding slide, weight-conducting part, and discharging slide is made of sheet metal bending, which is smoother, more convenient, and has a low cost. Due to the consistency of the "concave" structure of the material-sliding slide, weight-conducting part, and discharging slide, the weighing accuracy is higher. Smooth hard strips are fixed on the upper surface of the two raised sides of the "concave" frame to reduce the replacement cost.

[0048] 11. Suitable for production lines that have strict requirements on the posture of objects after weight inspection, such as coding, boxing, and palletizing after weight inspection.

[0049] 12. The slide plate checkweigher is no longer limited to an inclination greater than 20°. It is not only suitable for horizontal arrangement of the upper surface of the weight transmission part or arrangement with a small inclination angle less than 15°, but also suitable for all inclination angles suitable for the existing slide plate checkweigher. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is a three-dimensional structural diagram of this application. Figure 2 It is a schematic front view of the structure of the present application. Figure 3 A schematic diagram of the structure of the feed slide and the discharge slide is provided for this application. Figure 4 This is a schematic diagram showing that the relative sliding contact surfaces of the loading slide and the discharging slide are tilted at a small angle. Figure 5 for Figure 1 Left side cross-sectional view. Figure 6 This is a three-dimensional schematic diagram of the structure where the weight transmission part is bent from a whole plate. Figure 7 for Figure 6 The left side schematic diagram of Figure 8 This is a three-dimensional schematic diagram of a weight transmission part consisting of a concave structure and a guide rail. Fig. 9 for Figure 8 Schematic diagram of the left side.

[0051] In the figure, 1-weight transmission part, 2-weighing sensor, 3-base, 4-belt, 5-feeding slide, 6-discharging slide, 7-object to be weighed, 8-left roller, 9-right roller, 11-fastener, 12-"concave" frame, 13-hard guide rail, 14-sliding contact surface, 19-motor, ZC-the distance between the left roller vertex or the rightmost contact point between the belt and the feed-following slide relative to the leftmost contact point between the belt and the sliding contact surface between the axes, YC-the distance between the rightmost contact point between the belt and the sliding contact surface between the axes relative to the right roller vertex or the leftmost contact point between the belt and the discharging slide, WC-the length of the object to be weighed along the running direction of the belt, SC-the distance between the feed-following slide and the axis - The distance between the rightmost end point of the upper belt contact between the shafts and the leftmost contact point between the upper belt and the sliding contact surface, CC - The distance between the rightmost end point of the sliding contact surface and the upper belt between the shafts and the leftmost contact point between the upper belt and the discharge slide, ZJ - The vertical distance between the leftmost contact point of the sliding contact surface and the upper belt between the shafts to the top plane of the feed slide, YJ - The vertical distance between the leftmost contact point of the discharge slide and the upper belt between the shafts and the sliding contact surface, A - The angle between the top plane of the feed slide and the sliding contact surface tilted to the upper right, B - The angle between the top plane of the discharge slide and the sliding contact surface tilted to the lower right, Arrow - Belt running direction, BC - The length of the sliding contact surface along the belt running direction. DETAILED DESCRIPTION

[0052] Example 1: A skateboard checkweigher, see Figure 1 and 2 , including a weight transmission member 1, a weighing sensor 2, a base 3, and an electric control cabinet, wherein the fixed end of the weighing sensor 2 is rigidly connected to the base 3, the weighing sensor 2 is electrically connected to the electric control cabinet, the top of the weight transmission member 1 has a smooth rectangular plane, which is called a sliding contact surface 14 and is perpendicular to the load-bearing direction of the weighing sensor 2, the weight transmission member 1 is directly and only rigidly connected to the load-bearing end of the weighing sensor 2, and also includes a belt conveyor device, the belt conveyor device includes a belt 4, such as Figure 2 As shown by the middle arrow, the portion of the belt 4 located on the upper part of the belt conveyor runs from left to right. There is a roller on the left and right of the upper part of the belt conveyor, namely the left roller 8 and the right roller 9. The belt 4 passes over the left roller 8 and the right roller 9. The portion of the belt 4 between the upper apex of the left roller 8 and the upper apex of the right roller 9 is called the upper belt between axes. The belt is thin and soft. The tensile tension applied to the belt 4 by the belt conveyor makes the upper belt between axes almost flat. The weight transmission member 1 is located between the left roller 8 and the right roller 9. The sliding contact surface 14 is in sliding contact with part of the lower surface of the upper belt between axes. The length of the object 7 to be weighed along the running direction of the belt is WC, and the length of the sliding contact surface 14 along the running direction of the belt 4 is BC, BC is greater than WC, and the axes of the left roller 8 and the right roller 9 are parallel to each other and to the sliding contact surface 14.

[0053] The belt conveyor device only includes one belt 4, and the belt conveyor device only has two rollers, namely the left roller 8 and the right roller 9, wherein the left roller 8 is the driven shaft and the right roller 9 is the active roller. The right roller 9 is driven by a motor 19, and there is only one sliding contact surface 14 on the top of the weight transmission member 1.

[0054] The apex of the cross section of the left roller 8 is not lower than the sliding contact surface 14 , and the apex of the cross section of the right roller 9 is not higher than the sliding contact surface 14 .

[0055] The distance between the vertex of the cross section of the left roller shaft 8 and the leftmost contact point between the upper belt between the shafts and the sliding contact surface 14 is ZC. When the object 7 to be weighed is directly pressed on the weighing sensor 2 without the upper belt between the shafts, the downward displacement of the load-bearing end of the weighing sensor 2 is h. The length of ZC needs to ensure: 57.3×h<ZC<WC / 2.

[0056] 57.3×h<ZC can ensure that the check weight error caused only by the belt tension from the left roller 8 direction is within 25mg under the following working conditions: two belts, each with a thickness of 0.17mm, a width of 20mm, a belt tension of 1000g, PVC material, a weighing sensor range of 6000g, and a maximum deflection of the load-bearing end of the weighing sensor of 0.36mm. At this time, when the angle change caused by moving one end of the straight long ZC belt down by h is 1°, the sum of the original tension of the belt and the tension increased by the elongation of the belt is 160g. The theoretical error rate caused by the interchange of the sine function and the tangent function in the simplified mathematical model is 0.000152305, and the error caused by the tension after multiplying the two is about 0.025g. Therefore, if the tension error caused by the inevitable function conversion error in the subsequent digital processing of the weighing results of the present invention is to be controlled within 25 mg, arctg(h / ZC) <1° is required, that is, ZC>h / tg(1°)= 57.3×h. If arctg(h / ZC) >1°, the error will increase sharply.

[0057] ZC<WC / 2 can ensure that the center of gravity of the object 7 to be weighed is still on the top of the left roller shaft 8 when it crosses over the upper sliding contact surface 14 from the top of the left roller shaft 8, thereby preventing the bottom right edge of the object 7 to be weighed from impacting the left edge of the sliding contact surface 14, so that the object 7 to be weighed can be smoothly moved onto the sliding contact surface 14, reducing weighing errors.

[0058] The distance between the rightmost contact point between the belt and the sliding contact surface 14 between the shafts and the vertex of the right roller 9 is YC, and YC needs to be ensured and 57.3×h<YC<WC / 2.

[0059] The principle of limiting the length of the belt between the relative sliding contact surface 14 at the vertex of the left roller 8 and the leftmost contact point of the belt on the shaft is the same. 57.3×h<YC can ensure that the weight check error caused only by the belt tension from the right roller 9 direction is within 25mg under the following working conditions: two belts, thickness 0.17mm, width 20mm, belt tension 1000g, belt elastic modulus 70GPa, weighing sensor range 6000g, weighing sensor load-bearing end maximum deflection 0.36mm.

[0060] YC<WC / 2 can ensure that the center of gravity of the object 7 to be weighed is still on the sliding contact surface 14 when it crosses over the top of the right roller 9 from the sliding contact surface 14, thereby preventing the bottom right edge of the object 7 to be weighed from impacting the top of the right roller 9, so that the object 7 to be weighed can be smoothly moved onto the right roller 9, reducing weighing errors.

[0061] In fact, through calibration, the influence of the sum of the original tension of the belt 4 and the tension increment caused by the elongation of the belt 4 due to the downward movement of the sliding contact surface 14 after being loaded on the load sensor 2 can be further greatly reduced.

[0062] The SCW-PLAC6000 weight check control module with digital filtering function produced by Shandong Xitai Instrument Co., Ltd. is used. There is only one belt 4, which is 120mm wide and 0.17mm thick. The belt 4 tension is 6000g, made of PVC. The weighing sensor 2 has a range of 6000g. The maximum deflection of the load-bearing end of the weighing sensor 2 is 0.36mm. A 50g paper packaging box is weighed. The length of the packaging box along the length direction of the belt 4 is WC=60mm, the length along the width direction of the belt 4 is 106mm, the height is 12mm, and the Z C=YC=20mm, there is only one rectangular sliding contact surface 14 between the weight transmission part 1 and the upper belt of the shaft, the length of the sliding contact surface 14 along the running direction of the object is BC=150mm, and the width perpendicular to the running direction of the object is 130mm. The packaging box makes the load-bearing end of the weighing sensor 2 move down by h=0.003mm, and the angle change caused by the 50g load is 0.0086°. Although it causes a 1.8g plumb force component, the influence of the plumb force component on the weighing result is offset by the digital calibration before the test. The production line speed is 400 boxes per minute, and the belt 4 speed is 75 meters / minute. The actual weighing accuracy of this solution reaches 0.31g.

[0063] The existing belt checkweigher has a weighing platform length of 150 mm and also uses the SCW-PLAC6000 checkweighing module of Shandong Xitech Instrument Co., Ltd. When testing the same object at 400 boxes / minute, the belt speed is also 75 meters / minute, and the best accuracy is only 0.4g. Therefore, the mechanical structure of the present application greatly improves the weighing accuracy of the existing technology.

[0064] Example 2, a skateboard checkweigher, is similar to Example 1 and will not be described in detail. The difference is that it includes two independent and parallel belts 4, each of which has a width of 20 mm, and the spacing between the center lines of the two belts 4 along the running direction of the belts is also 66 mm. The tension of each belt 4 is 1000 g, and the 50 g load brings a plumb bob force component of 0.6 g, which can still be offset by digital calibration processing before testing.

[0065] The two belts 4 carry the object 7 to be weighed and move over the sliding contact surface 14. Only the unevenness of the bottom surface of the object 7 in contact with the belts 4 may affect the smoothness of the movement. In this way, the requirements of the slide checkweigher on the flatness of the bottom surface of the object 7 to be weighed can be reduced.

[0066] The total mass of the two belts 4 is much smaller than that of the belts in Example 1. The interference of the unevenness caused by the seams of the belts 4 on the weight conductor 1 and the interference of the mass imbalance at each point of the belts 4 on the weight conductor 1 are greatly reduced.

[0067] Under the same test conditions as in Example 1, the actual weighing accuracy of this solution reached 0.28g, which further improved the weighing accuracy compared with Example 1.

[0068] Embodiment 3, a skateboard checkweigher, is similar to Embodiment 1 and will not be described in detail. The difference is that the weight conductor 1 has two independent sliding contact surfaces 14 of the same shape and size, the long side of each sliding contact surface 14 is arranged along the running direction of the belt and has a long side length of 150 mm and a width of 20 mm. The distance between the center lines of the two sliding contact surfaces 14 along the running direction of the object belt is 66 mm, and the height of the other parts of the weight conductor 1 outside the two sliding contact surfaces 14 is lower than the height of the two sliding contact surfaces 14.

[0069] The 120 mm wide belt 4 supports the object 7 to slide on the two sliding contact surfaces 14. Only the unevenness of the bottom surface of the object 7 located above the sliding contact surface 14 may affect the smoothness of the object's movement. In this way, the requirements of the slide checkweigher on the flatness of the bottom surface of the object 7 can be reduced.

[0070] A belt 4 supports the object 7 to be weighed and can also prevent the contents of the object from leaking and affecting the weighing.

[0071] Although there are still interferences from the uneven seams of the 120 mm wide belt 4 and the unbalanced mass, the influence of the unevenness of the bottom surface of the object 7 to be weighed on the weighing accuracy is completely eliminated.

[0072] Under the same test conditions as in Example 1, the actual weighing accuracy of this solution reached 0.25g, which further improved the weighing accuracy compared with Example 1.

[0073] Example 4, a skateboard checkweigher, is similar to Example 1 and is not described in detail. The difference is that the features are as follows: Figure 1 and 2 and 5, the weight transmission member 1 has two independent sliding contact surfaces 14 of the same shape and size, the long side of each sliding contact surface 14 is arranged along the running direction of the belt and has a long side length of 150 mm and a width of 20 mm, the distance between the center lines of the two sliding contact surfaces 14 along the running direction of the object belt is 66 mm, and the height of the other parts of the weight transmission member 1 located outside the two sliding contact surfaces 14 is lower than the height of the two sliding contact surfaces 14;

[0074] It also includes two independent and parallel belts 4. The width of the two belts 4 is 20mm respectively. The tension of each belt 4 is 1000g. The 50g load brings a plumb force component of 0.60016g, but through the digital calibration processing before the test, the influence of the plumb force on the weighing result is offset; the spacing between the center lines of the two belts 4 along the running direction of the belts is also 66mm.

[0075] The two belts 4 are in sliding contact with the two sliding contact surfaces 14 respectively.

[0076] The center lines of the two belts 4 along the belt running direction coincide with the center lines of the two sliding contact surfaces 14 along the belt running direction respectively.

[0077] Since the height of the other parts of the weight conductor 1 located outside the two sliding contact surfaces 14 is lower than the height of the two long strip planes, the parts of the object 7 to be weighed that are not in contact with the belt 4 cannot contact the weight conductor 1. The object 7 to be weighed is moved by the two belts 4, and the influence of the unevenness of the bottom surface of the object 7 to be weighed on the weighing accuracy is completely eliminated, which can greatly reduce the requirements of the slide plate checkweigher on the flatness of the bottom surface of the object 7 to be weighed.

[0078] The total mass of the two belts 4 is much smaller than that of the belts in Example 1. The interference of the unevenness caused by the seams of the belts 4 on the weight conductor 1 and the interference of the mass imbalance at each point of the belts 4 on the weight conductor 1 are greatly reduced.

[0079] Under the same test conditions as in Example 1, the actual weighing accuracy of this solution reached 0.23g, which further improved the weighing accuracy compared with Example 1.

[0080] Example 5, skateboard checkweigher, see Figure 3The same points as those in the fourth embodiment are not described in detail. The difference is that a material-smoothing slide plate 5 is provided between the left roller 8 and the sliding contact surface 14.

[0081] The top of the material-adjusting slide plate 5 is a smooth plane, the top plane of the material-adjusting slide plate 5 is parallel to the sliding contact surface 14, the top plane of the material-adjusting slide plate 5 is in sliding contact with the upper belt between the shafts, the top plane of the material-adjusting slide plate 5 is not lower than the sliding contact surface 14, the distance between the rightmost end point of the material-adjusting slide plate 5 in contact with the upper belt between the shafts and the leftmost contact point of the upper belt between the shafts and the sliding contact surface 14 is SC, and the same as the limiting principle of the relevant ZC and YC in Example 1, the SC length needs to ensure: 57.3×h<SC<WC / 2. The cross-sectional shape of the material-adjusting slide plate 5 is the same as that of the weight transmission member 1, so that the object 7 to be weighed can be more smoothly crossed from the material-adjusting slide plate 5 to the sliding contact surface 14 when being supported by the belt 4, and will not impact the weighing sensor belt 2, which can greatly improve the weighing accuracy and adapt to the weighing of high-speed objects. Because, compared with the sliding contact surface 14 that directly connects to the left roller 8, the material-sliding slide 5 is provided to guide the object 7 to be weighed, which greatly increases the stability of the object 7 to be weighed when sliding on the contact surface 14. Moreover, since the cross-sectional shape of the material-sliding slide 5 is the same as that of the weight transmission member 1, the concave guide rail traces at the bottom of the object 7 to be weighed are more consistent, and the transition is smoother. The material-sliding slide 5 is rigidly connected to the base 3, so that the relative position of the material-sliding slide 5 and the base 3 and the weighing sensor 2 and weight transmission member 1 thereon is fixed. When adjusting the position of the belt 4 of the belt conveyor mechanism relative to the weight transmission member 1, the relative position of the material-sliding slide 5 and the sliding contact surface 14 will not be changed, thereby ensuring the weighing accuracy and facilitating the replacement and tension adjustment of the belt 4.

[0082] A discharging slide plate 6 is also provided between the weight transmission member 1 and the right roller 9. The top of the discharging slide plate 6 is a smooth plane. The top plane of the discharging slide plate 6 is parallel to the sliding contact surface 14. The top plane of the discharging slide plate 6 is in sliding contact with the upper belt between the shafts. The top plane of the discharging slide plate 6 is not higher than the sliding contact surface 14. The distance between the rightmost end point where the sliding contact surface 14 contacts the upper belt between the shafts and the leftmost contact point between the upper belt between the shafts and the discharging slide plate 6 is CC. The length of CC needs to ensure that: 57.3×h<CC<WC / 2. The discharging slide plate 6 has the same cross-sectional shape as the weight transmission member 1. In this way, the object 7 to be weighed can smoothly cross from the sliding contact surface 14 to the discharging slide plate 6 when being supported by the belt 4, and will not bring a reaction impact to the weighing sensor 2, which can greatly improve the weighing accuracy and adapt to the weighing of high-speed objects. The discharge slide 6 is rigidly connected to the base, so that the relative positions of the discharge slide 6, the base 3, the weighing sensor 2, and the weight conductor 1 are fixed. When the position of the belt 4 of the belt conveyor mechanism relative to the weight conductor 1 is adjusted, the relative position of the discharge slide 6 and the sliding contact surface 14 will not be changed, thereby ensuring the weighing accuracy and facilitating the replacement and tension adjustment of the belt 4.

[0083] The material-adjusting slide plate 5 and the material-discharging slide plate 6 have the same cross-sectional shape as the weight-conducting member 1 , and can be detached, assembled, and fixed from the interval between the two parallel belts 4 .

[0084] The test conditions are the same as those in Example 4, SC=CC=20mm, the length of the contact portion between the material-following slide 5 and the belt 4 is 90mm, and the length of the contact portion between the material-discharging slide 6 and the belt 4 is 90mm. Since the object 7 to be weighed slides more smoothly when it goes up to and leaves the sliding contact surface 14, the actual weighing accuracy of this solution reaches 0.18g, which greatly improves the weighing accuracy compared with the prior art, and the effect is also greatly improved compared with Example 4.

[0085] When the test speed is reduced to 60 boxes / min and the speed of belt 4 is 15 m / min, the weighing accuracy of this solution reaches 0.04g, which is also better than the existing technology. At the same test speed and belt speed, the accuracy of the existing belt checkweigher is 0.06g.

[0086] Alternatively, the top planes of the material following slide plate 5 and the material discharging slide plate 6 may be coplanar with the sliding contact surface 14 .

[0087] Example 6, skateboard checkweigher, see Figure 4, the same as Example 5 is not repeated here, the difference is that the top plane of the material sliding plate 5 is slightly inclined to the upper right relative to the sliding contact surface 14 and the angle A is less than 10°, the linear speed of the belt 4 is V, g is the local gravity acceleration, the vertical distance from the leftmost contact point of the sliding contact surface 14 and the belt between the shaft to the top plane of the material sliding plate 5 is ZJ, ZJ>0.5×g×SC×SC / (V×V), so that the object 7 to be weighed can be smoothly moved from the top plane of the material sliding plate 5 to the sliding contact surface 14, and the bottom right edge of the object 7 to be weighed is approximately thrown out by inertia and finally falls on the sliding contact surface 14, instead of falling to the left of the left edge of the sliding contact surface 141 after being thrown, and the weighing sensor 2 under the weight conducting member 1 will not be disturbed due to the impact between the object 7 to be weighed and the left edge of the weight conducting member 1;

[0088] The top plane of the discharge slide 6 is slightly inclined to the lower right relative to the sliding contact surface 14, and the angle B between them is less than 10°. The vertical distance from the leftmost contact point of the belt between the discharge slide 6 and the shaft to the sliding contact surface 14 is YJ, and YJ>0.5×g×CC×CC / (V×V). In this way, the object 7 to be weighed can be smoothly moved from the sliding contact surface 14 to the top plane of the discharge slide 6, and the object 7 to be weighed will not cause weighing accuracy error due to the reaction of the weighing sensor 2 under the weight transmission part 1 after the impact with the left edge of the discharge slide 6.

[0089] The same test conditions as in Example 5, belt speed 75 m / min, 400 boxes per minute, A=B=5°, ZJ=YJ=1.6 mm, the weighing accuracy of this solution reached 0.16 g, which is much higher than the prior art. At the same time, the adjustment of the material slide 5 and the material discharging slide 6 relative to the weight transmission member 1 becomes very easy and simple, and there is no need to strictly control the parallelism and height difference between them. Since the object 7 to be weighed is more stable when it goes onto the sliding contact surface 14 and moves out of the sliding contact surface 14, the accuracy is higher and more stable than that of Example 5, and there will be no situation where the lower right corner of the object 7 to be weighed impacts the weight transmission member 1 or the lower right edge of the material discharging slide 6 due to the uneven bottom surface. This solution is easy to install and adjust, has higher accuracy, and is more adaptable.

[0090] Embodiment 7, skateboard checkweigher, is similar to embodiment 1 and is not described in detail. The difference is that the belt conveyor is a multi-roller structure, and includes a third roller below the plane where the left roller 8 and the right roller 9 are located. There is enough space between the belt and the third roller to install the weight transmission part 1 and the weighing sensor 2.

[0091] Example 8, skateboard checkweigher, see Figure 5, the same points as those in Example 2 or Example 4 are not repeated here, except that the weighing sensor 2 is interspersed between the two parallel belts 4, and the base 3 is arranged outside the two belts 4, which greatly facilitates the installation and connection between the weight transmission member 1 and the weighing sensor 2 and the base 3, and the installation, fixing or removal of the weight transmission member 1 and the weighing sensor 2 can be carried out in the gap between the two parallel belts 4. The weight transmission member 1 and the weighing sensor 2 are connected by a fastener 11.

[0092] Example 9, a skateboard checkweigher, is similar to Example 3 or Example 4 and is not described in detail. Figure 5 The cross section of the weight transmission member 1 perpendicular to the running direction of the belt 4 is a "concave" structure, and protrusions are arranged upward on both sides of the weight transmission member 1; the upper surfaces of the two protrusions are sliding contact surfaces 14; the width of the sliding contact surface 14 is less than or equal to the width of the belt 4 that is in sliding contact with it, and the height of the upper surface of the middle part of the weight transmission member 1 is lower than the long strip-shaped smooth planes on both sides, which not only ensures that the weight transmission member 1 does not hinder the movement of the object 7 to be weighed on the belt 4, but also ensures that the upper surface of the fastener 11 connecting the weight transmission member 1 and the weighing sensor cannot hinder the movement of the object 7 to be weighed. The belt 4 sliding on the sliding contact surface 14 supports the object 7 to be weighed to move.

[0093] The weight conducting member 1 with a concave center portion can significantly reduce the requirement of the slide plate checkweigher for the flatness of the bottom surface of the object 7 to be weighed.

[0094] Example 10, the same as Example 9 will not be repeated, the difference is that Figure 6 and 7 , skateboard checkweigher, the "concave" structure of the weight transmission member 1 and the protrusion therein are formed by bending a whole plate, and the bending line is parallel to the running direction of the belt 4.

[0095] Example 11, the same as Example 9 will not be repeated, the difference is that Figure 8 and 9 A skateboard checkweigher, the "concave" structure of the weight transmission member 1 includes a "concave" frame 12 made of lightweight material and a hard guide rail 13 with a smooth upper surface fixedly connected to the protrusions on the two sides of the "concave" frame 12, the upper surface of the hard guide rail is a sliding contact surface 14, the length direction of the hard guide rail 13 is consistent with the running direction of the belt 4, so that the weight transmission member 1 is both light and wear-resistant, the natural frequency of the scale platform to the weighing sensor 2 is very high, and it can be suitable for high-speed weighing.

[0096] Example 12, skateboard checkweigher, the same as Example 1 is not repeated, the difference is that a belt conveyor for rejecting unqualified objects is connected after the right roller 9, and two pneumatic nozzles are arranged on the belt conveyor for rejection, each air nozzle corresponds to a solenoid valve, and the two pneumatic nozzles point to the same direction and position, in order to adapt to the situation that the weight of multiple high-speed weighed objects is continuously unqualified, and the solenoid valve connected to one air jet nozzle cannot continuously and strongly blow air, and the objects can be continuously and strongly blown by the alternating action of the two air jet nozzles and the corresponding solenoid valves. .

Claims

1. A skateboard checkweigher, comprising a weight transmission member, a weighing sensor, and a smooth sliding contact surface on the top of the weight transmission member, wherein the sliding contact surface is a rectangular plane and is perpendicular to the load-bearing direction of the weighing sensor, and wherein: The weight transmission element is rigidly connected to the bearing end of the weighing sensor, and also includes a belt conveyor running along the material conveying direction, the belt conveyor includes a belt, and there is a roller shaft on the left and right of the upper part of the belt conveyor, which are respectively a left roller shaft and a right roller shaft, and the belt passes through the left roller shaft and the right roller shaft, and the part of the belt located between the upper vertex of the left roller shaft and the upper vertex of the right roller shaft is called the inter-axis upper belt, the weight transmission element is located between the left roller shaft and the right roller shaft, and the sliding contact surface is in sliding contact with a part of the lower surface of the inter-axis upper belt, the length of the object to be weighed along the running direction of the belt is WC, the length of the sliding contact surface along the running direction of the belt is BC, BC is greater than WC, and the axes of the left roller shaft and the right roller shaft are parallel to each other and are both parallel to the sliding contact surface; The distance between the vertex of the left roller section and the leftmost contact point between the upper belt and the sliding contact surface between the shafts is ZC. When the object to be weighed is directly pressed on the weighing sensor without the upper belt between the shafts, the downward displacement of the load-bearing end of the weighing sensor is h. The length of ZC must be guaranteed to be: 57.3×h<ZC<WC / 2; the distance between the rightmost contact point between the upper belt and the sliding contact surface between the shafts and the vertex of the right roller is YC. YC must be guaranteed to be: 57.3×h<YC<WC / 2.

2. The skateboard checkweigher according to claim 1, characterized in that The belt conveyor consists of two independent and parallel belts.

3. The skateboard checkweigher according to claim 1, characterized in that: The weight transmission element has two independent sliding contact surfaces of the same shape and size, the long side of each sliding contact surface is arranged along the running direction of the belt, and the height of other parts of the weight transmission element outside the two sliding contact surfaces is lower than that of the two sliding contact surfaces.

4. The skateboard checkweigher according to claim 1, characterized in that: The weight conductor has two independent sliding contact surfaces of the same shape and size, the long side of each sliding contact surface is arranged along the running direction of the belt, and the height of other parts of the weight conductor located outside the two sliding contact surfaces is lower than the height of the two sliding contact surfaces; it also includes two independent and parallel belts; the two belts are in sliding contact with the corresponding sliding contact surfaces respectively.

5. The skateboard checkweigher according to claim 1, characterized in that: The belt conveyor is a multi-roller structure, and includes a third roller below the plane where the left roller and the right roller are located. There is enough space between the belt and the third roller to install a weight transmission component and a weighing sensor.

6. The skateboard checkweigher according to claim 2 or 4, characterized in that: The weighing sensor is interlaced between two parallel belts, the base is arranged outside the two belts, and the weight transmission element is tightly connected with the weighing sensor.

7. The skateboard checkweigher according to claim 3 or 4, characterized in that: The cross section of the weight conductor perpendicular to the running direction of the belt is a "concave" structure, and protrusions are set upward on both sides of the weight conductor; the upper surfaces of the two protrusions are sliding contact surfaces; the width of the sliding contact surface is less than or equal to the width of the belt in sliding contact with it, and the upper surface height of the middle part of the weight conductor is lower than the long smooth planes on both sides.

8. The skateboard checkweigher according to claim 7, characterized in that: The "concave" structure of the weight transmission part and the protrusions therein are formed by bending a whole plate, and the bending line is parallel to the running direction of the belt.

9. The skateboard checkweigher according to claim 3 or 4, characterized in that: The cross section of the weight conductor perpendicular to the running direction of the belt is a "concave" structure, and protrusions are arranged upward on both sides of the weight conductor; the "concave" structure of the weight conductor includes a "concave" frame made of lightweight material and a hard guide rail with a smooth upper surface fixedly connected to the protrusions on the two side surfaces of the "concave" frame, the length direction of the hard guide rail is consistent with the running direction of the belt, and the upper surface of the hard guide rail is the sliding contact surface.

10. The skateboard checkweigher according to claim 1, characterized in that A belt conveyor is connected behind the right roller to remove unqualified objects. Two pneumatic nozzles are overlapped and arranged on the belt conveyor for removal. Each air nozzle corresponds to a solenoid valve, and the two pneumatic nozzles point to the same direction and position.

11. A skateboard checkweigher, comprising a weight transmission element, a weighing sensor, and a smooth sliding contact surface on the top of the weight transmission element, the sliding contact surface being a rectangular plane and perpendicular to the load-bearing direction of the weighing sensor, characterized in that: The weight transmission element is rigidly connected to the load-bearing end of the weighing sensor, and also includes a belt conveyor device running along the material conveying direction. The belt conveyor device includes a belt. There is a roller on the left and right of the upper part of the belt conveyor device, which are respectively a left roller and a right roller. The belt passes through the left roller and the right roller. The part of the belt between the upper vertex of the left roller and the upper vertex of the right roller is called the upper belt between the axes. The weight transmission element is located between the left roller and the right roller, and the sliding contact surface is in sliding contact with a part of the lower surface of the upper belt between the axes. The length of the object to be weighed along the running direction of the belt is WC, and the length of the sliding contact surface along the running direction of the belt is BC, which is greater than WC. The axes of the left roller and the right roller are parallel to each other and are parallel to the sliding contact surface. A material-smoothing slide plate is also provided between the left roller and the sliding contact surface. The top of the material-sliding slide is a smooth plane. The top plane of the material-sliding slide is coplanar or parallel to the sliding contact surface. The top plane of the material-sliding slide is in sliding contact with the belt between the shafts. The top plane of the material-sliding slide is not lower than the sliding contact surface. The distance between the rightmost end point of the material-sliding slide in contact with the belt between the shafts and the leftmost contact point between the belt between the shafts and the sliding contact surface is SC. The SC length must meet the following conditions: 57.3×h<SC<WC / 2.

12. A skateboard checkweigher, comprising a weight transmission element, a weighing sensor, and a smooth sliding contact surface on the top of the weight transmission element, the sliding contact surface being a rectangular plane and perpendicular to the load-bearing direction of the weighing sensor, characterized in that: The weight transmission element is rigidly connected to the load-bearing end of the weighing sensor, and also includes a belt conveyor running along the material conveying direction. The belt conveyor includes a belt. There is a roller on the left and right of the upper part of the belt conveyor, which are the left roller and the right roller respectively. The belt passes through the left roller and the right roller. The part of the belt between the upper vertex of the left roller and the upper vertex of the right roller is called the upper belt between the axes. The weight transmission element is located between the left roller and the right roller, and the sliding contact surface is in sliding contact with a part of the lower surface of the upper belt between the axes. The length of the object to be weighed along the running direction of the belt is WC, and the sliding contact surface along the running direction of the belt is The length is BC, BC is greater than WC, the axes of the left roller and the right roller are parallel to each other and are parallel to the sliding contact surface; a discharging slide plate is also arranged between the weight transmission part and the right roller, the top of the discharging slide plate is a smooth plane, the top plane of the discharging slide plate is coplanar or parallel to the sliding contact surface, the top plane of the discharging slide plate is in sliding contact with the upper belt between the shafts, the top plane of the discharging slide plate is not higher than the sliding contact surface, the distance between the rightmost end point where the sliding contact surface contacts the upper belt between the shafts and the leftmost contact point between the upper belt between the shafts and the discharging slide plate is CC, and the length of CC needs to meet the following conditions: 57.3×h<CC<WC / 2.

13. A skateboard checkweigher, comprising a weight transmission element, a weighing sensor, and a smooth sliding contact surface on the top of the weight transmission element, the sliding contact surface being a rectangular plane and perpendicular to the load-bearing direction of the weighing sensor, characterized in that: The weight transmission element is rigidly connected to the load-bearing end of the weighing sensor, and also includes a belt conveyor device running along the material conveying direction. The belt conveyor device includes a belt. There is a roller on the left and right of the upper part of the belt conveyor device, which are the left roller and the right roller respectively. The belt passes through the left roller and the right roller. The part of the belt between the upper vertex of the left roller and the upper vertex of the right roller is called the upper belt between the axes. The weight transmission element is located between the left roller and the right roller, and the sliding contact surface is in sliding contact with a part of the lower surface of the upper belt between the axes. The length of the object to be weighed along the running direction of the belt is WC, and the length of the sliding contact surface along the running direction of the belt is BC, BC is greater than WC, and the axes of the left roller and the right roller are parallel to each other and are both parallel to the sliding contact surface ; A material-sliding slide is also provided between the left roller and the sliding contact surface. The top of the material-sliding slide is a smooth plane. The top plane of the material-sliding slide is in sliding contact with the upper belt between the shafts. The distance between the rightmost end point of the material-sliding slide in contact with the upper belt between the shafts and the leftmost contact point between the upper belt between the shafts and the sliding contact surface is SC, and the SC length must meet the following conditions: 57.3×h<SC<WC / 2; the top plane of the material-sliding slide is slightly inclined toward the upper right relative to the sliding contact surface and the angle A between them is less than 10°, the linear speed of the belt is V, g is the local acceleration of gravity, and the vertical distance from the leftmost contact point between the sliding contact surface and the upper belt between the shafts to the top plane of the material-sliding slide is ZJ, ZJ>0.5×g×SC×SC / (V×V).

14. A skateboard checkweigher, comprising a weight transmission element, a weighing sensor, and a smooth sliding contact surface on the top of the weight transmission element, the sliding contact surface being a rectangular plane and perpendicular to the load-bearing direction of the weighing sensor, characterized in that: The weight transmission element is rigidly connected to the load-bearing end of the weighing sensor, and also includes a belt conveyor device running along the material conveying direction. The belt conveyor device includes a belt. There is a roller on the left and right of the upper part of the belt conveyor device, which are the left roller and the right roller respectively. The belt passes through the left roller and the right roller. The part of the belt between the upper vertex of the left roller and the upper vertex of the right roller is called the upper belt between the axes. The weight transmission element is located between the left roller and the right roller, and the sliding contact surface is in sliding contact with a part of the lower surface of the upper belt between the axes. The length of the object to be weighed along the running direction of the belt is WC, and the length of the sliding contact surface along the running direction of the belt is BC. BC is greater than WC, and the axis of the left roller and the right roller They are parallel to each other and to the sliding contact surface; a discharging slide plate is also arranged between the weight transmission part and the right roller, and the top of the discharging slide plate is a smooth plane, and the top plane of the discharging slide plate is in sliding contact with the upper belt between the shafts, and the distance between the rightmost end point where the sliding contact surface contacts the upper belt between the shafts and the leftmost contact point between the upper belt between the shafts and the discharging slide plate is CC, and the length of CC needs to ensure: 57.3×h<CC<WC / 2; the top plane of the discharging slide plate is slightly inclined toward the lower right relative to the sliding contact surface and the mutual angle B is less than 10°, and the vertical distance between the leftmost contact point between the discharging slide plate and the upper belt between the shafts and the sliding contact surface is YJ, YJ>0.5×g×CC×CC / (V×V).

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