Device and method for detecting cohesiveness of gypsum board covering paper and core material

Abstract

The invention relates to the field of a device and a method for detecting cohesiveness of plasterboard covering paper and a core material. The device comprises a base, a stand column, an upper clamp, an adjustable horizontal electric lifting platform, a universal bearing platform, a force measuring device and a lower clamp, a force measuring device is placed on an adjustable horizontal electric lifting platform through a universal bearing platform, one end of an upper clamp is locked on a stand column through a locking bolt, the stand column is vertically fixed to a base, the other end of the upper clamp is provided with a chuck capable of clamping a test piece, and the included angle between the clamping face of the chuck and the vertical stand column is 45 degrees; the upper end of the test piece is fixed in the upper clamp, the lower end of the test piece is clamped in the lower clamp, a hanging ring is arranged at the bottom of the lower clamp, the force measuring device is connected through the hanging ring of the lower clamp, the adjustable horizontal electric lifting platform is started to control the force measuring device to descend at a certain speed, and a spring in the force measuring device is compressed; the elastic force is applied to the test piece through the connecting rod and the lower clamp, the load on the test piece is gradually increased along with the descending of the force measuring device until the surface protecting paper is torn off, and the maximum force value during tearing damage is recorded.

Description

Technical Field

[0001] The invention relates to the field of construction engineering material detection, and in particular to a device and method for detecting the adhesion between gypsum board facing paper and core material. Background Art

[0002] Gypsum board is an auxiliary material widely used in interior decoration construction. It is composed of face paper and gypsum core material. The face paper surface is usually pasted, puttyed, painted and other finishing constructions. Therefore, it is necessary to have a certain bonding strength between the face paper and the gypsum core material to prevent the face paper and the finishing layer material from falling off the gypsum core material.

[0003] The national standard GB / T 9775-2008 / 5.9 puts forward technical requirements for the adhesion between the face paper and the core material, that is, the face paper and the core material should not peel off under the test load.

[0004] At present, the main technical method for testing the adhesion between the gypsum board face paper and the core material is: prepare the gypsum board into a 120*50mm strip specimen, cut a slit on one side at 20mm from one end of the longitudinal direction, and the slit does not penetrate through, and the face paper on the other side remains intact. Fix the specimen in the upper fixture chuck of the tester, so that the specimen surface is at a 45° angle to the vertical plane, and fix the lower fixture at 20mm from the corresponding end of the specimen in the longitudinal direction, and gradually increase the load weight until the face paper is torn off. Record the adhesion between the face paper and the core material of each board.

[0005] 1. The maximum load applied to the specimen is 3kg; 2. The load is applied gradually; 3. During the application of load, the specimen cut should not be subjected to horizontal force.

[0006] The invention patent application with document number CN110836849A discloses a gypsum board core material and facing paper bonding tester. The technical solution mainly uses weights and scales as loads, and loads the test piece by manual mounting.

[0007] The invention patent application with document number CN108519327A discloses a reinforcement clamp, an adhesion tester and an adhesion detection method. The technical solution mentions a reinforcement clamp, and the loading method of the technical solution is: gradually adding weights on the weight plate to tear the face paper off the core material.

[0008] The above two loading methods have different defects: 1. When mounting the weight and the manual combination weight, a downward impact force will be generated when the mounting is released at one time, which does not meet the test requirements of gradually increasing the load. In addition, the impact force can easily destroy the specimen instantly, thus leading to misjudgment of the results.

[0009] 2. Combine the weights and weights in advance to set the load, and slowly release the load. Since the load is gradually applied through manual control, the loading rate is uneven and difficult to control. It is also impossible to reproduce the detection process.

[0010] 3. In both schemes, during the loading process, the specimens will be subjected to horizontal forces and destroyed prematurely due to weight swing, operator hand shaking, etc. Summary of the invention

[0011] The purpose of the present invention is to solve the defects of the above-mentioned method for detecting the adhesion between the facing paper of gypsum board and the core material, and to provide a loading device and a loading method for detecting the adhesion between the facing paper of gypsum board and the core material, so that the detection process is more in line with standard requirements.

[0012] In order to achieve the above purpose, the present invention adopts the following technical solutions: A device for detecting the adhesion between the facing paper and the core material of a gypsum board is composed of a base, a column, an upper clamp, an adjustable horizontal electric lifting platform, a universal bearing platform, a force measuring device, and a lower clamp; The column is vertically mounted on the base, and the upper fixture can move up and down on the column. One end is provided with a locking bolt that can be locked on the column, and the other end is provided with a clamp that can hold the test piece. The clamping surface of the upper fixture clamp is at an angle of 45° with the vertical column. The upper end of the test piece is fixed in the upper fixture of the tester, and the lower end of the test piece is clamped in the lower fixture, and a lifting ring is provided at the bottom of the lower fixture; The adjustable level electric lifting platform is composed of a base and an electric lifting platform; wherein the electric lifting platform is driven by a motor to control the extension and contraction of the scissor brace by a screw rod of a moving part to realize the lifting and lowering of the platform, and is fixed on the base; the base is composed of three horizontal adjustment bolts distributed in a triangle, a metal plate, and a lower level bubble, and is placed on the base platform; The universal bearing platform is composed of a bottom plate, a top plate, a steel ball, and an upper level bubble, and is fixed on the top of the adjustable horizontal electric lifting platform.

[0013] The force measuring device is essentially a weight with a force measuring function. The main body is cylindrical, and its mass and size will be further described. It is made of metal, and a non-slip rubber pad is provided on the bottom. A through hole is provided in the center of the cylindrical main body, and a rib is provided at the upper end of the through hole; a spring is provided in the through hole, and the upper end of the spring supports the rib of the through hole, and the lower end of the spring supports a cylindrical slider that can slide up and down in the through hole. The slider is connected to a connecting rod, and the connecting rod passes between the ribs of the through hole of the cylindrical main body. A hook is provided at the upper end of the connecting rod, which can be connected to the lower clamp; Two vertical steel columns are provided on the top surface of the cylindrical body, one of which is etched with a scale related to the spring stiffness coefficient. An active pointer and a passive pointer are provided on the connecting rod. The active pointer is a metal ring with two wings, and a screw hole is provided on its side. A top screw is provided in the screw hole. The active pointer can be locked or unlocked with the connecting rod by tightening or loosening the top screw. Magnets are provided at both ends of the passive pointer, and the magnets are arranged on the opposite side of the sliding surface of the passive pointer. The passive pointer is connected to the two steel columns through the magnetic force of the magnet and can slide up and down along the surface of the steel column.

[0014] Furthermore, the moving parts, the motor, the lead screw and the scissor brace are protected by an accordion cover.

[0015] Furthermore, the bottom plate and top plate are rigid and square, with enclosures set all around, wherein the upper surface of the bottom plate and the lower surface of the top plate are smooth and flat, the top plate is slightly larger than the bottom plate and completely covers the bottom plate, and a level bubble is provided on the outer side of the enclosure at the outer edge of the top plate to display the horizontal state of the top plate.

[0016] Furthermore, the steel balls are evenly arranged on the upper surface of the bottom plate, the lower surface of the top plate and the space formed by the baffle, and can roll freely. The diameter of the steel balls is greater than the height of the bottom plate enclosure, and the number of arranged steel balls is controlled according to the diameter-to-pitch ratio.

[0017] Furthermore, the diameter-to-distance ratio is λ=n0.5*d / b, wherein b is the side length of the rigid base plate, d is the diameter of the steel ball, n is the number of steel balls, the diameter of the steel ball can be selected to be 4-7 mm, and λ is controlled between 0.3-0.4.

[0018] Furthermore, the passive pointer is made of polytetrafluoroethylene, and the friction between the passive pointer and the steel column under the action of the magnetic steel can offset its own weight so that the passive pointer can be fixed at any height of the steel column without sliding down.

[0019] Furthermore, the scale on the steel column is related to the spring stiffness coefficient, the scale spacing is 1 mm / grid, the indication is 1 N / grid, the total length is 35 grids, and the measuring range is m-35 N, where m is the total mass of the lower clamp, connecting rod, active pointer, passive pointer, spring, and slider.

[0020] Furthermore, the upper clamp chuck and the lower clamp are both C-shaped and made of metal. A through hole with an internal thread is provided in the middle of the outer frame. A movable slider is provided in the middle of the outer frame. The slider is connected to the outer frame through a screw. The screw is rotated clockwise or counterclockwise to drive the slider forward or backward to clamp or loosen the specimen. Furthermore, the cylindrical body of the force measuring device has a diameter of 100 mm, a height of 55 mm, a central through hole diameter of 21 mm, and a mass of approximately 3.14*(10 2 -2.1 2) / 4*5.5*7.85=3240g. The spring has a diameter of 10mm and a stiffness coefficient of 1N / mm. The slider has a diameter of 20mm and a height of 10mm and is made of metal. The connecting rod has a diameter of 5mm and is made of metal. The upper end is provided with a hook and the lower end is connected to the slider by a thread. How it works

[0021] The force measuring device in this scheme is placed on an adjustable horizontal electric lifting platform through a universal support platform. One end of the upper clamp is locked on the column by a locking bolt and can be moved up and down by adjusting the bolt. The column is vertically fixed on the base, and the other end is provided with a chuck that can hold the specimen. The clamping surface of the upper clamp chuck forms a 45° angle with the vertical column; the upper end of the specimen is fixed in the upper clamp of the tester, and the lower end of the specimen is clamped in the lower clamp, and a lifting ring is provided at the bottom of the lower clamp; the force measuring device is connected to the lifting ring of the lower clamp, and the adjustable horizontal electric lifting platform is started to control the descent of the force measuring device at a certain rate. The spring in the force measuring device is compressed, and its elastic force is applied to the specimen through the connecting rod and the lower clamp. As the force measuring device descends, the load on the specimen gradually increases until the specimen face paper is torn off, and the maximum force value at the time of tearing failure is recorded. Beneficial Effects

[0022] The technical solution of the present invention uses an electric lifting platform to control the height of the force measuring device at a certain speed to achieve slow application of the load, and the loading process of the load is regular and reproducible. The universal bearing platform is used to allow the force measuring device to move freely in the horizontal upward direction with the deformation of the test piece, so as to avoid the test piece being affected by the horizontal force during the loading process. This technical solution effectively makes up for the defects existing in the existing technical solution, improves the accuracy of the detection, and makes the detection process more in line with the standard requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is the overall structural diagram of the present invention; Figure 2 This is an example of the use of the present invention in a gypsum board core and face paper bonding instrument; Figure 3 It is a structural diagram of the adjustable horizontal electric lifting platform of the present invention; Figure 4 This is an exploded view of the universal bearing structure of the present invention; Figure 5 It is a structural diagram of the force measuring device of the present invention; Figure 6 is a cross-sectional view of a force measuring device of the present invention; Figure 7 It is the structural diagram of the active pointer and the passive pointer of the present invention; In the figure: 1. Test piece, 2. Upper fixture, 3. Lower fixture, 4. Base, 5. Column, 6. Adjustable horizontal electric lifting platform, 6-1. Base, 6-2. Horizontal adjustment bolt, 6-3. Lower level bubble, 6-4. Electric lifting platform, 7. Universal support, 7-1. Bottom plate, 7-2. Top plate, 7-3. Steel ball, 7-4. Upper level bubble, 7-5. Enclosure, 8. Force measuring device, 8-1. Cylindrical body, 8-2. Spring, 8-3. Slider, 8-4. Connecting rod, 8-5. Steel column, 8-6. Steel column with scale, 8-7. Active pointer, 8-8. Passive pointer, 8-9. Side rib, 9. Magnetic steel, 10. Top screw. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical solutions and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the present invention.

[0025] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the embodiments of the present invention.

[0026] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances. Example 1

[0027] Combination Figure 1-7 It can be seen that a loading device for testing the adhesion between the facing paper and the core material of a gypsum board comprises a base (4), a column (5), an upper clamp (2), an adjustable horizontal electric lifting platform (6), a universal support platform (7), a force measuring device (8), and a lower clamp (3); The column (5) is vertically mounted on the base (4); the upper clamp (2) can move up and down on the column (5); one end is provided with a locking bolt which can be locked on the column (5); the other end is provided with a clamping head which can hold the test piece (1); the clamping surface of the clamping head of the upper clamp (2) forms an angle of 45° with the vertical column (5); The upper end of the test piece (1) is fixed in an upper fixture (2) of the tester, and the lower end of the test piece (1) is clamped in a lower fixture (3), and a lifting ring is provided at the bottom of the lower fixture (3); The adjustable horizontal electric lifting platform (6) is composed of a base (6-1) and an electric lifting platform (6-4); wherein the electric lifting platform (6-4) is driven by a motor to control the extension and contraction of the scissor brace to achieve the lifting of the platform, and is fixed on the base (6-1); the base (6-1) is composed of three horizontal adjustment bolts (6-2) distributed in a triangle, a metal plate, and a lower level bubble (6-3), and is placed on the base (4) platform; The universal support platform (7) is composed of a bottom plate (7-1), a top plate (7-2), a steel ball (7-3), and an upper level bubble (7-4), and is fixed to the top of the adjustable horizontal electric lifting platform (6).

[0028] The force measuring device (8) is essentially a weight with a force measuring function, and its cylindrical body (8-1) is cylindrical, and its mass and size will be further described. It is made of metal, and a non-slip rubber pad is provided on the bottom surface. A through hole is provided in the center of the cylindrical body (8-1), and a retaining edge (8-9) is provided at the upper end of the through hole; a spring (8-2) is provided in the through hole, and the upper end of the spring (8-2) supports the through hole retaining edge (8-9), and the lower end of the spring (8-2) supports a cylindrical slider (8-3) that can slide up and down in the through hole, and the slider (8-3) is connected to the connecting rod (8-4), and the connecting rod (8-4) passes through the spring (8-2) and passes through the through hole of the cylindrical body (8-1), and a hook is provided at the upper end of the connecting rod (8-4) and can be connected to the lower clamp (3); The top surface of the cylindrical body (8-1) is provided with two vertical steel columns (8-5) (8-6), one of which is etched with a scale related to the stiffness coefficient of the spring (8-2). The connecting rod (8-4) is provided with an active pointer (8-7) and a passive pointer (8-8). The active pointer (8-7) is a metal ring with two wings, and a screw hole is provided on its side. A top screw (10) is provided in the screw hole. The active pointer (8-7) can be locked or unlocked with the connecting rod (8-4) by tightening or loosening the top screw (10). Magnets (9) are provided at both ends of the passive pointer (8-8). The magnets (9) are arranged on the opposite side of the sliding surface of the passive pointer (8-8). The passive pointer (8-8) is connected to the two steel columns (8-5) (8-6) through the magnetic force of the magnets (9) and can slide up and down along the surface of the steel columns (8-5) (8-6).

[0029] Furthermore, the electric lifting platform (6-4) is a 150-type desktop electric lifting platform.

[0030] Furthermore, the moving parts, the motor, the screw rod, and the scissor-type struts are covered with accordion covers for protection; the moving parts, the motor, the screw rod, and the scissor-type struts are purchased from the market and will not be described in detail here.

[0031] Furthermore, the bottom plate (7-1) and the top plate (7-2) are rigid and square, and are surrounded by enclosures (7-5), wherein the upper surface of the bottom plate (7-1) and the lower surface of the top plate (7-2) are smooth and flat, the top plate (7-2) is slightly larger than the bottom plate (7-1) and completely covers the bottom plate (7-1), and an upper level bubble (7-4) is provided on the outer side surface of the enclosure at the outer edge of the top plate for displaying the horizontal state of the top plate (7-2).

[0032] Furthermore, the steel balls (7-3) are evenly arranged in the space formed by the upper surface of the bottom plate (7-1), the lower surface of the top plate (7-2) and the baffle plate, and can roll freely. The diameter of the steel balls (7-3) is greater than the height of the baffle (7-5) of the bottom plate (7-1), and the number of arranged steel balls (7-3) is controlled according to the diameter-to-pitch ratio.

[0033] Furthermore, the diameter-to-distance ratio is λ=n0.5*d / b, wherein b is the side length of the rigid base plate (7-1), d is the diameter of the steel ball (7-3), n is the number of the steel balls (7-3), the diameter of the steel balls (7-3) can be selected to be 4-7 mm, and λ is controlled between 0.3-0.4.

[0034] Furthermore, the outer dimension side length of the bottom plate (7-1) of the embodiment is 180 mm, the outer dimension side length of the top plate (7-2) is 200 mm, the thickness of the enclosure (7-5) is 1 mm, the height of the enclosure (7-5) is 4 mm, the diameter of the steel ball (7-3) is 6 mm, the diameter-to-spacing ratio is 0.37, and the number is 121.

[0035] Furthermore, the passive pointer (8-8) is made of polytetrafluoroethylene, and the friction between it and the steel column (8-5) (8-6) under the action of the magnetic steel (9) can offset its own weight so that the passive pointer (8-8) can be fixed at any height of the steel columns (8-5) and (8-6) without sliding down.

[0036] Furthermore, the scale on the steel column (8-6) is related to the stiffness coefficient of the spring (8-2), the scale spacing is 1 mm / grid, the indication is 1 N / grid, the total length is 35 grids, and the measuring range is m-35 N, where m is the total mass of the lower clamp (3), the connecting rod (8-4), the active pointer (8-7), the passive pointer (8-8), the spring (8-2), and the slider (8-3).

[0037] Furthermore, the clamp head of the upper clamp (2) and the lower clamp (3) are both C-shaped and made of metal. A through hole with an internal thread is provided in the middle of the outer frame. A movable metal block is provided in the middle of the outer frame. The metal block is connected to the outer frame via a screw. The screw is rotated clockwise or counterclockwise to drive the metal block forward or backward to clamp or loosen the test piece (1).

[0038] Furthermore, the cylindrical body (8-1) of the force measuring device (8) has a diameter of 100 mm, a height of 55 mm, a central through hole diameter of 21 mm, and a mass of approximately 3.14*(10 2 -2.1 2 ) / 4*5.5*7.85=3240g. The spring (8-2) has a diameter of 10mm and a stiffness coefficient of 1N / mm. The slider (8-3) has a diameter of 20mm and a height of 10mm and is made of metal. The connecting rod (8-4) has a diameter of 5mm and is made of metal. A hook is provided at the upper end and the lower end is connected to the slider (8-3) by a thread.

[0039] Furthermore, the total mass of the lower clamp (3) does not exceed 300 g. Example 2

[0040] The method for performing a loading test using the aforementioned loading device for detecting the adhesion between the facing paper and the core material of the gypsum board is specifically implemented in the following steps: S1: Before the test, the spring (8-2) is calibrated and the spring (8-2) with a stiffness coefficient within the range of 1±1%N / mm is selected; the total mass m of the lower fixture (3), the connecting rod (8-4), the active pointer (8-7), the passive pointer (8-8), the spring (8-2) and the slider (8-3) is weighed and converted into the force unit N; the force measuring device (8) is assembled and the top screw (10) of the active pointer (8-7) is loosened. At this time, the active pointer (8-7) and the connecting rod (8-4) are in an unlocked state, the force measuring device (8) is placed horizontally, and the connecting rod (8-4) is pulled by the force measuring device until the measuring device indicates a value slightly greater than m, and the position of the active pointer (8-7) is locked at the starting point of the scale by the top screw (10); the connecting rod (8-4) is continued to be pulled to confirm whether the indication of the force measuring device (8) is accurate when the indication of the measuring device is m+10N, m+20N and m+30N.

[0041] S2: During the test, the confirmed force measuring device (8) is placed on an adjustable horizontal electric lifting platform (6) through the universal support platform (7). The force measuring device (8) is connected to the lower clamp (3), and the lower clamp (3) is clamped at the lower end of the test piece (1). The test piece (1) is fixed in the upper clamp (2) of the tester. The three horizontal adjustment bolts (6-2) of the base (6-1) of the present invention are adjusted until the universal support platform (7) is in a horizontal state. The passive pointer (8-8) is installed so that its lower edge is aligned with the active pointer. The upper edge of the needle (8-7) is flush; the adjustable horizontal electric lifting platform (6) is started to slowly lower the force measuring device (8), the spring (8-2) in the force measuring device (8) is compressed, and its elastic force is applied to the test piece (1) through the connecting rod (8-4) and the lower clamp (3), the active pointer (8-7) on the connecting rod (8-4) pushes the passive pointer (8-8) to move upward relative to the steel column (8-5) (8-6) to indicate the force value, and as the force measuring device (8) descends, the load on the test piece (1) gradually increases.

[0042] According to step S2 in the above method, the adjustable horizontal electric lifting platform (6) is started to slowly lower the force measuring device (8), the spring (8-2) in the force measuring device (8) is compressed, and as the force measuring device (8) descends, the load on the test piece (1) gradually increases until the face paper of the test piece (1) is torn off; the adjustable horizontal electric lifting platform (6) is started to rise until the force measuring device (8) is unhooked from the lower clamp (3), at which time the active pointer (8-7) returns, and the passive pointer (8-8) remains in place to indicate the maximum force value occurring during the test, and the maximum force value at the time of tearing off is recorded. The value at this time is the bonding strength value between the face paper and the gypsum core material.

Claims

1. A loading device for testing the adhesion between the facing paper and the core material of a paper-faced gypsum board, comprising a base, a column, an upper clamp, an adjustable horizontal electric lifting platform, a universal bearing platform, a force measuring device, and a lower clamp; The column is vertically mounted on the base, and the upper fixture can move up and down on the column. One end is provided with a locking bolt that can be locked on the column, and the other end is provided with a clamp that can hold the test piece. The clamping surface of the upper fixture clamp is at an angle of 45° with the vertical column. The upper end of the test piece is fixed in the upper fixture of the tester, and the lower end of the test piece is clamped in the lower fixture, and a lifting ring is provided at the bottom of the lower fixture; The adjustable level electric lifting platform is composed of a base and an electric lifting platform; wherein the electric lifting platform is driven by a motor to control the extension and contraction of the scissor brace by a screw rod of a moving part to realize the lifting and lowering of the platform, and is fixed on the base; the base is composed of three bolts, a metal plate and a level bubble distributed in a triangle for adjusting the level, and is placed on the base platform; The universal support platform is composed of a bottom plate, a steel ball, and a top plate, and is fixed on the top of the adjustable horizontal electric lifting platform; The force measuring device is essentially a weight with a force measuring function. The main body is cylindrical and made of metal, and a non-slip rubber pad is provided on the bottom surface. A through hole is provided in the center of the cylindrical main body, and a rib is provided at the upper end of the through hole. A spring is provided in the through hole, and the upper end of the spring supports the rib of the through hole, and the lower end of the spring supports a cylindrical slider that can slide up and down in the through hole. The slider is connected to a connecting rod, and the connecting rod passes between the ribs of the through hole of the cylindrical main body. A hook is provided at the upper end of the connecting rod, which can be connected to the lower clamp. Two vertical steel columns are provided on the top surface of the cylindrical body, one of which is etched with a scale related to the spring stiffness coefficient. An active pointer and a passive pointer are provided on the connecting rod. The active pointer is a metal ring with two wings, and a screw hole is provided on its side. A top screw is provided in the screw hole. The active pointer can be locked or unlocked with the connecting rod by tightening or loosening the top screw. Magnets are provided at both ends of the passive pointer, and the magnets are arranged on the opposite side of the sliding surface of the passive pointer. The passive pointer is connected to the two steel columns through the magnetic force of the magnet and can slide up and down along the surface of the steel column.

2. A loading device for detecting the adhesion between the facing paper and the core material of a gypsum board according to claim 1, characterized in that: The moving parts, the motor, the lead screw and the scissor brace are protected by an accordion sleeve.

3. A loading device for detecting the adhesion between the facing paper and the core material of a gypsum board according to claim 1, characterized in that: The bottom plate and top plate are rigid and square, with enclosures set around them. The upper surface of the bottom plate and the lower surface of the top plate are smooth and flat. The top plate is slightly larger than the bottom plate and completely covers the bottom plate. An upper level bubble is provided on the outer side of the enclosure at the outer edge of the top plate to display the horizontal state of the top plate.

4. A loading device for detecting the adhesion between the facing paper and the core material of a gypsum board according to claim 1, characterized in that: The steel balls are evenly arranged on the upper surface of the bottom plate, the lower surface of the top plate and the space formed by the enclosure and can roll freely. The diameter of the steel balls is greater than the height of the bottom plate enclosure, and the number of arranged steel balls is controlled according to the diameter-to-pitch ratio.

5. A loading device for detecting the adhesion between the facing paper and the core material of a gypsum board according to claim 4, characterized in that: The diameter-to-pitch ratio is λ=n0.5*d / b, wherein b is the side length of the rigid bottom plate, d is the diameter of the steel ball, n is the number of steel balls, the diameter of the steel ball can be selected to be 4-7 mm, and λ is controlled between 0.3-0.

4.

6. A loading device for detecting the adhesion between the facing paper and the core material of a gypsum board according to claim 1, characterized in that: The passive pointer is made of polytetrafluoroethylene. Under the action of the magnetic steel, the friction between the passive pointer and the steel column can offset its own weight so that the passive pointer can be fixed at any height of the steel column without sliding down.

7. A loading device for detecting the adhesion between the facing paper and the core material of a gypsum board according to claim 1, characterized in that: The scale on the steel column is related to the spring stiffness coefficient, the scale spacing is 1mm / grid, the indication is 1N / grid, the total length is 35 grids, and the measuring range is m-35N, where m is the total mass of the lower clamp, connecting rod, active pointer, passive pointer, spring, and slider.

8. A loading device for detecting the adhesion between the facing paper and the core material of a gypsum board according to claim 1, characterized in that: The upper clamp chuck and the lower clamp are both C-shaped and made of metal. A through hole with an internal thread is provided in the middle of the outer frame. A movable slider is provided in the middle of the outer frame. The slider is connected to the outer frame through a screw. The screw is rotated clockwise or counterclockwise to drive the slider forward or backward to clamp or loosen the specimen.

9. A method for performing a loading test using the loading device for detecting the adhesion between the facing paper and the core material of a gypsum board as claimed in claims 1 to 8, wherein the specific implementation steps are as follows: S1: Before the test, calibrate the spring and select the spring with a stiffness coefficient within the range of 1±1%N / mm; weigh the total mass m of the clamp, connecting rod, active pointer, passive pointer, spring and slider and convert it into the force unit N; assemble the force measuring device and loosen the top screw of the active pointer of the force measuring device. At this time, the active pointer and the connecting rod are unlocked, and the force measuring device is placed horizontally. Use the force measuring device to pull the connecting rod until the value indicated by the measuring device is slightly greater than m, and use the top screw to lock the position of the active pointer at the starting point of the ruler; continue to pull the connecting rod, and confirm whether the indication of the force measuring device is accurate when the indication of the measuring device is m+10N, m+20N and m+30N respectively; S2: During the test, the confirmed force measuring device is placed on an adjustable horizontal electric lifting platform through a universal support platform. The force measuring device is connected to the lower clamp, which is clamped at the lower end of the specimen. The specimen is fixed in the upper clamp of the tester. The three horizontal adjustment bolts of the base in the present invention are adjusted until the universal support platform is horizontal. The passive pointer is installed so that its lower edge is flush with the upper edge of the active pointer. Weights are mounted on the force measuring device, and the adjustable horizontal electric lifting platform is started to slowly lower the force measuring device. The spring in the force measuring device is compressed, and its elastic force is applied to the specimen through the connecting rod and the lower clamp. The active pointer on the connecting rod pushes the passive pointer to move upward relative to the steel column to indicate the force value. As the force measuring device descends, the load on the specimen gradually increases.

10. The method for performing a loading test using a loading device for detecting the adhesion between the facing paper and the core material of a gypsum board according to claim 9, characterized in that: In step S2 of the method, the adjustable horizontal electric lifting platform is started to slowly descend the force measuring device, and the spring in the force measuring device is compressed. As the force measuring device descends, the load on the specimen gradually increases until the specimen face paper is torn off; the adjustable horizontal electric lifting platform is started to rise until the force measuring device is unhooked from the lower clamp, at which time the active pointer returns and the passive pointer remains in place to indicate the maximum force value occurring during the test, and the maximum force value at the time of tearing off is recorded. The value at this time is the bonding strength value between the face paper and the gypsum core material.

Images