A helmet shear force and friction force testing device

Abstract

A helmet shear force and friction force testing device comprises a frame, a loading plate, a helmet mounting mechanism, a loading mechanism and a drop hammer mechanism, wherein the frame comprises a horizontal support beam and a vertical support beam, wherein the vertical support beam is fixed to one end of the horizontal support beam, the loading plate is slidably mounted on the horizontal support beam, the helmet mounting mechanism is hinged to the other end of the horizontal support beam, the loading mechanism is mounted below the horizontal support beam and connected to the helmet mounting mechanism via a supporting rod, and the supporting rod drives the helmet mounting mechanism to move up and down. During testing, the helmet is mounted on the helmet mounting mechanism, and the position and angle of the helmet are adjusted so that any point on the outer surface of the helmet can contact the upper surface of the loading plate. This design not only facilitates the application of force to the helmet, but also enables the magnitude of the force to be intuitively known, thereby eliminating the need to apply load to the helmet via additional components, making the testing process simpler and more convenient.

Description

Technical Field

[0001] The utility model relates to the technical field of helmet quality detection, in particular to a helmet shear force and friction force testing device. Background Art

[0002] In recent years, electric bicycles have become an important means of transportation for the general public due to their economic convenience. As the number of users increases, traffic accidents caused by electric bicycles have also increased dramatically. The correct wearing of a helmet can greatly reduce the damage caused by traffic accidents. At the same time, the quality of the helmet is also one of the key factors in ensuring personal safety. However, the quality of helmets on the market varies. In order to fully adapt to the new industry application requirements of safety helmets and ensure the safety of motorcycle and electric vehicle riders, the new version of the GB811 standard in 2022 will add more testing requirements for the shear force and friction of helmets.

[0003] Therefore, a shear force and friction force testing device for a raised structure on a helmet surface has been disclosed in a Chinese patent application number: CN202223107197.8. The device specifically includes a frame, a support frame, a sliding frame, a rotating frame, a head mold and a loading frame; the support frame is a Z-shaped structure, and one end of the support frame is rotatably arranged on the frame; a telescopic cylinder for driving the support frame to flip is arranged on the frame, and the telescopic cylinder is rotatably connected to the frame; the sliding frame is slidably arranged on the support frame, and the sliding frame is clamped with the support frame; the rotating frame is rotatably arranged on the sliding frame, and the rotating frame is clamped with the sliding frame; The head mold is arranged on the rotating frame; the object carrier is slidably arranged on the frame; the object carrier is slidably connected with the head mold; a lifting assembly for driving the object carrier to move is arranged on the frame; the device is mainly used to test the surface friction of the helmet and the shear force of the raised structure on the outer surface of the helmet, so as to prevent the helmet from being subjected to excessive resistance when rubbing against the ground in the event of an accident. The greater the friction, the greater the resistance, and the more serious the injury to the rider; and to prevent the rider from being subjected to secondary injury when the helmet with raised objects rubs against the ground during an accident, because the raised objects block the forward force of the wearer's head.

[0004] According to the test standard of GB811-2022, during the test, a force of at least 400N needs to be applied to the helmet before visual testing, and this force must be measured for each test. Obviously, the test device in the above structure cannot apply such a force to the helmet, and other components need to be added to apply the load to it. Even after the load is applied, there is no way to intuitively and accurately know the magnitude of the force acting on the helmet, which will cause certain troubles to the test and affect the test process. Utility Model Content

[0005] In order to overcome the deficiencies of the prior art, the utility model provides a helmet shear force and friction force testing device.

[0006] The technical solution adopted by the utility model to solve its technical problems is:

[0007] A helmet shear force and friction force testing device comprises a frame, a loading plate, a helmet mounting mechanism, a loading mechanism and a drop hammer mechanism, wherein the frame comprises a horizontal support beam and a vertical support beam, wherein the vertical support beam is fixed to one end of the horizontal support beam, the loading plate is slidably mounted on the horizontal support beam, the helmet mounting mechanism is hinged at the other end of the horizontal support beam, the loading mechanism is mounted below the horizontal support beam and connected to the helmet mounting mechanism through a support rod, the loading mechanism drives the helmet mounting mechanism to move up and down through the support rod, and applies a normal force acting on the loading plate to the helmet during testing, the drop hammer mechanism is mounted on the vertical support beam and connected to the loading plate through a traction belt, a support plate is provided on the loading plate, a pressure sensor is provided between the support plate and the loading plate, and a display screen for displaying the load is also provided on the upper surface of the support plate.

[0008] In the utility model, the horizontal support beams are provided with two groups and are symmetrically arranged, and the inner sides of the two groups of horizontal support beams are provided with sliding grooves for sliding the loading plate, and rollers are respectively provided on both sides of the loading plate, and the rollers extend into the sliding grooves.

[0009] Furthermore, a buffer mechanism is provided at one end of the slide groove near the vertical support beam, including a buffer spring, a pressure block, a guide rod and a guide seat. One end of the buffer spring is fixed to the end of the slide groove, and the other end extends along the slide groove. The pressure block is connected to the extended end of the buffer spring. The guide rod is arranged on the inner ring of the buffer spring and one end is fixed on the pressure block, and the other end extends toward the vertical support beam and passes through the vertical support beam. The guide seat is fixed on the vertical support beam and is slidably connected to the guide rod. The end of the guide rod is provided with a thread and cooperates with a nut to limit the guide rod in the guide seat.

[0010] In the utility model, the loading mechanism includes a support seat, a driving motor, a screw rod and a slider. The support seat is supported below a horizontal support beam. The screw rod is vertically installed in the support seat and driven to rotate by the driving motor. The slider is threadedly engaged with the screw rod and is hinged to the bottom end of the support rod. The slider drives the helmet mounting mechanism to move through the support rod.

[0011] In the utility model, the drop hammer mechanism includes a guide rod vertically arranged on one side of the vertical support beam, a counterweight block slidably fitted on the guide rod and a traction machine installed on the top of the vertical support beam. The traction machine is connected to the counterweight block through a steel wire rope, one end of the traction belt is connected to the loading plate, and the other end is connected to the counterweight block from the top of the vertical support beam after passing through two sets of turning wheels. A buffer sponge is also provided at the bottom of the guide rod.

[0012] In the utility model, the helmet mounting mechanism comprises an articulated seat arranged on a horizontal support beam away from one end of a vertical support beam, a cantilever with one end hinged on the articulated seat, and a head mold component installed at the other end of the cantilever, wherein the head mold component comprises a head mold for wearing a helmet and an adjustment seat for adjusting the angle of the head mold, wherein the rotation of the head mold is connected to one end of the adjustment seat, and the other end of the adjustment seat is hinged on the cantilever.

[0013] Furthermore, the rotating axis between the head mold and the adjustment seat is perpendicular to the rotating axis between the adjustment seat and the cantilever, and the adjustment angles between the head mold and the adjustment seat and between the adjustment seat and the cantilever are both fixed by tightening the knob.

[0014] The utility model has the following advantages and beneficial effects:

[0015] When preparing for the test, install the helmet on the helmet mounting mechanism, adjust the position and angle of the helmet so that any point on the outer surface of the helmet can contact the upper surface of the loading plate, vertically press the test point on the helmet against the center of the preparation area, and then start the loading mechanism to apply a normal force on the support plate to the helmet. The display screen on the support plate displays the current load size in real time through the pressure sensor. When the load stabilizes at 400N, the test can be started. This design not only makes it convenient to apply force to the helmet, but also allows intuitive knowledge of the force size, so that there is no need to apply load to the helmet through additional components, making the test process simpler and more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The utility model is further described below in conjunction with the accompanying drawings and embodiments:

[0017] Figure 1 is a schematic diagram of a test device in this embodiment;

[0018] Figure 2 is a perspective view of the test device in this embodiment;

[0019] Figure 3 is a top view of the carrier plate of this embodiment;

[0020] Figure 4 This is a schematic diagram of the cooperation between the loading plate and the slideway in this embodiment;

[0021] Figure 5 for Figure 2 A magnified image of area A;

[0022] Figure 6 Schematic diagram of the installation of the grinding plate and the cutting block on the object carrier in this embodiment. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the embodiments of the utility model clearer, the technical solutions in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model, but the utility model is not limited to the following embodiments.

[0024] like Figures 1 to 6 As shown, this embodiment discloses a helmet shear force and friction force testing device, including a frame 1, a loading plate 2, a helmet mounting mechanism 3, a loading mechanism 4 and a drop hammer mechanism 5, the frame 1 includes a horizontal support beam 10 and a vertical support beam 11, the vertical support beam 11 is fixed to one end of the horizontal support beam 10, the loading plate 2 is slidably mounted on the horizontal support beam 10, the helmet mounting mechanism 3 is hinged at the other end of the horizontal support beam 10, the loading mechanism 4 is installed below the horizontal support beam 10 and is connected to the helmet through a support rod 12. The helmet mounting mechanism 3 is connected to the loading mechanism 4, the loading mechanism 4 drives the helmet mounting mechanism 3 to move up and down through the support rod 12 and applies a normal force acting on the helmet on the carrier plate 2 during the test. The drop hammer mechanism 5 is installed on the vertical support beam 11 and connected to the carrier plate 2 through the traction belt 53, thereby driving the carrier plate 2 to move along the horizontal support beam 10 toward the vertical support beam 11. Specifically, at least 2 / 3 of one side of the upper surface of the carrier plate 2 is set as the test area 20, and the rest of the upper surface of the carrier plate 2 is set as the preparation area 21. A frosted plate 22 and a cut block 23 are installed on the test area 20, and the cut block 23 is arranged at the edge of the side away from the preparation area 21, and the length direction of the cut block 23 is perpendicular to the moving direction of the carrier plate 2; the preparation area 21 is covered with a support plate 24, and a pressure sensor is arranged between the support plate 24 and the carrier plate 2, and a display screen 25 for displaying the load is also arranged on the upper surface of the support plate 24. When preparing for the test, the helmet is installed on the helmet mounting mechanism 3, and the position and angle of the helmet are adjusted so that any point on the outer surface of the helmet can contact the upper surface of the carrier plate 2, and the test point on the helmet is vertically pressed against the center of the preparation area 21, and then the loading mechanism 4 is started to apply a normal force on the support plate 24 to the helmet. The display screen 25 on the support plate 24 displays the size of the current load in real time through the pressure sensor. When the load is stable at 400N, the test can be started. This design is not only convenient for applying a force to the helmet, but also can intuitively know the size of the force, so that there is no need to apply a load to the helmet through additional components, making the test process simpler and more convenient.

[0025] In this embodiment, the horizontal support beams 10 are provided with two groups and are symmetrically arranged. The inner sides of the two groups of horizontal support beams 10 are provided with sliding grooves 100 for the sliding of the carrier plate 2. In order to avoid excessive friction, two groups of rollers 26 are respectively provided on both sides of the carrier plate 2. The rollers 26 extend into the sliding grooves 100. It can be determined that the diameter of the rollers 26 is smaller than the groove width of the sliding groove 100.

[0026] Furthermore, after the test is completed, the carrier plate 2 will continue to move along the slide slot 100 due to inertia. At this time, in order to avoid a violent collision when the carrier plate 2 moves to the end of the horizontal support beam 10 and damage the carrier plate 2, a buffer mechanism is provided at one end of the slide slot 100 close to the vertical support beam 11. The buffer mechanism includes a buffer spring 13, a pressure block 14, a guide rod 15 and a guide seat 16. One end of the buffer spring 13 is fixed to the end of the slide slot 100, and the other end extends along the slide slot 100. The pressure block 14 is connected to the extended end of the buffer spring 13. The guide rod 15 is arranged on the inner ring of the buffer spring 13 and one end is fixed on the pressure block 14, and the other end is extended to the vertical support beam 11. The guide seat 16 is fixed on the vertical support beam 11 and is slidably connected with the guide rod 15 so as to be guided by the guide rod 15. At the same time, the end of the guide rod 15 is provided with a thread and cooperates with a nut to limit the guide rod 15 in the guide seat 16 to prevent it from escaping. When the carrier 2 approaches the buffer mechanism, the rollers 26 on both sides of the carrier 2 compress the buffer spring 13 along the direction of the guide rod 15 through the pressure block 14, thereby converting the kinetic energy into elastic potential energy, so that the carrier 2 can be prevented from having a violent collision. Not limited to the above embodiment, a push block 27 can also be provided on the side of the carrier 2 close to the buffer mechanism, and the push block 27 extends into the slide groove 100 to contact the pressure block 14.

[0027] In this embodiment, the frosted plate 22 and the cut block 23 are both removable and installed on the test area 20. The test area 20 is provided with a mounting groove 200 for mounting the frosted plate 22 and the cut block 23. The frosted plate 22 and the cut block 23 are both provided with a mounting structure 201 and are slidably fitted in the mounting groove 200 through the mounting structure 201. During the friction force test, the cut block 23 is not needed and the cut block 23 can be removed. During the shear force test, since the rough surface of the frosted plate 22 is not needed, the frosted plate 22 can be removed and replaced with a flat plate with a smooth surface, so as to keep the height of the test area 20 consistent with the height of the preparation area 21.

[0028] Without being limited to the above embodiments, the frosted plate 22 may also be provided with a rough surface on the front side and a smooth surface on the back side, and a mounting structure 201 for fitting into the mounting groove 200 may be provided on both the front side and the back side. In this way, there is no need to prepare an additional flat plate. In order to prevent the mounting structure 201 from affecting the test, a mounting structure 201 is provided at the edge of the frosted plate 22.

[0029] In this embodiment, the loading mechanism 4 includes a support seat 40, a driving motor 41, a screw rod 42 and a slider 43. The support seat 40 is supported below the horizontal support beam 10. The screw rod 42 is vertically installed in the support seat 40 and is driven to rotate by the driving motor 41. The slider 43 is threadedly engaged on the screw rod 42 and is hinged to the bottom end of the support rod 12. When the screw rod 42 rotates, it drives the slider 43 to move up and down. The slider 43 drives the helmet mounting mechanism 3 to move through the support rod 12 to adjust the angle of the helmet.

[0030] In this embodiment, the drop hammer mechanism 5 includes a guide rod 50 vertically arranged on one side of the vertical support beam 11, a counterweight 51 slidably fitted on the guide rod 50, and a traction machine 52 installed on the top of the vertical support beam 11. The traction machine 52 is connected to the counterweight 51 through a steel wire rope, one end of the traction belt 53 is connected to the carrier plate 2, and the other end passes through two sets of changing wheels 54 and is connected to the counterweight 51 from the top of the vertical support beam 11, so that the gravitational potential energy of the counterweight 51 can be converted into kinetic energy of the carrier plate 2; preferably, a buffer sponge 55 is also provided at the bottom of the guide rod 50.

[0031] In this embodiment, the helmet mounting mechanism 3 includes an articulated seat 30 arranged on one end of the horizontal support beam 10 away from the vertical support beam 11, a cantilever 31 with one end hinged to the upper end of the articulated seat 30, and a head shape component 32 installed at the other end of the cantilever 31. The head shape component 32 includes a head mold 320 for wearing a helmet and an adjustment seat 321 for adjusting the angle of the head mold 320. The rotation of the head mold 320 is connected to one end of the adjustment seat 321, and the other end of the adjustment seat 321 is hinged to the cantilever 31. Specifically, the rotating shaft between the head mold 320 and the adjustment seat 321 is perpendicular to the rotating shaft between the adjustment seat 321 and the cantilever 31. The adjustment angles between the head mold 320 and the adjustment seat 321 and between the adjustment seat 321 and the cantilever 31 are all tightened and fixed by a knob; preferably, the upper end of the support rod 12 is hinged to the cantilever 31 at one end close to the head shape component 32.

[0032] The above contents described in this specification are merely examples of the present invention. Technicians in the technical field to which the present invention belongs can make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the contents of the present invention specification or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

Claims

1. A helmet shear force and friction force testing device, characterized in that: The invention comprises a frame (1), a loading plate (2), a helmet mounting mechanism (3), a loading mechanism (4) and a drop hammer mechanism (5), wherein the frame (1) comprises a horizontal support beam (10) and a vertical support beam (11), wherein the vertical support beam (11) is fixed to one end of the horizontal support beam (10), the loading plate (2) is slidably mounted on the horizontal support beam (10), the helmet mounting mechanism (3) is hinged to the other end of the horizontal support beam (10), and the loading mechanism (4) is mounted below the horizontal support beam (10) and connected to the helmet mounting mechanism via a support rod (12). The helmet mounting mechanism (3) is connected to the loading mechanism (4), the loading mechanism (4) drives the helmet mounting mechanism (3) to move up and down through the support rod (12), and applies a normal force acting on the loading plate (2) to the helmet during testing, the drop hammer mechanism (5) is installed on the vertical support beam (11) and connected to the loading plate (2) through a traction belt (53), a support plate (24) is provided on the loading plate (2), a pressure sensor is provided between the support plate (24) and the loading plate (2), and a display screen (25) for displaying the load is also provided on the upper surface of the support plate (24).

2. A helmet shear force and friction force testing device according to claim 1, characterized in that: The horizontal support beams (10) are provided in two groups and are symmetrically arranged. The inner sides of the two groups of horizontal support beams (10) are provided with slide grooves (100) for sliding the loading plate (2). The two sides of the loading plate (2) are respectively provided with rollers (26), and the rollers (26) extend into the slide grooves (100).

3. A helmet shear force and friction force testing device according to claim 2, characterized in that: A buffer mechanism is provided at one end of the slide groove (100) near the vertical support beam (11), comprising a buffer spring (13), a pressure block (14), a guide rod (15) and a guide seat (16); one end of the buffer spring (13) is fixed to the end of the slide groove (100), and the other end extends along the slide groove (100); the pressure block (14) is connected to the extended end of the buffer spring (13); the guide rod (15) is arranged in the inner ring of the buffer spring (13) and one end is fixed to the pressure block (14), and the other end extends in the direction of the vertical support beam (11) and passes through the vertical support beam (11); the guide seat (16) is fixed to the vertical support beam (11) and is slidably connected to the guide rod (15); the end of the guide rod (15) is provided with a thread and cooperates with a nut to limit the guide rod (15) in the guide seat (16).

4. A helmet shear force and friction force testing device according to claim 1, characterized in that: The loading mechanism (4) comprises a support seat (40), a drive motor (41), a screw rod (42) and a slider (43); the support seat (40) is supported below the horizontal support beam (10); the screw rod (42) is vertically mounted in the support seat (40) and driven to rotate by the drive motor (41); the slider (43) is threadedly engaged with the screw rod (42) and is hinged to the bottom end of the support rod (12); the slider (43) drives the helmet mounting mechanism (3) to move via the support rod (12).

5. A helmet shear force and friction force testing device according to claim 1, characterized in that: The drop hammer mechanism (5) comprises a guide rod (50) vertically arranged on one side of a vertical support beam (11), a counterweight (51) slidably fitted on the guide rod (50), and a traction machine (52) installed on the top of the vertical support beam (11); the traction machine (52) is connected to the counterweight (51) via a steel wire rope; one end of the traction belt (53) is connected to the loading plate (2); the other end of the traction belt (53) passes through two sets of direction-changing wheels (54) and is connected to the counterweight (51) from the top of the vertical support beam (11); and a buffer sponge (55) is further provided at the bottom of the guide rod (50).

6. A helmet shear force and friction force testing device according to claim 1, characterized in that: The helmet mounting mechanism (3) comprises a hinged seat (30) arranged on one end of the horizontal support beam (10) away from the vertical support beam (11), a cantilever (31) with one end hinged to the hinged seat (30), and a head mold component (32) mounted on the other end of the cantilever (31); the head mold component (32) comprises a head mold (320) for wearing a helmet and an adjustment seat (321) for adjusting the angle of the head mold (320); the head mold (320) is rotatably connected to one end of the adjustment seat (321), and the other end of the adjustment seat (321) is hinged to the cantilever (31).

7. A helmet shear force and friction force testing device according to claim 6, characterized in that: The rotation axis between the head mold (320) and the adjustment seat (321) is perpendicular to the rotation axis between the adjustment seat (321) and the cantilever (31), and the adjustment angles between the head mold (320) and the adjustment seat (321) and between the adjustment seat (321) and the cantilever (31) are both fixed by tightening a knob.

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