A pipeline bending strength detection device for water conservancy buried engineering construction

Abstract

This invention relates to the field of strength testing equipment technology, specifically a device for testing the bending strength of pipelines in underground water conservancy engineering. It includes a machine base and rollers movably mounted above the machine base. Two swing seats are symmetrically and movably arranged on the machine base, each with a sleeve rotatably mounted for clamping and fixing the pipeline to be tested. A geared motor is installed on the machine base and connected to one of the sleeves. The geared motor is also connected to a moving plate via a transmission mechanism. The moving plate is horizontally slidably positioned above the machine base. The rollers are mounted on the moving plate via a lifting assembly. This invention synchronously drives the pipeline's rotation and the moving plate's horizontal reciprocating motion via the geared motor. The rollers, under the action of the lifting assembly, continuously roll around the pipe wall. The swing seats and sleeves form a rotatable fulcrum, ensuring the pipeline maintains tangential freedom during bending, eliminating additional shear force caused by fixed clamping, and resulting in test results that more closely approximate the actual stress state of buried pipes during earthquakes and landslides.

Description

Technical Field

[0001] This invention relates to the field of strength testing equipment technology, specifically a device for testing the bending strength of pipelines in underground water conservancy engineering construction. Background Technology

[0002] With the rapid advancement of large-scale underground water conservancy projects such as integrated urban and rural water supply, large-diameter polyethylene (PE), polyvinyl chloride (PVC), and steel pipes (DN300 and above) are widely used in water transmission and distribution networks. These pipelines are subjected to multiple forces over long periods, including static loads from the overburden, dynamic loads from traffic, seismic waves, and landslide thrust. Their failure modes are primarily "bending-springback" fatigue and composite shear dislocation, rather than the single bending moment failure commonly observed in laboratory settings. Therefore, accurately determining the bending strength of buried pipelines under composite stress conditions has become a key technical aspect in ensuring the safe operation of these projects.

[0003] Existing technologies commonly employ three-point or four-point bending testing machines to test the bending strength of pipelines. A typical structure involves placing a short pipe section on a fixed support and applying vertical load through an upper pressure head until the pipe wall yields or fractures. However, this approach reveals some shortcomings when simulating underground hydraulic engineering conditions.

[0004] Traditional equipment only applies single-sided point loading to the outer wall of the pipe, failing to reproduce the circumferential constraint and reverse support of the backfill soil on the pipe. This results in measured ultimate bending moments generally exceeding the true values ​​in the soil. To fix the sample, existing clamps typically rigidly hold both ends of the pipe, forming a "fixed" boundary. When the pipe undergoes bending deformation, it cannot slip slightly along the tangential direction, generating additional shear force at the supports. This causes the test results to deviate from the pure bending state, misjudging the true bearing capacity under earthquakes and landslides. Three-point and four-point bending can only complete a certain range of local bending at once and cannot simulate the periodic circumferential stress migration caused by seismic waves or traffic vibrations, thus failing to accurately detect the fatigue life of the pipe. Summary of the Invention

[0005] The purpose of this invention is to provide a device for testing the bending strength of pipelines in underground water conservancy projects, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] A device for testing the bending strength of a pipeline in underground water conservancy engineering construction includes a machine base and rollers movably mounted above the machine base. Two swing seats are symmetrically and movably mounted on the machine base, and sleeves for clamping and fixing the pipeline to be tested are rotatably mounted on the swing seats.

[0008] A geared motor is installed on the machine base. The geared motor is connected to one of the sleeves and is used to drive the sleeve and the pipe to be tested clamped and fixed on the sleeve to rotate. The geared motor is also connected to a moving plate through a transmission mechanism. The moving plate is horizontally slidably arranged above the machine base.

[0009] The transmission mechanism is used to drive the moving plate to move horizontally and reciprocally above the machine platform via the geared motor, and the rollers are mounted on the moving plate via a lifting assembly.

[0010] The above-mentioned device for testing the bending strength of pipelines in underground water conservancy projects:

[0011] The sleeve is provided with a clamping assembly, which includes a threaded cylinder and a threaded rod.

[0012] The threaded cylinder is fixedly mounted on the sleeve along the diametrical direction, and the threaded rod is threadedly engaged with the threaded cylinder.

[0013] The above-mentioned device for testing the bending strength of pipelines in underground water conservancy projects:

[0014] One end of the threaded rod extends into the inside of the sleeve, a clamp is fixedly provided at one end of the threaded rod, and a knob is fixedly provided at the other end of the threaded rod.

[0015] The above-mentioned device for testing the bending strength of pipelines in underground water conservancy projects:

[0016] The two swing seats are rotatably mounted on the machine base via two rotating shafts, and both rotating shafts are rotatably connected to the machine base. The two swing seats are also rotatably connected to the two rotating shafts respectively.

[0017] The above-mentioned device for testing the bending strength of pipelines in underground water conservancy projects:

[0018] The geared motor is fixedly mounted on the machine base, and the output end of the geared motor is coaxially and fixedly connected to one end of one of the rotating shafts.

[0019] A bevel gear is coaxially fixed on one of the rotating shafts, and a transmission shaft is rotatably mounted on the swing base.

[0020] The above-mentioned device for testing the bending strength of pipelines in underground water conservancy projects:

[0021] A second bevel gear is coaxially fixed at one end of the drive shaft, and the second bevel gear meshes with the first bevel gear.

[0022] A first spur gear is coaxially fixed at the other end of the drive shaft, and a second spur gear that meshes with the first spur gear is coaxially fixed on the sleeve.

[0023] The above-mentioned device for testing the bending strength of pipelines in underground water conservancy projects:

[0024] The transmission mechanism includes a reciprocating component and a linkage component, wherein the reciprocating component includes a rotating rod and a fixed base;

[0025] The rotating rod is horizontally rotatable on the machine base, and the fixed seat is fixedly mounted on the movable plate.

[0026] The above-mentioned device for testing the bending strength of pipelines in underground water conservancy projects:

[0027] The fixed seat is slidably sleeved on the outer wall of the rotating rod, and the inner wall of the fixed seat is fitted with rolling balls.

[0028] The outer wall of the rotating rod is provided with an annular track along its length, and the ball bearings are also rolled and fitted into the annular track.

[0029] The above-mentioned device for testing the bending strength of pipelines in underground water conservancy projects:

[0030] The linkage component includes a transmission rod that is vertically rotatably mounted on the machine base, a No. 3 bevel gear that is coaxially fixed on the rotating shaft, and a No. 4 bevel gear that meshes with the No. 3 bevel gear that is coaxially fixed at one end of the transmission rod.

[0031] A No. 5 bevel gear is coaxially fixed at the other end of the transmission rod, and a No. 6 bevel gear that meshes with the No. 5 bevel gear is coaxially fixed on the rotating rod.

[0032] The above-mentioned device for testing the bending strength of pipelines in underground water conservancy projects:

[0033] The lifting assembly includes a sliding plate and a cylinder. The sliding plate is vertically slidably mounted on the moving plate, and the cylinder is vertically fixedly mounted on the moving plate, with the output end of the cylinder fixedly connected to the top of the moving plate.

[0034] A bracket is fixedly mounted on the movable plate, and the rollers are rotatably mounted on the bracket.

[0035] Compared with the prior art, the beneficial effects of the present invention are:

[0036] The pipeline is synchronously driven by a geared motor to rotate and the moving plate reciprocates horizontally. The rollers continuously roll around the pipe wall under the action of the lifting component, simulating the periodic bending and rebound loads of buried pipelines under complex conditions such as foundation settlement and seismic waves. The test data is closer to the real environment. The swing seat and the sleeve form a rotatable fulcrum, so that the pipeline always maintains tangential freedom during bending, eliminating the additional shear force caused by fixed clamping. The test results are closer to the real stress state of buried pipes during earthquakes and landslides. Attached Figure Description

[0037] Figure 1 A schematic diagram of the overall structure of a pipeline bending strength testing device used in underground water conservancy projects.

[0038] Figure 2 A cross-sectional view of the pendulum base, sleeve, and clamping components in a pipeline bending strength testing device used in underground water conservancy projects.

[0039] Figure 3 for Figure 2 Enlarged view of point A in the middle.

[0040] Figure 4 for Figure 2 Enlarged view of section B in the middle.

[0041] Figure 5 A partial structural diagram of a pipeline bending strength testing device used in underground water conservancy projects.

[0042] Figure 6 A cross-sectional view of the fixing seat in a pipeline bending strength testing device used in underground water conservancy projects.

[0043] Figure 7 for Figure 6 Enlarged view of point C in the middle.

[0044] Figure 8 A schematic diagram showing the disassembled rotating rod and fixed seat in a pipeline bending strength testing device used in underground water conservancy projects.

[0045] Figure 9 A schematic diagram of the overall structure of a pipeline bending strength testing device used in underground water conservancy projects, taken from another perspective.

[0046] Figure 10 for Figure 9 Enlarged view of point D in the middle.

[0047] In the diagram: 1. Machine base; 2. Roller; 3. Swing seat; 4. Sleeve; 5. Gear motor; 6. Moving plate; 7. Threaded cylinder; 8. Threaded rod; 9. Clamping plate; 10. Rotating shaft; 11. Bevel gear No. 1; 12. Drive shaft; 13. Bevel gear No. 2; 14. Spur gear No. 1; 15. Spur gear No. 2; 16. Rotating rod; 1601. Circular track; 17. Fixed seat; 18. Ball bearing; 19. Drive rod; 20. Bevel gear No. 3; 21. Bevel gear No. 4; 22. Bevel gear No. 5; 23. Bevel gear No. 6; 24. Sliding plate; 25. Cylinder; 26. Support. Detailed Implementation

[0048] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0049] Please see Figures 1-10 As an embodiment of the present invention, a pipe bending strength testing device for underground water conservancy engineering construction includes a machine base 1 and a roller 2 movably arranged above the machine base 1. Two swing seats 3 are symmetrically and movably arranged on the machine base 1, and a sleeve 4 for clamping and fixing the pipe to be tested is rotatably arranged on the swing seats 3.

[0050] The machine base 1 is equipped with a geared motor 5, which is connected to one of the sleeves 4 and is used to drive the sleeve 4 and the pipe to be tested clamped and fixed on the sleeve 4 to rotate; and the geared motor 5 is also connected to a moving plate 6 through a transmission mechanism, which is horizontally slidably disposed above the machine base 1.

[0051] The transmission mechanism is used to drive the moving plate 6 to move horizontally and reciprocally above the machine base 1 via the reduction motor 5, and the roller 2 is mounted on the moving plate 6 via a lifting assembly.

[0052] In this embodiment, the machine base 1 serves as the base of the entire device, providing rigid support for all subsequent movements; two swingable swing seats 3 are symmetrically installed on the machine base 1, and each swing seat 3 is equipped with a sleeve 4 that can rotate around its own axis; when the pipe to be tested is inserted into the sleeves 4 at both ends, the sleeve 4 forms an integral part with the pipe through the clamping mechanism, so that the pipe obtains the freedom to rotate around its axis.

[0053] The geared motor 5 is fixed on the machine base 1. Its output end can drive the sleeve 4 on one side. The sleeve 4 then drives the clamped pipe to rotate continuously. At the same time, the same output shaft of the geared motor 5 converts the rotational motion into the horizontal reciprocating motion of the moving plate 6 through the transmission mechanism. The moving plate 6 is constrained above the machine base 1 by the linear guide rail and can only move back and forth along the length of the pipe.

[0054] A lifting assembly is installed on the movable plate 6, and a roller 2 is installed on the telescopic end of the lifting assembly. The lifting assembly can push the roller 2 vertically closer to or away from the outer wall of the pipe. When the roller 2 is pressed down to contact the pipe, the rotation of the pipe and the reciprocating motion of the movable plate 6 are superimposed, so that the roller 2 generates a combined load of circumferential rolling and axial periodic bending on the pipe wall, thereby simulating the bending and rebound fatigue effect of buried pipeline under complex foundation conditions.

[0055] As a further embodiment of the present invention, the sleeve 4 is provided with a clamping assembly, the clamping assembly including a threaded cylinder 7 and a threaded rod 8;

[0056] The threaded cylinder 7 is fixedly mounted on the sleeve 4 along the diameter direction, and the threaded rod 8 is threadedly engaged with the threaded cylinder 7;

[0057] One end of the threaded rod 8 extends into the inside of the sleeve 4, a clamping plate 9 is fixedly provided at one end of the threaded rod 8, and a knob is fixedly provided at the other end of the threaded rod 8.

[0058] In this embodiment, please refer to Figure 2 and Figure 3 The threaded cylinder 7 is pre-welded to the wall of the sleeve 4 along the diameter direction. Its inner hole is machined with internal threads to form a rigid channel perpendicular to the axis of the sleeve 4. After the threaded rod 8 is screwed into the threaded cylinder 7, the two form a helical pair. When the operator turns the knob clockwise, the threaded rod 8 is fed towards the center of the sleeve 4 under the action of the helical pair, driving the front clamping plate 9 to move inward synchronously until the clamping plate 9 presses against the outer wall of the pipe to complete the clamping. When the knob is turned counterclockwise, the threaded rod 8 retracts and the clamping plate 9 is released, allowing the pipe to be tested to be quickly inserted or removed. Throughout the process, the self-locking characteristic of the threaded pair ensures that the clamping force will not loosen on its own, ensuring that the pipe always moves synchronously with the sleeve 4 during subsequent rotation and reciprocating rolling tests.

[0059] As a further embodiment of the present invention, the two swing seats 3 are rotatably mounted on the machine base 1 via two rotating shafts 10, and both rotating shafts 10 are rotatably connected to the machine base 1. The two swing seats 3 are also rotatably connected to the two rotating shafts 10 respectively.

[0060] The geared motor 5 is fixedly mounted on the machine base 1, and the output end of the geared motor 5 is coaxially and fixedly connected to one end of one of the rotating shafts 10.

[0061] A bevel gear 11 is coaxially fixed on one of the rotating shafts 10, and a transmission shaft 12 is rotatably mounted on the swing base 3;

[0062] A second bevel gear 13 is coaxially fixed at one end of the transmission shaft 12, and the second bevel gear 13 meshes with the first bevel gear 11.

[0063] A first spur gear 14 is coaxially fixed at the other end of the transmission shaft 12, and a second spur gear 15, which meshes with the first spur gear 14, is coaxially fixed on the sleeve 4.

[0064] In this embodiment, please refer to Figure 1 , Figure 4 and Figure 5 The machine base 1 is fixed, and two rotating shafts 10 are horizontally mounted on the machine base 1 through bearings, and can rotate freely around their own axes; two swing seats 3 are respectively fitted on these two rotating shafts 10, so that they can swing with the rotating shafts 10 as the fulcrum, and whether the rotating shafts 10 rotate or not does not affect the swing seats 3.

[0065] The geared motor 5 is fixed on the machine base 1, and its output end is coaxially locked with one of the rotating shafts 10. After the geared motor 5 is started, the rotating shaft 10 immediately obtains continuous rotational power.

[0066] On this rotating shaft 10, the first bevel gear 11 is coaxially fixed to the shaft 10 and rotates synchronously with the shaft 10; the first bevel gear 11 meshes with the second bevel gear 13 and transmits the rotational power to the transmission shaft 12, which is supported on the swing base 3 by bearings and can rotate relative to the swing base 3; the first spur gear 14, which is fixed to the other end, continues to transmit the power to the second spur gear 15, which is coaxially fixed to the sleeve 4, thereby driving the sleeve 4 to rotate around its own axis;

[0067] Since the sleeve 4 clamps the pipe to be tested, the pipe rotates along with the sleeve 4; at the same time, the swing seat 3 can swing around the rotating shaft 10, and the entire power transmission chain remains engaged during the swing, ensuring that the pipe can rotate continuously and smoothly at any swing angle, providing a uniform circumferential motion basis for the subsequent loading of the roller 2.

[0068] As a further embodiment of the present invention, the transmission mechanism includes a reciprocating component and a linkage component, wherein the reciprocating component includes a rotating rod 16 and a fixed seat 17.

[0069] The rotating rod 16 is horizontally rotatably mounted on the machine base 1, and the fixed base 17 is fixedly mounted on the movable plate 6;

[0070] The fixed seat 17 is slidably sleeved on the outer wall of the rotating rod 16, and the inner wall of the fixed seat 17 is fitted with rolling balls 18.

[0071] The outer wall of the rotating rod 16 is provided with an annular track 1601 along its length, and the ball bearing 18 is also rolled and embedded in the annular track 1601.

[0072] The linkage component includes a transmission rod 19 that is vertically rotatably mounted on the machine base 1, a No. 3 bevel gear 20 that is coaxially fixed on the rotating shaft 10, and a No. 4 bevel gear 21 that meshes with the No. 3 bevel gear 20 that is coaxially fixed at one end of the transmission rod 19.

[0073] A fifth bevel gear 22 is coaxially fixed at the other end of the transmission rod 19, and a sixth bevel gear 23 that meshes with the fifth bevel gear 22 is coaxially fixed on the rotating rod 16.

[0074] In this embodiment, please refer to Figure 7 , Figure 8 and Figure 10 After the geared motor 5 drives the rotating shaft 10 to rotate, the No. 3 bevel gear 20, which is coaxially fixed on the rotating shaft 10, rotates synchronously. The No. 3 bevel gear 20 meshes with the No. 4 bevel gear 21, converting the rotation around the horizontal axis into rotation around the vertical axis, and transmitting it to the vertically arranged transmission rod 19. The transmission rod 19 is supported on the machine base 1 by bearings and can rotate freely. The No. 5 bevel gear 22 at its other end meshes with the No. 6 bevel gear 23, converting the rotation around the vertical axis back to rotation around the horizontal axis, driving the rotating rod 16 to rotate continuously.

[0075] The outer wall of the rotating rod 16 is machined with a closed annular track 1601. The fixed seat 17 is fixedly connected to the moving plate 6. The fixed seat 17 has rolling balls 18 embedded in it, and the balls 18 are also embedded in the annular track 1601. When the rotating rod 16 rotates, the annular track 1601 moves in a circular motion with the rotating rod 16, thereby forcing the balls 18 to make periodic displacement along the axial direction. Since the fixed seat 17 can only slide along the horizontal linear guide rail with the moving plate 6, the axial displacement of the balls 18 directly drives the fixed seat 17 and the moving plate 6 to make horizontal reciprocating motion.

[0076] As a further embodiment of the present invention, the lifting assembly includes a sliding plate 24 and a cylinder 25. The sliding plate 24 is vertically slidably disposed on the moving plate 6, and the cylinder 25 is vertically fixedly disposed on the moving plate 6, and the output end of the cylinder 25 is fixedly connected to the top of the moving plate 6.

[0077] A bracket 26 is fixedly mounted on the movable plate 6, and the roller 2 is rotatably mounted on the bracket 26.

[0078] In this embodiment, please refer to Figure 1 and Figure 2The cylinder body of cylinder 25 is vertically fixed on the moving plate 6, and the end of its piston rod is fixedly connected to the top of the sliding plate 24. The sliding plate 24 is constrained to the side of the moving plate 6 by a vertical guide rail and can only slide up and down. When compressed air is introduced into cylinder 25, the piston rod drives the sliding plate 24 to move up and down along the guide rail. The lower end of the sliding plate 24 is equipped with a bracket 26, and the roller 2 is horizontally installed in the bracket 26 through a bearing. As the sliding plate 24 descends, the roller 2 gradually approaches and presses against the outer wall of the pipe to be tested, and immediately disengages when it rises. Thus, the extension and retraction of cylinder 25 can quickly adjust the pressing depth of the roller 2 into the pipe, realize the precise application of different bending loads, and the roller 2 can still rotate freely in the bracket 26 to ensure rolling contact and avoid sliding friction when rotating with the pipe.

[0079] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0080] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A device for testing the bending strength of pipelines in underground water conservancy engineering construction, comprising a machine base (1) and rollers (2) movably disposed above the machine base (1), characterized in that, Two swing seats (3) are symmetrically and movably arranged on the machine base (1), and a sleeve (4) for clamping and fixing the pipeline to be tested is rotatably arranged on the swing seat (3). A geared motor (5) is installed on the machine base (1). The geared motor (5) is connected to one of the sleeves (4) and is used to drive the sleeve (4) and the pipe to be tested clamped and fixed on the sleeve (4) to rotate. The geared motor (5) is also connected to a moving plate (6) through a transmission mechanism. The moving plate (6) is horizontally slidably arranged above the machine base (1). The transmission mechanism is used to drive the moving plate (6) to move horizontally and reciprocally above the machine base (1) via the geared motor (5), and the roller (2) is set on the moving plate (6) via the lifting assembly; The two swing seats (3) are rotatably mounted on the machine base (1) via two rotating shafts (10), and both rotating shafts (10) are rotatably connected to the machine base (1). The two swing seats (3) are also rotatably connected to the two rotating shafts (10). The transmission mechanism includes a reciprocating assembly and a linkage assembly. The reciprocating assembly includes a rotating rod (16) and a fixed seat (17). The rotating rod (16) is horizontally rotatably mounted on the machine base (1), and the fixed seat (17) is fixedly mounted on the moving plate (6). The fixed seat (17) is slidably sleeved on the outer wall of the rotating rod (16), and the inner wall of the fixed seat (17) is rolled and fitted with a ball (18). The outer wall of the rotating rod (16) is provided with an annular track (1601) along its length direction, and the ball (18) is also rolled and fitted in the annular track (1601). The linkage assembly includes a transmission rod (19) that is vertically rotatably mounted on the machine base (1), a No. 3 bevel gear (20) that is coaxially fixed on the rotating shaft (10), a No. 4 bevel gear (21) that meshes with the No. 3 bevel gear (20) that is coaxially fixed on one end of the transmission rod (19), a No. 5 bevel gear (22) that is coaxially fixed on the other end of the transmission rod (19), and a No. 6 bevel gear (23) that meshes with the No. 5 bevel gear (22) that is coaxially fixed on the rotating rod (16).

2. The pipe bending strength testing device for underground water conservancy engineering construction according to claim 1, characterized in that, The sleeve (4) is provided with a clamping assembly, which includes a threaded cylinder (7) and a threaded rod (8). The threaded cylinder (7) is fixedly mounted on the sleeve (4) along the diameter direction, and the threaded rod (8) is threadedly engaged with the threaded cylinder (7).

3. The pipe bending strength testing device for underground water conservancy engineering construction according to claim 2, characterized in that, One end of the threaded rod (8) extends into the inside of the sleeve (4), and a clamp (9) is fixedly provided at one end of the threaded rod (8), while a knob is fixedly provided at the other end of the threaded rod (8).

4. The pipe bending strength testing device for underground water conservancy engineering construction according to claim 3, characterized in that, The geared motor (5) is fixedly mounted on the machine base (1), and the output end of the geared motor (5) is coaxially and fixedly connected to one end of one of the rotating shafts (10); A bevel gear (11) is coaxially fixed on one of the rotating shafts (10), and a transmission shaft (12) is rotatably mounted on the swing seat (3).

5. The pipe bending strength testing device for underground water conservancy engineering construction according to claim 4, characterized in that, A second bevel gear (13) is coaxially fixed at one end of the transmission shaft (12), and the second bevel gear (13) meshes with the first bevel gear (11). A first spur gear (14) is coaxially fixed at the other end of the transmission shaft (12), and a second spur gear (15) that meshes with the first spur gear (14) is coaxially fixed on the sleeve (4).

6. The pipe bending strength testing device for underground water conservancy engineering construction according to claim 1, characterized in that, The lifting assembly includes a sliding plate (24) and a cylinder (25). The sliding plate (24) is vertically slidably disposed on the moving plate (6), and the cylinder (25) is vertically fixedly disposed on the moving plate (6). The output end of the cylinder (25) is fixedly connected to the top of the moving plate (6). A bracket (26) is fixedly installed on the movable plate (6), and the roller (2) is rotatably mounted on the bracket (26).

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