A belt conveyor idler replacement device

Abstract

The present application belongs to the technical field of roller replacement device, and particularly relates to a belt conveyor roller replacement device, which comprises a jacking assembly and a transfer assembly. The jacking assembly comprises an upper jacking plate and a lower bottom plate, and a pair of X-shaped connecting rods are arranged between the upper jacking plate and the lower bottom plate. Each X-shaped connecting rod is provided with a driving cylinder. A pair of inclined support plates are hingedly connected to the upper jacking plate. A push plate is fixedly connected to the inclined support plate, and a pushing pin matched with the push plate is arranged on the X-shaped connecting rod. The transfer assembly comprises a supporting bottom plate and a transfer sliding block, and the transfer sliding block is slidably connected to the supporting bottom plate. A pull rod is fixedly connected to the transfer sliding block. A second groove is arranged on the transfer sliding block. The device is provided with a clever jacking assembly and an adjustable connecting assembly, and can realize the jacking or lifting of the upper and lower belts, and can be applied to the replacement of various rollers such as middle rollers, inclined rollers and lower rollers, and has high universality.

Description

Technical Field

[0001] This invention belongs to the technical field of idler roller replacement devices, and specifically relates to an idler roller replacement device for a belt conveyor. Background Technology

[0002] Belt conveyors are crucial material handling equipment in industrial production, and their stable operation relies on the effective support of idlers. Idlers, especially the intermediate and inclined idlers in the upper idler mechanism that carry materials, bear heavy loads and wear over long periods, requiring regular replacement. Currently, idler replacement mainly relies on manual operation, which presents numerous difficulties and risks. For inclined idlers located on both sides of the conveyor belt, workers can disassemble them from outside the conveyor, but the operating space is still limited, laborious, and inefficient. For intermediate idlers located directly below the conveyor belt, the replacement process is particularly complex and dangerous: workers must enter the narrow conveyor frame to disassemble and install them within a confined space.

[0003] Due to their significant weight and the substantial resistance to disassembly often caused by accumulated material and corrosion, manual handling and disassembly are extremely difficult. This not only results in high labor intensity and is time-consuming, but also poses a safety hazard of idlers falling and injuring personnel. Furthermore, replacing lower idlers, which support the return belt, also requires manually lifting the belt, making the operation inconvenient. Therefore, current technology lacks a dedicated device that can safely, efficiently, and labor-savingly replace various types of idlers, especially intermediate idlers. This has become a prominent bottleneck restricting the maintenance efficiency and safety of belt conveyors. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention provides a belt conveyor idler replacement device. This replacement device aims to overcome the technical problems of limited operating space, high labor intensity, low efficiency, and high safety hazards that exist in the prior art when manually replacing belt conveyor idlers, especially intermediate idlers.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0006] A belt conveyor idler replacement device includes a lifting assembly and a transfer assembly;

[0007] The lifting assembly includes an upper top plate and a lower bottom plate, and a pair of X-shaped connecting rods are provided between the upper top plate and the lower bottom plate; each X-shaped connecting rod corresponds to a driving cylinder, the cylinder body of the driving cylinder is fixedly connected to the lower bottom plate, and the piston rod of the driving cylinder is fixedly connected to a push plate; when the piston rod of the driving cylinder extends, the push plate pushes the X-shaped connecting rod to move, causing the upper top plate to move upward.

[0008] A pair of diagonal bracing plates are hinged to the upper top plate; a lever plate is fixedly connected to the diagonal bracing plates, and a push pin that cooperates with the lever plate is provided on the X-shaped connecting rod; when the upper top plate moves upward, the push pin pushes the lever plate and the diagonal bracing plates to rotate; a support plate is slidably connected to the upper top plate, an operating rod is fixedly connected to one end of the support plate, and a support plate is fixedly connected to the other end of the support plate, and a first groove is provided on the support plate;

[0009] The transfer assembly includes a supporting base plate and a transfer slider. The transfer slider is slidably connected to the supporting base plate, and a pull rod is fixedly connected to the transfer slider. The transfer slider is provided with a second groove.

[0010] The upper top plate is provided with a limiting component, which includes a bidirectional lead screw and a pair of limiting sliders. The bidirectional lead screw is rotatably connected to the upper top plate, and the limiting sliders are threadedly connected to the bidirectional lead screw and slidably connected to the upper top plate. The pair of limiting sliders are located between a pair of inclined support plates. The pair of limiting sliders can be driven to move relative to or away from each other by rotating the bidirectional lead screw.

[0011] Both ends of the lower base plate are provided with connecting components; the connecting components include support columns and adjusting rods; the adjusting rods are threadedly connected to the support columns, and fixed crossbars are inserted into the adjusting rods, which are provided with corresponding insertion holes.

[0012] The connecting assembly also includes a pushing inclined block and a linkage rod. The support column is slidably connected to the lower base plate, and the support column is provided with a limiting protrusion. The pushing inclined block is slidably connected to the support column, and the support column is provided with a first inclined surface that cooperates with the pushing inclined block. When the pushing inclined block moves, the support column is moved by the cooperation between the pushing inclined block and the second inclined surface.

[0013] The linkage rod is slidably connected to the lower base plate, one end of the linkage rod is fixedly connected to the push block, and the other end of the linkage rod is provided with a baffle; when the piston rod of the drive cylinder retracts, the baffle, linkage rod and push block are moved by the push plate.

[0014] It also includes a support shaft, which is inserted into a fixed crossbar in the connecting assembly.

[0015] The drive cylinder is a multi-stage telescopic cylinder.

[0016] An L-shaped plate is slidably connected to the transfer slider, and a tension spring is provided between the L-shaped plate and the transfer slider.

[0017] The lower end of the L-shaped plate is provided with a second inclined surface; the supporting base plate is provided with a guide post that cooperates with the second inclined surface.

[0018] The supporting base plate is equipped with limiting plates at both ends.

[0019] Compared with the prior art, the beneficial effects of this invention are:

[0020] This device, through the design of the lifting component and the adjustable connecting component, realizes the lifting or pulling of the upper and lower belts, and can be used for various idler replacement scenarios such as intermediate idler, inclined idler, and lower idler.

[0021] Using a drive cylinder (such as a hydraulic cylinder or pneumatic cylinder) as the power source, and amplifying the stroke through a scissor linkage (X-shaped linkage) mechanism, it can easily lift heavy conveyor belts, greatly reducing the labor intensity of workers. At the same time, the lifting action is linked with the unfolding action of the inclined support plate, resulting in a high degree of automation and simple operation.

[0022] The support plate and support tray can be pre-inserted under the intermediate idler before lifting, and smoothly lifted up during the lifting action. Combined with the transfer assembly, this enables the smooth removal of the old idler and the feeding of the new idler.

[0023] An independent mechanical limit assembly (two-way lead screw and limit slider) is set up, which can effectively prevent the top plate from falling back in the event of accidental failure of the drive cylinder, providing crucial secondary safety protection for operators.

[0024] The connecting assembly forms a reliable clamp with the frame via a finely adjustable fixed crossbar, preventing the device from shifting during lifting. The L-shaped plate in the transfer assembly cooperates with the guide column to automatically press or release the idler rollers, ensuring the stability of the idler rollers during transfer and further simplifying the operation. Attached Figure Description

[0025] Figure 1 This is a structural schematic diagram of the lifting component of the present invention in one direction;

[0026] Figure 2 This is a structural schematic diagram of the lifting component of the present invention from another direction;

[0027] Figure 3 This is a schematic diagram of the structure of the transfer component of the present invention;

[0028] Figure 4 This is a schematic diagram of the structure of the lifting component and the transfer component of the present invention placed on the rack;

[0029] Figure 5 This is a schematic diagram of the structure after the upper belt is lifted up;

[0030] Figure 6 It is a cross-sectional view showing the connection between the lifting component and the lower belt;

[0031] Figure 7 yes Figure 6 A magnified view of a section at point B in the middle;

[0032] Figure 8 yes Figure 6A schematic diagram of the structure from another direction shown;

[0033] Figure 9 yes Figure 6 A longitudinal sectional view of the structure shown;

[0034] Figure 10 yes Figure 9 A magnified view of a section at point C;

[0035] Wherein: 1 is the lifting assembly, 10 is the upper top plate, 11 is the lower bottom plate, 12 is the X-shaped connecting rod, 13 is the drive cylinder, 14 is the push plate, 15 is the diagonal brace plate, 16 is the lever plate, 17 is the push pin, 18 is the support plate, 19 is the operating lever, 110 is the support bracket, 111 is the first groove, 112 is the bidirectional lead screw, 113 is the limit slider, 114 is the support column, 115 is the adjusting rod, 116 is the fixed crossbar, 117 is the push inclined block, 118 is the... 119 is the linkage rod, 120 is the first inclined surface, 121 is the baffle, 122 is the support shaft, 2 is the transfer assembly, 20 is the support base plate, 21 is the transfer slider, 22 is the pull rod, 23 is the second groove, 24 is the L-shaped plate, 25 is the tension spring, 26 is the second inclined surface, 27 is the guide post, 28 is the limit plate, 3 is the frame, 4 is the upper belt, 5 is the lower belt, 6 is the upper roller mechanism, 61 is the middle roller, and 7 is the lower roller mechanism. Detailed Implementation

[0036] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0037] like Figures 1 to 3 As shown, a belt conveyor idler replacement device includes a lifting assembly 1 and a transfer assembly 2; the lifting assembly 1 is used to lift the belt, and the transfer assembly 2 is used to transfer the old and new idlers (specifically the intermediate idler 61).

[0038] The lifting assembly 1 includes an upper top plate 10 and a lower bottom plate 11. A pair of X-shaped connecting rods 12 are provided between the upper top plate 10 and the lower bottom plate 11, and the pair of X-shaped connecting rods 12 are arranged opposite to each other. The X-shaped connecting rods 12 are common scissor connecting rods, which are composed of two connecting rods 119 that are hinged in the middle. One end of the two connecting rods 119 is respectively hinged to the upper top plate 10 and the lower bottom plate 11, and the other end of the two connecting rods 119 is respectively slidably connected to the upper top plate 10 and the lower bottom plate 11. The upper top plate 10 and the lower bottom plate 11 are provided with corresponding sliding grooves, and the other end of the two connecting rods 119 is provided with corresponding pins, which are located in the sliding grooves.

[0039] Each X-shaped connecting rod 12 corresponds to a drive cylinder 13. The cylinder body of the drive cylinder 13 is fixedly connected to the lower base plate 11, and the piston rod of the drive cylinder 13 is fixedly connected to a push plate 14. When the piston rod of the drive cylinder 13 extends, it pushes the X-shaped connecting rod 12 to move through the push plate 14, causing the upper top plate 10 to move upward.

[0040] A pair of diagonal bracing plates 15 are hinged to the upper top plate 10; a lever plate 16 is fixedly connected to the diagonal bracing plate 15, and a push pin 17 that cooperates with the lever plate 16 is provided on the X-shaped connecting rod 12; when the upper top plate 10 moves upward, the push pin 17 will drive the lever plate 16 and the diagonal bracing plate 15 to rotate. That is, the movement of the upper top plate 10 and the rotation and unfolding of the diagonal bracing plate 15 can be driven by the drive cylinder 13 alone. Specifically, the push pin 17 is coaxially and integrally fixedly connected to the aforementioned pin shaft.

[0041] like Figure 4 and 5 As shown, the belt conveyor includes a frame 3, an upper idler mechanism 6, and a lower idler mechanism 7. The upper idler mechanism 6 mainly consists of inclined idlers on both sides and a horizontally placed intermediate idler 61. When replacing the inclined idlers, workers can replace them from either side of the belt conveyor. When replacing the intermediate idler 61, workers need to enter the belt conveyor to replace it. The lower idler mechanism 7 mainly consists of a horizontally placed idler.

[0042] The specific steps for replacing the inclined idler are as follows: First, place the lower base plate 11 of the lifting assembly 1 on the frame 3 of the belt conveyor; then, extend the drive cylinder 13 to move the upper top plate 10 upward, and drive the inclined support plate 15 to rotate and unfold. As the piston rod of the drive cylinder 13 gradually extends, the upper belt 4 can be gradually lifted. Finally, the worker can disassemble and replace the inclined idler.

[0043] A support plate 18 is slidably connected to the top plate 10. An operating rod 19 is fixedly connected to one end of the support plate 18, and a support plate 110 is fixedly connected to the other end of the support plate 18. A first groove 111 is provided on the support plate 110, which is used to accommodate the intermediate roller 61.

[0044] When the intermediate idler roller 61 needs to be replaced, after placing the lower base plate 11 of the lifting assembly 1 on the frame 3 of the belt conveyor, first push the support plate 18 to move using the operating lever 19, so that the support plate 110 is located below the intermediate idler roller 61. Then, follow the steps described above (specific steps for replacing the inclined idler roller). Since the support plate 110 is located below the intermediate idler roller 61, the upward movement of the upper top plate 10 will cause the support plate 110 to move upward as well, lifting the intermediate idler roller 61 to be replaced. Therefore, the worker can directly remove the lifted intermediate idler roller 61, achieving the purpose of saving time and effort. At the same time, it can also avoid the problem of difficult replacement for workers due to limited internal operating space and high resistance to disassembly of the intermediate idler roller 61.

[0045] The transfer assembly 2 includes a support base plate 20 and a transfer slider 21. The transfer slider 21 is slidably connected to the support base plate 20, and a pull rod 22 is fixedly connected to the transfer slider 21. The transfer slider 21 is provided with a second groove 23, which is used to accommodate the intermediate roller 61.

[0046] When replacing the intermediate idler roller 61, the support base plate 20 is placed on the frame 3 of the belt conveyor. After the worker removes the lifted intermediate idler roller 61 and places it in the second groove 23 of the transfer slider 21, another worker pulls the lever 22 to move the transfer slider 21 and pull out the disassembled intermediate idler roller 61. After being pulled out, another worker removes the disassembled intermediate idler roller 61 and places the new intermediate idler roller 61 into the second groove 23 of the transfer slider 21; then, another worker pushes the lever 22 to move the transfer slider 21 in the reverse direction and feed it into the belt conveyor; finally, the support plate 18 is pushed to move in the reverse direction and reset, and the worker installs the new intermediate idler roller 61 on the roller frame.

[0047] The above structural design facilitates the transfer of old and new intermediate idler rollers 61.

[0048] Furthermore, such as Figure 1 As shown, to prevent the drive cylinder 13 from failing and causing the upper top plate 10 to lose support and suddenly move downward, a limiting assembly is provided on the upper top plate 10. The limiting assembly includes a bidirectional lead screw 112 and a pair of limiting sliders 113. The bidirectional lead screw 112 is rotatably connected to the upper top plate 10, and the limiting sliders 113 are threadedly connected to the bidirectional lead screw 112 and slidably connected to the upper top plate 10. The pair of limiting sliders 113 are located between a pair of inclined support plates 15. Rotating the bidirectional lead screw 112 drives the pair of limiting sliders 113 to move relative to or away from each other.

[0049] After the upper top plate 10 moves upward and the inclined support plate 15 rotates and unfolds, the double-acting screw 112 drives a pair of limiting sliders 113 to move in opposite directions, so that there is a small gap between the limiting sliders 113 and the corresponding push pins 17. When the drive cylinder 13 fails, the limiting sliders 113 block the push pins 17, preventing the upper top plate 10 from moving downward.

[0050] After the replacement is completed, the bidirectional lead screw 112 is first rotated in the reverse direction to drive a pair of limit sliders 113 to move relative to each other; then the piston rod of the drive cylinder 13 is controlled to retract. Under the action of gravity, the upper top plate 10 moves downward, and the inclined support plate 15 rotates and folds in the reverse direction.

[0051] Furthermore, such as Figure 4As shown, connecting assemblies are provided at both ends of the lower base plate 11; the connecting assemblies include support columns 114 and adjusting rods 115; the adjusting rods 115 are threadedly connected to the support columns 114, and their positions can be finely adjusted by rotating the adjusting rods 115. A fixed crossbar 116 is inserted into the adjusting rods 115, and the adjusting rods 115 are provided with corresponding insertion holes.

[0052] After the lower base plate 11 of the lifting assembly 1 is placed on the frame 3 of the belt conveyor, its height is adjusted by rotating the adjusting rod 115 so that the insertion hole on it is located below the frame 3, and the fixing crossbar 116 is inserted into the insertion hole. The fixing crossbar 116 and the lower base plate 11 cooperate to form a C-shaped clamping structure, which clamps the frame 3 and restricts the movement of the lower base plate 11.

[0053] Furthermore, such as Figures 6 to 10 As shown, the connecting assembly also includes a pushing wedge 117 and a linkage rod 118. The support column 114 is slidably connected to the lower base plate 11. The support column 114 is provided with a limiting protrusion. When the limiting protrusion contacts the lower base plate 11, the support column 114 cannot continue to move down, thus playing a limiting role.

[0054] The linkage rod 118 is slidably connected to the lower base plate 11. One end of the linkage rod 118 is fixedly connected to the push inclined block 117, and the other end of the linkage rod 118 is provided with a baffle 121. The push inclined block 117 is slidably connected to the support column 114. The support column 114 is provided with corresponding through holes and a first inclined surface 120 that cooperates with the push inclined block 117.

[0055] Replacing the idler roller in the lower idler roller mechanism 7 does not require lifting the upper belt 4; therefore, the piston rod of the control drive cylinder 13 retracts, and the push plate 14 pushes the baffle 121, the linkage rod 118, and the pusher block 117 to move. When the pusher block 117 moves, the cooperation between the pusher block 117 and the first inclined surface 120 causes the support column 114 to move upward, and causes the fixed crossbar 116 on it to move upward.

[0056] Specifically, at least two insertion holes are provided on the adjusting rod 115. When it is necessary to replace the idler roller in the lower idler roller mechanism 7, the fixing crossbar 116 is inserted into the lowest insertion hole.

[0057] The replacement process of the idler rollers in the lower idler roller mechanism 7 is as follows: First, place the lower base plate 11 of the lifting assembly 1 on the frame 3 of the belt conveyor; then insert the fixing crossbar 116 into the lowest insertion hole, with the fixing crossbar 116 located below the lower belt 5; finally, by controlling the piston rod of the drive cylinder 13 to retract, the fixing crossbar 116 moves upward to pull up the lower belt 5, so that the lower belt 5 no longer presses against the idler rollers in the lower idler roller mechanism 7, providing sufficient operating space for the replacement of the idler rollers.

[0058] Furthermore, such as Figure 8 As shown, to increase the contact area with the lower belt 5, a support shaft 122 is also included. The support shaft 122 is inserted into the fixed crossbar 116 in the connecting assembly. Before installing the fixed crossbar 116, the support shaft 122 is placed below the lower belt 5, and then the fixed crossbar 116 is installed. In this way, when the piston rod of the drive cylinder 13 retracts, the lower belt 5 is pulled up by the support shaft 122.

[0059] Furthermore, the drive cylinder 13 adopts a multi-stage telescopic cylinder.

[0060] Furthermore, such as Figure 3 As shown, an L-shaped plate 24 is slidably connected to the transfer slider 21, and a tension spring 25 is provided between the L-shaped plate 24 and the transfer slider 21. The L-shaped plate 24 can press the intermediate roller 61 to prevent the intermediate roller 61 from moving arbitrarily during the movement of the transfer slider 21. When it is necessary to remove the intermediate roller 61 from the transfer slider 21, the L-shaped plate 24 can be pulled upward to increase the distance between the L-shaped plate 24 and the transfer slider 21, thereby removing the intermediate roller 61.

[0061] The above operation requires workers to pull the L-shaped plate 24, which is somewhat inconvenient. Therefore, a second inclined surface 26 is provided at the lower end of the L-shaped plate 24; a guide post 27 that cooperates with the second inclined surface 26 is provided on the supporting base plate 20, and the guide post 27 is specifically located in the middle of the supporting base plate 20.

[0062] When the transfer slider 21 moves to the middle of the support base plate 20, the L-shaped plate 24 is lifted by the cooperation of the second inclined surface 26 and the guide post 27, thus eliminating the need for manual operation. When the transfer slider 21 moves outward, the second inclined surface 26 gradually moves away from the guide post 27, and under the action of the tension spring 25, it drives the L-shaped plate 24 to move down and press against the intermediate roller 61.

[0063] Limiting plates 28 are provided at both ends of the support base plate 20 to prevent the support base plate 20 from moving at will, so that the support base plate 20 can be locked onto the frame 3.

[0064] The above description only illustrates preferred embodiments of the present invention, but the present invention is not limited to the above embodiments.

Claims

1. A belt conveyor idler replacement device characterized by: It comprises a jacking assembly (1) and a transfer assembly (2); The jacking assembly (1) comprises an upper top plate (10) and a lower bottom plate (11), and a pair of X-shaped connecting rods (12) are arranged between the upper top plate (10) and the lower bottom plate (11); each X-shaped connecting rod (12) corresponds to a driving cylinder (13), the cylinder body of the driving cylinder (13) is fixedly connected with the lower bottom plate (11), and the piston rod of the driving cylinder (13) is fixedly connected with a pushing plate (14); when the piston rod of the driving cylinder (13) is elongated, the X-shaped connecting rod (12) is pushed to move through the pushing plate (14), so that the upper top plate (10) is moved upward; A pair of inclined support plates (15) are hingedly connected to the upper top plate (10); the inclined support plates (15) are fixedly connected with a pushing plate (16), and the X-shaped connecting rod (12) is provided with a pushing pin (17) matched with the pushing plate (16); when the upper top plate (10) is moved upward, the pushing pin (17) pushes the pushing plate (16) and the inclined support plate (15) to rotate; the upper top plate (10) is slidably connected with a support plate (18), one end of the support plate (18) is fixedly connected with an operating rod (19), and the other end of the support plate (18) is fixedly connected with a support plate (110), and the support plate (110) is provided with a first recess (111); The transfer assembly (2) comprises a support bottom plate (20) and a transfer sliding block (21), the transfer sliding block (21) is slidably connected with the support bottom plate (20), and the transfer sliding block (21) is fixedly connected with a pull rod (22); the transfer sliding block (21) is provided with a second recess (23); Both ends of the lower bottom plate (11) are provided with a connecting assembly; the connecting assembly comprises a support column (114) and an adjusting rod (115); the adjusting rod (115) is threadedly connected with the support column (114), a fixed cross rod (116) is inserted into the adjusting rod (115), and the adjusting rod (115) is provided with a corresponding insertion hole; The connecting assembly further comprises a pushing inclined block (117) and a linkage rod (118), the support column (114) is slidably connected with the lower bottom plate (11), and the support column (114) is provided with a limiting protrusion; the pushing inclined block (117) is slidably connected with the support column (114), and the support column (114) is provided with a first inclined surface (120) matched with the pushing inclined block (117); when the pushing inclined block (117) moves, the support column (114) is driven to move through the cooperation of the pushing inclined block (117) and the second inclined surface (26); The linkage rod (118) is slidably connected with the lower bottom plate (11), one end of the linkage rod (118) is fixedly connected with the pushing inclined block (117), and the other end of the linkage rod (118) is provided with a baffle (121); when the piston rod of the driving cylinder (13) is retracted, the baffle (121), the linkage rod (118) and the pushing inclined block (117) are pushed to move through the pushing plate (14); It further comprises a support shaft (122), and the support shaft (122) is inserted into the fixed cross rod (116) in the connecting assembly.

2. A belt conveyor idler replacement device according to claim 1, characterized in that: The upper top plate (10) is provided with a limiting assembly, the limiting assembly comprises a bidirectional screw rod (112) and a pair of limiting sliding blocks (113), the bidirectional screw rod (112) is rotationally connected with the upper top plate (10), the limiting sliding blocks (113) are threadedly connected with the bidirectional screw rod (112) and are slidingly connected with the upper top plate (10); the pair of limiting sliding blocks (113) are located between the pair of inclined support plates (15); the pair of limiting sliding blocks (113) are driven to move towards or away from each other by rotating the bidirectional screw rod (112).

3. A belt conveyor idler replacement device according to claim 1, characterized in that: The driving cylinder (13) is a multi-stage telescopic cylinder.

4. A belt conveyor idler replacement device according to claim 1, characterized in that: The transfer sliding block (21) is slidingly connected with an L-shaped plate (24), and a tension spring (25) is arranged between the L-shaped plate (24) and the transfer sliding block (21).

5. A belt conveyor idler replacement device according to claim 4, characterized in that: The lower end of the L-shaped plate (24) is provided with a second inclined surface (26), and the support bottom plate (20) is provided with a guide column (27) matched with the second inclined surface (26).

6. A belt conveyor idler replacement device according to claim 1, characterized in that: The support bottom plate (20) is provided with limiting clamping plates (28) at both ends.

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