Compact on-board belt conveyor tensioning mechanism

Abstract

A compact tensioning mechanism for an onboard belt conveyor includes a hydraulic cylinder (2), two pairs of crossbeams (73) arranged in the same direction as the extension and retraction of the hydraulic cylinder (2), two pairs of slide rails (731) fixed on the inner side of the crossbeams, and rollers (5) that slide and limit along the slide rails (731). The key technical features are: a second column (72) is fixed to the end of each crossbeam (73), and a first column (71) with a through hole (711) is fixed between the crossbeams (73). The slide rails (731) are located between the first column (71) and the second column (72), and are provided with several slots (7311) at equal intervals. The tensioning mechanism can utilize a compact layout space and automatically adjust the tension force according to the inclination angle of the belt conveyor using a tensioning cylinder. This solves the problem of large assembly and disassembly space in traditional structures, achieving automatic tension adjustment and quick disassembly.

Description

Technical Field

[0001] This invention relates to open-pit mining and bulk material loading, unloading and conveying equipment, specifically a compact onboard belt conveyor tensioning mechanism, which is mainly used in bucket wheel excavators or bucket wheel stacker-reclaimers. Background Technology

[0002] In the belt conveyor systems of large bulk material handling equipment such as bucket wheel excavators and bucket wheel stacker-reclaimers, the tensioning mechanism is a core component ensuring the stable operation of the belt. Currently, the mainstream technical solutions can be divided into three categories, but all have significant technical limitations, making it difficult to simultaneously achieve "compact structure," "easy disassembly and assembly," and "reliable tensioning." Specific problems are as follows: Category 1: Hydraulic tensioning-hydraulic locking mechanism: This type of mechanism relies on hydraulic drive to achieve automated control of the tensioning action, dynamically adjusting the tension state according to the belt's operating conditions, offering advantages in tensioning efficiency and response speed. However, its structural design does not consider ease of maintenance, lacking quick-release connections and positioning structures. When the tensioning mechanism needs to be disassembled for equipment maintenance, temporary tooling must be used to complete the disassembly and assembly work. This not only prolongs maintenance time and increases labor costs but also easily affects assembly accuracy due to tooling compatibility issues, leading to reduced efficiency in restoring the belt conveyor to operation and making it difficult to meet the production needs of continuous equipment operation.

[0003] The second type: Helical tensioning-helical locking mechanism: This type of mechanism achieves tensioning and locking by manually turning the helical assembly. While its structural principle is simple, its functionality is limited. On one hand, the tensioning and loosening actions rely entirely on manual operation, making it impossible to automatically adjust the tension and stroke based on real-time operating conditions such as belt slippage or slackness. Manual intervention is only possible after the operator notices an anomaly, resulting in a response lag. On the other hand, the tension control of the helical drive depends on the operator's experience, making precise quantitative adjustment impossible. This can easily lead to excessive tension causing excessive wear on the belt and rollers, shortening their service life, or insufficient tension causing belt slippage and reduced conveying efficiency. Furthermore, unreasonable tension increases equipment energy consumption, failing to meet industry requirements for energy conservation and emission reduction.

[0004] The third type: Hydraulic tensioning-screw locking mechanism: This mechanism adopts a combination of "hydraulic jack-driven tensioning + manual screw component locking". Although the modular design of the screw locking structure improves the ease of assembly and disassembly, solving the disassembly problem of the first two types of mechanisms, its core function still has obvious shortcomings. Its tensioning action relies on manual operation of the hydraulic jack, and the tension force is entirely determined and controlled by human judgment. It cannot achieve precise quantification and automatic adjustment, making it difficult to adapt to the working conditions where the tension force of the conveyor belt changes frequently under different loads and different operating stages. This results in insufficient tension stability and the loss of the core advantage of automated tensioning, failing to balance the technical requirements of "quick disassembly convenience" and "automatic tensioning reliability". Summary of the Invention

[0005] The purpose of this invention is to provide a compact tensioning mechanism for onboard belt conveyors. This tensioning mechanism can utilize a compact layout space and automatically adjust the tension force according to the inclination angle of the belt conveyor using a tensioning cylinder. At the same time, it solves the problem of large assembly and disassembly space in traditional structures, achieving both automatic tension adjustment and quick disassembly.

[0006] To achieve the above objectives, the present invention provides the following technical solution: This compact onboard belt conveyor tensioning mechanism includes a hydraulic cylinder, two pairs of crossbeams arranged in the same direction as the extension and retraction of the hydraulic cylinder, two pairs of slide rails fixed to the inner side of the crossbeams, and rollers that slide and limit along the slide rails. Its key technical features are: A second column is fixed at the end of the crossbeam, and a first column with a through hole in the middle is fixed between the crossbeams. The slide is located between the first column and the second column and is provided with several slots at equal intervals. The ear plate is fixed on the first column. A positioning pin is installed on the ear plate by a wear-resistant copper sleeve. The hydraulic cylinder passes through the through hole and is radially limited by the trunnion set between the outer wall of the hydraulic cylinder and the ear plate. The piston rod of the hydraulic cylinder is hinged to one end of the drum via a first pin, and the other end of the drum is hinged to the positioning plate via a second pin. The positioning plate is adjustablely mounted on the slide rail via a clamping plate.

[0007] Furthermore, the tensioning mechanism is installed on the tracked traveling mechanism, which includes a frame assembly with a base, two sets of symmetrically arranged track assemblies, and each track assembly includes a front drive wheel, a track bracket, a rear support wheel, and several track sections that are connected in series at equal intervals to form a closed loop. The track support is an airfoil structure with a horizontal center and downward ends. The upper center of the track support is equipped with a top support wheel set, and the front and rear ends of the track support are respectively equipped with front support wheels and rear support wheels. The front and rear protrusions of the lower part of the track support are respectively hinged with front travel wheel sets and rear travel wheel sets. The front travel wheel set or rear travel wheel set includes a primary travel frame with a symmetrical structure that is hinged to the track support, a pair of secondary travel frames with a symmetrical structure that are respectively hinged to the front and rear ends of the primary travel frame, a pair of tertiary travel frames with a symmetrical structure that are respectively hinged to the front and rear ends of the secondary travel frames, and four sets of bottom support wheels installed on each tertiary travel frame.

[0008] Furthermore, the inner side of each track section is formed by the outer wall protrusion to form a U-shaped groove. The front support wheel, the rear support wheel, and the bottom support wheel are limited and supported in the U-shaped groove, so that the closed-loop U-shaped groove formed by several track sections is spaced apart from the outer edge of the track support. At the same time, when adjacent track sections rotate in opposite directions around the coaxial axis, the adjacent outer wall protrusions form a meshing groove.

[0009] Furthermore, the front drive wheel is a smooth wheel, and the front drive wheel is fixed with meshing blocks at equal intervals around the center of the circle via meshing block pins. The meshing blocks include meshing protrusions with a pair of pin holes at the bottom and meshing shoulders symmetrically arranged on both sides of the meshing protrusions. The meshing shoulders are inclined downwards, so that the meshing surfaces of the outer edges of each meshing protrusion and the contact surfaces of the outer edges of each meshing shoulder are located on the same annular surface. When the front drive wheel rotates, the meshing protrusions and / or meshing shoulders are engaged in the meshing grooves of the track links.

[0010] The beneficial effects of the present invention are as follows: In terms of the overall technical solution, the present invention achieves multi-dimensional performance optimization through structural innovation, effectively solving the problem of simultaneously realizing automatic adjustment of tension force and rapid assembly and disassembly of hydraulic cylinder within a limited structural space.

[0011] The design employs a rigid "double beam-double column" frame (with a second column fixed to the end of the beam and a first column with a through hole fixed to the middle). The slide rail is welded between the two columns and integrates the roller's axial positioning function. The hydraulic cylinder passes through the through hole in the first column, and the core components have no redundant external structures. This design significantly improves space utilization, adapts to the "high-density layout" requirements of bucket wheel excavators' traveling mechanisms, effectively avoids spatial interference with the traveling drive and transmission systems, and reduces overall space occupancy by more than 30% compared to traditional distributed mechanisms.

[0012] Dynamic belt tension compensation is achieved through a "hydraulic cylinder-piston rod-roller" linkage system: Under operating conditions, the piston rod is driven by hydraulic pressure to move the roller along the slide rail, and the tension stroke is adjusted in real time according to the program settings, without manual intervention; the slide rail groove and positioning plate cooperate to precisely limit the roller displacement, avoiding over-tensioning or under-tension. This function can stabilize the belt tension within the optimal range, significantly reduce the belt slippage rate during heavy-load startup, reduce belt and roller wear, extend component life, and improve conveying efficiency.

[0013] The first column is fitted with a locating pin sleeve using a wear-resistant copper sleeve. The trunnion is hinged to the ear plate via the locating pin sleeve to achieve radial positioning of the hydraulic cylinder. During maintenance, only the clamping plate needs to be fixed to the roller, the hydraulic cylinder oil pressure released, and the locating pin sleeve removed to take out the hydraulic cylinder body and piston rod from the through hole. Compared to the traditional disassembly and assembly process that takes 2-3 hours, this design reduces the disassembly and assembly time of the hydraulic cylinder to less than 30 minutes, significantly reducing equipment downtime losses and lowering labor maintenance costs.

[0014] The drum is axially positioned via a slide rail, with positioning plates symmetrically arranged on both sides of the slide rail. Combined with a locking structure of clamping plates and slots, this effectively prevents drum misalignment caused by vibration. The design of the first column and wear-resistant copper sleeve improves component assembly accuracy and reduces wear and jamming caused by dust and material impact. The overall "frame-limiting" structure can withstand the vibration of the bucket wheel excavator's movement and the harsh environment of the mine, ensuring the long-term operational stability of the mechanism.

[0015] Programmed tension adjustment reduces manual intervention frequency by more than 90%, avoiding frequent entry of operators into confined spaces in the walking mechanism; the quick-release process for hydraulic cylinders is simplified (no bolt tightening or disassembly required), reducing operational complexity and the risks of working at heights or in confined spaces, and improving maintenance safety.

[0016] The tracked walking mechanism adopts a split drive wheel design consisting of a "smooth wheel body + detachable meshing block," with the meshing function achieved by an independent meshing block. When replacing worn meshing blocks, it is not necessary to disassemble the entire drive wheel and shaft system; simply rotate the drive wheel to the non-meshing state and insert or remove the pin to complete the replacement. This saves on spare parts costs, simplifies the operation process, shortens maintenance downtime, reduces labor costs and equipment operation interruption losses, achieving "cost-effective, fast, time-saving, and labor-saving" maintenance.

[0017] In summary, this invention, through its core design of "compactness, automation, and quick disassembly," simultaneously solves the problems of spatial adaptation, stable conveying, and efficient operation and maintenance of the walking mechanism of bucket wheel excavators, providing key technical support for the efficient operation of belt conveyors and possessing significant engineering application value and economic benefits. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the tracked walking mechanism of the present invention in use.

[0019] Figure 1a Figure 1 A magnified schematic diagram of part E in the middle section.

[0020] Figure 2 for Figure 1 A schematic diagram of the front drive wheel.

[0021] Figure 2a for Figure 2 A cross-sectional structural diagram.

[0022] Figure 3 This is a schematic diagram of the main structure of the tensioning mechanism of the present invention.

[0023] Figure 3a This is a top view of the tensioning mechanism of the present invention.

[0024] Figure 4 This is a top view of the tensioning mechanism of the present invention.

[0025] Figure 4a for Figure 4 A partially enlarged structural diagram. Detailed Implementation

[0026] The following combination Figures 1-4 The invention will be described in detail through specific embodiments. Figures 1-2 As shown, the tracked walking mechanism 4 includes a frame assembly with a chassis 432 and two sets of symmetrically arranged track assemblies. Each track assembly includes a front drive wheel 41, a track bracket 43, a rear support wheel 44, and several track sections 42 that are connected in series at equal intervals to form a closed loop.

[0027] The track support 43 is an airfoil structure with a horizontal center and downward ends. The upper center of the track support 43 is provided with a top support wheel set 433. The front and rear ends of the track support 43 are respectively provided with front support wheels 4331 and rear support wheels 4333, and the middle is provided with a middle support wheel 4332. The front and rear protrusions of the lower part of the track support 43 are respectively hinged to the front and rear travel wheel sets 434 and rear travel wheel sets 431. The front travel wheel set 434 or the rear travel wheel set 431 includes a first-level travel frame 4341 with a symmetrical structure that is hinged to the track support 43, a pair of second-level travel frames 4342 with a symmetrical structure that are respectively hinged to the front and rear ends of the first-level travel frame 4341, a pair of third-level travel frames 4343 with a symmetrical structure that are respectively hinged to the front and rear ends of the second-level travel frames 4342, and four sets of bottom support wheels 4344 installed on each third-level travel frame 4343. Each track section 42 has a U-shaped groove formed by an outer wall protrusion 421 on its inner side. The front support wheel 4331, the rear support wheel 4333, and the bottom support wheel 4344 are limited and supported in the U-shaped groove, so that the closed-loop U-shaped groove formed by several track sections 42 is spaced apart from the outer edge of the track bracket 43. At the same time, when adjacent track sections 42 rotate in opposite directions around the coaxial axis, a meshing groove is formed between adjacent outer wall protrusions 421. The front drive wheel 41 is a smooth wheel, which is mounted on the track bracket 43 via the drive shaft 413 and driven by the motor reducer 431. The front drive wheel 41 is fixed with meshing blocks 411 at equal intervals around the center of the circle via meshing block pins 412. The meshing block 411 includes a meshing protrusion 4111 with a pair of pin holes at the bottom and meshing shoulders 4113 symmetrically arranged on both sides of the meshing protrusion 4111. The outer end 4115 of the meshing shoulder 4113 is inclined downward, so that the meshing surface 4112 of the outer edge of each meshing protrusion 4111 and the shoulder contact surface 4114 of the outer edge of each meshing shoulder 4113 are located on the same annular surface. When the front drive wheel 41 rotates, the meshing protrusion 4111 and / or the meshing shoulder 4113 are engaged in the meshing groove of the track link 42.

[0028] The above method allows the meshing block 411 to replace the original drive wheel gear and mesh with the track link. When the meshing block 411 is severely worn and needs to be replaced, the meshing block 411 to be replaced is rotated to a non-meshing state by moving the main unit, the meshing block pin 412 is pulled out, the new meshing block 411 to be replaced is removed, and the new meshing block 411 is replaced. It is then fixed again with the meshing block pin 412 to complete the replacement.

[0029] like Figures 3-4 As shown, a compact onboard belt conveyor tensioning mechanism is mounted on the crawler walking mechanism 4. It mainly consists of a hydraulic cylinder 51, a crossbeam assembly 53, a guide assembly, and a roller adjustment assembly. These components work together to achieve dynamic control of the belt conveyor's tension and enable rapid assembly and disassembly. The crossbeam assembly 53 includes a pair of parallel crossbeams 533, whose extension direction is consistent with the extension and retraction direction of the hydraulic cylinder 51, forming the basic load-bearing frame of the mechanism. Both ends of the crossbeams 533 are rigidly connected to the column assembly: a second column 532 is fixedly connected to each end, while the middle section is connected as a whole by a first column 531. The first column 531 has a through hole 5311 in its middle for the hydraulic cylinder to pass through. This double-column structure enhances the torsional stiffness and support stability of the crossbeam assembly 53.

[0030] The guide assembly consists of a pair of slide rails 5331, which are fixed to the inner wall of the crossbeam 533 by welding and are continuously arranged along the span direction between the first column 531 and the second column 532. The inner wall of the slide rails 5331 has several equally spaced slots 5332 pre-set. The cross-sectional dimensions of the slots 5332 match the positioning components, providing an axial sliding trajectory for the roller 52 and achieving rigid positioning of the roller 52 through a snap-fit ​​structure.

[0031] The assembly structure of the hydraulic cylinder body 51 adopts a modular design: symmetrical ear plates 512 are welded to the outer wall of the first column 531, and locating pin sleeves 5122 are fitted on the outer side of the ear plates 512. A wear-resistant copper sleeve 5121 is embedded between the two, and the self-lubricating properties of the copper sleeve reduce frictional loss during relative rotation. After the hydraulic cylinder body 51 passes through the through hole 5311 of the first column 531, its outer wall forms a radial limiting fit with the ear plates 512 through the trunnion 511. The trunnion 511 and the locating pin sleeve 5122 form a hinge pair, allowing the hydraulic cylinder body 51 to swing slightly around the axis of the trunnion 511, compensating for assembly errors and minor deformations during operation.

[0032] The roller adjustment assembly is the core actuator for achieving the tensioning function. Both ends of the roller 52 are connected to the drive component and the positioning component via pin structures: the side closer to the hydraulic cylinder 51 is hinged to the piston rod 513 of the hydraulic cylinder 51 via a first pin 521, forming the drive end; the side farther from the hydraulic cylinder 51 is hinged to the positioning plate 522 via a second pin 524. The positioning plate 522 is symmetrically arranged on both sides of the slide rail 5331, and its bottom is detachably engaged with the slot 5332 of the slide rail 5331 via a locking plate 523. This structure allows the positioning plate 522 to be adjusted to multiple positions along the slide rail 5331, and the roller 52 is pre-positioned through the cooperation of the locking plate 523 with different slots 5332.

[0033] During operation, when the conveyor belt tension needs to be adjusted, the control system drives the piston rod 513 of the hydraulic cylinder 51 to extend and retract, and drives the roller 52 to slide axially along the slide rail 5331 through the first pin 521. At this time, the positioning plate 522 moves synchronously with the roller, and the clamping plate 523 is in the unlocked state and does not participate in positioning, so as to realize the dynamic stepless adjustment of the tension stroke and ensure that the conveyor belt always maintains the best tension.

[0034] When tension adjustment is required, the piston rod 513 of the hydraulic cylinder 51 pushes the roller 52 to move along the slide rail 5331, and the tension stroke is adjusted at any time according to the program settings. At this time, the positioning plate 522 does not need to be fixed by the clamping plate 523. When the maintenance worker is in operation, the clamping plate 523 is inserted into the clamping groove 5332 of the slide rail 5331 to fix the roller 52. Then, the oil pressure in the hydraulic cylinder 51 is released, the positioning pin sleeve 5122 is pulled out, and the hydraulic cylinder 51 and the piston rod 513 can be removed from the through hole 5311 of the first column 531 at the same time.

[0035] Explanation of reference numerals in the attached drawings: 4 Tracked traveling mechanism, 41 Front drive wheel, 411 Meshing block, 4111 Meshing protrusion, 4112 Meshing surface, 4113 Meshing shoulder, 4114 Shoulder contact surface, 4115 Outer end, 412 Meshing block pin, 413 Drive shaft, 42 Track link, 421 Outer wall protrusion, 43 Track bracket, 431 Rear traveling wheel set, 432 Chassis, 433 Top support wheel set, 4331 Front support wheel, 4332 Middle support wheel, 4333 Rear support wheel, 434 Front traveling wheel set, 4341 Primary traveling frame, 4342 Secondary traveling frame, 4343 Tertiary traveling frame, 4344 Bottom support wheel, 44 Rear support wheel; 5. Tensioning mechanism, 51. Hydraulic cylinder body, 511. Trunnion, 512. Ear plate, 5121. Wear-resistant copper sleeve, 5122. Positioning pin sleeve, 513. Piston rod, 52. Roller, 521. First pin, 522. Positioning plate, 523. Clamping plate, 524. Second pin, 53. Crossbeam assembly, 531. First column, 5311. Through hole, 532. Second column, 533. Crossbeam, 5331. Slide, 5332. Slot.

Claims

1. A compact tensioning mechanism (5) for an onboard belt conveyor, comprising a hydraulic cylinder (51), two pairs of crossbeams (533) arranged in the same direction as the extension and retraction direction of the hydraulic cylinder (51), two pairs of slide rails (5331) fixed inside the crossbeams (533), and rollers (52) that slide and limit along the slide rails (5331), characterized in that: A second column (532) is fixed at the end of the crossbeam (533), and a first column (531) with a through hole (5311) in the middle is fixed between the crossbeams (533). The slide (5331) is located between the first column (531) and the second column (532), and several slots (5332) are provided at equal intervals. The ear plate (512) is fixed on the first column (531). The ear plate (512) is equipped with a positioning pin sleeve (5122) through a wear-resistant copper sleeve (5121). The hydraulic cylinder (51) passes through the through hole (5311) and is radially limited by the trunnion (511) provided between the outer wall of the hydraulic cylinder (51) and the ear plate (512). The piston rod (513) of the hydraulic cylinder (51) is hinged to one end of the roller (52) via the first pin (521), and the other end of the roller (52) is hinged to the positioning plate (522) via the second pin (524). The positioning plate (522) is adjustablely mounted on the slide rail (5331) via the clamping plate (523).

2. The compact onboard belt conveyor tensioning mechanism according to claim 1, characterized in that: The tensioning mechanism is installed on the track walking mechanism. The track walking mechanism (4) includes a frame assembly with a base, two sets of symmetrically arranged track assemblies, and each track assembly includes a front drive wheel (41), a track bracket (43), a rear support wheel (44), and a number of track sections (42) that are connected in series at equal intervals to form a closed loop. The track support (43) is a wing-shaped structure with a horizontal middle section and downward ends. The upper middle section of the track support (43) is provided with a top support wheel set (433). The front and rear ends of the track support (43) are respectively provided with a front support wheel (4331) and a rear support wheel (4333). The front and rear protrusions of the lower part of the track support (43) are respectively hinged to a front travel wheel set (434) and a rear travel wheel set (431). The front travel wheel set (434) or the rear travel wheel set (431) includes a first-level travel frame (4341) with a symmetrical structure that is hinged to the track support (43), a pair of second-level travel frames (4342) with a symmetrical structure that are respectively hinged to the front and rear ends of the first-level travel frame (4341), a pair of third-level travel frames (4343) with a symmetrical structure that are respectively hinged to the front and rear ends of the second-level travel frames (4342), and four sets of bottom support wheels (4344) installed on each third-level travel frame (4343).

3. The long-arm compact bucket excavator according to claim 2, characterized in that: The inner side of each track section (42) is formed by the outer wall protrusion (421) to form a U-shaped groove. The front support wheel (4331), the rear support wheel (4333), and the bottom support wheel (4344) are limited and supported in the U-shaped groove, so that the closed-loop U-shaped groove formed by several track sections (42) is spaced apart from the outer edge of the track support (43). At the same time, when adjacent track sections (42) rotate in opposite directions around the coaxial axis, a meshing groove is formed between adjacent outer wall protrusions (421).

4. The long-arm compact bucket excavator according to claim 2, characterized in that: The front drive wheel (41) is a smooth wheel. The front drive wheel (41) is fixed with a meshing block (411) at equal intervals around the center of the circle by a pin. The meshing block (411) includes a meshing protrusion (4111) with a pair of pin holes at the bottom and meshing shoulders (4113) symmetrically arranged on both sides of the meshing protrusion (4111). The meshing shoulders (4113) are inclined downward so that the meshing surface (4112) of the outer edge of each meshing protrusion (4111) and the shoulder contact surface (4114) of the outer edge of each meshing shoulder (4113) are located on the same annular surface. When the front drive wheel (41) rotates, the meshing protrusion (4111) and / or the meshing shoulder (4113) are engaged in the meshing groove of the track section (42).

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