Multi-size compatible caster automatic assembly device and equipment

Abstract

This invention relates to the field of caster assembly technology, specifically to an automatic assembly device and equipment for multi-size compatible casters, including a guide unit and an insertion unit disposed in the assembly area. The guide unit includes: a guide shaft, horizontally disposed in the assembly area, the diameter of the guide shaft being the same as the diameter of the central shaft; and a first linear actuator, horizontally disposed at the end of the guide shaft, for driving the guide shaft to pass sequentially through the central hole and the mounting hole. The insertion unit includes: a receiving seat, disposed in the assembly area, for receiving the central shaft; and a second linear actuator, disposed on one side of the receiving seat, for driving the receiving seat to move horizontally closer to or away from the guide shaft. This invention ensures the integrity of the central shaft thread and allows for smooth tightening of the subsequent nut, while also preventing wear between the wheel body and the inner wall of the mounting hole, reducing product defect rate and rework losses.

Description

Technical Field

[0001] This invention relates to the field of caster assembly technology, specifically to an automatic assembly device and equipment for multi-size compatible casters. Background Technology

[0002] The manufacturing process of casters is mainly divided into two stages: sub-assembly and final assembly. In the sub-assembly stage, the upper bracket or wheel body of the caster is assembled separately using assembly units, and then the final assembly stage is carried out.

[0003] Chinese Patent Publication No. CN119489331B discloses an automatic caster assembly machine, including a base, a top compartment mounted on the top of the base, a guide seat fixed inside the top compartment, a large number of steel balls inside the top compartment, a vertically upward guide hole in the guide seat, a guide post installed in the guide hole, an electric cylinder connected to the bottom of the guide post installed in the base, the top end of the guide post extending to the top of the guide seat, an assembly seat fixed to the top end of the guide post, the assembly seat being annular, and a [missing information - likely a design feature] on the top surface of the assembly seat. The ball bearing chamber has an upward-facing opening. The mounting base can be lifted by the guide column and uses the ball bearing chamber to assemble the ball bearings onto the casters. A vertical oil chamber is opened inside the guide column, and a piston is installed in the oil chamber. A piston rod is connected to the top of the piston, and the top of the piston rod enters above the mounting base. A pressure seat is installed at the top of the piston rod, and the top surface of the pressure seat protrudes from the top surface of the mounting base. A spring is provided between the top of the pressure seat and the mounting base, and the spring is sleeved on the pressure seat.

[0004] The aforementioned assembly machine is mainly used for assembling the wheel body. However, in the subsequent final assembly stage, existing casters are limited by the usage scenarios, resulting in significant differences in caster size. Different automatic assembly devices are needed to assemble casters of different sizes. Although there are assembly machines that can simultaneously assemble casters of different sizes, when assembling casters of different sizes, multiple factors such as wheel diameter, bracket installation spacing, and component machining tolerances can easily lead to misalignment between the wheel's axle hole and the bracket mounting hole. The equipment needs to dynamically adjust the relative position of the wheel and the bracket in real time to achieve precise alignment of the two holes and ensure smooth installation of the central shaft. However, after long-term continuous operation, the mechanical parts will experience normal wear, decreased accuracy of the positioning mechanism, and increased transmission clearance. At this time, when the equipment performs hole alignment operations according to the preset program, it cannot guarantee complete coaxial alignment between the wheel's axle hole and the bracket mounting hole, which can easily lead to eccentricity and misalignment.

[0005] Forcibly inserting the central shaft in this misaligned state will cause the threaded section at the end of the central shaft to scrape and gnaw against the inner wall of the wheel shaft hole, resulting in wear on the inner wall of the shaft hole and damage to the threaded section at the end of the central shaft used to mate with the nut (if the threaded section is damaged, the central shaft will not be able to mate with the nut, and the central shaft will not be able to stably connect the wheel and the bracket). This will not only cause the caster to rotate slowly, make abnormal noises, and have a significantly shortened service life, but will also directly increase the product defect rate and rework rate, increasing production losses. The chain of deduction for this technical problem is complete, from equipment wear to decreased precision, and then to product defects and increased defect rate. Summary of the Invention

[0006] To address the aforementioned issues, a multi-size compatible automatic caster assembly device and equipment is provided. The core design utilizes a guide shaft that first inserts to correct the coaxiality of the central shaft hole and the mounting hole, and then coordinates with dual linear actuators for synchronous drive to achieve non-destructive insertion of the central shaft. This fundamentally solves the problem of hole misalignment caused by mechanical wear, decreased positioning accuracy, and increased transmission clearance in traditional equipment due to long-term operation. It also avoids hard scraping damage between the central shaft thread and the hole wall, ensuring the integrity of the central shaft thread and smooth tightening of the nut, while eliminating wear between the wheel body and the inner wall of the mounting hole.

[0007] To address the problems of existing technologies, this invention provides an automatic assembly device for multi-size compatible casters. The automatic assembly device has a horizontally arranged guide rail at the top to support the bracket, and an assembly area at the bottom of the guide rail for connecting the bracket and the wheel body. The bracket and the wheel body are hinged together by a central shaft. The wheel body has a central hole for the central shaft to pass through. The bracket includes a rotating frame and a mounting frame, and the rotating frame has a mounting hole for the central shaft to pass through. The automated assembly device includes a guide unit and an insertion unit disposed in the assembly area; The guiding unit includes: A guide shaft is horizontally positioned in the assembly area, and the diameter of the guide shaft is the same as the diameter of the central shaft; A first linear actuator is horizontally disposed at the end of the guide shaft and is used to drive the guide shaft to pass sequentially through the spindle hole and the mounting hole; The insertion unit includes: A receiving seat, disposed in the assembly area, is used to receive the central shaft; A second linear actuator is disposed on one side of the receiving seat and is used to drive the receiving seat to move horizontally closer to or away from the guide shaft.

[0008] Preferably, the end of the guide shaft away from the first linear driver has a first chamfer.

[0009] Preferably, the outer sidewall of the guide shaft and the first chamfer are covered with copper.

[0010] Preferably, a connector is fixedly provided on the output end of the first linear driver, and the connector is detachably assembled with the guide shaft.

[0011] Preferably, a receiving unit is provided below the assembly area, the receiving unit comprising: The receiving wheels are provided in two, and a receiving area for receiving the wheel body is formed between the two receiving wheels; The fifth linear actuator is vertically mounted below the two receiving wheels and is used to drive the two receiving wheels to rise and fall synchronously.

[0012] Preferably, the receiving unit further includes: The lifting seat is vertically movable and positioned below the two receiving wheels and fixedly connected to the output end of the fifth linear actuator; Two connecting rods are provided and are respectively hinged to both sides of the lifting seat, and the receiving wheel is rotatably disposed at the end of the connecting rod away from the lifting seat; A coil spring box is disposed at the hinge point between the connecting rod and the lifting seat and is directly connected to the connecting rod; A pressure sensor is installed on the outer peripheral wall of the receiving wheel.

[0013] Preferably, a pressing unit is disposed above the guide rail, the pressing unit being located directly above the assembly area, and the pressing unit comprising: A pressure roller is positioned above the guide rail, and the pressure roller presses down on the bracket located on the guide rail by its own weight. The pressing frame is vertically positioned above the pressure roller, and the pressure roller is rotatably mounted on the pressing frame.

[0014] Preferably, the receiving seat has a through hole in the vertical direction, and an adjusting block is vertically movable at the through hole, the adjusting block being used to provide support for the central shaft.

[0015] Preferably, the end of the central shaft is provided with a groove, the end of the guide shaft is provided with a protrusion, the protrusion is inserted into the groove, and the end of the protrusion away from the guide shaft is provided with a second chamfer.

[0016] An automatic assembly device for multi-size compatible casters includes a conveying unit, an automatic assembly device for multi-size compatible casters, and a nut installation device.

[0017] The advantages of this invention compared to the prior art are: 1. This invention features a core design that uses a guide shaft to first insert and correct the coaxiality of the center shaft hole and the mounting hole, and then uses a dual linear actuator to synchronously drive the center shaft to achieve non-destructive insertion. This design fundamentally solves the problem of hole misalignment caused by mechanical wear, reduced positioning accuracy, and increased transmission clearance in traditional equipment due to long-term operation. It avoids hard scratch damage between the threaded section of the center shaft and the hole wall, ensuring the integrity of the center shaft thread and smooth tightening of the nut. It also eliminates wear between the wheel body and the inner wall of the mounting hole, solving the defects of subsequent wheel rotation jamming, abnormal noise, and short service life, and reducing product defect rate and rework losses.

[0018] 2. Through the chamfered guide structure, copper cladding layer, and detachable connector of the guide shaft, as well as the pressure monitoring, elastic adaptive structure and central shaft auxiliary fine adjustment structure of the receiving unit, the contact friction damage of the parts can be further weakened, the service life of the core working parts can be extended, and the rapid disassembly and replacement of worn parts can be achieved, reducing equipment downtime and maintenance costs. At the same time, by relying on real-time dynamic correction and precise force adjustment, the accuracy decay caused by the machining tolerance of parts and long-term wear can be offset, ensuring the assembly accuracy of the equipment under long-term continuous operation, maintaining a stable product qualification rate, and taking into account the practicality, durability and ease of maintenance of the equipment. Attached Figure Description

[0019] Figure 1 This is a three-dimensional schematic diagram of an automatic assembly device for multi-size compatible casters according to the present invention. Figure 1 .

[0020] Figure 2 This is a three-dimensional schematic diagram of an automatic assembly device for multi-size compatible casters according to the present invention. Figure 2 .

[0021] Figure 3 This invention relates to an automatic assembly device for multi-size compatible casters. Figure 2 A magnified view of a portion of point A in the middle.

[0022] Figure 4 This is a cross-sectional perspective view of an automatic assembly device for multi-size compatible casters according to the present invention.

[0023] Figure 5 This is a three-dimensional schematic diagram of the automatic assembly device for multi-size compatible casters of the present invention after the limiting slide rail has been removed.

[0024] Figure 6 This is a three-dimensional schematic diagram of the guide unit and insertion unit in the working state of the multi-size compatible caster automatic assembly device of the present invention.

[0025] Figure 7This is a three-dimensional schematic diagram of the automatic assembly device for multi-size compatible casters of the present invention, with the guide unit and insertion unit in working state and the legs removed.

[0026] Figure 8 This is a partial cross-sectional three-dimensional schematic diagram of the guide unit after an explosion in the multi-size compatible automatic assembly device for casters of the present invention.

[0027] Figure 9 This is a three-dimensional schematic diagram of a caster processed by an automatic assembly device for multi-size compatible casters according to the present invention.

[0028] The diagram is labeled as follows: 1. Wheel body; 11. Shaft hole; 2. Bracket; 21. Rotating frame; 211. Mounting hole; 22. Mounting frame; 3. Central shaft; 31. Groove; 4. Guide rail; 41. Limiting slide rail; 411. Correction plate; 412. Fourth linear actuator; 42. Drive unit; 5. Guide unit; 51. Guide shaft; 511. Protrusion; 52. First linear actuator; 53. Connector; 6. Insertion unit; 61. Receiver; 62. Second linear actuator; 63. Adjusting block; 64. Sixth linear actuator; 7. Third linear actuator; 8. Receiver unit; 81. Receiver wheel; 82. Fifth linear actuator; 83. Lifting seat; 84. Connecting rod; 85. Spring box; 9. Pressing unit; 91. Pressure roller; 92. Pressing frame. Detailed Implementation

[0029] To further understand the features, technical means, and specific objectives and functions achieved by the present invention, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

[0030] Reference Figures 1 to 4 , Figure 8 and Figure 9 An automatic assembly device for multi-size compatible casters is provided. The automatic assembly device has a guide rail 4 horizontally arranged above it to support the bracket 2. The lower part of the guide rail 4 is provided with an assembly area for connecting the bracket 2 and the wheel body 1. The bracket 2 and the wheel body 1 are hinged together by a central shaft 3. The wheel body 1 has a central hole 11 for the central shaft 3 to pass through. The bracket 2 includes a rotating frame 21 and a mounting frame 22. The rotating frame 21 has a mounting hole 211 for the central shaft 3 to pass through. The automatic assembly device includes a guide unit 5 and an insertion unit 6 disposed in the assembly area; The guiding unit 5 includes: A guide shaft 51 is horizontally disposed in the assembly area, and the diameter of the guide shaft 51 is the same as the diameter of the central shaft 3; The first linear actuator 52 is horizontally disposed at the end of the guide shaft 51 and is used to drive the guide shaft 51 to pass through the shaft hole 11 and the mounting hole 211 in sequence. The insertion unit 6 includes: A receiving seat 61 is disposed in the assembly area and is used to receive the central shaft 3; The second linear actuator 62 is disposed on one side of the receiving seat 61 and is used to drive the receiving seat 61 to move horizontally closer to or away from the guide shaft 51.

[0031] A third linear actuator 7 is provided at the lower part of both the guide unit 5 and the insertion unit 6. Both third linear actuators 7 are vertically arranged and are used to drive the guide unit 5 and the insertion unit 6 to move up and down, respectively. The guide rail 4 consists of a drive unit 42 and two horizontally parallel limiting slide rails 41. The drive unit 42 can drive the two limiting slide rails 41 to move closer or further apart. Two correction plates 411 are provided on the side where the two limiting slide rails 41 are close together. The correction plates 411 are located below the limiting slide rails 41. A fourth linear actuator 412 is provided on one side of each correction plate 411. The two fourth linear actuators 412 drive the two correction plates 411 to move closer or further apart, respectively. The two correction plates 411 are used to limit the rotation frame 21.

[0032] When the automatic assembly device is in operation, the caster bracket 2 is first horizontally supported and transported by the guide rail 4. After the bracket 2 is smoothly transported to the assembly area, the initial positioning of the bracket 2 is completed. For caster brackets 2 of different sizes, the distance between the two horizontally parallel limit slide rails 41 can be adjusted by the drive unit 42 to adapt to the width of different specifications of mounting brackets 22. At the same time, the fourth linear drive 412 drives the corresponding correction plate 411 to move, accurately limiting the rotating frame 21 in the bracket 2, preventing the rotating frame 21 from shifting during the assembly process, and ensuring the basic positioning accuracy of subsequent assembly operations.

[0033] After the bracket 2 is stably positioned in the assembly area, the wheel body 1 is placed in the assembly area accordingly, so that the axle hole 11 of the wheel body 1 is initially aligned with the mounting hole 211 of the rotating frame 21. Then, the two vertically set third linear actuators 7 are activated to drive the guide unit 5 and the insertion unit 6 to rise and fall respectively. According to the actual size of the caster and the bracket 2, the guide shaft 51 and the receiving seat 61 are adjusted to a suitable height, so that the axis of the guide shaft 51 is close to the coaxiality of the axis of the axle hole 11 and the axis of the mounting hole 211, thus completing the height calibration work before assembly.

[0034] After calibration, the first linear actuator 52 in the guide unit 5 is activated, and the guide shaft 51 is horizontally driven to extend. The guide shaft 51 first passes horizontally through the mounting hole 211 of the rotating frame 21, and then slides into the shaft hole 11 of the wheel body 1. Even if there are problems such as mechanical wear, reduced positioning accuracy, and increased transmission clearance due to long-term use of the equipment, resulting in a coaxiality deviation between the shaft hole 11 and the mounting hole 211, the guide shaft 51 can gradually correct the relative position of the wheel body 1 and the bracket 2 during the horizontal extension process, forcibly achieving complete coaxial alignment between the shaft hole 11 and the mounting hole 211, and completing precise alignment correction.

[0035] After the guide shaft 51 completes the alignment and passes through both the shaft center hole 11 and the mounting hole 211, the end of the guide shaft 51 contacts the end of the central shaft 3, making the axis of the guide shaft 51 collinear with the axis of the central shaft 3. The specific process of the guide shaft 51 aligning with the central shaft 3 is described below. Subsequently, the second linear actuator 62 in the insertion unit 6 is activated. The second linear actuator 62 horizontally drives the receiving seat 61 to move closer to the guide shaft 51, while the first linear actuator 52 drives the guide shaft 51 to retract. The receiving seat 61 and the guide shaft 51 abut against each other and move at the same speed in the same direction. The receiving seat 61 drives the central shaft 3 supported above it to move horizontally synchronously. With the help of the coaxial alignment and positioning completed in advance by the guide shaft 51, the central shaft 3 can smoothly pass through the shaft center hole 11 and the mounting hole 211 along the aligned coaxial path, realizing the non-destructive hinged connection between the central shaft 3, the bracket 2, and the wheel body 1, completing a single caster assembly operation. The above process can be repeated to continuously adapt to the automated assembly of casters of different sizes.

[0036] The core design, achieved through the guide shaft 51 extending into and correcting the coaxiality of the center shaft hole 11 and the mounting hole 211, and then synchronously driven by dual linear actuators to achieve non-destructive insertion of the center shaft 3, fundamentally solves the problem of hole misalignment caused by mechanical wear, decreased positioning accuracy, and increased transmission clearance in traditional equipment due to long-term operation. It avoids hard scraping damage between the threaded section of the center shaft 3 and the hole wall, ensuring the integrity of the center shaft 3 thread and smooth tightening of the nut. It also eliminates wear between the wheel body 1 and the inner wall of the mounting hole 211, resolving the defects of subsequent caster rotation jamming, abnormal noise, and short service life, and reducing costs. The product defect rate and rework loss are reduced. At the same time, relying on the adjustable spacing limit slide rail 41, the independently lifting guide unit 5 and the insertion unit 6, it can flexibly adapt to the assembly needs of casters of different sizes without the need to change special equipment, simplifying the production changeover process, reducing equipment investment and maintenance costs. Moreover, the overall positioning deviation caused by tolerance and equipment wear is offset by real-time dynamic correction. The assembly accuracy can be maintained stably even in long-term continuous production. The coordinated action of each component is smooth and seamless. The overall structure is simple and adaptable to large-scale automated production and easy to maintain and debug later, which comprehensively improves the efficiency, quality and practicality of caster assembly.

[0037] Reference Figures 1 to 9 The end of the guide shaft 51 away from the first linear driver 52 has a first chamfer.

[0038] The first chamfer at the end of the guide shaft 51 serves as a guide transition. During the process of the first linear actuator 52 driving the guide shaft 51 to extend into the mounting hole 211 and the shaft hole 11, the first chamfer contacts the edge of the hole first, weakening the impact force of the hard contact between the guide shaft 51 and the hole wall, and preventing the end of the guide shaft 51 from directly hitting the hole, causing deformation of the hole and scratches on the hole wall. At the same time, with the help of the inclined guide surface of the chamfer, the guide shaft 51 is assisted to slide more smoothly into the misaligned hole, gradually completing the coaxial correction of the wheel body 1 and the bracket 2, further reducing the mechanical damage to the parts during the correction process, ensuring the integrity of the hole structure, and improving the smoothness of the guide shaft 51 extending into the correction, avoiding jamming, and ensuring the continuous and stable assembly process.

[0039] Reference Figures 1 to 9 The outer sidewalls and the first chamfer of the guide shaft 51 are covered with copper.

[0040] The copper cladding layer is relatively soft, which significantly reduces the coefficient of friction between the guide shaft 51 and the mounting hole 211 and the inner wall of the shaft hole 11 compared to the hard metal guide shaft 51 body. Even if there is slight contact friction between the guide shaft 51 and the hole wall, it will not cause hard damage such as scratches or bites to the hole wall. At the same time, it avoids excessive wear of the guide shaft 51 itself due to long-term friction, thus extending the service life of the guide shaft 51. During the process of correcting misaligned holes with the guide shaft 51, the copper cladding layer can buffer contact stress and reduce frictional resistance. It protects the inner wall accuracy of the wheel shaft hole 11 and the mounting hole 211 of the bracket 2, and ensures the correction accuracy of the guide shaft 51 after long-term use. From the material level, it further eliminates assembly damage and completely solves the problem of component wear in the hole position correction process before the insertion of the central shaft 3. Combined with the guiding effect of the first chamfer, it achieves damage-free correction and alignment throughout the entire process.

[0041] Reference Figure 4 and Figure 8 A connector 53 is fixedly provided on the output end of the first linear driver 52, and the connector 53 is detachably assembled with the guide shaft 51.

[0042] The connector 53 enables a detachable connection between the guide shaft 51 and the first linear driver 52. When the guide shaft 51 is worn, it is not necessary to replace the entire guide unit 5 or the first linear driver 52. Only the guide shaft 51 needs to be replaced separately by disassembly and assembly. The operation is simple and quick, which greatly reduces equipment maintenance costs and downtime. At the same time, the guide shaft 51 of the corresponding specification can be quickly replaced according to the assembly requirements of different sized casters, which further improves the device's adaptability to multiple sized casters, ensures that the core calibration components are always in good working condition, maintains the long-term stable assembly accuracy of the device, avoids the decline in assembly quality due to component wear, and takes into account both the convenience of equipment maintenance and the continuity of production.

[0043] Reference Figures 6 to 8 A receiving unit 8 is provided below the assembly area, and the receiving unit 8 includes: There are two receiving wheels 81, and a receiving area for receiving the wheel body 1 is formed between the two receiving wheels 81. The fifth linear actuator 82 is vertically disposed below the two receiving wheels 81 and is used to drive the two receiving wheels 81 to rise and fall synchronously.

[0044] A lifting seat 83 is provided on the output end of the fifth linear actuator 82. A connecting rod 84 is hinged to the lifting seat 83. A coil spring box 85 is provided at the hinge point between the connecting rod 84 and the lifting seat 83. A receiving wheel 81 is rotatably mounted at the end of the connecting rod 84. The coil spring in the coil spring box 85 provides bearing force to the receiving wheel 81. The bearing area formed by the two receiving wheels 81 can stably support the wheel body 1, preventing the wheel body 1 from shaking or shifting during assembly, ensuring that the wheel body shaft hole 11 always remains horizontal and stable, providing a stable foundation for subsequent correction of the guide shaft 51 and insertion of the central shaft 3; wheels of different sizes correspond to different weights, and the downward pressure generated by different weights on the receiving wheel 81 also varies. Unlike other devices, the fifth linear actuator 82 can vertically drive the two receiving wheels 81 to rise and fall synchronously according to preset values ​​and the height and weight of wheel bodies 1 of different sizes. This precisely adjusts the height position of the wheel body 1, allowing the wheel axle hole 11 to quickly align with the mounting hole 211 of the rotating frame 21 at the initial height. In conjunction with the third linear actuator 7, it adjusts the height of the guide unit 5 and the insertion unit 6, further reducing the initial coaxial deviation of the hole position and lowering the difficulty of calibrating the guide shaft 51. At the same time, it adapts to wheel bodies 1 of different diameters and thicknesses, enhancing the multi-size compatibility of the device, ensuring accurate wheel positioning, and preventing calibration failures and assembly misalignment problems caused by wheel height deviations.

[0045] Reference Figure 3 and Figure 8 The receiving unit 8 further includes: The lifting seat 83 is vertically movable and positioned below the two receiving wheels 81 and is fixedly connected to the output end of the fifth linear actuator 82; Two connecting rods 84 are provided and are respectively hinged to both sides of the lifting seat 83. The receiving wheel 81 is rotatably disposed at the end of the connecting rod 84 away from the lifting seat 83. A spring coil box 85 is disposed at the hinge point between the connecting rod 84 and the lifting seat 83 and is directly connected to the connecting rod 84; A pressure sensor is installed on the outer peripheral wall of the receiving wheel 81.

[0046] The fifth linear actuator 82 drives the lifting seat 83 to move vertically, causing the connecting rods 84 on both sides to move synchronously with the receiving wheels 81. The hinged connecting rods 84, in conjunction with the elastic restoring force of the coil spring box 85, can adaptively adjust the distance between the two receiving wheels 81 according to the outer diameter of the wheel body 1. This eliminates the need for manual adjustment, allowing for the adaptation to wheel bodies 1 of different diameters and achieving gapless and stable support, further enhancing the automation level of multi-size adaptation. When the guide shaft 51 inserts into the shaft hole 11 and experiences a height deviation, pressing against the wheel body 1, the wheel body... The pressure applied to the receiving wheel 81 will change. The pressure sensor monitors the force data of the receiving wheel 81 in real time and provides feedback on the force state of the wheel. At this time, the height can be finely adjusted according to the pressure data in conjunction with the lifting seat 83 to counteract the elastic thrust of the coil spring box 85, and avoid the wheel being excessively lifted, which would cause the hole position to be misaligned. This ensures that the wheel position is flexible and adjustable during the calibration process, and can accurately control the force, avoiding assembly deviations caused by excessive elastic force or uneven force. At the same time, it realizes adaptive receiving, simplifies multi-size changeover operations, and improves assembly accuracy and automation level.

[0047] It is worth noting that the coil springs in the coil spring box 85 will experience fatigue after a period of use, and need to be replaced regularly to avoid loss of elasticity.

[0048] Reference Figure 1 and Figure 4 A pressing unit 9 is provided above the guide rail 4. The pressing unit 9 is located directly above the assembly area. The pressing unit 9 includes: A pressure roller 91 is positioned above the guide rail 4, and the pressure roller 91 presses the bracket 2 located on the guide rail 4 by its own weight. The pressing frame 92 is vertically positioned above the pressure roller 91, and the pressure roller 91 is rotatably mounted on the pressing frame 92.

[0049] The pressing unit 9 applies a stable downward pressing force to the bracket 2 in the assembly area using the weight of the pressing roller 91, balancing the upward pushing force of the wheel body 1. This firmly positions the bracket 2 on the guide rail 4, preventing the bracket 2 from being lifted and displaced. This ensures that the position of the rotating frame 21 and the mounting hole 211 on the bracket 2 remains fixed, avoiding the failure of the initial positioning and correction due to the displacement of the bracket 2. The pressing frame 92 guides and limits the pressing roller 91 in the vertical direction, ensuring that the pressing roller 91 can only move up and down in the vertical direction and will not be horizontally offset as the bracket 2 is conveyed or pushed by the wheel. This ensures that the pressing position is always accurately aligned with the bracket 2 in the assembly area. At the same time, the pressing roller 91 is set to rotate, so it will not obstruct the normal conveying of the bracket 2 on the guide rail 4. It only plays a pressing and limiting role during assembly positioning, taking into account both the smoothness of the bracket 2's conveying and the stability of the assembly positioning. Together with the wheel support of the receiving unit 8, it achieves bidirectional positioning of the bracket 2 and the wheel, further consolidating the hole position correction accuracy and preventing the displacement of parts during the assembly process.

[0050] Reference Figures 5 to 7 The receiving seat 61 has a through hole along the vertical direction, and an adjustment block 63 is vertically movable at the through hole. The adjustment block 63 is used to provide support for the central shaft 3.

[0051] A sixth linear actuator 64 is provided at the lower part of the adjusting block 63. The sixth linear actuator 64 is used to drive the adjusting block 63 to move in the vertical direction.

[0052] As the basic support component of the central shaft 3, the support seat 61 needs to be replaced when producing casters of different sizes. That is, the support seat 61 and the output end of the second linear drive 62 can be detached and fitted together so that the support seat 61 can be adapted to the size of the central shaft 3. However, relying solely on its own support is insufficient to accommodate center shafts 3 of different diameters and lengths, nor can it achieve fine-tuning of the axis of the center shaft 3. The adjustment block 63 set inside the through hole, in conjunction with the sixth linear actuator 64, enables secondary fine-tuning of the height of the center shaft 3. After the third linear actuator 7 completes the overall coarse adjustment of the height of the support 61, the sixth linear actuator 64 can drive the adjustment block 63 to move vertically within a small range along the through hole, precisely adjusting the local height of the center shaft 3. The adjustment block 63 provides multi-point auxiliary support for the center shaft 3, preventing the slender center shaft 3 from drooping or shifting, ensuring that the center shaft 3 always remains horizontal and stable. Together with the support 61, it completes double support and precise positioning, further improving the coaxiality of the center shaft 3 insertion, enhancing the non-destructive assembly effect, adapting to the support and positioning requirements of center shafts 3 of different specifications, and improving the adaptability and assembly accuracy of the device.

[0053] Reference Figure 8The end of the central shaft 3 is provided with a groove 31, and the end of the guide shaft 51 is provided with a protrusion 511. The protrusion 511 is inserted into the groove 31, and the end of the protrusion 511 away from the guide shaft 51 is provided with a second chamfer.

[0054] After the guide shaft 51 completes the coaxial alignment of the hole position, the protrusion 511 at the end, guided by the second chamfer, smoothly inserts into the groove 31 at the end of the central shaft 3. Even if there is a slight axial deviation between the central shaft 3 and the guide shaft 51, the second chamfer can buffer the impact force of the connection and assist the protrusion 511 in smoothly locking into the groove 31, completing the insertion and positioning of the two. After the protrusion 511 and the groove 31 cooperate, the guide shaft 51 and the central shaft 3 are forced to form a coaxial and collinear state, directly transmitting the accurate coaxiality of the guide shaft 51 after alignment to the central shaft 3, eliminating the insertion misalignment problem caused by the offset of the central shaft 3 itself, and ensuring that the central shaft 3 is inserted into the hole position completely along the aligned coaxial path. This further eliminates the scratch damage between the thread section and the hole wall during the connection process. At the same time, this insertion and connection structure is simple, and the connection and separation are smooth. It will not affect the synchronous action of the guide shaft 51 retraction and the central shaft 3 advancement. This not only enhances the coaxial positioning accuracy but also ensures the continuity of the assembly action, further consolidating the core technical effect of independent non-destructive assembly and precise alignment, and solving various assembly defects caused by eccentric misalignment.

[0055] Reference Figures 1 to 9 An automatic assembly device for multi-size compatible casters includes a conveying unit, an automatic assembly device for multi-size compatible casters, and a nut installation device.

[0056] Working principle: The conveying unit is set on the guide rail 4. The conveying unit can use a push plate or wheel conveying method for conveying. The multi-size compatible caster automatic assembly device and the nut installation device are arranged along the extension direction of the guide rail 4. The bracket 2 that moves on the guide rail 4 first passes through the multi-size compatible caster automatic assembly device and then passes through the nut installation device.

[0057] During assembly, the brackets 2 are first placed sequentially on the guide rails 4, and the conveying unit drives the brackets 2 on the guide rails 4 to move. A position sensor is set above the guide rails 4 to locate the position of the moving brackets 2. The position sensor is existing technology and is not shown in the attached drawings of the specification. In actual production, different position sensors can be selected as needed. The function of the position sensor is to determine whether the brackets 2 have moved to the assembly position. After confirming that the brackets 2 have moved to the designated assembly position, the conveying unit stops conveying. Then, the wheel body 1 is fitted with the brackets 2 so that the shaft hole 11 on the wheel body 1 can be aligned with the mounting hole 211 on the rotating frame 21. Finally, under the guidance of the guiding unit 5, the central shaft 3 is inserted without damage and passes through the shaft hole 11 and the mounting hole 211 to avoid wear of the thread at the end of the central shaft 3 with the shaft hole 11 and the mounting hole 211 during the insertion process. After the central shaft 3 is inserted, the conveying unit starts again. The conveying unit drives the bracket 2 with the central shaft 3 inserted and the wheel body 1 to move towards the nut mounting device. The nut mounting device screws the nut into the threaded section at the end of the central shaft 3, thus completing the assembly.

[0058] Due to the differences in caster dimensions, the dimensions of bracket 2 also differ. Therefore, the spacing between the two limiting slide rails 41 needs to be adjusted according to the dimensions of bracket 2. During adjustment, the two limiting slide rails 41 are driven to move closer or further apart by the drive unit 42. The drive unit 42 is a lead screw type. By adjusting the spacing between the two limiting slide rails 41, the two limiting slide rails 41 can effectively support and limit the mounting bracket 22 in bracket 2, preventing the mounting bracket 22 from wobbling on the guide rail 4 when it moves along the extension direction of the guide rail 4. At the same time, the two correction plates 411 limit the rotating frame 21 under the drive of the two fourth linear actuators 412, preventing the rotating frame 21 from shifting during the movement of the mounting bracket 22, which would prevent the wheel body 1 from being properly installed on the rotating frame 21.

[0059] After completing the above adjustments, the specific connection process between the wheel body 1 and the bracket 2 is as follows: After the conveying unit transports the bracket 2 to the assembly area, the position sensor positions the bracket 2. Subsequently, the conveying unit stops operating, and the rotating frame 21 in the bracket 2 stops in the assembly area. The robot or the dedicated conveying channel for the wheel body 1 transports the wheel body 1 to the receiving area formed by the two receiving wheels 81. The two receiving wheels 81 receive the wheel body 1, and the axis of the wheel body 1 is parallel to the axis of the receiving wheels 81. At the same time, the robot or the dedicated conveying channel for the central shaft 3 transports the central shaft 3 to the receiving seat 61. At this time, the output end of the sixth linear actuator 64 is in an extended state, and the adjusting block 63 supports the central shaft 3. With the joint support of the adjusting block 63 and the receiving seat 61, the central shaft 3 is in a horizontal state. Subsequently, the third linear actuator 7 drives the receiving seat 61 to rise to a specified height, making the axis of the central shaft 3 collinear with the axis of the mounting hole 211 on the rotating frame 21. At the same time, the fifth linear actuator 82 drives the lifting seat 83 to rise to a specified height, making the mounting hole 211 on the rotating frame 21 aligned with the axle hole 11 on the wheel body 1. However, after long-term use, after the receiving seat 61 reaches the specified height, the axis of the central shaft 3 may deviate from the axis of the mounting hole 211. Similarly, when the lifting seat 83 rises to the specified height, there will also be a deviation between the axle hole 11 on the wheel body 1 and the mounting hole 211 on the rotating frame 21. To prevent the threaded end of the central shaft 3 from being worn when inserted into the bracket 2 and the wheel body 1, a guide unit 5 is provided to guide the central shaft 3. When both the receiving seat 61 and the lifting seat 83 reach the specified height, the first linear actuator 52 drives the guide shaft 51 to extend. The rotating frame 21 has two coaxially arranged mounting holes 211. The extended guide shaft 51 first passes through one of the mounting holes 211 and slides into the shaft hole 11 of the wheel body 1. Since the end of the guide shaft 51 is provided with a first chamfer, and the outer sidewall of the guide shaft 51 and the first chamfer are covered with copper, even if there is a deviation between the mounting hole 211 and the shaft hole 11, the inserted guide shaft 51 is not likely to cause wear on the inner wall of the shaft hole 11. When the guide shaft 51 passes through the mounting hole 211 and the shaft hole 11 at the same time, the guide shaft 51 completes the correction work of the bracket 2 and the wheel body 1, so that the shaft hole 11 and the mounting hole 211 are completely aligned.

[0060] It is worth noting that the receiving unit 8 can support wheel bodies 1 of different sizes. Specifically, under the restoring force of the coil spring in the coil spring box 85, the connecting rod 84 can provide effective support for the receiving wheel 81, enabling the two receiving wheels 81 to effectively support wheel bodies 1 of different sizes. Simultaneously, since the receiving wheel 81 is equipped with a pressure sensor, when the guide shaft 51 is simultaneously inserted into the mounting hole 211 and the axle hole 11, if the axle hole 11 is higher than the mounting hole 211, the guide shaft 51 will press down on the wheel body 1 when inserted into the axle hole 11, causing the receiving wheel 81 to be subjected to pressure. As the force increases, the coil spring in the coil spring box 85 coils up further, and the pressure detected by the pressure sensor rises. However, since the guide shaft 51 has already been inserted into the shaft hole 11, in order to avoid the reset spring force of the coil spring box 85 generating excessive upward thrust on the wheel body 1, the fifth linear actuator 82 drives the lifting seat 83 to descend. At this time, the pressure sensor monitors the pressure change in real time. When the pressure decreases to the preset value (the pressure generated on the receiving wheel 81 when the wheel body 1 is placed on the receiving wheel 81 without external force is the preset value), the fifth linear actuator 82 stops running.

[0061] When the central shaft 3 completely passes through the shaft hole 11 and emerges from another mounting hole 211 on the rotating bracket 21, the protrusion 511 at the end of the guide shaft 51 inserts into the groove 31 of the central shaft 3. Since the end of the protrusion 511 away from the guide shaft 51 has a second chamfer, even if there is a deviation between the axis of the mounting hole 211 and the axis of the central shaft 3, the protrusion 511 can still smoothly insert into the groove 31. After the protrusion 511 is inserted into the groove 31, the axis of the guide shaft 51 becomes collinear with the axis of the central shaft 3, thereby achieving the correction of the position of the guide shaft 51 on the central shaft 3. Subsequently, the first linear actuator 52 drives the guide shaft 51 to retract, and the second linear actuator 62 retracts along the guide shaft 51. The guide shaft 51 moves closer to the support 2 at the same speed as the bearing 61. At this time, the end of the guide shaft 51 abuts against the end of the central shaft 3. Since the guide shaft 51 has already corrected the shaft hole 11 and the mounting hole 211, and during the retraction of the guide shaft 51, the central shaft 3 is inserted into the mounting hole 211 and the shaft hole 11 at the same speed as the guide shaft 51 in the retracted state. Therefore, the threaded section at the end of the central shaft 3 will not scrape against the inner wall of the shaft hole 11. This avoids wear on the threaded section of the central shaft 3 and damage to the inner wall of the shaft hole 11 during insertion. This ensures that the nut can be smoothly installed onto the threaded section of the central shaft 3 and that the wheel body 1 rotates stably during subsequent use.

[0062] It is worth noting that when the receiving unit 8 lifts the wheel body 1 to the specified height, the wheel body 1 will lift the bracket 2 due to factors such as tolerance when it is engaged with the bracket 2. In order to prevent the bracket 2 from being lifted by the wheel body 1, a pressure roller 91 is set directly above the assembly area. The pressure roller 91 presses the bracket 2 in the assembly area by its own weight to prevent the bracket 2 from being lifted. The pressing frame 92 set on the upper part of the pressure roller 91 can guide the pressure roller 91 to move in the vertical direction, so that the pressure roller 91 can only move in the vertical direction. In addition, a connector 53 is provided on the output end of the first linear driver 52. The connector 53 is disassembled and assembled with the guide shaft 51, so that the guide shaft 51 can be replaced. This is because after long-term use, the guide shaft 51 will wear out due to frequent correction of the relative position of the bracket 2 and the wheel body 1. If the guide shaft 51 is not replaced in time, the guide shaft 51 will be unable to effectively correct the bracket 2 and the wheel body 1. In this invention, the connector 53 and the guide shaft 51 are threaded together, which facilitates the replacement of the guide shaft 51 in subsequent maintenance.

[0063] The above embodiments only illustrate one or more implementations of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of protection of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the appended claims.

Claims

1. An automatic assembly device for multi-size compatible casters, wherein a guide rail (4) is horizontally arranged above the automatic assembly device to support a bracket (2), and an assembly area is provided at the lower part of the guide rail (4) for connecting the bracket (2) and the wheel body (1). The bracket (2) and the wheel body (1) are hinged together by a central shaft (3). The wheel body (1) is provided with a central hole (11) through which the central shaft (3) passes. The bracket (2) includes a rotating frame (21) and a mounting frame (22). The rotating frame (21) is provided with a mounting hole (211) through which the central shaft (3) passes. Its features are, The automatic assembly device includes a guide unit (5) and an insertion unit (6) disposed in the assembly area; The guiding unit (5) includes: A guide shaft (51) is horizontally disposed in the assembly area, and the diameter of the guide shaft (51) is the same as the diameter of the central shaft (3). The first linear actuator (52) is horizontally disposed at the end of the guide shaft (51) and is used to drive the guide shaft (51) to pass through the shaft hole (11) and the mounting hole (211) in sequence. The insertion unit (6) includes: A receiving seat (61) is provided in the assembly area for receiving the central shaft (3). A second linear actuator (62) is disposed on one side of the receiving seat (61) for driving the receiving seat (61) to move horizontally toward or away from the guide shaft (51).

2. The automatic assembly device for multi-size compatible casters according to claim 1, characterized in that, The end of the guide shaft (51) away from the first linear driver (52) has a first chamfer.

3. The automatic assembly device for multi-size compatible casters according to claim 2, characterized in that, The outer sidewalls of the guide shaft (51) and the first chamfer are covered with copper.

4. A multi-size compatible automatic caster assembly device according to any one of claims 1 to 3, characterized in that, A connector (53) is fixedly provided on the output end of the first linear driver (52), and the connector (53) is detached and assembled with the guide shaft (51).

5. The automatic assembly device for multi-size compatible casters according to claim 1, characterized in that, A receiving unit (8) is provided below the assembly area, and the receiving unit (8) includes: There are two receiving wheels (81), and a receiving area for receiving the wheel body (1) is formed between the two receiving wheels (81); The fifth linear actuator (82) is vertically disposed below the two receiving wheels (81) and is used to drive the two receiving wheels (81) to rise and fall synchronously.

6. The automatic assembly device for multi-size compatible casters according to claim 5, characterized in that, The receiving unit (8) further includes: The lifting seat (83) is vertically movable and positioned below the two receiving wheels (81) and fixedly connected to the output end of the fifth linear actuator (82); Two connecting rods (84) are provided and are respectively hinged to both sides of the lifting seat (83). The receiving wheel (81) is rotatably disposed at the end of the connecting rod (84) away from the lifting seat (83). A coil spring box (85) is provided at the hinge point between the connecting rod (84) and the lifting seat (83) and is directly connected to the connecting rod (84); A pressure sensor is disposed on the outer peripheral wall of the receiving wheel (81).

7. The automatic assembly device for multi-size compatible casters according to claim 5 or 6, characterized in that, A pressing unit (9) is provided above the guide rail (4). The pressing unit (9) is located directly above the assembly area. The pressing unit (9) includes: A pressure roller (91) is positioned above the guide rail (4), and the pressure roller (91) presses the bracket (2) on the guide rail (4) by its own weight. The pressing frame (92) is arranged vertically above the pressure roller (91), and the pressure roller (91) is rotatably mounted on the pressing frame (92).

8. The automatic assembly device for multi-size compatible casters according to claim 1, characterized in that, The receiving seat (61) has a through hole in the vertical direction, and an adjustment block (63) is vertically movable at the through hole. The adjustment block (63) is used to provide support for the central shaft (3).

9. The automatic assembly device for multi-size compatible casters according to claim 1, characterized in that, The central shaft (3) has a groove (31) at its end, and the guide shaft (51) has a protrusion (511) at its end. The protrusion (511) is inserted into the groove (31), and the end of the protrusion (511) away from the guide shaft (51) has a second chamfer.

10. An automatic assembly equipment for multi-size compatible casters, characterized in that, It includes a conveying unit, a multi-size compatible automatic caster assembly device as described in any one of claims 1-9, and a nut installation device.

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