Steel bar truss automatic production line and process flow thereof

Abstract

This invention discloses an automated production line for steel trusses and its process flow, relating to the field of intelligent welding technology for steel trusses. It includes: a main reinforcement pretreatment unit, comprising a vibratory paving machine, a first conveyor for equidistantly conveying the main reinforcement bars, and end processing devices for thickening and tapping the ends of the main reinforcement bars. The first conveyor and vibratory paving machine are arranged side-by-side, and the end processing devices are located at opposite ends of the first conveyor. A main reinforcement material storage unit includes a roller conveyor assembly for receiving and horizontally transferring the main reinforcement bars, a vertical lift for vertically lifting the main reinforcement bars, and a rack for storing the main reinforcement bars according to specifications. The vertical lift and rack are arranged side-by-side, and the roller conveyor assembly is located at the outlet of the first conveyor. Through automated material flow, the problem of inconsistent quality in existing on-site construction processes is effectively solved, ensuring the consistency and reliability of the steel truss products.

Description

Technical Field

[0001] This invention relates to the field of intelligent welding technology for steel trusses, and more specifically, to an automated production line for steel trusses and its process flow. Background Technology

[0002] Steel truss technology is mainly used in the field of prefabricated buildings. With the development of technology in recent years, the production process has gradually moved towards automation, and a variety of automated equipment for steel bar conveying, feeding and bending has emerged. Their emergence has improved production efficiency and reduced labor costs. However, there is still a lack of fully automatic truss machines on the market that can further improve production efficiency.

[0003] Currently, most existing methods for treating beams and columns rely on manual labor to arrange bent stirrups according to the required building specifications before welding. This process consumes a significant amount of labor. Due to the lack of standardized production processes, the quality of these on-site construction methods for bending stirrups and then assembling and welding them with the main reinforcement is inconsistent. Some require manual assistance, while others, although equipped with mechanical bending equipment and equipment for assembling and welding stirrups and main reinforcement, lack a systematic material transport connection between these devices. Material flow between workstations depends on manual or semi-automatic methods. Bending, arranging, assembling, and welding processes are handled separately without a unified transport line, resulting in poor material transfer between processes and low production efficiency.

[0004] To address the aforementioned issues, an automated production line for steel trusses and its technological process are proposed. Summary of the Invention

[0005] To solve the above-mentioned technical problems, an automated production line for steel trusses and its process flow are provided. This technical solution solves the problems mentioned in the background technology.

[0006] To achieve the above objectives, the present invention can be implemented using the following technical solutions: This invention provides an automated production line for steel trusses, comprising: The main reinforcement pretreatment unit includes a vibratory paving machine, a first conveyor for equidistantly conveying the main reinforcement, and an end processing device for upsetting and tapping the two ends of the main reinforcement, wherein the first conveyor and the vibratory paving machine are arranged side by side, and the end processing devices are located at both ends of the first conveyor. The main reinforcement material storage unit includes a set of roller conveyors for receiving the main reinforcement and transferring it horizontally, a vertical elevator for vertically lifting the main reinforcement, and a rack for storing the main reinforcement according to specifications. The vertical elevator and the rack are arranged side by side, and the set of roller conveyors is located at the outlet of the first conveyor and aligned with the vertical elevator. The main rib pre-positioning unit includes a first conveying bracket capable of adjusting the spacing of the main ribs, and a third material handling robot for transferring the main ribs one by one from the material rack to the first conveying bracket. The first conveying bracket is located on the side of the material rack away from the vertical elevator. The hoop forming unit is used to bend and weld steel bars into hoops; The hoop feeding unit includes a second conveyor for conveying hoops, an arranging frame for neatly arranging hoops, and a pushing mechanism for pushing the hoops one by one from the second conveyor into the arranging frame. The arranging frame is arranged side by side on one side of the second conveyor, and the pushing mechanism is arranged on the side of the arranging frame away from the second conveyor. A fifth linear guide rail is provided at the bottom of the arranging frame, which can move the arranging frame as a whole to be aligned with one end of the first conveying support. A welding motion support includes a multi-moving sub-slide, a third linear guide fixedly installed on the top of each slide, and a second conveying support fixedly installed on the top of the slider of the third linear guide. Both the first and second conveying supports include multiple main rib supports. The multi-moving sub-slide is arranged parallel to the arranging frame and is located on the side away from the second conveyor. When the arranging frame is translated and aligned with the first conveying support, the slider of the third linear guide can drive the second conveying support to translate, so that the multiple main rib supports it includes are inserted into the gaps between multiple hoops in the arranging frame. The four-sided welding unit is located at the end of the arrangement frame away from the first conveying support and on one side of the multi-moving sub-slide table, and is used to weld the steel truss after the main reinforcement and the hoop are combined.

[0007] Furthermore, the main reinforcement pretreatment unit also includes a first material handling robot, used to transfer the orderly arranged main reinforcement bars from the vibratory paving machine to the first conveyor one by one. The end processing device includes two upsetting machines and two tapping machines. The bottom of the upsetting machines and tapping machines are equipped with a first linear guide rail, used to push the working ends of the upsetting machines and tapping machines toward the ends of the main reinforcement bars.

[0008] Furthermore, there are two sets of roller conveyor sets, which are respectively located at both ends of the discharge port of the first conveyor. A second linear guide rail is provided at the bottom of the roller conveyor set to push the roller conveyor set so that its rollers contact the two ends of the main rib, so that the main rib enters the gap between the rollers of the roller conveyor set. The main reinforcement material storage unit also includes a second material handling robot that transfers the main reinforcement from the vertical elevator to the material rack.

[0009] Furthermore, the main support includes an upright lead screw guide rail, a nut slider that fits inside the lead screw guide rail, the nut slider including multiple first slide plates that slide inside the lead screw guide rail, a nut that is rotatably connected inside the first slide plates, the nut being threaded onto the lead screw inside the lead screw guide rail, and multiple screw guide rails that are set at the height of each first slide plate, the screw guide rails being arranged horizontally, a screw slider that fits inside the screw guide rail, the screw slider including a second slide plate that slides inside the screw guide rail, a screw that is rotatably connected to one end of the second slide plate, the screw being threaded onto one end of the screw guide rail, the second slide plate being fixedly connected to the first slide plate; The main support also includes a sliding shaft rotatably connected to the end of the second slide away from the screw. The sliding shaft passes through the end of the screw guide away from the screw and extends outward. Multiple rollers are sleeved on the outside of the extended section of the sliding shaft. The outermost roller is fixedly connected to the sliding shaft, and the remaining rollers slide with the outside of the sliding shaft. Springs are sleeved on the outside of the sliding shaft between adjacent rollers. The main support frame also includes motor one, motor two and motor three, which are fixedly installed on each of the second slide plates. Motor one is used to drive the nut to rotate, motor two is used to drive the screw to rotate, and motor three is used to drive the sliding shaft to rotate. The first conveying support includes multiple main rib supports arranged at equal intervals in parallel. In the second conveying support, the bottom of each lead screw guide rail is fixedly installed on the top of the slider of each third linear guide rail.

[0010] Furthermore, the hoop forming unit includes a rebar straightening machine, a CNC bending machine located at one end of the rebar straightening machine, the CNC bending machine being used to bend the rebar to form hoop bars and stirrups, and a resistance welding device located at one end of the CNC bending machine being used to weld the hoop bars and stirrups together to form a hoop.

[0011] Furthermore, the hoop loading unit includes a fourth material handling robot that transfers the hoop from the resistance welding equipment to the second conveyor. The second conveyor is a chain conveyor, with multiple slot clamps evenly and fixedly connected around the chain. When the slot clamp moves above the second conveyor, its slot opening points directly upward, so that the hoop inside the slot clamp is in an upright conveying state. The pushing mechanism includes a fourth linear guide rail parallel to the second conveyor, and a third conveyor fixedly installed on the top of the slider of the fourth linear guide rail. The third conveyor is a single-chain conveyor. The slider of the fourth linear guide rail moves in a direction perpendicular to the chain rotation surface of the third conveyor. A push hook is fixedly connected to the side of the chain of the third conveyor. When the chain of the third conveyor drives the push hook to move towards the second conveyor, it can push the hoops in the slot into the arrangement frame. The slider movement direction of the fifth linear guide is perpendicular to the movement direction of the mover of the multi-mover slide table. There are crossbeams at the top and bottom inside the arrangement frame. Multiple slots are evenly fixedly connected on the opposite sides of the crossbeams along their length. The spacing between the upper and lower slots is consistent with the height of the hoop when it is upright, and the slot openings are opposite each other. When the slot clamp moves to align with a certain slot, the hoop inside it can be pushed into the slot by the pushing mechanism.

[0012] Furthermore, the four-sided welding unit includes an upright rectangular frame, which is located at the end of the arrangement frame away from the first conveying support and on one side of the multi-moving sub-slide table. The frame opening of the rectangular frame is aligned with the first conveying support. Sixth linear guides are fixedly installed on all four sides of the rectangular frame along its length. Welding robots are fixedly installed on the sliders of the sixth linear guides. Visual recognition sensors are also provided on the rectangular frame to identify the spatial position of the welding nodes.

[0013] According to the process flow of an automated production line for steel trusses according to any of the above, the process includes the following steps: S1. After the vibratory paving machine aligns the main reinforcement bars, it transfers them to the first conveyor for horizontal equidistant feeding. During feeding, it adopts an intermittent stopping method, and when stopping, it performs pre-treatment by thickening and tapping the two ends of the main reinforcement bars. Then, the treated main reinforcement bars are sorted by specifications and stored in the material rack by the vertical elevator. S2. Based on the required steel truss dimensions, pre-set parameters to control the rollers in the main reinforcement prefabrication unit, so that the horizontal and vertical spacing between them can be adjusted to achieve the set spacing. The third material handling robot will transfer the main reinforcement of beams and columns of different specifications from the material rack to the first conveying support one by one. S3. The hoop feeding unit arranges the bent hoop bars according to the required spacing, and then transfers the arranged hoop bars to the arranging frame. The arranging frame moves so that the hoop bars are aligned with the main bars arranged on the main bar prepositioning unit. At this time, the welding motion bracket controls the movement of the mover of the multi-moving slide table to position the second conveying bracket adjacent to the main bar prepositioning unit and moves the second conveying bracket towards the middle. At the same time, the rollers of the second conveying bracket are controlled to adjust the horizontal and vertical spacing between them so that the rollers of the second conveying bracket are aligned with the rollers of the first conveying bracket. S4. The main reinforcement prepositioning unit transports the main reinforcement to the welding motion support, so that the main reinforcement is inserted into the hoop reinforcement assembly. The roller spacing on the second conveying support is controlled again to make each main reinforcement contact each node of the hoop reinforcement. At this time, the main reinforcement has been inserted into the hoop reinforcement, forming a preliminary structure of a steel truss on the welding motion support. Then the arrangement frame moves back to the original point and begins the hoop reinforcement loading and pre-arrangement of the next steel truss. S5. The welding motion support starts to move towards the four-sided welding unit. The vision sensor on the four-sided welding unit identifies the spatial position of the steel truss welding node and starts to automatically identify the welding. When the first conveying support on the welding motion support moves to the point where it is about to interfere with the rectangular frame, it will automatically adjust the height of the rollers to make the rollers disengage from the main reinforcement. Then, it will move back to the origin in the direction away from the steel truss through the third linear guide rail until it misses the rectangular frame. Then, it will move in the opposite direction and make the rollers contact the main reinforcement again to support the welded part from the bottom of the main reinforcement until the entire steel truss is welded. S6. The area for manual inspection is where materials are sent for testing. After manual inspection, the materials can be stored in the warehouse or directly loaded onto trucks.

[0014] As described above, the features and advantages of the automated steel truss production line of the present invention are as follows: This application integrates processes such as vibration paving, equidistant conveying, piercing and tapping, automatic material classification and storage, main reinforcement pre-positioning, hoop forming, automatic hoop feeding and arrangement, welding motion support insertion, and four-sided welding into a single automated production line. This constructs a steel truss production system with automated material conveying as its main line. The production line employs various transportation or storage devices, including a first conveyor, roller conveyor sets, a vertical elevator, a second conveyor, and a traversing guide rail for the arrangement frame. This achieves a truss machine that integrates intelligent sorting, feeding, tapping, straightening, CNC bending, welding, and inspection. Compared to existing technologies that rely on manual arrangement of hoop reinforcement and on-site welding, this application significantly reduces manual intervention through automated material flow, addressing the pain point of high labor costs. Furthermore, since each process is precisely controlled by a CNC system, dimensional deviations and unstable welding quality caused by manual operation are avoided, effectively solving the problem of inconsistent quality in existing on-site construction processes and ensuring the consistency and reliability of steel truss products.

[0015] To address the shortcomings of existing technologies where mechanical bending and assembly / welding equipment are scattered and lack systematic connection, resulting in low production efficiency, this application constructs a fully automated conveyor line from main reinforcement processing to hoop forming and truss welding through the sequential connection and coordinated operation of a main reinforcement pretreatment unit, a main reinforcement material storage unit, a main reinforcement prepositioning unit, a hoop forming unit, a hoop loading unit, a welding motion support, and a four-sided welding unit. In this production line, a vibrating paver, a first conveyor, a roller conveyor wheel set, a vertical lift, a material rack, a second conveyor, an arrangement rack, and a fifth linear guide rail at its bottom, among other conveying and storage devices, achieve automatic transfer, equidistant conveying, vertical lifting, and horizontal alignment of materials such as steel bars, main reinforcement, and hoop between various workstations. This forms an automated steel truss production line and its production process, primarily applied to beam and column assembly in prefabricated building construction. This production line integrates the previously scattered bending, arrangement, assembly, and welding processes into one, and solves the inefficiency problem caused by the scattered process flow through the orderly connection of the material conveying system, significantly improving the production efficiency of steel trusses. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall layout of the automated steel truss production line shown in this invention; Figure 2 for Figure 1 A schematic diagram of part A on one side of the XX dividing line; Figure 3 for Figure 1 Schematic diagram of part B on the other side of the XX dividing line; Figure 4 for Figure 3 Enlarged structural diagram at point D; Figure 5 for Figure 3 Enlarged structural diagram at point E; Figure 6 This is a schematic diagram showing the cooperation between the welding motion support and the hoop feeding unit of the automated steel truss production line of the present invention; Figure 7 for Figure 6 Another perspective diagram of the structure; Figure 8 for Figure 2 Enlarged structural diagram at point C; Figure 9 This is a schematic diagram of the welding motion support and four-sided welding unit of the automated steel truss production line shown in this invention; Figure 10 This is a schematic diagram of the welding motion support and main reinforcement of the automated steel truss production line shown in this invention; Figure 11 for Figure 10 Enlarged structural diagram at point F; Figure 12 This is a process flow diagram of the automated steel truss production line shown in this invention.

[0017] The reference numerals in the accompanying drawings of this invention are as follows: Main reinforcement pretreatment unit: 11. Vibratory paving machine; 12. First conveyor; 13. Upsetting machine; 14. Tapping machine; 15. First linear guide rail; Main reinforcement material storage unit: 21. Double roller conveyor wheel set; 211. Second linear guide rail; 22. Vertical elevator; 23. Material rack; Welding motion support: 41. Multi-movement slide table; 42. Third linear guide rail; Four-sided welding unit: 31. Rectangular frame; 32. Sixth linear guide rail; 33. Welding robot; Main support frame: 51. Lead screw guide rail; 511. Nut slider; 52. Screw guide rail; 521. Screw slider; 53. Sliding shaft; 54. Roller; 55. Spring; 56. Motor 1; 57. Motor 2; 58. Motor 3; Hoop forming unit: 61. Rebar straightening machine; 62. CNC bending machine; 63. Resistance welding equipment; Enclosure feeding unit: 71, Second conveyor; 72, Groove clamp; 73, Fourth linear guide rail; 74, Third conveyor; 75, Push hook; 76, Arrangement rack; 77, Fifth linear guide rail; 78, Crossbeam; 79, Groove. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0019] See Figures 1-12 As shown, an embodiment of the present invention is provided, and its process flow will be described in detail below: An automated production line for steel trusses includes: See Figures 1-4As shown, the main reinforcement pretreatment unit includes a vibratory paving machine 11, a first conveyor 12 for equidistantly conveying the main reinforcement bars, and an end processing device for upsetting and tapping the ends of the main reinforcement bars. The first conveyor 12 and the vibratory paving machine 11 are arranged side by side, and the end processing devices are located at both ends of the first conveyor 12. The vibratory paving machine 11 disperses bundles of steel bars and arranges them into a single layer through a vibrating platform. At the same time, it uses a rotating end alignment mechanism to align one end of the steel bars. This is existing technology and will not be described in detail here. The first conveyor 12 adopts an intermittent feeding method. During the feeding stop period, the end processing device processes both ends of the steel bars to ensure processing accuracy. Furthermore, each time the feeding stops, there should be a working end of the main reinforcement alignment end processing device.

[0020] See Figures 3-4 As shown, the main reinforcement storage unit includes a roller conveyor 21 for receiving and horizontally transferring the main reinforcement, a vertical elevator 22 for vertically lifting the main reinforcement, and a rack 23 for storing the main reinforcement according to specifications. The vertical elevator 22 and the rack 23 are arranged side by side. The roller conveyor 21 is located at the outlet of the first conveyor 12 and aligned with the vertical elevator 22. The roller conveyor 21 consists of two rollers 54 facing each other. Driven by a servo motor, the rollers are pushed horizontally from the outlet of the first conveyor 12 to the inlet of the vertical elevator 22 by friction. The vertical elevator 22 uses a chain or screw lifting mechanism to lift the main reinforcement to different heights on the rack 23. The rack 23 has a multi-layer structure, with each layer corresponding to a storage area for a specific specification of main reinforcement. The above equipment is conventional technology in the field, and the specific structure will not be described in detail here.

[0021] See Figure 3 and Figure 5 As shown, the main rib pre-positioning unit includes a first conveying bracket capable of adjusting the spacing of the main ribs, and a third material handling robot for transferring the main ribs one by one from the material rack 23 to the first conveying bracket. The first conveying bracket is located on the side of the material rack 23 away from the vertical elevator 22. The first conveying bracket is equipped with multiple main rib supports with independently adjustable horizontal and vertical spacing to adapt to the main rib arrangement requirements of different truss specifications. The third material handling robot can be a rectangular coordinate guide rail robot, a robot integrated into the telescopic end of a telescopic cylinder (electric cylinder, pneumatic cylinder, or hydraulic cylinder), an articulated robot arm, or other types of existing technologies. Its end is equipped with a mechanical gripper for taking out a single main rib from the material rack 23 and placing it in the corresponding position on the first conveying bracket. The material handling robot equipment is conventional technology in this field, and its specific structure will not be described in detail here.

[0022] See Figure 2 As shown, the hoop forming unit is used to bend and weld steel bars into hoops. This unit sequentially straightens, CNC bends, and resistance welds the coiled steel bars to form a closed hoop component.

[0023] See Figure 2 and Figures 6-8 As shown, the hoop feeding unit includes a second conveyor 71 for conveying hoops, an arranging frame 76 for neatly arranging hoops, and a pushing mechanism for pushing the hoops one by one from the second conveyor 71 into the arranging frame 76. The arranging frame 76 is arranged side by side on one side of the second conveyor 71, and the pushing mechanism is arranged on the side of the arranging frame 76 away from the second conveyor 71. A fifth linear guide rail 77 is provided at the bottom of the arranging frame 76, which can move the arranging frame 76 as a whole to be aligned with one end of the first conveying support.

[0024] See Figures 9-10 As shown, the welding motion support includes a multi-moving sub-slide 41, a third linear guide 42 fixedly installed on the top of each slide, and a second conveying support fixedly installed on the top of the slider of the third linear guide 42. Both the first and second conveying supports include multiple main rib supports. The multi-moving sub-slide 41 is arranged parallel to the arranging frame 76 and is located on the side away from the second conveyor 71. When the arranging frame 76 is translated and aligned with the first conveying support, the slider of the third linear guide 42 can drive the second conveying support to translate, so that the multiple main rib supports it includes are inserted into the gaps between the multiple hoops in the arranging frame 76. Each mover of the multi-moving sub-slide 41 can be controlled independently or as a whole to realize the step feeding of the second conveying support. The third linear guide 42 is used to adjust the relative position between the second conveying support and the first conveying support so that the main rib supports can be accurately inserted into the gaps between the hoops.

[0025] See Figure 9 As shown, the four-sided welding unit is located at one end of the arrangement frame 76 away from the first conveying support and on one side of the multi-moving sub-slide table 41, and is used to weld the steel truss after the main reinforcement and the hoop are combined.

[0026] Furthermore, the main reinforcement pretreatment unit also includes a first material handling robot, used to transfer the orderly arranged main reinforcement bars from the vibratory paving machine 11 to the first conveyor 12 one by one. The end processing device includes two upsetting machines 13 and two tapping machines 14. The bottom of the upsetting machine 13 and the tapping machine 14 are provided with a first linear guide rail 15, used to push the working ends of the upsetting machine 13 and the tapping machine 14 toward the end of the main reinforcement bar. The first material handling robot can be a rectangular coordinate guide rail type robot or a robot integrated into the extension end of a telescopic cylinder (electric cylinder, pneumatic cylinder or hydraulic cylinder). The movement of the articulated robotic arm or other existing technologies is controlled by a PLC and synchronized with the intermittent feeding rhythm of the first conveyor 12. The upsetting machine 13 upsets the end of the steel bar to a predetermined diameter by hydraulic or mechanical means. The tapping machine 14 processes the external thread on the upset part. The external thread is matched with the thread sleeve, which facilitates the splicing of multiple trusses in actual use. Both are conventional equipment in this field, and the specific internal structure will not be described in detail here. The first linear guide 15 is driven by a cylinder or servo motor to ensure the precise alignment of the processing end and the end of the steel bar.

[0027] Furthermore, the roller conveyor wheel set 21 consists of two sets, respectively located at both ends of the discharge port of the first conveyor 12. A second linear guide rail 211 is provided at the bottom of the roller conveyor wheel set 21 to push the roller conveyor wheel set 21, causing its rollers to contact the two ends of the main rib, so that the main rib enters the gap between the rollers of the roller conveyor wheel set 21. The main rib storage unit also includes a second material handling robot that transfers the main rib from the vertical elevator 22 to the material rack 23. The second material handling robot can be a rectangular coordinate guide rail robot, a robot integrated into the telescopic end of a telescopic cylinder (electric cylinder, pneumatic cylinder, or hydraulic cylinder), an articulated robot arm, or other existing technologies. The two sets of roller conveyor wheel sets 21 correspond to the two ends of the main rib, and the second linear guide rail 211 drives the entire... The roller set moves towards the main reinforcement bar, causing the upper and lower rollers to press the ends of the main reinforcement bar tightly. The rollers have a rubber or polyurethane layer on their surface to increase friction and prevent scratching the reinforcement bar, which is a conventional technology. After the main reinforcement bar is clamped, the rollers rotate under the drive of a servo motor, pushing the main reinforcement bar horizontally to the entrance of the vertical elevator 22. One specific implementation is as follows: First, both sets of roller conveyor sets 21 move towards the two ends of the main reinforcement bar, and during continuous feeding, feed the two ends of the main reinforcement bar into the space between the rollers inside the roller conveyor sets 21. Then, the two sets of roller conveyor sets 21 drive the main reinforcement bar to move as a whole towards the entrance of the vertical elevator 22. After alignment, the two sets of roller conveyor sets 21 continue to convey the main reinforcement bar towards the vertical elevator 22 until the main reinforcement bar is completely sent into the vertical elevator 22.

[0028] For further details, please refer to [link / reference]. Figures 9-11As shown, the main support frame includes an upright lead screw guide rail 51, a nut slider 511 fitted inside the lead screw guide rail 51, the nut slider 511 including multiple first slide plates slidably fitted inside the lead screw guide rail 51, a nut rotatably connected inside the first slide plate, the nut being threadedly connected to the lead screw inside the lead screw guide rail 51, the lead screw being fixedly connected to the guide rail body of the lead screw guide rail 51, and also includes multiple screw guide rails 52 corresponding to the height of each first slide plate, the screw guide rails 52 are all horizontally arranged, a screw slider 521 fitted inside the screw guide rail 52, the screw slider 521 including a second slide plate slidably fitted inside the screw guide rail 52, a screw rotatably connected to one end of the second slide plate, the screw being threadedly connected to one end of the screw guide rail 52, the second slide plate being fixedly connected to the first slide plate.

[0029] The main support also includes a sliding shaft 53 rotatably connected to the end of the second slide away from the screw. The sliding shaft 53 passes through the end of the screw guide rail 52 away from the screw and extends outward. Multiple rollers 54 are sleeved on the outside of the extended section of the sliding shaft 53. The outermost roller 54 is fixedly connected to the sliding shaft 53, and the remaining rollers 54 slide and cooperate with the outside of the sliding shaft 53. Springs 55 are sleeved on the outside of the sliding shaft 53 between adjacent rollers 54.

[0030] The main rib support also includes motor 56, motor 57 and motor 58 fixedly installed on each of the second slide plates. Among them, motor 56 is used to drive the nut to rotate, motor 57 is used to drive the screw to rotate, and motor 58 is used to drive the sliding shaft 53 to rotate. Motors 56, 57 and 58 are all servo motors, and the control system automatically adjusts the speed and direction according to the truss specification parameters to realize the rapid adjustment and conveying of the main rib spacing.

[0031] The first conveying support includes multiple main rib supports arranged in parallel at equal intervals. In the second conveying support, the bottom of each lead screw guide rail 51 is fixedly installed on the top of the slider of each third linear guide rail 42. The main rib supports on the second conveying support can move independently with the slider of the third linear guide rail 42 so as to adjust the support position during the welding process.

[0032] The working principle of the main rib support is as follows: the screw guide rail 51 is installed vertically, and the nut is driven to rotate by the motor 56. Under the guidance and restriction of the guide rail body, the nut drives the first slide plate and the second slide plate fixedly connected to it to move in the vertical direction. The second slide plate drives the guide rail body of the screw guide rail 52 to move, thereby adjusting the vertical position of the roller 54 by the lifting and lowering of the sliding shaft 53. The screw is driven to rotate by the motor 57. Under the guidance and restriction of the second slide plate, the guide rail body of the screw guide rail 52 moves horizontally relative to the second slide plate, thereby squeezing the adjacent roller 54 on the sliding shaft 53. When the roller 54 is pushed on the sliding shaft 53, it will synchronously compress each spring 55 through the transmission of force, thereby adjusting the lateral (horizontal) distance between the rollers 54. The motor 58 drives the sliding shaft 53 to rotate. Due to the mechanical transmission characteristics of the sliding engagement, it can drive all the rollers 54 on the entire sliding shaft 53 to rotate, thereby driving the main rib to move.

[0033] The driving force of the above-mentioned motors is preferably transmitted through gear pairs, which is a conventional technology and will not be shown in detail here. It should be noted that the motor 56 is used to drive the nut to rotate, and a worm gear drive is preferred. It has a certain self-locking ability and can stabilize the height of the main rib. Specifically, the worm gear is fixedly mounted on the outside of the nut, and the worm is connected to the motor 56. The worm drives the worm gear to drive the nut to rotate. This is a conventional technology and will not be shown in detail here.

[0034] For further details, please refer to [link / reference]. Figure 2 As shown, the hoop forming unit includes a rebar straightening machine 61, a CNC bending machine 62 located at one end of the rebar straightening machine 61, the CNC bending machine 62 being used to bend rebars to form circumferential bars and stirrups, and a resistance welding device 63 located at one end of the CNC bending machine 62 being used to weld the circumferential bars and stirrups together to form a hoop. The rebar straightening machine 61 straightens the coiled rebars through multiple sets of straightening rollers, and uses traction wheels (the mechanism principle is the same as that of the double roller conveyor wheel set 21) to feed the rebars into the CNC bending machine 62. The CNC bending machine 62 bends the rebars into shape according to preset parameters. The resistance welding device 63 welds the open end of the circumferential bars to the end of the stirrups using butt welding or spot welding to form a complete hoop component. During welding, the hoop bars are rotated by a phase conversion machine to weld each part. The specific structure and working principle of the above equipment are existing technologies and will not be described in detail here.

[0035] Furthermore, the hoop loading unit includes a fourth material handling robot that transfers the hoop from the resistance welding equipment 63 to the second conveyor 71. The second conveyor 71 is a chain conveyor, with multiple slotted clamps 72 evenly and fixedly connected around the chain. When the slotted clamps 72 move above the second conveyor 71, their slots point directly upwards, ensuring that the hoop inside the slotted clamps 72 is in an upright conveying state. The fourth material handling robot can be a rectangular coordinate guide rail robot, a robot integrated into the telescopic end of a telescopic cylinder (electric cylinder, pneumatic cylinder, or hydraulic cylinder), an articulated robot arm, or other existing technologies. It transfers the welded hoop from the discharge port of the resistance welding equipment 63 to the slotted clamps 72 of the second conveyor 71. The shape of the slotted clamps 72 matches the bottom contour of the hoop, ensuring that the hoop remains stable and upright during conveying.

[0036] The pushing mechanism includes a fourth linear guide rail 73 parallel to the second conveyor 71, and a third conveyor 74 fixedly installed on the top of the slider of the fourth linear guide rail 73. The third conveyor 74 is a single-chain conveyor (its operating mechanism is analogous to a chain drive pair). The slider of the fourth linear guide rail 73 moves in a direction perpendicular to the rotation plane of the chain of the third conveyor 74. A push hook 75 is fixedly connected to the side of the chain of the third conveyor 74. When the chain of the third conveyor 74 drives the push hook 75 towards the second conveyor 71... During movement, the retaining hoops in the slot clamp 72 can be pushed into the arranging frame 76. Specifically, when the push hook 75 moves with the chain, it pushes the retaining hoop from the side away from the arranging frame 76, pushing the retaining hoop out of the slot clamp 72 and into the slot 79 of the arranging frame 76. In one specific implementation, when the third conveyor 74 is conveyed by the fourth linear guide rail 73, it pushes the retaining hoops into the slot 79 one by one, starting from the farthest retaining hoop. The second conveyor 71 should remain stationary after the slot clamp 72 is aligned with the slot 79.

[0037] The slider movement direction of the fifth linear guide 77 is perpendicular to the movement direction of the mover of the multi-moving slide table 41. The interior of the arranging frame 76 is equipped with crossbeams 78 at both the upper and lower sides. Multiple slots 79 (which can be made directly from angle steel) are evenly fixedly connected along the length of the opposite sides of the crossbeams 78. The spacing between the upper and lower slots 79 is consistent with the height of the hoop when it is upright, and the slot openings are opposite each other. When the slot clamp 72 moves to align with a certain slot 79, the hoop inside it can be pushed into the slot 79 by the pushing mechanism. The fifth linear guide 77 at the bottom of the arranging frame 76 drives the entire arranging frame 76 to move laterally, so that one end of the slot 79 aligns with the slot clamp 79 on the second conveyor 71. 2. The grooves 79 are aligned closely to facilitate the pushing and transfer of the hoop between them. The depth and width of the grooves 79 are slightly larger than the cross-sectional dimensions of the hoop to ensure that the hoop can slide in smoothly and maintain an upright posture. Multiple grooves 79 are evenly distributed. It should be noted that the arrangement density of the grooves 79 should be relatively high to accommodate the arrangement requirements of hoops with different densities. If the density is low, the hoop will be pushed into only a few grooves 79, and vice versa. Furthermore, the upper crossbeam 78 should have a height adjustment mechanism, such as adjustment by a screw, which is an existing technology, so as to meet the stable arrangement requirements of hoops with different heights.

[0038] Furthermore, the four-sided welding unit includes an upright rectangular frame 31, which is located at the end of the arrangement frame 76 away from the first conveying support and on one side of the multi-moving sub-slide table 41. The opening of the rectangular frame 31 is aligned with the first conveying support. Sixth linear guides 32 are fixedly installed on all four sides of the rectangular frame 31 along its length. Welding robots 33 are fixedly installed on the sliders of the sixth linear guides 32. Visual recognition sensors are also provided on the rectangular frame 31 to identify the spatial position of the welding nodes. The rectangular frame 31 is made of high-strength steel structure, and the size of the opening matches the cross-section of the truss. The sixth linear guides 32 are used to adjust the position of the welding robots 33 on the four sides of the frame to adapt to the distribution of welding nodes of different truss specifications. The visual recognition sensors are industrial cameras combined with structured light or laser ranging modules, which can acquire the three-dimensional coordinates of the truss nodes in real time. The control system drives the welding robots 33 to perform precise welding based on these coordinates. The cooperation between the visual recognition sensors and the welding robots 33 is a well-known technology in the field and will not be described in detail here.

[0039] For further details, please refer to [link / reference]. Figure 12 As shown, this embodiment also provides a process flow based on the above-mentioned automated production line for steel trusses, including the following steps: S1. After the vibratory paving machine 11 aligns the main ribs, it transfers them to the first conveyor 12 for horizontal equidistant feeding. During feeding, it adopts an intermittent stopping method, and during the stopping, it performs upsetting and tapping on both ends of the main ribs to achieve pre-treatment. Then, the vertical elevator 22 sorts the treated main ribs into the material rack 23 according to their specifications. The feeding interval stopping time is set by the control system according to the processing time required for upsetting and tapping to ensure that the processing of both ends of each main rib is completely consistent. After the vertical elevator 22 lifts the main ribs to the corresponding specification of the material rack 23, they are sent into that layer for storage.

[0040] S2. Based on the required dimensions of the steel truss to be produced, parameters are pre-set to control the rollers 54 in the main reinforcement prefabrication unit, adjusting their lateral and vertical spacing to achieve the set spacing. A third material handling robot then transfers the main reinforcement bars of different specifications from the material rack 23 to the first conveying support one by one. The control system automatically calculates the lateral and vertical spacing between the main reinforcement bars based on the input truss model and drives motors 56 and 57 on the main reinforcement support to adjust to the target positions. The third material handling robot sequentially removes the main reinforcement bars from the material rack 23 and places them onto the corresponding rollers 54 on the first conveying support.

[0041] S3. The hoop loading unit arranges the bent hoop bars according to the required spacing, and then transfers the arranged hoop bars to the arranging frame 76. The arranging frame 76 moves to align the hoop bars with the main bars already arranged on the main bar pre-positioning unit. At this time, the welding motion bracket controls the movement of the mover of the multi-moving slide 41 to position the second conveying bracket adjacent to the main bar pre-positioning unit and moves the second conveying bracket towards the center. At the same time, the rollers 54 of the second conveying bracket are controlled to adjust their lateral and vertical spacing to allow the second conveying bracket to move more smoothly. The rollers 54 of the support are aligned with the rollers 54 of the first conveying support. The arranging frame 76 moves along the fifth linear guide rail 77 so that its groove 79 is aligned with the main reinforcement support of the first conveying support (the whole is on the same straight line). The multi-moving sub-slide 41 drives the second conveying support to move to one end of the first conveying support so that the main reinforcement supports of the two correspond one-to-one. The motors 56 and 57 on the second conveying support adjust the position of the rollers 54 so that they are at the same horizontal height and lateral coordinate as the rollers 54 of the first conveying support, so that the subsequent main reinforcement can be smoothly inserted into the hoop.

[0042] S4. The main reinforcement pre-positioning unit conveys the main reinforcement to the welding motion support, allowing the main reinforcement to penetrate into the hoop reinforcement assembly. The spacing of the rollers 54 on the second conveying support is controlled again to ensure that each main reinforcement contacts each node of the hoop reinforcement. At this point, the main reinforcement has been inserted into the hoop reinforcement, forming a preliminary structure of a steel truss on the welding motion support. Then, the arranging frame 76 retracts back to its original position and begins the pre-arrangement of the hoop reinforcement for the next steel truss. The rollers 54 on the first conveying support rotate under the drive of the motor 58, pushing the main reinforcement forward and passing through the hoop reinforcements already arranged on the arranging frame 76 in sequence. When the main reinforcement reaches the position of the rollers 54 on the second conveying support, the rollers 54 on the second conveying support rotate synchronously, continuing to pull the main reinforcement forward until it is completely inserted into all the hoop reinforcements. At this point, each hoop reinforcement is located at the designated node position of the main reinforcement. Subsequently, the arranging frame 76 retracts to its original position along the fifth linear guide rail 77 and begins to receive the next set of hoop reinforcements, achieving continuous operation.

[0043] S5. The welding motion support begins to move towards the four-sided welding unit. The vision sensors on the four-sided welding unit identify the spatial position of the steel truss welding node and begin automatic welding. When the second conveyor on the welding motion support is about to interfere with the rectangular frame 31, it automatically adjusts the height of the roller 54 (lowering it to disengage from the main reinforcement), causing the roller 54 to disengage from the main reinforcement. It then moves back to its original position away from the steel truss via the third linear guide 42 until it misses the rectangular frame 31. It then moves in the opposite direction, causing the roller 54 to re-engage with the main reinforcement and support the welded portion from the bottom of the main reinforcement until the entire steel truss is welded. The multi-moving sub-slide 41 of the welding motion support drives... The second conveying support and the main truss step towards the four-sided welding unit. The vision sensor detects the node position in real time. The welding robot 33 welds each node in sequence. When the second conveying support approaches the rectangular frame 31, the roller 54 on its main truss support is lowered by the motor 56 and disengaged from the main truss. At the same time, the third linear guide rail 42 moves the second conveying support backward (away from the rectangular frame 31) so that the welded part passes through the rectangular frame 31. After the second conveying support has completely passed the rectangular frame 31, it moves in the opposite direction and raises the roller 54 to support the main truss again and continues to convey and weld forward. This process is repeated until the entire truss has completely passed through the four-sided welding unit and all nodes are welded.

[0044] S6. After welding is completed, the products can be temporarily stored on the plate chain conveyor belt and sent to the manual inspection area. After manual inspection, qualified products can be placed in the warehouse or directly loaded onto the truck. Unqualified products are repaired by manual welding. When shipping, a visual recognition loading device is used to reduce labor consumption and improve automation efficiency. This device is a well-known technology in this field and will not be described in detail here.

[0045] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0046] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An automated production line for steel trusses, characterized in that, include: The main reinforcement pretreatment unit includes a vibratory paving machine (11), a first conveyor (12) for equidistantly conveying the main reinforcement, and an end processing device for upsetting and tapping the ends of the main reinforcement. The first conveyor (12) is arranged in parallel with the vibratory paving machine (11), and the end processing device is located at both ends of the first conveyor (12). The main reinforcement storage unit includes a roller conveyor (21) for receiving the main reinforcement and transferring it horizontally, a vertical elevator (22) for vertically lifting the main reinforcement, and a rack (23) for storing the main reinforcement according to specifications. The vertical elevator (22) and the rack (23) are arranged side by side, and the roller conveyor (21) is located at the outlet of the first conveyor (12) and aligned with the vertical elevator (22). The main rib pre-positioning unit includes a first conveying bracket capable of adjusting the spacing of the main ribs, and a third material handling robot for transferring the main ribs one by one from the material rack (23) to the first conveying bracket. The first conveying bracket is located on the side of the material rack (23) away from the vertical elevator (22). The hoop forming unit is used to bend and weld steel bars into hoops; The hoop feeding unit includes a second conveyor (71) for conveying hoops, an arrangement frame (76) for neatly arranging hoops, and a pushing mechanism for pushing the hoops one by one from the second conveyor (71) into the arrangement frame (76). The arrangement frame (76) is arranged side by side on one side of the second conveyor (71), and the pushing mechanism is arranged on the side of the arrangement frame (76) away from the second conveyor (71). A fifth linear guide rail (77) is provided at the bottom of the arrangement frame (76) to be able to move the arrangement frame (76) as a whole to be aligned with one end of the first conveyor support. The welding motion support includes a multi-moving sub-slide (41), a third linear guide (42) fixedly installed on the top of each slide, and a second conveying support fixedly installed on the top of the slider of the third linear guide (42). Both the first and second conveying supports include multiple main rib supports. The multi-moving sub-slide (41) is arranged parallel to the arranging frame (76) and is located on the side away from the second conveyor (71). When the arranging frame (76) is translated and aligned with the first conveying support, the slider of the third linear guide (42) can drive the second conveying support to translate, so that the multiple main rib supports included therein are inserted into the gap between the multiple hoops in the arranging frame (76). The four-sided welding unit is located at one end of the arrangement frame (76) away from the first conveying support and on one side of the multi-moving sub-slide table (41) for welding the steel truss after the main reinforcement and the hoop are combined.

2. The automated production line for steel trusses according to claim 1, characterized in that: The main reinforcement pretreatment unit also includes a first material handling robot, which is used to transfer the orderly arranged main reinforcement from the vibratory paving machine (11) to the first conveyor (12) one by one. The end processing device includes two upsetting machines (13) and two tapping machines (14). The bottom of the upsetting machine (13) and the tapping machine (14) are provided with a first linear guide rail (15), which is used to push the working end of the upsetting machine (13) and the tapping machine (14) to the end of the main reinforcement.

3. The automated production line for steel trusses according to claim 1, characterized in that: There are two sets of roller conveyor wheel sets (21), which are respectively set at both ends of the discharge port of the first conveyor (12). The bottom of the roller conveyor wheel set (21) is provided with a second linear guide rail (211) for pushing the roller conveyor wheel set (21) so that its rollers contact the two ends of the main rib, so that the main rib enters the gap between the rollers of the roller conveyor wheel set (21). The main reinforcement material storage unit also includes a second material handling robot that transfers the main reinforcement from the vertical elevator (22) to the material rack (23).

4. The automated production line for steel trusses according to claim 1, characterized in that: The main support includes a vertically mounted screw guide rail (51), a nut slider (511) fitted inside the screw guide rail (51), the nut slider (511) includes multiple first slide plates slidably fitted inside the screw guide rail (51), a nut rotatably connected inside the first slide plate, the nut being threadedly connected to the screw inside the screw guide rail (51), and multiple screw guide rails (52) corresponding to the height of each first slide plate. The screw guide rails (52) are all horizontally arranged, and a screw slider (521) fitted inside the screw guide rail (52) includes a second slide plate slidably fitted inside the screw guide rail (52), a screw rotatably connected to one end of the second slide plate, the screw being threadedly connected to one end of the screw guide rail (52), and the second slide plate being fixedly connected to the first slide plate. The main support also includes a sliding shaft (53) rotatably connected to the end of the second slide away from the screw. The sliding shaft (53) passes through the end of the screw guide rail (52) away from the screw and extends outward. Multiple rollers (54) are sleeved on the outside of the extended section of the sliding shaft (53). The outermost roller (54) is fixedly connected to the sliding shaft (53), and the remaining rollers (54) slide with the outside of the sliding shaft (53). Springs (55) are sleeved on the outside of the sliding shaft (53) between adjacent rollers (54). The main support frame also includes motor one (56), motor two (57) and motor three (58) fixedly installed on each of the second slide plates. Among them, motor one (56) is used to drive the nut to rotate, motor two (57) is used to drive the screw to rotate, and motor three (58) is used to drive the sliding shaft (53) to rotate. The first conveying bracket includes multiple main rib brackets arranged at equal intervals in parallel. In the second conveying bracket, the bottom of each screw guide rail (51) is fixedly installed on the top of the slider of each third linear guide rail (42).

5. The automated production line for steel trusses according to claim 1, characterized in that: The hoop forming unit includes a steel bar straightening machine (61), a CNC bending machine (62) located at one end of the steel bar straightening machine (61), the CNC bending machine (62) being used to bend steel bars to form hoop bars and stirrups, and a resistance welding device (63) located at one end of the CNC bending machine (62) being used to weld the hoop bars and stirrups together to form a hoop.

6. The automated production line for steel trusses according to claim 1, characterized in that: The hoop loading unit includes a fourth material handling robot that transfers the hoop from the resistance welding equipment (63) to the second conveyor (71). The second conveyor (71) is a chain conveyor, with multiple slot clamps (72) evenly and fixedly connected around the chain. When the slot clamp (72) moves above the second conveyor (71), its slot opening points directly upward, so that the hoop inside the slot clamp (72) is in an upright conveying state. The pushing mechanism includes a fourth linear guide rail (73) set parallel to the second conveyor (71), and a third conveyor (74) fixedly installed on the top of the slider of the fourth linear guide rail (73). The third conveyor (74) is a single-chain conveyor. The slider of the fourth linear guide rail (73) moves perpendicular to the chain rotation surface of the third conveyor (74). A push hook (75) is fixedly connected to the side of the chain of the third conveyor (74). When the chain of the third conveyor (74) drives the push hook (75) to move towards the second conveyor (71), it can push the hoops in the slot clamp (72) into the arrangement frame (76). The slider movement direction of the fifth linear guide (77) is perpendicular to the movement direction of the mover of the multi-mover slide (41). The upper and lower sides of the arrangement frame (76) are provided with crossbeams (78). Multiple slots (79) are uniformly fixedly connected on the opposite sides of the crossbeams (78) along their length direction. The distance between the upper and lower slots (79) is consistent with the height of the hoop when it is upright, and the slot openings are opposite each other. When the slot clamp (72) moves to align with a certain slot (79), the hoop inside it can be pushed into the slot (79) by the pushing mechanism.

7. The automated production line for steel trusses according to claim 1, characterized in that: The four-sided welding unit includes an upright rectangular frame (31). The rectangular frame (31) is located at one end of the arrangement frame (76) away from the first conveying support and on one side of the multi-moving sub-slide table (41). The frame opening of the rectangular frame (31) is aligned with the first conveying support. Sixth linear guides (32) are fixedly installed on all four sides of the rectangular frame (31) along its length direction. Welding robots (33) are fixedly installed on the sliders of the sixth linear guides (32). Visual recognition sensors are also provided on the rectangular frame (31) to identify the spatial position of the welding nodes.

8. The process flow of an automated production line for steel trusses according to any one of claims 1-7, characterized in that: Includes the following steps: S1. After the vibrating paving machine (11) aligns the main reinforcement bars, it transfers the main reinforcement bars to the first conveyor (12) for horizontal equidistant feeding. During feeding, it adopts an intermittent stopping method, and when stopping, it performs pre-treatment by thickening and tapping the two ends of the main reinforcement bars. Then, it uses a vertical lifting machine (22) to classify the treated main reinforcement bars into the material rack (23) according to specifications. S2. Based on the required steel truss dimensions, pre-set parameters to control the rollers (54) in the main reinforcement pre-set unit, so that the horizontal and vertical spacing between them can be adjusted, thereby achieving the setting of the spacing. The third material handling robot will transfer the main reinforcement of beams and columns of different specifications from the material rack (23) to the first conveying support one by one. S3. The hoop loading unit arranges the bent hoop bars according to the required spacing, and then transfers the arranged hoop bars to the arrangement frame (76). The arrangement frame (76) moves so that the hoop bars are aligned with the main bars arranged on the main bar prepositioning unit. At this time, the welding motion support controls the movement of the mover of the multi-moving slide (41) so that the second conveying support can be positioned adjacent to the main bar prepositioning unit and the second conveying support is moved towards the middle. At the same time, the rollers (54) of the second conveying support are controlled so that the horizontal and vertical spacing between them is adjusted so that the rollers (54) of the second conveying support are aligned with the rollers (54) of the first conveying support. S4. The main reinforcement prepositioning unit transports the main reinforcement to the welding motion support, so that the main reinforcement is inserted into the hoop reinforcement assembly. The distance between the rollers (54) on the second conveying support is controlled again so that each main reinforcement is in contact with each node of the hoop reinforcement. At this time, the main reinforcement has been inserted into the hoop reinforcement, forming a preliminary structure of a steel truss on the welding motion support. Then the arrangement frame (76) moves back to the original point and begins the hoop reinforcement loading and pre-arrangement of the next steel truss. S5. The welding motion support starts to move towards the four-sided welding unit. The visual sensor on the four-sided welding unit identifies the spatial position of the steel truss welding node and starts to automatically identify the welding. When the first conveying support on the welding motion support moves to the point where it is about to interfere with the rectangular frame (31), it will automatically adjust the height of the roller (54) so ​​that the roller (54) is out of contact with the main bar. It will then move back to the origin in the direction away from the steel truss through the third linear guide rail (42) until it misses the rectangular frame (31) and moves in the opposite direction. Then the roller (54) will contact the main bar again and support the part that has been welded from the bottom of the main bar until the entire steel truss is welded. S6. The sample is sent to the manual inspection area. After manual inspection, it can be placed in the warehouse or directly loaded onto the truck.

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