Method for assembling front foot ladder of metal herringbone ladder

Abstract

The invention discloses a method for assembling a front foot ladder of a metal herringbone ladder, which adopts a device for assembling the front foot ladder of the metal herringbone ladder for assembling, and specifically comprises the following steps of: horizontally transferring a ladder tube to the front of a horizontal drilling station through a ladder tube feeding mechanism, and overturning the ladder tube at a conveying tail end to a vertical state; the first manipulator is used for transferring the ladder pipe into the ladder pipe limiting seat, and drilling and tapping or / and punching are / is carried out through the horizontal drilling mechanism; the foot sleeves are jacked in from the ladder pipes through the foot sleeve mounting mechanism, external force is applied to preset positions of the ladder pipes through the extrusion deformation mechanism for extrusion, and the ladder pipes are locally sunken and deformed; the ladder pipes are grabbed by a second manipulator, inclined and steered and placed on the front foot ladder limiting jig in a splayed shape, and a cross rod and a top pedal are placed between the two ladder pipes; and the whole front foot ladder limiting jig is transferred to a vertical drilling and tapping station for drilling and tapping, and frame fixing of the front foot ladder is completed. The assembling method has the characteristics of less labor, simplicity in operation, automatic processing, high efficiency and the like, and maximization of production benefits is met.

Description

Technical Field

[0001] The invention relates to the technical field of metal parts processing and assembly, in particular to an automatic feeding, drilling, extrusion and deformation production line for the front legs of a metal folding stepladder. Background Art

[0002] With the development of industry and commerce, people's living space in homes and offices has been reduced. Most daily necessities require simple operation, easy folding and moving to save space. Folding metal stepladders are widely used by the public due to their simple structure and easy storage and portability after folding.

[0003] Combine Figure 1 The metal folding stepladder includes a front ladder A and a rear ladder B movably connected to the front ladder. The front ladder and the rear ladder can usually switch between an unfolded or folded state to meet people's use needs at different times. The front ladder refers to a climbable structure that connects and supports several steps between two ladder tubes. It is the core component of the metal stepladder. The two ladder tubes are arranged in an eight-shaped shape and serve as the supporting parts on both sides of the front ladder. The pedals refer to the horizontal bars on the front ladder for stepping on, which are usually composed of multiple inconsistent horizontal bars with gradually narrowing lengths. The bottom of the front ladder is usually also equipped with anti-slip foot covers for protecting the foot tubes and preventing the ladder from sliding. The upper and middle parts of the front ladder are usually also equipped with a top pedal for users to sit or step on a large area; the top of the front ladder is usually also equipped with a tool box for placing work accessories.

[0004] Due to the unique shape and structure of the front ladder, it often requires processes such as arranging the ladder tubes in an "eight" shape, drilling, punching, extrusion, and other metal surface treatment processes. It also requires the installation of non-slip foot covers at the bottom of both ladder tubes, top treads at the middle and upper parts of both ladder tubes, and tool boxes at the tops of both ladder tubes. In production practice, these processes are usually completed individually by manual labor. Some processes are also automated, but they still require multiple people to operate, such as loading and unloading, manual drilling and punching, extrusion, pre-assembly of accessories such as crossbars and top treads, and installation of accessories such as non-slip foot covers, crossbars, top treads, and tool boxes.

[0005] To further reduce costs and improve processing efficiency, we've designed an automated processing line that allows for pre-installation of accessories, automatic figure-eight loading and placement of ladder tubes, automated drilling and punching, automatic extrusion deformation, and automated assembly of each accessory. This production line features minimal labor, simple operation, automated processing, and high efficiency, ensuring maximum production efficiency.

[0006] Therefore, we propose a method for assembling the front foot ladder of a metal herringbone ladder in order to solve the problems raised above. Summary of the Invention

[0007] In order to overcome the deficiencies of the prior art, the present invention aims to provide a method for assembling the front legs of a metal stepladder.

[0008] The purpose of the present invention is achieved by adopting the following technical solution: a method for assembling the front foot ladder of a metal herringbone ladder, which is assembled using a metal herringbone ladder front foot ladder assembly device, specifically comprising the following steps:

[0009] Loading: The ladder pipe is horizontally transferred to the front of the horizontal drilling station through the ladder pipe loading mechanism, and then the ladder pipe at the end of the conveying end is flipped from the horizontal state to the upright state;

[0010] Horizontal drilling: The first manipulator grabs the upright ladder tube, transfers it horizontally to the ladder tube limit seat, clamps and fixes its position, and drills and / or punches holes on the inside of the ladder tube through the horizontal drilling mechanism;

[0011] Foot cover installation and extrusion positioning: After completing the horizontal drilling, the foot cover is pushed into the ladder tube from one end through the foot cover installation mechanism, and then the extrusion deformation mechanism applies external force to the preset position of the ladder tube, causing the ladder tube to be partially concave and deformed to fix the foot cover at the end of the ladder tube;

[0012] Finalizing the front ladder components: The second robot grabs the two ladder tubes after the foot covers are installed, tilts and turns them, and places them in a figure-eight shape at the preset position of the front ladder limit fixture. The crossbar and top pedal are manually placed between the two ladder tubes according to the preset position of the front ladder limit fixture, completing the frame installation of the front ladder.

[0013] Vertical drilling and tapping: The Y-axis conveying device transfers the entire front foot ladder limit fixture to the vertical drilling and tapping station, and the vertical drilling and tapping device locks the crossbar and top pedal on the ladder tube to complete the overall fixation of the front foot ladder frame.

[0014] Furthermore, in the loading step, the ladder pipe loading mechanism includes an X-axis conveying device for horizontally conveying the ladder pipe, a steering device for horizontally turning the ladder pipe 90°, and a first manipulator mechanism for transferring the ladder pipe A1 from the loading station to the drilling station, and the steering device is arranged at the end of the conveying direction of the X-axis conveying device; when the ladder pipes are placed side by side horizontally on the X-axis conveying device, when the X-axis conveying device conveys the ladder pipe to the steering device, the steering device rotates so that the short side of the ladder pipe cross section faces upward; the second manipulator mechanism transfers the ladder pipe from the loading station to the drilling station.

[0015] Furthermore, in the horizontal drilling step, the horizontal drilling mechanism includes a ladder pipe limit seat, a horizontal drilling and tapping device, a horizontal punching device, and a clamping assembly; the horizontal drilling and tapping device and the horizontal punching device are located on one side of the ladder pipe limit seat, and the clamping assembly is arranged on the other side of the ladder pipe limit seat. When the horizontal drilling mechanism detects that the ladder pipe is placed on the ladder pipe limit seat, the clamping assembly presses the ladder pipe in the ladder pipe limit seat, and the horizontal drilling and tapping device and the horizontal punching device perform drilling and tapping or / and punching at the preset drilling position of the ladder pipe.

[0016] Furthermore, in the step of adding and squeezing the foot cover, the foot cover installation mechanism includes a magazine slot for conveying the foot cover, a reciprocating pusher arranged in the magazine slot, a power device for driving the reciprocating pusher to slide in the magazine slot, and a pushing assembly for pushing the foot cover out of the magazine slot and into the bottom end of the ladder tube; the magazine slot is provided with at least one discharge port and a feed port;

[0017] The extrusion deformation mechanism includes an extrusion block, an extrusion block Z-axis expansion and contraction device that drives the extrusion block to expand and contract up and down along the Z-axis direction, and an extrusion block Y-axis sliding device that drives the extrusion block Z-axis expansion and contraction device to move left and right along the Y-axis direction. The extrusion block is located above the foot cover mounting mechanism.

[0018] The foot sleeve enters the material box slot from the feed inlet and is pushed to the discharge outlet by the reciprocating pusher. When it is detected that the ladder pipe out of the discharge outlet is in place, the push-up assembly extends to push the foot sleeve out of the material box slot and push it into the bottom end of the ladder pipe. When the foot sleeve is installed at the bottom end of the ladder pipe, the extrusion block is moved to a preset position above the ladder pipe by the extrusion block shaft sliding device, and then driven downward by the extrusion block Z-axis telescopic device to extrude it. The ladder pipe is partially concave and deformed at the preset position to fix the foot sleeve at the bottom end of the ladder pipe.

[0019] Furthermore, in the step of finalizing the front foot ladder accessories, the front foot ladder limiting fixture includes a base plate, a first ladder tube limiting seat, a second ladder tube limiting seat, a crossbar limiting seat, a foot sleeve positioning seat, a pedal limiting seat, and a locking piece; the first ladder tube limiting seat and the second ladder tube limiting seat are arranged in an eight-shaped shape on the base plate, and the crossbar limiting seat and the pedal limiting seat are arranged between the first ladder tube limiting seat and the second ladder tube limiting seat; the first ladder tube limiting seat is fixedly mounted on the base plate, and the second ladder tube limiting seat is movably mounted on the base plate at a position close to or away from the first ladder tube limiting seat; foot sleeve positioning seats are provided at the ends of the first ladder tube limiting seat and the second ladder tube limiting seat, for limiting the starting position of the foot sleeve at the bottom of the front foot ladder;

[0020] After the foot cover is installed, the ladder tube is automatically installed on the first ladder tube limit seat and the second ladder tube limit seat by the second manipulator mechanism, and is distributed in an eight-shaped shape. Then, the cross bar, top pedal and other accessories are manually installed between the two ladder tubes. There is a U-shaped opening at each end of the cross bar, which is used to clip into the ladder tubes at both ends. Then the second ladder tube limit seat is slid close to the first ladder tube limit seat, and the position of the second ladder tube limit seat is fixed by a locking piece, so that the front foot ladder is installed completely according to the preset angle and position, and limited on the front foot ladder limit fixture, which is convenient for the subsequent vertical drilling process, that is, the cross bar and the ladder tube are drilled and locked by the existing vertical drilling device, so as to realize the transformation of the cumbersome fastener positioning process into a simple direct drilling process.

[0021] Furthermore, in the vertical drilling and tapping step, the Y-axis transport device transfers the entire front foot ladder limiting fixture to the vertical drilling and tapping station. At this time, the ladder tubes on the front foot ladder limiting fixture are distributed in an eight-shaped shape, and the cross bar and the top pedal are locked on the ladder tube through the vertical drilling and tapping device to complete the overall fixation of the front foot ladder frame.

[0022] Furthermore, after vertical drilling and tapping, the method further includes the step of installing a tool box;

[0023] In the tool box installation step, the tool box is clamped and transferred to the preset tool box limiting jig by the tool box installation mechanism, and the left and right push handle mechanisms on the tool box limiting jig clamp and fix the tool box. The tool box limiting jig is pushed to the side of the front foot ladder limiting jig that has completed the vertical drilling and tapping process, and the tool box is inserted into the top of the two ladder pipes arranged in an eight-shaped shape. The tool box is fixed to the top of the ladder pipe by the fasteners on the drilling and tapping device to complete the installation of the tool box.

[0024] Furthermore, the tool box installation mechanism includes a tool box loading device for conveying the tool box, a third manipulator for grabbing the tool box, a tool box limiting fixture for fixing the position of the tool box, a tool box clamping hand for clamping the tool box on the tool box limiting fixture, a tool box pushing device for pushing the tool box to the top of the two ladder pipes, and a tool box drilling and tapping device for locking the tool box on the two ladder pipes; if the direction of the tool box needs to be adjusted, the tool box installation mechanism also includes a rotating tool for adjusting the direction of the tool box;

[0025] The third robot is driven by a power drive to move along the X-axis and Z-axis directions, so that it transfers the loading device or the rotary tooling to the tool box limiting fixture, and the tool box clamp is fixed to the tool box limiting fixture; the tool box pushing device is driven by a power drive to move along the Y-axis and Z-axis directions. At this time, after adjusting the height direction of the Z-axis by the tool box pushing device, the tool box is transported along the Y-axis direction until it is inserted into the top of the two ladder tubes. The tool box drilling and tapping device is located on the top of the ladder tube and the tool box. The tool box drilling and tapping device rotates downward along the Z-axis direction, and the tool box is locked on the two ladder tubes by fasteners to complete the installation of the tool box.

[0026] Furthermore, the method further includes a crossbar pre-installation step before loading: in the crossbar pre-installation step, concave connectors for quick installation are provided at both ends of the crossbar, and the concave connectors are fixed to both ends of the crossbar by a crossbar pre-installation mechanism;

[0027] The crossbar pre-installation mechanism includes a crossbar limiting fixture for fixing the crossbar, a crossbar pressing device for pressing the crossbar, a connector feeding device for conveying the concave connector, a connector limiting seat for limiting the position of the concave connector, an anti-dislocation device for preventing the concave connector from slipping, and a connector pushing device for pushing and fixing the concave connector at both ends of the crossbar;

[0028] First, press and fix the cross bar on the cross bar limiting fixture. The connector feeding device delivers the concave connector to the connector limiting seat through the feeding trough. Then the connector pushing device pushes the concave connector and fixes it on both ends of the cross bar to complete the pre-installation process of the cross bar.

[0029] Furthermore, before loading, the method further includes a step of pre-installing the top tread through a pipe: in the step of pre-installing the top tread through a pipe, the top tread is provided with a pivot tube for pivotally connecting between the two ladder tubes, the pivot tube is inserted into the top tread by a top tread through a pipe-piercing mechanism, and is rotatably fixed on the top tread;

[0030] The top pedal pipe-threading and dotting mechanism includes a pedal limiting jig, a material guide trough, a rotating frame, a guide device, and a downward pressure limiting device; the top pedal is placed and limited on the pedal limiting jig, and the top pedal is provided with a mounting hole for installing the pivot tube; the material guide trough is provided with a discharge port for a pivot tube to pass through and a material guide slope for providing gravity power to the discharge port; the rotating frame is arranged on one side of the discharge port, and is used to rotate and transport the pivot tube of the discharge port to a preset height of the mounting hole; the guide device inserts the pivot tube on the rotating frame into the mounting hole of the top pedal from the horizontal direction, and reserves pipe ports of the same length on both sides of the top pedal; the downward pressure device presses down on the pipe ports on both sides of the top pedal in the vertical direction to deform the pipe ports, thereby limiting the range of movement of the top pedal in the pivot tube.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] To further reduce costs and improve processing efficiency, we've designed an automated processing equipment that enables pre-installation of accessories, automatic figure-eight loading and placement of ladder tubes, automated drilling and punching, automatic extrusion deformation, and automated assembly lines for each accessory. This production line features minimal labor, simple operation, automated processing, and high efficiency, ensuring maximum production benefits.

[0033] 2. Specifically, the present invention arranges two ladder tubes in an eight-shaped shape on the front foot ladder limiting fixture, and simultaneously pre-installs other accessories such as cross bars and foot covers on the front foot ladder limiting fixture. The front foot ladder limiting fixture pre-sets the various limiting seats of the accessories required for the front foot ladder A, which facilitates the implementation of subsequent drilling and fixing processes. Through the operation of various mechanisms on the production line of the present invention, the above-mentioned accessories complete the position pre-installation, pre-drilling, and extrusion deformation to realize the automated installation of scattered accessories, thereby improving production efficiency.

[0034] 3. In the present application, the ladder pipes are transported horizontally and side by side to the notch in the rotating disc at the loading station through a belt device, and then the steering device is rotated, and the horizontally lying ladder pipes are turned to a certain angle to flip them to an upright state. On the one hand, it is convenient for the second manipulator mechanism to clamp them, and on the other hand, the direction of the ladder pipes is flipped in advance to facilitate direct construction at the drilling station.

[0035] 4. According to the installation requirements of the crossbar and the top pedal, fastening holes or installation holes are opened in advance on the ladder tube. Specifically, several horizontal drilling and tapping devices and / or horizontal punching devices are set in the middle of the mounting platform. In order to improve the adaptability of assembling different products of herringbone ladders, the horizontal drilling and tapping devices and / or horizontal punching devices of the present invention can be provided with multiple axial moving devices such as X-axis, Y-axis, and Z-axis (not marked in the drawings), which are used to drive the horizontal drilling and tapping devices and / or horizontal punching devices to move to the required position for drilling, thereby improving the processing adaptability and efficiency of this work station.

[0036] 5. Existing foot covers usually require manual installation, repeated adjustment of the installation position, and additional manual extrusion and shaping processes after installation. The assembly efficiency is extremely low, and the ladder pipe fittings are long, which makes installation and transportation inconvenient and requires a larger processing site, which is not conducive to mass production of the product. To this end, the present invention inserts the process of automatic assembly of the foot cover during the drilling process, and can complete the assembly of the entire foot cover before transferring to the eight-shaped front foot ladder assembly station. Specifically, it includes two steps: the insertion of the foot cover and the extrusion deformation of the ladder pipe. The above processing steps are completely completed by automatic processing of the equipment, without the need for manual intervention, which greatly improves production efficiency and avoids tolerance errors in manual assembly. In addition, this mechanism is located on the upper side of the mounting platform, rationally utilizing the positions on both sides of the drilling station, improving the utilization efficiency of the site, and improving the overall production and assembly efficiency.

[0037] 6. In order to further improve efficiency and rationally utilize the processing space in the factory, the present invention specifically improves the feeding efficiency of the foot cover by designing the material inlet and outlet positions in the material box slot and coordinating with the reciprocating push handle structure. At the same time, combined with the cooperation of the ladder tube turning device, it can shorten the overall installation time of the foot cover of a single stepladder, greatly free up manpower and improve assembly efficiency.

[0038] 7. The present invention provides an angle adjustment device in the manipulator mechanism. After the clamping device grips the ladder tube, it rotates it outward or inward to a preset angle. The angle adjustment is achieved and completed by setting the cylinder stroke and the pivotal relationship between the two mounting plates. The structure is simple and can realize two-way adjustment, thereby realizing the automated assembly of the figure-eight ladder legs.

[0039] 8. The present invention designs a Y-axis transport device, and the eight-shaped front foot ladder shaping station and the vertical drilling and tapping station share the same Y-axis transport device. The Y-axis transport device has two layers of conveyor belts, which carry out a circular transport of the front foot ladder limiting fixture between the two layers of conveyor belts, thereby realizing the circular installation of the eight-shaped front foot ladder, improving the transport efficiency of the limiting fixture, and improving production efficiency.

[0040] 9. This application designs a tool box installation mechanism to clamp and transfer the tool box to a preset tool box limiting jig. The left and right push handle mechanisms on the tool box limiting jig clamp and fix the tool box. The tool box limiting jig is pushed to the side of the front ladder limiting jig that has completed the vertical drilling and tapping process, and the tool box is inserted into the top of two ladder pipes arranged in an eight-shaped shape. The tool box is fixed to the top of the ladder pipe through the fasteners on the drilling and tapping device to complete the installation of the tool box.

[0041] 10. The present invention completes the pre-installation of the crossbar, the connecting parts and the pivot on the top pedal by designing a crossbar pre-installation mechanism and a top pedal pipe threading and dotting mechanism. This is solved through equipment automation, which releases manpower and improves production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is a structural diagram of a metal folding herringbone ladder in the prior art;

[0043] Figure 2 This is a schematic structural diagram of the front ladder in the metal folding herringbone ladder of the present invention;

[0044] Figure 3 This is a structural diagram of a metal step ladder front foot ladder assembly device according to a preferred embodiment of the present invention;

[0045] Figure 4 This is a structural diagram of the ladder tube feeding mechanism, horizontal drilling mechanism, foot cover installation mechanism, extrusion deformation mechanism, and second manipulator mechanism of a preferred embodiment of the present invention;

[0046] Figure 5 This is a structural diagram of a ladder pipe feeding mechanism according to a preferred embodiment of the present invention;

[0047] Figure 6 for Figure 5 A magnified schematic diagram of point a in the middle;

[0048] Figure 7 This is a structural diagram of the horizontal drilling mechanism, the foot cover installation mechanism, the extrusion deformation mechanism, and the second manipulator mechanism of a preferred embodiment of the present invention;

[0049] Figure 8 An enlarged schematic diagram of the first manipulator mechanism of a preferred embodiment of the present invention;

[0050] Figure 9 for Figure 8 The enlarged schematic diagram of point b in the middle;

[0051] Figure 10 This is an enlarged schematic diagram of the second manipulator mechanism of a preferred embodiment of the present invention;

[0052] Figure 11 This is a structural diagram of the drilling mechanism and the foot cover installation mechanism of a preferred embodiment of the present invention;

[0053] Figure 12 for Figure 11 The enlarged schematic diagram of point c in the middle;

[0054] Figure 13 for Figure 12 A partial enlarged schematic diagram;

[0055] Figure 14 for Figure 13 The enlarged schematic diagram of point d in the middle;

[0056] Figure 15 This is a structural diagram of the drilling mechanism and the foot cover installation mechanism from another angle in a preferred embodiment of the present invention;

[0057] Figure 16 for Figure 15 A partial enlarged schematic diagram;

[0058] Figure 17 This is a structural diagram of a front ladder limiting fixture according to a preferred embodiment of the present invention;

[0059] Figure 18 This is a schematic structural diagram of a vertical drilling and tapping device according to a preferred embodiment of the present invention;

[0060] Figure 19 This is a schematic structural diagram of a tool box installation mechanism according to a preferred embodiment of the present invention;

[0061] Figure 20 This is a structural diagram of a tool box installation mechanism lacking a drilling and tapping device according to a preferred embodiment of the present invention;

[0062] Figure 21 for Figure 20 The enlarged schematic diagram of point e in the middle;

[0063] Figure 22 This is a structural diagram of a tool box drilling and tapping device and a tool box clamp according to a preferred embodiment of the present invention;

[0064] Figure 23 This is a schematic structural diagram of a crossbar in a preferred embodiment of the present invention;

[0065] Figure 24 This is a structural diagram of a crossbar pre-assembly mechanism according to a preferred embodiment of the present invention;

[0066] Figure 25 for Figure 24 The enlarged schematic diagram at point f in the middle;

[0067] Figure 26 This is a structural diagram of the top pedal pipe-piercing and dotting mechanism of a preferred embodiment of the present invention;

[0068] Figure 27 This is a structural diagram of the top pedal pipe-piercing and dotting mechanism from another angle according to a preferred embodiment of the present invention;

[0069] In the figure: 1, ladder tube loading mechanism; 11, X-axis conveying device; 12, steering device; 121, rotating disc; 122, notch; 13, first manipulator mechanism; 131, first gripper device; 132, first gripper Z-axis lifting device; 133, first gripper Y-axis moving device;

[0070] 2. Horizontal drilling mechanism; 21. Ladder pipe limit seat; 22. Horizontal drilling device; 23. Horizontal punching device; 24. Pressing assembly; 241. Pressing block; 242. Spinning device;

[0071] 3. Foot cover mounting mechanism; 31. Material box slot; 311. Material outlet; 312. Material inlet; 32. Reciprocating pusher; 33. Power unit; 34. Pushing assembly; 35. Ladder tube turning device; 351. Rotating arm; 352. Movable gripper; 353. Rotating arm Z-axis lifting device;

[0072] 4. Extrusion deformation mechanism; 41. Extrusion block; 42. Extrusion block Z-axis telescopic device; 43. Extrusion block Y-axis sliding device;

[0073] 5. Second manipulator mechanism; 51. Second gripper device; 52. Second gripper Z-axis lifting device; 53. Second gripper Y-axis moving device; 54. Angle adjustment device; 541. First mounting plate; 542. Second mounting plate; 543. Adjustment cylinder; 544. Pivot; 55. Position sensor;

[0074] 6. Front ladder limit fixture; 61. Bottom plate; 62. First ladder tube limit seat; 63. Second ladder tube limit seat; 64. Crossbar limit seat; 65. Foot cover positioning seat; 66. Pedal limit seat; 67. Locking fastener;

[0075] 7. Vertical drilling and tapping device; 71. Side clamping assembly; 72. Vertical drilling and tapping assembly; 73. Guide seat;

[0076] 8. Tool box installation mechanism; 81. Tool box loading device; 82. Third manipulator; 83. Tool box limiting fixture; 84. Tool box gripper; 85. Tool box pushing device; 86. Tool box drilling and tapping device; 87. Rotary tooling;

[0077] 9. Crossbar pre-assembly mechanism; 91. Crossbar limiting fixture; 92. Crossbar pressing device; 93. Connector feeding device; 94. Connector limiting seat; 95. Anti-dislocation device; 96. Connector pushing device;

[0078] 10. Top pedal tube-threading and dotting mechanism; 101. Pedal limit fixture; 102. Material guide trough; 103. Rotating frame; 104. Pipe-threading device; 105. Downward pressure limit device;

[0079] 111. Y-axis transport device;

[0080] A. Front ladder; A1. Ladder tube; A2. Crossbar; A21. Concave connector; A3. Foot covers; A4. Top step; A5. Tool box; B. Rear ladder. DETAILED DESCRIPTION

[0081] The present invention will be further described below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0082] like Figure 1 As shown, the metal folding ladder referred to in this technology includes a front ladder A and a rear ladder B movably connected to the front ladder A. The front ladder A and the rear ladder B are usually switched between the unfolded and folded states to meet people's usage needs at different times. Figure 2 As shown, the front ladder A of the present invention is a climbable structure consisting of several steps connected and supported between two ladder tubes. It is the core component of a metal stepladder. The two ladder tubes A1 are arranged in a figure-eight pattern and serve as the supporting elements on either side of the front ladder. The steps are horizontal bars A2 on the front ladder A for stepping on, typically consisting of multiple, non-uniform bars of gradually tapering lengths. The bottom of the front ladder A is typically equipped with foot covers A3 to protect the foot tubes and prevent the ladder from sliding. A top step A4 is typically installed on the top of the front ladder A. A tool box A5 is also typically installed at the top of the front ladder A for storing work accessories.

[0083] The method for assembling the front ladder of a metal step ladder of the present invention is the core processing step of the front ladder A of the metal step ladder. The main accessories and structures of the front ladder A are pre-assembled through the production line of the present invention, which facilitates the subsequent assembly of the rear ladder and avoids the problem of excessive tolerance or low efficiency caused by manual assembly of all accessories.

[0084] like Figure 3-27 As shown, a method for assembling the front foot ladder of a metal herringbone ladder is provided, wherein the assembly is performed using a metal herringbone ladder front foot ladder assembly device, wherein the metal herringbone ladder front foot ladder assembly device is provided with a crossbar pre-assembly station, a pedal tube threading and dotting pre-assembly station, a ladder tube loading station, a horizontal drilling station, a foot cover installation station, an S-shaped front foot ladder shaping station, a vertical drilling and tapping station, and a tool box installation station;

[0085] Among them, the figure-eight front foot ladder shaping station and the vertical drilling and tapping station share a Y-axis transport device. The Y-axis transport device has two layers of conveyor belts, which carry out a circular transfer of the front foot ladder limiting fixture between the two layers of conveyor belts, thereby realizing the circular installation of the figure-eight front foot ladder, improving the transfer efficiency of the limiting fixture, and improving production efficiency.

[0086] The assembly method of the front foot ladder of the metal step ladder includes the following steps:

[0087] Loading: The ladder pipe A1 is horizontally transferred to the front of the horizontal drilling station through the ladder pipe loading mechanism 1, and then the ladder pipe A1 at the end of the conveying is flipped from the horizontal state to the upright state;

[0088] Horizontal drilling: The first manipulator grips the upright ladder tube A1, transfers it horizontally to the ladder tube limit seat, clamps it in place, and drills and / or punches holes on the inside of the ladder tube A1 using the horizontal drilling mechanism.

[0089] Foot cover installation and extrusion positioning: After completing the horizontal drilling, the foot cover A3 is pushed into the ladder tube from one end through the foot cover installation mechanism, and then the extrusion deformation mechanism applies external force to the preset position of the ladder tube, causing the ladder tube A1 to be partially concave and deformed, thereby fixing the foot cover at the end of the ladder tube A1;

[0090] Finalizing the front ladder components: The second robot grabs the two ladder tubes A1 after the foot covers are installed, tilts them, and places them in a figure-eight shape on the preset position of the front ladder limit fixture. The crossbar A2 and top pedal A4 are manually placed between the two ladder tubes A1 according to the preset position of the front ladder limit fixture, completing the frame installation of the front ladder A.

[0091] Vertical drilling and tapping: The conveying device transfers the entire front foot ladder limit fixture to the vertical drilling and tapping station, and the crossbar A2 and the top pedal A4 are locked on the ladder tube A1 through the vertical drilling and tapping device to complete the overall fixation of the front foot ladder A frame.

[0092] The horizontal drilling station, the foot cover installation station, and the figure-eight front foot ladder shaping station share a set of second manipulator mechanisms for grabbing, transferring, and steering the ladder pipe A1 between the stations according to the needs of the stations.

[0093] The present invention arranges two ladder tubes A1 in an eight-shape on the front foot ladder limiting fixture 6, and other accessories such as cross bars A2, foot covers A3, top pedals A4, tool boxes A5 are also pre-installed on the front foot ladder limiting fixture 6. The front foot ladder limiting fixture 6 pre-sets the various limiting seats of the accessories required for the front foot ladder A, which facilitates the implementation of subsequent drilling and fixing processes. Through the operation of various mechanisms on the production line of the present invention, the above-mentioned accessories complete the position pre-installation, pre-drilling, and extrusion deformation to realize the automatic installation of scattered accessories, thereby improving production efficiency.

[0094] As a further preferred embodiment, in the loading step, the ladder pipe loading mechanism 1 includes an X-axis conveying device 11 for horizontally conveying the ladder pipe A1, a steering device 12 for horizontally turning the ladder pipe A1 90 degrees, and a first manipulator mechanism 13 for transferring the ladder pipe A1 from the loading station to the drilling station, wherein the steering device 12 is arranged at the end of the conveying direction of the X-axis conveying device 11; when the ladder pipes A1 are placed side by side horizontally on the X-axis conveying device 11, when the X-axis conveying device 11 conveys the ladder pipe A1 to the steering device 12, the steering device 12 rotates so that the short side of the cross section of the ladder pipe A1 faces upward; the first manipulator mechanism 13 transfers the ladder pipe A1 from the loading station to the drilling station;

[0095] The steering device 12 is provided with a rotating disc 121, and a plurality of notches 122 are provided on the periphery of the rotating disc 121 for accommodating the ladder pipe A1. When the ladder pipe is pushed into the notch 122 by the X-axis conveying device 11, the rotating disc 121 is driven to rotate by a power device, thereby flipping the ladder pipe A1 from a horizontal state to an upright state; wherein the power device includes but is not limited to existing transmission devices such as a motor and a belt transmission device.

[0096] The first manipulator mechanism 13 includes a first gripper device 131, a first gripper Z-axis lifting device 132 for driving the gripper device to move along the Z-axis direction, and a first gripper Y-axis moving device 133 for driving the gripper Z-axis lifting device to move left and right along the Y-axis direction.

[0097] In the present application, the ladder pipe A1 is transported horizontally and side by side to the notch 122 in the rotating disc 121 at the loading station through a belt device, and then the steering device 12 is rotated, and the horizontally lying ladder pipe A1 is turned to a certain angle to flip it to an upright state. On the one hand, it is convenient for the first manipulator mechanism 13 to clamp it, and on the other hand, the direction of the ladder pipe A1 is flipped in advance to facilitate direct construction at the drilling station.

[0098] As a further preferred embodiment, in the horizontal drilling step, the horizontal drilling mechanism 2 includes a ladder pipe limit seat 21, a horizontal drilling and tapping device 22, a horizontal punching device 23, and a clamping assembly 24; the horizontal drilling and tapping device 22 and the horizontal punching device 23 are located on one side of the ladder pipe limit seat 21, and the clamping assembly 24 is arranged on the other side of the ladder pipe limit seat 21. When the horizontal drilling mechanism 2 detects that the ladder pipe A1 is placed on the ladder pipe limit seat 21, the clamping assembly 24 presses the ladder pipe A1 into the ladder pipe limit seat 21, and the horizontal drilling and tapping device 22 and the horizontal punching device 23 perform drilling and tapping or / and punching at the preset drilling position of the ladder pipe A1;

[0099] The pressing assembly 24 includes a pressing block 241 and a spinning device 242 that is transmission-connected to the pressing block 241 . The spinning device 242 drives the pressing block 241 to switch between a state of pressing the ladder pipe and a state of loosening and moving away from the ladder pipe.

[0100] According to the installation requirements of the crossbar A2 and the top pedal A4, fastening holes or installation holes are pre-opened on the ladder pipe A1. Specifically, a number of horizontal drilling and tapping devices 22 and / or horizontal punching devices 23 are set in the middle of the mounting platform. In order to improve the adaptability of assembling different products of herringbone ladders, the horizontal drilling and tapping devices 22 and / or horizontal punching devices 23 of the present invention can be provided with multiple axial moving devices such as X-axis, Y-axis, and Z-axis (not marked in the drawings), which are used to drive the horizontal drilling and tapping devices 22 and / or horizontal punching devices 23 to move to the required position for drilling, thereby improving the processing adaptability and efficiency of this work station.

[0101] As a further preferred embodiment, in the step of adding and squeezing the foot cover, the foot cover installation mechanism 3 includes a material box slot 31 for conveying the foot cover A3, a reciprocating pusher 32 arranged in the material box slot 31, a power device 33 for driving the reciprocating pusher 32 to slide in the material box slot 31, and a pushing assembly 34 for pushing the foot cover A3 out of the material box slot 31 and pushing it into the bottom end of the ladder pipe A1; the material box slot 31 is provided with at least one discharge port 311 and a feed port 312; the foot cover A3 enters the material box slot 31 from the feed port 312 and is pushed to the discharge port 311 by the reciprocating pusher 32. When it is detected that the discharge port 311 is in place out of the ladder pipe A1, the pushing assembly 34 extends to push the foot cover A3 out of the material box slot 31 and push it into the bottom end of the ladder pipe A1.

[0102] The extrusion deformation mechanism 4 includes an extrusion block 41, an extrusion block Z-axis telescopic device 42 that drives the extrusion block 41 to extend and retract up and down along the Z-axis direction, and an extrusion block Y-axis sliding device 43 that drives the extrusion block Z-axis telescopic device 42 to move left and right along the Y-axis direction. The extrusion block 41 is located above the foot cover mounting mechanism 3; when the foot cover A3 is installed at the bottom end of the ladder pipe A1, the extrusion block 41 is moved to a preset position above the ladder pipe A1 by the extrusion block Y-axis sliding device 43, and then driven downward by the extrusion block Z-axis telescopic device 42 to be extruded, and the ladder pipe A1 is locally concave and deformed at the preset position to fix the foot cover at the bottom end of the ladder pipe A1.

[0103] The existing foot cover A3 usually requires manual installation, repeated adjustment of the installation position, and an additional manual extrusion and shaping process after installation. The assembly efficiency is extremely low, and the ladder pipe A1 pipe fittings are long, which makes installation and transportation inconvenient and requires a larger processing site, which is not conducive to mass production of the product. To this end, the present invention inserts the process of automated assembly of the foot cover A3 during the drilling process, and can complete the assembly of the entire foot cover A3 before transferring to the figure-eight front foot ladder assembly station. Specifically, it includes two steps: the insertion of the foot cover A3 and the extrusion deformation of the ladder pipe A1. The above processing steps are completely completed by automated processing of the equipment, without the need for manual intervention, which greatly improves production efficiency and avoids tolerance errors in manual assembly. In addition, this mechanism is located on the upper side of the mounting platform, rationally utilizing the positions on both sides of the drilling station, improving the utilization efficiency of the site, and improving the overall production and assembly efficiency.

[0104] In this embodiment, the foot cover installation mechanism 3 also includes a ladder tube flipping device 35, which is arranged between the two ladder tube limit seats 21, and is used to take out the ladder tube A1 that has completed the drilling process and is located in the ladder tube limit seat 21, and flip it to another ladder tube limit seat 21 to wait for the foot cover installation process; specifically, the ladder tube flipping device 35 includes a rotating arm 351, a movable gripper 352 installed at the end of the rotating arm 351, and a rotating arm Z-axis lifting device 353 that drives the rotating arm 351 to move up and down along the Z-axis direction.

[0105] In order to further improve efficiency and rationally utilize the processing space in the factory, the present invention specifically improves the feeding efficiency of the foot cover A3 by designing the material input and output positions in the material box slot 31 and coordinating with the reciprocating push handle 32 structure. At the same time, combined with the cooperation of the ladder tube turning device 35, it can shorten the installation time of the foot cover of a single stepladder as a whole, greatly freeing up manpower and improving assembly efficiency.

[0106] As a further preferred solution, in the step of finalizing the front foot ladder accessories, the front foot ladder limiting fixture 6 includes a base plate 61, a first ladder tube limiting seat 62, a second ladder tube limiting seat 63, a crossbar limiting seat 64, a foot cover positioning seat 65, a pedal limiting seat 66, and a locking member 67;

[0107] The first ladder tube limiting seat 62 and the second ladder tube limiting seat 63 are arranged in an eight-shaped shape on the base plate 61, and the cross bar limiting seat 64 and the pedal limiting seat 66 are arranged between the first ladder tube limiting seat 62 and the second ladder tube limiting seat 63; the first ladder tube limiting seat 62 is fixedly installed on the base plate 61, and the second ladder tube limiting seat 63 is movably installed on the base plate 61 at a position close to or far away from the first ladder tube limiting seat 62; the ends of the first ladder tube limiting seat 62 and the second ladder tube limiting seat 63 are provided with foot sleeve positioning seats 65, which are used to limit the starting position of the foot sleeve A3 at the bottom of the front foot ladder.

[0108] After the foot cover A3 is installed, the ladder tube A1 is automatically installed on the first ladder tube limit seat 62 and the second ladder tube limit seat 63 by the second manipulator mechanism 5, and is distributed in an eight-shaped shape. Then, the cross bar A2, the top pedal A4 and other accessories are manually installed between the two ladder tubes A1. The two ends of the cross bar A2 have a U-shaped opening for clamping into the ladder tubes A1 at both ends. Then, the second ladder tube limit seat 63 is slid close to the first ladder tube limit seat 62, and the position of the second ladder tube limit seat 63 is fixed by a locking member, so that the front foot ladder A is installed completely according to the preset angle and position, and limited on the front foot ladder limit fixture 6, which is convenient for the subsequent vertical drilling process, that is, the cross bar A2 and the ladder tube A1 are drilled and locked by the existing vertical drilling device 7, so as to realize the transformation of the cumbersome fastener positioning process into a simple direct drilling process.

[0109] In this embodiment, specifically, the second manipulator mechanism 5 includes a second gripper device 51, a second gripper Z-axis lifting device 52 for driving the second gripper device 51 to move along the Z-axis direction, a second gripper Y-axis moving device 53 for driving the second gripper Z-axis lifting device 52 to move left and right along the Y-axis direction, and an angle adjustment device 54 for adjusting the gripper device to a preset angle;

[0110] The angle adjustment device 54 includes a first mounting plate 541, a second mounting plate 542, and an adjusting cylinder 543; the first mounting plate 541 is movably pivoted to the second mounting plate 542 through a pivot 544, and the end of the first mounting plate 541 away from the pivot 544 is fixed to the clamping device, and the end of the second mounting plate 542 away from the pivot 544 is fixed to the clamping Z-axis lifting device; the adjusting cylinder 543 is arranged on the side away from the pivot 544, one end of the adjusting cylinder 543 is pivoted to the clamping device, and the other end of the adjusting cylinder 543 is pivoted to the clamping Z-axis lifting device.

[0111] The present invention provides an angle adjustment device 54 in the manipulator mechanism. After the gripping device grips the ladder tube A1, it rotates it outward or inward to a preset angle. The angle adjustment is achieved and completed by setting the cylinder stroke and the pivotal relationship between the two mounting plates. The structure is simple and can realize two-way adjustment, thereby realizing the automated assembly of the figure-eight ladder legs.

[0112] In a preferred embodiment of this invention, in order to achieve high-precision automated control of the second manipulator mechanism 5, the gripper Z-axis lifting device is provided with a plurality of vertically arranged position sensors 55. The vertically arranged position sensors 55 can provide height position control, achieving high-precision alignment, gripping, and transfer operations.

[0113] As a further preferred solution, in the vertical drilling step, the Y-axis transport device 111 transfers the entire front foot ladder limiting jig 6 to the vertical drilling station. At this time, the ladder tube A1 on the front foot ladder limiting jig 6 is distributed in an eight-shaped shape, and the cross bar A2 and the top pedal A4 are locked on the ladder tube A1 through the vertical drilling device 7 to complete the overall fixation of the frame of the front foot ladder A.

[0114] Specifically, two vertical drilling and tapping devices 7 form a group, and at least one group of vertical drilling and tapping devices 7 is provided on the Y-axis transport device 111. In order to improve the vertical drilling and tapping efficiency of this production line, this preferred solution provides three groups of vertical drilling and tapping devices 7, each group of vertical drilling and tapping devices 7 is respectively arranged on both sides of a front foot ladder limit fixture 6, and each vertical drilling and tapping device 7 includes a top clamping component (not shown in the figure), a side clamping component 71, at least one vertical drilling and tapping component 72 and a guide seat 73; the vertical drilling and tapping components 72 can be vertically drilled and tapped symmetrically distributed in an upper and lower manner. The tapping device 7, the top clamping assembly is driven by the power drive part 1 to move along the Z axis direction, the side clamping assembly 71 is driven by the power drive part 2 to move along the X axis and Z axis directions, and the vertical drilling and tapping device 7 is driven by the power drive part 3 to move along the Y axis and Z axis directions; in order to match the angle of the ladder tube A1 distributed in an eight-shaped manner on the front foot ladder limit fixture 6, the guide seat 73 is designed to be distributed in an eight-shaped manner, and the vertical drilling and tapping assemblies 72 are respectively installed on the guide seat 73, which greatly improves the efficiency of the vertical drilling and tapping process without the need for steering adjustment.

[0115] As a further preferred embodiment, after vertical drilling and tapping, a tool box installation step is also included. Specifically, in the tool box installation step, the tool box A5 is clamped and transferred to the preset tool box limiting jig 83 by the tool box installation mechanism 8. The left and right push handle mechanisms on the tool box limiting jig 83 clamp and fix the tool box A5. The tool box limiting jig 83 is pushed to the side of the front ladder limiting jig 6 that has completed the vertical drilling and tapping process, and the tool box A5 is inserted into the top of the two ladder pipes A1 arranged in an eight-shaped shape. The tool box A5 is fixed to the top of the ladder pipe A1 by the fasteners on the drilling and tapping device to complete the installation of the tool box A5.

[0116] In this preferred embodiment, the tool box installation mechanism 8 includes a tool box loading device 81 for conveying the tool box A5, a third manipulator 82 for grasping the tool box A5, a tool box positioning fixture 83 for fixing the tool box A5, a tool box gripper 84 for clamping the tool box A5 to the tool box positioning fixture 83, a tool box pushing device 85 for pushing the tool box A5 to the top of the two ladder tubes A1, and a tool box drilling and tapping device 86 for locking the tool box A5 to the two ladder tubes A1. If the orientation of the tool box A5 needs to be adjusted, the tool box installation mechanism 8 also includes a rotating fixture 87 for adjusting the orientation of the tool box A5. The third manipulator 82 is driven by the power drive part 4 to move along the X-axis and Z-axis directions, so that it transfers the loading device or the rotating tooling 87 to the tool box limiting fixture 83, and the tool box clamp 84 fixes it on the tool box limiting fixture 83; the tool box pushing device 85 is driven by the power drive part 5 to move along the Y-axis and Z-axis directions. At this time, after adjusting the height direction of the Z-axis by the tool box pushing device 85, the tool box A5 is transported along the Y-axis direction until it is inserted into the top of the two ladder pipes A1. In order to further fix the position of the tool box A5, the tool box drilling and tapping device 86 is located at the top of the ladder pipe A1 and the tool box A5. The tool box drilling and tapping device 86 rotates downward along the Z-axis direction, and locks the tool box A5 on the two ladder pipes A1 through fasteners to complete the installation of the tool box A5.

[0117] As a further preferred embodiment, a cross bar pre-installation step is also included before loading: in the cross bar pre-installation step, concave connectors A21 for quick installation are provided at both ends of the cross bar A2, and the concave connectors are fixed to both ends of the cross bar A2 through a cross bar pre-installation mechanism 9.

[0118] The crossbar pre-assembly mechanism 9 includes a crossbar limiting fixture 91 for fixing the crossbar A2, a crossbar pressing device 92 for pressing the crossbar A2, a connector feeding device 93 for conveying the concave connector A21, a connector limiting seat 94 for defining the position of the concave connector A21, an anti-dislocation device 95 for preventing the concave connector A21 from slipping, and a connector pushing device 96 for pushing and fixing the concave connector A21 to both ends of the crossbar. First, the crossbar A2 is pressed and fixed on the crossbar limiting fixture 91. The connector feeding device 93 conveys the concave connector A21 to the connector limiting seat 94 through the feeding trough. Then, the connector pushing device 96 pushes and fixes the concave connector A21 to both ends of the crossbar A2, completing the pre-assembly process of the crossbar A2.

[0119] As a further preferred embodiment, the step of pre-installing the top pedal through pipes and marking is included before loading: in the step of pre-installing the top pedal through pipes and marking, the top pedal A4 is provided with a pivot tube for pivotally connecting between the two ladder tubes A1, and the pivot tube is inserted into the top pedal A4 through the top pedal through pipe marking mechanism 10, and is rotatably limited and installed on the top pedal A4.

[0120] The top pedal pipe-piercing and dotting mechanism 10 includes a pedal limiting jig 101, a material guide trough 102, a rotating frame 103, a penetration device 104, and a downward pressure limiting device 105; the top pedal A4 is placed and limited on the pedal limiting jig 101, and the top pedal A4 is provided with a mounting hole for installing the pivot tube; the material guide trough 102 is provided with a discharge port for a pivot tube to pass through and a material guide slope for providing gravity power to the discharge port; the rotating frame 103 is arranged on one side of the discharge port, and is used to rotate and transport the pivot tube of the discharge port to a preset height of the mounting hole; the penetration device 104 penetrates the pivot tube on the rotating frame 103 into the mounting hole of the top pedal A4 from the horizontal direction, and reserves pipe openings of the same length on both sides of the top pedal A4; the downward pressure device presses down on the pipe openings on both sides of the top pedal A4 in the vertical direction to deform the pipe openings, thereby limiting the range of motion of the top pedal A4 in the pivot tube.

[0121] The above embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and replacements made by technicians in this field on the basis of the present invention fall within the scope of protection required by the present invention.

Claims

1. A method for assembling the front foot of a metal step ladder, characterized in that: The assembly is performed using a metal ladder front foot ladder assembly device, which specifically includes the following steps: Loading: The ladder pipe is horizontally transferred to the front of the horizontal drilling station through the ladder pipe loading mechanism, and then the ladder pipe at the end of the conveying end is flipped from the horizontal state to the upright state; Horizontal drilling: The first manipulator grabs the upright ladder tube, transfers it horizontally to the ladder tube limit seat, clamps and fixes its position, and drills and / or punches holes on the inside of the ladder tube through the horizontal drilling mechanism; Foot cover installation and extrusion positioning: After completing the horizontal drilling, the foot cover is pushed into the ladder tube from one end through the foot cover installation mechanism, and then the extrusion deformation mechanism applies external force to the preset position of the ladder tube, causing the ladder tube to be partially concave and deformed to fix the foot cover at the end of the ladder tube; Finalizing the front ladder components: The second robot grabs the two ladder tubes after the foot covers are installed, tilts and turns them, and places them in a figure-eight shape at the preset position of the front ladder limit fixture. The crossbar and top pedal are manually placed between the two ladder tubes according to the preset position of the front ladder limit fixture, completing the frame installation of the front ladder. Vertical drilling and tapping: The Y-axis conveying device transfers the entire front foot ladder limit fixture to the vertical drilling and tapping station, and the vertical drilling and tapping device locks the crossbar and top pedal on the ladder tube to complete the overall fixation of the front foot ladder frame.

2. The method for assembling the front foot of a metal stepladder according to claim 1, characterized in that: In the loading step, the ladder pipe loading mechanism includes an X-axis conveying device for horizontally conveying the ladder pipe, a steering device for horizontally turning the ladder pipe 90°, and a first manipulator mechanism for transferring the ladder pipe A1 from the loading station to the drilling station, and the steering device is arranged at the end of the conveying direction of the X-axis conveying device; when the ladder pipes are placed side by side horizontally on the X-axis conveying device, when the X-axis conveying device conveys the ladder pipe to the steering device, the steering device rotates so that the short side of the ladder pipe cross section faces upward; the second manipulator mechanism transfers the ladder pipe from the loading station to the drilling station.

3. The method for assembling the front foot of a metal stepladder according to claim 1, characterized in that: In the horizontal drilling step, the horizontal drilling mechanism includes a ladder pipe limit seat, a horizontal drilling and tapping device, a horizontal punching device, and a clamping assembly; the horizontal drilling and tapping device and the horizontal punching device are located on one side of the ladder pipe limit seat, and the clamping assembly is arranged on the other side of the ladder pipe limit seat. When the horizontal drilling mechanism detects that the ladder pipe is placed on the ladder pipe limit seat, the clamping assembly presses the ladder pipe in the ladder pipe limit seat, and the horizontal drilling and tapping device and the horizontal punching device drill and tap or / and punch holes at the preset drilling position of the ladder pipe.

4. The method for assembling the front foot of a metal stepladder according to claim 1, characterized in that: In the steps of adding and squeezing the foot cover, the foot cover installation mechanism includes a magazine slot for conveying the foot cover, a reciprocating pusher arranged in the magazine slot, a power device for driving the reciprocating pusher to slide in the magazine slot, and a pushing assembly for pushing the foot cover out of the magazine slot and into the bottom end of the ladder tube; the magazine slot is provided with at least one discharge port and a feed port; The extrusion deformation mechanism includes an extrusion block, an extrusion block Z-axis expansion and contraction device that drives the extrusion block to expand and contract up and down along the Z-axis direction, and an extrusion block Y-axis sliding device that drives the extrusion block Z-axis expansion and contraction device to move left and right along the Y-axis direction. The extrusion block is located above the foot cover mounting mechanism. The foot sleeve enters the material box slot from the feed inlet and is pushed to the discharge outlet by the reciprocating pusher. When it is detected that the ladder pipe out of the discharge outlet is in place, the push-up assembly extends to push the foot sleeve out of the material box slot and push it into the bottom end of the ladder pipe. When the foot sleeve is installed at the bottom end of the ladder pipe, the extrusion block is moved to a preset position above the ladder pipe by the extrusion block shaft sliding device, and then driven downward by the extrusion block Z-axis telescopic device to extrude it. The ladder pipe is partially concave and deformed at the preset position to fix the foot sleeve at the bottom end of the ladder pipe.

5. The method for assembling the front foot of a metal stepladder according to claim 1, characterized in that: In the step of finalizing the front foot ladder accessories, the front foot ladder limiting fixture includes a base plate, a first ladder tube limiting seat, a second ladder tube limiting seat, a crossbar limiting seat, a foot sleeve positioning seat, a pedal limiting seat, and a locking piece; the first ladder tube limiting seat and the second ladder tube limiting seat are arranged in an eight-shaped shape on the base plate, and the crossbar limiting seat and the pedal limiting seat are arranged between the first ladder tube limiting seat and the second ladder tube limiting seat; the first ladder tube limiting seat is fixedly mounted on the base plate, and the second ladder tube limiting seat is movably mounted on the base plate at a position close to or away from the first ladder tube limiting seat; foot sleeve positioning seats are provided at the ends of the first ladder tube limiting seat and the second ladder tube limiting seat, for limiting the starting position of the foot sleeve at the bottom of the front foot ladder; After the foot cover is installed, the ladder tube is automatically installed on the first ladder tube limit seat and the second ladder tube limit seat by the second manipulator mechanism, and is distributed in an eight-shaped shape. Then, the cross bar, top pedal and other accessories are manually installed between the two ladder tubes. There is a U-shaped opening at each end of the cross bar, which is used to clip into the ladder tubes at both ends. Then the second ladder tube limit seat is slid close to the first ladder tube limit seat, and the position of the second ladder tube limit seat is fixed by a locking piece, so that the front foot ladder is installed completely according to the preset angle and position, and limited on the front foot ladder limit fixture, which is convenient for the subsequent vertical drilling process, that is, the cross bar and the ladder tube are drilled and locked by the existing vertical drilling device, so as to realize the transformation of the cumbersome fastener positioning process into a simple direct drilling process.

6. The method for assembling the front foot of a metal stepladder according to claim 1, characterized in that: During the vertical drilling and tapping step, the Y-axis transport device transfers the entire front foot ladder limiting fixture to the vertical drilling and tapping station. At this time, the ladder tubes on the front foot ladder limiting fixture are distributed in an eight-shaped shape. The crossbar and top pedal are locked on the ladder tubes through the vertical drilling and tapping device to complete the overall fixation of the front foot ladder frame.

7. The method for assembling the front foot of a metal stepladder according to claim 1, characterized in that: After vertical drilling and tapping, the tool box installation step is also included; In the tool box installation step, the tool box is clamped and transferred to the preset tool box limiting jig by the tool box installation mechanism, and the left and right push handle mechanisms on the tool box limiting jig clamp and fix the tool box. The tool box limiting jig is pushed to the side of the front foot ladder limiting jig that has completed the vertical drilling and tapping process, and the tool box is inserted into the top of the two ladder pipes arranged in an eight-shaped shape. The tool box is fixed to the top of the ladder pipe by the fasteners on the drilling and tapping device to complete the installation of the tool box.

8. The method for assembling the front foot of a metal stepladder according to claim 7, characterized in that: The tool box installation mechanism includes a tool box loading device for conveying the tool box, a third manipulator for grabbing the tool box, a tool box limiting fixture for fixing the position of the tool box, a tool box clamping hand for clamping the tool box on the tool box limiting fixture, a tool box pushing device for pushing the tool box to the top of the two ladder tubes, and a tool box drilling and tapping device for locking the tool box on the two ladder tubes; if the direction of the tool box needs to be adjusted, the tool box installation mechanism also includes a rotating tool for adjusting the direction of the tool box; The third robot is driven by a power drive to move along the X-axis and Z-axis directions, so that it transfers the loading device or the rotary tooling to the tool box limiting fixture, and the tool box clamp is fixed to the tool box limiting fixture; the tool box pushing device is driven by a power drive to move along the Y-axis and Z-axis directions. At this time, after adjusting the height direction of the Z-axis by the tool box pushing device, the tool box is transported along the Y-axis direction until it is inserted into the top of the two ladder tubes. The tool box drilling and tapping device is located on the top of the ladder tube and the tool box. The tool box drilling and tapping device rotates downward along the Z-axis direction, and the tool box is locked on the two ladder tubes by fasteners to complete the installation of the tool box.

9. The method for assembling the front foot of a metal stepladder according to claim 1, characterized in that: Before loading, the method further includes a crossbar pre-installation step: in the crossbar pre-installation step, concave connectors for quick installation are provided at both ends of the crossbar, and the concave connectors are fixed to both ends of the crossbar by a crossbar pre-installation mechanism; The crossbar pre-installation mechanism includes a crossbar limiting fixture for fixing the crossbar, a crossbar pressing device for pressing the crossbar, a connector feeding device for conveying the concave connector, a connector limiting seat for limiting the position of the concave connector, an anti-dislocation device for preventing the concave connector from slipping, and a connector pushing device for pushing and fixing the concave connector at both ends of the crossbar; First, press and fix the cross bar on the cross bar limiting fixture. The connector feeding device delivers the concave connector to the connector limiting seat through the feeding trough. Then the connector pushing device pushes the concave connector and fixes it on both ends of the cross bar to complete the pre-installation process of the cross bar.

10. The method for assembling the front foot of a metal stepladder according to claim 1, characterized in that: Before loading, the method further includes the step of pre-installing the top tread through a pipe and marking: in the step of pre-installing the top tread through a pipe, the top tread is provided with a pivot pipe for pivotally connecting between the two ladder pipes, the pivot pipe is inserted into the top tread by a top tread through a pipe-marking mechanism, and is rotatably fixed on the top tread; The top pedal pipe-threading and dotting mechanism includes a pedal limiting jig, a material guide trough, a rotating frame, a guide device, and a downward pressure limiting device; the top pedal is placed and limited on the pedal limiting jig, and the top pedal is provided with a mounting hole for installing the pivot tube; the material guide trough is provided with a discharge port for a pivot tube to pass through and a material guide slope for providing gravity power to the discharge port; the rotating frame is arranged on one side of the discharge port, and is used to rotate and transport the pivot tube of the discharge port to a preset height of the mounting hole; the guide device inserts the pivot tube on the rotating frame into the mounting hole of the top pedal from the horizontal direction, and reserves pipe ports of the same length on both sides of the top pedal; the downward pressure device presses down on the pipe ports on both sides of the top pedal in the vertical direction to deform the pipe ports, thereby limiting the range of movement of the top pedal in the pivot tube.

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