A method of assembling a front ladder of a metal A-frame ladder

Abstract

The application discloses a metal A-frame ladder front ladder assembling method, which is assembled by using a metal A-frame ladder front ladder assembling device and specifically comprises the following steps: horizontally transferring a ladder pipe to a horizontal drilling station by a ladder pipe feeding mechanism, and turning over the ladder pipe at the end of conveying to a vertical state; transferring the ladder pipe into a ladder pipe limiting seat by a first mechanical arm, and drilling and tapping or / and punching by a horizontal drilling mechanism; feeding a foot cover into the ladder pipe from the top by a foot cover mounting mechanism, and applying external force extrusion to a preset position of the ladder pipe by an extrusion deformation mechanism, so that the ladder pipe is locally concave and deformed; grabbing and tilting the ladder pipe by a second mechanical arm, and placing the ladder pipe in an eight-shaped form on a front ladder limiting fixture; placing a cross rod and a top pedal between the two ladder pipes; transferring the whole front ladder limiting fixture to a vertical drilling and tapping station to drill and tap, and completing the frame fixing of the front ladder. The assembling method has the characteristics of less labor, simple operation, automatic processing, high efficiency and the like, so as to satisfy the maximization of production benefit.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal piece processing and assembling, in particular to an automatic feeding, drilling, extruding and deforming production line for the front ladder leg of a metal folding ladder. BACKGROUND

[0002] With the development of society and industry, people's living and office space is relatively reduced, and most of the general household appliances require simple operation and easy folding and moving to reduce the occupied space. The metal folding ladder is widely used by the public due to its simple structure and easy storage and carrying after folding.

[0003] In combination Figure 1 , the metal folding ladder includes a front ladder A and a rear ladder B movably connected to the front ladder, and the front ladder and the rear ladder are usually switched between an unfolded state and a folded state to meet the use needs of people at different periods. The front ladder refers to a climbable structure connecting and supporting a plurality of steps between two ladder pipes, and is the core component of the metal ladder. The two ladder pipes are arranged in a figure-eight shape to support the two sides of the front ladder, and the step refers to a horizontal rod on the front ladder for stepping, which is usually composed of a plurality of inconsistent horizontal rods with gradually narrowing lengths. The bottom of the front ladder is usually provided with an anti-skid foot sleeve for protecting the foot pipe and preventing the ladder from sliding, and the middle and upper part of the front ladder is usually provided with a top step for providing a user with a place to sit or a large area to step on; and the top of the front ladder is usually provided with a tool box for placing work accessories.

[0004] Due to the unique shape and structure of the front ladder, it often needs to go through metal surface treatment processes such as ladder pipe figure-eight feeding arrangement, drilling, punching, extruding and deforming, and needs to install an anti-skid foot sleeve at the bottom of the two ladder pipes, a top step at the middle and upper part of the two ladder pipes, and a tool box at the top of the two ladder pipes. In production practice, these processes are usually completed by manual operation, and some automatic processing methods are used in individual processes, but still require multiple people to operate, such as feeding and discharging, manual drilling and punching, extruding and deforming, pre-assembly of accessories such as horizontal rods and top steps, and installation of accessories such as anti-skid foot sleeves, horizontal rods, top steps and tool boxes.

[0005] In order to further reduce the cost and improve the processing efficiency, an automatic processing equipment is designed, which can realize pre-installation of accessories, automatic figure-eight feeding arrangement of ladder pipes, automatic drilling and punching, automatic extruding and deforming, and automatic installation of various accessories. The equipment production line has the characteristics of less labor, simple operation, automatic processing and high efficiency to maximize production efficiency.

[0006] Therefore, we propose a method for assembling the front ladder of a metal ladder to solve the problems mentioned above. SUMMARY

[0007] In order to overcome the deficiencies of the prior art, the purpose of the present application is to provide a metal ladder front ladder assembly method.

[0008] The purpose of the present application is achieved by the following technical scheme: a metal ladder front ladder assembly method, which is assembled by a metal ladder front ladder assembly device, and specifically includes the following steps:

[0009] Feeding: the ladder pipe is horizontally transferred to the front of the horizontal drilling station by the ladder pipe feeding mechanism, and then the ladder pipe at the end of the conveying is turned from a horizontal state to an upright state;

[0010] Horizontal drilling: the first manipulator clamps the ladder pipe in an upright state, horizontally transfers it to the ladder pipe limiting seat, and clamps and fixes its position, and then drills and / or punches the inner side of the ladder pipe through the horizontal drilling mechanism;

[0011] Foot sleeve installation and extrusion positioning: after completing the horizontal drilling, the foot sleeve is inserted into the end of the ladder pipe through the foot sleeve installation mechanism, and then the ladder pipe is locally recessed and deformed by applying external force to the preset position of the ladder pipe through the extrusion deformation mechanism, so as to fix and position the foot sleeve at the end of the ladder pipe;

[0012] Front ladder accessory shaping: the second manipulator grabs and tilts the two ladder pipes after installing the foot sleeve, respectively, and places them in an eight-character shape at the preset position of the front ladder limiting jig, and manually places the cross bar and the top step between the two ladder pipes according to the preset position of the front ladder limiting jig, to complete the frame installation of the front ladder;

[0013] Vertical drilling: the Y-axis conveying device transfers the entire front ladder limiting jig to the vertical drilling station, and the cross bar and the top step are locked on the ladder pipe by the vertical drilling device, to complete the overall fixation of the front ladder frame.

[0014] Further, in the feeding step, the ladder pipe feeding mechanism includes an X-axis conveying device for horizontally conveying the ladder pipe, a turning device for turning the ladder pipe horizontally by 90°, and a first manipulator mechanism for transferring the ladder pipe from the feeding station to the drilling station, and the turning 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 in the horizontal direction on the X-axis conveying device, the turning device is rotated after the X-axis conveying device conveys the ladder pipe to the turning device, so that the short side of the cross section of the ladder pipe faces upward; the first manipulator mechanism transfers the ladder pipe from the feeding station to the drilling station.

[0015] Further, in the horizontal drilling step, the horizontal drilling mechanism comprises a ladder pipe limiting seat, a horizontal drilling device, a horizontal punching device, and a pressing assembly; the horizontal drilling device and the horizontal punching device are located on one side of the ladder pipe limiting seat, and the pressing assembly is arranged on the other side of the ladder pipe limiting seat; when the horizontal drilling mechanism detects that the ladder pipe is placed on the ladder pipe limiting seat, the pressing assembly presses the ladder pipe in the ladder pipe limiting seat, and the horizontal drilling device and the horizontal punching device drill and / or punch at the preset drilling position of the ladder pipe.

[0016] Further, in the step of installing and extruding the foot cover, the foot cover installation mechanism comprises a magazine slot for conveying the foot cover, a reciprocating pusher arranged in the magazine slot, a power device for sliding the reciprocating pusher in the magazine slot, and a pushing and ejecting assembly for pushing the foot cover out of the magazine slot and into the bottom end of the ladder pipe; the magazine slot is provided with at least one discharge port and a feeding port;

[0017] The extrusion deformation mechanism comprises an extrusion block, an extrusion block Z-axis extension and retraction device for driving the extrusion block to extend and retract along the Z-axis direction, and an extrusion block Y-axis sliding device for driving the extrusion block Z-axis extension and retraction device to move left and right along the Y-axis direction; the extrusion block is located above the foot cover installation mechanism;

[0018] The foot cover enters the magazine slot from the feeding port and is pushed to the discharge port by the reciprocating pusher; when it is detected that the discharge port is in place, the pushing and ejecting assembly is extended to push the foot cover out of the magazine slot and into the bottom end of the ladder pipe; when the foot cover 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 is driven downward by the extrusion block Z-axis extension and retraction device; the ladder pipe is locally recessed and deformed at the preset position to fix and limit the foot cover at the bottom end of the ladder pipe.

[0019] Further, in the step of shaping the front ladder accessory, the front ladder limiting jig comprises a bottom plate, a first ladder pipe limiting seat, a second ladder pipe limiting seat, a crossbar limiting seat, a foot cover positioning seat, a step limiting seat, and a lock buckle; the first ladder pipe limiting seat and the second ladder pipe limiting seat are arranged in a spreader shape on the bottom plate, and the crossbar limiting seat and the step limiting seat are arranged between the first ladder pipe limiting seat and the second ladder pipe limiting seat; the first ladder pipe limiting seat is fixedly installed on the bottom plate, and the second ladder pipe limiting seat is movably installed on the bottom plate between positions close to and away from the first ladder pipe limiting seat; the ends of the first ladder pipe limiting seat and the second ladder pipe limiting seat are provided with the foot cover positioning seat for limiting the starting position of the foot cover at the bottom of the front ladder;

[0020] After the installation of the foot cover, the ladder pipe is automatically installed on the first ladder pipe limiting seat and the second ladder pipe limiting seat by the second mechanical hand mechanism, and is distributed in a spread shape, then the cross bar, the top pedal and other accessories are installed between the two ladder pipes, finally the second ladder pipe limiting seat is slid close to the first ladder pipe limiting seat, and the position of the second ladder pipe limiting seat is fixed by the lock buckle, so that the front ladder is completely installed according to the preset angle and position and is limited on the front ladder limiting jig.

[0021] Further, in the vertical drilling step, the Y-axis conveying device transfers the whole front ladder limiting jig to the vertical drilling station, at this time, the ladder pipes on the front ladder limiting jig are distributed in a spread shape, and the cross bar and the top pedal are locked on the ladder pipes by the vertical drilling device, to complete the overall fixing of the frame of the front ladder.

[0022] Further, after the vertical drilling, a tool box installation step is further included;

[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, the left and right pushing 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 which has completed the vertical drilling process, and the tool box is inserted into the top of the two ladder pipes arranged in a spread shape, the tool box is fixed on the top of the ladder pipes by the fastener on the drilling device, to complete the installation of the tool box.

[0024] Further, the tool box installation mechanism includes a tool box feeding device for conveying the tool box, a third mechanical hand for grabbing the tool box, a tool box limiting jig for fixing the position of the tool box, a tool box clamping hand for clamping the tool box on the tool box limiting jig, a tool box pushing device for pushing the tool box to the top of the two ladder pipes, and a tool box drilling 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 further includes a rotating tool for adjusting the direction of the tool box;

[0025] The third mechanical hand is driven by a power driving part to move along the X-axis and Z-axis directions, so as to transfer the feeding device or the rotating tool on the tool box limiting jig, and the tool box is fixed on the tool box limiting jig by the tool box clamping hand; the tool box pushing device is driven by a power driving part 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 conveyed along the Y-axis direction until it is inserted into the top of the two ladder pipes, the tool box drilling device is located at the top of the ladder pipes and the tool box, the tool box drilling device rotates downward along the Z-axis direction, the tool box is locked on the two ladder pipes by the fastener, and the installation of the tool box is completed.

[0026] Further, before feeding, a step of preloading the crossbar is further included: in the step of preloading the crossbar, the two ends of the crossbar are provided with concave connectors for quick installation, and the concave connectors are fixed at the two ends of the crossbar through a crossbar preloading mechanism;

[0027] The crossbar preloading mechanism comprises a crossbar limiting jig for fixing the crossbar, a crossbar pressing device for pressing the crossbar, a connector feeding device for feeding the concave connectors, a connector limiting seat for limiting the position of the concave connectors, an anti-disengagement device for preventing the concave connectors from slipping off, and a connector pushing device for pushing and fixing the concave connectors at the two ends of the crossbar.

[0028] First, the crossbar is pressed and fixed on the crossbar limiting jig, the connector feeding device feeds the concave connectors to the connector limiting seat through a feeding groove, and then the connector pushing device pushes and fixes the concave connectors at the two ends of the crossbar, thereby completing the preloading process of the crossbar.

[0029] Further, before feeding, a step of preloading the crossbar is further included: in the step of preloading the crossbar, the two ends of the crossbar are provided with concave connectors for quick installation, and the concave connectors are fixed at the two ends of the crossbar through a crossbar preloading mechanism;

[0030] The crossbar preloading mechanism comprises a crossbar limiting jig for fixing the crossbar, a crossbar pressing device for pressing the crossbar, a connector feeding device for feeding the concave connectors, a connector limiting seat for limiting the position of the concave connectors, an anti-disengagement device for preventing the concave connectors from slipping off, and a connector pushing device for pushing and fixing the concave connectors at the two ends of the crossbar.

[0031] Compared with the prior art, the beneficial effects of the present application are:

[0032] 1. In order to further reduce the cost and improve the processing efficiency, an automatic processing equipment is specially designed, which can realize pre-installation of parts, automatic eight-shaped feeding arrangement of ladder pipes, automatic drilling and tapping and punching, automatic extrusion deformation, and automatic installation of various parts production lines. The equipment production line has the characteristics of less labor, simple operation, automatic processing, high efficiency and the like, so as to maximize the production benefit.

[0033] 2、Specifically, the two ladder pipes are arranged in a splayed shape in the front ladder limiting jig, and other cross bars, foot sleeves and other accessories are also pre-assembled on the front ladder limiting jig, the front ladder limiting jig is provided with various limiting seats for the accessories required by the front ladder A, so that the subsequent drilling and fixing process is facilitated, through the operation of each mechanism on the production line of the application, the above-mentioned accessories complete the pre-assembly, pre-drilling and extrusion deformation to realize the automatic installation of scattered accessories, and the production efficiency is improved.

[0034] 3、The application is conveyed to the notch in the rotating disc in turn by the belt device on the feeding station, and then the turning device is turned, so that the horizontally lying ladder pipe is turned by a certain angle to be turned to an upright state, on the one hand, the second mechanical hand mechanism is convenient to clamp, on the other hand, the direction of the pre-turned ladder pipe is convenient for direct construction of the drilling station.

[0035] 4、According to the installation needs of the cross bar and the top step, fastening holes or mounting holes are pre-formed on the ladder pipe, a plurality of horizontal drilling devices and / or horizontal punching devices are arranged in the middle of the mounting table, in order to improve the adaptability of assembling different products of the ladder, the horizontal drilling device and / or the horizontal punching device of the application can be provided with a plurality of axial movement devices (not marked in the drawing) such as X-axis, Y-axis and Z-axis, which are used to drive the horizontal drilling device and / or the horizontal punching device to move to the required position for drilling, so as to improve the processing adaptability and efficiency of the station.

[0036] 5、The existing foot sleeve usually needs manual installation, repeated adjustment of the installation position, and additional manual extrusion shaping process after installation, the assembly efficiency is extremely low, the length of the ladder pipe is large, the installation and transportation are not convenient, a larger processing place is needed, which is not conducive to mass production of products. Therefore, the application inserts the automatic assembly process of the foot sleeve in the drilling process, so that the entire assembly of the foot sleeve can be completed before being transferred to the splayed front ladder assembly station, which specifically includes two steps of inserting and assembling the foot sleeve and extruding and deforming the ladder pipe. The above-mentioned processing steps are completely completed by automatic equipment without manual intervention, which greatly improves the production efficiency and avoids the tolerance error of manual assembly. In addition, the mechanism is located on one side of the upper part of the mounting table, which reasonably utilizes the positions on both sides of the drilling station, improves the utilization efficiency of the site, and improves the overall production and assembly efficiency.

[0037] 6、In order to further improve the efficiency and reasonably utilize the processing space of the factory, the application specifically improves the feeding efficiency of the foot sleeve by designing the cooperation between the in-out feeding position in the material box groove and the back-and-forth pushing hand structure, and in combination with the cooperation of the ladder pipe turning device, the foot sleeve installation time of a single ladder is shortened as a whole, which greatly releases manpower and improves the assembly efficiency.

[0038] 7、The present application sets an angle adjusting device in the mechanical hand mechanism, when the hand device clamps the ladder pipe, it turns a preset angle outward or inward, the angle adjusting is realized and completed through the setting of the cylinder stroke and the two installation piece pivot connection, the structure is simple, can realize two-way adjustment, realizes the automatic assembly of the X-shaped ladder leg.

[0039] 8、The present application designs a Y-axis conveying device, the X-shaped front foot ladder shaping station and the vertical drilling and tapping station share a Y-axis conveying device, the Y-axis conveying device has two layers of conveying belts, the front foot ladder limiting fixture is circulated between the two layers of conveying belts, realizes the circulation installation of the X-shaped front foot ladder, improves the transportation efficiency of the limiting fixture, and improves the production efficiency.

[0040] 9、The present application designs a tool box mounting mechanism, clamps and transfers the tool box to the preset tool box limiting fixture, the left and right pushing mechanism on the tool box limiting fixture clamps and fixes the tool box, the tool box limiting fixture is pushed to the side of the front foot ladder limiting fixture which has completed the vertical drilling and tapping process, and the tool box is inserted into the top of the two X-shaped arranged ladder pipes, the tool box is fixed on the top of the ladder pipe through the fastener on the drilling and tapping device, and the installation of the tool box is completed.

[0041] 10、The present application designs a cross rod preloading mechanism and a top pedal pipe penetrating and dotting mechanism, completes the preloading of the connecting piece and the pivot on the cross rod and the top pedal, solves the problem of releasing manpower through the automatic equipment, and improves the production efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 It is a structural schematic view of the metal folding X-shaped ladder in the prior art;

[0043] Figure 2 It is a structural schematic view of the front foot ladder in the metal folding X-shaped ladder;

[0044] Figure 3 It is an assembly direction schematic view of the front foot ladder assembly process of the metal X-shaped ladder;

[0045] Figure 4 It is a structural schematic view of the ladder pipe feeding mechanism, the horizontal drilling mechanism, the foot cover mounting mechanism, the extrusion deformation mechanism and the second mechanical hand mechanism;

[0046] Figure 5 It is a structural schematic view of the ladder pipe feeding mechanism;

[0047] Figure 6 It is Figure 5 It is an enlarged schematic view of a in the;

[0048] Figure 7Structure schematic view of horizontal drilling mechanism, foot cover installation mechanism, extrusion deformation mechanism and second mechanical hand mechanism of preferred embodiment of the present application;

[0049] Figure 8 Enlarged schematic view of first mechanical hand mechanism of preferred embodiment of the present application;

[0050] Figure 9 For Figure 8 Enlarged schematic view at b;

[0051] Figure 10 Enlarged schematic view of second mechanical hand mechanism of preferred embodiment of the present application;

[0052] Figure 11 Structure schematic view of drilling mechanism and foot cover installation mechanism of preferred embodiment of the present application;

[0053] Figure 12 For Figure 11 Enlarged schematic view at c;

[0054] Figure 13 For Figure 12 Partial enlarged schematic view;

[0055] Figure 14 For Figure 13 Enlarged schematic view at d;

[0056] Figure 15 Structure schematic view of drilling mechanism and foot cover installation mechanism of preferred embodiment of the present application from another angle;

[0057] Figure 16 For Figure 15 Partial enlarged schematic view;

[0058] Figure 17 Structure schematic view of front foot ladder limiting fixture of preferred embodiment of the present application;

[0059] Figure 18 Structure schematic view of vertical drilling and tapping device of preferred embodiment of the present application;

[0060] Figure 19 Structure schematic view of tool box installation mechanism of preferred embodiment of the present application;

[0061] Figure 20 Structure schematic view of tool box installation mechanism without drilling and tapping device of preferred embodiment of the present application;

[0062] Figure 21 For Figure 20 Enlarged schematic view at e;

[0063] Figure 22 Structure schematic view of tool box drilling and tapping device and tool box clamping hand of preferred embodiment of the present application;

[0064] Figure 23 Structure diagram of the crossbar of the preferred embodiment of the present application;

[0065] Figure 24 Structure diagram of the crossbar preloading mechanism of the preferred embodiment of the present application;

[0066] Figure 25 Structure diagram of the crossbar preloading mechanism of the preferred embodiment of the present application; Figure 24 Enlarged diagram at f;

[0067] Figure 26 Structure diagram of the top pedal pipe punching mechanism of the preferred embodiment of the present application;

[0068] Figure 27 Structure diagram of the top pedal pipe punching mechanism of the preferred embodiment of the present application from another angle;

[0069] In the figure: 1, ladder pipe loading mechanism; 11, X-axis conveying device; 12, turning device; 121, rotating disc; 122, notch; 13, first mechanical hand mechanism; 131, first clamping hand device; 132, first clamping hand Z-axis lifting device; 133, first clamping hand Y-axis moving device;

[0070] 2, horizontal drilling mechanism; 21, ladder pipe limiting seat; 22, horizontal drilling device; 23, horizontal punching device; 24, pressing assembly; 241, pressing block; 242, rotary pressing device;

[0071] 3, foot cover installation mechanism; 31, material box groove; 311, discharge port; 312, feeding port; 32, reciprocating push hand; 33, power device; 34, pushing and ejecting assembly; 35, ladder pipe overturning 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 mechanical hand mechanism; 51, second clamping hand device; 52, second clamping hand Z-axis lifting device; 53, second clamping hand Y-axis moving device; 54, angle adjusting device; 541, first mounting piece; 542, second mounting piece; 543, adjusting cylinder; 544, pivot; 55, position sensor;

[0074] 6, front ladder limiting jig; 61, bottom plate; 62, first ladder pipe limiting seat; 63, second ladder pipe limiting seat; 64, crossbar limiting seat; 65, foot cover positioning seat; 66, pedal limiting seat; 67, lock catch;

[0075] 7, vertical drilling device; 71, side clamping assembly; 72, vertical drilling assembly; 73, guide seat;

[0076] 8, tool box mounting mechanism; 81, tool box feeding device; 82, third manipulator; 83, tool box limiting jig; 84, tool box clamping hand; 85, tool box pushing device; 86, tool box drilling device; 87, rotating tool;

[0077] 9, cross rod preloading mechanism; 91, cross rod limiting jig; 92, cross rod pressing device; 93, connecting piece feeding device; 94, connecting piece limiting seat; 95, anti-dislocation device; 96, connecting piece pushing device;

[0078] 10, top pedal pipe punching mechanism; 101, pedal limiting jig; 102, guide chute; 103, rotating frame; 104, guide punching device; 105, downward limiting device;

[0079] 111, Y-axis conveying device;

[0080] A, front ladder; A1, ladder pipe; A2, cross rod; A21, concave connecting piece; A3, foot cover; A4, top pedal; A5, tool box; B, rear ladder. DETAILED DESCRIPTION

[0081] In the following, the present application will be further described in conjunction with the drawings and specific embodiments, and it should be noted that the following described embodiments or technical features can be combined in any manner to form new embodiments without conflict.

[0082] As shown in the drawings, Figure 1 The metal folding ladder of the present application comprises a front ladder A and a rear ladder B connected to the front ladder A, and the front ladder A and the rear ladder B are usually switched between an unfolded state and a folded state to meet the use requirements of people at different periods. As shown in the drawings, Figure 2 The front ladder A of the present application refers to a climbable structure connecting and supporting a plurality of pedals between two ladder pipes, and is the core component of the metal ladder. The two ladder pipes A1 are arranged in a figure-eight shape and serve as the two side support portions of the front ladder. The pedal refers to the cross rod A2 on the front ladder A for stepping, and is usually composed of a plurality of inconsistent cross rods with gradually narrowing lengths. The bottom of the front ladder A is usually provided with a foot cover A3 for protecting the foot pipe and preventing the ladder from sliding. The upper part of the front ladder A is usually provided with a top pedal A4, and the top of the front ladder A is usually provided with a tool box A5 for placing work accessories.

[0083] The metal ladder front ladder assembly method is a core processing procedure of a metal ladder front ladder A, main accessories and structures of the front ladder A are built through a production line of the application in advance, so that subsequent assembly of a rear ladder is facilitated, and excessive tolerance or low efficiency caused by manual assembly of all accessories is avoided.

[0084] As shown in Figures 3-27 A metal ladder front ladder assembly method is assembled by using a metal ladder front ladder assembly device, the metal ladder front ladder assembly device is provided with a crossbar pre-assembly station, a pedal pipe penetrating and dotting pre-assembly station, a ladder pipe feeding station, a horizontal drilling station, a foot cover installation station, an eight-shaped front ladder shaping station, a vertical drilling and tapping station, and a tool box installation station.

[0085] The eight-shaped front ladder shaping station and the vertical drilling and tapping station share a Y-axis conveying device, the Y-axis conveying device has two layers of conveying belts, the front ladder limiting fixture is circulated and transferred between the two layers of conveying belts, the circulation installation of the eight-shaped front ladder is realized, the transfer efficiency of the limiting fixture is improved, and the production efficiency is improved.

[0086] The metal ladder front ladder assembly method comprises the following steps:

[0087] Feeding: the ladder pipe A1 is horizontally transferred to the front of the horizontal drilling station by the ladder pipe feeding mechanism 1, and then the ladder pipe A1 at the end of the conveying is flipped from a horizontal state to an upright state;

[0088] Horizontal drilling: the first mechanical hand clamps the ladder pipe A1 in the upright state, horizontally transfers the ladder pipe A1 to the ladder pipe limiting seat, and clamps and fixes the position of the ladder pipe A1, and then drills and taps or / and punches the inner side of the ladder pipe A1 by the horizontal drilling mechanism;

[0089] Foot cover installation and extrusion positioning: after the horizontal drilling is completed, the foot cover A3 is inserted into the end of the ladder pipe by the foot cover installation mechanism, and then the extrusion deformation mechanism is used to apply external force to the preset position of the ladder pipe, so that the local concave deformation of the ladder pipe A1 is formed, so that the foot cover is fixed and positioned at the end of the ladder pipe A1;

[0090] Front ladder accessory shaping: the second mechanical hand clamps and tilts the two ladder pipes A1 after the installation of the foot cover, and places them in an eight-shaped manner at the preset position of the front ladder limiting fixture, and then the crossbar A2 and the top pedal A4 are placed between the two ladder pipes A1 according to the preset position of the front ladder limiting fixture, so that the frame installation of the front ladder A is completed;

[0091] Vertical drilling and tapping: the conveying device transfers the entire front ladder limiting fixture to the vertical drilling and tapping station, and then the crossbar A2 and the top pedal A4 are locked on the ladder pipe A1 by the vertical drilling and tapping device, so that the frame of the front ladder A is fixed as a whole.

[0092] The horizontal drilling station, the foot sleeve adding station and the eight-shaped front foot ladder shaping station share a second mechanical hand mechanism, which is used for grabbing, transferring and steering the ladder pipe A1 between the stations according to the needs of the stations.

[0093] The two ladder pipes A1 are arranged in an eight-shaped manner in the front foot ladder limiting jig 6, and other cross bars A2, foot sleeves A3, top pedals A4, tool boxes A5 and other accessories are also pre-assembled on the front foot ladder limiting jig 6. The front foot ladder limiting jig 6 is provided with various limiting seats of the accessories required by the front foot ladder A, so that the subsequent drilling and fixing process is facilitated. Through the operation of each mechanism on the production line, the above-mentioned accessories complete the position pre-assembly, pre-drilling and extrusion deformation to realize the automatic installation of the scattered accessories, and the production efficiency is improved.

[0094] As a further preferred scheme, in the step of feeding, the ladder pipe feeding mechanism 1 comprises an X-axis conveying device 11 for conveying the ladder pipe A1 horizontally, a steering device 12 for steering the ladder pipe A1 horizontally by 90°, and a first mechanical hand mechanism 13 for transferring the ladder pipe A1 from the feeding station to the drilling station. 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, the X-axis conveying device 11 conveys the ladder pipes A1 to the steering device 12, and the steering device 12 is rotated to make the short side of the cross section of the ladder pipe A1 face upward. The first mechanical hand mechanism 13 transfers the ladder pipe A1 from the feeding station to the drilling station.

[0095] The steering device 12 is provided with a rotating disc 121, and the periphery of the rotating disc 121 is provided with a plurality of notches 122 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, so that the ladder pipe A1 is turned from a horizontal state to an upright state. The power device includes but is not limited to a motor, a belt transmission device and other existing transmission devices.

[0096] The first mechanical hand mechanism 13 comprises a first clamping hand device 131, a first clamping Z-axis lifting device 132 for moving the clamping hand device along the Z-axis direction, and a first clamping Y-axis moving device 133 for moving the clamping hand Z-axis lifting device along the Y-axis direction.

[0097] In the feeding station, the ladder pipes A1 are conveyed to the notches 122 in the rotating disc 121 in turn by the belt device, and then the steering device 12 is rotated. The horizontally lying ladder pipe A1 is steered by a certain angle, so as to be turned to an upright state. On the one hand, it is convenient for the first mechanical hand mechanism 13 to clamp, and on the other hand, it is convenient for the drilling station to directly construct by pre-turning the direction of the ladder pipe A1.

[0098] As a further preferred solution, in the step of horizontal drilling, the horizontal drilling mechanism 2 comprises a ladder pipe limiting seat 21, a horizontal drilling device 22, a horizontal punching device 23, and a pressing assembly 24; the horizontal drilling device 22 and the horizontal punching device 23 are located on one side of the ladder pipe limiting seat 21, and the pressing assembly 24 is arranged on the other side of the ladder pipe limiting seat 21; when the horizontal drilling mechanism 2 detects that the ladder pipe A1 is placed on the ladder pipe limiting seat 21, the pressing assembly 24 presses the ladder pipe A1 in the ladder pipe limiting seat 21, and the horizontal drilling device 22 and the horizontal punching device 23 drill and / or punch at the preset drilling position of the ladder pipe A1.

[0099] The pressing assembly 24 comprises a pressing block 241 and a rotary pressing device 242 in transmission connection with the pressing block 241, which drives the pressing block 241 to switch between the pressing state of the ladder pipe and the loosening and moving away state of the ladder pipe.

[0100] According to the installation needs of the cross rod A2 and the top pedal A4, fastening holes or mounting holes are pre-formed on the ladder pipe A1, and a plurality of horizontal drilling devices 22 and / or horizontal punching devices 23 are arranged in the middle of the mounting table, in order to improve the adaptability of assembling different products of the ladder, the horizontal drilling device 22 and / or the horizontal punching device 23 of the present application can be provided with a plurality of axial movement devices (not marked in the drawing) such as X-axis, Y-axis, Z-axis, etc., for driving the horizontal drilling device 22 and / or the horizontal punching device 23 to move to the required position for drilling, thereby improving the processing adaptability and efficiency of the present station.

[0101] As a further preferred solution, in the step of installing and extruding the foot cover, the foot cover installation mechanism 3 comprises a magazine slot 31 for conveying the foot cover A3, a reciprocating pusher 32 arranged in the magazine slot 31, a power device 33 for driving the reciprocating pusher 32 to slide in the magazine slot 31, and a pushing and ejecting assembly 34 for pushing the foot cover A3 out of the magazine slot 31 and into the bottom end of the ladder pipe A1; the magazine slot 31 is provided with at least one discharge port 311 and a feeding port 312; the foot cover A3 enters the magazine slot 31 from the feeding 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 in the ladder pipe A1, the pushing and ejecting assembly 34 extends to push the foot cover A3 out of the magazine slot 31 and into the bottom end of the ladder pipe A1.

[0102] The extrusion deformation mechanism 4 comprises an extrusion block 41, an extrusion block Z-axis telescopic device 42 for driving the extrusion block 41 to stretch up and down along the Z-axis direction, an extrusion block Y-axis sliding device 43 for driving the extrusion block Z-axis telescopic device 42 to move left and right along the Y-axis direction, and the extrusion block 41 is located above the foot cover mounting mechanism 3; when the foot cover A3 is mounted 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 is driven downward by the extrusion block Z-axis telescopic device 42, so that the ladder pipe A1 is partially recessed and deformed at the preset position to fix and limit the foot cover at the bottom end of the ladder pipe A1.

[0103] The existing foot cover A3 usually needs to be manually installed, and the installation position needs to be repeatedly adjusted. After installation, an additional manual extrusion shaping process is required, so the assembly efficiency is extremely low. Moreover, the length of the ladder pipe A1 is large, which is not convenient for installation and transportation, and a larger processing site is required, which is not conducive to mass production of products. Therefore, the foot cover A3 is automatically assembled in the drilling process, so that the assembly of the entire foot cover A3 can be completed before being transferred to the eight-shaped front ladder assembly station. Specifically, the assembly includes two steps of inserting the foot cover A3 and extruding and deforming the ladder pipe A1. The above processing steps are completely automatically processed by equipment without manual intervention, which greatly improves the production efficiency and avoids the tolerance error of manual assembly. In addition, the mechanism is located on the upper part of one side of the installation table, which reasonably utilizes the positions on both sides of the drilling station, improves the utilization efficiency of the site, and improves the overall production and assembly efficiency.

[0104] In the embodiment, the foot cover mounting mechanism 3 further comprises a ladder pipe turnover device 35 arranged between the two ladder pipe limiting seats 21 and used for taking out the ladder pipe A1 which has completed the drilling process from the ladder pipe limiting seat 21 and turning over to the other ladder pipe limiting seat 21 to wait for the foot cover installation process. Specifically, the ladder pipe turnover device 35 comprises a rotating arm 351, a movable gripper 352 mounted at the end of the rotating arm 351, and a rotating arm Z-axis lifting device 353 for driving the rotating arm 351 to move up and down along the Z-axis direction.

[0105] In order to further improve the efficiency and reasonably utilize the processing space of the factory, the feeding efficiency of the foot cover A3 is improved by matching the in-out feeding position in the material box groove 31 with the structure of the back-and-forth pusher 32, and the foot cover installation time of a single A-frame ladder can be shortened as a whole by combining the cooperation of the ladder pipe turnover device 35, so that the labor is greatly released and the assembly efficiency is improved.

[0106] As a further preferred scheme, in the step of shaping the front ladder accessory, the front ladder limiting jig 6 comprises a bottom plate 61, a first ladder pipe limiting seat 62, a second ladder pipe limiting seat 63, a cross bar limiting seat 64, a foot cover positioning seat 65, a pedal limiting seat 66, and a lock catch 67.

[0107] The first ladder pipe limiting seat 62 and the second ladder pipe limiting seat 63 are arranged in a spreader shape on the bottom plate 61, and the crossbar limiting seat 64 and the pedal limiting seat 66 are arranged between the first ladder pipe limiting seat 62 and the second ladder pipe limiting seat 63; the first ladder pipe limiting seat 62 is fixedly installed on the bottom plate 61, and the second ladder pipe limiting seat 63 is movably installed on the bottom plate 61 at a position close to or away from the first ladder pipe limiting seat 62; the ends of the first ladder pipe limiting seat 62 and the second ladder pipe limiting seat 63 are provided with a foot cover limiting seat 65 for limiting the starting position of the foot cover A3 at the bottom of the front ladder.

[0108] When the foot cover A3 is installed, the ladder pipe A1 is automatically installed on the first ladder pipe limiting seat 62 and the second ladder pipe limiting seat 63 by the second mechanical hand mechanism 5, arranged in a spreader shape, and then the crossbar A2, the top pedal A4 and other accessories are installed between the two ladder pipes A1 by artificial installation, and the crossbar A2 has a U-shaped opening at both ends for clamping into the ladder pipes A1 at both ends, then the second ladder pipe limiting seat 63 is slid close to the first ladder pipe limiting seat 62, and the position of the second ladder pipe limiting seat 63 is fixed by the locking member, so that the front ladder A is completely installed according to the preset angle and position, and is limited on the front ladder limiting jig 6, facilitating the subsequent vertical drilling process, that is, the crossbar A2 and the ladder pipe A1 are drilled and fastened by the existing vertical drilling device 7, realizing the conversion of the complicated fastener positioning process into a simple direct drilling process.

[0109] In this embodiment, specifically, the second mechanical hand mechanism 5 includes a second clamping hand device 51, a second clamping hand Z-axis lifting device 52 for moving the second clamping hand device 51 along the Z-axis direction, a second clamping hand Y-axis moving device 53 for moving the second clamping hand Z-axis lifting device 52 along the Y-axis direction, and an angle adjusting device 54 for adjusting the clamping hand device to a preset angle.

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

[0111] The present application sets an angle adjusting device 54 in the mechanical hand mechanism, when the hand device clamps the ladder pipe A1, it is turned outward or inward by a preset angle, the angle adjusting is realized and completed by setting the cylinder stroke and the two mounting sheet pivot connection, the structure is simple, can realize two-way adjustment, realizes the automatic assembly of the eight-shaped ladder leg.

[0112] In the preferred embodiment of the present embodiment, in order to realize high-precision automatic control of the second mechanical hand mechanism 5, the hand Z-axis lifting device is provided with a plurality of vertically arranged position sensors 55. The vertically arranged position sensor 55 can provide height position control, realize high-precision alignment clamping and transfer work.

[0113] As a further preferred embodiment, in the step of vertical drilling, the Y-axis conveying device 111 transfers the entire front foot ladder limiting jig 6 to the vertical drilling station, at this time, the ladder pipes A1 on the front foot ladder limiting jig 6 are distributed in an eight-shaped manner, the cross bar A2 and the top pedal A4 are locked on the ladder pipes A1 by the vertical drilling device 7, and the frame of the front foot ladder A is fixed as a whole.

[0114] Specifically, the two vertical drilling devices 7 are a group, and the Y-axis conveying device 111 is provided with at least one group of vertical drilling devices 7. In order to improve the vertical drilling efficiency of the production line, three groups of vertical drilling devices 7 are provided in the preferred embodiment, each group of vertical drilling devices 7 is arranged on the two sides of one front foot ladder limiting jig 6, and each vertical drilling device 7 includes a top clamping assembly (not shown in the figure), a side clamping assembly 71, at least one vertical drilling assembly 72, and a guide seat 73. The vertical drilling assembly 72 can be symmetrically distributed up and down, the top clamping assembly is driven by a power driving member to move along the Z-axis direction, the side clamping assembly 71 is driven by a power driving member to move along the X-axis and Z-axis directions, and the vertical drilling device 7 is driven by a power driving member to move along the Y-axis and Z-axis directions. In order to match the angle of the eight-shaped distributed ladder pipes A1 on the front foot ladder limiting jig 6, the guide seat 73 is designed to be distributed in an eight-shaped manner, and the vertical drilling assembly 72 is installed on the guide seat 73, so that the efficiency of the vertical drilling process is greatly improved without the need for turning adjustment.

[0115] As a further preferred embodiment, after vertical drilling, a tool box installation step is further 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 pushing mechanism on the tool box limiting jig 83 clamps and fixes the tool box A5, the tool box limiting jig 83 is pushed to one side of the front foot ladder limiting jig 6 which has completed the vertical drilling process, and the tool box A5 is inserted into the top of the two eight-shaped arranged ladder pipes A1, the tool box A5 is fixed on the top of the ladder pipes A1 by the fastener on the drilling device, and the installation of the tool box A5 is completed.

[0116] In the preferred embodiment, the tool box mounting mechanism 8 includes a tool box feeding device 81 for feeding the tool box A5, a third robot 82 for grabbing the tool box A5, a tool box positioning jig 83 for fixing the position of the tool box A5, a tool box clamping hand 84 for clamping the tool box A5 on the tool box positioning jig 83, a tool box pushing device 85 for pushing the tool box A5 to the top of the two ladders A1, a tool box drilling device 86 for locking the tool box A5 on the two ladders A1. If the direction of the tool box A5 needs to be adjusted, the tool box mounting mechanism 8 further includes a rotating tool 87 for adjusting the direction of the tool box A5. The third robot 82 is driven by power driving part four to move along the X-axis and Z-axis directions, so that it transfers the feeding device or the rotating tool 87 to the tool box positioning jig 83, and fixes it on the tool box positioning jig 83 by the tool box clamping hand 84; the tool box pushing device 85 is driven by power driving part five 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 fed along the Y-axis direction until it is inserted into the top of the two ladders A1, in order to further fix the position of the tool box A5, the tool box drilling device 86 is located at the top of the ladders A1 and the tool box A5, the tool box drilling device 86 rotates downward along the Z-axis direction, and the tool box A5 is locked on the two ladders A1 by fasteners, completing the installation of the tool box A5.

[0117] As a further preferred scheme, a crossbar pre-assembly step is further included before feeding: in the crossbar pre-assembly step, the two ends of the crossbar A2 are provided with recessed connectors A21 for quick assembly, and the recessed connectors are fixed at the two ends of the crossbar A2 by a crossbar pre-assembly mechanism 9.

[0118] The crossbar pre-assembly mechanism 9 includes a crossbar positioning jig 91 for fixing the crossbar A2, a crossbar pressing device 92 for pressing the crossbar A2, a connector feeding device 93 for feeding the recessed connectors A21, a connector positioning seat 94 for defining the position of the recessed connectors A21, an anti-displacement device 95 for preventing the recessed connectors A21 from slipping off, and a connector pushing device 96 for pushing and fixing the recessed connectors A21 at the two ends of the crossbar. First, the crossbar A2 is pressed and fixed on the crossbar positioning jig 91, the connector feeding device 93 feeds the recessed connectors A21 to the connector positioning seat 94 through a feeding groove, and then the connector pushing device 96 pushes and fixes the recessed connectors A21 at the two ends of the crossbar A2, completing the pre-assembly process of the crossbar A2.

[0119] As a further preferred solution, the step of preloading the top pedal pipe penetrating and dotting is further included before loading: in the step of preloading the top pedal pipe penetrating and dotting, the top pedal A4 is provided with a pivot pipe for pivoting between the two ladder pipes A1, the pivot pipe is penetrated on the top pedal A4 by the top pedal pipe penetrating and dotting mechanism 10, and is rotatably limited and installed on the top pedal A4.

[0120] The top pedal pipe penetrating and dotting mechanism 10 includes a pedal limiting jig 101, a material guiding groove 102, a rotating frame 103, a penetrating device 104, and a pressing 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 mounting the pivot pipe; the material guiding groove 102 is provided with a material discharge port for the pivot pipe to pass through and a material guiding slope for providing gravity power for the material discharge port; the rotating frame 103 is arranged on one side of the material discharge port, and is used for rotating and conveying the pivot pipe of the material discharge port to a preset height of the mounting hole; the penetrating device 104 penetrates the pivot pipe on the rotating frame 103 into the mounting hole of the top pedal A4 from the horizontal direction, and leaves the same length of pipe opening on both sides of the top pedal A4; and the pressing limiting device is pressed in the vertical direction to the pipe opening on both sides of the top pedal A4, so as to deform the pipe opening and limit the activity range of the top pedal A4 on the pivot pipe.

[0121] The above-mentioned embodiments are only preferred embodiments of the present application, and cannot be used to limit the protection scope of the present application. Any non-essential changes and replacements made by those skilled in the art on the basis of the present application shall fall within the protection scope of the present application.

Claims

1. A method of assembling a metal A-frame ladder front step ladder, characterized by, The metal ladder front ladder foot ladder assembly device is used for assembling, and specifically comprises the following steps: Feeding: the ladder pipe is horizontally transferred to the front of the horizontal drilling station through the ladder pipe feeding mechanism, and then the ladder pipe at the end of the conveying is turned from the horizontal state to the upright state; Horizontal drilling: the first mechanical hand clamps the ladder pipe in the upright state, horizontally transfers it to the ladder pipe limiting seat, clamps and fixes its position, and drills and / or punches the inner side of the ladder pipe through the horizontal drilling mechanism; Foot sleeve installation and extrusion positioning: after the horizontal drilling is completed, the foot sleeve is pushed into the end of the ladder pipe through the foot sleeve installation mechanism, and then the extrusion deformation mechanism is used to extrude the preset position of the ladder pipe to locally recess and deform the ladder pipe, so that the foot sleeve is fixed and positioned at the end of the ladder pipe; The foot sleeve installation mechanism comprises a magazine slot for conveying the foot sleeve, 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 and top assembly for pushing the foot sleeve out of the magazine slot and into the bottom end of the ladder pipe; the magazine slot is provided with at least one discharge port and a feeding port; The extrusion deformation mechanism comprises an extrusion block, an extrusion block Z-axis extension and retraction device for driving the extrusion block to extend and retract along the Z-axis direction, and an extrusion block Y-axis sliding device for driving the extrusion block Z-axis extension and retraction device to move left and right along the Y-axis direction; the extrusion block is located above the foot sleeve installation mechanism; The foot sleeve enters the magazine slot from the feeding port, is pushed to the discharge port by the reciprocating pusher, and when it is detected that the ladder pipe is in place at the discharge port, the pushing and top assembly is extended to push the foot sleeve out of the magazine slot and 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 the preset position above the ladder pipe by the extrusion block shaft sliding device, and then the extrusion block Z-axis extension and retraction device drives it to extrude downward, so that the ladder pipe locally recesses and deforms at the preset position to fix and position the foot sleeve at the bottom end of the ladder pipe; Front foot ladder accessory shaping: the second mechanical hand clamps and tilts the two ladder pipes after the foot sleeve is installed, and places them in the eight-shaped position on the front foot ladder limiting jig preset position; the horizontal rod and the top step are placed between the two ladder pipes according to the preset position of the front foot ladder limiting jig; the frame installation of the front foot ladder is completed; The front foot ladder limiting jig comprises a bottom plate, a first ladder pipe limiting seat, a second ladder pipe limiting seat, a horizontal rod limiting seat, a foot sleeve positioning seat, a step limiting seat and a lock buckle; the first ladder pipe limiting seat and the second ladder pipe limiting seat are arranged in an eight-shaped manner on the bottom plate, and the horizontal rod limiting seat and the step limiting seat are arranged between the first ladder pipe limiting seat and the second ladder pipe limiting seat; the first ladder pipe limiting seat is fixedly installed on the bottom plate, and the second ladder pipe limiting seat is movably installed on the bottom plate between the position close to or away from the first ladder pipe limiting seat; the end of the first ladder pipe limiting seat and the second ladder pipe limiting seat is provided with a foot sleeve positioning seat for limiting the starting position of the foot sleeve at the bottom of the front foot ladder. After the installation of the foot cover, the second mechanical hand mechanism automatically installs the ladder pipe on the first ladder pipe limiting seat and the second ladder pipe limiting seat, and the ladder pipe is distributed in the shape of a split, then the crossbar and the top pedal are installed between the two ladder pipes, and finally the second ladder pipe limiting seat is slid close to the first ladder pipe limiting seat, and the position of the second ladder pipe limiting seat is fixed by the lock buckle, so that the front ladder is completely installed according to the preset angle and position and is limited on the front ladder limiting jig; The vertical drilling and tapping: the Y-axis conveying device transfers the whole front ladder limiting jig to the vertical drilling and tapping station, and the crossbar and the top pedal are locked on the ladder pipe by the vertical drilling and tapping device, so that the frame of the front ladder is fixed as a whole.

2. The method of assembling a metal A-frame ladder of claim 1, wherein, In the step of loading, the ladder pipe loading mechanism includes an X-axis conveying device for horizontally conveying the ladder pipe, a turning device for turning the ladder pipe by 90° horizontally, and a first mechanical hand mechanism for transferring the ladder pipe from the loading station to the drilling station; the turning 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, the turning device is rotated to make the short side of the cross section of the ladder pipe face upward; and the first mechanical hand mechanism transfers the ladder pipe from the loading station to the drilling station.

3. The method of assembling a metal A-frame ladder of claim 1, wherein, In the step of horizontal drilling, the horizontal drilling mechanism includes a ladder pipe limiting seat, a horizontal drilling and tapping device, a horizontal punching device, and a pressing assembly; the horizontal drilling and tapping device and the horizontal punching device are located on one side of the ladder pipe limiting seat, and the pressing assembly is arranged on the other side of the ladder pipe limiting seat; when the horizontal drilling mechanism detects that the ladder pipe is placed on the ladder pipe limiting seat, the pressing assembly presses the ladder pipe in the ladder pipe limiting seat, and the horizontal drilling and tapping device and the horizontal punching device drill and tap or punch at the preset drilling position of the ladder pipe.

4. The method of claim 1, wherein: In the step of vertical drilling and tapping, the Y-axis conveying device transfers the whole front ladder limiting jig to the vertical drilling and tapping station; at this time, the ladder pipes on the front ladder limiting jig are distributed in the shape of a split, and the crossbar and the top pedal are locked on the ladder pipe by the vertical drilling and tapping device, so that the frame of the front ladder is fixed as a whole.

5. The method of assembling a metal step ladder front ladder of claim 1, wherein, After the vertical drilling and tapping, the step of tool box installation is further included. In the step of tool box installation, the tool box is clamped and transferred to the preset tool box limiting jig by the tool box installation mechanism; the left and right pushing mechanisms of 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 which has completed the vertical drilling and tapping process, and the tool box is inserted into the top of the two ladder pipes arranged in the shape of a split; the tool box is fixed on the top of the ladder pipe by the fastener on the drilling and tapping device, and the installation of the tool box is completed.

6. The method of assembling a metal step ladder front ladder of claim 5, wherein, The tool box installation mechanism includes a tool box loading device for conveying the tool box, a third mechanical hand for grabbing the tool box, a tool box limiting jig for fixing the position of the tool box, a tool box clamping hand for clamping the tool box on the tool box limiting jig, 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 it is necessary to adjust the direction of the tool box, the tool box installation mechanism further includes a rotating tool for adjusting the direction of the tool box. The third mechanical arm is driven by a power driving element to move along the X-axis and Z-axis directions, so as to transfer the feeding device or the rotating tool to the tool box limiting jig, and is fixed on the tool box limiting jig by the tool box clamping hand; the tool box pushing device is driven by a power driving element to move along the Y-axis and Z-axis directions, at this time, the height direction of the Z-axis is adjusted by the tool box pushing device, and then the tool box is transported along the Y-axis direction until it is inserted into the top of the two ladder pipes; the tool box drilling and tapping device is located at the top of the ladder pipe and the tool box, and is rotated downward along the Z-axis direction, so as to lock the tool box on the two ladder pipes by the fastener, and the installation of the tool box is completed.

7. The method of assembling a metal step ladder front ladder of claim 1, wherein, Before feeding, a cross rod preloading step is further included: in the cross rod preloading step, the two ends of the cross rod are provided with female connectors for quick installation, and the female connectors are fixed at the two ends of the cross rod by a cross rod preloading mechanism; The cross rod preloading mechanism includes a cross rod limiting jig for fixing the cross rod, a cross rod pressing device for pressing the cross rod, a connector feeding device for feeding the female connectors, a connector limiting seat for limiting the position of the female connectors, an anti-disengagement device for preventing the female connectors from slipping off, and a connector pushing device for pushing and fixing the female connectors at the two ends of the cross rod; First, the cross rod is pressed and fixed on the cross rod limiting jig, the connector feeding device feeds the female connectors to the connector limiting seat through a feeding groove, and then the connector pushing device pushes and fixes the female connectors at the two ends of the cross rod, thereby completing the preloading process of the cross rod.

8. The method of assembling a metal step ladder front ladder of claim 1, wherein, Before feeding, a top pedal pipe penetrating and dotting preloading step is further included: in the top pedal pipe penetrating and dotting preloading step, the top pedal is provided with a pivot pipe for pivoting between the two ladder pipes, the pivot pipe is penetrated on the top pedal by a top pedal pipe penetrating and dotting mechanism, and is rotatably limited and installed on the top pedal; The top pedal pipe penetrating and dotting mechanism includes a pedal limiting jig, a material guide groove, a rotating frame, a penetrating device, and a downward limiting device; the top pedal is limited on the pedal limiting jig, and the top pedal is provided with a mounting hole for mounting the pivot pipe; the material guide groove is provided with a material discharge port through which the pivot pipe passes, and a material guide inclined surface for providing gravity power for the material discharge port; the rotating frame is arranged on one side of the material discharge port, and is used for rotating and feeding the pivot pipe of the material discharge port to a preset height of the mounting hole; the penetrating device penetrates the pivot pipe on the rotating frame into the mounting hole of the top pedal from the horizontal direction, and leaves pipe openings with the same length on both sides of the top pedal; the downward limiting device is pressed downward in the vertical direction to the pipe openings on both sides of the top pedal, so as to deform the pipe openings and limit the movement range of the top pedal on the pivot pipe.

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