Pipe raw material flexible selecting and storing warehouse and automatic storing and taking method thereof

Abstract

The application discloses a kind of pipe fittings raw material flexible selection material vertical warehouse and automatic access method thereof, it is related to warehousing equipment field.It includes storage rack and transfer truss, and storage rack is equipped with multiple layers of storage space and drawer type pipe fittings storage rack;Transfer truss integrates lifting, horizontal push-pull and grabbing mechanism.The core is that horizontal push-pull mechanism is equipped with reciprocating pressing locking assembly, utilizes spring and continuous guide wheel profile cooperation, so that guide rod is pressed and rotates and is mismatched with material tray clamping groove and is locked, realizes pure mechanical self-locking pull and secondary pressing unlocking.The application avoids pipe fittings knock by stereoscopic storage, is exempted from additional power source by pure mechanical self-locking, is combined with digital identification, realizes the high-density storage of pipe fittings and unmanned flexible access.

Description

Technical Field

[0001] This invention relates to the field of warehousing equipment technology, and in particular to a flexible material selection vertical warehouse for pipe fitting raw materials and its automatic storage and retrieval method. Background Technology

[0002] In pipe manufacturing, material preparation, and welding workshops, the storage and handling of raw materials for pipe fittings are crucial aspects of the production process. Currently, most pipe fitting materials in the industry are stored by stacking or laying them flat on the ground. This method has the following significant drawbacks: Firstly, flat stacking occupies a large area and has extremely low space utilization. Moreover, the pipes are in direct contact with each other, making them prone to collisions and scratches during hoisting or stacking, which seriously affects the surface quality of raw materials and subsequent welding processes. Secondly, material management relies on manual labor, the pipe fittings are coded in no order, and each storage and retrieval requires on-site manual measurement, registration and filing, resulting in a lack of synchronization between accounts and physical inventory and a lag in information flow. Third, material handling operations mostly rely on traditional gantry cranes or forklifts, requiring manual hooking, command, and operation, which is labor-intensive, has high safety risks, and cannot be integrated with the workshop's MES / WMS system, making it difficult to achieve unmanned and flexible production.

[0003] Therefore, there is an urgent need for a pipe fitting raw material storage equipment that can make full use of three-dimensional space, avoid material collisions, and has fully automatic and accurate storage and retrieval capabilities. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide a flexible material selection vertical warehouse for pipe fitting raw materials and its automatic storage and retrieval method.

[0005] To solve the above technical problems, the technical solution of the present invention is as follows: On one hand, the present invention provides a flexible material selection vertical storage for pipe fitting raw materials, comprising: a storage rack, including a supporting frame and a plurality of pipe fitting storage racks, wherein the supporting frame has a plurality of storage spaces stacked in a vertical direction, and the pipe fitting storage racks are retractable and disposed in the storage spaces; a transfer truss, disposed on one side of the supporting frame, the transfer truss comprising a truss body, a lifting drive mechanism disposed on the truss body, a horizontal push-pull mechanism driven by the lifting drive mechanism, and a pipe fitting gripping mechanism disposed on the truss body; The horizontal push-pull mechanism is used to connect with the pipe storage rack to horizontally pull the pipe storage rack out of the support frame from the storage space; the pipe gripping mechanism is used to grip or place the pipes on the pipe storage rack after the pipe storage rack is pulled out of the support frame.

[0006] The above solution transforms traditional planar stacking into high-density three-dimensional storage by combining vertically stacked storage space within the supporting frame with pull-out pipe storage racks, reducing the floor space by more than 60%. The drawer-type independent material position design completely isolates the physical contact between pipes, eliminating bumps and scratches during hoisting and stacking, and ensuring the surface quality of raw materials.

[0007] On the other hand, the present invention provides an automatic storage and retrieval method for a flexible material selection vertical warehouse for pipe fitting raw materials, comprising the following steps: Receive material extraction instructions based on production needs, parse the material extraction instructions and retrieve the target pipe position coordinate information bound by the position identifier in the data terminal, control the lifting drive mechanism to operate according to the position coordinate information, and drive the horizontal push-pull mechanism to move vertically to the alignment coordinate position with the layer where the target pipe storage rack is located; Control the horizontal push-pull mechanism to move forward and engage with and lock with the material tray slot of the pipe fitting storage rack; after locking, the horizontal push-pull mechanism moves backward horizontally to pull the pipe fitting storage rack out of the support frame; The control pipe gripping mechanism moves to the coordinate position directly above the target pipe, descends and grips the target pipe, and then transports and places it on the discharge rack; The horizontal push-pull mechanism pushes in the opposite direction, pushing the pipe storage rack back into the receiving space of the supporting frame. When it is pushed into the limit coordinate position, it is pressed to trigger the unlocking action. The horizontal push-pull mechanism retracts and separates after the locking end is completely disengaged from the material tray slot.

[0008] The beneficial effects of this invention are: (1) In this invention, the transfer truss integrates Z-axis lifting drive, X / Y-axis horizontal push-pull and multi-degree-of-freedom pipe gripping mechanism, replacing the traditional manual crane. The horizontal push-pull mechanism is responsible for the overall outbound / inbound of the drawer, and the pipe gripping mechanism is responsible for the precise addressing and flexible gripping of a single pipe. The action sequence is decoupled and does not interfere with each other, increasing the storage and retrieval cycle by more than 3 times, and completely eliminating the safety hazards of manual high-altitude operations.

[0009] (2) In this invention, the front end of the horizontal push-pull mechanism adopts a reciprocating press-lock assembly. By utilizing the return spring, the radial protrusion and the cam trajectory of the continuous guide contour, a purely mechanical self-locking logic of "one press to rotate and lock, two presses to rotate and unlock" is achieved. This structure does not require additional locking cylinders, electromagnets or position sensors. It has an extremely low failure rate under harsh working conditions such as dust, oil, and vibration in the workshop, greatly simplifying the PLC control logic. At the same time, the spring preload ensures that the rigid connection does not disengage during the heavy-load pull-out process.

[0010] (3) This invention uses evenly distributed position markings on independent material locations on the storage rack and introduces marking resolution and coordinate retrieval logic into the control steps. This solution solves the problem that traditional automated storage and retrieval systems can only perform "whole-pan scheduling". The physical material locations and the information-level data terminals are bound one-to-one, and the system can accurately obtain the absolute three-dimensional X / Y / Z coordinates of each pipe fitting with different diameters and materials. Even with a wide variety of pipe fittings, the robotic arm can achieve millimeter-level precision "blind picking", truly realizing flexible on-demand material distribution of loose pipe fittings. Attached Figure Description

[0011] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 A schematic diagram of the flexible material selection vertical storage silo for pipe fitting raw materials provided by the present invention; Figure 2 A schematic diagram of the storage rack in the flexible material selection vertical warehouse for pipe fitting raw materials provided by the present invention; Figure 3 A schematic diagram of the transfer truss in the flexible material selection vertical warehouse for pipe fitting raw materials provided by the present invention; Figure 4 A schematic diagram of the reciprocating pressing and locking assembly in the flexible material selection vertical warehouse for pipe fitting raw materials provided by the present invention; Figure 5 A schematic diagram of the pipe fitting clamp in the flexible material selection vertical warehouse for pipe fitting raw materials provided by the present invention; Wherein: 100, storage rack; 200, transfer truss; 110, load-bearing frame; 120, pipe fitting storage rack; 130, storage space; 121, material tray slot; 121-1, opening; 121-2, locking slot; 210, truss body; 220, lifting drive mechanism; 230, horizontal push-pull mechanism; 240, pipe fitting gripping mechanism; 250, lifting platform; 231, rotating slot; 232, rotating push-pull guide rod; 233, return spring; 232-1, radial extension; 231-1, continuous guide profile; 234, servo motor; 235, first guide member; 236, crossbeam; 237, second guide member; 238, lifting drive assembly; 239, pipe fitting clamp. Detailed Implementation

[0013] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings.

[0014] Example 1: See Figures 1-5 This embodiment provides a flexible material selection vertical storage system for pipe fitting raw materials, which consists of two core parts: a static storage end (storage rack 100) and a dynamic execution end (transfer truss 200). The specific structure is as follows: The storage rack 100 includes a support frame 110 and several pipe fitting storage racks 120. The support frame 110 is specifically a multi-layer, three-dimensional shelving structure welded / bolted from rectangular steel pipes or H-beams, with several vertically equidistant storage spaces 130 inside. Each storage space 130 has heavy-duty linear guides or V-shaped roller grooves (i.e., sliding guide structures) fixedly installed on both sides of its bottom. The pipe fitting storage racks 120 are drawer-type steel trays with sliders or load-bearing rollers at the bottom that cooperate with the guides / roller grooves, allowing the trays to be smoothly pulled out horizontally. Several V-shaped or U-shaped support blocks are welded inside the trays according to the length of the pipe fittings, forming parallel storage positions to prevent the pipe fittings from rolling.

[0015] It should be noted that each material location is equipped with an independent location identifier, which is used to bind the material information of the pipe fittings placed at that location with the location coordinate information.

[0016] In this embodiment, the location identifier is specifically an anti-metal RFID electronic tag or an industrial-grade QR code nameplate, riveted to the frame beam 236 of each material location on each layer. An RFID reader or industrial camera is installed on the transfer truss 200. The data terminal is specifically a workshop industrial control computer or PLC, with a built-in WCS warehouse control system responsible for parsing coordinates, scheduling the three-axis linkage of the truss, and recording inventory status. By reading the location identifier, the system maps the length, diameter, material, and batch information of each pipe fitting to its absolute mechanical coordinates in the automated warehouse system and stores this mapping in the database, forming a digital twin model.

[0017] The transfer truss 200 is installed on the material inlet / outlet side of the load-bearing frame 110. The truss body 210 is specifically a gantry-type double-column steel structure. The bottom of the columns is fixed to the workshop floor with anchor bolts and adjustable shims are provided to ensure verticality. The lifting drive mechanism 220, the horizontal push-pull mechanism 230, and the pipe gripping mechanism 240 are all integrated on the truss body 210, forming an XYZ three-axis rectangular coordinate motion system.

[0018] Specifically, the lifting drive mechanism 220 uses a servo motor 234 in conjunction with a precision ball screw pair, or a servo motor 234 in conjunction with a double-row chain / synchronous belt drive mechanism. The output end of the mechanism is connected to a lifting platform 250, which has guide rollers at its four corners and slides along the vertical guide rails on the inner side of the truss column.

[0019] In this embodiment, the lifting drive mechanism 220 may specifically be a traction wire rope winch, a sprocket and chain hoist, or a high-power servo motor 234 with a ball screw mechanism.

[0020] A horizontal push-pull mechanism 230 is mounted on a lifting platform 250. This mechanism includes a horizontal drive assembly and a reciprocating pressing and locking assembly. The horizontal push-pull mechanism 230 employs a transmission system consisting of a servo motor 234, a planetary reducer, a drive gear, and a precision rack. The rack is fixedly laid horizontally on the platform surface of the lifting platform 250. A push-pull guide rail extending along the length of the platform is provided on the platform surface of the lifting platform 250, and a push-pull movable seat is slidably mounted on this guide rail. The servo motor 234 and the planetary reducer are fixedly mounted on this push-pull movable seat, and the drive gear meshes with the rack, converting rotary motion into linear reciprocating motion, thereby driving the push-pull movable seat to reciprocate along the push-pull guide rail.

[0021] The reciprocating push-lock assembly includes a rotating slot 231, a rotating push-pull guide rod 232, and a return spring 233. The rotating slot 231 is fixedly mounted on the aforementioned push-pull movable base and is a guide sleeve structure, with its end machined into a continuous guide profile 231-1 (see [reference]). Figure 4 The profile is specifically a heart-shaped cam groove or a spiral guide groove, with the groove depth varying circumferentially to form an alternating connection trajectory of guide slope, locking retaining groove, and unlocking return groove. The rotary push-pull guide rod 232 is coaxially inserted into the guide sleeve, and its sidewall is press-fitted or threaded with a radial protrusion that is always embedded and slides within the continuous guide profile 231-1. A locking end is fixed to the front end of the rotary push-pull guide rod 232, specifically a butt joint with a radial extension 232-1 (such as a T-head, cam block, or irregular hook). A return spring 233 is sleeved on the middle section of the outer side of the rotary push-pull guide rod 232, with both ends of the return spring 233 abutting against the inner stepped surface of the rotary slot 231 and the shoulder stepped surface of the guide rod, respectively, providing axial return force and self-locking preload.

[0022] In conjunction with the aforementioned reciprocating press-lock assembly, a tray slot 121 is fixedly installed on each pipe storage rack 120. This tray slot 121 is a metal mating seat fixed to the side panel of the pipe storage rack 120 facing the transfer truss 200, and its interior has a cross-shaped or T-shaped through slot. Specifically, the tray slot 121 includes an opening 121-1 for the locking end of the rotating push-pull guide rod 232 to be inserted linearly, and a locking groove 121-2 located behind the opening 121-1 and offset 90° circumferentially. The inner wall of the locking groove 121-2 has a stop surface to withstand axial tensile force.

[0023] The pipe gripping mechanism 240 is mounted on top of the truss body 210. The top of the truss body 210 is a guide bracket fixedly installed on the upper end of the truss column. This guide bracket includes a first guide member 235 arranged along a first horizontal direction and a crossbeam 236 slidably mounted on the first guide member 235 and extending along a second horizontal direction. The first horizontal direction is typically the X-axis, i.e., the length direction of the vertical storage unit. The first guide member 235 is specifically two parallel heavy-duty linear sliding guide rails fixed to the top of the truss column. The second horizontal direction is typically the Y-axis, the width direction of the vertical storage unit. The crossbeam 236, which laterally spans the two first guide members 235, is such as an aluminum profile heavy-duty truss beam, and its side or top surface is equipped with a second guide member 237, also a linear guide rail. The pipe gripping mechanism 240 specifically includes a translation seat slidably mounted on the crossbeam 236 via the second guide 237, a first drive assembly for driving the crossbeam 236 to translate along the first guide 235, a second drive assembly for driving the translation seat to translate along the second guide 237, a lifting drive assembly 238 fixedly mounted on the translation seat, and a pipe clamp 239 drivenly connected to the lifting drive assembly 238.

[0024] In this embodiment, the first drive assembly and the second drive assembly can specifically employ an AC servo motor 234 driving a synchronous belt pulley mechanism or a servo motor 234 driving a gear and rack mechanism. The lifting drive assembly 238 can specifically employ a pneumatic rodless cylinder, an electric push rod, or a motor-driven lead screw slide module.

[0025] Example 2: This example provides an automatic storage and retrieval method for a flexible material selection vertical storage warehouse for pipe fitting raw materials. The method specifically includes the following steps: Step S1: Initial docking.

[0026] Specifically, the system receives material extraction instructions based on production needs, parses the material extraction instructions, retrieves the target pipe location coordinate information bound by the location identifier in the data terminal, controls the lifting drive mechanism 220 to run according to the location coordinate information, and drives the horizontal push-pull mechanism 230 to move vertically to the alignment coordinate position at the same height as the layer where the target pipe storage rack 120 is located.

[0027] Step S2: Mechanical locking (one press) and drawer pull-out.

[0028] Specifically, the horizontal drive assembly drives the reciprocating push-lock assembly to extend forward. When the locking end is inserted into the opening 121-1 of the tray slot 121 and touches the bottom stop, the axial resistance forces the rotary push-pull guide to retract relative to the rotary slot 231, and the return spring 233 is compressed. At this time, the radial protrusion is subjected to the lateral component force of the guide slope in the continuous guide contour 231-1, which drives the guide rod and the locking end to rotate synchronously by 90°. When the horizontal push-pull mechanism 230 stops moving forward (axial pressure is released), the return spring 233 releases its elastic force, pushing the radial protrusion into the locking retaining groove and locking it in place. At this time, the radial extension 232-1 of the locking end rotates to a state of misalignment and overlap with the locking groove 121-2, forming a rigid axial locking connection. After locking, the horizontal push-pull mechanism 230 moves horizontally backward, pulling the pipe storage rack 120 out of the support frame 110.

[0029] Step S3: Flexible grasping.

[0030] Specifically, the first and second drive components of the pipe gripping mechanism 240 work together to move the translation seat directly above the target pipe, the lifting drive component 238 descends, the pipe clamp 239 closes to grip the pipe, and after lifting, it is translated to the top of the discharge rack for release. This process can achieve precise sorting of single or multiple pipes.

[0031] Step S4: Push the drawer back and unlock it mechanically (press twice).

[0032] Specifically, after the gripping is complete, the horizontal drive assembly moves forward, pushing the pipe storage rack 120 back into the storage space 130. When the tray is pushed to its limit position (fully inserted), the locking end is subjected to axial compression again. The radial protrusion is pushed out of the locking retaining groove and continues to slide along the next guide ramp, forcing the guide rod to rotate 90° again. Then the protrusion enters the unlocking return groove, at which point the radial extension 232-1 of the locking end is aligned again with the opening 121-1. Under the continuous thrust of the return spring 233, the rotating push-pull guide rod 232 automatically pops forward, and the locking end completely disengages from the tray slot 121, achieving automatic unhooking without power. The horizontal push-pull mechanism 230 retracts and resets, ready for the next operation.

[0033] It should be noted that throughout the entire storage and retrieval process, the location identifier is read in real time, and the data terminal synchronously updates the "occupied / idle" status of the material location and the material batch information. If the production plan changes, the system can dynamically adjust the grabbing sequence, achieving truly flexible material selection and unmanned warehousing.

[0034] In addition to the above embodiments, the present invention may have other implementation methods; all technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.

Claims

1. A flexible material selection vertical storage silo for pipe fitting raw materials, characterized in that, include: The storage rack (100) includes a support frame (110) and a plurality of pipe storage racks (120). The support frame (110) has a plurality of storage spaces (130) stacked in a vertical direction. The pipe storage racks (120) are removably disposed in the storage spaces (130). A transfer truss (200) is disposed on one side of the bearing frame (110). The transfer truss (200) includes a truss body (210), a lifting drive mechanism (220) disposed on the truss body (210), a horizontal push-pull mechanism (230) driven by the lifting drive mechanism (220), and a pipe gripping mechanism (240) disposed on the truss body (210). The horizontal push-pull mechanism (230) is used to connect with the pipe storage rack (120) to horizontally pull the pipe storage rack (120) out of the support frame (110) from the storage space (130); the pipe gripping mechanism (240) is used to grip or place the pipes on the pipe storage rack (120) after the pipe storage rack (120) is pulled out of the support frame (110).

2. The flexible material selection vertical silo for pipe fitting raw materials according to claim 1, characterized in that, The horizontal push-pull mechanism (230) has a locking end at its front end. The pipe storage rack (120) has a material tray slot (121) fixedly provided on the side facing the transfer truss (200). The material tray slot (121) includes an opening (121-1) into which the locking end extends and a locking groove (121-2) that communicates with the opening (121-1) and is circumferentially offset. Wherein, after the locking end extends into the opening (121-1), it can be rotated at a set angle and locked into the locking groove (121-2) so that the locking end and the tray groove (121) form an axial locking connection.

3. The flexible material selection vertical silo for pipe fitting raw materials according to claim 2, characterized in that, The horizontal push-pull mechanism (230) includes a reciprocating press-lock assembly and a horizontal drive assembly for driving the reciprocating press-lock assembly to reciprocate in the horizontal direction; The reciprocating press-lock assembly includes a rotating slot (231), a rotating push-pull guide rod (232), and a return spring (233). The locking end is fixedly disposed at one end of the rotating push-pull guide rod (232), and the locking end is provided with a radial extension (232-1). A radial protrusion is fixedly disposed on the side wall of the rotating push-pull guide rod (232). A continuous guide profile (231-1) extending circumferentially along the rotating slot (231) is provided on the mating surface of the rotating slot (231) that mates with the radial protrusion. The guide profile (231-1) includes a guide ramp and a locking retaining groove and an unlocking return groove that are alternately connected by the guide ramp; the rotating push-pull guide rod (232) is coaxially inserted through the rotating slot (231), and the radial protrusion slides against the continuous guide profile (231-1); the return spring (233) is sleeved on the outside of the rotating push-pull guide rod (232), and the two ends of the return spring (233) respectively abut against the fixed surface of the rotating slot (231) and the force-bearing step surface of the rotating push-pull guide rod (232).

4. The flexible material selection vertical silo for pipe fitting raw materials according to claim 3, characterized in that, The rotary push-pull guide rod (232) is configured as follows: When the locking end abuts against the tray groove (121) and is subjected to axial pressure, the rotating push-pull guide rod (232) moves axially away from the tray groove (121) relative to the rotating groove (231) and compresses the return spring (233), and the radial protrusion slides along the guide slope, so that the rotating push-pull guide rod (232) rotates circumferentially at a set angle; When the axial pressure is removed, the radial protrusion falls into the locking groove under the elastic force of the return spring (233) to form a self-locking mechanism, causing the radial extension (232-1) of the locking end to be misaligned and inserted into the locking groove (121-2) to form a locking connection. When subjected to axial pressure again, the radial protrusion is pushed out of the locking retaining groove and slides along the adjacent next guide slope, forcing the rotary push-pull guide rod (232) to rotate again by a set angle, so that the radial protrusion enters the unlocking return groove, and the radial extension (232-1) of the locking end is circumferentially aligned with the opening (121-1). Under the reset thrust of the reset spring (233), the rotary push-pull guide rod (232) axially disengages from the tray slot (121) to form unlocking separation.

5. The flexible material selection vertical silo for pipe fitting raw materials according to claim 3, characterized in that, The lifting drive mechanism (220) is driven to connect with the lifting platform (250), and the horizontal push-pull mechanism (230) is disposed on the lifting platform (250); The horizontal drive assembly includes a servo motor (234), a reducer connected to the servo motor (234), a drive gear installed at the output end of the reducer, and a rack laid along the moving direction of the horizontal push-pull mechanism (230). The rack is fixedly installed on the lifting platform (250), and the drive gear meshes with the rack.

6. The flexible material selection vertical silo for pipe fitting raw materials according to claim 1, characterized in that, The truss body (210) includes two sets of truss columns arranged opposite to each other and a guide bracket fixedly installed on the upper end of the truss columns. The guide bracket includes a first guide member (235) arranged along a first horizontal direction and a crossbeam (236) slidably mounted on the first guide member (235) and extending along a second horizontal direction. The first horizontal direction and the second horizontal direction are perpendicular to each other. A second guide member (237) arranged along the second horizontal direction is provided on the crossbeam (236). The pipe gripping mechanism (240) includes a translation seat slidably mounted on the crossbeam (236) via the second guide (237), a first drive assembly for driving the crossbeam (236) to translate along the first guide (235), a second drive assembly for driving the translation seat to translate along the second guide (237), a lifting drive assembly (238) fixedly mounted on the translation seat, and a pipe clamp (239) drivenly connected to the lifting drive assembly (238).

7. The flexible material selection vertical silo for pipe fitting raw materials according to claim 1, characterized in that, The pipe storage rack (120) has several material positions for carrying pipes arranged side by side, and each material position is provided with a position mark. The position mark is used to bind the material information of the pipe placed in the material position with the position coordinate information.

8. An automatic storage and retrieval method for a flexible material selection vertical storage silo for pipe fitting raw materials, applied to the flexible material selection vertical storage silo for pipe fitting raw materials as described in any one of claims 1 to 7, characterized in that, Includes the following steps: Receive material extraction instructions based on production needs, parse the instructions and retrieve the target pipe position coordinate information bound by the position identifier in the data terminal, control the lifting drive mechanism (220) to run according to the position coordinate information, and drive the horizontal push-pull mechanism (230) to move vertically to the alignment coordinate position with the layer where the target pipe storage rack (120) is located; The horizontal push-pull mechanism (230) is controlled to move forward and engage with and lock with the tray slot (121) of the pipe fitting storage rack (120); after locking, the horizontal push-pull mechanism (230) moves backward horizontally and pulls the pipe fitting storage rack (120) out of the support frame (110); Control the pipe gripping mechanism (240) to run to the coordinate position directly above the target pipe, descend and grip the target pipe, and then transport and place it to the discharge rack; The horizontal push-pull mechanism (230) pushes in the opposite direction, pushing the pipe storage rack (120) back into the accommodating space of the bearing frame (110), and triggers the unlocking action when pushed into the limit coordinate position. The horizontal push-pull mechanism (230) then retracts and separates after the locking end is completely disengaged from the material tray slot (121).

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