Self-locking carton with flexible liner corrugated board

Abstract

This utility model discloses a self-locking cardboard box using flexible corrugated cardboard, comprising an integral cardboard unfolding sheet and a locking plate with identical layer structures. The integral cardboard unfolding sheet has several self-retaining grooves along the folding path required for box forming, serving as fold lines. The integral cardboard unfolding sheet has self-locking structures on opposite sides. After folding along the grooves, the integral cardboard unfolding sheet forms a cardboard box frame including a front panel, a back panel, and two side panels. The locking plate is spliced ​​and combined with the top and bottom of the cardboard box frame through the self-locking structures to form a complete box body. The integral cardboard unfolding sheet is composed of an outer liner layer, corrugated core paper, and an inner liner layer that combines flexibility and moisture resistance. Recycled paper fiber flakes are filled into the flutes of the corrugated core paper as a soft protective layer. The recycled paper fiber flakes are continuously distributed along the board surface and are jointly limited and fixed by the inner and outer liner layers in the thickness direction. This improves the packaging's resistance to drops and compression of the contents without adding additional inner liner material.

Description

Technical Field

[0001] This utility model relates to the field of packaging, specifically to a self-locking cardboard box using flexible corrugated cardboard. Background Technology

[0002] In high-frequency distribution sectors such as e-commerce, daily chemicals, and small appliances, cardboard packaging often needs to pass drop and stacking tests to ensure logistics safety, thus relying heavily on heterogeneous cushioning linings such as foam, honeycomb cardboard, or inflatable bags. While these auxiliary materials can provide some protection, they increase packaging costs, packing time, and transportation weight, reduce effective volume, and require sorting after unpacking, making single-material recycling difficult, which runs counter to the trend of "reduced and recyclable" green packaging. Traditional corrugated cardboard often uses relatively stiff base paper as the face layer. When impacted, stress is rapidly transmitted along the flute and face paper, resulting in high peak acceleration. The corners and bottom of the box are prone to "hard contact," causing damage to the contents, especially under complex conditions such as multi-stage transportation, conveyor belt drops, mechanical clamping, and long-term vibration. While existing self-locking cardboard boxes achieve glue-free, quick assembly, and flat-lay transportation, their structural designs mostly focus on folding methods and locking mechanisms, lacking effective consideration for internal energy absorption and stress cushioning. They still cannot get rid of the dependence on external cushioning materials. If performance is improved by simply increasing the cardboard weight or thickening the corrugated board, it will not only lead to increased weight and cost, but also have limited improvement in resistance to peak impact, making it difficult to balance protection, lightweighting, and sustainability. Utility Model Content

[0003] The present invention aims to provide a self-locking cardboard box using flexible corrugated cardboard, which improves the packaging's resistance to drops and compression of the contents without adding extra lining material.

[0004] To achieve the above objectives, this utility model provides the following technical solution:

[0005] A self-locking cardboard box using flexible corrugated cardboard includes an integral cardboard unfolding sheet and a locking plate with identical layer structures. The integral cardboard unfolding sheet has several self-retaining grooves along the folding path required for box forming, serving as fold lines. The integral cardboard unfolding sheet has self-locking structures on opposite sides. After folding along the grooves, the two side structures move towards each other and interlock through the self-locking structures, forming a cardboard box frame including a front panel, a back panel, and two side panels, with the top and bottom remaining open. The locking plate is then joined to the top and bottom of the cardboard box frame through the self-locking structures to form a complete box body. The integral cardboard unfolding sheet is composed of an outer liner, corrugated core paper, and an inner liner layer that combines flexibility and moisture resistance. Recycled paper fiber flakes are filled into the flutes of the corrugated core paper as a soft protective layer. The recycled paper fiber flakes are continuously distributed along the board surface and are jointly limited and fixed by the inner and outer liner layers in the thickness direction.

[0006] Furthermore, the outer liner is made of conventional cardboard, specifically one of white cardboard, coated white cardboard, or kraft paper, with a basis weight of 200-400 g / m³. 2 .

[0007] Furthermore, the corrugated core paper is used to form a single-layer structure of E-flute, B-flute or C-flute, or a double-layer structure of EB-flute or BC-flute, and the total thickness of the paperboard is 1.2-4.5 mm.

[0008] Furthermore, the inner lining layer uses a basis weight of 120-300 g / m³. 2 Flexible kraft paper with a longitudinal elongation at break ≥2.0% and a 30min Cobb ≤40g / m². 2 Its moisture-proof performance.

[0009] Furthermore, the self-locking structure adopts a mortise and tenon self-locking structure, specifically including a tenon tongue and a matching mortise. A side mortise is opened on one side edge of the integrated cardboard unfolded sheet, and a matching tenon tongue is set on the opposite side edge to realize the structural connection when the two sides are spliced ​​together. Locking end mortises are opened on the free end edges of the top and bottom of the cardboard box frame formed after the integrated cardboard unfolded sheet is folded, and a limiting shoulder is integrally set at the corresponding position of the locking plate. After the integrated cardboard unfolded sheet is folded along the pressure groove, the tenon tongue is inserted into the side mortise, and the limiting shoulder is embedded in the locking end mortise, realizing multi-point self-locking and glue-free fixation of the cardboard box.

[0010] Furthermore, the effective width W of the tenon satisfies 1.1T≤W≤2.0T; in the folded state of the cardboard box, the limiting shoulder on the tenon has an interference fit with the side edge of the corresponding mortise, and the interference amount Δ satisfies: 0.2T≤Δ≤0.6T, where T is the total thickness of the cardboard.

[0011] Furthermore, the self-retained pressure grooves are arranged at equal intervals or in segments according to the box-shaped outline.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] This invention features a cardboard structure composed of an outer liner, corrugated core paper, and an inner liner. By filling the flutes of the corrugated core paper with recycled paper fiber flakes to form a soft protective layer, it effectively widens and reduces the impact peak, significantly improving the cardboard's energy absorption capacity and cushioning effect. It eliminates the need for additional foam, air bags, or other liner materials, thus reducing packaging material usage and packing time. Furthermore, the soft protective layer is derived from recycled paper fibers, making the entire box a single, all-paper material, facilitating recycling and reuse. This design ensures protective performance while also considering assembly efficiency and environmental requirements. The inner liner uses flexible kraft paper, which conforms to its shape during impact and rebound to absorb energy while maintaining the necessary edge pressure and stacking strength, achieving a "flexible yet strong" structural performance. The tenon-and-mortise self-locking structure, combined with self-retaining pressure grooves, allows for rapid box assembly within 3-5 seconds, suitable for automatic / semi-automatic assembly processes. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0015] Figure 2 This is a schematic diagram of the structure of the integrated cardboard unfolding sheet of this utility model in its unfolded state;

[0016] Figure 3 This is a schematic diagram of the locking plate structure of this utility model;

[0017] Figure 4 This is a cross-sectional schematic diagram of a one-piece cardboard unfolded sheet.

[0018] In the diagram: 1-Integrated cardboard unfolding sheet; 11-Outer liner; 12-Corrugated core paper; 13-Inner liner; 14-Recycled paper fiber lint; 2-Self-retaining groove; 3-Tongue tongue; 4-Mortise; 4a-Side mortise; 4b-Locking end mortise; 5-Locking plate; 51-Limiting shoulder. Detailed Implementation

[0019] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the utility model will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0020] like Figure 1 , 2As shown in Figure 3, the self-locking cardboard box using flexible corrugated cardboard described in this embodiment includes an integral cardboard unfolding sheet 1 and a locking plate 5 with identical layer structures. Several self-retaining grooves 2 are provided on the integral cardboard unfolding sheet 1 according to the folding path required for box forming. The self-retaining grooves 2 are formed by die-cutting and creasing processes and are arranged at equal intervals or in segments according to the box outline, serving as fold lines to achieve precise folding and forming. The integral cardboard unfolding sheet 1 has self-locking structures on opposite sides. After the integral cardboard unfolding sheet 1 is folded along the grooves 2, the two side structures move towards each other and are spliced ​​together through the self-locking structures to form a cardboard box frame including a front panel, a back panel, and two side panels. At this time, the top and bottom remain open. The locking plate 5 is spliced ​​and combined with the top and bottom of the cardboard box frame through the self-locking structures to form a complete box body.

[0021] This self-locking structure adopts a mortise and tenon type self-locking structure, specifically including a tenon tongue 3 and a matching mortise 4. A side mortise 4a is provided on one edge of the integrated cardboard unfolding sheet 1, and a matching tenon tongue 3 is provided on the opposite edge to achieve structural connection when the two sides are spliced ​​together. Locking end mortise 4b is provided on the free ends of the top and bottom of the cardboard box frame formed after the integrated cardboard unfolding sheet 1 is folded, and a limiting shoulder 51 is integrally provided at the corresponding position of the locking plate 5. After the integrated cardboard unfolding sheet 1 is folded along the pressure groove 2, the tenon tongue 3 is inserted into the side mortise 4a, and the limiting shoulder 51 is embedded into the locking end mortise 4b, achieving multi-point self-locking and glue-free fixation of the cardboard box. The mortise and tenon type self-locking structure, combined with the self-retaining pressure groove, can quickly assemble the box within 3-5 seconds, adapting to automatic / semi-automatic assembly processes. The effective width W of the tenon tongue 3 satisfies 1.1T≤W≤2.0T; when the cardboard box is folded and formed, the limiting shoulder on the tenon tongue 3 has an interference fit with the side edge of the corresponding mortise 4, and the interference amount Δ satisfies: 0.2T≤Δ≤0.6T, where T is the total thickness of the cardboard.

[0022] like Figure 4 As shown, the integrated cardboard sheet 1 is composed of an outer liner layer 11, a corrugated core paper 12, and an inner liner layer 13. Recycled paper fiber lint 14 is filled into the flutes of the corrugated core paper 12 as a soft defense layer. The areal density of the recycled paper fiber lint is 80–120 g / m², and its volume fraction in the flute grooves is 30%–65%. The recycled paper fiber lint 14 is continuously distributed along the board surface and is jointly constrained and fixed in the thickness direction by the inner and outer liner layers. By filling the flutes of the corrugated core paper 12 with recycled paper fiber lint 14 to form a soft defense layer, the impact peak is effectively widened and reduced, significantly improving the energy absorption capacity and cushioning effect of the cardboard body. This eliminates the need for additional foam, air bags, or other liner materials, thereby reducing packaging material usage and packing time.

[0023] Outer liner 11 is a conventional cardboard, selected from white cardboard, coated white board (grey-backed white board), or kraft paper, with a basis weight of 200-400 g / m³.2 The inner lining layer 13 uses a basis weight of 120–300 g / m³. 2 Flexible kraft paper with a longitudinal elongation at break ≥2.0% and a 30min Cobb ≤40g / m². 2 Its moisture-proof performance allows it to conform to its shape and dissipate energy during impact and rebound, while maintaining the required edge pressure and stacking strength, achieving a "flexible yet strong" structural performance. The corrugated core paper 12 is selected from any single-layer structure of E-flute, B-flute, and C-flute, or a double-layer combination such as EB-flute and BC-flute, with a paperboard thickness of 1.2-4.5mm.

Claims

1. A self-locking cardboard box made of flexible corrugated cardboard, characterized in that, The integrated cardboard unfolding sheet (1) and locking plate (5) with the same layer structure are provided. Several self-retained pressure grooves (2) are provided on the integrated cardboard unfolding sheet (1) according to the folding path required for the box forming as fold lines. The integrated cardboard unfolding sheet (1) has self-locking structures on opposite sides. After the integrated cardboard unfolding sheet (1) is folded along the pressure grooves (2), the two side structures will move towards each other and splice each other through the self-locking structure to form a cardboard box frame including the front plate, back plate and two side plates. At this time, the top and bottom remain open. The locking plate (5) is spliced ​​and combined with the top and bottom of the cardboard box frame through the self-locking structure to form a complete box. The integrated cardboard unfolding sheet (1) is composed of an outer liner (11), a corrugated core paper (12) and an inner liner (13) which has both flexibility and moisture-proof properties. Recycled paper fiber flakes (14) are filled in the flutes of the corrugated core paper (12) as a soft defense layer. The recycled paper fiber flakes (14) are continuously distributed along the board surface and are jointly limited and fixed by the inner and outer liner in the thickness direction.

2. A self-locking cardboard box using flexible corrugated cardboard as described in claim 1, characterized in that, The outer lining layer (11) is selected from white cardboard, coated white board paper or kraft paper, with a basis weight of 200-400 g / m².

3. A self-locking cardboard box using flexible corrugated cardboard as described in claim 1, characterized in that, The corrugated core paper (12) forms a corrugated structure that is any single-layer structure of E-flute, B-flute or C-flute, or any double-layer structure of EB-flute or BC-flute, and the total thickness of the paperboard is 1.2-4.5 mm.

4. A self-locking cardboard box using flexible corrugated cardboard as described in claim 1, characterized in that, The inner lining layer (13) is made of flexible kraft paper with a basis weight of 120-300 g / m², a longitudinal breaking elongation of ≥2.0%, and a moisture-proof performance of 30min Cobb ≤40 g / m².

5. A self-locking cardboard box using flexible corrugated cardboard as described in any one of claims 1-4, characterized in that, The self-locking structure adopts a mortise and tenon self-locking structure, specifically including a tenon (3) and a matching mortise (4). A side mortise (4a) is opened on one side edge of the integrated cardboard unfolding piece (1), and a matching tenon (3) is set on the opposite side edge to realize the structural connection when the two sides are spliced ​​together. A locking end mortise (4b) is opened on the free end edge of the top and bottom of the cardboard box frame formed after the integrated cardboard unfolding piece (1) is folded, and a limiting shoulder (51) is integrally set at the corresponding position of the locking plate (5). After the integrated cardboard unfolding piece (1) is folded along the pressure groove (2), the tenon (3) is inserted into the side mortise (4a), and at the same time, the limiting shoulder (51) is embedded in the locking end mortise (4b) to realize the multi-point self-locking and glue-free fixation of the cardboard box.

6. A self-locking cardboard box using flexible corrugated cardboard as described in claim 5, characterized in that, The effective width W of the tenon (3) satisfies 1.1T≤W≤2.0T; when the paper box is folded and formed, the limiting shoulder on the tenon (3) and the side edge of the corresponding mortise (4) have an interference fit, and the interference amount Δ satisfies: 0.2T≤Δ≤0.6T, where T is the total thickness of the paperboard.

7. A self-locking cardboard box using flexible corrugated cardboard as described in claim 1, characterized in that, The self-retained pressure groove (2) is arranged at equal intervals or in segments according to the box-shaped outline.

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