A connecting device for double-nosed pipes and double-nosed shower pipes

Abstract

The application provides a connecting device for a double-coupling pipe, which is used for being inserted into the double-coupling pipe and being screwed with an outer pipe of the double-coupling pipe; a part of the connecting device inserted into the double-coupling pipe is provided with a spiral thread matched with the outer pipe; the thread cross-section width changes periodically along the extending direction of the spiral thread; in one change period, the thread cross-section width gradually increases from A11 to A21 and then decreases from A21 to A12, and A11A12; in the next change period, the thread cross-section width gradually increases from A12 to A22 and then decreases from A22 to A13, and A12A13, A21A22; wherein A11, A12 and A13 are the thread cross-section widths under a first intercepting surface, and A21 and A22 are the thread cross-section widths under a second intercepting surface perpendicular to the first intercepting surface. The application further provides a double-coupling shower pipe comprising a double-coupling pipe and the connecting device.

Description

Technical Field

[0001] The present invention relates to a water outlet pipe, and in particular to a double-lock pipe. Background Art

[0002] At present, for most metal double-lock shower hose connecting joints on the market, the cross-sectional width of the thread tooth profile is usually constant, and only a uniform and continuous contact surface is formed between the threads and the inner wall of the metal outer pipe. In daily use, the shower hose is frequently bent, and the internal water pressure continuously impacts the pipe wall. When a user twists the hose to adjust the water outlet angle, the metal outer pipe has a tendency to slip reversely along the helix. The constant cross-section thread cannot form a stepped blocking structure. After long-term repeated stress, the thread engagement gap gradually expands, the thread slowly loosens and separates, and the internal rubber liner loses the protection of the metal outer pipe and is directly exposed, which is very prone to cracking and water leakage. Under extreme working conditions, pipe bursting may occur, resulting in potential safety hazards in use. Summary of the Invention

[0003] The main technical problem to be solved by the present invention is to provide a connecting device for a double-lock pipe, which increases the connection stability between the connecting device and the outer pipe of the double-lock pipe.

[0004] In order to solve the above technical problem, the present invention provides a connecting device for a double-lock pipe, said connecting device being used for being inserted into the double-lock pipe and being threadedly connected with the outer pipe of the double-lock pipe;

[0005] The part of said connecting device inserted into the double-lock pipe is provided with helical threads adapted to said outer pipe; along the spiral extension direction of the threads, the cross-sectional width of the threads changes periodically; within one change cycle, the cross-sectional width of the threads gradually increases from cross-sectional width A11 to A21, and then continues to decrease from A21 to A12, and A11<A12; in the next change cycle, the cross-sectional width of the threads gradually increases from A12 to A22, and then continues to decrease from A22 to A13, and A12<A13, A21<A22;

[0006] wherein A11, A12 and A13 are thread cross-sectional widths under a first cutting section, and A21 and A22 are thread cross-sectional widths under a second cutting section perpendicular to the first cutting section.

[0007] In a preferred embodiment: every 180° rotation of the helical thread along the circumference constitutes one change cycle.

[0008] In a preferred embodiment: within one change cycle, the thread cross-sectional width A2 measured at any position under the second cutting section and the thread cross-sectional width A1 measured at any position under the first cutting section satisfy: 1<A2 / A1≤3.

[0009] In a preferred embodiment: within a change cycle, the thread section width A2 measured at any position under the second cutting surface and the thread section width A1 measured at any position under the first cutting surface satisfy: 1.2≤A2 / A1≤2.

[0010] In a preferred embodiment: Pa is defined as the pitch of the connecting device, Ph is the pitch of the double-threaded outer tube that mates with the connecting device, Ca is the maximum outer diameter of the insertion section of the connecting device, Ch is the inner diameter of the connecting device, and t is the wall thickness of the outer tube; wherein Ph≥Pa+0.05mm, Ch≥Ca+2t+0.05mm.

[0011] In a preferred embodiment: the length of the threaded section of the connecting device inserted into the double-threaded tube is L, and the length L includes at least 1.5 connecting device pitches Pa.

[0012] In a preferred embodiment: the length of the threaded section of the connecting device inserted into the double-threaded tube is L, and the length L includes 2 to 4 thread pitches Pa.

[0013] In a preferred embodiment: an arc transition surface is provided at the position corresponding to the maximum width of the thread cross section during a change cycle.

[0014] The present invention also provides a double-lock shower tube, including a double-lock tube and the above-mentioned connecting device, wherein the outer tube of the double-lock tube has an internal thread adapted to the helical thread of the connecting device.

[0015] In a preferred embodiment, a metal fitting is further included, which is sleeved on the outside of the outer tube and cooperates with the connecting device to form a chamber for clamping and fixing the outer tube.

[0016] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0017] This invention provides a connection device for double-threaded hoses, which features a periodically undulating and progressively widening thread cross-section along the extension direction of the helical thread. Two sets of mutually perpendicular cut surfaces define the thread width, creating multi-level raised nodes and a bidirectional irregular engagement profile. After engagement, the raised nodes exert localized pressure on the double-threaded hose to increase friction and prevent reverse thread slippage. Simultaneously, the bidirectional structure disperses torsional stress. Combined with the progressively widening structure, it adapts to the concentrated stress conditions at the hose opening, effectively improving the problem of thread loosening, enhancing connection stability, delaying thread wear, and extending service life. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the connecting device on the first cut surface in a preferred embodiment of the present invention;

[0019] Figure 2 This is a schematic diagram of the connecting device on the second cut surface in a preferred embodiment of the present invention;

[0020] Figure 3 This is a front view of the connecting device in a preferred embodiment of the present invention;

[0021] Figure 4 This is a cross-sectional view of T3 at position AA;

[0022] Figure 5 This is a schematic diagram of the double-loop outer tube in a preferred embodiment of the present invention;

[0023] Figure 6 This is an exploded view of the shower double-loop pipe in a preferred embodiment of the present invention;

[0024] Figure 7 This is an assembly diagram of the shower double-loop hose in a preferred embodiment of the present invention; Detailed Implementation

[0025] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0026] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0028] In the description of this embodiment, the terms "upper," "lower," "right," and "left," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0029] refer to Figure 1-7 This embodiment provides a connecting device 10 for a double-loop hose, consisting of two parts: an insertion section 1 and a limiting flange 2. The outer diameter of the insertion section 1 matches the inner diameter of the outer tube 3 of the double-loop hose, allowing it to be inserted into the double-loop hose. The outer diameter of the limiting flange 2 is larger than the inner diameter of the outer tube 3. During assembly, the flange abuts against the end face of the outer tube 3, limiting the insertion depth of the insertion section 1 and preventing it from completely sliding into the outer tube 3. A through-hole is provided in the center of the insertion section 1 to ensure complete water flow in the shower circuit. The outer wall of the insertion section 1 is provided with a continuous helical thread for engaging with the internal thread of the outer tube 3.

[0030] In this embodiment, one side of the flange connecting the shaft is defined as the beginning end and the other side as the end end, with the helical thread extending from the end end to the beginning end. Along the direction of helical extension, the width of the helical thread cross-section on the outer wall of the insertion section 1 will exhibit continuous periodic fluctuations. Within any complete cycle, the thread cross-section width will gradually increase from the basic cross-section width A11 at the end of the previous cycle until it reaches the peak cross-section width A21. Subsequently, the cross-section width will continue to decrease until it changes to the next basic cross-section width A12, with the dimensional relationship satisfying A11 < A12. After entering the next complete cycle, the thread cross-section width will continue to gradually increase from A12 to the peak cross-section width A22, and then decrease from A22 to A13, simultaneously satisfying the progressive dimensional constraints of A12 < A13 and A21 < A22.

[0031] For ease of explanation, this embodiment sets two sets of mutually perpendicular cutting surfaces, defined as the first cutting surface and the second cutting surface, respectively. A11, A12, and A13 are the cross-sectional widths measured after cutting the thread along the first cutting surface, and A21 and A22 are the cross-sectional widths measured after cutting the thread along the second cutting surface perpendicular to the first cutting surface. This bidirectional perpendicular cutting surface size design can significantly improve the thread anti-loosening effect from a mechanical perspective. Traditional threads only have a single fixed cross-sectional size and can only provide frictional resistance in a single force direction. However, in this solution, the cross-sectional width of the two sets of perpendicular cutting surfaces fluctuates simultaneously, and the thread profile forms an irregular meshing profile. When meshing with the internal thread of the metal outer tube 3, the number of contact points is greatly increased. When the hose is subjected to torsional force in any direction, the contact points in both perpendicular directions can simultaneously distribute and offset the torsional stress, and there will be no situation of stress concentration in a single direction that wears the thread. Meanwhile, the undulating structure of the thread widening to the peak and then falling back in each change cycle will form local protruding nodes on the thread helical path. The protruding nodes form a slight interference fit with the inner wall of the outer tube 3, and the static friction in the contact area is significantly increased. Once the outer tube 3 shows a reverse loosening rotational tendency, the protruding nodes will directly get stuck inside the tooth groove of the inner thread of the outer tube 3, forming a physical blocking limit, thereby preventing the thread from sliding and loosening in the reverse direction.

[0032] This embodiment further defines a complete dimensional change cycle as each 180° rotation of the helical thread along the circumference. This corresponds to a complete dimensional fluctuation transformation of "A1 basic width - A2 peak width - next level A1 basic width" for half a turn of the thread. On the helical path of a dimensional change cycle, the 0° position corresponds to the cross-sectional width A11 below the first section surface. A 90° rotation switches to the second section surface, corresponding to the peak cross-sectional width A21. Continuing to rotate 180° back to the first section surface, the dimension falls back to the cross-sectional width A12, thus completing a complete change cycle. The reason for defining a complete dimensional change cycle as each 180° rotation of the helical thread along the circumference is that if the rotation angle of a dimensional change cycle is too small, such as 90°, the distribution of protruding nodes is too dense, and the compressive stress on the pipe wall between adjacent protruding nodes will overlap, easily causing local deformation and indentation of the thin-walled metal outer tube 3. If the rotation angle of a dimensional change cycle is too large, such as 270°, the distribution of protruding nodes on the helical path is too sparse, failing to form continuous multi-level blocking and limiting, significantly reducing the anti-loosening effect. The 180° half-circle arrangement can balance the distribution density of the protruding nodes, ensuring that the multi-level friction blocking structure is evenly distributed throughout the spiral, and preventing the metal outer tube wall from being damaged by excessively dense protruding nodes.

[0033] Within the same change cycle, the ratio of the thread cross-sectional width A2 measured at any position under the second cutting surface to the thread cross-sectional width A1 measured at any position under the first cutting surface satisfies 1 < A2 / A1 ≤ 3. If the ratio of A2 / A1 is equal to 1, it means that the cross-sectional widths of the two sets of vertical cutting surfaces are completely consistent, the thread profile returns to the conventional cylindrical profile, the bidirectional protrusion friction limiting structure directly fails, and the design purpose of multi-directional stress dispersion and multi-point blocking loosening cannot be achieved. If the ratio of A2 / A1 is greater than 3, the peak width of the second cutting surface will increase excessively, the thread protrusion size will be too high, and the protrusion will forcibly squeeze the inner wall of the metal outer tube 3 during assembly and screwing. The thin-walled double-threaded tube is very prone to deformation and cracking. At the same time, the excessively high protrusion will greatly increase the assembly screwing resistance. In this embodiment, the ratio of A2 / A1 is further limited to 1.2≤A2 / A1≤2. Within this range, the interference of the thread protrusion is moderate, the static friction coefficient reaches its peak, the anti-torsional loosening performance is optimal, and the assembly screwing torque is within the range that can be easily operated by manual assembly. There will be no problems such as assembly jamming or pipe wall deformation. It has strong practicality in mass production assembly scenarios.

[0034] This solution also clearly defines the mating dimensions of the thread and the outer tube 3. Pa is defined as the thread pitch of the connecting device 10 itself, Ph is the thread pitch of the double-threaded outer tube 3 that mates with the connecting device 10, Ca is the maximum outer diameter of the insertion section 1 of the connecting device 10, Ch is the inner diameter of the insertion section 1 of the connecting device 10, and t is the wall thickness of the double-threaded tube. The dimensional relationship satisfies Ph≥Pa+0.05mm and Ch≥Ca+2t+0.05mm. Ch minus twice the wall thickness 2t is the inner diameter of the outer tube 3. By setting the inner diameter of the outer tube 3 to be larger than the maximum outer diameter of the insertion section 1 of the connecting device 10 and reserving an assembly gap of 0.05mm, it is ensured that the insertion section 1 of the connecting device 10 can be smoothly inserted into the outer tube 3 without interference, avoiding the situation of insertion jamming or failure to be in place due to machining tolerances. The dimensional constraint Ph≥Pa+0.05mm is set to allow for thread assembly clearance. If the difference between the pitch of the outer tube 3 and the pitch of the connecting device 10 is less than 0.05mm, the thread profile will fit completely tightly when the threads are screwed on. After water is supplied, the thermal expansion and contraction of the pipeline will cause the threads to jam, making it impossible to separate the joint and hose during later disassembly and maintenance. The minimum difference of 0.05mm can reserve a small thermal expansion compensation clearance, taking into account both assembly tightness and later disassembly performance. The inner diameter constraint Ch≥Ca+2t+0.05mm is used to ensure that the insertion section 1 can be smoothly inserted into the metal outer tube 3. Ca is the outer diameter of the outer tube 3, and 2t represents the metal wall thickness on both sides of the tube wall. The additional 0.05mm assembly clearance avoids the situation where the insertion section 1 is stuck or cannot be in place when there is an outer diameter tolerance in the production process of the metal outer tube 3.

[0035] Furthermore, in this embodiment, the total length of the threaded section of the connecting device 10 inserted into the outer tube 3 is denoted as L. The length L must contain at least 1.5 thread pitches Pa of the connecting device 10. Setting 1.5 thread pitches as the minimum length limit ensures that the insertion section 1 has at least one complete dimensional change cycle, forming at least one set of A11-A21-A12 raised blocking structures. If the effective thread length is less than 1.5 thread pitches, only a half-section of incomplete periodic fluctuations will exist, failing to form a complete multi-level friction limit, significantly reducing the anti-loosening effect and failing to solve the problem of hose loosening and leakage. In actual mass production, it is further preferred that the threaded section length L contains 2 to 4 thread pitches Pa. 2 to 4 thread pitches correspond to 2 to 4 complete dimensional change cycles, with multi-level progressively widening raised nodes evenly distributed along the spiral path, forming a continuous gradient anti-loosening structure. If there are more than 4, the assembly resistance will be too high, increasing unnecessary material costs.

[0036] In each variation cycle, a rounded transition surface is provided at the protrusion position where the thread cross-sectional width reaches its maximum value, eliminating the sharp right-angle transition structure of traditional threads. This allows the rounded transition to smoothly guide the internal thread of the outer metal tube 3 into place during assembly and engagement, preventing sharp edges from scratching the metal plating on the inner wall of the outer metal tube 3, thus preventing plating peeling, rust, and corrosion of the pipeline. Secondly, the rounded transition can disperse local stress at the peak position of the protrusion. When the pipeline is bent and subjected to force, there will be no stress concentration point at the contact point between the thread protrusion and the pipe wall, preventing the thin-walled metal pipe from being pressed into cracks by sharp edges. At the same time, the rounded transition increases the contact area between the thread and the metal pipe wall, reducing the contact pressure per unit area and significantly slowing down the wear rate between the thread and the pipe wall. Even after long-term use, it can maintain stable frictional resistance and will not experience loosening or failure due to rapid wear.

[0037] This embodiment further provides a double-lock shower pipe, including a double-lock pipe and the above-mentioned connecting device 10. The outer tube of the double-lock pipe has an internal thread that matches the spiral thread of the connecting device 10. The double-lock pipe is composed of an outer tube 3 and an inner tube 4. The connecting device 10 is screwed into the pipe opening of the outer tube 3, and the limiting flange 2 fits against the end face of the pipe opening to complete the assembly. It is suitable for installation and use in household shower water outlet and water inlet pipes.

[0038] The double-lock shower pipe is also equipped with a metal kit 5. The metal kit 5 is fitted onto the outside of the metal outer tube 3 of the double-lock pipe. After assembly, the metal kit 5 and the inner connecting device 10 cooperate with each other to form a sealed chamber that clamps and fixes the metal outer tube 3, forming a double clamping and anti-loosening system.

[0039] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A connecting device for double-loop pipes, characterized in that: The connecting device is configured to be inserted into a double-coupled pipe and be in threaded connection with an outer pipe of the double-coupled pipe; A portion of the connecting device inserted into the double-coupled pipe is provided with a helical thread adapted to the outer pipe; along the helical extension direction of the thread, the thread cross-sectional width varies periodically; within one variation cycle, the thread cross-sectional width gradually increases from a cross-sectional width A11 to A21, and then continues to decrease from A21 to A12, with A11<A12; in the next variation cycle, the thread cross-sectional width gradually increases from A12 to A22, and then continues to decrease from A22 to A13, with A12<A13 and A21<A22; wherein A11, A12 and A13 are thread cross-sectional widths on a first cutting plane, and A21 and A22 are thread cross-sectional widths on a second cutting plane perpendicular to the first cutting plane.

2. The connecting device for a double-loop tube according to claim 1, characterized in that: Every 180° rotation of the helical thread along the circumference constitutes one variation cycle.

3. A connecting device for double-loop tubes according to claim 1, characterized in that: Within one variation cycle, for any position on the second cutting plane and any position on the first cutting plane, the measured thread cross-sectional width A2 and thread cross-sectional width A1 satisfy: 1<A2 / A1≤3.

4. A connecting device for a double-loop pipe according to claim 1, characterized in that: Within one variation cycle, for any position on the second cutting plane and any position on the first cutting plane, the measured thread cross-sectional width A2 and thread cross-sectional width A1 satisfy: 1.2≤A2 / A1≤2.

5. A connecting device for a double-loop pipe according to any one of claims 1-4, characterized in that: Defining Pa as the pitch of the connecting device, Ph as the pitch of the outer pipe of the double-coupled pipe mated with the connecting device, Ca as the maximum outer diameter of the cannula section of the connecting device, Ch as the inner diameter of the connecting device, and t as the wall thickness of the outer pipe; wherein Ph≥Pa+0.05mm and Ch≥Ca+2t+0.05mm.

6. A connecting device for a double-loop tube according to claim 5, characterized in that: The length of the threaded section of the connecting device inserted into the double-coupled pipe is L, and at least 1.5 pitches Pa of the connecting device are included within the length L.

7. A connecting device for a double-loop tube according to claim 5, characterized in that: The length of the threaded section of the connecting device inserted into the double-coupled pipe is L, and 2 to 4 pitches Pa are included within the length L.

8. The connecting device for a double-loop tube according to claim 1, characterized in that: A circular arc transition surface is provided at the position corresponding to the maximum thread cross-sectional width in one variation cycle.

9. A double-lock shower pipe, characterized in that: Comprises a double-coupled pipe and the connecting device according to any one of claims 1 to 8, wherein the outer pipe of the double-coupled pipe has an internal thread adapted to the helical thread of the connecting device.

10. A double-interlocking shower pipe according to claim 9, characterized in that: Further comprises a metal sleeve, wherein the metal sleeve is sleeved outside the outer pipe and cooperates with the connecting device to form a chamber for clamping and fixing the outer pipe.

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