An isoelectric wide-in-surface thread plastic pipe fitting and an insert structure matched therewith
By increasing the bend radius of plastic pipe fittings and the outer diameter of the inserts, combined with the composite surface's anti-leakage and anti-torsion structure, the pressure loss and leakage problems at water flow bends in traditional plastic composite pipe fittings have been solved, and the strength and anti-torsion function of the inserts have been improved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- SHANGHAI TIANLI IND CO LTD
- Filing Date
- 2025-08-11
- Publication Date
- 2026-07-07
AI Technical Summary
Traditional plastic composite pipe fittings suffer from significant pressure loss at water flow bends, and their insert strength, leak-proof and torsion-proof functions are not comprehensive enough. The equipotential boss structure also poses a risk of leakage.
Design an equipotential wide-face internally threaded plastic pipe fitting, increase the radius of the bend, increase the outer diameter of the insert and the width of the thread end face, and set a composite surface anti-leakage and anti-torsion structure, including rectangular grooves, dovetail grooves and wedge grooves, to enhance the bonding effect between the insert and the plastic.
It enables smooth water flow, enhances the strength and leak-proof function of the insert, avoids potential leakage risks, and improves anti-torsion ability.
Smart Images
Figure CN224469919U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of pipe connector technology, and further includes the field of plastic composite pipe fittings and their threaded connections and the field of equipotential bonding technology for building pipes. More specifically, it relates to a plastic composite pipe fitting, an embedded wide-face internal thread insert, and a matching insert equipotential bonding structure. Background Technology
[0002] Plastic composite pipe fittings are generally made of plastic (such as polypropylene PP-R) composite metal (such as copper alloy) inserts. Furthermore, equipotential bonding bolt holes are provided on the metal inserts and extend through to the outer wall of the plastic composite pipe fitting, enabling connection with the building's equipotential bonding system and achieving equipotential protection between the pipeline and the building. For example... Figure 1 and Figure 2 The diagram shows a traditional equipotential internal threaded plastic composite pipe fitting structure. Traditional elbows, tees, and other plastic composite pipe fittings that enable water flow bends typically have a spherical bend with an arc radius of SR, and a straight section transitioning to the bend that is a cylinder with an outer diameter of d0. SR is 0.5 times d0 (also known as a right-angle bend with a bending radius of 0°). This causes collisions, backflow, and significant pressure losses when water flows through elbows or tees, hindering smooth water flow.
[0003] The internal threaded inserts (including equipotential inserts) of plastic composite pipe fittings are generally made of brass or other metals, embedded in the plastic pipe fittings. They must meet the requirements for threaded connection strength, including reasonable tightening expansion force and a reasonable range of impact force. Necessary grooves must also be designed to prevent leakage during use, including pressure changes when the pipe is opened and closed, and the effects of thermal expansion and contraction due to temperature changes. Furthermore, necessary structures must be designed to prevent the torsional forces generated during thread tightening during installation and use, including changes in the circumferential shape of the insert's external or internal contact surface with the plastic, and changes in the concave and convex shape of the insert's bottom surface. The equipotential structure is designed as a boss that penetrates to the outer wall of the plastic composite pipe fitting, and is equipped with equipotential bonding terminals to connect to the building's equipotential bonding system after subsequent pipe installation.
[0004] Traditional plastic composite pipe fittings feature locally reinforced internal thread inserts at the opening end to increase the end face width. Their anti-leakage grooves are typically designed with three outer wall grooves and one bottom groove, usually employing a dovetail structure. Their anti-torsion structure generally uses 4-6 protruding claws, 2-3mm high, added to the bottom surface to prevent destructive circumferential displacement of the insert under circumferential torsional force. Their equipotential bosses are generally peninsula-shaped, extending through the outer wall and opening end of the plastic composite pipe fitting, forming an opening gap with the plastic shell. Due to inconsistent cooling and shrinkage during injection molding, the gap is noticeable, creating a visually apparent risk of leakage.
[0005] Traditional plastic composite pipe fittings (including equipotential bonding structures) fulfill basic pipe connection and flow functions, basic insert strength, leak-proof and anti-torsion functions, and basic equipotential bonding protection functions. However, with the increasing market demand for personalization and higher quality, existing plastic composite pipe fittings still suffer from significant pressure loss at water bends. Their insert strength, leak-proof and anti-torsion functions are not comprehensive enough and are not readily apparent. Furthermore, their equipotential bonding structure creates an opening that penetrates the outer wall and the end, indicating areas for improvement. Utility Model Content
[0006] The purpose of this invention is to provide an equipotential wide-face internally threaded plastic pipe fitting and a matching insert structure.
[0007] To solve the above-mentioned technical problems, as a first aspect, the technical solution of this utility model is as follows: an equipotential wide-face internally threaded plastic pipe fitting, comprising a plastic shell, wherein the plastic shell is sequentially provided with a straight cylindrical portion of the socket end, a curved arc portion tangentially transitioning to the socket end, and a threaded end, the threaded end being used to embed an equipotential insert; the inner cavity of the socket end is connected to the end of the curved arc portion, which is divided into a cylinder with a reduced step, having an inner diameter of D1, and the inner arc radius of the curved arc portion is R1, where R1≥D1; the inner cavity channel of the threaded end is a cylinder with an inner diameter of D2; the flow channel of the curved arc portion smoothly narrows from a cylinder with an inner diameter of D1 to a cylinder with an inner diameter of D2, allowing water to flow smoothly within the curved channel.
[0008] Furthermore, the socket end is a cylinder with an outer diameter of d and an inner diameter of D, connecting to the matching pipe and the bend arc portion; the outer arc radius of the bend arc portion is R, where R≥d.
[0009] As a second aspect, the present invention also provides an insert structure that matches the above-mentioned equipotential wide-face internal threaded plastic pipe fitting, including an equipotential insert that is embedded and connected to the plastic shell, comprising a partially exposed cylindrical end, an equipotential boss embedded in the threaded end, and an equipotential connection screw hole.
[0010] According to this utility model, the equipotential boss of the equipotential insert is embedded in the plastic shell to form an island, penetrating to the outer wall of the plastic shell. The closest distance to the periphery of the plastic shell is the distance A from the end face of its threaded end, where A≥2mm, so that a small closed-loop gap is formed with the plastic shell after injection molding and cooling. An equipotential connection screw hole is provided in the center of the equipotential boss to connect with the building equipotential device after subsequent installation of pipes.
[0011] According to this utility model, the cylindrical end of the equipotential insert is set as a cylinder with an outer diameter of d1. The outer diameter d1 dimension ensures that the outer circle and the threaded end face connected to the threaded end are widened by more than 1.5 times. The exposed part of the cylindrical end after being embedded in the plastic shell has a length of L2, which is 3mm to 5mm, thereby improving the strength of the insert end.
[0012] According to this utility model, a rectangular groove with a partitioning function is formed on the inner side of the cylindrical end, and at least a narrow groove and a dovetail groove, a radial single-sided wedge groove at the tail end, an inner cavity channel positioning hole at the threaded end, and a circumferentially distributed protrusion at the tail end are formed on the outer circle of the central cylinder where the equipotential boss is located.
[0013] According to this utility model, the rectangular groove forms a partition at the end of the cylindrical part where the equipotential boss extends; a narrow groove is provided on each side of the equipotential boss, and after injection molding, the rectangular groove and the narrow groove on the front side of the equipotential boss are embedded into the plastic shell with the lower part of the cylindrical end to form a plastic and metal concave-convex structure, thereby achieving excellent composite surface anti-leakage function.
[0014] According to this utility model, the dovetail groove is further provided on the outer side of the tail end of the central cylinder, and the groove depth is consistent with the groove depth of the narrow groove; the single-sided wedge groove is provided on the inner side of the tail end of the equipotential insert, located between the positioning hole with an inner diameter of D2 and the injection channel of the single-sided wedge groove with an inner diameter of D3, the injection channel thickness (D3-D2) / 2≥0.5mm, the groove depth C3≥1.2mm, the opening width E4≥2mm, and the single-sided wedge angle a1 on both sides≥15°; the dovetail angle a and the wedge angle a1 of the dovetail groove and the single-sided wedge groove improve the fit of the plastic body with large shrinkage during cooling and shrinkage, and combined with the narrow groove on the rear side of the equipotential boss, after injection molding, a first layer of plastic and metal concave-convex structure is formed to prevent leakage, thereby achieving excellent composite surface anti-leakage function.
[0015] According to this utility model, the protruding claw is located at the tail end of the equipotential insert, and four or more are evenly distributed circumferentially, with a height L4≥2.0mm; the protruding claw, the equipotential boss, and the rectangular groove are inserted into the plastic tube body to form a combined circumferential barrier, further enhancing the anti-torsion function.
[0016] According to this utility model, the equipotential boss is a trapezoid with its long base facing the end face of the equipotential insert, and its height is B, where B ≥ 6 mm; wherein, the partition width E of the rectangular groove is consistent with the width of the long side of the trapezoid of the equipotential boss.
[0017] Compared with the prior art, the beneficial effects of this utility model are:
[0018] The radius of the arc of the plastic shell bend of this utility model is significantly increased, and is not less than the diameter of the cylinder connected to it, so that the water can flow smoothly in the bend channel. At the same time, the length of the socket end is increased by 2mm to 5mm, so that the lengths of the socket end and the threaded end are commensurate.
[0019] The cylindrical end outer diameter of this equipotential insert is more than 4mm larger than that of a conventional equipotential insert of the same model, resulting in a thread end face that is more than 1.5 times wider than the outer diameter. The exposed portion after being embedded in the plastic housing is 3mm to 5mm long, making the enhanced strength of the insert's opening clearly visible. The equipotential boss of this insert forms an island embedded in the plastic housing, extending through the outer wall of the housing. The closest distance between the boss and the periphery of the plastic housing is no less than 2mm, ensuring a small closed-loop gap after injection molding and cooling, thus avoiding any perceived risk of leakage.
[0020] The surface of the material embedded inside the plastic shell is smoothed by sandblasting or other cutting processes to improve the bonding effect with the plastic and enhance the leak-proof function.
[0021] This invention features a composite anti-leakage structure formed on the front side of the equipotential boss. Specifically, this consists of a rectangular groove and a narrow groove on the inner side of the cylindrical end of the equipotential insert head, and a plastic-metal interlocking structure formed by the lower part being embedded into the plastic shell after injection molding. Another composite anti-leakage structure is formed on the rear side of the equipotential boss. This consists of a dovetail groove and a single-sided wedge groove. The dovetail angle and wedge angle structure allow the shrinking plastic body to adhere more tightly to the dovetail and wedge surfaces during cooling and contraction. Combined with the narrow groove, this forms the first interlocking structure of plastic and metal, creating a source of leakage after injection molding. The four or more circumferentially distributed claws at the tail of the equipotential insert, along with the equipotential boss and the rectangular groove, form a combined circumferential barrier when embedded in the plastic pipe body, achieving stronger anti-torsion function and further ensuring the anti-leakage function of the two anti-leakage groove combinations before and after the equipotential boss. Attached Figure Description
[0022] Figure 1 This is a first-view structural schematic diagram of an equipotential internally threaded plastic composite pipe fitting in the prior art.
[0023] Figure 2 This is a second-view structural schematic diagram of an equipotential internally threaded plastic composite pipe fitting in the prior art.
[0024] Figure 3 This is a schematic diagram of the assembly of an equipotential wide-face internally threaded plastic pipe fitting and an equipotential insert according to the present invention.
[0025] Figure 4This is a cross-sectional view of the assembly diagram of an equipotential wide-face internally threaded plastic pipe fitting and an equipotential insert according to the present invention.
[0026] Figure 5 This is a first-view structural schematic diagram of the insert structure of this utility model;
[0027] Figure 6 This is a second-view structural schematic diagram of the insert structure of this utility model;
[0028] Figure 7 This is a third-view structural diagram of the insert structure of this utility model. Detailed Implementation
[0029] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.
[0030] like Figure 3 and Figure 4 As shown in the figure, this application proposes an equipotential wide-face internally threaded plastic pipe fitting and its matching insert structure. The equipotential plastic composite pipe fitting, such as elbows and tees, which enables water flow to bend, has a significantly increased radius of curvature in the bend portion of its plastic shell, allowing water to flow smoothly within the bend channel. This bend-type equipotential wide-face internally threaded plastic pipe fitting structure includes a plastic shell 1 and an equipotential insert 2 embedded therein. The plastic shell 1 is sequentially provided with a straight cylindrical socket end 11, a bend arc portion 12, and a threaded end 13 into which the equipotential insert 2 is embedded. The equipotential insert 2 has a partially exposed cylindrical end 21, an equipotential boss 22 embedded in the threaded end 13, and an equipotential connection screw hole 23.
[0031] The socket end 11 of the plastic shell 1 is a cylinder with an outer diameter of d and an inner diameter of D. The inner diameter is set according to the product standard and connects to the matching pipe and the curved section 12. The end of the inner cavity connecting to the curved section 12 is a cylinder with a reduced step and an inner diameter of D1. The outer radius of the curved section 12 is R, and R≥d is set. The inner radius of the curved section 12 is R1, and R1≥D1 is set. The inner cavity channel of the threaded end 13 is a cylinder with an inner diameter of D2, and the connecting part is a pipe thread with a size of Rp. D2 and Rp are set according to the product standard and the pipe thread. The flow channel of the curved section smoothly shrinks from a cylinder with an inner diameter of D1 to a cylinder with an inner diameter of D2, so that the water can flow smoothly in the curved channel. Meanwhile, the height L1 of its threaded end 13 is set to be consistent with the height of the threaded end of the same type of traditional equipotential internal thread plastic pipe fitting; its socket end 11 is set to transition tangentially with the bend arc portion 12, so that the length L of the socket end 11 is increased by 2mm to 5mm compared with the length L0 of the socket end of the same type of traditional equipotential internal thread plastic pipe fitting, so as to achieve the symmetry of the lengths of the socket end 11 and the threaded end 13.
[0032] like Figures 5 to 7 As shown, the cylindrical end 21 of the equipotential insert 2 is set as a cylinder with an outer diameter of d1. The outer diameter d1 is more than 4mm larger than that of the conventional equipotential insert of the same model, realizing a width of more than 1.5 times between its outer circle and the thread end face of the connecting pipe thread Rp. The exposed part after it is embedded in the plastic shell 1 has a length of L2, which is 3mm to 5mm, making the reinforcement of the insert end strength visually apparent. The equipotential boss 22 of the equipotential insert 2 is embedded in the plastic shell 1 to form an island, penetrating to the outer wall of the plastic shell 1. The closest distance to the periphery of the plastic shell 1 is the distance A from the end face of its threaded end 13, where A≥2mm. This achieves a small closed-loop gap with the plastic shell 1 after injection molding and cooling, avoiding the visual perception of leakage. The equipotential boss 22 can be a trapezoid with its long base facing the end face of the equipotential insert 2, and its height is B, where B≥6mm. An equipotential bonding screw hole 23 is provided at the center of the equipotential boss 22. The screw hole size is M, and it is designed as a standard internal thread M4, so as to connect with the building equipotential device after subsequent pipe installation.
[0033] To improve the anti-leakage and anti-torsion functions of the equipotential insert 2, a rectangular groove 24 with a partitioning function is formed on the inner side of the cylindrical end 21, at least one narrow groove 25 and a dovetail groove 26 are formed on the outer circle of the central cylinder where the equipotential boss 22 is located, a radial single-sided wedge groove 27 is formed at the tail end, an inner cavity channel positioning hole 28 of the threaded end 13 and a circumferentially distributed protrusion 29 at the tail end. The surface of the insert into the plastic shell 1 is smoothed by sandblasting or other cutting processes to increase the bonding effect with the plastic and increase the anti-leakage function.
[0034] Specifically, the cylindrical end 21 has a length of L3, with a portion of its length embedded inside the plastic housing 1. The length of the embedded portion, L3-L2, is ≥1mm. The rectangular groove 24 forms a partition at the point where the equipotential boss 22 extends to the cylindrical end 21. The partition width E can be consistent with the width of the trapezoidal long side of the equipotential boss 22. It can be formed by hot forging in one step and axially demolded towards the cylindrical end 21. Its minor diameter is consistent with the outer diameter d2 of the central cylinder with a draft angle. Its depth is C1 and its width is E1, ensuring that the cylindrical end 21 has sufficient injection molding resistance.
[0035] A narrow groove 25 is provided on both the front and rear sides of the equipotential boss 22, with a width of E2 and a depth of C2. To maintain the anti-leakage effect, E2 ≤ 2.0 mm and C2 ≥ 1.0 mm. After injection molding, the rectangular groove 24 and the narrow groove 25 on the front side of the equipotential boss 22, together with the lower part of the cylindrical end 21, are embedded into the plastic shell 1, forming a plastic and metal interlocking structure that achieves excellent composite surface anti-leakage function.
[0036] The dovetail groove 26 is located on the outer side of the tail end of the central cylinder, with an opening width E3≥2mm, a dovetail angle a≥15°, and a groove depth consistent with the groove depth C2 of the narrow groove 25.
[0037] The single-sided wedge groove 27 is located on the inner side of the tail end of the equipotential insert 2, between the positioning hole 28 with an inner diameter of D2 and the injection channel of the single-sided wedge groove 27 with an inner diameter of D3. The thickness of the injection channel (D3-D2) / 2 ≥ 0.5 mm, the groove depth C3 ≥ 1.2 mm, the opening width E4 ≥ 2 mm, and the single-sided wedge angle a1 on both sides ≥ 15°. The dovetail angle a and wedge angle a1 of the dovetail groove 26 and the single-sided wedge groove 27 make the plastic body with large shrinkage fit more tightly against the dovetail surface and wedge surface when it cools and shrinks. Combined with the narrow groove 25 on the rear side of the equipotential boss 22, it forms the first layer of plastic and metal concave-convex structure that is the source of leakage after injection molding, realizing excellent composite surface anti-leakage function.
[0038] The protruding claw 29 is located at the tail end of the equipotential insert 2, with four or more evenly distributed around its circumference and a height L4 ≥ 2.0 mm. Its outer side can be designed as a cylinder with the same outer diameter d2 as the central cylinder with a draft angle, and its inner side can be designed as a cylinder with an inner diameter D4 coaxial with the outer side. The thickness of the inner and outer sides (d2-D4) / 2 ≥ 2.0 mm. Its left and right sides can be designed as parallel surfaces with a width F, or as tangents perpendicular to the outer circle, forming an approximate trapezoid with inner and outer arcs, a center width F, and a width F ≥ 3.0 mm. The protruding claw 29, together with the equipotential boss 22 and the rectangular groove 24, forms a combined circumferential barrier when embedded in the plastic pipe body, achieving a stronger anti-torsion function and further ensuring the anti-leakage function of the combined anti-leakage grooves before and after the equipotential boss 22.
[0039] Example:
[0040] An equipotential wide-face internal thread plastic pipe fitting and its insert structure, taking a composite pipe fitting with PP-R plastic composite copper alloy equipotential wide-face internal thread insert as an example, taking a 90° equipotential socket wide-face internal thread elbow with a socket end of a household water supply pipe, a socket end of DN25, and an internal thread end of Rp1 / 2 cylindrical pipe thread.
[0041] The equipotential wide-face internal threaded plastic pipe fitting structure includes a plastic shell 1 and an equipotential insert 2. The plastic shell 1 is provided with a straight cylindrical part socket end 11, a curved arc part 12 and a threaded end 13 inlaid with the equipotential insert 2 in sequence. The equipotential insert 2 is provided with a partially exposed cylindrical end 21, an equipotential boss 22 and an equipotential connection screw hole 23.
[0042] The socket end 11 of the plastic shell 1 is cylindrical with an outer diameter of d and an inner diameter of D. According to product standards, the outer diameter d = 36mm and the inner diameter D = 25mm. It connects to the matching DN25 pipe and the bend arc portion 12. The inner cavity of the bend arc portion 12 is divided into a cylinder with a reduced diameter (D1) of 20mm to 24mm. The outer radius of the bend arc portion 12 is R, set to R = 36mm, which is not less than the radius of the connected socket. The outer diameter of end 11 is d; the inner radius of the curved portion 12 is R1, set to R1 = 29mm, which is not less than the inner diameter D1 of the connected end portion; the inner cavity channel of the threaded end 13 is a cylinder with an inner diameter of D2, set to D2 = 15mm according to product standards, and the connecting part is a pipe thread with a size of Rp1 / 2; the flow channel of the curved portion smoothly shrinks from a cylinder with an inner diameter of D1 to a cylinder with an inner diameter of D2, so that water can flow smoothly in the curved channel. At the same time, the height L1 of the threaded end 13 is set to be consistent with the height of the threaded end of the same type of traditional equipotential internal thread plastic pipe fitting, L1 = 42.5mm; the socket end 11 is set to transition tangentially with the curved portion 12, so that the length of the socket end 11 is L = 36mm, which is 2mm to 5mm longer than the length L0 of the socket end of the same type of traditional equipotential internal thread plastic pipe fitting, so that the lengths of the socket end 11 and the threaded end 13 are proportionate.
[0043] The cylindrical end 21 of the equipotential insert 2 is set as a cylinder with an outer diameter of d1, d1 = 37mm, which is 8mm larger than that of the traditional equipotential insert of the same model, realizing a 2-fold widening of the thread end face between its outer circle and the connecting pipe thread Rp; the exposed part after it is embedded in the plastic shell 1 has a length of L2, L2 = 4mm, making the reinforcement of the insert end strength visually apparent. The equipotential boss 22 of the equipotential insert 2 is embedded in the plastic shell 1 to form an island, penetrating to the outer wall of the plastic shell 1. The closest distance to the periphery of the plastic shell 1 is the distance A from the end face of its threaded end 13, A = 3mm, so that after injection molding and cooling, it forms a small closed-loop gap with the plastic shell 1, avoiding the visual perception of leakage; the equipotential boss 22 can be a trapezoid with its long base facing the end face of the equipotential insert 2, with a height of B, B = 8mm. An equipotential bonding screw hole 23 is provided at the center of the equipotential boss 22. The screw hole size is M, and it is designed as a standard internal thread M4, so as to connect with the building equipotential device after subsequent pipe installation.
[0044] The cylindrical end 21 of the equipotential insert 2 has a rectangular groove 24 with a partitioning function formed on its inner side. At least one narrow groove 25 and a dovetail groove 26 are provided on the central cylinder where the equipotential boss 22 is located. The tail end has a radial single-sided wedge groove 27, an inner cavity channel positioning hole 28 of the threaded end 13, and a circumferentially distributed protrusion 29 at the tail end. The surface of the insert into the plastic is smoothed by sandblasting or other cutting processes to increase the bonding effect with the plastic and increase the anti-leakage function.
[0045] Specifically, the cylindrical end 21 has a length of L3, L3 = 5mm, with a portion of its length embedded inside the plastic housing 1. The length of this embedded portion is L3 - L2 = 1mm. The rectangular groove 24 forms a partition at the point where the equipotential boss 22 extends to the cylindrical end 21. The partition width E is consistent with the width of the long trapezoidal side of the equipotential boss 22, E = 9mm. It can be hot-forged in one step and demolded axially toward the cylindrical end 21. Its minor diameter is consistent with the outer diameter d2 of the central cylinder with a draft angle, d2 = 26mm. Its depth is C1, C1 = 3mm, and its width is E1, E1 = 3.5mm, ensuring that the cylindrical end 21 has sufficient injection molding resistance.
[0046] A narrow groove 25 with a width of E2 and a depth of C2 is provided on both the front and rear sides of the equipotential boss 22. To maintain the anti-leakage effect, E2 ≤ 2.0 mm and C2 = 1.2 mm. After injection molding, the rectangular groove 24 and the narrow groove 25 on the front side of the equipotential boss 22 are embedded into the plastic shell 1 with the lower part of the cylindrical end 21, forming a plastic and metal interlocking structure that achieves excellent composite surface anti-leakage function.
[0047] The dovetail groove 26 is located on the outer side of the tail end of the central cylinder, with an opening width E3 = 2.5 mm, a dovetail angle a = 20°, and a groove depth consistent with the groove depth C2 of the narrow groove 25.
[0048] The single-sided wedge groove 27 is located on the inner side of the tail end of the equipotential insert 2, between the positioning hole 28 with an inner diameter of D2 and the injection channel of the single-sided wedge groove 27 with an inner diameter of D3. The thickness of the injection channel is (D3-D2) / 2 = 1.5mm, the groove depth is C3 = 1.2mm, the opening width is E4 = 2.5mm, and the single-sided wedge angle a1 on both sides is 20°. The dovetail angle a and the wedge angle a1 of the dovetail groove 26 and the single-sided wedge groove 27 make the plastic body with large shrinkage fit more tightly against the dovetail surface and the wedge surface when it cools and shrinks. Combined with the narrow groove 25 on the rear side of the equipotential boss 22, it forms the first layer of plastic and metal concave-convex structure that is the source of leakage after injection molding, realizing excellent composite surface anti-leakage function.
[0049] The protruding claw 29 is located at the tail end of the equipotential insert 2, with four or more evenly distributed around its circumference and a height L4 = 2.5 mm. Its outer side can be designed as a cylinder with the same outer diameter d2 as the central cylinder with a draft angle, and its inner side can be designed as a cylinder with an inner diameter D4 coaxial with the outer side. The thickness of the inner and outer sides is (d2-D4) / 2 = 2.5 mm. Its left and right sides can be designed as parallel surfaces with a width F, or as tangents perpendicular to the outer circle, forming an approximate trapezoid with inner and outer arcs, and a center width of F, with a width F = 4.0 mm. The protruding claw 29, together with the equipotential boss 22 and the rectangular groove 24, forms a combined circumferential barrier when embedded in the plastic pipe body, achieving a stronger anti-torsion function and further ensuring the anti-leakage function of the two anti-leakage grooves combined before and after the equipotential boss 22.
[0050] It will be apparent to those skilled in the art that this invention is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of this invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within this invention. No reference numerals in the claims should be construed as limiting the scope of the claims.
Claims
1. An equipotential wide-face internally threaded plastic pipe fitting, characterized in that, The device includes a plastic shell, which sequentially comprises a straight cylindrical portion with a socket end, a curved portion that transitions tangentially to the socket end, and a threaded end. The threaded end is used to embed an equipotential insert. The inner cavity of the socket end connects to the opening of the curved portion, which is divided into a cylinder with a reduced diameter of D1. The inner radius of the curved portion is R1, where R1 ≥ D1. The inner cavity channel of the threaded end is a cylinder with an inner diameter of D2. The flow channel of the curved portion smoothly narrows from a cylinder with an inner diameter of D1 to a cylinder with an inner diameter of D2, allowing water to flow smoothly within the curved channel.
2. The equipotential wide-face internally threaded plastic pipe fitting as described in claim 1, characterized in that, The socket end is a cylinder with an outer diameter of d and an inner diameter of D, connecting to the matching pipe and the curved section; the outer radius of the curved section is R, where R ≥ d.
3. An insert structure, compatible with the equipotential wide-face internally threaded plastic tubular fitting of claim 1 or 2, characterized in that, It includes an equipotential insert that is embedded and connected to a plastic housing, comprising a partially exposed cylindrical end, an equipotential boss with an embedded threaded end, and an equipotential connection screw hole.
4. The insert structure as described in claim 3, characterized in that, The equipotential insert has an equipotential boss embedded in the plastic shell to form an island, extending through the outer wall of the plastic shell. The closest distance between the insert and the periphery of the plastic shell is A, which is the distance from the end face of the threaded end. A ≥ 2 mm, so that a small closed-loop gap is formed between the insert and the plastic shell after injection molding and cooling. An equipotential connection screw hole is provided in the center of the equipotential boss to connect the insert to the building equipotential device after subsequent pipe installation.
5. The insert structure as described in claim 3, characterized in that, The cylindrical end of the equipotential insert is set as a cylinder with an outer diameter of d1. The outer diameter d1 dimension ensures that the outer circle and the threaded end face connected to the threaded end are widened by more than 1.5 times. The exposed part of the cylindrical end after being embedded in the plastic shell has a length of L2, which is 3mm to 5mm, to improve the strength of the insert opening.
6. The insert structure as described in claim 4, characterized in that, A rectangular groove with a partitioning function is formed on the inner side of the cylindrical end. At least one narrow groove and a dovetail groove, a radial single-sided wedge groove at the tail end, an inner cavity channel positioning hole at the threaded end, and a circumferentially distributed protrusion at the tail end are formed on the outer circle of the central cylinder where the equipotential boss is located.
7. The insert structure as described in claim 6, characterized in that, The rectangular groove forms a partition at the end of the cylindrical part where the equipotential boss extends; a narrow groove is provided on each side of the equipotential boss. After injection molding, the rectangular groove and the narrow groove on the front side of the equipotential boss are embedded into the plastic shell with the lower part of the cylindrical end to form a plastic and metal concave-convex structure, which realizes excellent composite surface anti-leakage function.
8. The insert structure as described in claim 7, characterized in that, The dovetail groove is located on the outer side of the central cylindrical end, with its depth consistent with that of the narrow groove. The single-sided wedge groove is located on the inner side of the equipotential insert end, between the positioning hole with an inner diameter of D2 and the injection channel of the single-sided wedge groove with an inner diameter of D3. The injection channel thickness (D3-D2) / 2 ≥ 0.5 mm, the groove depth C3 ≥ 1.2 mm, the opening width E4 ≥ 2 mm, and the single-sided wedge angle a1 ≥ 15°. The dovetail angle a and wedge angle a1 of the dovetail groove and the single-sided wedge groove improve the fit of the plastic body with large shrinkage during cooling and shrinkage. Combined with the narrow groove on the rear side of the equipotential boss, it forms the first layer of interlocking plastic and metal structure that is the source of leakage after injection molding, achieving excellent composite surface anti-leakage function.
9. The insert structure as described in claim 6, characterized in that, The protruding claw is located at the tail end of the equipotential insert, with 4 or more circumferentially distributed and a height L4≥2.0mm. The protruding claw, the equipotential boss, and the rectangular groove are embedded in the plastic tube body to form a combined circumferential barrier, further enhancing the anti-torsion function.
10. The insert structure as described in claim 6, characterized in that, The equipotential boss is a trapezoid with its long base facing the end face of the equipotential insert, and its height is B, where B ≥ 6 mm; wherein, the partition width E of the rectangular groove is consistent with the width of the long side of the trapezoid of the equipotential boss.