A pre-embedded part positioning mechanism

Abstract

The utility model provides a kind of preformed part positioning mechanism, belong to positioning mechanism technical field, the preformed part positioning mechanism includes preformed part body, positioning sleeve and anti-rotation key;The positioning sleeve is the tubular structure of two ends opening, its inner wall is formed with the non-circular groove extending along the axial direction;The preformed part body is the columnar structure, its outer wall is formed with the protruding key matched with the shape of the non-circular groove;The protruding key extends along the axial direction and is embedded in the non-circular groove, forms keyway cooperation structure;The anti-rotation key is the wedge-shaped block of independent setting, its cross-sectional shape is adapted to the remaining space of the non-circular groove, and is embedded in the non-circular groove tightly, to limit the rotation degree of freedom of the preformed part body relative to the positioning sleeve, solve how in the whole process of concrete pouring and hardening, to one-time completely eliminate preformed part rotation degree of freedom and long-term keep direction stable with pure mechanical construction.

Description

Technical Field

[0001] The utility model belongs to the technical field of positioning mechanisms, and specifically relates to an embedded part positioning mechanism. Background Art

[0002] An embedded part positioning mechanism is a pre-installed component for achieving reliable connection with post-installed equipment, steel structure nodes or electromechanical supports in concrete structures. Its function is to accurately and stably reserve the "connection interface" inside concrete during the pouring stage, and after the main structure is completed in the later stage, external loads are transferred to the main structure through bolts, clamps or adapter plates matched with the embedded part. It can be seen that the embedded part needs to bear static load, dynamic load and fatigue load in the final service stage, and must also keep its spatial coordinates and posture completely unchanged in unset concrete. Most traditional methods use a circular pipe or circular sleeve as the positioning carrier, several sections of short steel bars are welded at intervals on the outer wall as "anchor legs", and threads are machined inside the sleeve or a smooth circular hole is reserved; during construction, workers rely on hand-held simple supports or iron wire binding to fix the circular sleeve on the reinforcement cage, and then overall pouring is performed. The advantage of the cylindrical shape is that it is easy to process and there is no need to distinguish the direction when inserting into the reinforcement cage. However, it is precisely this "isotropic" characteristic that makes it extremely prone to "following rotation" during the flow of plastic concrete and the insertion and pulling out of the vibrator—that is, the sleeve generates micro-rotation along with the vibrator flow field. The direct consequence of rotation is that the direction of the internal thread or smooth hole becomes uncontrollable. When subsequent equipment base bolts must be inserted in a specific orientation, secondary reaming, additional welding of backing plates or even re-drilling for post-embedded anchor parts are often required on site, which not only damages the structural integrity, but also increases the hidden dangers of leakage and corrosion; if the embedded part is used to connect prefabricated wall panels or curtain wall hangers, direction deviation will also lead to accumulated problems such as uneven appearance joints and increased assembly stress. In addition, the contact surface between the circular sleeve and concrete is mainly a smooth cylindrical surface, with a small bonding area and weak tangential shear resistance. Micro-gaps are prone to appear under the repeated action of power equipment or temperature, and the gaps further weaken the anti-rotation and anti-pullout performance, forming a vicious cycle. To suppress rotation, construction sites often adopt measures such as lengthening the sleeve, thickening the anchor legs, increasing the density of binding iron wires or spot-welding positioning plates. However, these measures not only consume labor, but also concentrate stress on the welding spots and binding points, resulting in local deformation of the sleeve, burn of the galvanized layer or incomplete concrete pouring, and ultimately it is still difficult to completely eliminate direction drift. Summary of the Utility Model

[0003] In view of the above, the embedded part positioning mechanism provided by the present utility model solves the problem of how to completely eliminate the rotational freedom of the embedded part at one time through a pure mechanical structure and maintain directional stability for a long time during the whole process of concrete pouring and hardening.

[0004] The present utility model is implemented as follows:

[0005] This utility model provides a pre-embedded part positioning mechanism, comprising a pre-embedded part body, a positioning sleeve, and an anti-rotation key; the positioning sleeve is a cylindrical structure with openings at both ends, and its inner wall has a non-circular groove extending axially; the pre-embedded part body is a columnar structure, and its outer wall has a convex key that matches the shape of the non-circular groove; the convex key extends axially and is embedded in the non-circular groove to form a keyway fit structure; the anti-rotation key is an independently set wedge-shaped block, the cross-sectional shape of which is adapted to the remaining space of the non-circular groove, and is tightly embedded in the non-circular groove to restrict the rotational freedom of the pre-embedded part body relative to the positioning sleeve.

[0006] The technical effects of the embedded part positioning mechanism provided by this utility model are as follows: Through the key-groove-wedge composite structure jointly formed by the embedded part body, the positioning sleeve and the independent wedge-shaped anti-rotation key, during the impact and vibration of concrete pouring, the non-circular groove and the circumferential rigid engagement of the convex key are used to block large-angle rotation, and the lateral tightening of the wedge-shaped anti-rotation key is used to eliminate the gap in the key-groove manufacturing. This ensures that the orientation of the embedded part is always locked throughout the entire cycle of slurry flow and hardening, and completely solves the problem that traditional round sleeve embedded parts are prone to "following the rotation" and causing difficulties in the alignment of subsequent equipment.

[0007] Based on the above technical solution, the embedded part positioning mechanism of this utility model can be further improved as follows:

[0008] The non-circular groove has a cross-sectional profile consisting of at least one arc segment and at least one straight line segment connected together. The curvature center of the arc segment coincides with the central axis of the positioning sleeve, and the straight line segment smoothly transitions to the arc segment.

[0009] The beneficial effects of adopting the above-mentioned improved scheme are as follows: After adopting a non-circular contour with smooth connection between arc and straight line segments, the inner wall of the positioning sleeve maintains strong circumferential constraint on the convex key, while the straight line segment provides a flat bearing surface, which can quickly convert the rotational torque into radial compressive stress and homogenize it to the sleeve wall, avoiding stress concentration that causes local cracking. Thus, a simple geometric transformation can be used to balance anti-rotation strength and mold processing convenience.

[0010] Furthermore, the cross-sectional profile of the convex key is mirror-symmetrical to the cross-sectional profile of the non-circular groove, and the radial thickness of the convex key remains constant along the axial direction.

[0011] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the convex key and the non-circular groove are mirror symmetrical and extend with equal thickness, so that the embedded part forms a "self-centering" guide when it is pressed in, and the on-site workers can insert it into place in one go without additional measuring tools; the equal thickness section also ensures that the load-bearing capacity of each section of the key is consistent, eliminating the risk of shearing and breakage caused by sudden changes in thickness, and improving the efficiency and safety of high-altitude or narrow space operations.

[0012] Furthermore, the anti-rotary key wedge-shaped block has a tapered end that gradually thins toward the embedded part body, and the surface of the tapered end is formed with a serrated anti-slip texture.

[0013] The beneficial effects of adopting the above-mentioned improved scheme are as follows: After the anti-rotary key is provided with a conical wedge with serrated texture, the wedge gradually squeezes and bites the micro-protrusions on the groove wall during the hammering and embedding process, forming an irreversible mechanical interlock. Even if the concrete solidifies and shrinks, causing the sleeve wall to rebound slightly, the serrations can still hook the groove wall and continuously provide anti-loosening torque, achieving the reverse self-stabilizing effect of "the more it vibrates, the tighter it becomes".

[0014] Furthermore, the outer wall of the positioning sleeve is formed with spiral raised ribs, and the pitch of the raised ribs gradually decreases from top to bottom along the axial direction.

[0015] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: the outer wall of the positioning sleeve adopts spiral raised ribs with a pitch decreasing from top to bottom, so that the resistance increases when the sleeve is inserted into the concrete, making it easy to sink and correct in the early stage, and automatically braking when the resistance increases sharply in the later stage, preventing the pre-embedded elevation from exceeding the tolerance due to excessive sinking; at the same time, the spiral ribs also form a thread engagement with the hardened concrete, which has the dual anchoring effect of vertical pull-out resistance and circumferential anti-rotation.

[0016] Furthermore, the bottom end of the embedded part body is formed with a radially outwardly expanding trumpet-shaped anchoring part, and an annular groove is formed on the outer surface of the anchoring part, and an elastic sealing ring is embedded in the annular groove.

[0017] The beneficial effects of adopting the above-mentioned improved scheme are as follows: the trumpet-shaped anchoring part at the bottom of the embedded part, together with the elastic sealing ring in the annular groove, uses the radial expansion tendency of the trumpet opening to press the sealing ring against the surrounding grout before the concrete initially sets. This not only prevents the grout from climbing up the outer wall of the embedded part and contaminating the internal threads, but also uses the elastic recoil of the sealing ring to form micro-prestress after hardening, so that the anchoring part is always in close contact with the concrete, eliminating the anchoring loosening caused by micro-cracks in the later stage.

[0018] Furthermore, the bottom of the non-circular groove is formed with an axially penetrating exhaust channel, and the cross-sectional area of ​​the exhaust channel gradually increases from top to bottom along the axial direction.

[0019] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: After adding an exhaust channel that gradually expands from top to bottom at the bottom of the non-circular groove, the air trapped in the groove can escape quickly along the gradually expanding channel when the convex key is pressed in, avoiding air resistance that causes the key to not be inserted properly; the gradually expanding shape of the exhaust channel also causes the high-speed flowing air to generate a suction effect, which drives the scattered concrete particles in the groove to be discharged downwards, keeping the key-groove mating surface clean and ensuring that the anti-rotation accuracy does not fail due to residue.

[0020] Furthermore, the sidewall of the convex key is formed with an arc-shaped recess, and the arc-shaped recess is filled with a buffer layer made of a water-swellable material.

[0021] Optionally, the buffer layer is a bentonite and rubber composite expandable body, the composition of which by volume includes: 60-70 parts of sodium bentonite, 25-30 parts of styrene-butadiene rubber latex, 3-5 parts of cellulose ether water-retaining agent, and a trace amount of crosslinking agent; the composite body is plastic in the dry state, which is sufficient to absorb the slight rotational displacement between the embedded part and the positioning sleeve before the concrete hardens, and forms a damping interface after hardening to prevent loosening caused by subsequent micro-vibration.

[0022] Furthermore, the top of the positioning sleeve is formed with a radially outwardly turned limiting flange, and the lower surface of the limiting flange is formed with serrated interlocking teeth, the tips of which are inclined toward the central axis of the positioning sleeve.

[0023] The beneficial effects of the above-mentioned improvement scheme are as follows: The lower surface of the outward-curving limiting flange at the top of the positioning sleeve is provided with serrated interlocking teeth that are inclined towards the center. When the water seepage layer on the concrete surface has not yet hardened, the flange can press down to cut the inclined teeth into the seepage layer. After the seepage layer hardens, it forms a barbed anchor, which not only prevents the sleeve from sinking further, but also converts the external upward pulling force into a radial inward contraction force through the inclined direction of the teeth, so that the positioning sleeve and the concrete interface are pulled tighter and tighter, further improving the overall anti-rotation and anti-pull composite performance.

[0024] Furthermore, the anti-rotation key wedge block is composed of two symmetrically arranged semi-wedge blocks, which are connected by an elastic connector. In its natural state, the elastic connector keeps the two semi-wedge blocks away from each other.

[0025] The elastic connector is an "Ω-shaped leaf spring integrated bridging piece", and its arrangement is as follows:

[0026] Shape: The middle part is a 180° circular arch, and the two ends are equipped with barbed anchor feet;

[0027] The barbed anchors at both ends of the leaf spring are pressed into the dovetail grooves reserved on the opposite sides of the two wedge blocks to form an interference fit. In its natural state, the leaf spring arches outward, making the total thickness of the two wedge blocks greater than the width of the non-circular groove of the positioning sleeve. During installation, the leaf spring can be inserted by compression. After insertion, the leaf spring rebounds and continuously provides lateral clamping force, so that the anti-rotation key and the groove wall maintain a gapless contact, thereby eliminating the relative rotation gap between the key and groove caused by the impact of concrete pouring.

[0028] Compared with existing technologies, the beneficial effects of the embedded part positioning mechanism provided by this utility model are as follows: This utility model, without relying on sensors, power supplies, or control algorithms, eliminates rotational freedom at its source by redesigning the shape and connection relationship of the embedded part body, positioning sleeve, and anti-rotation key. This ensures the embedded part maintains its initial orientation during the concrete plastic stage, hardening stage, and long-term service stage. Firstly, the rigid engagement of the non-circular groove and the convex key immediately converts any potential torque into radial compressive stress, which is then dispersed throughout the circumference of the positioning sleeve via a smooth transition contour, preventing stress concentration and subsequent sleeve wall cracking. Simultaneously, because the keyway fit itself has a clear directional characteristic, workers can insert it into place in one go without a protractor, simultaneously improving construction efficiency and finished product qualification rate. Secondly, the independent wedge-shaped anti-rotation key gradually tightens the remaining gap in the keyway during the hammering and embedding process. Its serrated end bites the groove wall, forming an irreversible mechanical interlock, making "the more you vibrate, the tighter it gets" a reality. Even if the concrete solidification shrinkage causes slight rebound of the sleeve wall, the wedge structure can still automatically compensate and maintain the lateral clamping force, thus continuously providing anti-loosening torque throughout the entire service life. The spiral ribs with decreasing pitch on the outer wall of the positioning sleeve give the sleeve a "easy to insert, difficult to insert" characteristic. It is easy to correct the height in the early stage, and automatically brakes when the resistance increases sharply in the later stage to prevent the elevation from exceeding the tolerance. At the same time, the spiral shape forms a threaded engagement with the hardened concrete, combining vertical pull-out resistance and circumferential anti-rotation resistance into one, achieving high load-bearing capacity without additional anchor feet. The trumpet-shaped anchoring part at the bottom of the embedded part works in conjunction with the elastic sealing ring to block the grout from climbing up before initial setting and protect the internal thread from contamination. After hardening, the elastic retraction of the sealing ring generates micro-prestress, ensuring that the anchoring part is always in close contact with the concrete, eliminating the anchoring loosening caused by micro-cracks in the later stage. The non-circular groove's gradually expanding exhaust channel utilizes aerodynamic principles to create a suction effect the instant the convex key is pressed in, automatically removing residue and air bubbles from the groove. This ensures a clean and tight fit between the key and groove, preventing the anti-rotation precision from being reduced by impurities on-site. The bentonite-rubber composite expander within the arc-shaped recess on the convex key's sidewall undergoes uniform micro-expansion in a humid environment. This automatically compensates for manufacturing errors and temperature gaps, while also absorbing vibration energy during equipment operation due to its viscoelastic properties, preventing structural fatigue caused by long-term micro-vibrations. Its arc-shaped recess layout aligns the expansion pressure with the principal stress direction of the key, without additionally weakening the key's strength. The inclined serrations on the lower surface of the outward-flaring limiting flange at the top of the positioning sleeve cut into the concrete surface before the water layer hardens. After hardening, they form barbs, converting the external upward pulling force into a radial inward contraction force, tightening the positioning sleeve against the concrete interface and further enhancing the composite resistance. Finally, the two wedge-shaped blocks, bridged by Ω-shaped leaf springs, form an "elastic assembly" for the anti-rotation key. Before installation, the leaf springs naturally spring outward, making the total thickness slightly greater than the groove width. After being hammered into place, it can achieve zero-gap self-locking and compensate for the shrinkage or temperature change of the concrete in real time, maintaining a constant lateral clamping force. At the same time, the disassembled structure facilitates later maintenance and replacement without damaging the existing concrete. Attached Figure Description

[0029] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is an example diagram of a pre-embedded part positioning mechanism;

[0031] Figure 2 This is a top view of a pre-embedded part positioning mechanism;

[0032] Figure 3 A perspective view of an embedded part positioning mechanism;

[0033] The attached diagram lists the components represented by each number as follows:

[0034] 10. Embedded part body; 11. Protruding key; 20. Positioning sleeve; 21. Non-circular groove; 30. Anti-rotation key. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings.

[0036] like Figures 1-3 The diagram shown is an example of a pre-embedded part positioning mechanism provided by this utility model, including a pre-embedded part body 10, a positioning sleeve 20, and an anti-rotation key 30; the positioning sleeve 20 is a cylindrical structure with openings at both ends, and its inner wall has a non-circular groove 21 extending axially; the pre-embedded part body 10 is a columnar structure, and its outer wall has a convex key 11 that matches the shape of the non-circular groove 21; the convex key 11 extends axially and is embedded in the non-circular groove 21 to form a keyway fit structure; the anti-rotation key 30 is an independently set wedge-shaped block, the cross-sectional shape of which is adapted to the remaining space of the non-circular groove 21, and is tightly embedded in the non-circular groove 21 to restrict the rotational freedom of the pre-embedded part body 10 relative to the positioning sleeve 20.

[0037] When using it, first place the positioning sleeve in the steel cage, so that the limiting flange is against the bottom surface of the template, with the end with the densest spiral ribs facing down.

[0038] Insert the pre-embedded part into the pen holder from top to bottom, align the convex key with the groove and slowly slide it to the bottom. At this time, the edge of the anchoring part at the bottom of the chopstick is basically flush with the bottom of the pen holder, and the soft clay ear leaves a "uniform slit" between itself and the groove wall.

[0039] Take the anti-rotary key and tap it in along the narrow seam:

[0040] If it is a single wedge, with the serrated side facing up and the thicker end first, tap it to tighten it until it can no longer be tapped; if it is a split wedge, first pinch the leaf spring to bring the two halves closer together, put them into the narrow gap and then release, the Ω-shaped leaf spring will automatically open, and the two halves will be firmly pressed against the side wall of the groove.

[0041] After the concrete is poured, the outer spiral rib of the positioning sleeve engages with the concrete, the limiting flange is wrapped by the concrete into a "barb", and the body of the embedded part is locked by the key and wedge and cannot rotate; the rubber ring in the anchoring part is squeezed and rebounded by the concrete, forming a pre-pressure seal; the crescent-shaped soft mud absorbs water and expands slightly, filling any possible micron-level gaps.

[0042] After demolding, the top surface of the embedded part body reveals a clean threaded hole, and its direction remains consistent with the factory orientation of the template reference edge, requiring no secondary correction.

[0043] In the above technical solution, the cross-sectional profile of the non-circular groove 21 is formed by connecting at least one arc segment and at least one straight segment. The curvature center of the arc coincides with the central axis of the positioning sleeve 20, and the straight segment is smoothly connected to the arc segment.

[0044] Furthermore, in the above technical solution, the cross-sectional profile of the convex key 11 is mirror-symmetrically arranged with the cross-sectional profile of the non-circular groove 21, and the radial thickness of the convex key 11 remains constant along the axial direction.

[0045] Furthermore, in the above technical solution, the wedge-shaped block of the anti-rotary key 30 has a tapered end that gradually thins towards the embedded part body 10, and the surface of the tapered end is formed with a serrated anti-slip texture.

[0046] Furthermore, in the above technical solution, the outer wall of the positioning sleeve 20 is formed with spiral raised ribs, and the pitch of the raised ribs gradually decreases from top to bottom along the axial direction.

[0047] Furthermore, in the above technical solution, the bottom end of the embedded part body 10 is formed with a radially outwardly expanding trumpet-shaped anchoring part, and an annular groove is formed on the outer surface of the anchoring part, with an elastic sealing ring embedded in the annular groove.

[0048] Furthermore, in the above technical solution, the bottom of the non-circular groove 21 is formed with an axially penetrating exhaust channel, and the cross-sectional area of ​​the exhaust channel gradually increases from top to bottom along the axial direction.

[0049] Furthermore, in the above technical solution, the sidewall of the convex key 11 is formed with an arc-shaped recess, and the arc-shaped recess is filled with a buffer layer made of a water-swellable material.

[0050] Furthermore, in the above technical solution, the top of the positioning sleeve 20 is formed with a radially outwardly flared limiting flange, and the lower surface of the limiting flange is formed with serrated interlocking teeth, the top of the interlocking teeth being inclined toward the central axis of the positioning sleeve 20.

[0051] Furthermore, in the above technical solution, the wedge-shaped block of the anti-rotary key 30 is composed of two symmetrically arranged semi-wedge blocks, which are connected by an elastic connector. In its natural state, the elastic connector keeps the two semi-wedge blocks away from each other.

[0052] Example 1: Pre-embedded positioning of overhead pipeline supports in urban underground utility tunnels: During the construction of the concrete utility tunnel roof slab with a cross-sectional clearance of 3.5m, a support suspension line perpendicular to the tunnel axis needs to be reserved every 6m for later installation of fire protection, power, and communication cable trays. Traditional round sleeve embedded parts are prone to rotation during roof slab pouring due to the lateral movement of the vibrator, resulting in misalignment between the internal threaded hole and the cable tray hanger, requiring high-altitude hole enlargement later, which poses a high operational risk. This utility model adopts the following: The positioning sleeve uses a rectangular-circular arc composite section, with four spiral ribs of decreasing pitch cast integrally on the outer wall; the embedded part body is a high-strength alloy column, with a rectangular convex key milled on the outer periphery that is completely conjugate to the inner cavity of the sleeve; the anti-rotation key is a single integral wedge-shaped cast steel piece with circumferential serrations machined at the end. During construction, workers first spot weld the positioning sleeve to the cross intersection of the top-layer steel mesh, with the sleeve opening flush with the bottom surface of the formwork. Then, the embedded part with the raised key is inserted from above and gently tapped into place. Next, the integral wedge-shaped anti-rotation key is driven into the remaining space of the keyway along the reserved notch until the tapping sound becomes solid. During the concrete descent, the spiral rib guides the sleeve to sink and correct itself, and later, as the resistance increases, it automatically locks the elevation. The serrated teeth of the wedge-shaped key bite into the sleeve wall, and repeated insertion and removal of the vibrator cannot cause the embedded part to rotate at all. After curing, the cable tray hanger can be directly screwed into the internal thread of the embedded part, and the hole position and the alignment with the support line are visually identifiable as perfectly aligned. This embodiment fully utilizes the combination of spiral ribs and integral wedge keys to achieve zero rotation and zero sinking in environments with high ceilings, unilateral operation, and intense vibration, making it suitable for various long-distance linear pipe gallery top suspension systems.

[0053] Example 2: Pre-embedded flange connection for wind turbine tower portal opening in high-altitude wind farms: For wind farms at an altitude of 3,000 meters, a set of flange connection seats needs to be embedded on each side of the portal opening on the outer wall of the tower foundation ring to fix the steel beams of the later maintenance platform. The foundation ring concrete is poured continuously in one go, with a large drop, low temperature, and long vibration time. Ordinary round pipe embedded parts often deflect due to low-temperature shrinkage and the superposition of vibration flow fields, causing the flange face to fail to fit with the angle steel of the steel beam installation. On-site heating and correction are necessary, which is time-consuming and labor-intensive. This example adopts a split elastic anti-rotation key scheme: the positioning sleeve maintains a rectangular-circular arc composite inner cavity, and the outer wall spiral rib remains unchanged; an arc-shaped recess is added to the side wall of the convex key of the embedded part body and filled with a bentonite-rubber composite buffer layer; the anti-rotation key is changed to two symmetrical wedge-shaped blocks, bridged in the middle by an Ω-shaped leaf spring. During construction, the positioning sleeve is first welded to the outer layer of reinforcing steel in the foundation ring, with the sleeve opening tightly against the steel formwork. After inserting the embedded part body, the two wedge-shaped blocks, along with the leaf spring, are pushed into the keyway. The leaf spring's arch height is compressed and rebounds, immediately pressing against the groove wall. In low-temperature environments, as concrete slowly shrinks, the leaf spring continuously extends to compensate for the gap, and the buffer layer slightly expands to fill the micropores in the keyway, preventing rotational loosening caused by cold contraction. After curing, the direction of the flange connection seat bolt holes is strictly parallel to the center line of the doorway, and the steel beam is successfully bolted on the first attempt, without the need for flame alignment. This embodiment, through "elastic split key + buffer layer" adaptive low-temperature shrinkage, is suitable for direction-sensitive embedded parts in wind power foundation rings or other large-volume concrete structures at high altitudes, with large temperature differences, and strong vibration.

[0054] Specifically, the principle of this invention is as follows: This invention upgrades the single mechanism of traditional circular sleeve positioning, which relies solely on friction to resist rotation, into a multi-coupling system of "keyway engagement—wedge clamping—elastic compensation—threaded anchoring—barb limiting." First, the conjugate profile formed by the non-circular groove and the convex key is mathematically an "equidistant conformal mapping." Any relative rotation will cause interference lifting of the key-groove wall, thus converting the rotational degree of freedom into radial compressive work. Due to the continuous and smooth profile, the compressive stress is evenly distributed throughout the mating section, avoiding stress peaks caused by sharp angle abrupt changes. Second, the independent wedge-shaped anti-rotation key introduces the principle of "inclined self-locking": During the hammering embedding stage, the lateral component force generated by the wedge surface and the elastic restoring force of the sleeve wall form positive feedback, making the lateral clamping force greater the deeper the key goes; once the concrete begins to harden, the sleeve wall slightly rebounds, and the self-locking condition determined by the wedge angle and the coefficient of friction is met, preventing the key from retracting on its own. This converts the "instantaneous hammering force" into "persistent static friction force," achieving one-time embedding and lifelong clamping. The spiral ribs on the outer wall of the positioning sleeve utilize the principle of "decreasing spiral angle" to make the vertical resistance experienced by the sleeve increase non-linearly during insertion. The resistance is low in the early, small-pitch section, facilitating attitude correction, while the resistance is high in the later, large-pitch section, providing automatic positioning. Simultaneously, the spiral shape creates an "internal thread" effect in the concrete, transforming the shear failure mode of a traditional smooth cylindrical surface into a compression-shear composite bearing mode of a spiral surface, significantly improving the synergistic efficiency of pull-out and rotation resistance. The trumpet-shaped anchor at the bottom of the embedded part and the sealing ring employ the "prestress-sealing" coupling concept: the trumpet expands outward during the plastic stage of the concrete, compressing the sealing ring to fill the micropores and forming an initial seal; after hardening, the sealing ring elastically retracts, applying radial compressive stress to the concrete, placing the interface in a "compression-interlocking" state, blocking the propagation path of micro-cracks, and thus sealing potential water vapor erosion channels in advance. The gradually expanding exhaust channel at the bottom of the non-circular groove utilizes the "Venturi suction" effect. When the convex key is pressed in at high speed, the air in the groove is forced through the expanding section, increasing the flow rate and decreasing the pressure, forming a local vacuum. This actively extracts residues and air bubbles, ensuring the cleanliness of the mating surfaces and avoiding stress concentration and increased gaps caused by impurities. The bentonite-rubber composite in the arc-shaped recess on the sidewall of the convex key plays a "humidity-stress" conversion role: the bentonite particles absorb water and expand, providing volume growth, while the rubber network provides elastic restraint. Together, they keep the expansion pressure within the range of "sufficient to fill the gap but insufficient to split the key." At the same time, the viscoelastic damping properties of the rubber convert external vibration energy into heat energy for dissipation, reducing the resonance amplification effect. The inclined saw teeth of the limiting flange at the top of the positioning sleeve use the principle of "inclined blade-barb". When the flange is pressed down, the saw teeth cut into the unhardened water layer. The inclination angle causes the tooth body to generate a radial inward contraction force when subjected to upward pulling force, so that the tooth tip is pulled deeper and deeper, forming a self-reinforcing barb. This process does not require additional adhesive materials and can achieve "mechanical rooting" solely by the hardening properties of concrete itself.Finally, the Ω-shaped leaf spring between the two wedge-shaped blocks transforms the "integral rigid key" into an "elastic combination key." The arched structure of the leaf spring stores elastic potential energy during compression and generates a continuous lateral thrust when released, ensuring that the anti-rotation key and the groove wall always maintain positive pressure. When the concrete undergoes slight deformation due to temperature or shrinkage, the leaf spring automatically adjusts the total thickness of the key body through elastic expansion and contraction, avoiding the risk of loosening or shearing caused by the "fixed interference fit" of the rigid key. At the same time, the split structure allows the key body to be removed separately for later maintenance without damaging the surrounding concrete.

Claims

1. A positioning mechanism for embedded parts, characterized in that, The device includes an embedded part body, a positioning sleeve, and an anti-rotation key. The positioning sleeve is a cylindrical structure with openings at both ends, and its inner wall has a non-circular groove extending axially. The embedded part body is a columnar structure, and its outer wall has a convex key that matches the shape of the non-circular groove. The convex key extends axially and is embedded in the non-circular groove to form a keyway fit structure. The anti-rotation key is an independently set wedge-shaped block, the cross-sectional shape of which is adapted to the remaining space of the non-circular groove, and is tightly embedded in the non-circular groove to restrict the rotational freedom of the embedded part body relative to the positioning sleeve.

2. The embedded part positioning mechanism according to claim 1, characterized in that, The cross-sectional profile of the non-circular groove is formed by connecting at least one arc segment and at least one straight line segment. The curvature center of the arc segment coincides with the central axis of the positioning sleeve, and the straight line segment smoothly transitions to the arc segment.

3. The embedded part positioning mechanism according to claim 2, characterized in that, The cross-sectional profile of the convex key is mirror-symmetrical to the cross-sectional profile of the non-circular groove, and the radial thickness of the convex key remains constant along the axial direction.

4. The embedded part positioning mechanism according to claim 3, characterized in that, The anti-rotary key wedge-shaped block has a tapered end that gradually thins toward the embedded part body, and the surface of the tapered end is formed with a serrated anti-slip texture.

5. The embedded part positioning mechanism according to claim 4, characterized in that, The outer wall of the positioning sleeve is formed with spiral raised ribs, and the pitch of the raised ribs gradually decreases from top to bottom along the axial direction.

6. The embedded part positioning mechanism according to claim 5, characterized in that, The bottom end of the embedded part body has a radially outward-expanding trumpet-shaped anchoring part, and the outer surface of the anchoring part has an annular groove, in which an elastic sealing ring is embedded.

7. The embedded part positioning mechanism according to claim 6, characterized in that, The bottom of the non-circular groove forms an axially penetrating exhaust channel, and the cross-sectional area of ​​the exhaust channel gradually increases from top to bottom along the axial direction.

8. The embedded part positioning mechanism according to claim 7, characterized in that, The sidewall of the convex key has an arc-shaped recess, which is filled with a buffer layer made of water-swellable material.

9. A pre-embedded part positioning mechanism according to claim 8, characterized in that, The top of the positioning sleeve has a radially outwardly turned limiting flange, and the lower surface of the limiting flange has serrated interlocking teeth, the tips of which are inclined toward the central axis of the positioning sleeve.

10. A pre-embedded part positioning mechanism according to claim 9, characterized in that, The anti-rotation key wedge block is composed of two symmetrically arranged semi-wedge blocks, which are connected by an elastic connector. In its natural state, the elastic connector keeps the two semi-wedge blocks away from each other.

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