Low-damping quick-screwing thread adjusting structure

Abstract

The invention discloses a low-damping quick-screwing thread adjusting structure which comprises a supporting assembly used for supporting an overall structure and connecting a denture column of oral cavity CBCT equipment; the spiral assembly is fixedly connected with the supporting assembly and used for driving the head clamp to achieve synchronous reverse movement. The spiral assembly comprises a transmission assembly structure which is fixed in the supporting assembly; the ear clip power assembly comprises a fixed part and a movable part, and the movable part is guided by the transmission assembly structure to achieve linear motion. Through a three-point fixing system formed by rigid locking of the jaw support mounting assembly and the denture column, synchronous reverse clamping of the double ear clips and integration of the shell part and the jaw support surface, six-degree-of-freedom full constraint of the head is achieved, and the influence of motion artifacts on head shadow measurement analysis is reduced.

Description

Technical Field

[0001] The invention relates to an adjustment structure, in particular to a low-damping fast spiral thread adjustment structure. Background Art

[0002] In the field of orthodontics, cone-beam computed tomography (CBCT) technology has become a core method for three-dimensional head and facial imaging. To achieve accurate orthodontic diagnosis and treatment planning, it is necessary to fix the patient's head during the scanning process and obtain quantifiable anatomical landmark data (such as the orbitoauricular plane angle and the nasion-premental distance). Existing technologies typically use a dental bracket combined with a head fixation fixture, but this has significant drawbacks in practical application.

[0003] Limitations of existing head fixation devices (1) Insufficient positioning stability Traditional fixtures often utilize a single-point jaw support coupled with an elastic ear clamp. This can easily cause slight head movement during scanning, leading to motion artifacts. In particular, when the ear clamp's clamping force is insufficient, it becomes difficult to maintain the three-dimensional coordinate stability of the ear canal area, impacting the accuracy of subsequent cephalometric analysis.

[0004] (2) Lack of integrated measurement benchmarks Existing devices typically lack integrated dimensional calibration mechanisms, forcing physicians to manually add a scale bar after scanning or rely on software-based calibration, leading to systematic errors in measurement results. Some attempts to attach a scale bar to the outside of the fixture are prone to projection distortion due to misalignment in mounting position or scanning angle.

[0005] (3) Defects in adjustment efficiency and comfort The ear clip spacing adjustment mechanism mostly uses gear rack or ordinary screw drive, which has some problems: High operational damping: Traditional threaded surfaces have high contact friction resistance, requiring medical staff to vigorously turn the knob to adjust, which is inefficient and can easily cause discomfort to patients; Asynchronous adjustment: Unilateral adjustment causes asymmetric force on the head, which may force the patient's head to tilt and disrupt the natural head position. Summary of the Invention

[0006] The object of the present invention is to provide a low-damping fast-screw thread adjustment structure to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solutions: A low-damping fast spiral thread adjustment structure, comprising: The support assembly is used to support the overall structure and connect the dental bracket of the oral CBCT equipment; the spiral assembly is fixedly connected to the support assembly and is used to drive the head clamp to achieve synchronous reverse movement; the spiral assembly includes: a transmission assembly structure fixed inside the support assembly; an ear clip power assembly, which includes a fixed part and a moving part, and the moving part is guided by the transmission assembly structure to achieve linear motion.

[0008] As a further solution of the present invention: the support assembly includes: an outer shell member, which covers the entire internal structure; a jaw support mounting assembly, which is fixed to the upper half of the inner part of the outer shell member and is used to connect the dental bracket column; a scale structure, which is integrally formed with the outer shell member and is arranged at its upper end, with a scale embedded inside.

[0009] As a further solution of the present invention: the jaw support mounting assembly includes: two mounting rod fixing plates, a mounting back plate, a fixing knob and a mounting rod; the mounting rod passes through the circular mounting holes of the mounting rod fixing plate and the mounting back plate, one end of which is connected to the fixing knob, and the other end is adapted to the bracket column mounting hole.

[0010] As a further solution of the present invention: the transmission assembly structure includes: a moving part positioning assembly, the bottom surface of which is provided with two sets of sliding guide grooves; ear clip fixing rod mounting positions, which are provided on the side surfaces at both ends of the moving part positioning assembly; and a fixed plate mounting hole, which is provided on the upper end surface of the moving part positioning assembly.

[0011] As a further solution of the present invention: the moving part of the ear clip power assembly includes: a transmission structure, including two sets of screw assemblies and a screw connection structure connecting the two; the end of the screw assembly is provided with an ear clip mounting part, and the outer wall is provided with a first threaded structure.

[0012] As a further solution of the present invention: the cross section of the first thread structure is arc-shaped, and the threads of the two sets of screw assemblies have opposite rotation directions.

[0013] As a further solution of the present invention: the moving part also includes: a moving part connecting component shell, which is sleeved on the outside of the screw component; a guide sliding component, which is arranged inside the moving part connecting component shell, and its inner wall is provided with a second thread structure with a rotation direction opposite to the first thread structure.

[0014] As a further solution of the present invention: the second thread structure and the first thread structure form a line contact pair: single-point contact is present on any cross section, forming continuous line contact between the convex ridge and the concave surface in three-dimensional space.

[0015] As a further solution of the present invention: a movable guide block is fixed at the bottom of the guide sliding assembly; The movable guide block is a columnar structure with two flat sides, adapted to the sliding guide groove to achieve linear guidance.

[0016] As a further solution of the present invention: the guide sliding component and the moving part connecting component shell are fixed through a limiting structure and a limiting mounting hole; the limiting structure can be elastically and telescopically installed in the waist-shaped mounting groove of the guide sliding component and locked by a spring and a snap mechanism.

[0017] As a further solution of the present invention: the scale of the scale structure is used to measure the distance and angle of the head and face landmarks.

[0018] As a further solution of the present invention: the ear clip spacing of the spiral assembly is adjusted by pulling the ear clips synchronously with both hands, driving the movable part to connect the assembly housing and the transmission structure to move relative to each other, and the reverse thread pair converts the linear input into synchronous rotation of the twin screws.

[0019] As a further solution of the present invention: the fixed part of the ear clip power assembly includes a bottom fixing plate of the moving part, which is fixed to the bottom of the transmission assembly structure by screws.

[0020] As a further solution of the present invention: the screw connection structure of the transmission structure is provided with a rotating bearing, the outer wall of which is interference fit with the inner wall of the transmission assembly structure.

[0021] Compared with the prior art, the present invention has the following beneficial effects: The three-point fixation system formed by the rigid locking of the jaw support mounting assembly and the bracket column, the synchronous reverse clamping of the two ear clamps, and the integration of the jaw support surface into the outer shell can achieve full six-degree-of-freedom constraint of the head and reduce the influence of motion artifacts on cephalometric analysis.

[0022] The linear contact pair consisting of an arc-shaped first thread and an opposite second thread reduces friction resistance. Combined with the interference support of the rotating bearing and the planar moving guide block and guide groove (low-friction pair), medical staff can complete full-stroke adjustment with one hand, thereby improving efficiency.

[0023] Based on the synchronous reverse transmission mechanism of the twin-screw components with opposite rotation directions and the rigid connection structure, the symmetry error of the ear clip spacing adjustment is small, no torsional torque input is applied to the patient's head during the adjustment process, the natural head position is maintained at a high rate, and the compensatory deviation of the temporomandibular joint caused by traditional unilateral adjustment is avoided. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of the structure of the thread adjustment structure of the low-damping fast spiral.

[0025] Figure 2 Another structural diagram of the thread adjustment structure of the low-damping fast spiral.

[0026] Figure 3 This is a schematic diagram of the structure of the thread adjustment structure of the low-damping fast spiral after removing the outer shell.

[0027] Figure 4 Exploded view of the thread adjustment structure of the low-damping quick screw.

[0028] Figure 5 This is a structural diagram of the transmission component structure in the thread adjustment structure of the low-damping fast spiral.

[0029] Figure 6 Schematic diagram of the structure of the spiral component in the thread adjustment structure of the low-damping fast spiral.

[0030] Figure 7 This is an exploded view of the spiral component.

[0031] Figure 8 This is the left side view of the spiral component.

[0032] Figure 9 This is a schematic diagram of the AA section of the left view of the spiral component.

[0033] Figure 10 This is an exploded view of the vertical direction of the thread adjustment structure of the low-damping fast screw.

[0034] Figure 11 This is a front view of the vertical exploded view of the thread adjustment structure of the low-damping fast screw.

[0035] Figure 12 This is the left side view of the vertical exploded view of the thread adjustment structure of the low-damping fast screw.

[0036] Figure 13 This is the vertical exploded view, left view and BB-direction cross-sectional view of the thread adjustment structure of the low-damping quick screw.

[0037] Figure 14 This is a schematic diagram of the transmission structure in the ear clip power assembly.

[0038] Figure 15 This is the left view of the transmission structure in the ear clip power assembly.

[0039] Figure 16 This is a cross-sectional view of the transmission structure in the ear clip power assembly along the CC direction.

[0040] Figure 17 Schematic diagram of the structure of the guide sliding component.

[0041] Figure 18 The left side view of the guide slide assembly.

[0042] Figure 19 It is a sectional view of the left side of the guide sliding assembly in the DD direction. DETAILED DESCRIPTION

[0043] The technical solution of this patent is further described in detail below in conjunction with specific implementation methods.

[0044] See also Figure 1-3 , a low-damping fast spiral thread adjustment structure, mainly composed of a support component 1 and a spiral component 2. The support component 1 provides a structural foundation and stable support for the entire device to ensure its stability in the working state. The spiral component 2 is responsible for driving and connecting the head clamp ear clips at both ends of the structure to achieve fast and smooth adjustment of their spacing. The support component 1 and the spiral component 2 have a clear division of labor in function. The support component 1 serves as a skeleton, bearing the main loads such as the weight of the patient's head and the fixing force and transmitting them to the dental bracket column. It is the static foundation of the entire device. The spiral component 2 is the core of movement, focusing on converting rotational or linear inputs such as manually pulling the ear clips into precise synchronous movements of the ear clips efficiently and with low resistance to achieve dynamic adjustment. Fast adjustment: low damping allows medical staff or patients to easily and quickly adjust the ear clip spacing, improving work efficiency and patient comfort. Smooth operation: reduces the sense of jamming and improves the operating experience. Precise control: low resistance helps achieve finer and more linear position control.

[0045] The support assembly 1 consists of a housing 11, a jaw support mounting assembly 12, and a scale structure 13. The housing 11 and scale structure 13 are manufactured using an integrated molding process, ensuring structural strength and dimensional accuracy. This integrated molding of the housing 11 and scale structure 13 is a key manufacturing process choice. It eliminates assembly errors and ensures the precise position of the scale 13 relative to the reference plane of the housing 11. The integrated structure enhances overall rigidity and deformation resistance. The housing 11 serves as an external casing, encapsulating and protecting the precision components within. The scale structure 13 is located at the upper end of the housing 11 and contains a precision scale embedded within it. This internal scale provides a reference of known dimensions during CBCT scanning. Its precise graduations allow direct measurement of geometric parameters such as distances and angles between key landmarks on the patient's head and face, such as the orbitoauricular plane, nasion, and premental point, on the scanned image. This is used for orthodontic diagnosis and treatment planning, including analysis of dentofacial deformities, appliance design, and treatment evaluation. Its placement at the upper end ensures clear visibility within the scanning field of view without interfering with its primary fixation function. The jaw support mounting assembly 12 is installed in the upper half of the interior of the outer shell 11 and is used to securely fix the entire device on the dental bracket column of the oral CBCT equipment. The assembly includes four parts: a mounting rod fixing plate 121, a mounting back plate 122, a fixing knob 123, and a mounting rod 124. There are two mounting rod fixing plates 121, which are arranged in parallel. The mounting back plate 122 is vertically fixed to the side of the mounting rod fixing plate 121 to enhance the structural rigidity. Circular mounting holes are opened at corresponding positions of the mounting rod fixing plate 121 and the mounting back plate 122, and the mounting rod 124 is passed through these holes. One end of the mounting rod 124 is designed to be inserted into and locked on the standard interface of the CBCT dental bracket column. A securing knob 123 is mounted on the other end or side of mounting rod 124. Tightening this knob securely clamps mounting rod 124 between mounting rod fixing plate 121 and mounting back plate 122, preventing it from loosening or shifting. The two mounting rod fixing plates 121 and mounting back plate 122 together form a stable support frame for mounting rod 124. Securing knob 123, typically a jackscrew or clamping bolt, provides a removable, strong lock, allowing for quick installation and removal of the entire device while ensuring absolute stability during scanning, even under various external forces such as slight movement of the patient's head and vibration of the device, preventing blurred images.

[0046] When in use, the overall structure is installed on the dental bracket post, and the jaw support mounting assembly 12 is used to install the overall structure on the dental bracket post. A mounting hole is reserved on the dental bracket post corresponding to the position of the jaw support mounting assembly 12. The overall structure is installed and fixed under the action of the jaw support mounting assembly 12 and the mounting hole, so that the jaw is supported by the overall structure. The function of the scale structure 13 is to measure some landmark distances and angles of the human head and face, so as to assist orthodontics.

[0047] See also Figure 4The spiral assembly 2 is the core module of this device, enabling the ear clip adjustment function. It consists of two parts: a transmission assembly structure 21 and an ear clip power assembly 22. The transmission assembly 21 serves as the basic framework, providing a mounting base, motion guidance, and necessary support for the ear clip power assembly 22. The ear clip power assembly 22 is the core drive mechanism, with its moving parts directly connected to and driving the ear clips on both sides of the head clamp, achieving synchronized opposite or same-direction movement between them.

[0048] Ear clips are installed at both ends of the spiral component 2. When the patient's head is placed on the chin rest, the positioning part of the ear clip is usually a flexible earplug or ear hook that extends into or fits the patient's external auditory canal, thereby fixing the position of the ear hole area on both sides of the head. This binaural fixation combined with jaw support ensures that the head remains strictly stable during the scanning process, effectively prevents motion artifacts, and obtains clear images. Crucially, the spiral component 2 has the ability to move laterally. By operating such as pulling the ear clips outward with both hands, the distance between the two ear clips can be adjusted synchronously. This adjustment mechanism can adapt to individual differences in head size and width of different patients, and can accurately control the tightness of the ear clips on the ears according to comfort and fixation requirements.

[0049] See also Figure 4 、 5 , a structural part of the transmission component structure 21 of the screw component 2 in the thread adjustment structure of a low-damping fast screw, the transmission component structure 21 is fixedly installed inside the shell member 11 of the support component 1, and its fixing method is various, and can adopt buckles, screws or other reliable connection methods such as Figure 5 The screw holes that may be displayed, the transmission component structure 21 specifically includes a moving part positioning component 211, a sliding guide groove 212, a fixed plate mounting hole 213 and an ear clip fixed rod mounting position 214. The moving part positioning component 211 is usually manufactured by metal casting such as aluminum alloy die casting or precision injection molding process to obtain the required strength and precision. Its main body is a rectangular parallelepiped structure, which provides a mounting platform for the components above. The upper end surface is prefabricated with a fixed plate mounting hole 213 for connecting and fixing the mounting rod fixed plate 121. The bottom surface of the moving part positioning component 211 is processed or formed The ear clip power assembly 22 has two parallel long sliding guide grooves 212 as precise motion guide references. On its two side end faces, ear clip fixing rod mounting positions 214 are provided, which have through holes or mounting interfaces. The sliding guide grooves 212 and the ear clip fixing rod mounting positions 214 work together to install, constrain and guide the moving parts of the ear clip power assembly 22. The core function of the transmission assembly structure 21 is to provide precise linear motion guidance (through the sliding guide grooves 212) and position reference (through its own rigidity and fixed installation) for the moving part of the ear clip power assembly 22.

[0050] The ear clip power assembly 22 includes a fixed part and a movable part, the fixed part includes a bottom fixing plate 221 of the movable part, the bottom fixing plate 221 of the movable part is installed at the bottom of the overall structure, the bottom fixing plate 221 of the movable part is installed at the bottom of the transmission assembly structure 21 in a fixed installation manner, and the movable part is installed on the bottom fixing plate 221 of the movable part and is located inside the transmission assembly structure 21.

[0051] The function of the fixing plate 221 at the bottom of the moving part: the core of the fixing part, which is the static foundation of the entire ear clip power component 22, is firmly fixed to the bottom of the positioning component 211 of the moving part of the transmission component structure 21 by screws or the like.

[0052] The mounting base of the moving part provides rotational support and axial positioning reference for the moving part (primarily the transmission structure 222 and the moving part connecting assembly housing 223). The rotating components of the moving part, such as the rotating bearing 2223, need to define their position relative to the fixed plate 221.

[0053] The moving part is located inside the transmission assembly structure 21, and its movement is constrained by the guide rail groove 212, and the internal space of the structure is used for compact layout. The core function of the ear clip power assembly 22 is to achieve the transmission of guidance, support and driving force. Its moving part is precisely constrained inside the transmission assembly structure 21. The output shaft ear clip fixing rods 226 at both ends of the moving part precisely pass through the ear clip fixing rod mounting positions 214 set at both ends of the transmission assembly structure 21 and extend out, thereby providing a mounting interface for the ear clip. The bottom fixing plate 221 of the fixed part and moving part of the ear clip power assembly 22 is fastened to the bottom surface of the moving part positioning assembly 211 by screws to ensure that the entire ear clip power assembly 22 is absolutely fixed relative to the supporting structure. The sliding guide groove 212 on the transmission assembly structure 21 is precisely matched with the moving guide block 229 on the moving part to form a low-friction linear motion pair, which provides precise guidance for the movement of the ear clip and ensures the linearity and smoothness of its motion trajectory.

[0054] See also Figure 4 、 Figure 6-16 , a moving part of the screw component 2 in a low-damping fast screw thread adjustment structure.

[0055] The core of the moving part is the transmission structure 222, which undertakes the core conversion function of converting the operating force into precise linear motion. The structure mainly includes two sets of screw assemblies 2221, a screw connection structure 2222, a rotating bearing 2223 and a first thread structure 2224. The two sets of screw assemblies 2221 are arranged in parallel, and their inner ends are rigidly connected by the screw connection structure 2222 to ensure that the two screws rotate synchronously. The screw connection structure 2222 is integrated with a rotating bearing 2223. The outer ring of the rotating bearing 2223 is aligned with the inner wall of the transmission assembly structure 21. It is fixed by interference fit, and the inner wall of the transmission assembly structure 21 is specially machined with a precise annular mounting groove to accommodate and position the bearing. This design supports the rotational movement of the transmission structure 222 on a fixed frame. The outer end face of each set of screw assemblies 2221 is provided with an ear clip mounting portion 2225, which is designed to directly or indirectly connect to the ear clip fixing rod 226. The connection between the screw assembly 2221 and the ear clip fixing rod 226 can be a high-strength one-piece molding, or a detachable threaded connection, a snap connection or a plug-in connection.

[0056] The twin-screw synchronous drive uses two sets of parallel screw assemblies 2221 and is rigidly connected by a screw connection structure 2222, thereby ensuring the absolute synchronous movement of the ear clips on both sides.

[0057] The core function of rotating bearing 2223 is to support rotation: it provides a rotational support point for the entire transmission structure 222 (twin screws + connecting structure). The interference fit between the outer ring and the mounting groove on the inner wall of the transmission assembly structure 21 ensures the absolute fixation of the bearing outer ring, preventing it from micro-movement or rotation during operation. Axial positioning: The bearing and the mounting groove jointly limit the axial position (along the screw axis) of the transmission structure 222, so that it can only rotate about its own axis.

[0058] The ear clip mounting portion 2225 and the ear clip fixing rod 226 are the final output ends of the transmission structure 222, converting the screw's rotational motion into linear motion of the ear clip fixing rod 226. Connection options: One-piece molding offers the highest strength and is suitable for miniaturization or high rigidity requirements; removable methods (such as threads) facilitate maintenance or component replacement.

[0059] See also Figure 9 The outer surface of the screw assembly 2221 is machined with a first thread structure 2224. The cross section of the thread teeth of the thread (the cross section perpendicular to the screw axis) has an arc-shaped profile. The arc-shaped tooth design achieves low-friction transmission.

[0060] The significance of arcuate tooth profile: Unlike common triangular or trapezoidal threads, arcuate threads. Transition from point / line contact to line / surface contact: Traditional thread pairs are point or line contacts with high contact stress and large friction resistance. The arcuate thread tooth profile is designed to form a more optimized contact area (line contact or even tiny surface contact), reduce contact pressure, and thus reduce friction. Improve stress distribution: The arcuate profile can better disperse contact stress. Facilitate lubrication: The arcuate groove may be more conducive to the storage of lubricant and the formation of oil film. Reduce sliding resistance: The optimized contact geometry helps to reduce the sliding friction coefficient.

[0061] The moving part also includes a moving part connecting component shell 223, which has a cylindrical structure and is mounted on the outside of the screw assembly 2221 of the transmission structure 222. The screw assembly 2221 can rotate freely in the internal cavity of the moving part connecting component shell 223. A moving guide block clearance hole 225 is provided at the end of the moving part connecting component shell 223 near the end of the ear clip mounting part 2225. The shape and position of the clearance hole 225 are designed to accommodate and allow the moving guide block 229 on the moving part to pass through. When the guide sliding assembly 227 is installed inside the moving part connecting component shell 223, the moving guide block 229 at the bottom of the guide sliding assembly 227 is just embedded in and passes through this clearance hole 225, so that the moving guide block 229 can extend downward and engage with the sliding guide groove 212 on the bottom surface of the transmission assembly structure 21.

[0062] Functions of the mobile portion connecting component housing 223: Connection hub: connects the guide sliding assembly 227 (with the second thread 230 inside) and the movable guide block 229 into an integral unit (ie, the movable housing portion of the movable part).

[0063] The rotational-translational conversion interface fits over the rotating screw assembly 2221, but is constrained to linear motion, not rotation, by an internal threaded pair (which mates with the guide slide assembly 227) and an external guide block 229. Therefore, when the screw assembly 2221 rotates, it forces the movable connecting assembly housing 223 to translate along the screw axis, along with the connected guide slide assembly 227 and ear clip fixing rod 226. This converts the screw's rotational motion into linear motion of the housing (and thus the ear clip).

[0064] Movable guide block clearance hole 225: This hole is formed in cylindrical housing 223 to allow a movable guide block 229, mounted on the guide slide assembly 227 below, to penetrate the housing and contact the fixed guide rail 212 at the bottom. The linear motion of housing 223 is constrained by movable guide block 229 on guide rail 212. This hole must have sufficient clearance to avoid interference with movable guide block 229.

[0065] The movable portion achieves movement of the ear clip by the relative motion between the transmission structure 222 and the movable portion connecting assembly housing 223. When the ear clip (mounted on the ear clip fixing rod 226) is operated (for example, by grasping both ear clips with both hands and pulling them outward simultaneously), the pulling or pushing force applied to the ear clip fixing rod 226 is transmitted to the movable portion connecting assembly housing 223. Because the movable portion connecting assembly housing 223 forms a threaded engagement with the first threaded structure 2224 of the screw assembly 2221 through its internal guide sliding assembly 227, and the movable guide block 229 at its bottom is constrained within the fixed sliding guide groove 212 and can only move linearly, the applied linear force forces the movable portion connecting assembly housing 223 to move axially relative to the rotating transmission structure 222. This relative motion is converted into rotation of the transmission structure 222 via the threaded pair. Of particular note, the two sets of screw assemblies 2221 are rigidly connected by the screw connecting structure 2222, and the first threaded structures 2224 on the two sets of screws are designed to have opposite rotational directions. Therefore, when the transmission structure 222 rotates, it drives the left and right movable connecting assembly housings 223 and their connected ear clip fixing rods 226 to move synchronously in opposite directions, with one moving away from the opening and the other also moving away from the opening, thereby increasing or decreasing the distance between the ear clips. The operator pulling the ear clips directly activates the screw mechanism, achieving adjustment of the ear clip spacing.

[0066] Motion input: The clear operation method is to hold the ear clip with both hands and pull directly (linear input). This is different from traditional knob rotation input, is more ergonomic and intuitive, and may be faster.

[0067] Motion conversion: The pulling force acts on the housing 223 of the moving part connecting component. The housing 223 is restricted by the guide rail and can only move in a straight line. The second thread 230 of the guide sliding component 227 inside the housing 223 is engaged with the first thread structure 2224 of the screw assembly 2221. The linear motion forces the thread pair to produce relative motion. Since the rotational freedom of the screw 2221 is not completely restricted (supported by bearings but not driven), under the action of friction and meshing force, the screw assembly 2221 rotates (that is, the transmission structure 222 rotates).

[0068] Synchronous reversal of twin screws: Since the two sets of screws 2221 are rigidly connected and have opposite thread rotation directions, when one screw is driven to rotate, the other must be synchronously reversed.

[0069] The rotation of screw assembly 2221, through the second thread 230 inside the housing 223 of the corresponding movable portion, in turn drives the housing 223 along the screw axis. Because the threads on both sides rotate in opposite directions, when the central transmission structure 222 rotates, the housings 223 on both sides inevitably move in opposite directions, one to the left and the other to the right, moving away from or toward the center simultaneously, thereby achieving synchronized opening and closing of the ear clip spacing.

[0070] See also Figure 17-19 , a structural part of the guide sliding component 227 of the moving part in a low-damping fast spiral thread adjustment structure.

[0071] The guide sliding assembly 227 is a key precision component for realizing spiral transmission and linear guidance in the moving part. One end of the guide sliding assembly 227 is engaged with the first thread structure 2224 on the screw assembly 2221 through a thread. A moving guide block 229 is fixedly installed at the bottom thereof, for example, by screws or integral molding. The core function of the moving guide block 229 is precise guidance. Its main body is a columnar structure, but two opposite side surfaces are processed into planes. This plane design is to match the geometric shape of the sliding guide groove 212 on the bottom surface of the moving part positioning assembly 211, which is usually a rectangular or dovetail groove, to ensure that the moving guide block 229 can slide The guide rail groove 212 slides back and forth smoothly, limiting the other degrees of freedom except along the groove direction. The main body of the guide sliding component 227 is installed inside the moving part connecting component shell 223. A limit mounting hole 224 is opened at one end of the moving part connecting component shell 223 close to the ear clip mounting portion 2225. A raised limit structure 228 is provided on the outer wall of the guide sliding component 227. The limit structure 228 can be integrally formed with the guide sliding component 227 body, or it can be fixed to its outer wall as an independent part by welding, bonding or screws. The guide sliding component 227 and the moving part connecting component are connected. The assembly of the component housing 223 is achieved by the cooperation of the limiting mounting hole 224 and the limiting structure 228: the limiting structure 228 is embedded in the limiting mounting hole 224 to prevent the guide sliding component 227 from axially moving or rotating relative to the housing 223, so that the two are firmly combined into an integral motion unit. The most critical feature of the guide sliding component 227 is that a second thread structure 230 is processed on its inner wall. The rotation direction of the second thread structure 230 is opposite to the rotation direction of the first thread structure 2224 on the screw component 2221. It is this pair of thread structures with opposite rotation directions that engage with each other to form a combination of rotational motion and linear motion. The spiral transmission pair that can convert movement into each other adopts a special contact design to achieve low friction: the cross-sectional shape of the thread teeth of the raised part of the second thread structure 230 is matched with the cross-sectional shape of the thread groove of the first thread structure 2224, so that when the two are engaged, they only contact at a single point on any cross-section. When considering the length of the entire thread tooth, this contact is a ridge line, i.e., the contact line, of the raised part of the second thread structure 230 and the concave surface, i.e., the groove surface, of the first thread structure 2224. The second thread structure 230 slides on the first thread structure 2224 along this contact line.

[0072] The second bearing thread structure 230 is a component that engages with the first thread 224 of the screw; Install the moving guide block 229: transfer the linear motion constraint to the bottom guide rail; Connect the moving part to the component housing 223: fix itself to the housing 223 through the limiting structure 228 and the limiting mounting hole 224, so that the movement of the housing 223 is consistent with it.

[0073] The limiting structure 228 and the limiting mounting holes 224 provide a simple and reliable axial and circumferential positioning method, ensuring that there is no relative movement between the guide slide assembly 227 and the movable portion connecting assembly housing 223, forming a rigid moving unit. One-piece molding provides superior strength, while separate manufacturing facilitates assembly and material selection.

[0074] Point Contact: Viewed from any cross section perpendicular to the screw axis, the crest (convex surface) of the second thread 230 contacts the groove (concave surface) of the first thread 224 at only one point. This is ensured by the specific arcuate cross-sectional profiles of the two.

[0075] Line contact: When observing the entire thread along the axis of the screw, this point contact expands into a spatial curve (contact line) along the length of the thread. The top edge line of the second thread 230 and the tooth groove surface of the first thread 224 form a continuous spatial line contact.

[0076] Reduce contact area: Compared with surface contact, line contact greatly reduces the actual contact area. According to the basic friction law, friction force = friction coefficient * normal pressure. Under the same normal load, the smaller the contact area, the greater the contact pressure. However, the total friction force mainly depends on the sum of the friction coefficient and the normal load, rather than the contact area. For sliding friction, especially boundary lubrication or mixed lubrication, the contact area is reduced. Therefore, this line contact design can significantly reduce the sliding friction resistance, thereby achieving low damping. Its effect is similar to that of a ball screw (point contact) being better than a sliding screw (surface contact).

[0077] The limiting structure 228 and the guide sliding assembly 227 can also be installed and connected in the following installation method: a waist-shaped mounting groove is provided on the outer wall of the guide sliding assembly 227, and a spring is provided inside the mounting groove, one end of the spring is fixedly installed on the inner wall of the waist-shaped mounting groove, and the other end is fixedly installed on the outer wall of the limiting structure 228, and a card slot is installed on the inner wall of the waist-shaped mounting hole, and a buckle is installed on the limiting structure 228. Through the action of the card slot and the buckle, the limiting structure 228 is movably connected on the inner wall of the waist-shaped mounting hole. When the guide sliding assembly 227 is installed on the moving part connecting assembly housing 223, press the limiting structure 228, and then insert the guide sliding assembly 227 into the interior of the moving part connecting assembly housing 223, and the limiting structure 228 is just installed in the limiting mounting hole 224, and the limiting structure 228 is pushed out by the action of the spring. At this time, the limiting structure 228 is just stuck in the interior of the limiting mounting hole 224, thereby playing a fixing role.

[0078] The purpose of the detachable design is to provide a quick disassembly and assembly solution without tools. This is very convenient for cleaning, maintenance (such as cleaning the guide groove, lubricating the thread pair), or replacing the guide slide assembly 227 and moving the guide block 229.

[0079] Press to unlock steps: 1. Finger pressing limit structure 228; 2. Compress the spring and at the same time the buckle is released from the slot on the inner wall of the waist-shaped groove; 3. The limiting structure 228 retracts into the waist-shaped groove; 4. Insertion: Insert the guide sliding assembly 227 into the housing 223.

[0080] Spring pop-up locking steps: 1. When the limiting structure 228 is aligned with the limiting mounting hole 224 on the housing 223, release your finger; 2. The spring ejects the limiting structure 228; 3. The limiting structure 228 is embedded in the limiting mounting hole 224 (to achieve axial and circumferential limiting), and at the same time, its buckle may rebound and be stuck into the slot on the inner wall of the waist-shaped groove (providing additional holding force to prevent it from shaking in the hole 224).

[0081] Waist-shaped groove: provides space and guidance for the telescopic movement of the limiting structure 228.

[0082] Spring: Provides ejection and retention force.

[0083] Slot / clip: provides a clear positioning point and auxiliary retention force on the telescopic path to prevent the limiting structure 228 from accidentally loosening.

[0084] The above describes in detail the preferred embodiments of this patent, but this patent is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in this field without departing from the purpose of this patent.

Claims

1. A low-damping fast spiral thread adjustment structure, characterized in that: include: Support assembly, used to support the overall structure and connect the dental bracket of the oral CBCT equipment; A screw assembly, fixedly connected to the support assembly, for driving the head fixture to achieve synchronous reverse movement; The spiral assembly includes: The transmission component structure is fixed inside the support component; The ear clip power assembly includes a fixed part and a movable part, wherein the movable part is guided by the transmission assembly structure to realize linear motion.

2. The thread adjustment structure of the low-damping fast screw according to claim 1, characterized in that: The support assembly comprises: The outer shell covers the entire internal structure; The jaw support mounting assembly is fixed to the upper part of the housing and is used to connect the dental bracket post; The scale structure is integrally formed with the outer shell and arranged at the upper end thereof, and a scale is embedded inside.

3. The thread adjustment structure of the low-damping fast screw according to claim 2, characterized in that: The jaw support mounting assembly comprises: Two mounting rod fixing plates, mounting back plate, fixing knobs and mounting rods; The mounting rod passes through the circular mounting holes of the mounting rod fixing plate and the mounting back plate, one end of the mounting rod is connected to the fixing knob, and the other end is adapted to the mounting hole of the dental bracket column.

4. The thread adjustment structure of the low-damping fast screw according to claim 1, characterized in that: The transmission assembly structure includes: The bottom surface of the moving part positioning assembly is provided with two sets of sliding guide grooves; The ear clip fixing rod installation position is located on the sides of both ends of the positioning assembly of the moving part; The fixing plate mounting hole is provided on the upper end surface of the positioning assembly of the moving part.

5. The thread adjustment structure of the low-damping fast screw according to claim 1, characterized in that: The moving part of the ear clip power assembly includes: A transmission structure comprising two sets of screw assemblies and a screw connection structure connecting the two sets; An ear clip mounting portion is provided at the end of the screw assembly, and a first thread structure is provided on the outer wall.

6. The thread adjustment structure of the low-damping fast screw according to claim 5, characterized in that: The cross section of the first thread structure is arc-shaped, and the threads of the two sets of screw assemblies have opposite rotation directions.

7. The thread adjustment structure of the low-damping fast screw according to claim 1, characterized in that: The mobile unit further includes: The moving part connecting assembly housing is sleeved on the outside of the screw assembly; The guide sliding component is arranged inside the housing of the moving part connecting component, and the inner wall of the guide sliding component is provided with a second thread structure with a rotation direction opposite to that of the first thread structure.

8. The thread adjustment structure of the low-damping fast screw according to claim 7, characterized in that: The second thread structure and the first thread structure form a line contact pair: It presents single-point contact on any cross section, forming continuous line contact between convex ridges and concave surfaces in three-dimensional space.

9. The thread adjustment structure of the low-damping fast screw according to claim 7, characterized in that: A movable guide block is fixed at the bottom of the guide sliding assembly; The movable guide block is a columnar structure with two flat sides, adapted to the sliding guide groove to achieve linear guidance.

10. The thread adjustment structure of the low-damping fast screw according to claim 7, characterized in that: The guide sliding assembly and the moving part connecting assembly housing are fixed by the limiting structure and the limiting mounting hole; The limiting structure can be elastically and telescopically installed in the waist-shaped installation groove of the guide sliding component and locked by a spring and a buckle mechanism.

11. The thread adjustment structure of the low-damping fast screw according to claim 2, characterized in that: The scale structure is used to measure the distance and angle of the head and face landmarks.

12. The thread adjustment structure of the low-damping fast screw according to claim 1, characterized in that: The ear clip spacing of the spiral assembly is adjusted by pulling the ear clips synchronously with both hands, driving the movable part to connect the assembly housing and the transmission structure to move relative to each other, and the reverse thread pair converts the linear input into the synchronous rotation of the twin screws.

13. The thread adjustment structure of the low-damping fast screw according to claim 1, characterized in that: The fixed part of the ear clip power assembly includes a fixing plate at the bottom of the moving part, which is fixed to the bottom of the transmission assembly structure by screws.

14. The thread adjustment structure of the low-damping fast screw according to claim 5, characterized in that: The screw connection structure of the transmission structure is provided with a rotating bearing, the outer wall of which is interference-fitted with the inner wall of the transmission assembly structure.

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