Threaded adjustment structure for low-damping quick screw

Abstract

The utility model discloses a low damping quick spiral's thread adjusting structure, include: support subassembly is used for supporting integral structure and the dental tray column of connecting oral cavity CBCT equipment, spiral subassembly is fixedly connected with support subassembly, is used for driving head clamp to realize synchronous reverse movement, spiral subassembly includes: transmission subassembly structure, is fixed in support subassembly inside, ear clip power component contains fixed part and moving part, the moving part is guided to realize linear motion by transmission subassembly structure. Through the three fixed systems of rigid locking of jaw support mounting component and dental tray column, double ear clip synchronous reverse clamping and the formation of shell piece integrated jaw support surface, realize head six degrees of freedom full constraint, reduce the influence of motion artifact to cephalometric analysis.

Description

Technical Field

[0001] This utility model relates to an adjustment structure, specifically a low-damping, fast-speed spiral thread adjustment structure. Background Technology

[0002] In the field of orthodontics, cone-beam computed tomography (CBCT) has become a core tool for three-dimensional imaging of the head and face. To achieve accurate orthodontic diagnosis and treatment planning, it is necessary to fix the patient's head position during the scan and acquire quantifiable anatomical landmark data (such as the orbitoauricular plane angle, the distance between the nasal root and the anterior chin point, etc.). Current technologies typically employ a combination of dental posts and head fixation clamps, but this approach has significant drawbacks in practical applications.

[0003] Limitations of existing head fixation devices

[0004] (1) Insufficient positioning stability

[0005] Traditional clamps often employ a single-point chin rest combined with an elastic ear clip structure. During scanning, even slight patient movements can cause head displacement, resulting in motion artifacts. In particular, when the ear clip's clamping force is insufficient, it is difficult to maintain the three-dimensional coordinate stability of the ear canal area, affecting the accuracy of subsequent cephalometric analysis.

[0006] (2) Lack of integrated measurement benchmarks

[0007] Existing devices typically lack integrated dimensional calibration structures, requiring physicians to manually add scales after scanning or rely on software simulation for calibration, leading to systematic errors in measurement results. Some solutions that attempt to attach scales to the outside of the clamp are prone to projection distortion due to installation misalignment or scanning angle.

[0008] (3) Defects in adjustment efficiency and comfort

[0009] Ear clip spacing adjustment mechanisms often use gear and rack or ordinary lead screw drives, which have some problems:

[0010] High operating damping: Traditional threaded surfaces have high frictional resistance, requiring medical staff to turn the knob forcefully for adjustment, which is inefficient and can easily cause discomfort to patients;

[0011] Asynchronous adjustment: Unilateral adjustment leads to asymmetrical force on the head, which may force the patient's head to tilt and disrupt the natural head position. Utility Model Content

[0012] The purpose of this invention is to provide a low-damping, fast-speed spiral thread adjustment structure to solve the problems mentioned in the background art.

[0013] To achieve the above objectives, this utility model provides the following technical solution:

[0014] A low-damping, high-speed spiral thread adjustment structure, comprising:

[0015] A support assembly is used to support the overall structure and connect the dental CBCT device; a 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; and an ear clamp power assembly, which includes a fixed part and a moving part, wherein the moving part is guided by the transmission assembly structure to achieve linear movement.

[0016] As a further embodiment of this utility model: the support component includes: an outer shell that covers the overall internal structure; a chin support mounting component that is fixed to the upper part inside the outer shell and is used to connect the dental tray post; and a scale structure that is integrally formed with the outer shell and located at its upper end, with a scale embedded inside.

[0017] As a further embodiment of this utility model: the chin 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 plates and the mounting back plate, with one end connected to the fixing knob and the other end adapted to the mounting hole of the dental tray post.

[0018] As a further embodiment of this utility model: the transmission component structure includes: a moving part positioning component, with two sets of sliding guide rail grooves on the bottom surface; an ear clip fixing rod mounting position, located on both sides of the moving part positioning component; and a fixing plate mounting hole, located on the upper end surface of the moving part positioning component.

[0019] As a further embodiment of this utility model: 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; the end of the screw assembly is provided with an ear clip mounting part, and the outer wall is provided with a first thread structure.

[0020] As a further embodiment of this utility model: the cross-section of the first thread structure is arc-shaped, and the threads of the two sets of screw assemblies have opposite directions.

[0021] As a further embodiment of this utility model, the moving part further includes: a moving part connecting component housing, sleeved on the outside of the screw assembly; and a guide sliding component, disposed inside the moving part connecting component housing, the inner wall of which is provided with a second thread structure with a rotation direction opposite to that of the first thread structure.

[0022] As a further embodiment of this utility model: the second thread structure and the first thread structure constitute a line contact pair: they are in single-point contact on any cross-section, and form a continuous line contact between the raised ridge and the concave surface in three-dimensional space.

[0023] As a further embodiment of this utility model: a movable guide block is fixed at the bottom of the guide sliding assembly;

[0024] The movable guide block has a columnar structure with flat sides, and is adapted to a sliding guide groove to achieve linear guidance.

[0025] As a further embodiment of this utility model: the outer shell of the guide sliding assembly and the moving part connecting assembly is fixed by 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 assembly and locked by a spring and a buckle mechanism.

[0026] As a further aspect of this utility model: the scale of the scale structure is used to measure the distance and angle of the head and face landmarks.

[0027] As a further embodiment of this utility model: the ear clip spacing of the spiral assembly is adjusted by pulling the ear clips simultaneously with both hands, driving the moving part to move relative to the outer shell of the connecting assembly and the transmission structure, and the reverse thread pair converts the linear input into the synchronous rotation of the twin screws.

[0028] As a further embodiment of this utility model: the fixing 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.

[0029] As a further embodiment of this utility model: 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 component structure.

[0030] Compared with the prior art, the beneficial effects of this utility model are:

[0031] By using a three-point fixation system formed by the rigid locking of the chin support mounting components and the dental support posts, the synchronous reverse clamping of the ear clips, and the integrated chin support surface of the outer shell, the head is fully constrained in six degrees of freedom, reducing the impact of motion artifacts on cephalometric analysis.

[0032] The line contact pair consisting of an arc-shaped first thread and a reverse second thread reduces frictional resistance. Combined with the interference support of the rotating bearing, the planar moving guide block, and the guide rail groove (low friction pair), medical staff can complete the full stroke adjustment with one hand, improving efficiency.

[0033] Based on the synchronous reverse transmission mechanism of the twin-screw assembly with opposite rotation and rigid connection structure, the symmetry error of the ear clip spacing adjustment is small. There is no torsional torque input to the patient's head during the adjustment process, resulting in a high rate of natural head position retention and avoiding compensatory displacement of the temporomandibular joint caused by traditional unilateral adjustment. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of a threaded adjustment structure for a low-damping, fast-speed spiral.

[0035] Figure 2 This is another schematic diagram of a threaded adjustment structure for a low-damping, fast-speed spiral.

[0036] Figure 3 A schematic diagram of the threaded adjustment structure of the low-damping fast spiral after removing the outer shell.

[0037] Figure 4 This is an exploded view of the threaded adjustment structure of a low-damping, high-speed spiral.

[0038] Figure 5 This is a schematic diagram of the transmission component structure in a low-damping, high-speed spiral threaded adjustment structure.

[0039] Figure 6 This is a schematic diagram of the spiral assembly in a low-damping, high-speed spiral thread adjustment structure.

[0040] Figure 7 This is an exploded view of the spiral assembly.

[0041] Figure 8 This is the left view of the spiral component.

[0042] Figure 9 This is a schematic cross-sectional view along direction AA of the left view of the spiral assembly.

[0043] Figure 10 This is an exploded view of the vertical direction of a low-damping, fast-speed spiral threaded adjustment structure.

[0044] Figure 11 This is a front view of the exploded vertical view of a low-damping, fast-speed spiral threaded adjustment structure.

[0045] Figure 12 The left view of the exploded vertical view of the threaded adjustment structure of the low-damping fast-speed spiral.

[0046] Figure 13 The exploded view of the vertical direction of the threaded adjustment structure of the low-damping fast spiral is shown in the left view and the sectional view along the BB direction.

[0047] Figure 14 This is a schematic diagram of the transmission structure in the ear clip power assembly.

[0048] Figure 15 This is a left view of the transmission structure in the ear clip power assembly.

[0049] Figure 16 This is a cross-sectional view along the CC direction of the transmission structure in the ear clip power assembly.

[0050] Figure 17 This is a schematic diagram of the guide sliding assembly.

[0051] Figure 18 The left view of the guide sliding component.

[0052] Figure 19 A cross-sectional view along the left (DD) direction of the guide sliding component. Detailed Implementation

[0053] The technical solution of this patent will be further described in detail below with reference to specific embodiments.

[0054] Please see Figure 1-3 A low-damping, fast-acting spiral adjustment structure is mainly composed of a support component 1 and a spiral component 2. The support component 1 provides the structural foundation and stable support for the entire device, ensuring its stability in operation. The spiral component 2 is responsible for driving and connecting the head clamp ear clips located at both ends of the structure, enabling rapid and smooth adjustment of their spacing. The support component 1 and the spiral component 2 have a clear functional division. The support component 1, as the skeleton, bears the main loads such as the weight of the patient's head and the fixing force and transmits them to the dental tray post, serving as the static foundation of the entire device. The spiral component 2 is the motion core, focusing on efficiently and with low resistance converting rotational or linear inputs, such as manually pulling the ear clips, into precise synchronous movement of the ear clips, achieving dynamic adjustment. Rapid 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 feeling of jamming and enhances the operating experience. Precise control: Low resistance helps to achieve more precise and linear position control.

[0055] The support assembly 1 consists of an outer shell 11, a jaw support mounting assembly 12, and a scale structure 13. The outer shell 11 and scale structure 13 are manufactured using a one-piece molding process, ensuring structural strength and dimensional accuracy. This one-piece molding of the outer shell 11 and scale structure 13 is a key manufacturing process choice. It eliminates assembly errors, ensures the precise positional relationship of the scale 13 relative to the reference plane of the outer shell 11, and the one-piece structure improves overall rigidity and resistance to deformation. The outer shell 11, as the external housing, encapsulates and protects the internal precision components. The scale structure 13 is located at the upper end of the outer shell 11, and contains a precision scale. The internal scale provides a reference point 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, nasal root point, and anterior chin point, on the scanned image. This is used for orthodontic diagnosis, treatment planning such as analyzing dentofacial deformities, designing appliances, and evaluating treatment effectiveness. Its upper position ensures clear visibility within the scanning field of view without affecting the main fixation function. The chin support assembly 12 is installed in the upper part of the outer casing 11 to securely fix the entire device to the dental tray post of the CBCT dental device. This assembly comprises four parts: a mounting rod fixing plate 121, a mounting back plate 122, a fixing knob 123, and a mounting rod 124. Two mounting rod fixing plates 121 are provided, arranged in parallel. The mounting back plate 122 is vertically fixed to the side of the mounting rod fixing plate 121, enhancing structural rigidity. Circular mounting holes are provided at corresponding positions on the mounting rod fixing plate 121 and the mounting back plate 122, through which the mounting rod 124 passes. One end of the mounting rod 124 is designed to be inserted into and locked onto the standard interface of the CBCT dental tray post. The other end or side of the mounting rod 124 is equipped with a fixing knob 123. By tightening this knob, the mounting rod 124 can be securely clamped between the mounting rod fixing plate 121 and the mounting back plate 122, preventing it from loosening or shifting. The two mounting rod fixing plates 121 and the mounting back plate 122 together form a stable support frame for the mounting rod 124. The fixing knob 123 typically provides a removable, strong lock for a set screw or clamping bolt, allowing for quick installation and removal of the entire device, while ensuring absolute stability during scanning under various external forces such as slight movement of the patient's head or equipment vibration, thus avoiding image blurring.

[0056] When in use, the overall structure is installed on the dental tray post. The jaw support mounting component 12 is used to install the overall structure on the dental tray post. The dental tray post has mounting holes corresponding to the positions of the jaw support mounting component 12. The jaw support mounting component 12 and the mounting holes are used to install and fix the overall structure, thereby supporting the jaw. The scale structure 13 is used to measure some landmark distances and angles of the human head and face, thereby assisting in orthodontics.

[0057] Please see Figure 4The spiral assembly 2 is the core module of this device that enables 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 structure 21 serves as the basic frame, providing a mounting base, motion guide, and necessary support for the ear clip power assembly 22. The ear clip power assembly 22 is the core drive mechanism, and its moving part is directly connected to and drives the head clip ear clips on both sides, enabling them to move synchronously in opposite directions or in the same direction.

[0058] Ear clips are attached to both ends of the spiral assembly 2. When the patient's head is placed on the chin rest, the positioning part of the ear clips, typically a flexible ear plug or ear hook, inserts into or conforms to the patient's external auditory canal, thereby fixing the position of the ear canals on both sides of the head. This dual-ear fixation, combined with chin support, ensures strict head stability during scanning, effectively preventing motion artifacts and obtaining clear images. Crucially, the spiral assembly 2 has lateral movement capability. By operating, such as pulling the ear clips outward with both hands, the distance between the two ear clips can be adjusted simultaneously. This adjustment mechanism can accommodate individual differences in head size and width among different patients and can precisely control the tightness of the ear clips on the ears according to comfort and fixation requirements.

[0059] Please see Figure 4 , 5 In a low-damping, fast-speed spiral thread adjustment structure, the transmission component structure 21 of the spiral assembly 2 is a structural part. The transmission component structure 21 is fixedly installed inside the outer shell 11 of the support assembly 1. The fixing method is varied, and can include clips, screws, or other reliable connection methods such as... Figure 5 The screw hole positions that may be shown, the transmission component structure 21 specifically includes a moving part positioning component 211, a sliding guide groove 212, a fixing plate mounting hole 213, and an ear clip fixing 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, to obtain the required strength and precision. Its main body is a cuboid structure, providing a mounting platform for the components above. Its upper end face has a pre-drilled fixing plate mounting hole 213 for connecting and fixing the mounting rod fixing plate 121. The bottom surface of the moving part positioning component 211 is machined or formed. The device has two parallel, elongated sliding guide grooves 212, which serve as precise motion guidance references. On both sides of these grooves, there are ear clip fixing rod mounting positions 214, 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.

[0060] 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 by a fixed installation method. The movable part is installed on the bottom fixing plate 221 of the movable part and is located inside the transmission assembly structure 21.

[0061] The function of the bottom fixing plate 221 of the moving part: It is the core of the fixing part and the static foundation of the entire ear clip power assembly 22. It is firmly fixed to the bottom of the moving part positioning assembly 211 of the transmission assembly structure 21 by screws, etc.

[0062] Mounting base for the moving part: Provides rotational support and axial positioning reference for the moving part (mainly the transmission structure 222 and the housing 223 of the moving part connecting assembly). Rotating components of the moving part, such as the rotating bearing 2223, need to have their positions defined relative to the fixed plate 221.

[0063] The moving part is located inside the transmission assembly structure 21, and its movement is constrained by the guide rail groove 212, utilizing the internal space of this structure for a compact layout.

[0064] The core function of the ear clip power assembly 22 is to provide guidance, support, and drive force transmission. Its moving part is precisely constrained within 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 located at both ends of the transmission assembly structure 21 and extend outwards, thus providing an installation interface for the ear clip. The bottom fixing plate 221 of the moving part of the ear clip power assembly 22 is fastened to the bottom surface of the moving part positioning assembly 211 with screws, ensuring that the entire ear clip power assembly 22 is absolutely fixed relative to the support structure. The sliding guide groove 212 on the transmission assembly structure 21 precisely engages with the moving guide block 229 on the moving part, forming a low-friction linear motion pair, providing precise guidance for the movement of the ear clip and ensuring the linearity and smoothness of its movement trajectory.

[0065] Please see Figure 4 , Figure 6-16 The moving part of the spiral assembly 2 in a low-damping, fast-speed spiral thread adjustment structure.

[0066] The core of the moving part is the transmission structure 222, which undertakes the core conversion function of transforming operating force into precise linear motion. This structure mainly includes two sets of screw assemblies 2221, a screw connecting structure 2222, a rotary 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 connecting structure 2222 to ensure that the two screws rotate synchronously. The rotary bearing 2223 is integrated on the screw connecting structure 2222. The outer ring of the rotary bearing 2223 is flush with the inner wall of the transmission assembly structure 21. The bearing is fixed by an interference fit. The inner wall of the transmission component 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. Each screw assembly 2221 has an ear clip mounting part 2225 on its outer end face. This mounting part is designed to directly or indirectly connect 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, snap-fit ​​connection, or plug-in connection, etc.

[0067] The dual-screw synchronous drive uses two sets of parallel screw assemblies 2221 and is rigidly connected by a screw connection structure 2222, ensuring the absolute synchronous movement of the ear clips on both sides.

[0068] The core function of the rotating bearing 2223 is to support rotation: the entire transmission structure 222 (twin screw + connecting structure) provides a rotational support point. The interference fit between the outer ring and the mounting groove on the inner wall of the transmission component structure 21 ensures the absolute fixation of the bearing's outer ring, preventing fretting or rotation during operation. Axial positioning: the bearing and the mounting groove together restrict the axial position of the transmission structure 222 (along the screw axis), allowing it to rotate only around its own axis.

[0069] The ear clip mounting part 2225 and the ear clip fixing rod 226 are the final output ends of the transmission structure 222, converting the rotational motion of the screw into the linear motion of the ear clip fixing rod 226. Connection method selection: One-piece molding offers the highest strength and is suitable for miniaturization or high rigidity requirements; detachable methods (threaded, etc.) facilitate maintenance or component replacement.

[0070] Please see Figure 9 A first thread structure 2224 is machined on the outer surface of the screw assembly 2221. The cross-section of the thread teeth (the section perpendicular to the screw axis) has an arc-shaped profile. The arc-shaped tooth design achieves low-friction transmission.

[0071] The significance of curved thread profiles: Unlike common triangular or trapezoidal threads, curved threads offer several advantages. First, they transform point / line contact into line / surface contact: Traditional threaded pairs involve point or line contact, resulting in high contact stress and frictional resistance. Curved thread profiles aim to create a more optimized contact area (line contact or even small surface contact), reducing contact pressure and thus friction. Second, they improve stress distribution: the curved profile better disperses contact stress. Third, they facilitate lubrication: the curved grooves may be more conducive to lubricant storage and oil film formation. Fourth, they reduce sliding resistance: the optimized contact geometry helps reduce the coefficient of sliding friction.

[0072] The moving part also includes a moving part connecting component housing 223, which is cylindrical in shape and is fitted outside 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 housing 223. A moving guide block clearance hole 225 is provided at the end of the moving part connecting component housing 223 near 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 housing 223, the moving guide block 229 at the bottom of the guide sliding assembly 227 is precisely 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 component structure 21.

[0073] Function of the housing 223 for the moving part connecting component:

[0074] Connection hub: Connects the guide sliding assembly 227 (with a second thread 230 inside) and the moving guide block 229 into a single unit (i.e., the movable housing part of the moving part).

[0075] The interface for switching between rotation and translation: It fits onto the rotating screw assembly 2221, but is restricted to linear motion only by an internal threaded pair (which mates with the guide sliding assembly 227) and an external guide block 229, preventing rotation. Therefore, when the screw assembly 2221 rotates, it forces the moving part connecting assembly housing 223 to translate along the screw axis, along with the connected guide sliding assembly 227 and the ear clip fixing rod 226. In other words, the rotational motion of the screw is converted into linear motion of the housing (and the ear clip).

[0076] Moving guide block clearance hole 225: A hole is made in the cylindrical outer shell 223 so that the moving guide block 229, fixed on the lower guide sliding assembly 227, can penetrate downward through the outer shell and contact the bottom fixed guide rail groove 212. The linear movement of the outer shell 223 is constrained to the guide rail groove 212 by the moving guide block 229. This hole must have sufficient clearance to avoid interference with the moving guide block 229.

[0077] The movement of the ear clips is achieved through the relative motion between the transmission structure 222 and the moving part connecting assembly housing 223. When the ear clips (mounted on the ear clip fixing rod 226) are operated (e.g., by holding both ear clips and pulling them outwards simultaneously), the pulling or pushing force applied to the ear clip fixing rod 226 is transmitted to the moving part connecting assembly housing 223. Since the moving part connecting assembly housing 223 forms a threaded engagement with the first threaded structure 2224 on the screw assembly 2221 through its internal guide sliding assembly 227, and its bottom moving guide block 229 is constrained within the fixed sliding guide groove 212 and can only move linearly, the applied linear force forces the moving part connecting assembly housing 223 to move axially relative to the rotating transmission structure 222. This relative motion is converted into the rotation of the transmission structure 222 through the threaded pair. It is particularly noteworthy that the two sets of screw assemblies 2221 are rigidly connected by the screw connecting structure 2222, and the helix directions of the first threaded structures 2224 on the two sets of screws are designed to be opposite. Therefore, when the transmission structure 222 rotates, it drives the moving parts connecting assembly housing 223 on the left and right sides and their connected ear clip fixing rods 226 to move synchronously in opposite directions. One moves away from the opening, and the other also moves away from the opening, thereby increasing or decreasing the ear clip spacing. The direct result of the operator pulling the ear clips is that the screw mechanism is driven, thereby adjusting the ear clip spacing.

[0078] Motion input: The explicit operation method is to hold the ear clips with both hands and pull them directly (linear input). This differs from traditional knob rotation input, is more ergonomic and intuitive, and may be faster.

[0079] Motion conversion: The tension is applied to the housing 223 of the moving part connecting component. The housing 223 is restricted to linear motion by the guide rail. The second thread 230 of the guide sliding component 227 inside the housing 223 meshes with the first thread structure 2224 of the screw assembly 2221. The linear motion forces the threaded pair to generate relative motion. Since the rotational degree of freedom of the screw 2221 is not completely restricted (it is supported by a bearing but has no drive), the screw assembly 2221 rotates under the action of friction and meshing force (i.e., the transmission structure 222 rotates).

[0080] Twin-screw synchronous reverse rotation: Since the two sets of screws 2221 are rigidly connected and the threads rotate in opposite directions, when one screw is driven to rotate, the other will inevitably reverse synchronously.

[0081] The rotation of the screw assembly 2221, through the second thread 230 inside the connecting assembly housing 223 that mates with it, in turn drives the housing 223 on that side to move along the screw axis. Because the threads on both sides turn in opposite directions, when the transmission structure 222 in the middle rotates, the housings 223 on both sides will inevitably move in opposite directions, one to the left and the other to the right, moving away from or towards the center simultaneously, thereby achieving the synchronous opening and closing of the ear clip spacing.

[0082] Please see Figure 17-19 The guide sliding assembly 227 of the moving part in a low-damping fast spiral threaded adjustment structure.

[0083] The guide sliding assembly 227 is a key precision component in the moving part that realizes helical transmission and linear guidance. One end of it engages with the first thread structure 2224 on the screw assembly 2221 via a thread, and a moving guide block 229 is fixedly mounted on its bottom, 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 sides are machined into planes. This planar design is to match the geometry 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 smoothly. The guide slides smoothly back and forth within the guide groove 212, restricting all degrees of freedom except along the groove direction. The main body of the guide sliding assembly 227 is installed inside the housing 223 of the moving part connecting assembly. A limit mounting hole 224 is opened at one end of the moving part connecting assembly housing 223 near the ear clip mounting part 2225. A protruding limit structure 228 is provided on the outer wall of the guide sliding assembly 227. The limit structure 228 can be integrally formed with the body of the guide sliding assembly 227, or it can be fixed to its outer wall as an independent part by welding, bonding, or screws. The guide sliding assembly 227 is connected to the moving part connecting assembly. The assembly of the outer casing 223 is achieved through 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 assembly 227 from axially moving or rotating relative to the outer casing 223, so that the two are firmly combined into a whole motion unit. The most critical feature of the guide sliding assembly 227 is that a second thread structure 230 is machined on its inner wall. The direction of rotation of the second thread structure 230 is opposite to that of the first thread structure 2224 on the screw assembly 2221. It is this pair of oppositely oriented thread structures that mesh with each other, forming a combination of rotational motion and linear motion. In order to achieve low friction, the helical drive pair with mutual conversion of motion employs a special contact design: the cross-sectional shape of the thread teeth of the raised part of the second thread structure 230 matches the cross-sectional shape of the thread groove of the first thread structure 2224, so that when the two are meshed, they only contact at a single point on any cross-section. When considering the entire length of the thread teeth, this contact is that a ridge line of the raised part of the second thread structure 230, i.e., the contact line, contacts the concave surface of the first thread structure 2224, i.e., the groove surface. The second thread structure 230 slides along this contact line on the first thread structure 2224.

[0084] Supporting the second threaded structure 230: a component that meshes with the first thread 224 of the screw;

[0085] Install the movable guide block 229: transfer the linear motion constraint to the bottom guide rail;

[0086] Connecting moving part connecting component housing 223: It fixes itself to housing 223 by limiting structure 228 and limiting mounting hole 224, so that the movement of housing 223 is consistent with it.

[0087] The limiting structure 228 and the limiting mounting hole 224 provide a simple and reliable axial and circumferential positioning method, ensuring that there is no relative movement between the guide sliding assembly 227 and the moving part connecting assembly housing 223, thus forming a rigid motion unit. One-piece molding offers high strength; separate manufacturing may facilitate assembly or material selection.

[0088] When viewed from any cross-section perpendicular to the screw axis, the crest (protrusion) of the second thread 230 and the groove (concave surface) of the first thread 224 make contact at only one point. This is guaranteed by the specific arcuate cross-sectional profiles of both.

[0089] Line contact: When the entire thread is viewed along the screw axis, this point contact extends into a spatial curve (contact line) along the length of the thread. The crest line of the second thread 230 and the cogging surface of the first thread 224 form a continuous spatial line contact.

[0090] Reducing the contact area: Compared to 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, not the contact area. For sliding friction, especially in boundary lubrication or mixed lubrication conditions, reducing the contact area is crucial. Therefore, this line contact design can significantly reduce sliding friction resistance, thereby achieving low damping. Its effect is similar to that of a ball screw (point contact) being superior to a sliding screw (surface contact).

[0091] The limiting structure 228 and the guide sliding assembly 227 can also be connected by the following installation method: A waist-shaped mounting groove is provided on the outer wall of the guide sliding assembly 227. A spring is installed 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. A 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 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, the limiting structure 228 is pressed down, and then the guide sliding assembly 227 is inserted into the moving part connecting assembly housing 223. The limiting structure 228 is then installed in the limiting mounting hole 224. The spring pushes the limiting structure 228 out, at which point the limiting structure 228 is locked inside the limiting mounting hole 224, thus achieving a fixing effect.

[0092] The purpose of the detachable design is to provide a tool-free, quick assembly and disassembly solution. This is very convenient for cleaning, maintenance (such as cleaning the guide rail grooves and lubricating the threaded joints), or replacing the guide sliding assembly 227 and the moving guide block 229.

[0093] Steps to unlock by pressing:

[0094] 1. Finger pressure limiting structure 228;

[0095] 2. The spring is compressed, and at the same time the buckle disengages from the groove on the inner wall of the waist-shaped groove;

[0096] 3. The limiting structure 228 retracts into the waist-shaped groove;

[0097] 4. Insertion: Insert the guide sliding component 227 into the housing 223.

[0098] Spring-release locking procedure:

[0099] 1. When the limiting structure 228 is aligned with the limiting mounting hole 224 on the outer casing 223, release your finger;

[0100] 2. The spring will eject the limiting structure 228;

[0101] 3. The limiting structure 228 is embedded in the limiting mounting hole 224 (to achieve axial and circumferential limiting), and its buckle may spring back and engage with the slot in the inner wall of the waist-shaped groove (providing additional holding force to prevent it from wobbling in the hole 224).

[0102] Waist-shaped groove: provides space and guidance for the telescopic movement of the limiting structure 228.

[0103] Springs: provide both springing force and retaining force.

[0104] Slots / Snap-fits: Provide clear positioning points and auxiliary holding force on the telescopic path to prevent the limiting structure 228 from accidentally coming loose.

[0105] The preferred embodiments of this patent have been described in detail above. However, this patent is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this patent.

Claims

1. A low-damping, fast-speed spiral thread adjustment structure, characterized in that, include: Support components are used to support the overall structure and connect the dental tray posts to the dental 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: 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 achieve linear motion.

2. The low-damping, fast-speed spiral thread adjustment structure according to claim 1, characterized in that, The support components include: The outer casing covers the entire internal structure; The occlusal mounting assembly is fixed inside the upper part of the outer shell and is used to connect the dental tray posts; The scale structure is integrally formed with the outer shell and located at its top, with a scale embedded inside.

3. The low-damping, fast-speed spiral thread adjustment structure according to claim 2, characterized in that, The jaw support mounting assembly includes: Two mounting rod fixing plates, mounting back plate, fixing knob and mounting rod; The mounting rod passes through the circular mounting hole of the mounting rod fixing plate and the mounting back plate, with one end connected to the fixing knob and the other end adapted to the mounting hole of the dental tray post.

4. The low-damping, fast-speed spiral thread adjustment structure according to claim 1, characterized in that, The transmission assembly structure includes: The positioning component of the moving part has two sets of sliding guide rail grooves on its bottom surface; The ear clip fixing rod mounting position is located on both sides of the positioning component of the movable part; The mounting holes for the fixed plate are located on the upper end face of the positioning component of the moving part.

5. The low-damping, fast-speed spiral thread adjustment structure according to claim 1, characterized in that, The moving part of the ear clip power assembly includes: The transmission structure includes two sets of screw assemblies and a screw connection structure connecting the two. The screw assembly has an ear clip mounting part at its end and a first thread structure on its outer wall.

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

7. The low-damping, fast-speed spiral thread adjustment structure according to claim 1, characterized in that, The moving part further includes: The moving part connecting component housing is sleeved onto the outside of the screw assembly; A guide sliding assembly is located inside the housing of the moving part connecting assembly, and its inner wall is provided with a second thread structure that rotates in the opposite direction to the first thread structure.

8. The low-damping, fast-speed spiral thread adjustment structure according to claim 7, characterized in that, The second thread structure and the first thread structure form a line contact pair: It forms a single-point contact on any cross-section, and in three-dimensional space, it forms a continuous line contact between the raised edge and the concave surface.

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

10. The low-damping, fast-speed spiral thread adjustment structure according to claim 7, characterized in that, The outer shell of the guide sliding assembly and the moving part connection assembly is fixed by 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 assembly and locked by a spring and a buckle mechanism.

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

12. The low-damping, fast-speed spiral thread adjustment structure according to claim 1, characterized in that, The ear clip spacing of the spiral assembly is adjusted by pulling the ear clips simultaneously with both hands, driving the moving part to move relative to the outer shell of the connecting assembly and the transmission structure. The reverse thread pair converts the linear input into the synchronous rotation of the twin screws.

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

14. The low-damping, fast-speed spiral thread adjustment structure according to claim 5, characterized in that, The screw connection structure of the transmission structure is equipped with a rotating bearing, and its outer wall is interference-fitted with the inner wall of the transmission component structure.

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