Height adjusting, limiting and fixing structure of head positioning device

Abstract

The invention discloses a height adjusting, limiting and fixing structure of a head positioning device, which comprises a base assembly and a support rod assembly, and the base assembly is fixed on a forehead main body bracket and comprises a guide part for providing a linear reference and a limiting part for limiting the lifting limit; the supporting rod assembly is in sliding fit with the base assembly and comprises a movable carrier, a transmission mechanism and a locking mechanism, and the movable carrier is used for installing the locking structure. According to the other scheme, the base assembly is provided with a second guide rod and a gear clamping groove plate, and the supporting rod assembly comprises a special-shaped cam and a reset spring and is matched with an operation handle to achieve unlocking and locking. Through cooperation and synchronization of the components, the functions of height adjustment, arbitrary locking and limit protection are achieved, operation is easy and convenient, the adjustment precision is high, safety and reliability are high, and the device is suitable for clinical head positioning scenes.

Description

Technical Field

[0001] This invention relates to a positioning structure, specifically to a height adjustment and limiting fixing structure for a head positioning device. Background Technology

[0002] Head positioning devices, as key auxiliary equipment in neurosurgery, radiotherapy, and imaging examinations, function to provide stable and precise fixation support for the patient's head, ensuring positional accuracy and safety during medical procedures. In clinical applications, head positioning devices need to adapt to different patient head sizes, surgical positions, and operational requirements; therefore, height adjustment functionality is one of the core performance indicators of such devices. In existing technologies, head positioning devices typically employ mechanical height adjustment mechanisms. These mechanisms utilize the cooperation of guide rods and sliding components to achieve vertical displacement of the locking structure, which, in conjunction with a locking mechanism, fixes the height at a specific position. Such mechanisms generally consist of a base, guide components, movable rods, and locking components. The operator manually applies external force to drive the movable components along the guide path, and once the target height is reached, the locking mechanism fixes the position, thus meeting the head positioning needs in different clinical scenarios.

[0003] However, in existing technologies, height adjustment mechanisms cannot simultaneously achieve both adjustment flexibility and structural safety in practical applications, resulting in the dual challenges of insufficient height positioning accuracy and lack of structural protection mechanisms in clinical operations. Summary of the Invention

[0004] The purpose of this invention is to provide a head positioning device to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: According to one aspect of the present invention, a height adjustment and limiting fixing structure for a head positioning device includes: a base assembly fixedly installed on the forehead support of the head positioning device, including a guide component and a limiting component, the guide component providing a linear reference for height adjustment, the limiting component for limiting the extreme position of lifting and lowering; a support rod assembly slidingly engaged with the base assembly to achieve lifting and lowering; and a movable carrier, a transmission mechanism, and a locking mechanism, the movable carrier for mounting the locking structure of the head positioning device, the transmission mechanism for transmitting lifting and lowering power to cause the support rod assembly to reciprocate along the guide component, the locking mechanism cooperating with the transmission mechanism to lock the support rod assembly at any position, and the limiting component cooperating with the support rod assembly to prevent excessive lifting and lowering from causing structural damage. The three components work together to achieve height adjustment, limiting, and fixing of the locking structure.

[0006] According to at least one embodiment of the present invention, the height adjustment and limiting fixing structure of the head positioning device includes a guide component comprising a first guide rod mounting seat and a first guide rod, wherein the first guide rod mounting seat is provided with a precision guide hole, the first guide rod is fixed to the precision guide hole, the limiting component is a rigid boss integrally formed on the upper end of the first guide rod mounting seat, the top surface of the boss is provided with an elastic buffer pad, the base assembly is a third support base, and the forehead support main bracket is a third forehead support main bracket.

[0007] According to at least one embodiment of the present invention, the height adjustment and limiting fixing structure of the head positioning device includes a transmission mechanism comprising a gear and rack structure, the rack structure being disposed on one side of the first guide rod; a locking mechanism comprising a ratchet mounting structure, a ratchet, and a torsion spring; the ratchet mounting structure being a U-shaped groove, the ratchet being pivotally mounted on the U-shaped groove via a pin; and the torsion spring being sleeved on the pin, so that the ratchet teeth of the ratchet and the tooth groove of the gear engage unidirectionally to achieve reverse anti-reverse; the support rod assembly being a third support rod; and the movable carrier comprising an alignment structure and a first support slide rod.

[0008] According to at least one embodiment of the present invention, the height adjustment and limiting fixing structure of the head positioning device includes a base assembly that is an independently formed metal structural component (third support base), which is fixed to the forehead support main bracket (third forehead support main bracket) by bolts, welding or pin positioning. The metal structural component is L-shaped, T-shaped or flat with flange structure. The support rod assembly (third support rod) is connected to the locking structure through a locking part mounting joint.

[0009] According to at least one embodiment of the present invention, the height adjustment and limiting fixing structure of the head positioning device is provided, wherein the transmission mechanism is replaced by a ball screw pair, the guide component is replaced by a ball screw, the gear in the transmission mechanism is replaced by a screw nut, the support rod assembly (third support rod) is fixedly connected to the screw nut, the ball screw pair includes a ball screw, a screw nut and a circulating ball assembly, the ball screw is axially installed in the precision guide hole of the guide component (first guide rod mounting seat), and both ends are supported by angular contact ball bearings, the base assembly is a third support base, and the forehead bracket is a third forehead bracket.

[0010] According to at least one embodiment of the present invention, the height adjustment and limiting fixing structure of the head positioning device replaces the locking mechanism with a one-way clutch. The inner ring of the one-way clutch is interference-fitted with the gear shaft, and the outer ring is fixed to the inner wall (inner wall of the first support slide rod) of the support rod assembly (third support rod). The reverse stop of the transmission mechanism (gear and rack structure) is realized through the one-way locking function. The base assembly is the third support base, and the forehead bracket is the third forehead bracket.

[0011] According to another aspect of the present invention, a height adjustment and limiting fixing structure for a head positioning device includes: a base assembly, which is a fourth support base and is fixedly installed on a fourth forehead support body bracket. The base assembly includes a second guide rod as a guide component and a gear slot plate fixed to the top of the second guide rod. The gear slot plate has regularly distributed slots on its side. A support rod assembly, which is a fourth support rod and slides with the second guide rod, includes a movable carrier, a transmission mechanism, and a locking mechanism. The movable carrier includes a buffer protection structure sleeved on the outside of the second guide rod and a second support slide rod. The transmission mechanism is a shaped cam. The locking mechanism is a return spring. The shaped cam is installed on a positioning bushing via a rotating shaft. Its outer contour is divided into a locking section and a sliding section. The return spring is sleeved on the rotating shaft. In the initial state, it drives the locking section of the shaped cam to engage with the slots of the gear slot plate.

[0012] According to at least one embodiment of the present invention, the height adjustment and limiting fixing structure of the head positioning device is provided, wherein the irregular cam is replaced by an eccentric wheel, the gear slot plate is replaced by a continuous ratchet guide rail, the eccentric wheel is locked by meshing with the ratchet guide rail under the action of the return spring, the base assembly is a fourth support base, the forehead support main bracket is a fourth forehead support main bracket, and the support rod assembly is a fourth support rod.

[0013] According to at least one embodiment of the present invention, the height adjustment and limiting fixing structure of the head positioning device includes a gear slot plate replaced by a guide rod with an annular groove, a shaped cam replaced by a steel ball and compression spring assembly, wherein the steel ball is embedded in the annular groove under the preload of the compression spring to achieve locking, the base assembly is a fourth support base, the forehead support main bracket is a fourth forehead support main bracket, the support rod assembly is a fourth support rod, and the movable carrier includes a buffer protection structure and a second support slide rod.

[0014] According to at least one embodiment of the present invention, the height adjustment and limiting fixing structure of the head positioning device further includes an operating handle, the operating handle being connected to the rotating shaft of the irregular cam, the unlocking turning angle of the operating handle being 30° to 45°, the lifting speed of the support rod assembly (fourth support rod) being 50–80 mm / s, the buffer protection structure having a built-in rubber buffer ring, the base assembly being a fourth support base, and the forehead support main bracket being a fourth forehead support main bracket.

[0015] Compared with the prior art, the beneficial effects of the present invention are: This invention, through the coordinated design of the base assembly, support rod assembly, transmission mechanism, and locking mechanism, simultaneously achieves three core functions—height adjustability, arbitrary locking, and extreme protection—without increasing operational complexity: the guide component provides a high-precision linear reference, ensuring that the locking structure is always in the predetermined posture, preventing swaying, tilting, or shaking from affecting the accuracy of head positioning; the limiting component and elastic buffer pad work together to achieve a flexible mechanical stop at the descent limit, absorbing impact energy and avoiding structural damage caused by hard collisions; the cooperation between the transmission mechanism and the locking mechanism enables smooth lifting and instant locking, improving adjustment accuracy and operational safety, and significantly enhancing the reliability and clinical applicability of the device. Attached Figure Description

[0016] Figure 1 This is an overall assembly structure diagram of the basic head positioning device according to an embodiment of the present invention; Figure 2 This is an enlarged view of the forehead structure of the basic head positioning device according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the cooperation between the support structure and the locking structure of the basic head positioning device according to an embodiment of the present invention; Figure 4 This is an overall assembly structure diagram of a head positioning device with dual-sided independent adjustment and end-adaptive fitting according to an embodiment of the present invention. Figure 5 This is a detailed diagram of the support structure angle adjustment and limiting structure of the head positioning device with dual-sided independent adjustment and end adaptive fitting according to an embodiment of the present invention. Figure 6 This is a schematic diagram of the distributed pressing unit of the locking structure of the head positioning device with dual-sided independent adjustment and end adaptive fitting according to an embodiment of the present invention; Figure 7 This is an overall assembly structure diagram of a self-locking precision linear lifting head positioning device according to an embodiment of the present invention. Figure 8 This is a detailed structural diagram of the third support base of the self-locking precision linear lifting head positioning device according to an embodiment of the present invention; Figure 9 This is a detailed view of the external structure of the third support rod of the self-locking precision linear lifting head positioning device according to an embodiment of the present invention. Figure 10 This is an anatomical diagram of the internal gear-ratchet self-locking transmission system of a self-locking precision linear lifting head positioning device according to an embodiment of the present invention. Figure 11 This is a schematic diagram of the overall locking structure of the self-locking precision linear lifting head positioning device according to an embodiment of the present invention; Figure 12 This is a schematic diagram of the head buffer pad and the second connecting beam assembly of a self-locking precision linear lifting head positioning device according to an embodiment of the present invention. Figure 13 This is a detailed diagram showing the connection between the second buffer connector and the second clamping rod of a self-locking precision linear lifting head positioning device according to an embodiment of the present invention. Figure 14 This is an overall structural diagram of the head positioning device for adjusting and locking the irregular cam and slot plate according to an embodiment of the present invention. Figure 15 This is a detailed structural diagram of the fourth support base of the head positioning device with an adjustable locking mechanism for irregularly shaped cams and slot plates according to an embodiment of the present invention. Figure 16 This is an anatomical diagram of the internal irregular cam structure of the fourth support rod of the head positioning device for adjusting and locking irregular cam and slot plate according to an embodiment of the present invention. Figure 17 This is a schematic diagram of the cam-slot locking structure of the head positioning device for adjusting and locking the irregular cam and slot plate according to an embodiment of the present invention; Figure 18 This is a detailed drawing of the locking structure of the head positioning device for adjusting and locking the irregular cam and slot plate according to an embodiment of the present invention.

[0017] 123. Third-tier main support frame 133. Fourth Grade Main Support 221. Third Support Base 2211. First guide rod mounting base 2212. Limiting Structure 2213, First Guide Rod 222. Third support rod 2221. First support slide bar 2222 Locking part mounting joint 2224. Parallel Structure 2225. Ratchet mounting structure 2226. Ratchet 2227. Gear 231. Fourth Support Base 2312, Second Guide Rod 2313, Gear Slot Plate 232. Fourth support rod 2321. Second support slide bar 2322. Buffer Protection Structure 2323, Irregularly Shaped Cam 3. Locking structure 323. Second connecting beam Detailed Implementation The head positioning device of the present invention will be described in detail below with reference to the accompanying drawings. Those skilled in the art will understand that the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0018] Example 1 This invention addresses the problems of inflexible height adjustment of the locking structure, lack of limit protection, and susceptibility to structural damage due to excessive lifting and lowering in existing head positioning devices, thereby improving adjustment accuracy and operational safety.

[0019] This application provides a height adjustment and limiting fixing structure for a head positioning device, including: The base assembly is fixedly installed on the forehead support of the head positioning device, and includes a guide component and a limiting component. The guide component provides a linear reference for height adjustment, and the limiting component is used to limit the extreme positions of lifting and lowering. The support rod assembly slides with the base assembly to achieve lifting, and includes a movable carrier, a transmission mechanism and a locking mechanism. The movable carrier is used for the locking structure of the head positioning device. The transmission mechanism is used to transmit lifting power, causing the support rod assembly to reciprocate along the guide component; the locking mechanism works with the transmission mechanism to lock the support rod assembly at any position; the limiting component works with the support rod assembly to prevent excessive lifting and lowering from causing structural damage, and together they realize the height adjustment, limiting and fixing of the locking structure.

[0020] When the operator applies an upward pulling force, the transmission mechanism drives the support rod assembly to rise along the guide component. The locking mechanism releases its constraint during the movement, and after reaching the target height, it releases the external force. The locking mechanism automatically resets and engages the transmission mechanism to achieve a temporary height hold. When the operator applies downward pressure, the support rod assembly descends in a controlled manner until the limit component contacts the support rod assembly, forming a rigid or elastic mechanical stop to prevent further descent. Throughout the process, the guide component continuously provides a high-precision linear reference, ensuring that the locking structure is always in the predetermined posture, avoiding the impact of swaying, tilting, or shaking on the accuracy of head positioning. The three functions work together to simultaneously achieve the three core functions of height adjustment, arbitrary locking, and extreme protection without increasing the complexity of operation, significantly improving the reliability, safety, and clinical applicability of the device.

[0021] Example 2 In an optional embodiment, this application also provides a height adjustment limiting and fixing structure, wherein the third support base 221 is a base assembly, the third forehead support main bracket 123 is a forehead support main bracket, the guiding component includes a first guide rod mounting seat 2211 and a first guide rod 2213, and the limiting component is a limiting structure 2212; The support rod assembly is a third support rod 222, the movable carrier includes an alignment structure 2224 and a first support slide rod 2221, the transmission mechanism includes a gear 2227 and a rack and pinion structure, and the locking mechanism includes a ratchet mounting structure 2225, a ratchet 2226 and a torsion spring. The first guide rod mounting base 2211 has a precision guide hole, the first guide rod 2213 is fixed in the precision guide hole, and the rack structure is located on one side of the first guide rod 2213; the alignment structure 2224 is sleeved on the outside of the first guide rod 2213, and the first support slide rod 2221 has a gear mounting base and a ratchet mounting cavity inside. The gear 2227 is mounted on the gear mounting base through a bearing and meshes with the rack structure; the ratchet mounting structure 2225 is a U-shaped groove, and the ratchet 2226 is pivotally mounted on the U-shaped groove through a pin. The torsion spring is sleeved on the pin, so that the ratchet teeth of the ratchet 2226 mesh with the tooth groove of the gear 2227 in one direction to achieve reverse anti-reverse.

[0022] The third support base 221 is an independently formed metal structural component, used as a reference installation platform for the entire height adjustment and limiting fixing structure. It is fixed to the pre-reserved mounting holes or mounting surfaces on the upper end of the third bracket main body 123 by bolts or welding. The structural layout and size of the third support base 221 are adapted to the overall spatial constraints of the head positioning device. Its specific shape, thickness and reinforcing rib arrangement can be set according to actual assembly requirements. For example, it can be an L-shaped, T-shaped or flat plate with flange structure. This application embodiment does not make any special limitations on this.

[0023] The limiting structure 2212 is a rigid boss integrally formed on the upper end of the first guide rod mounting base 2211. The height of the boss precisely corresponds to the lowest working position of the third support rod 222, which is used to limit the descent limit of the support rod assembly. An elastic buffer pad made of polyurethane is bonded or embedded on the top surface of the boss. When the third support rod 222 descends to its limit, the buffer pad contacts the alignment structure 2224 to absorb impact energy and avoid hard metal collision. The geometric shape of the limiting structure 2212 can be a rectangular, circular or polygonal boss. Its stiffness and the combined stiffness of the buffer pad must meet the controllability of deformation under instantaneous impact load. The specific shape, installation method and buffer pad thickness tolerance of this application embodiment are not specifically limited.

[0024] The third support rod 222 is a movable part that bears and transmits the load of the locking structure 3. The third support rod 222 is connected to the locking structure 3 through a locking part mounting joint 2222. The joint can be a threaded interface, a snap-fit ​​structure or a quick-release pin structure. The embodiments of this application do not impose special limitations on its connection form and mechanical strength.

[0025] The third support base 221 and the third bracket main support 123 form a stable installation foundation. The first guide rod mounting seat 2211 and the first guide rod 2213 together provide a high-precision linear guide reference. The limiting structure 2212 and the buffer pad work together to achieve a flexible mechanical stop at the lowering limit. The alignment structure 2224 and the first guide rod 2213 work together to ensure the stability of movement during the lifting process. The gear 2227 meshes with the rack structure to achieve smooth and efficient power transmission. The ratchet 2226 meshes with the gear 2227 in one direction under the preload of the torsion spring, and automatically responds to the reverse rotation trend to complete the anti-reverse locking.

[0026] Example 3: In an optional embodiment, this application also provides a highly up-adjusting operation step including: Step 1: The operator pulls the locking structure 3 or the second connecting beam 323 upwards, applying an upward pulling force of 5-10N; The upward pulling force of 5-10N refers to the range of vertically upward static pulling force applied by the operator to the locking structure 3 or the second connecting beam 323. This pulling force must be sufficient to overcome the weight component of the third support rod 222 and the components it supports, the sliding friction resistance between the first guide rod 2213 and the alignment structure 2224, and the rolling resistance at the meshing point of the gear 2227 and the rack structure. This pulling force value has been experimentally calibrated to ensure that the gear 2227 can reliably start and move smoothly upward along the rack while ensuring ease of operation. It avoids slippage or delayed response due to insufficient pulling force, and also avoids unexpected plastic deformation of the ratchet 2226 or over-compression of the torsion spring due to excessive pulling force. In one optional implementation, the pulling force can be provided with tactile feedback elastic element integrated into the bottom of the locking structure 3. In another optional implementation, the pulling force range corresponds to the physiological output range when the human thumb and forefinger naturally lift, and can be stably reproduced without additional force measuring devices.

[0027] Step 2: The pulling force is transmitted to the gear 2227 through the first support slide bar 2221. The gear 2227 rolls upward along the rack of the first guide rod 2213, the ratchet teeth of the ratchet 2226 are lifted, and the torsion spring is compressed. Specifically, "gear rising along the rack" refers to gear 2227, driven by tension, maintaining meshing with the rack structure on one side of the first guide rod 2213 at its pitch circle, and performing pure rolling motion along the length of the rack. Its axis remains parallel to the axis of the first guide rod 2213, and its trajectory is guided and constrained by the first guide rod 2213 and the alignment structure 2224, resulting in no lateral deviation. "Ratchet being lifted" refers to gear 2227, during forward rolling, having its tooth groove leading edge contacting and pushing the ratchet 2226, causing the ratchet 2226 to rotate slightly counterclockwise around the pin shaft to face the gear axis, thus disengaging from the meshing state with the tooth groove of gear 2227. "Torsion spring compression" refers to this action simultaneously causing... The torsion spring fitted on the pin undergoes angular compression deformation, storing elastic potential energy to provide restoring torque for subsequent reset. In one optional implementation, the rolling action can be achieved by decomposing the normal meshing force between the gear 2227 and the rack structure: the tension is converted into the axial support reaction force and tangential driving force of the gear via the first support slide 2221, thereby driving the rolling. In another optional implementation, the action can also be achieved by setting a preloaded elastic coupling section in the first support slide 2221 to absorb the initial lifting impact and smoothly transmit power. Furthermore, the action can also be achieved by adding a guide slope to the end face of the gear 2227, so that radial clearance occurs at the initial contact of the ratchet, reducing the critical force required for lifting.

[0028] Step 3: Continue lifting to the target height. You can stop lifting at any time during the process. Gear 2227 will remain stationary to temporarily hold the height. The "height hold" refers to the fact that after the upward pulling force is stopped at any intermediate position, gear 2227 immediately stops rotating, and the third support rod 222 remains in its current position without sliding down or rebounding. This characteristic relies on the ratchet 2226 always having a tendency to engage with gear 2227 under the preload of the torsion spring, but the ratchet only completes the engagement action when gear 2227 has a downward rotation tendency. At the instant of lifting and pausing, gear 2227 is in a state of dynamic equilibrium, and the tooth surface friction and structural static friction jointly maintain instantaneous locking. This hold capability does not depend on... The external braking mechanism or electronic control unit is entirely self-consistent with the mechanical structure. In one alternative implementation, the temporary holding stability can be enhanced by improving the matching degree between the surface roughness of the rack teeth and the hardness of the gear teeth. In another alternative implementation, a low-migration grease can be coated on the surface of the first guide rod 2213 to balance the smoothness of movement and the damping of the stop. Furthermore, the temporary holding function can also be assisted by the 0.03–0.05 mm fitting gap set between the alignment structure 2224 and the first guide rod 2213 to form a wedge-shaped self-locking effect in a slightly tilted state.

[0029] Step 4: Release the tension, and gear 2227 will have a slight downward rotation tendency. The torsion spring will return to its original position, and the ratchet teeth of ratchet 2226 will engage with the tooth grooves of gear 2227, completing the upward adjustment and self-locking. The automatic locking after release refers to the situation where, after the operator completely removes the upward pulling force, the weight of the third support rod 222 and the components it supports acts on the axis of gear 2227 through the first support slide rod 2221. This creates a slight clockwise rotation of gear 2227 around its own axis, causing it to face the direction of the gear axis when viewed. This slight rotation is extremely small, usually less than 0.5°, but sufficient to trigger the torsion spring to release the stored elastic potential energy, driving the ratchet 2226 to swing clockwise around the pin, causing its ratchet teeth to re-engage with the adjacent tooth slots of gear 2227, forming a one-way mechanical anti-reverse action. This locking action is audible. The response time is ≤0.3s, and the anti-slip load after locking is ≥150N. In one optional implementation, the locking process can improve the meshing stiffness and impact resistance by optimizing the ratchet tooth profile, such as by using an involute profile. In another optional implementation, a micro-protrusion can be set at the root of the ratchet tooth of the ratchet 2226 to form a secondary limit with the bottom surface of the tooth groove of the gear 2227, preventing the meshing depth from decaying after long-term use. Furthermore, the locking action can also be combined with the magnetic damping ring set at the end of the first guide rod 2213 to apply controllable eddy current damping to the micro-rotation trend of the gear 2227, so as to avoid locking impact.

[0030] Example 4: In an optional embodiment, this application also provides a height reduction operation step including: Step 1: The operator gently presses down on the locking structure 3 or the second connecting beam 323, applying a downward pressure of 5-8N; The downward pressure of 5-8N refers to the vertically downward controllable mechanical force applied by the operator to the locking structure 3 or the second connecting beam 323 through their fingers or palm. Its numerical range has been experimentally verified to ensure operational sensitivity while avoiding accidental triggering or overloading. This pressure serves as the initiation condition and driving force input for the downward adjustment action, acting directly on the first support slide 2221 and then transmitting it to the gear 2227. The locking structure 3 is a rigid component in the head positioning device used to hold the patient's forehead, and it is fixedly connected to the third support rod 222. The second connecting beam 323 is a lateral force transmission component connecting the locking structure 3 and the third support rod 222, forming a force transmission path in their structure. This pressure value does not depend on external sensor feedback and can be stably achieved solely through human touch.

[0031] In one alternative implementation, the downward pressure can be applied by the operator pinching the two ends of the second connecting beam 323 with their thumb and forefinger and pressing vertically downwards. In another alternative implementation, the downward pressure can be applied by placing the palm flat on the top of the locking structure 3 and applying stable pressure using the weight of the forearm in conjunction with a slight elbow flexion. Furthermore, the downward pressure can also be applied by using an auxiliary pressing block—which has an ergonomic arc-shaped contact surface and is temporarily attached to the surface of the locking structure 3 by magnetic attraction—to reduce local pressure and improve pressure control accuracy.

[0032] This application limits the downward pressure range to 5-8N, enabling gear 2227 to obtain sufficient driving force to overcome static friction and start descending. At the same time, it avoids instantaneous overload deformation of ratchet 2226 or plastic failure of torsion spring due to excessive pressure, thereby ensuring transmission smoothness and mechanism life.

[0033] Step 2: The pressure drives the gear 2227 to roll downwards along the rack, and the ratchet teeth of the ratchet 2226 are continuously pushed up, causing the torsion spring to be repeatedly compressed and reset. Specifically, the downward rolling of gear 2227 along the rack refers to the clockwise rotation of gear 2227 relative to the rack on the first guide rod 2213 under downward pressure, with its axis as the center, so that it faces the rack when viewed from the front. The rack structure is located on one side of the first guide rod 2213, and gear 2227 maintains a constant meshing state with it. The continuous lifting of the ratchet teeth of ratchet 2226 means that every time gear 2227 rotates by one tooth pitch, the edge of its tooth groove pushes the unidirectional ratchet teeth of ratchet 2226 to swing slightly around the pin shaft, causing the ratchet teeth to disengage from the current meshing position. The repeated compression and reset of the torsion spring means that the torsion spring periodically undergoes angular compression and elastic rebound with each swing of ratchet 2226. Its angular deformation is linearly related to the gear rotation angle and is within the elastic deformation range throughout the entire process.

[0034] In one optional implementation, the gear rolls downward along the rack by converting the downward pressure into gear axial torque through the first support slide 2221, which is then transmitted to the gear 2227 body via a deep groove ball bearing to drive it to continuously mesh and roll. In another optional implementation, the gear rolls downward along the rack by providing an annular friction band on the end face of the gear 2227, which generates auxiliary radial constraint by contacting the elastic pressure plate preset on the inner wall of the first support slide 2221, thereby suppressing the axial movement of the gear. Furthermore, the gear can also roll downward along the rack by coating the rack surface with a low-friction coefficient solid lubricant coating to reduce rolling resistance and tooth surface wear.

[0035] This application utilizes the meshing and rolling of gear 2227 and rack in conjunction with the periodic lifting action of ratchet 2226 to decompose continuous downward displacement into discrete, controlled micro-stepping motions. This not only prevents the support rod assembly from accelerating downward due to its own weight, but also provides a precise position response basis for subsequent mechanical stops.

[0036] Step 3: The third support rod 222 descends to the buffer pad of the limiting structure 2212, and the alignment structure 2224 contacts the buffer pad to create a mechanical stop, and the operator stops applying pressure; The descent of the third support rod 222 to the buffer pad of the limiting structure 2212 refers to the axial downward movement of the third support rod 222 along the first guide rod 2213 until its integrated alignment structure 2224 moves to a position where it physically contacts the polyurethane elastic buffer pad on the top surface of the limiting structure 2212. The mechanical stop generated by the contact between the alignment structure 2224 and the buffer pad means that the front plane of the brass alignment structure 2224 makes surface contact with the surface of the buffer pad. The buffer pad undergoes 3-5mm elastic deformation under pressure, absorbing the impact kinetic energy and forming a rigid end point of the stroke. This contact state constitutes an insurmountable physical boundary, preventing the third support rod 222 from continuing to descend, which could lead to interference with the bottom structure of the first guide rod 2213 or disengagement of the gear 2227. The operator stopping the application of pressure is the sign that this step is complete. The timing of this action is determined by the operator based on tactile feedback and does not require additional detection devices.

[0037] This application achieves precise spatial matching between the limiting structure 2212 and the alignment structure 2224, and combines the elastic energy dissipation characteristics of the buffer pad to simultaneously realize the triple functions of stroke termination, impact buffering and operation prompt in the mechanical stop, effectively avoiding structural damage and noise caused by hard collisions.

[0038] Step 4: After releasing the pressure, the ratchet 2226 engages with the gear teeth under the action of the torsion spring, thus locking the ratchet after adjustment. Here, "pressure release" refers to the operator removing the downward pressure applied to the locking structure 3 or the second connecting beam 323. At this time, the third support rod 222 is only affected by its own weight and the residual inertia of the system. "Ratchet 2226 engaging with the gear teeth under the action of the torsion spring" means that the torsion spring, driven by its stored elastic potential energy, drives the ratchet 2226 to swing back around the pin shaft, so that its one-way ratchet teeth fall back into the adjacent teeth of the gear 2227, completing the one-way meshing reset. This engaging action occurs within 50–100 ms after pressure release, with a rapid response and no rebound gap.

[0039] In one alternative implementation, the ratchet can be embedded in the gear tooth groove by a torsion spring driving the ratchet 2226 to swing back with a constant preload, and automatically aligning by relying on the self-guiding characteristics of the ratchet geometry and the tooth groove profile. In another alternative implementation, the ratchet can be embedded in the gear tooth groove by adding a rounded chamfer to the end of the ratchet teeth of the ratchet 2226 to reduce the peak contact stress during the embedding process. Furthermore, the ratchet can be embedded in the gear tooth groove by setting a shallow groove at the bottom of the tooth groove of the gear 2227, allowing the ratchet tip to sink slightly, thereby enhancing meshing stability.

[0040] This application uses a torsion spring to drive the ratchet 2226 to complete the engagement and reset at the moment of pressure release, so that the gear 2227 immediately loses the reverse rotation degree of freedom, thereby rigidly fixing the third support rod 222 at the lowering termination position, ensuring the certainty and repeatability of the height adjustment result.

[0041] Example 5: In an optional embodiment, this application also provides a transmission mechanism that can be replaced with a ball screw pair, where the first guide rod 2213 is replaced with a ball screw, the gear 2227 is replaced with a screw nut, and the third support rod 222 is fixedly connected to the screw nut, cooperating with the ratchet 2226 and a torsion spring to achieve self-locking. The ball screw pair includes a ball screw, a screw nut, and a circulating ball assembly. The ball screw replaces the original first guide rod 2213 and is axially installed in the precision guide hole of the first guide rod mounting seat 2211. Both ends are supported on the inner wall of the mounting base by angular contact ball bearings to ensure axial and radial positioning accuracy; the ball screw has a lead of 2–4 mm, a thread accuracy grade of C3, a surface roughness Ra≤0.4 μm, and a hardness of HV900 or higher after nitriding treatment; the screw nut is made of high-rigidity bronze-based powder metallurgy material, with a double-row circulating raceway inside, which cooperates with the ball screw to form a preloaded backlash-free transmission structure. The preload can be set to 50–150 N according to the actual load to eliminate reverse backlash.

[0042] Example 10: In an optional embodiment, this application also provides a locking mechanism that can be replaced by a one-way clutch, wherein the inner ring of the one-way clutch is interference-fitted with the gear shaft, and the outer ring is fixed to the inner wall of the first support slide 2221, thereby achieving reverse locking of the gear 2227 through the one-way locking function.

[0043] The one-way clutch is a mechanical one-way overrunning clutch. Its internal structure includes an outer ring, an inner ring, rollers or wedges, a cage, and a return spring. The inner ring is connected to the gear shaft by an interference fit, with the interference amount set to 0.01–0.03 mm according to the gear shaft diameter to ensure that no relative rotation occurs when transmitting torque. The outer ring is fixed to the annular mounting step on the inner wall of the first support slide 2221 by set screws or laser welding. When the gear 2227 is subjected to gravity or external load and has a downward rotation tendency (i.e., reverse rotation), the rollers wedge into the locking gap between the inner and outer rings under the action of friction and the inclined plane, forming a rigid self-locking mechanism. When the upward lifting operation is performed, the gear rotates in the forward direction, and the rollers roll along the inclined plane to release the gear. The inner ring rotates freely relative to the outer ring, achieving resistance-free lifting and lowering.

[0044] Example 6: In one optional embodiment, this application also provides a height adjustment limiting and fixing structure, wherein the fourth support base 231 is a base assembly, the fourth front bracket main support 133 is a front bracket main support, the second guide rod 2312 is a guide component, and the limiting component is integrated into the transmission mechanism; The support rod assembly is the fourth support rod 232, the movable carrier includes a buffer protection structure 2322 and a second support slide rod 2321, the transmission mechanism includes a gear slot plate 2313 and a shaped cam 2323, and the locking mechanism is a return spring. The second guide rod 2312 is a stainless steel round tube. The gear slot plate 2313 is fixed to the top of the second guide rod 2312. The side has regularly distributed slots. The buffer protection structure 2322 is sleeved on the outside of the second guide rod 2312. The second support slide rod 2321 has a cam mounting cavity and a spring mounting hole inside. The irregular cam 2323 is mounted on the positioning bushing through a rotating shaft. The outer contour is divided into a locking section and a sliding section. The reset spring is sleeved on the rotating shaft. In the initial state, the locking section of the irregular cam 2323 is driven to mesh with the slot of the gear slot plate 2313.

[0045] The fourth support base 231 is an integral structural component made of metal casting or machining, used to rigidly connect and fix it to the reserved installation position on the upper end of the fourth bracket main body 133. Its installation method includes bolt fastening, pin positioning or welding fixation. The specific installation structure and tolerance fit can be set according to the actual assembly requirements. This application embodiment does not make special limitations on this.

[0046] Example 7: In an optional embodiment, this application also provides unlocking and height adjustment operation steps including: Step 1: Hold the operating handle and turn it 30 to 45 degrees in the unlocking direction to drive the irregular cam 2323 to rotate. The return spring is twisted and compressed, and the locking section is disengaged from the slot. The 30° to 45° rotation angle of the operating handle refers to the range of circumferential motion angles made by the operating handle around the rotating shaft of the irregular cam 2323. This angle setting takes into account both unlocking reliability and operating feel. If the angle is too small, the locking section may not completely disengage from the slot, while if the angle is too large, it will increase the structural redundancy stroke and operating fatigue. The unlocked state refers to the mechanical state in which the locking section of the irregular cam 2323 is completely disengaged from the slot of the gear slot plate 2313 and the sliding section forms surface contact with the inner wall of the slot. At this time, the axial movement resistance of the second support slide rod 2321 along the second guide rod 2312 is significantly reduced. The torsional compression of the return spring indicates that the return spring stores elastic potential energy. Its torsion amount is approximately linearly related to the rotation angle, providing driving force for subsequent automatic reset. The disengagement of the locking section from the slot is the condition for unlocking to be completed. It indicates that there is no meshing interference between the sawtooth contour of the locking section and the V-shaped or arc-shaped structure of the slot, allowing the second support slide rod 2321 to slide freely.

[0047] Step 2: Keeping the unlocked state, push the second support slide bar 2321 up and down to drive the locking structure 3 to rise and fall at a speed of 50-80mm / s to close to the target height; Maintaining the unlocked state means keeping the operating handle's rotation angle constant throughout the entire lifting process, ensuring that the locking section of the shaped cam 2323 remains disengaged from the slot. This state relies on the return spring not yet releasing its elastic potential energy. Pushing the second support slide rod 2321 up and down is the lifting action. Its thrust is transmitted to the rotating shaft of the shaped cam 2323 through the cam mounting cavity of the second support slide rod 2321. However, since the locking section has disengaged from the slot, this thrust does not trigger the locking function, but only drives the overall assembly to slide axially along the second guide rod 2312. A speed of 50–80 mm / s limits the rate of the lifting dynamic process. This speed range is set based on clinical operating habits and structural safety margins: speeds below 50 mm / s are prone to low adjustment efficiency, while speeds above 80 mm / s may cause instantaneous deformation of the rubber buffer ring of the buffer protection structure 2322 to exceed the limit or guide instability. Approaching the target height means that the lifting termination point does not need to be precisely positioned to a certain scale, but rather a positional tolerance within ±2 mm is allowed, with final positioning completed in subsequent steps.

[0048] Step 3: Release the operating handle, the reset spring returns to its original position, the irregular cam 2323 rotates in the opposite direction, and the locking section engages with the corresponding slot to achieve instant locking; Specifically, releasing the operating handle means releasing the torque constraint applied to the finger, allowing the operating handle to rotate freely under the restoring force of the return spring; the return spring reset means that the return spring returns from the compressed state to the initial torsional angle, releasing the stored elastic potential energy. The time constant of this process is ≤0.3s, ensuring timely locking response; the reverse rotation of the irregular cam 2323 is a direct manifestation of the driving force of the return spring. Its rotation direction is opposite to the above-mentioned turning direction, and its rotation angle is basically equal to the above-mentioned turning angle; the locking section is embedded in the corresponding slot means that the locking section of the irregular cam 2323 re-enters the slot currently aligned with the gear slot plate 2313. The anti-slip texture on the inner wall of the slot and the serrations of the locking section form a mechanical engagement. This embedding action has self-aligning characteristics and does not rely on manual correction by the operator; instant locking means that the time interval from releasing the operating handle to the locking section being fully embedded in the slot is ≤0.5s, and after locking, the second support slide rod 2321 has no visible displacement under a rated load ≤150N.

[0049] Example 8: In an optional embodiment, this application also provides the following steps for temporary locking and fine-tuning: Step 1: During the adjustment process, the operating handle can be released at any height, the irregular cam 2323 will automatically lock, and the fourth support rod 232 will be fixed; Among them, releasing the operating handle at any height means releasing the rotational force applied to the operating handle at any intermediate position during the lifting and lowering process of the fourth support rod 232, without relying on the preset height scale or limit point; automatic locking means that after the return spring loses the external torsional constraint, it immediately drives the irregular cam 2323 to rotate in the opposite direction, so that the locking section is re-embedded in the slot currently aligned with the gear slot plate 2313. This action does not require an additional triggering mechanism or manual maintenance; the function of this technical feature is to decouple the height adjustment process into two stages: continuous sliding and instant fixation, so that the operator can stop the movement at any time and maintain the current height stability when visually confirming the relative position of the locking structure 3 and the patient's head.

[0050] In one alternative implementation, the automatic locking method may be: the elastic potential energy stored in the reset spring is converted into torque at the moment the operating handle is released, driving the irregular cam 2323 to rotate at an angular velocity of ≥15° / s, so that the locking section completes engagement with the corresponding slot within ≤0.3s; In another alternative implementation, the automatic locking method can be: based on the geometric self-guiding effect between the sawtooth profile of the locking section of the irregular cam 2323 and the V-shaped structure of the slot, the locking section is guided to slide into and engage along the inclined surface of the slot during the initial rebound stage of the return spring; Furthermore, the automatic locking method can also employ the following: a damping ring is installed inside the second support slide bar 2321 to buffer the slight wobbling of the irregular cam 2323 shaft, preventing the locking section from temporarily dislodging due to vibration, thereby improving locking reliability.

[0051] Step 2: When fine-tuning is required, turn the operating handle again to unlock, slide the second support slide bar 2321 up and down slightly, adjust to the optimal height, and then release the operating handle to complete the locking.

[0052] In one alternative implementation, the small sliding method can be: the operator gently pushes the outer wall of the second support slide bar 2321 with a single finger, and uses the controllable frictional resistance between the built-in rubber buffer ring of the buffer protection structure 2322 and the second guide rod 2312 to achieve a damped displacement in the range of 0.5–2 mm. Example 9: In one optional embodiment, this application also provides that the irregular cam 2323 can be replaced with an eccentric wheel, and the slot of the gear slot plate 2313 can be replaced with a continuous ratchet guide rail. The eccentric wheel engages with the ratchet guide rail under the action of the return spring to achieve locking; or the gear slot plate 2313 can be replaced with a guide rod with an annular groove, and the irregular cam 2323 can be replaced with a steel ball and a compression spring assembly. The steel ball is embedded in the annular groove under the action of the spring preload to achieve locking.

[0053] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A height adjustment limit fixing structure of a head positioning device, characterized by, The application relates to a head positioning device, which comprises a base assembly fixedly installed on a forehead body support of a head positioning device, a support rod assembly and a locking structure (3). The base assembly comprises a guide component and a limiting component, the guide component provides a linear reference for height adjustment, and the limiting component is used for limiting the lifting limit position. The support rod assembly is in sliding cooperation with the base assembly to realize lifting, and comprises a movable carrier, a transmission mechanism and a locking mechanism. The transmission mechanism is used for transmitting lifting power, so that the support rod assembly reciprocates along the guide component.

2. The height adjustment limit fixing structure according to claim 1, characterized by, The locking mechanism cooperates with the transmission mechanism to realize locking of the support rod assembly at any position.

3. The height adjustment limit fixing structure according to claim 2, characterized in that, The limiting component cooperates with the support rod assembly to prevent excessive lifting from causing structural damage.

4. The height adjustment limit fixing structure according to claim 2, characterized by The three components are cooperated to realize height adjustment, limiting and fixing of the locking structure (3). The guide component comprises a first guide rod mounting seat (2211) and a first guide rod (2213). The first guide rod mounting seat (2211) is provided with a precision guide hole. The first guide rod (2213) is fixed in the precision guide hole. The limiting component is a rigid boss integrally formed on the upper end of the first guide rod mounting seat (2211). The top surface of the boss is provided with an elastic buffer pad. The base assembly is a third support base (221). The forehead body support is a third forehead body support (123). The transmission mechanism comprises a gear (2227) and a rack structure. The rack structure is arranged on one side of the first guide rod (2213). The locking mechanism comprises a ratchet wheel mounting structure (2225), a ratchet wheel (2226) and a torsion spring. The ratchet wheel mounting structure (2225) is a U-shaped groove body. The ratchet wheel (2226) is pivotally installed on the U-shaped groove body through a pin shaft. The torsion spring is sleeved on the pin shaft. The teeth of the ratchet wheel (2226) are in one-way engagement with the tooth grooves of the gear (2227) to realize reverse locking. The support rod assembly is a third support rod (222). The movable carrier comprises a positioning structure (2224) and a first support sliding rod (2221). The base assembly is an independently formed metal structural member (third support base (221)). The metal structural member is fixed on the forehead body support (third forehead body support (123)) through bolt positioning, welding or pin positioning. The metal structural member has an L-shaped, T-shaped or flat plate flange structure. The support rod assembly (third support rod (222)) and the locking structure (3) are connected through a locking part mounting joint (2222).

5. The height adjustment limit fixing structure according to claim 1, wherein The transmission mechanism is replaced by a ball screw pair, the guide component is replaced by a ball screw, the gear in the transmission mechanism is replaced by a screw nut, the support rod assembly (third support rod (222)) is fixedly connected with the screw nut, the ball screw pair comprises a ball screw, a screw nut and a circulating ball assembly, the ball screw is installed in the precision guide hole of the guide component (first guide rod mounting seat (2211)) in the axial direction, and both ends are supported by angular contact ball bearings, the base assembly is a third support base (221), and the front cover main support is a third front cover main support (123).

6. The height adjustment stopper structure according to any one of claims 1 or 3, wherein The locking mechanism is replaced by a one-way clutch, the inner ring of the one-way clutch is in interference fit with the gear shaft, the outer ring is fixed to the inner wall (first support sliding rod (2221) inner wall) of the support rod assembly (third support rod (222)), and the reverse locking of the transmission mechanism (gear (2227) and rack structure) is realized through the one-way locking function, the base assembly is a third support base (221), and the front cover main support is a third front cover main support (123).

7. A height adjustment stop structure of a head positioning device, characterized by comprising: Comprise: The base assembly is a fourth support base (231) fixedly installed on a fourth front cover main support (133), the base assembly comprises a second guide rod (2312) as a guide component and a gear clamping groove plate (2313) fixed to the top of the second guide rod (2312), and the side surface of the gear clamping groove plate (2313) is provided with regularly distributed clamping grooves; The support rod assembly is a fourth support rod (232) in sliding fit with the second guide rod (2312) and comprises a movable carrier, a transmission mechanism and a locking mechanism, the movable carrier comprises a buffer protection structure (2322) sleeved on the outside of the second guide rod (2312) and a second support sliding rod (2321), the transmission mechanism is a special-shaped cam (2323), and the locking mechanism is a return spring; The special-shaped cam (2323) is installed on a positioning shaft sleeve through a rotating shaft, and the outer contour is divided into a locking section and a sliding section, the return spring is sleeved on the rotating shaft, and in the initial state, the locking section of the special-shaped cam (2323) is driven to be engaged with the clamping groove of the gear clamping groove plate (2313).

8. The height adjustment limit fixing structure according to claim 7, characterized in that, The special-shaped cam (2323) is replaced by an eccentric wheel, the gear clamping groove plate (2313) is replaced by a continuous ratchet guide rail, the eccentric wheel is engaged with the ratchet guide rail to realize locking under the action of the return spring, the base assembly is a fourth support base (231), the front cover main support is a fourth front cover main support (133), and the support rod assembly is a fourth support rod (232).

9. The height adjustment limit fixing structure according to claim 7, wherein The gear clamping groove plate (2313) is replaced by a guide rod with an annular groove, the special-shaped cam (2323) is replaced by a steel ball and compression spring assembly, the steel ball is embedded in the annular groove under the action of the compression spring pre-tightening force to achieve locking, the base assembly is a fourth support base (231), the frontal hair main body support is a fourth frontal hair main body support (133), the support rod assembly is a fourth support rod (232), and the movable carrier includes a buffer protection structure (2322) and a second support slide rod (2321).

10. The height adjustment limit fixing structure according to claim 7, wherein It also includes an operating handle connected with the rotating shaft of the special-shaped cam (2323), the unlocking screwing angle of the operating handle is 30-45°, the lifting speed of the support rod assembly (fourth support rod (232)) is 50-80 mm / s, and the buffer protection structure (2322) is internally provided with a rubber buffer ring; the base assembly is a fourth support base (231), and the frontal hair main body support is a fourth frontal hair main body support (133).

Images