A gear-constrained variable jaw guard helmet

Abstract

The present invention relates to a gear-constrained variable chin guard helmet. The helmet comprises a stationary gear and a rotating gear, a rotating column capable of telescopic displacement relative to the rotating gear, and a track groove containing a first slope formed on the base and / or the helmet shell. The position and posture of the chin guard are changed during rotation by meshing the rotating gear with a key-type structure formed on the rotating column, in combination with the meshing of the stationary gear and the rotating gear. Furthermore, the constraint of the first slope of the track groove, the action of an energy storage spring, and the telescopic movement of the rotating column enable the fork handle to open and close relative to the symmetrical plane of the helmet shell. Because the fork handle can be retracted when the chin guard is in the full-face helmet configuration, it reduces airflow whistling and reduces the helmet's size, thereby improving the helmet's comfort and storage capabilities. Furthermore, the retracted fork handle can directly transmit the impact force exerted on the chin guard to the helmet shell, thereby improving the stress characteristics and enhancing the helmet's safety and reliability.

Description

Technical Field

[0001] The present invention belongs to the technical field of helmet design, and relates to a helmet including a chin guard structure, and more specifically to a helmet with a variable chin guard structure that can be switched between a full-face helmet position and a half-face helmet position. More specifically, the present invention relates to a helmet with a variable chin guard structure that can achieve structural switching of the chin guard between the full-face helmet position and the half-face helmet position based on gear constraints and can allow the chin guard fork to perform opening and closing displacement movements in a timely manner. Background Art

[0002] As we all know, people need to wear helmets to protect their heads in many situations, such as riding motorcycles and racing cars. Currently, helmets mainly fall into two categories: full-face helmets and half-face helmets. Full-face helmets are equipped with a chin guard that wraps around the user's chin, thus effectively protecting the wearer's entire head. Half-face helmets do not have this chin guard, so the wearer's mouth and nose are exposed, making it easier for them to drink water and talk. There is no doubt that full-face helmets have sufficient safety protection functions, but their user-friendliness is poor. Although half-face helmets are user-friendly, their safety protection functions are poor. Therefore, a helmet with a variable chin guard has emerged, which combines the advantages of a full-face helmet and a half-face helmet. The chin guard of this type of helmet can be switched between a full-face helmet position and a half-face helmet position according to needs. For example, the Spanish patent application ES2329494T3 and the Chinese patent applications CN105901820A, CN109875177A and CN114158814A filed by the applicant of the present patent application, the helmets they involve are helmets with a variable chin guard.

[0003] However, existing variable chin guard helmets generally have a common problem, that is, the two chin guard forks of the chin guard are both arranged in a convex structure relative to the helmet shell body. The reason for this arrangement is that the chin guard must avoid the constraints of the helmet shell body to achieve the change of posture. However, this type of convex layout fork leads to the following shortcomings of the helmet: 1) The convex layout fork will lead to poor aerodynamic performance of the helmet. This is because the chin guard fork protruding from the helmet shell body will inevitably generate turbulence and additional wind resistance during the wearer's riding process. This wind resistance not only causes unnecessary resistance, but also has a negative impact on the wearing reliability of the helmet; 2) The convex layout fork will lead to poor wearing comfort of the helmet. Also due to the turbulence caused by the chin guard fork protruding from the helmet shell body, it will produce an uncomfortable airflow whistling sound when the wearer rides, in other words, it has a negative impact on the wearer's wearing comfort; 3) The convex layout fork will also cause the helmet to increase in size, which is obvious. Due to the relatively larger volume of the helmet, on the one hand, the weight of the helmet becomes heavier and the load burden on the wearer increases, resulting in easy fatigue of the wearer. On the other hand, due to the increased volume of the helmet, its storage space becomes larger, which is obviously not conducive to warehousing, transportation and storage. 4) The convex layout of the fork handle has another defect, which is that it will cause the structural load-bearing capacity of the helmet to become weaker. The reason is that when the helmet is subjected to a strong external collision impact, the impact force generated by the jaw guard cannot be directly transmitted to the helmet shell body through the fork handle body, but is indirectly and dislocatedly transmitted to the helmet shell body through the intermediate connecting piece, resulting in poor impact resistance of the jaw guard, and thus there are certain safety hazards.

[0004] In summary, while existing helmets with variable chin guards can transition between full-face and half-face configurations, their convex grips lead to deficiencies in reliability, comfort, safety, and storage. In short, there's still room for improvement and enhancement in these helmets. Summary of the Invention

[0005] In response to the problems existing in existing helmets with variable chin guard structures, the present invention provides a gear-constrained variable chin guard helmet. The purpose is: while utilizing gear constraints to achieve the conversion of the chin guard position and posture, the chin guard fork handle is improved in the structural form and driving mechanism so that the chin guard fork handle can be in a stowed state in the full helmet position or even the half helmet position, thereby effectively improving the reliability, comfort, safety and storage of the helmet.

[0006] The purpose of the present invention is achieved as follows: a gear-constrained variable jaw guard helmet, which includes a helmet shell body, a jaw guard, two bases and a shield, the helmet shell body has a symmetrical plane, the two bases are separated by the symmetrical plane and are arranged on the two side surfaces of the helmet shell body, and the two bases are fastened to the helmet shell body or the two bases and the helmet shell body are made as an integral structure, the jaw guard has two fork handles, and the two fork handles are arranged on both sides of the helmet shell body; stationary gears and rotating gears are provided on both sides of the helmet shell body, the stationary gear is an internal tooth configuration gear, and the stationary gear is stationary relative to the helmet shell body, and the rotating gear is an external tooth configuration gear, And the rotating gear can change its position relative to the helmet shell body; it is characterized in that: the stationary gear, rotating gear, fork handle and base arranged on the same side of the helmet shell body, together participate in forming a constraint mechanism that can change the position and posture of the jaw guard, wherein the fork handle in the constraint mechanism includes a columnar rotating column, the rotating column has a follower axis that is stationary relative to the fork handle, and a first key-type structure is provided on the rotating column, the axis of the rotating gear is coaxially arranged with the follower axis, and a second key-type structure is also provided on the rotating gear; the stationary gear and the rotating gear belonging to the same constraint mechanism are engaged with each other, and the rotating column and the rotating gear belonging to the same constraint mechanism are connected by the first key The type structure and the second key type structure mesh with each other; a through-shaped groove rail is opened on the base, and the rotating column is in a layout form that passes through the groove rail, and the groove rail includes a track edge and the track edge is in contact with the rotating gear and / or the rotating column. By utilizing the contact behavior, the groove rail can cause the rotating gear to maintain meshing with the stationary gear; when the jaw guard changes its position and posture and moves, the rotating column moves synchronously with the fork handle, and at the same time, the rotating gear meshed with it is driven by the rotating column and also starts to rotate around the follower axis, and the fork handle and the rotating column can also make a telescopic displacement action along the follower axis relative to the rotating gear; in the rotating column A bearing plate is fastened to or integrally formed at the end portion, and an energy storage spring is provided between the bearing plate and the rotating gear on the same side of the helmet shell body; a track groove is provided on the base or the helmet shell body, the track groove including a first sinkhole and a first slope, the bearing plate abuts against the track groove and can slide along the track groove; in response to the chin guard being opened and separated from its full-face helmet structural position, the bearing plate is separated from the first sinkhole and comes into contact with the first slope of the track groove, and this contact enables the bearing plate to overcome the elastic force of the energy storage spring and, via the rotating column, cause the chin guard's fork handle to generate an opening displacement movement away from the symmetrical plane of the helmet shell body;As the chin guard returns to its full-face helmet position, the bearing plate, under the elastic force of the energy storage spring, maintains contact with the first slope and slides along the first slope toward the first recess. Simultaneously, under the pressure of the energy storage spring, the bearing plate, via the rotating column, forces the chin guard's fork to close toward the symmetrical plane of the helmet shell.

[0007] Furthermore, the following axes of the rotating columns disposed on both sides of the helmet shell body are coaxially arranged, and these following axes are arranged perpendicular to the symmetry plane of the helmet shell body.

[0008] Furthermore, a latch is provided on the above-mentioned base or helmet shell body. When the chin guard is in the full helmet structure position and is observed along the follower axis toward the symmetry plane of the helmet shell body, the latch is located farther away from the symmetry plane of the helmet shell body than the force-bearing plate, and when the latch and the force-bearing plate are orthographically projected onto the symmetry plane of the helmet shell body, their projections intersect.

[0009] Furthermore, the energy storage spring is a conical spring.

[0010] Furthermore, the key structures of the rotating gear and the rotating column are both straight-line structures. When the jaw guard changes its position and posture, the rotating gear and the fork have the same rotational angular velocity around the follower axis.

[0011] Furthermore, the above-mentioned track groove includes a second pit and a second slope. In response to the process stage of the chin guard flipping out of its half-helmet structural position, the force-bearing plate appears to be separated from the second pit, and it comes into contact with the second slope of the track groove. At the same time, through this contact behavior, the force-bearing plate can overcome the elastic force of the energy storage spring and prompt the fork handle of the chin guard to produce an opening displacement action away from the symmetrical plane of the helmet shell body through the rotating column; in response to the process stage of the chin guard approaching and seating in its half-helmet structural position, the force-bearing plate maintains contact with the second slope under the elastic force of the energy storage spring and slides toward the second pit along the second slope. At the same time, the force-bearing plate prompts the fork handle of the chin guard to make a closing displacement action close to the symmetrical plane of the helmet shell body through the rotating column under the pressure of the energy storage spring.

[0012] Furthermore, when the chin guard is flipped from the full helmet structure position to the half helmet structure position, the angle through which its fork handle rotates relative to the helmet shell body is 180°.

[0013] Furthermore, the above-mentioned chin guard is provided with a design line for the outer contour line obtained by projecting the fork handle on the symmetry plane of the helmet shell body. The design line falls on the symmetry plane and passes through the fixed point on the chin guard's orthographic projection. The design line L passes through two intersection points. At the same time, an orthogonal line passing through the fixed point and perpendicular to the design line is provided on the symmetry plane, wherein the fixed point is the midpoint of the line connecting the two intersection points of the follower axis of the rotating column on the symmetry plane when the chin guard is in the full helmet structure position and the half helmet structure position. In addition, two boundary lines are provided, which are made by the two intersection points of the follower axis of the rotating column on the symmetry plane when the chin guard is in the full helmet structure position and the half helmet structure position respectively. Both of these boundary lines fall on the symmetry plane and are perpendicular to the design line. Then, the design principle of the outer contour line of the tail of the chin guard fork handle is that the outer contour lines of the orthographic projection of the fork handle between the two boundary lines on the symmetry plane are symmetrically arranged with respect to the design line and the orthogonal line.

[0014] Furthermore, the above-mentioned bearing plate and / or the connecting accessories of the bearing plate are made of magnetically attractive materials or are magnets, and magnets or magnetically attractive parts are provided on the helmet shell body or the base at positions corresponding to the first sinkhole and the second sinkhole.

[0015] The above-mentioned shield includes two supporting sides, which are separated by the symmetrical plane and are located on both sides of the helmet shell body; at least one base includes an outer cover and a bottom cover, and a driving gear that can rotate on a fixed axis, a rack engaged with the driving gear, and a power spring that can drive the driving gear to rotate are equipped on this base or the helmet shell body. The rack is connected to the supporting sides of the shield, and an arc-shaped outer guide groove is provided on the outer cover and / or the helmet shell body, and an arc-shaped inner guide groove is provided on the bottom cover and / or the helmet shell body. The outer guide groove and the inner guide groove together constitute a constraint guide rail and the constraint guide rail is used to constrain the position and posture of the rack.

[0016] Furthermore, the above-mentioned base and / or helmet shell body is provided with a locking tooth mechanism, which includes an external tooth arranged on the rack, an internal tooth mounted on the base or the helmet shell body and a locking tooth spring. The body of the internal tooth is constrained by the base and / or the helmet shell body and under its constraint, the movement of the internal tooth is expressed in the form of linear displacement, or in the form of swinging displacement, or in the form of a composite displacement including linear displacement and swinging displacement, wherein the elastic force of the locking tooth spring always tends to force the internal tooth to press against the external tooth.

[0017] Furthermore, the above-mentioned base and / or the helmet shell body are provided with an unlocking mechanism, which includes a pressing tongue and a retaining spring. The pressing tongue includes an inclined push surface and is arranged between the first sink hole and the second sink hole. When the jaw guard moves from the half-helmet structure position to the full-helmet structure position, the bearing plate can contact the inclined push surface of the pressing tongue and force the pressing tongue to make a giving way action. The giving way action of the pressing tongue can drive the inner locking teeth to disengage from the outer locking teeth to unlock the locking tooth mechanism.

[0018] A shield locking and releasing mechanism is provided at the lower edge of the above-mentioned shield and on the main body of the chin guard, and the shield locking and releasing mechanism includes an inner buckle structure provided at the lower edge of the shield and an outer buckle structure provided on the main body of the chin guard, the inner buckle structure includes a snap structure, and the outer buckle structure includes a probe that can be forced to give way and a lock hook arranged on the probe; in addition, the shield locking and releasing mechanism also includes a first release key and / or a second release key, the first release key and the second release key are both arranged on the main body of the chin guard and they can both serve as actuating parts for releasing the shield, wherein the first release key is provided adjacent to the probe and can touch the probe during the actuation of the first release key, and the second release key can release the chin guard at the full helmet structure position and release the chin guard. The bougie can be controlled during the actuation of the second release button; when the chin guard is in the full-helmet structure position and the shield is fully fastened to the chin guard, the shield locking and releasing mechanism can have three working conditions: a) when the first release button and the second release button are not touched, the lock hook on the bougie is in the original position, and the lock hook in the original position can hook into the buckle structure of the inner buckle structure and thereby lock the shield; b) when the first release button is actuated, the first release button can touch the bougie, and through this touching behavior, the lock hook of the bougie can be caused to leave its original position and thereby release the shield; c) when the second release button is actuated, the second release button can drive the bougie, and through this driving behavior, the lock hook of the bougie can be caused to leave its original position and thereby release the shield.

[0019] The present invention relates to a gear-constrained variable jaw guard helmet, which adopts a configuration of a stationary gear and a rotating gear on a helmet shell body, and a rotating column that can make a telescopic displacement movement relative to the rotating gear is provided on the jaw guard fork handle, and a track groove including a first sink and a first slope is provided on the base support or / and the helmet shell body. On the one hand, the jaw guard is constrained and achieved to achieve a rotational position and posture change by meshing the rotating gear and the key-type structure provided on the rotating column in combination with the gear meshing of the stationary gear and the rotating gear. On the other hand, the jaw guard fork handle is constrained by the first slope of the track groove in combination with the telescopic movement of the rotating column to achieve the displacement movement of the jaw guard fork handle relative to the symmetrical plane of the helmet shell body. In other words, the jaw guard can be lifted up and separated from its full-face helmet structure position, and its fork handle body can be displaced away from the symmetrical plane of the helmet shell body. The jaw guard can be returned to its full-face helmet structure position, and its fork handle body can be displaced close to the symmetrical plane of the helmet shell body. Compared with conventional helmets with variable chin guard structures, the variable chin guard helmet of the present invention can, on the one hand, have its fork extended outward when the chin guard is flipped over to avoid being restrained by the helmet shell and the shield, thereby not affecting its conversion between the full-face helmet structure position and the half-helmet structure position. On the other hand, when the chin guard is in the full-face helmet structure position, its fork can be in a retracted and collapsed structure relative to the helmet shell. This brings the following benefits: first, in the full-face helmet structure, which is commonly worn while driving, the chin guard fork can become an integral part of the helmet shell, eliminating the abrupt protruding fork layout of conventional variable chin guard structures. Therefore, the airflow whistling sound caused by the fork protruding too much from the helmet surface during driving can be effectively eliminated, thereby improving the wearing comfort of the helmet and reducing the size of the helmet, thereby improving its storage capacity. Secondly, the chin guard in a retracted structure when in the full-face helmet structure position can have its fork directly abut against the helmet shell. Therefore, when the chin guard is impacted or collided, the force applied to the chin guard can be directly transmitted to the helmet shell, which will inevitably greatly improve the safety and reliability of the helmet. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is an axonometric view of a gear-constrained variable jaw guard helmet of the present invention, with the jaw guard in a full-face helmet configuration and the shield in a fully buckled-down state;

[0021] Figure 2 yes Figure 1 A side view of the gear-constrained variable jaw guard helmet of the present invention in the state shown;

[0022] Figure 3 yes Figure 1 A front view of the gear-constrained variable jaw guard helmet of the present invention in the illustrated state;

[0023] Figure 4This is an exploded diagram of the assembly of the main parts of a gear-constrained variable jaw guard helmet of the present invention;

[0024] Figure 5 This is a schematic diagram illustrating the layout of a gear-constrained variable jaw guard helmet of the present invention, wherein the stationary gear and the rotating gear comprised therein are meshed with each other;

[0025] Figure 6 This is a schematic diagram of a gear-constrained variable jaw guard helmet according to the present invention, with the rotating gear in different positions;

[0026] Figure 7 This is a side view of a gear-constrained variable chin guard helmet of the present invention, showing the layout of the groove rails on the bottom support when the chin guard is in the full-face helmet structure position;

[0027] Figure 8 yes Figure 7 In the state shown, a cross-sectional view of a gear-constrained variable jaw guard helmet according to the present invention is made along the moving trajectory of the follower axis;

[0028] Figure 9 yes Figure 7 A T-direction view of a gear-constrained variable jaw guard helmet according to the present invention in the illustrated state;

[0029] Figure 10 This is a side view of a gear-constrained variable jaw guard helmet according to the present invention, wherein the jaw guard is positioned above the dome of the helmet shell body;

[0030] Figure 11 yes Figure 10 In the state shown, a cross-sectional view of a gear-constrained variable jaw guard helmet according to the present invention is made along the moving trajectory of the follower axis;

[0031] Figure 12 yes Figure 10 A T-direction view of a gear-constrained variable jaw guard helmet according to the present invention in the illustrated state;

[0032] Figure 13 This is an axonometric view of a gear-constrained variable jaw guard helmet of the present invention, with the jaw guard in a half-helmet configuration and the shield in a fully buckled-down state;

[0033] Figure 14 yes Figure 13 A side view of a gear-constrained variable jaw guard helmet according to the present invention in the state shown;

[0034] Figure 15 yes Figure 13 A front view of the gear-constrained variable jaw guard helmet of the present invention in the illustrated state;

[0035] Figure 16It is a side view of a gear-constrained variable jaw guard helmet of the present invention, with the jaw guard in a half-helmet structure position and the shield in a fully opened state;

[0036] Figure 17 This is a schematic diagram of the state change of the gear-constrained variable jaw guard helmet when its jaw guard is transformed from a full-face helmet structure position to a half-face helmet structure position;

[0037] Figure 18 This is a schematic diagram describing the design of the outer contour line of the rear portion of the chin guard fork 2a of a gear-constrained variable chin guard helmet of the present invention;

[0038] Figure 19 This is a schematic diagram of a gear-constrained variable jaw guard helmet provided with an automatic shield lifting device, a locking mechanism for the shield, and different locking states of the shield;

[0039] Figure 20 This is an exploded assembly diagram of the main components of the shield locking and unlocking mechanism of a gear-constrained variable jaw guard helmet of the present invention;

[0040] Figure 21 The present invention is a schematic diagram describing the state of the shield locking and unlocking mechanism of a gear-constrained variable jaw guard helmet under typical working conditions. DETAILED DESCRIPTION

[0041] The present invention will be further described below with reference to specific embodiments. Figure 1 -twenty one:

[0042] A gear-constrained variable jaw guard helmet, comprising a helmet shell body 1, a jaw guard 2, two bottom supports 3 and a shield 4 (see Figure 4 ), the helmet shell body 1 has a symmetry plane P, the two bottom brackets 3 are separated by the symmetry plane P and are respectively placed on the two sides of the helmet shell body 1, and the two bottom brackets 3 are fastened to the helmet shell body 1 or the two bottom brackets 3 and the helmet shell body 1 are made into an integral structure, Figures 1 to 3 The scene shown is a situation where the base bracket 3 is fastened and installed on the helmet shell body 1 with screws. Here, when the base bracket 3 and the helmet shell body 1 are made of an integrated structure, the base bracket 3 can be regarded as a part of the helmet shell body 1; in addition, the base bracket 3 can be a single integral part or a combined component composed of multiple relatively independent parts. Figure 4 The bottom bracket 3 in the helmet shell includes an outer cover 3a and a bottom cover 3b and is a combined component. The jaw guard 2 of the present invention has two fork handles 2a, and the two fork handles 2a are placed on both sides of the helmet shell body 1 (see Figures 1 to 4A stationary gear 5 and a rotating gear 6 are provided on both sides of the helmet shell body 1. The stationary gear 5 is an internally toothed gear and is stationary relative to the helmet shell body 1. The rotating gear 6 is an externally toothed gear and can change its position and posture relative to the helmet shell body 1. The stationary gear 5 and the rotating gear 6 can be single-size gears (not shown in the figure) each having only one pitch circle, or they can be multi-size gears each having multiple pitch circles. Figure 5 The situation shown is that the stationary gear 5 is a gear having two pitch circles, that is, it has two pitch circle radii. R 1 and R 2 is a composite gear composed of two sections of gear teeth. At the same time, the rotating gear 6 is also a gear containing two pitch circles, that is, it contains two pitch circle radii. r 1 and r 2 is a composite gear composed of two sections of gear teeth. Here, "the rotating gear 6 can change its position and posture relative to the helmet shell body 1" means that the rotating gear 6 can show different positions and different postures relative to the helmet shell body 1 (see Figure 6 ), and the "stationary gear 5 is stationary relative to the helmet shell body 1" includes two situations: one situation is that the stationary gear 5 is a separately manufactured part or component, and then fastened to the helmet shell body 1 and / or the base 3 (not shown in the figure); the other situation is that the stationary gear 5 is made of an integrated structure with the helmet shell body 1 and / or the base 3. Figure 4 The example shown is a case where the stationary gear 5 and the base 3 (more specifically, the stationary gear 5 and the outer cover 3a of the base 3) are manufactured as an integral structure. In this case, the stationary gear 5 can be considered a part of the base 3. Of course, the stationary gear 5 can also be manufactured as an integral structure with the bottom cover 3b of the base 3 (not shown in the figure). It should be noted that the function of the shield 4 in the present invention is to prevent wind, sand and rain from invading the interior of the helmet to avoid negatively affecting the driving experience of the helmet wearer. The main structure of the shield 4 is made of a transparent material that does not hinder the helmet wearer's observation. In addition, the position of the shield 4 can be selected according to the user's needs. It can be manually buckled and opened. Figures 1 to 3 The situation shown is when the chin guard 2 is in the full helmet configuration and the shield 4 is in a fully engaged state. At this time, the shield 4 can provide the best protection against wind, sand and rain. Here, the phrase "the two forks 2a are located on both sides of the helmet shell body 1" in the present invention means that the two forks 2a are separated by the symmetry plane P of the helmet shell body 1 and are located on both sides of the helmet shell body 1 (see Figure 3 ), where the symmetry plane P refers to such a plane (see Figures 1 to 4 、 Figure 8 and Figure 9 、 Figures 11 to 13 、 Figure 15 ): When the wearer wears the helmet normally, the symmetry plane P passes through the wearer's mouth, nose and top of the skull and separates the wearer's eyes and ears on both sides of it. That is, the symmetry plane P is an imaginary plane with the property of dividing the helmet shell body 1 in the middle. Arranging on the same side of the helmet shell body 1 means arranging on the same side of the symmetry plane P. At the same time, there is an intersection line S between the symmetry plane P and the outermost surface of the helmet and the outermost surfaces of some parts and accessories (such as Figure 1 、 Figure 3 and Figure 4 、 Figure 9 、 Figure 12 and Figure 13 、 Figure 15 As shown); In addition, the helmet shell body 1 mentioned in the present invention is a general term, which includes the main body of the helmet shell cover and other various parts and accessories fastened or attached to the shell cover body, such as windshields, covers, hangers, seals, fasteners, buffering and energy-absorbing parts, and other functional parts or decorative parts. It is worth noting that the best layout of the base 3 in the present invention is to be arranged on the side of the helmet shell body 1 close to or near the ears of the helmet wearer (such as Figures 1 to 3 、 Figure 5 、 Figure 7 、 Figure 9 and Figure 10 、 Figures 12 to 16 As shown in the figure, the preferred layout of the jaw guard 2 is that its two forks 2a are located on either side of the symmetry plane P of the helmet shell 1 and correspond to the position of the base 3. The present invention is characterized in that the stationary gear 5, rotating gear 6, forks 2a, and base 3, located on the same side of the helmet shell 1, together constitute a restraining mechanism capable of changing the position and posture of the jaw guard 2. The forks 2a in the restraining mechanism include a cylindrical rotating column 7 (see FIG. 1 ). Figure 4 ), the rotating column 7 has a follower axis O1 that is stationary relative to the fork handle 2a, and a key-type structure 67 is provided on the rotating column 7 (such as Figure 4 and Figure 21 As shown in FIG. 1 ), the axis of the rotating gear 6 is coaxial with the follower axis O1, and a key structure 67 is also provided on the rotating gear 6 (as shown in FIG. Figure 4 As shown in FIG), the rotating column 7 of the present invention can be an independent part (not shown in the figure) that is fastened to the fork handle 2a. In addition, the rotating column 7 can also be made into an integral structure with the fork handle 2a (see FIG). Figure 4), in addition, the "axis of the rotating gear 6" refers to the axis passing through the center of the gear pitch circle and perpendicular to the plane where the pitch circle is located; here, the key-type structure 67 refers to various geometric structures with protrusions and depressions, especially including convex keys or keyways with a certain axial length. The cross-sectional shape or cross-sectional profile of the key-type structure 67 can be various forms such as rectangular, tooth-shaped, cycloid or a combined profile composed of various other curves. The number of key-type structures 67 can be one or two or more. Typical key-type structures 67 are convex splines and concave keyways, etc. Figure 4 and Figure 21 In the illustrated case, the key structure 67 of the rotating column 7 and the rotating gear 6 is a spline-shaped multi-key form. It should be noted that the key structure 67 can be an independent part and then fastened to the corresponding rotating gear 6 or rotating column 7 (not shown in the figure). In addition, the key structure 67 can also be made in an integral structure with the rotating gear 6 or the rotating column 7 (as shown in the figure). Figure 4 It should be emphasized that the key structure 67 can not only be a continuous structure such as a long strip of convex key or keyway (see Figure 4 ), and the key-type structure 67 can also be a discontinuous structure such as a single boss or bead, and a plurality of discontinuously arranged bosses or bead (not shown in the figure), but no matter what kind of structure it is, as long as the rotating gear 6 and the rotating column 7 can complete the circumferential transmission of power and motion between the two when they cooperate with each other, and can also complete the axial relative telescopic action between the two, it can be regarded as belonging to the category of the key-type structure 67 described in the present invention; it is particularly important to point out that the constraining mechanism in the present invention can have other components in addition to the aforementioned stationary gear 5, rotating gear 6, fork handle 2a and base 3. For example, when the helmet shell body 1 plays a constraining role in the structural transformation of the jaw guard 2, the helmet shell body 1 can also be regarded as participating in the construction of the constraining mechanism. That is to say, as long as the parts and components make a constraint contribution to the change of the position and posture of the jaw guard 2, they can be regarded as jointly participating in the formation of a constraint mechanism that can change the position and posture of the jaw guard 2; in the present invention, the stationary gear 5 and the rotating gear 6 belonging to the same constraint mechanism are meshed with each other, and the rotating column 7 and the rotating gear 6 belonging to the same constraint mechanism are meshed with each other through their key-type structures 67 (also called bite fit). The main feature of these meshing fits is that they can transmit motion and power to each other, especially including the linkage response of position and posture; it should be noted that when the stationary gear 5 and the rotating gear 6 are both composite gears composed of two sections of gear teeth with two pitch circles, their respective gear tooth segments correspond to each other to form a meshing pair, such as Figure 5 The stationary gear 5 shown includes two pitch circle radii R 1 andR 2. The rotating gear 6 that meshes with it also has two pitch circle radii. r 1 and r 2, so it corresponds to the pitch circle radius R 1 Corresponding stationary gear 5 tooth segment and corresponding pitch circle radius r 1 The corresponding rotating gear 6 gear segments form a meshing pair, and the corresponding pitch circle radius R 2 Corresponding stationary gear 5 tooth segments and corresponding pitch circle radius r 2 The corresponding rotating gear 6 gear segments form a meshing pair (such as Figure 6 As shown); It should also be noted that the key-type structures 67 of the rotating column 7 and the rotating gear 6 described in the present invention, which cooperate with each other, are in a "male-female" matching form, that is, if the main structure of the key-type structure 67 of the rotating column 7 is a protruding convex key, then the main structure of the key-type structure 67 of the rotating gear 6 that meshes with it must be a concave keyway, and vice versa; a through-shaped groove rail 8 is provided on the base bracket 3, and the groove rail 8 can be provided on the outer cover 3a of the base bracket 3 (as shown in FIG. Figure 4 As shown in the figure) it can also be opened on the bottom cover 3b (not shown in the figure), and the rotating column 7 is in a layout form that passes through the groove track 8; the groove track 8 includes at least one track edge 8a, and the track edge 8a is in contact with the rotating gear 6 and / or the rotating column 7. By utilizing this contact behavior, the groove track 8 can cause the rotating gear 6 to maintain engagement with the stationary gear 5, wherein the "track edge 8a is in contact with the rotating gear 6 and / or the rotating column 7" includes three situations: the first situation is that the track edge 8a is in contact with the rotating gear 6 but not with the rotating column 7 (such as Figure 8 As shown, in Figure 8 The track edge 8a is in contact with the hub flange 6a of the rotating gear 6), the second situation is that the track edge 8a is in contact with the rotating column 7 but it is not in contact with the rotating gear 6 (not shown in the figure), and the third situation is that the track edge 8a is in contact with both the rotating gear 6 and the rotating column 7 (not shown in the figure); when the jaw guard 2 changes position and posture and moves (that is, when the jaw guard 2 switches between the full helmet structure and the half helmet structure), the rotating column 7 will follow the fork handle 2a to make synchronous movement, and the follower axis O1 will also follow and move synchronously. Figure 6 As shown, Figure 5 and Figure 7 The situation shown reflects the movement trajectory of the follower axis O1 n The rotating gear 6 is driven by the rotating column 7 to start rotating around the follower axis O1 (see Figure 6 ), and the fork handle 2a and the rotating column 7 can also make a telescopic displacement action along the axial direction of the follower axis O1 relative to the rotating gear 6. Figures 7 to 9 and Figures 10 to 12 The effect of the telescopic displacement can be clearly seen in the two states shown, where Figure 8 It is along Figure 7 The moving trajectory of the follower axis O1 is shown n The AA section view made, Figure 9 It is along Figure 7 The view from the T direction of the helmet in the state shown (this view is the rear view of the helmet), Figure 11 It is along Figure 10 The moving trajectory of the follower axis O1 is shown n The AA section view made, Figure 12 It is along Figure 7 The view obtained from the T direction of the helmet in the shown state (the T direction view is the rear view of the helmet); Figure 6 In the described situation: along with the rotation of the rotating gear 6, on the one hand, the position of the follower axis O1 also synchronously presents different positions relative to the base 3 (equivalently relative to the helmet shell body 1). On the other hand, since the rotating gear 6 has a transmission relationship with the rotating column 7 through the key structure 67 and further has a motion relationship associated with the fork handle 2a, Figure 6 (a) The position and posture of the rotating gear 6 reflected in the figure correspond to the jaw guard 2 and its fork handle 2a being in the full helmet structure position. Figure 6 (c) The position and posture of the rotating gear 6 reflected in the figure correspond to the jaw guard 2 and its fork handle 2a being in the half helmet structure position. Figure 6 (b) The position and posture of the rotating gear 6 reflected in the figure correspond to the position of the chin guard 2 and its fork handle 2a being between the full helmet structure position and the half helmet structure position; here, since the rotating column 7 is fastened to or integrally made on the fork handle 2a, it is obvious that they move synchronously together. In addition, since the rotating column 7 and the rotating gear 6 are engaged through the key structure 67, there is a coupled related movement between the two, and from Figure 6It is not difficult to see that the rotating gear 6 not only changes its position but also its angle. In other words, under the constraints of the stationary gear 5 and the rotating gear 6, the position and posture of the chin guard 2 of the present invention can be changed in a controllable manner. It is particularly important to point out that the rotating gear 6 of the present invention is a component that can make relative displacement movement along the follower axis O1 relative to the fork handle 2a (including the rotating column 7). This is crucial and necessary for realizing the displacement movement of the fork handle 2a away from and towards the symmetry plane P of the helmet shell body 1. The main contribution of the present invention is that when the chin guard 2 needs to be converted between the full helmet structure position and the half helmet structure position, it can realize that the fork handle 2a has a retracted structural layout in the full structure position (see Figures 7 to 9 ) in order to improve the aerodynamic characteristics, structural strength and rigidity characteristics, storage and transportation adaptability of the helmet, and to enable the fork handle 2a to be transformed from a retracted state to an open state during the transformation of the jaw guard 2 structural state (see Figures 10 to 12 ) to avoid the hindrance of the helmet shell body 1 and the shield 4 without hindering the position and posture change of the jaw guard 2, which is precisely the most obvious difference between the technical solution of the present invention and the technical solution proposed in Chinese patent application CN105901820A. It should be pointed out that when the key structure 67 included in the rotating gear 6 and the rotating column 7 is a straight-line structure (that is, the generatrix of the key structure 67 is parallel to the follower axis O1, as shown in FIG. Figure 4 As shown in the figure), the displacement movement of the rotating gear 6 relative to the fork handle 2a can only be carried out in the axial direction of the follower axis O1, but at this time the rotating gear 6, the fork handle 2a and the rotating column 7 all have the same rotational movement around the follower axis O1 (or they have the same angular velocity around the follower axis O1). When the key structure 67 contained in the rotating gear 6 and the rotating column 7 is a non-straight-grained structure, such as a diagonal structure, that is, the generatrix of the key structure 67 is not parallel to the follower axis O1 (not shown in the figure), then at this time the displacement movement of the rotating gear 6 relative to the fork handle 2a is a composite movement that is carried out simultaneously in the axial direction of the follower axis O1 and in the rotational direction around the follower axis O1. From the perspective of facilitating manufacturing, the optimal structural form of the key structure 67 of the rotating gear 6 and the rotating column 7 is a straight-grained structure (such as Figure 4 As shown); The present invention has a bearing plate 9 fastened to the end of the rotating column 7 or made into an integral structure, and an energy storage spring 10 is provided between the bearing plate 9 and the rotating gear 6 on the same side of the helmet shell body 1 (see Figure 4 And as Figure 8 and Figure 11As shown), one end of the energy storage spring 10 rests on the bearing plate 9 and the other end rests on the body of the rotating gear 6 (so it is not difficult to find that the energy storage spring 10 can move along with the rotating gear 6 and the bearing plate 9). At the same time, a track groove 11 is provided on the base 3 and / or the helmet shell body 1. The track groove 11 includes a first sinkhole 11a and a first slope 11b. The layout feature of the first sinkhole 11a is that it is closer to the symmetry plane P of the helmet shell body 1 than the main track surface 11c of the track groove 11, and the first slope 11b is a connecting structure between the main track surface 11c and the first sinkhole 11a (see Figure 4 、 Figure 8 and Figure 11 ), the bearing plate 9 abuts against the track groove 11 and can slide along the track groove 11. The characteristic of this sliding motion is that on the one hand, it moves along the follower axis O1, and on the other hand, it also has a rotational motion around the follower axis O1. It is worth emphasizing that the bearing plate 9 in the present invention can be a structure on the rotating column 7, such as a column head or a flange or an annular groove (not shown in the figure). In particular, the bearing plate 9 can be a separate part that is fastened to the rotating column 7 (see Figure 4 、 Figure 8 and Figure 11 ), and making the bearing plate 9 into a disc-shaped part is more conducive to increasing its contact surface with the track groove 11, thereby improving the stability of the jaw guard 2 when changing position and posture, and at the same time facilitating the assembly of the energy storage spring 10 and receiving the elastic force of the energy storage spring 10; it should be noted that the purpose of setting the energy storage spring 10 in the present invention is: on the one hand, it is used to generate a force that can prompt the fork handle 2a to approach the symmetry plane P of the helmet shell body 1, and on the other hand, it is used to utilize the squeezing effect generated by its elastic force to effectively eliminate the gap between the relevant components of the jaw guard 2 when changing position and posture to facilitate improving the stability of the movement. In order to achieve these purposes, the energy storage spring 10 is generally preferably pre-compressed or pre-stretched before being installed on the helmet, and the structural form of the energy storage spring 10 can be of various types. In particular, the energy storage spring 10 can be a conical spring (such as Figure 4 、 Figure 8 and Figure 11As shown, conical springs are one of the preferred structural layouts for the energy storage spring 10 because they can achieve a smaller axial dimension when compressed, thereby facilitating a reduction in helmet size. As the chin guard 2 is lifted and released from its full-face helmet configuration, the bearing plate 9 disengages from the first recess 11a and comes into contact with the first slope 11b of the track groove 11. This contact allows the bearing plate 9 to overcome the elastic force of the energy storage spring 10 and ultimately, via the rotating column 7, cause the fork 2a of the chin guard 2 to open and displace away from the symmetry plane P of the helmet shell 1. This opening and displacement occurs because the bearing plate 9's contact with the first slope 11b during the chin guard 2's lift and release phase is a climbing motion. At this point, the bearing plate 9 is stretched open by the first slope 11b, displacing it away from the symmetry plane P of the helmet shell 1. As the chin guard 2 returns to its full-face helmet configuration, the bearing plate 9, under the force of the energy storage spring 10, maintains contact with the first slope 11b and slides along this slope toward the first recess 11a. Simultaneously, under the pressure of the energy storage spring 10, the bearing plate 9, via the rotating column 7, causes the prongs 2a of the chin guard 2 to undergo a closing displacement movement toward the symmetry plane P of the helmet shell 1. The aforementioned "the prongs 2a undergo an opening displacement movement away from the symmetry plane P of the helmet shell 1" and "the prongs 2a undergo a closing displacement movement toward the symmetry plane P of the helmet shell 1" can be collectively referred to as "opening and closing displacement movements." This reflects the fact that the prongs 2a, located on either side of the helmet shell 1, exhibit both opening and closing movements relative to the symmetry plane P of the helmet shell 1, a key feature that distinguishes the present invention's helmet from existing variable chin guard helmets. In addition, the above-mentioned "responding to the process stage of the chin guard 2 being opened and separated from its full-helmet structural position" refers to: the chin guard 2 is opened from the full-helmet structural position until the fork handle 2a of the chin guard 2 completes the opening displacement required to avoid and cross the outer surface of the helmet shell body 1 and the entire shield 4 and move towards the half-helmet structural position. The "responding to the process stage of the chin guard 2 returning to its full-helmet structural position" refers to: when the chin guard 2 is seated in the full-helmet structural position, its fork handle 2a starts to move from the maximum opening state relative to the helmet shell body 1, and moves closer to the symmetry plane P of the helmet shell body 1 until the chin guard 2 is completely in place in the full-helmet structural position. The full-helmet structural position refers to the period when the chin guard 2 of the helmet is completely buckled and can embrace the wearer's chin and mouth, and therefore has the best safety protection effect (such as Figures 1 to 3 The half helmet structure position refers to the position in which the chin guard 2 of the helmet is opened without blocking the eyes, nose and mouth of the helmet wearer, and in particular includes the position in which the chin guard 2 is buckled down and abuts against the upper rear surface of the helmet shell body 1 after climbing over the shield 4 (as shown in FIG. Figures 13 to 16 As shown in the figure, the chin guard 2 in the half-helmet structure does not hinder the wearer from drinking water, talking, making phone calls, and breathing, so it is very suitable for the wearer to wear when taking a break or driving at low speed. It should be noted that even if the chin guard 2 is in the half-helmet structure, the shield 4 can be completely buckled down (as shown in the figure). Figures 13 to 15 as shown) and fully opened (as shown) Figure 16 Obviously, the present invention configures a stationary gear 5 and a rotating gear 6, and provides a rotating column 7 that can make a telescopic displacement action relative to the rotating gear 6, and provides a track groove 11 including a first slope 11b on the bottom bracket 3 and / or the helmet shell body 1. On the one hand, the position and posture of the jaw guard 2 during rotation are changed by utilizing the meshing of the rotating gear 6 and the key-type structure 67 provided on the rotating column 7 in combination with the meshing of the gears of the stationary gear 5 and the rotating gear 6, thereby realizing the structural variability of the jaw guard 2. On the other hand, the constraint of the first slope 11b in the track groove 11 on the bearing plate 9 and the telescopic movement of the rotating column 7 generated by the action of the energy storage spring 10 are utilized to achieve the opening and closing displacement action of the fork handle 2a relative to the symmetry plane P of the helmet shell body 1, thereby facilitating the improvement of the ability of the jaw guard 2 to climb over various obstacles such as the helmet shell body 1 and the shield 4. The following is combined with Figure 17 The following describes the state changes of the jaw guard 2 during its switching position and posture: Figure 17 (a) reflects that the chin guard 2 is in the full helmet structure position, at this time, its fork handle 2a is in the state of being stored and abutting against the helmet shell body 1, that is, at this time, the fork handle 2a is in the closest retracted state relative to the symmetry plane P of the helmet shell body 1, and corresponds to the position of the bearing plate 9 being completely seated in the first sinkhole 11a (as shown in FIG. Figure 8 shown); Figure 17 (b) reflects the initial stage when the helmet wearer opens the chin guard 2 with his hands. At this time, the shield 4 is lifted and opened to the vicinity of the dome of the helmet shell body 1, and the bearing plate 9 begins to climb along the first slope 11b of the track groove 11. Along with this climbing behavior, the fork handle 2a gradually moves away from the symmetry plane P of the helmet shell body 1. Specifically, the amplitude value of the fork handle 2a opened during this period compared with its position in the full helmet structure state is δ is also gradually increasing, and in this process, along with the amplitude value δ The greater the value of the energy storage spring 10, the greater the degree to which it deviates from its equilibrium state (ie, free state). In other words, the elastic force of the energy storage spring 10 will also increase. Figure 17 (c) reflects the situation that the jaw guard 2 begins to climb over the fully opened shield 4. At this time, the bearing plate 9 has climbed the first slope 11b and is in contact with the main track surface 11c of the track groove 11 (as shown in FIG. Figure 11In other words, during this period, the fork handle 2a has completed the full range of opening action, that is, it is at the position farthest from the symmetry plane P of the helmet shell body 1, or in other words, during this period, the fork handle 2a is opened by a value greater than that in the full helmet structure state. δ reached its maximum value (see Figure 11 and Figure 12 ), and at this maximum opening amplitude δ The present invention can ensure that the fork handle 2a can cross (or avoid) various obstacles on the outer surface of the helmet shell body 1, especially the shield 4. Of course, the elastic force of the energy storage spring 10 is at its strongest state at this time. Figure 17 (d) reflects that the jaw guard 2 has crossed the fully opened shield 4 and is crossing the dome of the helmet shell body 1. Correspondingly, at this time, the bearing plate 9 continues to maintain contact with the main track surface 11c of the track groove 11, and the fork handle 2a continues to maintain the maximum open state (i.e., the amplitude value δ Still maintain the maximum value state); Figure 17 (e) reflects that the chin guard 2 has reached and is in the full helmet structure position and the shield 4 is still in the fully opened state; Figure 17 (f) reflects the state where the chin guard 2 is in the full-face helmet configuration and the hood 4 is in the fully engaged position. This is, of course, accomplished manually by the wearer. It should be noted that the reverse process described above is the conversion of the chin guard 2 from the half-face helmet configuration back to the full-face helmet configuration. The basic principles underlying the opening and closing movement of the fork handle 2a during this process are similar and will not be elaborated upon here. In summary, because the fork handle 2a of the chin guard 2 can be retracted when in the full-face helmet configuration, the technical solution of the present invention can reduce airflow whistling and reduce the size of the helmet, thereby improving the comfort and storage of the helmet. Furthermore, the retracted fork handle 2a can directly transmit the impact force exerted on the chin guard 2 to the helmet shell 1. Therefore, the technical solution of the present invention can also improve the force characteristics, thereby enhancing the safety and reliability of the helmet.

[0043] Furthermore, the layout of the following axis O1 in the present invention can be in various forms, including the following axis O1 being perpendicular or oblique to the symmetry plane P of the helmet shell body 1. In particular, the following axes O1 of the rotating columns 7 disposed on both sides of the helmet shell body 1 are coaxially arranged (i.e., they are collinear), and the coaxial following axes O1 are arranged perpendicular to the symmetry plane P of the helmet shell body 1 (see Figure 4 And as Figure 3 、 Figure 8 、 Figure 9 、 Figure 11 and Figure 15As shown), the advantage of such an arrangement is that when the jaw guard 2 changes its position and posture, the motion interference caused by the inconsistent pace of the forks 2a on both sides of the helmet shell body 1 can be avoided as much as possible, and in particular, the forks 2a on both sides of the helmet shell body 1 can be guaranteed to have the best motion coordination and consistency. Furthermore, the base 3 and / or the helmet shell body 1 of the present invention can be provided with a latch 12 (such as Figure 4 、 Figure 8 and Figure 11 As shown in FIG, the layout principle of the latch tongue 12 is that when the chin guard 2 is in the full helmet structure position and is observed along the direction of the follower axis O1 toward the symmetry plane P of the helmet shell body 1, the latch tongue 12 is located farther from the symmetry plane P of the helmet shell body 1 than the bearing plate 9 (see FIG. Figure 8 ), and when the tongue 12 and the bearing plate 9 are projected onto the symmetry plane P of the helmet shell body 1, the projections of the two intersect, which means that the layout position of the tongue 12 should correspond to the position of the first sinkhole 11a (see Figure 4 、 Figure 8 and Figure 11 The purpose of providing the latch tongue 12 is to prevent the fork handle 2a from uncontrolled opening due to accidental impact or unintentional operation when the chin guard 2 is in the full-face helmet structure position. Because when the chin guard 2 is in the full-face helmet structure position, if it is accidentally impacted or the fork handle 2a has an unexpected outward expansion tendency due to improper human operation, the bearing plate 9 will hit the latch tongue 12 and be restricted by the latch tongue 12. Then the bearing plate 9 will limit the further outward expansion of the fork handle 2a through the pulling of the rotating column 7. This is beneficial to improving the firmness of the chin guard 2 for a full-face helmet structure. Therefore, providing the latch tongue 12 can improve the reliability and safety of the helmet.

[0044] In order to make the jaw guard 2 in the half helmet structure position, the fork handle 2a of the jaw guard 2 can also have a storage effect of being attached to the helmet shell body 1 (see Figure 15 ), so that the helmet can achieve good aerodynamic performance even in the half-helmet structural position, a second sinkhole 11d and a second slope 11e (such as Figure 4 、 Figure 8 and Figure 11 As shown in FIG. 1 ), in response to the jaw guard 2 flipping out of its half-helmet structure position, the bearing plate 9 appears to be out of the second sinkhole 11d, and it comes into contact with the second slope 11e of the track groove 11. At this time, the bearing plate 9 is climbing along the second slope 11e. During this period, the amplitude of the fork handle 2a opened compared to its position in the half-helmet structure state is δ is also gradually increasing, and is accompanied by the amplitude value δThe energy storage spring 10 deviates from its equilibrium state more and more as its value increases. In other words, the elastic force of the energy storage spring 10 will also increase. At the same time, the contact between the bearing plate 9 and the second slope 11e enables the bearing plate 9 to overcome the elastic force of the energy storage spring 10 and promote the fork handle 2a of the jaw guard 2 to produce an opening displacement action away from the symmetry plane P of the helmet shell body 1 through the rotating column 7 (not shown in the figure). The layout feature of the second sinkhole 11d described here is that it is closer to the symmetry plane P of the helmet shell body 1 than the main track surface 11c of the track groove 11, and the second slope 11e is the connecting structure between the main track surface 11c and the second sinkhole 11d (as shown in the figure). Figure 4 、 Figure 8 and Figure 11 As shown); Similarly, in response to the process of the jaw guard 2 approaching and seating on its half-helmet structure, the bearing plate 9 maintains contact with the second slope 11e under the elastic force of the energy storage spring 10 and slides along the second slope 11e to the second sinkhole 11d (at this time, the bearing plate 9 is descending along the second slope 11e). At the same time, the bearing plate 9, under the pressure of the energy storage spring 10, causes the fork handle 2a of the jaw guard 2 to make a closing displacement action close to the symmetrical plane of the helmet shell body 1 through the rotating column 7. During this process, the amplitude of the opening of the fork handle 2a is δ The fork handle 2a is also gradually decreasing, that is, the fork handle 2a will be closer to the helmet shell body 1 (not shown in the figure). Obviously, when the chin guard 2 reaches the half helmet structure position, its fork handle 2a will show a good shrinking effect, so that the helmet can have better aerodynamic performance (see Figure 15 It should be noted that when the symmetry plane P of the helmet shell body 1 is used as the observation reference, the slope direction of the second slope 11e is opposite to the slope direction of the first slope 11b mentioned above. Figure 4 、 Figure 8 and Figure 11 It is not difficult to see from the above. It should also be pointed out that in order to ensure that the chin guard 2 has good stability when it is in the half helmet structure position and to prevent the fork handle 2a from accidentally expanding due to accidental impact or improper human operation, the present invention can also provide a latching tongue 12 (such as Figure 4 、 Figure 8 and Figure 11 The layout principle is as mentioned above and will not be repeated here.

[0045] In order to obtain a better appearance design and improve wearing comfort, the present invention can design the variable flip angle of the chin guard 2 to be 180 degrees, that is, when the chin guard 2 is flipped from the full helmet structure position to the half helmet structure position, the angle of its fork handle 2a relative to the helmet shell body 1 is 180 degrees. Conversely, when the chin guard 2 returns from its half helmet structure position to its full helmet structure position, its fork handle 2a also rotates 180 degrees relative to the helmet shell body 1. Under this layout design, when the chin guard 2 of the helmet is in the half helmet structure position, the center of gravity of the chin guard 2 can be well located above or close to the wearer's neck. Therefore, even if the helmet is transformed into a half helmet, it still has a better force layout (see Figures 13 to 16 ), thereby relieving the driver's fatigue. In other words, this design concept of the chin guard 2 fork 2a can indirectly improve the safety of the helmet. Furthermore, in order to better coordinate the layout design of the fork 2a in the full helmet structure position and the half helmet structure position so as to meet the needs of the helmet appearance, and in particular to ensure that the chin guard 2 can better adhere to the helmet shell 1 in both positions and have a better aerodynamic shape, the present invention is directed to the outer contour line of the tail of the fork 2a of the chin guard 2 m The following design principles are proposed for the layout: Figure 18 , a contour line is provided for the fork handle 2a obtained by orthographic projection on the symmetry plane P of the helmet shell body 1 m Design line L , the design line L The design line can be selected by the designer according to the overall appearance of the helmet. L It can be a free straight line or a limited baseline, but it must meet the design line L The layout principle is that it falls on the symmetry plane P and passes through the fixed point P0 on the positive projection of the jaw guard 2. At the same time, a line passing through the fixed point P0 and aligning with the design line is set on the symmetry plane P. L Orthogonal lines that intersect perpendicularly T , wherein the fixed point P0 is the midpoint of the line connecting the two intersection points of the following axis O1 of the rotating column 7 on the symmetry plane P when the jaw guard 2 is in the full helmet structure position and the half helmet structure position, that is, the intersection point O11 of the following axis O1 and the symmetry plane P in the full helmet structure position and the intersection point O12 of the following axis O1 and the symmetry plane P in the half helmet structure position. The midpoint of the line connecting the two is the fixed point P0. In addition, two boundary lines are provided, which are made by the two intersection points O11 and O12 of the following axis O1 of the rotating column 7 on the symmetry plane P when the jaw guard 2 is in the full helmet structure position and the half helmet structure position respectively. T 1. These two boundaries T 1 fall on the symmetry plane P and they are all aligned with the design line L Perpendicular (in other words, equivalent to a perpendicular line) Tparallel), then the orthographic projection of the fork handle 2a on the symmetry plane P falls on these two boundaries. T 1 The outer contour line within the range m Expressed as about design line L and orthogonal lines T Since the optimal layout of the following axis O1 is perpendicular to the symmetry plane P, in this case, for the convenience of description, the present invention can mark the intersection O11 of the following axis O1 and the symmetry plane P when the chin guard 2 is in the full helmet structure position as O1 (O11), as shown in FIG. Figures 5 to 7 and Figure 18 As shown, when the jaw guard 2 is in the half helmet structural position, the intersection O12 of the follower axis O1 and the symmetry plane P can also be marked with O1 (O12). Figure 6 It should be noted that the outer contour line of the tail body of the fork handle 2a that can meet the above design principles m There are many schemes, two of which are elliptical (including various non-strict elliptical curve-like elliptical shapes) and rhombus (including various non-strict four-straight line rhombus-like rhombuses), including the outer contour line m It is a part of the ellipse and rhombus, or the outer contour line mentioned in the present invention. m It can be composed of several line segments without having to limit it to a complete ellipse or rhombus. Figure 18 In the case shown, there are four outer contour lines. m The main body of the so-called "rhombus-like" is formed. At this time, it can also be said that the outer contour line of the tail of the fork handle 2a m It is designed in a rhombus shape and Figure 18 Design lines described in L Designed to pass through the intersection O11 and the intersection O12; As mentioned above, in addition to this layout design, the tail outer contour line of the fork handle 2a m Other configurations can also be used, and the design line L It is also possible to choose not to pass through the intersection O11 and / or the intersection O12. The present invention adopts the outer contour line of the tail of the fork handle 2a mThe layout design principle has the following benefits: better storage and retraction effect can be achieved, because sufficient recesses must be reserved on the helmet shell body 1 to avoid the fork handle 2a of the chin guard 2, so that the fork handle 2a can be retracted into the main body of the helmet shell body 1 when in the full helmet structure position and the half helmet structure position. When the chin guard 2 is flipped from the full helmet structure position to the half helmet structure position and its fork handle 2a is rotated 180° relative to the helmet shell body 1, the above design can allow the recess to meet the sealing requirements of the fork handle 2a when responding to the full helmet structure and the half helmet structure. At this time, no matter it is in the full helmet structure position or the half helmet structure position, the fork handle 2a can be perfectly or with a small gap or even without a gap against the helmet shell body 1, which is not only beneficial to the appearance of the helmet, but also helps to improve the aerodynamic performance of the helmet.

[0046] To further enhance the reliability of the fork handle 2a when folded, the present invention can design the bearing plate 9 and / or its connecting accessories to be made of a magnetically attractive material or a magnet. Furthermore, magnets or magnetically attractive components (not shown) are provided on the helmet shell body 1 or the base 3 at locations corresponding to the first and second recesses 11a and 11d. The connecting accessories of the bearing plate 9 include various parts connected to the bearing plate 9, as well as fasteners such as screws and washers that connect the bearing plate 9 to the fork handle 2a. The advantage of providing magnets and using magnetically attractive materials is that the driving force of the energy storage spring 10 can be compensated. This is because the characteristic of magnetic attraction is that the closer the two acting magnets are to each other, the stronger the magnetic force generated is. The characteristic of the spring is that the smaller the spring body deviates from its free state (also called free length), the weaker the force generated is, and vice versa. Therefore, as long as the mechanical properties of both are fully utilized to arrange them to generate the opening and closing displacement action of the fork handle 2a, for example, if a magnetic acting body dominated by the attractive force is arranged at the extended end of a spring dominated by the compression force, the gradually increasing magnetic attraction can be used to compensate for the gradually weakening spring force. This can be beneficial to improving the stability and reliability of the jaw guard 2.

[0047] The shield 4 of the present invention comprises two supporting side edges 4a (see Figure 4 ), the two supporting side edges 4a are separated by a symmetry plane P and are placed on both sides of the helmet shell body 1; at least one bottom bracket 3 includes an outer cover 3a and a bottom cover 3b, and a driving gear 13 that can rotate around a fixed axis, a rack 14 that meshes with the driving gear 13, and a power spring 15 (such as a spring 15) that can drive the driving gear 13 to rotate are installed on the bottom bracket 3 or the helmet shell body 1. Figure 4 and Figure 19As shown), the rack 14 is connected to the supporting side 4a of the shield 4, an arc-shaped outer guide groove 16a is provided on the outer cover 3a and / or the helmet shell body 1, and an arc-shaped inner guide groove 16b is provided on the bottom cover 3b and / or the helmet shell body 1. The outer guide groove 16a and the inner guide groove 16b together constitute a pair of constraint guide rails and use the constraint guide rails to constrain the position and posture of the rack 14, thereby achieving the purpose of controlling the position and posture of the shield 4 through the rack 14; Figure 4 In the embodiment, an outer guide groove 16a is provided on the outer cover 3a of the base 3, and at least a part of the main structure of the outer guide groove 16a is in the shape of a through groove, and an inner guide groove 16b is provided on the bottom cover 3b of the base 3. The rack 14 can slide in the constraint guide rail formed by the outer guide groove 16a and the inner guide groove 16b, and is fastened to the supporting side 4a of the shield 4 by a pin (or screw) provided on the rack 14 and passing through the through groove on the guide groove 16a and in combination with the retaining block 4d. In particular, the present invention also includes a situation in which the inner guide groove 16b and the outer guide groove 16a and the constraint guide rail formed by them are all in the form of arc-shaped structural constraints. In other words, due to their constraints, the movement of opening or closing the shield 4 will be in the form of fixed-axis rotation or fixed-axis swing. Moreover, compared with the traditional rocker constraint form, the constraint structure of the shield 4 in the present invention abandons the rocker, so it occupies less space, thereby providing more flexible conditions for the layout design of the shield 4. Here, one of the points of force of the power spring 15 acts on the drive gear 13 (such as Figure 19 As shown), another point of force of the power spring 15 can fall on the base 3 or on the helmet shell body 1 (not shown in the figure), wherein the influence of the force exerted by the power spring 15 always forces the shield 4 to make an open posture, of course, this posture is achieved by transmitting through the engagement of the drive gear 13 and the rack 14. It should be noted that the power spring 15 in the present invention can be in the form of either a tension-action type or a pressure-action type, and in particular, it can also be a torsion-action type, wherein the torsion-action type is the preferred form, because the torsion-action type can effectively utilize the body space of the drive gear 13 for reasonable layout. It is particularly important to point out that the shield 4 in the present invention can adopt such a better design layout strategy: when the jaw guard 2 is in the position state of the full helmet structure, the lower edge 4b ​​of the shield 4 can be fastened to the jaw guard 2, and the upper edge 4c of the shield 4 can be fastened to the helmet shell body 1 (as shown in the figure). Figures 1 to 3 When the shield 4 is in the fully opened position, the jaw guard 2 can make a crossing action over the shield 4 in this state to complete the state conversion between the full helmet structure position and the half helmet structure position.

[0048] Further, in order to ensure that the shield 4 is in the buckled state (that is, the shield 4 is located in front of the helmet and is in a position to block the wind, sand and rain from directly blowing to the wearer's eyes and nose), see Figures 1 to 3 ) It can be firmly maintained in the buckled position. The present invention can configure a locking tooth mechanism on the base 3 and / or the helmet shell body 1. The locking tooth mechanism includes an external locking tooth 14a provided on the rack 14, an internal locking tooth 14b equipped on the base 3 or the helmet shell body 1, and a locking tooth spring 14c (see Figure 4 and Figure 19 ), the body of the inner snap-tooth 14b is constrained by the base 3 and / or the helmet shell body 1 and under its constraint, the movement of the inner snap-tooth 14b is in the form of linear displacement, or in the form of swinging displacement, or in the form of a composite displacement including linear displacement and swinging displacement, wherein the elastic force of the lock tooth spring 14c always forces the inner snap-tooth 14b to press against the outer snap-tooth 14a. It is particularly important to point out that the tooth structure of the inner snap-tooth 14b and the outer snap-tooth 14a in the present invention can adopt a one-to-two or two-to-two matching meshing mode, the so-called one-to-two is a single protruding tooth type inner snap-tooth 14b matched with two protruding tooth type outer snap-tooth 14a (such as 4 and Figure 19 As shown), or a single protruding tooth type external tooth 14a is matched with two protruding tooth type internal teeth 14b (not shown in the figure), the so-called two-to-two is two protruding tooth type internal teeth 14b are matched with two protruding tooth type external teeth 14a (not shown in the figure), or two protruding tooth type external teeth 14a are matched with two protruding tooth type internal teeth 14b (not shown in the figure); Figure 19 In the situation shown in (a), the guard 4 is locked in the fully buckled position by the locking gear mechanism, that is, the lower edge 4b ​​of the guard 4 is in contact with the guard jaw 2 (the inner locking teeth 14b and the outer locking teeth 14a are in meshing state). At this time, the guard 4 is most suitable for use when riding; Figure 19 In the situation shown in (b), the shield 4 is locked in the slightly open position by the locking gear mechanism, that is, the lower edge 4b ​​of the shield 4 is separated from the jaw guard 2 (but the inner locking teeth 14b and the outer locking teeth 14a are also in a meshing state). At this time, the shield 4 can take advantage of its slightly open condition to allow external air to blow into the interior of the helmet to remove the mist formed on the shield 4 due to breathing, which is beneficial to safe driving; Figure 19In the situation shown in (c), the shield 4 has been unlocked and has been bounced up to the fully opened position under the drive of the power spring 15 (the inner locking teeth 14b and the outer locking teeth 14a are now completely out of engagement). This state of the shield 4 is most suitable for the rider to use when taking a break. Here, the locking tooth spring 14c can be in the form of a tension-action type, a pressure-action type, or a torsion-action type, among which the pressure-action type is preferably arranged. In the present invention, when the inner locking teeth 14b are locked by the outer locking teeth 14a, the shield 4 will be maintained in a certain current position, such as Figure 19 (a) and Figure 19 As shown in (b), when the inner latching teeth 14b are released from the outer latching teeth 14a and unlocked, the shield 4 can be driven by the power spring 15 to be opened. Figure 19 (c) As shown. Furthermore, the present invention is provided with an unlocking mechanism on the base 3 and / or the helmet shell body 1, and the unlocking mechanism comprises a tongue 17 and a retaining spring 18, see Figure 4 and Figure 19 (a), wherein the pressing tongue 17 includes an inclined push surface 17a and is arranged between the first sink 11a and the second sink 11d. When the jaw guard 2 moves from the half-helmet configuration position to the full-helmet configuration position, the bearing plate 9 can contact the inclined push surface 17a of the pressing tongue 17 and overcome the elastic force of the retaining spring 18 to force the pressing tongue 17 to give way. The giving way of the pressing tongue 17 can drive the inner latching tooth 14b to disengage the outer latching tooth 14a to unlock the locking tooth mechanism; see Figure 4 and Figure 19 The pressing tongue 17 can press the inclined groove 14c on the inner tooth 14b through the force transmission pin 17b set thereon, and drive the inner tooth 14b to disengage from the outer tooth 14a by this pressing action. In addition, other structures and transmission methods can also be used to achieve this function.

[0049] In order to prevent the shield 4 from being accidentally opened due to impact or unintentional contact when the shield 4 is fully fastened to the chin guard 2, the present invention can provide a locking and unlocking mechanism for the shield 4 at the lower edge 4b ​​of the shield 4 and on the main body of the chin guard 2, thereby improving the reliability and safety of the helmet. The locking and unlocking mechanism includes an inner buckle structure provided at the lower edge 4b ​​of the shield 4 and an outer buckle structure provided on the main body of the chin guard 2, and the inner buckle structure and the outer buckle structure correspond to each other; wherein the inner buckle structure includes a snap structure 4d, and the outer buckle structure includes a bougie 19 that can be forced to give way, and a locking hook 19a (such as a hook 19a) provided on the bougie 19. Figure 20As shown); in addition, the locking and unlocking mechanism of the present invention further includes a first unlocking key 20 and / or a second unlocking key 21, and the first unlocking key 20 and the second unlocking key 21 are both arranged on the body of the jaw guard 2 and can both serve as actuating members for unlocking the shield 4, wherein the first unlocking key 20 is arranged adjacent to the bougie 19 and can touch the bougie 19 during its actuation, and the second unlocking key 21 can unlock the jaw guard 2 in the full helmet structure position, and can manipulate the bougie 19 during its actuation, and when the first unlocking key 20 and / or the second unlocking key 21 touch the bougie 19, they can both press or pull the bougie 19 to open. 9 makes a giving way action; the best layout strategy of the first release button 20 and the second release button 21 described in the present invention is that their structures intersect with the symmetry plane P of the helmet shell body 1, or in other words, their structures intersect with the intersection line S; here, the present invention can adopt a manual action method to allow the first release button 20 and the second release button 21 to return to their original positions after they complete their actuation tasks. In particular, the present invention can also adopt the action form of spring elastic force to allow the first release button 20 and the second release button 21 to automatically return to their original positions after their actuation tasks are completed. For this purpose, a first reset spring 22 can be provided to help the first release button 20 to reset (such as Figure 21 As shown), and a second reset spring is provided to help the second release button 21 to reset (not shown in the figure); in the present invention, when the jaw guard 2 is in the full helmet structure position and the shield 4 is completely buckled on the jaw guard 2, the locking and release mechanism of the shield 4 can have three working conditions: a) when the first release button 20 and the second release button 21 are not touched, the lock hook 19a on the bougie 19 is in the original position, and the lock hook 19a in the original position can hook to the buckle structure 4d of the inner buckle structure and can lock the shield 4 accordingly. Figure 21 (a); b) when the first release button 20 is actuated, the first release button 20 can touch the bougie 19, and by the touch behavior can cause the lock hook 19a of the bougie 19 to be separated from its original position and thereby unfasten the shield 4 as shown Figure 21 (b) As shown, the first return spring 22 described here can help the first trip button 20 return to its original position or keep the first trip button 20 in its original position under normal conditions; c) when the second trip button 21 is actuated, the second trip button 21 can drive the bougie 19, and through this driving behavior, the lock hook 19a of the bougie 19 can be caused to leave its original position, thereby unfastening the shield 4 as shown in FIG. Figure 21 As shown in (c), the second return spring described here can help the second release button 21 return to its original position or keep the second release button 21 in its original position under normal conditions. Figure 21In the situation shown in (c), the second release button 21 is manually pulled away from its original position and drives the bougie 19 through an intermediate hook 23, thereby causing the bougie 19 to move away from its original position. However, at this time, the first release button 20 can still remain in its original position without being pressed. The second release button 21 of the present invention achieves its actuation by swinging around the rotating shaft 21a, wherein the rotating shaft 21a is constrained by the seat hole 24a on the base plate 24. The seat hole 24a can be a complete circular hole structure (not shown in the figure) or a partial circular hole structure (such as Figure 20 As shown), in addition, the base plate 24 is fastened to the body of the jaw guard 2 or the base plate 24 and the body of the jaw guard 2 are made into an integral structure. Figure 20 and Figure 21 In the embodiment shown, the draw hook 23 drives the bougie 19 by hooking the draw hole 19c on the bougie 19 body. The best structural form of the draw hole 19c here is a waist-shaped structure, because such a structure can form a larger redundant space and can more effectively avoid interference; the bougie 19 in the present invention can achieve the displacement action by swinging around the rotating pin 19b on its body, and the rotating pin 19b can be rotatably assembled on the base 25, wherein the base 25 is fastened to or integrally made of the structure on the body of the jaw guard 2; In addition, it should be noted that in order to allow the bougie 19 to reliably return to its original position when it is not controlled by the first release key 20 and / or the second release key 21, the present invention can also provide a third return spring 26 (such as Figure 20 and Figure 21 As shown), one end of the third return spring 26 rests on the bougie 19, and the other end thereof can rest directly or indirectly on the body of the jaw guard 2; it should be noted that the actuating action of the first trip button 20 and the actuating action of the second trip button 21 can be performed separately or in combination, that is, the giving way action performed by them to allow the bougie 19 to complete does not interfere with each other; it should also be noted that the action of the first trip button 20 touching the bougie 19 can be a direct drive method (such as Figure 21 As shown), it can also be driven indirectly, that is, by means of other parts or mechanisms (not shown in the figure); In addition, the lock hook 19a can have a variety of forms, such as a wedge-shaped structure (such as Figure 21 As shown) can also be in the form of a card edge or a clasp (not shown in the figure), in addition, in order to ensure the consistency of the lock hook 19a in place, a positioning card edge 2b can also be provided on the body of the jaw guard 2 (see Figure 21), the positioning card edge 2b can be used to effectively ensure that the lock hook 19a is in the correct position during assembly. The first release button 20 in the present invention can be arranged at the upper lip edge of the jaw guard 2. The advantage of such an arrangement is that when the shield 4 is completely fastened to the jaw guard 2, the first release button 20 is located adjacent to the inner buckle structure of the shield 4. When it is necessary to use fresh air outside the helmet to remove the fog inside the helmet, the shield 4 can be unlocked by manually pressing the first release button 20 to trigger the bougie 19 to complete the giving action. At the same time, the shield 4 can be pushed with a finger to force it to produce a slight displacement, thereby creating a breathable gap 27 between the lower edge 4b ​​of the shield 4 and the jaw guard 2. Figure 19 As shown in (b), this can improve safety when driving while wearing a helmet.

[0050] The outstanding advantage of the present invention over the prior art is that a stationary gear 5 and a rotating gear 6 are configured on the helmet shell body 1, and a rotating column 7 is provided on the fork handle 2a of the jaw guard 2 that can make a telescopic displacement relative to the rotating gear 6, and a track groove 11 including a first sink 11a and a first slope 11b is provided on the base 3 or / and the helmet shell body 1. On the one hand, the key structure 67 provided on the rotating gear 6 and the rotating column 7 is engaged, and the gear engagement of the stationary gear 5 and the rotating gear 6 is combined to constrain and achieve the rotation of the jaw guard 2. On the other hand, the first slope 11b of the track groove 11 is used to constrain and combine with the telescopic movement of the rotating column 7 to achieve the displacement movement of the fork handle 2a of the chin guard 2 relative to the symmetry plane P of the helmet shell body 1. In other words, the fork handle body of the chin guard 2 can be displaced away from the symmetry plane P of the helmet shell body 1 during the process of being opened and separated from the full-face helmet structure, and the fork handle 2a can be displaced close to the symmetry plane P of the helmet shell body 1 during the process of the chin guard 2 returning to its full-face helmet structure. Compared with the traditional variable chin guard structure helmet, the variable chin guard helmet of the present invention, on the one hand, when the chin guard 2 is flipped, its fork handle 2a can be extended outward to avoid the restraint of the helmet shell body 1 and the shield 4, thereby not affecting its conversion between the full helmet structure position and the half helmet structure position; on the other hand, when the chin guard 2 is in the full helmet structure position, its fork handle 2a can be in a retracted structure state relative to the helmet shell body 1, thereby bringing the following benefits: first, in the working condition of the full helmet structure which is commonly worn by drivers, the fork handle 2a of the chin guard 2 can become one with the helmet shell body 1, thereby eliminating the traditional variable chin guard structure. The chin guard structure has a protruding fork handle 2a, which is arranged outwardly. Therefore, the whistling sound of airflow caused by the protruding fork handle 2a on the surface of the helmet when driving can be effectively eliminated, so the wearing comfort of the helmet is improved, and the volume of the helmet is also reduced, so its storage capacity is also better; secondly, the chin guard 2 with a sunken structure in the full helmet structure position can directly rest its fork handle 2a on the helmet shell body 1, so when the chin guard 2 is impacted or colliding, its force can be directly transmitted to the helmet shell body 1, which will inevitably greatly improve the safety and reliability of the helmet.

[0051] The above embodiments are only some preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A gear-constrained variable jaw guard helmet, comprising a helmet shell body, a jaw guard, two bases and a shield, wherein the helmet shell body has a symmetrical plane, the two bases are separated by the symmetrical plane and are disposed on two side surfaces of the helmet shell body, and the two bases are fastened to the helmet shell body or are integrally formed with the helmet shell body, the jaw guard has two fork handles, and the two fork handles are disposed on two sides of the helmet shell body; stationary gears and rotating gears are disposed on both sides of the helmet shell body, the stationary gears are internally toothed gears and are stationary relative to the helmet shell body, and the rotating gears are externally toothed gears and can be changed in position relative to the helmet shell body; and the characteristics are as follows: The stationary gear, rotating gear, fork handle and base bracket arranged on the same side of the helmet shell body, together constitute a constraint mechanism that can change the position and posture of the jaw guard, wherein the fork handle in the constraint mechanism includes a columnar rotating column, the rotating column has a follower axis that is stationary relative to the fork handle, and a first key-type structure is provided on the rotating column, the axis of the rotating gear is coaxially arranged with the follower axis, and a second key-type structure is also provided on the rotating gear; the stationary gear and the rotating gear belonging to the same constraint mechanism are engaged with each other, and the rotating column and the rotating gear belonging to the same constraint mechanism are engaged with each other through the first key-type structure and the second key-type structure; a through-shaped groove rail is provided on the base bracket, and the rotating column is in a layout form that passes through the groove rail, the groove rail includes a track edge and the track edge is in contact with the rotating gear or / and the rotating column, and the groove rail can use this contact behavior to cause the rotating gear to maintain engagement with the stationary gear; when the jaw guard changes its position and posture and moves, the rotating column follows the fork handle The fork handle and the rotating column can also make telescopic displacement along the direction of the following axis relative to the rotating gear; a bearing plate is fastened or integrally made at the end of the rotating column, and an energy storage spring is provided between the bearing plate and the rotating gear on the same side of the helmet shell body; a track groove is provided on the base support or the helmet shell body, and the track groove includes a first sinking pit and a first slope, the bearing plate abuts against the track groove and can slide along the track groove; in response to the process stage of the chin guard being opened and separated from its full-helmet structure position, the bearing plate has the behavior of separating from the first pit, and it has a contact behavior with the first slope of the track groove, and at the same time, the contact behavior enables the bearing plate to overcome the elastic force of the energy storage spring and prompt the fork handle of the chin guard to produce an opening displacement action away from the symmetrical plane of the helmet shell body through the rotating column; in response to the process stage of the chin guard returning to its full-helmet structure position, the bearing plate keeps in contact with the first slope under the elastic force of the energy storage spring and slides to the first pit along the first slope, and at the same time, the bearing plate prompts the fork handle of the chin guard to make a closing displacement action close to the symmetrical plane of the helmet shell body through the rotating column under the pressure of the energy storage spring.

2. The gear-constrained variable jaw guard helmet according to claim 1, characterized in that: The following axes of the rotating columns disposed on both sides of the helmet shell body are coaxially arranged, and the following axes are arranged perpendicular to the symmetry plane of the helmet shell body.

3. The gear-constrained variable jaw guard helmet according to claim 2, characterized in that: A latch is provided on the base or the helmet shell body. When the chin guard is in the full helmet structure position and is observed along the follower axis toward the symmetry plane of the helmet shell body, the latch is located farther away from the symmetry plane of the helmet shell body than the force-bearing plate, and when the latch and the force-bearing plate are orthographically projected onto the symmetry plane of the helmet shell body, their projections intersect.

4. The gear-constrained variable jaw guard helmet according to claim 3, characterized in that: The energy storage spring is a conical spring.

5. The gear-constrained variable jaw guard helmet according to claim 4, characterized in that: The key structures of the rotating gear and the rotating column are both straight-line structures. When the jaw guard changes its position and posture, the rotating gear and the fork have the same rotational angular velocity around the follower axis.

6. The gear-constrained variable jaw guard helmet according to claim 5, characterized in that: The track groove includes a second pit and a second slope. In response to the process stage of the chin guard flipping out of its half-helmet structure position, the force-bearing plate has the behavior of separating from the second pit, and it comes into contact with the second slope of the track groove. At the same time, through this contact behavior, the force-bearing plate can overcome the elastic force of the energy storage spring and prompt the fork handle of the chin guard to produce an opening displacement action away from the symmetrical plane of the helmet shell body through the rotating column; in response to the process stage of the chin guard approaching and seating in its half-helmet structure position, the force-bearing plate maintains contact with the second slope under the elastic force of the energy storage spring and slides toward the second pit along the second slope. At the same time, under the pressure of the energy storage spring, the force-bearing plate prompts the fork handle of the chin guard to make a closing displacement action close to the symmetrical plane of the helmet shell body through the rotating column.

7. The gear-constrained variable jaw guard helmet according to claim 6, characterized in that: When the chin guard is flipped from the full helmet structure position to the half helmet structure position, the angle through which the fork handle rotates relative to the helmet shell body is 180 degrees.

8. The gear-constrained variable jaw guard helmet according to claim 7, characterized in that: A design line is provided for the outer contour line obtained by projecting the fork handle on the symmetry plane of the helmet shell body. The design line falls on the symmetry plane and passes through a fixed point on the chin guard's orthographic projection. At the same time, an orthogonal line passing through the fixed point and perpendicular to the design line is provided on the symmetry plane, wherein the fixed point is the midpoint of the line connecting the two intersection points of the follower axis of the rotating column on the symmetry plane when the chin guard is in the full helmet structure position and the half helmet structure position. In addition, two boundary lines are provided, which are made by the two intersection points of the follower axis of the rotating column on the symmetry plane when the chin guard is in the full helmet structure position and the half helmet structure position respectively. Both boundary lines fall on the symmetry plane and are perpendicular to the design line. Then, the design principle of the outer contour line of the tail of the chin guard fork handle is: the outer contour lines of the orthographic projection of the fork handle located between the two boundary lines on the symmetry plane are symmetrically arranged with respect to the design line and the orthogonal line, and the design line L passes through the two intersection points.

9. The gear-constrained variable jaw guard helmet according to claim 8, characterized in that: The bearing plate and / or the connecting accessories of the bearing plate are made of magnetically attractive materials or are magnets, and magnets or magnetically attractive parts are provided on the helmet shell body or the base at positions corresponding to the first sinkhole and the second sinkhole.

10. The gear-constrained variable jaw guard helmet according to any one of claims 1 to 9, characterized in that: The shield includes two supporting sides, which are separated by the symmetrical plane and are located on both sides of the helmet shell body; at least one base includes an outer cover and a bottom cover, and a driving gear that can rotate on a fixed axis, a rack engaged with the driving gear, and a power spring that can drive the driving gear to rotate are equipped on this base or the helmet shell body. The rack is connected to the supporting sides of the shield, and an arc-shaped outer guide groove is provided on the outer cover and / or the helmet shell body, and an arc-shaped inner guide groove is provided on the bottom cover and / or the helmet shell body. The outer guide groove and the inner guide groove together constitute a constraint guide rail, and the constraint guide rail is used to constrain the position and posture of the rack.

11. The gear-constrained variable jaw guard helmet according to claim 10, characterized in that: A locking tooth mechanism is arranged on the base support and / or the helmet shell body, and the locking tooth mechanism includes an external tooth arranged on the rack, an internal tooth equipped on the base support or the helmet shell body, and a locking tooth spring. The body of the internal tooth is constrained by the base support and / or the helmet shell body and under its constraint, the movement of the internal tooth is expressed in the form of linear displacement, or in the form of swinging displacement, or in the form of a composite displacement including linear displacement and swinging displacement, wherein the elastic force of the locking tooth spring always tends to force the internal tooth to press against the external tooth.

12. The gear-constrained variable jaw guard helmet according to claim 11, characterized in that: An unlocking mechanism is arranged on the base support and / or the helmet shell body, and the unlocking mechanism includes a pressing tongue and a retaining spring. The pressing tongue includes an inclined push surface and is arranged between the first sink hole and the second sink hole. When the jaw guard moves from the half-helmet structure position to the full-helmet structure position, the bearing plate can contact the inclined push surface of the pressing tongue and force the pressing tongue to make a giving motion. The giving motion of the pressing tongue can drive the inner locking teeth to disengage from the outer locking teeth to unlock the locking tooth mechanism.

13. The gear-constrained variable jaw guard helmet according to any one of claims 1 to 9, characterized in that: A shield locking and releasing mechanism is provided at the lower edge of the shield and on the main body of the jaw guard. The shield locking and releasing mechanism includes an inner buckle structure provided at the lower edge of the shield and an outer buckle structure provided on the main body of the jaw guard. The inner buckle structure includes a snap structure, and the outer buckle structure includes a bougie that can be forced to give way and a lock hook arranged on the bougie. In addition, the shield locking and releasing mechanism also includes a first release key and / or a second release key. The first release key and the second release key are both provided on the main body of the jaw guard and can both be used as release keys. An actuating member for the shield, wherein a first release button is disposed adjacent to a bougie and can contact the bougie during actuation of the first release button, and a second release button can release the chin guard in a full-face helmet configuration and can manipulate the bougie during actuation of the second release button; when the chin guard is in the full-face helmet configuration and the shield is fully engaged with the chin guard, the shield locking and releasing mechanism can have three operating conditions: a) when neither the first release button nor the second release button is actuated, the locking hook on the bougie is in an original position, and the locking hook in the original position can engage with the buckle structure of the inner buckle structure and thereby lock the shield; b) when the first trip button is actuated, the first trip button can touch the bougie, and through this touching behavior, the lock hook of the bougie can be disengaged from its original position, thereby releasing the protective cover; c) when the second trip button is actuated, the second trip button can drive the bougie, and through this driving behavior, the lock hook of the bougie can be disengaged from its original position, thereby releasing the protective cover.

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