CN116687093A

CN116687093A - Gear constraint type variable jaw-protecting helmet

Info

Publication number: CN116687093A
Application number: CN202310547613.6A
Authority: CN
Inventors: 万汉林; 刘新生; 李炎锋
Original assignee: JIANGMEN PENGCHENG HELMETS Ltd
Current assignee: JIANGMEN PENGCHENG HELMETS Ltd
Priority date: 2023-05-15
Filing date: 2023-05-15
Publication date: 2023-09-05

Abstract

The invention relates to a gear constraint type variable jaw-protecting helmet, which is characterized in that a static gear and a rotating gear are arranged, a rotating column capable of performing telescopic displacement motion relative to the rotating gear is arranged, and a track groove comprising a first slope is formed in a base or/and a helmet shell body, wherein on one hand, the position and the posture of a jaw are changed when the jaw is rotated by utilizing the meshing of a key structure formed in the rotating gear and the rotating column and combining the meshing of the static gear and the gear of the rotating gear, and on the other hand, the opening and closing displacement motion of a fork pair relative to the symmetrical surface of the helmet shell body is achieved by utilizing the constraint of the first slope of the track groove, the action of an energy storage spring and the telescopic motion of the rotating column. Because the fork handles of the jaw guard can be folded when the jaw guard is in the whole helmet structure position, the air flow whistle can be reduced, the volume is reduced, and the comfort and the storability of the helmet are improved; meanwhile, the folding fork handle can also directly transmit the impact force received by the jaw guard to the helmet shell body, so that the stress characteristic can be improved, and the safety and the firmness of the helmet can be improved.

Description

Gear constraint type variable jaw-protecting helmet

Technical Field

The invention belongs to the technical field of helmet design, relates to a helmet with a jaw protection structure, in particular to a variable jaw protection type helmet with a jaw protection structure capable of being switched between a full helmet position and a half helmet position, and more particularly relates to a variable jaw protection type helmet which is capable of realizing structural switching of a jaw between the full helmet position and the half helmet position based on gear constraint and enabling a jaw protection fork handle to make opening and closing displacement actions timely.

Background

It is well known that in many situations people need to wear helmets to protect their head, such as motor cycles and racing vehicles, etc. Currently, the types of helmets mainly include a full-helmet structure type helmet and a half-helmet structure type helmet. The full-helmet structure type helmet is provided with a jaw guard encircling the chin of a user, so that the safety of the whole head of the wearer can be effectively protected; the semi-helmet structure type helmet does not have the jaw, so that the mouth and the nose of a wearer are exposed, and the helmet is convenient for drinking water, talking and the like. Needless to say, the helmet of the full helmet structure has sufficient safety protection function, but is poor in use comfort, and the helmet of the half helmet structure has good use comfort, but has poor safety protection function. A variable jaw-protection type helmet having the advantages of both full-helmet structure type helmet and half-helmet structure type helmet is presented, and the jaw of the helmet can be switched between the full-helmet position and the half-helmet position according to the requirement, such as spanish patent application ES2329494T3 and chinese patent applications CN105901820A, CN109875177a and CN114158814A filed by the applicant of the present patent application, and the helmets related to the variable jaw-protection type helmet.

However, there is a common problem with the prior art variable jaw-protecting helmets, in which the two handles of the jaw-protecting helmets are arranged in a convex manner with respect to the helmet shell body, and the reason for this arrangement is that the jaw-protecting helmets must avoid the catch of the helmet shell body to achieve the posture change. However, such a fork handle with a convex arrangement results in a helmet with disadvantages: 1) The convex-layout-shaped fork handles can cause the pneumatic performance of the helmet to be degraded, because the jaw-protecting fork handles protruding out of the helmet shell body inevitably generate turbulence in the riding process of a wearer so as to generate additional wind resistance, and the wind resistance can not only cause unnecessary resistance, but also can negatively influence the wearing firmness of the helmet; 2) The convex layout-shaped fork handles can cause the wearing comfort of the helmet to be poor, and also can generate uncomfortable airflow whistle when a wearer rides due to the turbulence effect generated by the jaw-protecting fork handles which protrude out of the helmet shell body for layout, in other words, the wearing comfort of the wearer is adversely affected; 3) It is apparent that the convex layout of the prongs also results in an increase in the volume of the helmet. The helmet is relatively large in size, so that the weight of the helmet is heavier to increase the load of a wearer, and the wearer is easy to fatigue, and the storage space of the helmet is large due to the large size of the helmet, which is obviously disadvantageous to storage, transportation and storage; 4) The fork handle with the convex layout has the defect that the structural bearing force of the helmet is weakened, and the reason is that when the helmet is impacted by external strong collision, the impact force generated by the jaw protector cannot be directly transmitted to the helmet shell body by utilizing the fork handle body, but is indirectly and misplaced transmitted to the helmet shell body through the middle connecting piece, so that the jaw protector has poor impact resistance and certain potential safety hazard.

In summary, although the prior variable jaw-protecting structure type helmet can realize the structural conversion of the jaw between the full helmet position and the half helmet position, the structure is insufficient in aspects of firmness, comfort, safety, storage and the like due to the fork handles which are arranged in a protruding manner. In particular, there is room for further improvement and lifting in the prior art variable jaw structure helmets.

Disclosure of Invention

Aiming at the problems of the prior variable jaw-protecting structure helmet, the invention provides a gear-constrained variable jaw-protecting helmet, which aims at: the jaw-protecting fork handle is in a storage state at the whole helmet position or even at the half helmet position by improving the structural form and the driving mechanism of the jaw-protecting fork handle while restraining by the gears and achieving the conversion of the jaw-protecting position and the gesture, so that the firmness, the comfort, the safety and the storage of the helmet can be effectively improved.

The purpose of the invention is realized in the following way: the gear-constrained jaw-protecting type helmet comprises a helmet shell body, a jaw, two holders and a shield, wherein the helmet shell body is provided with a symmetrical surface, the two holders are separated by the symmetrical surface and are separated from the two side surfaces of the helmet shell body, the two holders are fastened on the helmet shell body or are manufactured in an integral structure with the helmet shell body, the jaw is provided with two fork handles, and the two fork handles are separated from the two side surfaces of the helmet shell body; the helmet shell comprises a helmet shell body, wherein the helmet shell body is provided with a rotating gear and a stationary gear, the rotating gear is arranged on two side edges of the helmet shell body, the stationary gear is an internal tooth configuration gear, the stationary gear is in a stationary state relative to the helmet shell body, the rotating gear is an external tooth configuration gear, and the rotating gear can change position relative to the helmet shell body; the method is characterized in that: the helmet shell comprises a helmet shell body, a stationary gear, a rotating gear, a fork handle and a collet which are distributed on the same side of the helmet shell body, wherein the stationary gear, the rotating gear, the fork handle and the collet are jointly participated in forming a constraint mechanism capable of changing the position and the posture of a jaw, the fork handle in the constraint mechanism comprises a columnar rotating column, the rotating column is provided with a follow-up axis which is stationary relative to the fork handle, a key structure is arranged on the rotating column, the axis of the rotating gear is coaxial with the follow-up axis, and the key structure is also arranged on the rotating gear; the static gear and the rotating gear which belong to one constraint mechanism are engaged with each other, and the rotating column and the rotating gear which belong to one constraint mechanism are engaged with each other through the key structure; a through groove rail is arranged on the bottom support, the rotating column is in a layout form penetrating through the groove rail, the grooved rail comprises a rail edge, and the rail edge and the rotating gear or/and the rotating column have contact behaviors, and the grooved rail can be used for enabling the rotating gear to keep meshed with the static gear; when the jaw is moved by changing the position and the posture, the rotating column moves synchronously along with the fork handle, meanwhile, the rotating gear which is matched and meshed with the rotating column is driven by the rotating column to also start to rotate around the follow-up axis, and the fork handle and the rotating column can also perform telescopic displacement motion along the follow-up axis direction relative to the rotating gear; a bearing disc is fastened or integrally manufactured at the end part of the rotating column, and an energy storage spring is arranged between the bearing disc and the rotating gear at the same side of the helmet shell body; the support or/and helmet shell body is provided with a track groove, the track groove comprises a first pit and a first slope, and the bearing disc is abutted against the track groove and can slide along the track groove; the support plate has a behavior of separating from the first sinking pit and a contact behavior with the first slope of the track groove in the process stage of lifting the support plate from the full helmet structure position, and simultaneously the contact behavior enables the support plate to overcome the elasticity of the energy storage spring and promote the fork handle of the support plate to generate an opening displacement motion far away from the symmetrical plane of the helmet shell body through the rotating column; the support plate keeps contact with the first slope under the action of the elasticity of the energy storage spring and slides to the first sinking pit along the first slope, and simultaneously the support plate promotes the fork handle of the support plate to perform folding displacement action close to the symmetrical plane of the helmet shell body through the rotating column under the compression of the energy storage spring.

Further, the following axes of the rotating posts which are respectively arranged at the two sides of the helmet shell body are coaxially arranged, and the following axes and the symmetrical surface of the helmet shell body are vertically distributed.

Further, the shoe or/and the helmet shell body is provided with the clamping tongue, when the jaw is in the state of the whole helmet structure and is observed along the follow-up axis direction towards the symmetry plane of the helmet shell body, the clamping tongue is located at a position farther from the symmetry plane of the helmet shell body than the bearing disc, and the clamping tongue and the bearing disc are projected to the symmetry plane of the helmet shell body in an orthogonal projection mode.

Further, the energy storage spring is a conical spring.

Further, the key structures of the rotating gear and the rotating column are in straight line structures, and when the positions and the postures of the jaw guard are changed, the rotating gear and the fork handle have the same rotating angular speed around the follow-up axis.

Further, the track groove comprises a second sinking pit and a second slope, the support plate has a behavior of being separated from the second sinking pit when the support plate is turned over and separated from the half helmet structure position, and is contacted with the second slope of the track groove, and meanwhile, the support plate can overcome the elasticity of the energy storage spring and promote the fork handle of the support plate to generate an opening displacement motion far away from the symmetrical plane of the helmet shell body through the rotating column by virtue of the contact behavior; the support plate keeps contact with the second slope under the action of the elasticity of the energy storage spring and slides to the second sinking pit along the second slope, and simultaneously the support plate promotes the fork handle of the support plate to perform folding displacement action close to the symmetrical plane of the helmet shell body through the rotating column under the compression of the energy storage spring.

Further, the jaw is rotated 180 ° relative to the helmet shell body by its fork handle when it is flipped from the full helmet configuration position to the half helmet configuration position.

Furthermore, the jaw guard is provided with a design line aiming at an outer contour line obtained by orthographic projection of the fork handle on a symmetrical surface of the helmet shell body, the design line falls on the symmetrical surface and passes through an immobile point on the orthographic projection of the jaw guard, and meanwhile, the symmetrical surface is provided with an orthogonal line passing through the immobile point and being perpendicular to the design line, wherein the immobile point is a connecting midpoint of two intersection points on the symmetrical surface of the jaw guard when the jaw guard is in a full helmet structure position and a half helmet structure position, and the jaw guard is provided with two boundary lines which are respectively formed by two intersection points on the symmetrical surface of the jaw guard when the jaw guard is in the full helmet structure position and the half helmet structure position, and the two boundary lines fall on the symmetrical surface and are perpendicular to the design line, so that the design principle of the tail profile line of the jaw guard fork is as follows: the fork handle orthographic projection outline lines positioned between the two boundary lines on the symmetrical plane are symmetrically distributed about the design line and the orthogonal line.

Furthermore, the force bearing disc and/or the connecting accessory of the force bearing disc are/is made of a magnetic attraction material or are made of a magnet, and the positions of the helmet shell body or the bottom support corresponding to the first sinking pit and the second sinking pit are provided with magnets or magnetic attraction parts.

The shield comprises two supporting side edges which are separated by the symmetrical plane and are arranged beside the two sides of the helmet shell body; at least one bottom support comprises an outer cover and a bottom cover, a driving gear capable of rotating by a fixed shaft, a rack meshed with the driving gear and a power spring capable of driving the driving gear to rotate are assembled on the bottom support or the helmet shell body, the rack is connected with the supporting side edge of the protective cover, an arc-shaped outer guide groove is formed in the outer cover or/and the helmet shell body, an arc-shaped inner guide groove is formed in the bottom cover or/and the helmet shell body, and the outer guide groove and the inner guide groove are combined together to form a pair of constraint guide rails, so that the position and the posture of the rack are constrained by the constraint guide rails.

Further, the shoe or/and helmet shell body is provided with a tooth locking mechanism, the tooth locking mechanism comprises an outer tooth arranged on the rack, an inner tooth assembled on the shoe or helmet shell body and a tooth locking spring, the body of the inner tooth is restrained by the shoe or/and helmet shell body, and the movement of the inner tooth is in a linear displacement form, or in a swinging displacement form, or in a composite displacement form comprising linear displacement and swinging displacement, wherein the action trend of the elastic force of the tooth locking spring always forces the inner tooth to abut against the outer tooth.

Further, an unlocking mechanism is configured on the base or/and the helmet shell body, the unlocking mechanism comprises a pressing tongue and a retaining spring, the pressing tongue comprises an inclined pushing surface and is arranged between the first sinking pit and the second sinking pit, when the jaw protector advances from the half helmet structure position to the full-pattern structure position, the bearing disc can contact the inclined pushing surface of the pressing tongue and can force the pressing tongue to make a yielding action, and the pressing tongue can drive the inner clamping teeth to be separated from the outer clamping teeth to unlock the locking tooth mechanism.

The protective cover lock catch and release mechanism comprises an inner buckle structure arranged at the lower edge part of the protective cover and an outer buckle structure arranged on the protective jaw body, wherein the inner buckle structure comprises a buckle structure, and the outer buckle structure comprises a bougie capable of being forced to be abducted and a lock hook arranged on the bougie; in addition, the shield lock and unlock mechanism further comprises a first unlock key or/and a second unlock key, wherein the first unlock key and the second unlock key are both arranged on the body of the jaw guard and can be used as an actuating piece of the unlock shield, the first unlock key is arranged adjacent to the bougie and can touch the bougie during the actuation of the first unlock key, and the second unlock key can unlock the jaw guard in the full helmet structure position and can be controlled to the bougie during the actuation of the second unlock key; when the jaw is in the whole helmet structure position and the shield is completely buckled on the jaw, the shield lock catch and the unbuckling mechanism can have three working conditions: a) When the first unbuckling key and the second unbuckling key are not touched, the lock hook on the bougie is positioned at the original position, and the lock hook positioned at the original position can be hooked on the buckle structure of the inner buckle structure and can lock the shield according to the buckle structure; b) When the first unlocking lock is actuated, the first unlocking key can touch the bougie, and the lock hook of the bougie can be driven to be separated from the original position through the touch action, so that the shield is unlocked accordingly; c) The second trip key is capable of driving the bougie during actuation of the second trip key and, by virtue of this driving action, of causing the lock catch of the bougie to disengage from its original position, thereby tripping the shield.

The invention relates to a gear constraint type variable jaw-protecting type helmet, which is characterized in that a stationary gear and a rotary gear are arranged on a helmet shell body, a rotary column capable of performing telescopic displacement motion relative to the rotary gear is arranged on a jaw-protecting fork handle, a track groove comprising a first sinking pit and a first slope is arranged on a base or/and the helmet shell body, on one hand, the rotary gear and the rotary column are meshed by key structures arranged on the rotary gear and the rotary column and combined with the gear meshing of the stationary gear and the rotary gear to restrain and achieve the rotation type position and posture change of a jaw, on the other hand, the jaw-protecting fork handle is restrained by the first slope of the track groove and combined with the telescopic motion of the rotary column to achieve the displacement motion of opening and closing relative to the symmetrical surface of the helmet shell body, in other words, the jaw-protecting fork handle body has the displacement motion far away from the symmetrical surface of the helmet shell body in the process of opening and separating from the helmet shell body, and the jaw-protecting fork handle body has the displacement motion close to the symmetrical surface of the helmet shell body in the process of returning to the seated helmet shell structure position. Compared with the traditional variable jaw-protecting structure helmet, the fork handle of the variable jaw-protecting helmet can be outwards stretched to avoid the catch of the helmet shell body and the shield when the jaw-protecting structure helmet is turned over so as not to influence the conversion between the full helmet structure position and the half helmet structure position, and on the other hand, the fork handle of the variable jaw-protecting structure helmet can be in a sinking and folding structure state relative to the helmet shell body when the jaw-protecting structure is positioned at the full helmet structure position, so that the variable jaw-protecting structure helmet has the advantages that: firstly, under the common driving wearing working condition of a full helmet structure, the jaw-protecting fork handle can be integrated with the helmet shell body to eliminate the protruding fork handle layout form of the traditional variable jaw-protecting structure, so that the air flow whistle caused by the fork handle with excessively protruding appearance of the helmet during driving can be effectively eliminated, the wearing comfort of the helmet is improved, and the size of the helmet is reduced to ensure that the storage of the helmet is better; secondly, the jaw protector with the sinking structure layout can directly support the fork handle body on the helmet shell body when the whole helmet structure is positioned, so that the stress of the jaw protector can be directly transmitted to the helmet shell body when the jaw protector is impacted and collided, and the safety and the firmness of the helmet in use can be improved greatly.

Drawings

FIG. 1 is an isometric view of a gear-constrained variable jaw-guard helmet of the present invention with the jaw in the full helmet configuration and the shield in the fully-closed position;

FIG. 2 is a schematic side view of the gear-constrained variable jaw-protection helmet of the present invention in the state shown in FIG. 1;

FIG. 3 is a schematic front view of the gear-constrained variable jaw-protection helmet of the present invention in the state shown in FIG. 1;

FIG. 4 is an exploded view of the main components of a gear-constrained variable jaw-guard helmet of the present invention;

FIG. 5 is a schematic diagram illustrating a layout of a gear constrained variable jaw helmet of the present invention comprising both stationary gears and rotating gears engaged with each other;

FIG. 6 is a schematic view of a gear-constrained variable jaw guard helmet of the present invention with the rotating gears in different positions;

FIG. 7 is a schematic side view of a gear-constrained variable jaw-guard helmet of the present invention with the jaw in a full helmet configuration reflecting the placement of the slotted track on the shoe;

FIG. 8 is a cross-sectional view taken along the path of movement of the gear-constrained variable jaw guard helmet of the present invention along the follower axis in the state shown in FIG. 7, taken along A-A;

FIG. 9 is a T-view of a gear-constrained variable jaw-guard helmet of the present invention in the state shown in FIG. 7;

FIG. 10 is a schematic side view of a gear-constrained variable jaw-guard helmet of the present invention with the jaws thereof in a position to clear the dome of the helmet shell body;

FIG. 11 is a cross-sectional view taken along the path of movement of the gear-constrained variable jaw guard helmet of the present invention along the follower axis in the state shown in FIG. 10, taken along A-A;

FIG. 12 is a T-view of a gear-constrained variable jaw-guard helmet of the present invention in the state shown in FIG. 10;

FIG. 13 is an isometric view of a gear-constrained variable jaw-guard helmet of the present invention with the jaw in a semi-helmet configuration and the shield in a fully-closed position;

FIG. 14 is a schematic side view of a gear-constrained variable jaw-guard helmet of the present invention in the state shown in FIG. 13;

FIG. 15 is a schematic front view of the gear-constrained variable jaw-protection helmet of the present invention in the state shown in FIG. 13;

FIG. 16 is a schematic side view of a gear-constrained variable jaw-guard helmet of the present invention with the jaw in a semi-helmet configuration and the shield in a fully open position;

FIG. 17 is a schematic illustration of the change in process state of a gear-constrained variable jaw-guard helmet of the present invention as its jaw transitions from a full helmet structural position to a semi-helmet structural position;

FIG. 18 is a schematic illustration of a gear constrained variable jaw helmet of the present invention with a jaw fork 2a tail outer profile design;

FIG. 19 is a schematic view of a gear-constrained variable jaw-guard helmet of the present invention provided with a shield automatic lifting device and a tooth locking mechanism for the shield and its different tooth locking states;

FIG. 20 is an exploded view of the assembly of the major components of the hood latch and unlatch mechanism of a gear-constrained variable jaw-guard helmet of the present invention;

fig. 21 is a schematic view illustrating a state of a shield lock and unlock mechanism of a gear-constrained variable jaw-guard helmet according to the present invention under typical working conditions.

Detailed Description

The invention is further described below with reference to the specific examples, see fig. 1-21:

the utility model provides a gear constraint formula variable jaw protection helmet, it includes a helmet shell body 1, a jaw 2, two collet 3 and a guard shield 4 (see fig. 4), helmet shell body 1 have a symmetry plane P, two collet 3 separate and put the both sides face of helmet shell body 1 by this symmetry plane P, and these two collet 3 are fastened on helmet shell body 1 or these two collet 3 and helmet shell body 1 structure as an organic whole make, the scene that the collet 3 is fastened with the screw and is installed on helmet shell body 1 is shown in fig. 1 to 3. Here, when the shoe 3 is fabricated in an integral structure with the helmet shell body 1, the shoe 3 may be regarded as a part of the helmet shell body 1; in addition, the base 3 may be a single integral part or a combined part formed by assembling a plurality of relatively independent parts, and the base 3 in fig. 4 includes an outer cover 3a and a bottom cover 3b as the combined part. The jaw 2 of the invention has two fork handles 2a, and the two fork handles 2a are arranged beside two sides of the helmet shell body 1 (see fig. 1 to 4); the two sides of the helmet shell body 1 are respectively provided with a static gear 5 and a rotating gear 6, the static gear 5 is an internally toothed configuration gear, the static gear 5 is in a static state relative to the helmet shell body 1, the rotating gear 6 is an externally toothed configuration gear, and the rotating gear 6 can change positions and attitudes relative to the helmet shell body 1, wherein the static gear 5 and the rotating gear 6 can be single-size gears (not shown in the figure) which respectively have only one reference circle, or multi-size gears which respectively have a plurality of reference circles, the situation shown in fig. 5 is that the static gear 5 is a composite gear formed by two sections of gear teeth comprising two reference circles R1 and R2, and the rotating gear 6 is also a composite gear formed by two sections of gear teeth comprising two reference circles, namely, the rotating gear 6 can change positions relative to the helmet shell body 1 and the other positions relative to the helmet shell body 6, and the situation shown in the situation that the positions relative to the helmet shell body 1 and the rest gear 6 are different from each other can be seen in the situation that the rest state of the helmet shell body 1 is not seen in the figure 1 is changed, and the situation is not seen in the rest state 1 is shown in the figure: one case is that the stationary gear 5 is a separately manufactured part or component which is then fastened to the helmet shell body 1 and/or the shoe 3 (not shown in the figures); in another case, the stationary gear 5 is made integrally with the helmet shell body 1 and/or the bottom support 3, and in the case shown in fig. 4, the stationary gear 5 is made integrally with the bottom support 3 (more specifically, the stationary gear 5 is made integrally with the outer cover 3a of the bottom support 3), and the stationary gear 5 may be regarded as a part of the bottom support 3, but the stationary gear 5 may also be made integrally with the bottom cover 3b of the bottom support 3 (not shown). It should be noted that, in the present invention, the function of the shield 4 is to prevent sand and rain from invading into the helmet to avoid negatively affecting the driving experience of the helmet wearer, and the main structure of the shield 4 is made of transparent material that does not obstruct the outward observation of the helmet wearer; in addition, the position of the shield 4 can be selected according to the requirement of a user, the operation of buckling and lifting can be completed manually, the shield 4 is in a completely buckled state when the jaw 2 is in the full helmet structure position in the situation shown in fig. 1 to 3, and the shield 4 can play the best role of preventing wind, sand and rain. Here, the term "the two prongs 2a are separated at both sides of the helmet shell body 1" means that the two prongs 2a are separated at both sides of the helmet shell body 1 by a symmetry plane P of the helmet shell body 1 (see fig. 3), wherein the symmetry plane P means such a plane (see fig. 1 to 4, 8 and 9, 11 to 13, 15): this symmetry plane P passes through the wearer' S mouth, nose and head top and separates the eyes and ears of the wearer on both sides thereof when the helmet is worn normally, i.e. said symmetry plane P is an imaginary plane having the properties of a split helmet shell body 1, while the layout on the same side of the helmet shell body 1 means being arranged on the same side of the symmetry plane P, while the symmetry plane P has an intersection S with the outermost surface of the helmet and with the outermost surfaces of parts and accessories (as shown in fig. 1, 3 and 4, fig. 9, fig. 12 and 13, fig. 15); in addition, the helmet shell body 1 is a generic term for the present invention to include both the main body of the helmet shell and the functional or decorative parts of various other components such as windows, covers, hangers, seals, fasteners, cushioning and energy absorbing elements, etc., which are fastened to or attached to the shell body. It should be noted that the best layout of the shoe 3 of the present invention is to be arranged at the side of the helmet shell body 1 (as shown in fig. 1 to 3, 5, 7, 9 and 10, 12 to 16) against or near the ears of the helmet wearer, and the best layout of the chin bar 2 is to be arranged with the bodies of its two prongs 2a spaced beside the sides of the symmetry plane P of the helmet shell body 1 and in correspondence with the parts of the shoe 3. The invention is characterized in that: the static gear 5, the rotating gear 6, the fork handle 2a and the bottom bracket 3 which are distributed on the same side of the helmet shell body 1 are jointly participated in forming a constraint mechanism capable of changing the position and the posture of the jaw 2, wherein the fork handle 2a in the constraint mechanism comprises a columnar rotating column 7 (see figure 4), the rotating column 7 is provided with a follow-up axis O1 which is static relative to the fork handle 2a, a key structure 67 (shown in figures 4 and 21) is arranged on the rotating column 7, the axis of the rotating gear 6 is coaxial with the follow-up axis O1, and a key structure 67 (shown in figure 4) is also arranged on the rotating gear 6, the rotating column 7 can be a separate piece (not shown in the figure) which is fixedly connected to the fork handle 2a, in addition, the rotating column 7 and the fork handle 2a can be manufactured as an integral structure (see figure 4), and in addition, the axis of the rotating gear 6 refers to the axis passing through the gear indexing circle center and being perpendicular to the axis of a circle indexing plane; here, the key-shaped structure 67 refers to various geometric structures with protrusions and depressions, and particularly includes a protrusion key or a key groove with a certain axial length, the sectional shape or sectional profile of the key-shaped structure 67 may be various forms such as a rectangular form, a tooth form, a cycloid form or a combination profile formed by combining various curves, the number of the key-shaped structures 67 may be one or two or more, typical key-shaped structures 67 are a convex spline and a concave key groove, etc., and in the case of fig. 4 and 21, the key-shaped structures 67 of the rotating post 7 and the rotating gear 6 are spline-shaped multiple key forms, it should be noted that the key-shaped structures 67 may be independent pieces and then fastened to the corresponding rotating gear 6 or the rotating post 7 (not shown in the drawings), and in addition, the key-shaped structures 67 may be integrally formed with the rotating gear 6 or the rotating post 7 (as shown in fig. 4); it should be emphasized that the key-shaped structure 67 may be a continuous structure such as a long-strip-shaped protruding key or key groove (see fig. 4), and the key-shaped structure 67 may be a discontinuous structure such as a single boss or protruding bead, and a plurality of intermittently arranged bosses or protruding beads (not shown in the figure), however, any structure can be considered as long as the structure can complete the circumferential transmission power and movement between the rotating gear 6 and the rotating post 7 when the rotating gear and the rotating post 7 are mutually matched, and can complete the axial relative telescopic action between the rotating gear and the rotating post when the rotating gear and the rotating post are mutually matched, which belongs to the category of the key-shaped structure 67 of the present invention; it should be noted that, in addition to the above-mentioned stationary gear 5, rotary gear 6, fork 2a and base 3, the restraining mechanism of the present invention may also have other components, for example, when the helmet shell body 1 has a restraining effect on the structural transformation of the chin 2, the helmet shell body 1 may also be regarded as participating in the restraining mechanism, that is, as long as it is a component and a part that have a restraining contribution to the change of the position and posture of the chin 2, they all can be regarded as participating together in the restraining mechanism that can change the position and posture of the chin 2; in the invention, the stationary gear 5 and the rotary gear 6 which belong to a constraint mechanism are engaged with each other, the rotary column 7 and the rotary gear 6 which belong to a constraint mechanism are engaged with each other (also called as snap fit) through the key structure 67 of the rotary column and the rotary gear 6, and the main characteristic of the engagement is that the engagement can transmit motion and power to each other, and particularly comprises linkage response of position and gesture; it should be noted that, when the stationary gear 5 and the rotating gear 6 are both composite gears formed by two segments of gear teeth including two reference circles, the gear tooth segments corresponding to each other form a meshing mating pair, as shown in fig. 5, the stationary gear 5 includes two reference circle radii R1 and R2, and the rotating gear 6 meshing with each other also includes two reference circle radii R1 and R2, so that the gear tooth segment of the stationary gear 5 corresponding to the reference circle radius R1 and the gear tooth segment of the rotating gear 6 corresponding to the reference circle radius R1 form a meshing pair, and the gear tooth segment of the stationary gear 5 corresponding to the reference circle radius R2 and the gear tooth segment of the rotating gear 6 corresponding to the reference circle radius R2 form a meshing pair (as shown in fig. 6); it should be also noted that, in the present invention, the key structures 67 of the rotating post 7 and the rotating gear 6 that are mutually matched are in a compatible matching form of "male-female type matching", that is, if the main structure of the key structure 67 of the rotating post 7 is a protruding key, the main structure of the key structure 67 of the rotating gear 6 that is mutually engaged with the protruding key is necessarily a recessed key slot, and vice versa; a through groove rail 8 is arranged on the bottom support 3, the groove rail 8 can be arranged on the outer cover 3a (shown in fig. 4) of the bottom support 3 or on the bottom cover 3b (not shown in the figure), and the rotating column 7 is in a layout form penetrating through the groove rail 8; the grooved rail 8 comprises at least one rail edge 8a, and the rail edge 8a has contact behavior with the rotating gear 6 and/or the rotating post 7, and the grooved rail 8 can be used for enabling the rotating gear 6 to keep meshed with the stationary gear 5, wherein the "the rail edge 8a has contact behavior with the rotating gear 6 and/or the rotating post 7" includes three situations: the first case is that the rail side 8a has a contact behavior with the turning gear 6 but it has no contact behavior with the turning post 7 (as shown in fig. 8, the rail side 8a has a contact with the boss flange 6a of the turning gear 6 in fig. 8), the second case is that the rail side 8a has a contact behavior with the turning post 7 but it has no contact behavior with the turning gear 6 (not shown), and the third case is that the rail side 8a has a contact behavior with both the turning gear 6 and the turning post 7 (not shown); when the jaw 2 changes position and posture to move (i.e. when the jaw 2 changes state between the two positions of the full helmet structure and the half helmet structure), the rotating post 7 moves synchronously along the following fork 2a, and then the following axis O1 also moves synchronously along the following fork as shown in fig. 6, while in the case of fig. 5 and 7, the moving track n of the following axis O1 is reflected to be an arc-shaped curve, and simultaneously the rotating gear 6 engaged with the rotating post 7 is driven by the rotating post 7 to also start to move rotationally around the following axis O1 (see fig. 6), and the fork 2a and the rotating post 7 can also perform telescopic displacement motion along the axial direction of the following axis O1 relative to the rotating gear 6, and the effect of the telescopic displacement can be obviously seen when comparing the two states shown in fig. 7 to 9 and 10 to 12, wherein fig. 8 is A-A along the moving track n of the following axis O1 shown in fig. 7, and fig. 9 is A-A along the moving track n of the following helmet shown in fig. 7 (see fig. 7 is A-A view of the following helmet in the state of fig. 7 is a-12), and the helmet is a view of the following helmet in the state of fig. 10-12 a is shown in the backward view of the following axis of fig. 7 a); in the scenario depicted in fig. 6: with the rotation of the rotary gear 6, on the one hand, the position of the following axis O1 is synchronously different relative to the base 3 (equivalent to the relative helmet shell body 1), and on the other hand, because the rotary gear 6 has a transmission relation with the rotary post 7 through the key structure 67 and further has a related motion relation with the fork handle 2a, the position and the posture of the rotary gear 6 reflected by fig. 6 (a) correspond to the jaw 2 and the fork handle 2a thereof to be in the full helmet structure position, the position and the posture of the rotary gear 6 reflected by fig. 6 (c) correspond to the jaw 2 and the fork handle 2a thereof to be in the half helmet structure position, and the position and the posture of the rotary gear 6 reflected by fig. 6 (b) correspond to the jaw 2 and the fork handle 2a thereof to be between the full helmet structure position and the half helmet structure position; here, since the rotating post 7 is fastened to or integrally formed with the fork handle 2a, it is obvious that they are synchronously moved together, and in addition, the rotating post 7 and the rotating gear 6 are engaged by the key-type structure 67, so that there is a coupled movement of the two, and as can be seen from fig. 6, the rotating gear 6 is not only varied in position but also varied in angle, in other words, the position and posture of the jaw 2 of the present invention can be controllably varied under the constraint of the stationary gear 5 and the rotating gear 6; it should be noted in particular that the rotary gear 6 of the present invention is a component capable of relative displacement along the axis O1 of the follower axis with respect to the fork 2a (comprising the rotary post 7), which is essential and necessary for the displacement of the fork 2a away from and towards the symmetry plane P of the helmet shell body 1, the main contribution of the present invention being: when the jaw 2 needs to be mutually converted between the full helmet structure position and the half helmet structure position, the jaw 2 can realize that the fork handle 2a presents a sinking structure layout (see fig. 7 to 9) in the full helmet structure position so as to be beneficial to improving the aerodynamic characteristics, the structural strength and the rigidity characteristics, the storage and transportation suitability of the helmet, and can change the fork handle 2a from a retracted state to an open state (see fig. 10 to 12) during the state of the structure conversion of the jaw 2 so as to avoid the catch of the helmet shell body 1 and the shield 4 without obstructing the position and the posture change of the jaw 2, which is the most obvious difference between the technical scheme of the invention and the technical scheme proposed by the Chinese patent application CN 105901820A. It should be noted that, when the rotary gear 6 and the rotary post 7 both have the spline-shaped structures 67 (i.e., the bus bar of the spline-shaped structures 67 is parallel to the follower axis O1, as shown in fig. 4), the displacement motion of the rotary gear 6 relative to the fork 2a can only be performed along the axial direction of the follower axis O1, but the rotary gear 6 and the fork 2a and the rotary post 7 both have the same rotational motion about the follower axis O1 (or have the same angular velocity about the follower axis O1), and when the rotary gear 6 and the rotary post 7 both have the spline-shaped structures 67 other than the spline-shaped structures, such as the diagonal structures, i.e., the bus bar of the spline-shaped structures 67 is not parallel to the follower axis O1 (not shown in the figure), the displacement motion of the rotary gear 6 relative to the fork 2a is a combined motion performed simultaneously along the axial direction of the follower axis O1 and the rotational direction about the follower axis O1, and the spline-shaped structures 6 and the spline-shaped structures 67 are the optimal spline-shaped structures (i.e., the spline-shaped structures 67 are shown in fig. 4) from the viewpoint of being advantageous to be manufactured; the invention is fastened or integrally structured with a force-bearing disk 9 at the end part of the rotary column 7, and there is an energy storage spring 10 between the force-bearing disk 9 and the rotary gear 6 on the same side of the helmet shell body 1 (see fig. 4 and as shown in fig. 8 and 11), one end of the energy storage spring 10 is abutted against the force-bearing disk 9, and the other end is abutted against the body of the rotary gear 6 (so that it is not difficult to find that the energy storage spring 10 can move along with the rotary gear 6 and the force-bearing disk 9), meanwhile, a track groove 11 is formed on the bottom bracket 3 or/and the helmet shell body 1, the track groove 11 comprises a first pit 11a and a first slope 11b, wherein the layout characteristic of the first pit 11a is that the first pit 11a is closer to the symmetrical plane P of the helmet shell body 1 than the main track plane 11c of the track groove 11, the first slope 11b is the connecting structure of the main track plane 11c and the first pit 11a (see fig. 4, fig. 8 and 11), the track groove 11 is abutted against the track groove 11 and moves along the axis O along with the track groove 1, and the track groove 11 moves along the axis O along with the track groove; it should be emphasized that the bearing disc 9 of the present invention may be a structure on the rotating post 7, such as a column head or a flanging or a ring groove (not shown), in particular, the bearing disc 9 may be a separate part fastened to the rotating post 7 (see fig. 4, 8 and 11), and the bearing disc 9 is made into a disc-shaped part more advantageously to increase the contact surface between the bearing disc 9 and the track groove 11 so as to improve the stability of the jaw 2 in the changing position and posture, and facilitate assembling the energy storage spring 10 and receiving the elastic force of the energy storage spring 10; it should be noted that, the purpose of the present invention to provide the energy storage spring 10 is: on the one hand, the force which can promote the fork handle 2a to approach to the symmetrical plane P of the helmet shell body 1 is generated by the force, and on the other hand, the gap between relevant parts of the jaw 2 when the position and the posture are changed is effectively eliminated by utilizing the extrusion effect generated by the elastic force of the jaw so as to be beneficial to improving the stability of movement. The energy storage spring 10 is preferably pre-compressed or pre-tensioned to a certain extent when it is mounted on the helmet, and the energy storage spring 10 may have various forms, and in particular the energy storage spring 10 may be a conical spring (as shown in fig. 4, 8 and 11), which is one of the preferred structural arrangements of the energy storage spring 10, because the conical spring may have a smaller axial dimension when it is compressed, thereby facilitating the reduction of the size of the helmet. During the process of lifting the jaw 2 out of its full-helmet configuration, the force-bearing plate 9 has a movement of disengaging from the first pit 11a and a contact movement with the first slope 11b of the track groove 11, and the contact movement causes the force-bearing plate 9 to overcome the spring force of the energy-storage spring 10 and eventually force the fork 2a of the jaw 2 via the rotating post 7 to perform an opening displacement movement away from the symmetry plane P of the helmet shell body 1, which is due to: the contact motion of the bearing disc 9 and the first slope 11b is a climbing action in the process stage of lifting the jaw 2 and separating from the full helmet structure position, and the bearing disc 9 is propped by the first slope 11b to make a displacement motion far away from the symmetry plane P of the helmet shell body 1. In the process of returning to the fully helmet structure position, the support plate 9 keeps contacting with the first slope 11b under the action of the elastic force of the energy storage spring 10 and slides to the first pit 11a along the first slope 11b, and meanwhile, the support plate 9 promotes the fork handle 2a of the support plate 2 to perform folding displacement action close to the symmetrical plane P of the helmet shell body 1 through the rotating column 7 under the compression of the energy storage spring 10. Here, the above-mentioned "opening displacement motion of the fork 2a away from the symmetry plane P of the helmet shell body 1" and "opening displacement motion and closing displacement motion of the fork 2a close to the symmetry plane P of the helmet shell body 1" may be collectively referred to as "opening displacement motion" which reflects the motion behavior of the fork 2a separated on both sides of the helmet shell body 1 to open and close with respect to the symmetry plane P of the helmet shell body 1, which is the most important feature of the helmet of the present invention as distinguished from the existing variable jaw protection type helmet. The above-mentioned "the progress stage of the clapping jaw 2 in the process of being lifted out of its full helmet structure" means: the stage period from the lifting of the chin guard 2 from the full helmet structure position until the fork 2a of the chin guard 2 completes the opening displacement required for avoiding and crossing the outer surface of the helmet shell body 1 and the whole of the shield 4 to advance to the half helmet structure position, and the "stage of progress of the back seating of the chin guard 2 at the full helmet structure position" means: the jaw 2 is in its seated position in the helmet structure in which the jaw 2 of the helmet is in a position fully covering the wearer's chin and mouth and thus has the best safety protection (as shown in fig. 1 to 3), the semi-helmet structure in which the jaw 2 of the helmet is in a position in which it is open without covering the eyes, nose and mouth of the wearer, and in particular in a position in which the jaw 2 is in contact with the rear upper surface of the helmet shell body 1 after the shield 4 is overturned (as shown in fig. 13 to 16), the jaw 2 in the semi-helmet structure not interfering with the wearer's drinking, conversation, telephone and ventilation, etc., and thus being well suited for a rest position when the wearer is at low speed or in a low-driving condition. It should be noted that even though the chin bar 2 is in the semi-helmet configuration, the shield 4 may be fully snapped down (as shown in fig. 13-15) and fully up (as shown in fig. 16). It is obvious that the present invention is to arrange the stationary gear 5 and the rotary gear 6, and arrange the rotary post 7 capable of performing the telescopic displacement action with respect to the rotary gear 6, and to provide the track groove 11 comprising the first slope 11b on the base 3 and/or the helmet shell body 1, on the one hand, the position and posture change when the chin 2 rotates is achieved by utilizing the meshing of the key structure 67 provided on the rotary gear 6 and the rotary post 7 and combining the gear engagement of the stationary gear 5 and the rotary gear 6, thereby achieving the structure variability of the chin 2, and on the other hand, the telescopic displacement action of the rotary post 7 generated by the constraint of the first slope 11b on the force-bearing disc 9 and combining the action of the energy storage spring 10 in the track groove 11 is achieved, thereby being beneficial to improving the capability of the chin 2 to cross the helmet shell body 1 and the shield 4 and other various obstacles. The change in state of the jaw 2 of the present invention during its transition position and posture is described below with reference to fig. 17: fig. 17 (a) shows the jaw 2 in the full helmet configuration position, in which the fork 2a is in a state of being received against the helmet shell body 1, that is, in which the fork 2a is in a closest folded state with respect to the symmetry plane P of the helmet shell body 1, and the strain relief disc 9 is fully seated in the first pit 11a (as shown in fig. 8); fig. 17 (b) shows an initial stage when the helmet wearer lifts the jaw 2 by hand, and the shield 4 is lifted up to the vicinity of the dome of the helmet shell body 1, and the force-bearing disk 9 begins to climb along the first slope 11b of the track groove 11, and the fork 2a generates an opening displacement motion gradually away from the symmetry plane P of the helmet shell body 1 along with the climbing action, which is specifically shown by that during this period the amplitude delta of the opening of the fork 2a compared with the position of the fork in the helmet structure state is gradually increased, and during this period, the greater the extent to which the energy-storage spring 10 deviates from its equilibrium state (i.e. free state) is accompanied by an increasing amplitude delta, in other words the elasticity of the energy-storage spring 10 is also increased; fig. 17 (c) reflects the situation in which the jaw 2 starts to climb over the shield 4 in the fully opened state, when the force-bearing disk 9 has climbed over the first ramp 11b and comes into contact with the main track surface 11c of the track groove 11 (as shown in fig. 11), in other words, during which the fork 2a has completed the full-amplitude opening motion, i.e. it is situated furthest from the plane of symmetry P of the helmet shell body 1, or during which the amplitude delta of the opening of the fork 2a has reached a maximum value compared to its position in the helmet structure state (see fig. 11 and 12), whereas during this phase of maximum amplitude delta the invention is able to ensure that the fork 2a can span (or avoid) various obstacles of the outer surface of the helmet shell body 1, in particular including that the shield 4 can be overturned, of course, when the energy storage spring 10 is in its strongest state; fig. 17 (d) reflects that the chin 2 has crossed over the shield 4 in the fully opened state and is riding over the dome of the helmet shell body 1, in correspondence with which the basin 9 continues to remain in contact with the main track surface 11c of the track groove 11 and the fork 2a continues to remain in the maximum opened state (i.e. the amplitude delta remains at a maximum value); fig. 17 (e) reflects the fact that the jaw 2 has reached and is in the full helmet configuration position and the shield 4 is still in the fully opened condition; fig. 17 (f) reflects the jaw 2 in the full helmet configuration position and the shield 4 in the fully snapped-down position, which is, of course, accomplished by the wearer manually. It should be noted that the above procedure, in turn, is a return transition of the jaw 2 from the semi-helmet configuration to the full-helmet configuration, in which the basic principle according to which the fork handle 2a exhibits a stretching and closing movement is similar and will not be described in detail. In summary, since the fork handle 2a of the jaw 2 can be folded when the full helmet is in the structural position, the technical scheme of the invention can reduce the air flow whistle and reduce the volume, thereby improving the comfort and the storability of the helmet; meanwhile, the folding fork handle 2a can also directly transmit the impact force born by the jaw 2 to the helmet shell body 1, so that the technical scheme of the invention can also improve the stress characteristic, thereby improving the safety and the firmness of the helmet.

Further, the layout of the follower axis O1 in the present invention may take various forms, including a perpendicular or oblique situation between the follower axis O1 and the symmetry plane P of the helmet shell body 1. In particular, the rotation posts 7 of the present invention disposed on both sides of the helmet shell body 1 are coaxially disposed (i.e., they are collinear) along their follower axes O1, and the coaxially disposed follower axes O1 are disposed in a vertical arrangement with respect to the symmetry plane P of the helmet shell body 1 (see fig. 4 and fig. 3, 8, 9, 11 and 15), which has the advantage of avoiding as much as possible the occurrence of movement interference of the fork handles 2a disposed on both sides of the helmet shell body 1 due to the step inconsistency when the positions and postures of the chin pieces 2 are changed, and in particular, ensuring the best movement coordination and consistency of both the fork handles 2a disposed on both sides of the helmet shell body 1. Still further, the shoe 3 and/or the helmet shell body 1 of the present invention may be provided with a latch 12 (as shown in fig. 4, 8 and 11), and the layout principle of the latch 12 is: when the jaw 2 is in the full helmet structure position and is viewed along the direction of the follow-up axis O1 toward the symmetry plane P of the helmet shell body 1, the tongue 12 is located farther from the symmetry plane P of the helmet shell body 1 than the bearing plate 9 (see fig. 8), and the projections of the tongue 12 and the bearing plate 9 when orthographically projecting toward the symmetry plane P of the helmet shell body 1 are intersected, which means that the layout position of the tongue 12 should be set in correspondence with the position of the first pit 11a (see fig. 4, 8 and 11). The purpose of the catch 12 is to prevent uncontrolled opening of the fork handle 2a in the full-helmet configuration position due to accidental impact or unintentional manipulation, since the catch 12 is provided to increase the reliability and safety of the helmet in use if the jaw 2 is in the full-helmet configuration position if it is subjected to accidental impact or if the fork handle 2a tends to be accidentally stretched out due to an artificial incorrect manipulation, the catch 12 is thus engaged by the catch 9, and the catch 12 is then restrained, and the catch 9 is pulled by the rotation post 7 and restrains the further stretching of the fork handle 2a, which is advantageous for increasing the firmness of the jaw 2 in the full-helmet configuration.

In order to enable the fork handle 2a of the jaw 2 to have a storage effect attached to the helmet shell body 1 when the jaw 2 is in the semi-helmet structure position (see fig. 15), so that good pneumatic performance of the helmet can be realized when the jaw 2 is in the semi-helmet structure position, a second sinking pit 11d and a second slope 11e (shown in fig. 4, 8 and 11) can be arranged or included on the track groove 11, the jaw 2 is in a process stage of turning over and separating from the semi-helmet structure position, the force-bearing disk 9 has a action of separating from the second sinking pit 11d, and is contacted with the second slope 11e of the track groove 11, at the moment, the force-bearing disk 9 is climbing along the second slope 11e, during which the amplitude delta of the fork handle 2a expanding in comparison with the position of the jaw in the semi-helmet structure position is gradually increased, and the amplitude delta is larger along with the continuous increase of the amplitude delta, the energy-storage spring 10 is also deviating from the equilibrium state, the energy-bearing disk 10 is also driven to move away from the track groove 11, and the symmetrical surface of the second slope 11c of the jaw 11 is driven by the force-bearing disk 9, and the force-bearing disk 9 is driven to move away from the track 11P (the symmetrical surface 11c of the track 11 is driven by the force-bearing disk 11) and the force-bearing disk is driven to move away from the track 11P 11 along the second slope 11 b) when the track groove 11b is opposite to the second slope 11b (as shown in fig. 4, the symmetrical surface 11c is compared with the track 11b and the position 11b is driven; also, in the stage of the procedure of approaching the jaw 2 to the semi-helmet structure, the force-bearing plate 9 keeps contacting with the second slope 11e under the action of the spring force of the energy-storage spring 10 and slides along the second slope 11e to the second pit 11d (the force-bearing plate 9 is descending along the second slope 11 e), meanwhile, the force-bearing plate 9 pushes the fork handle 2a of the jaw 2 to perform the closing displacement action close to the symmetrical plane of the helmet shell body 1 through the rotating post 7 under the compression of the energy-storage spring 10, and in the process, the opening amplitude delta of the fork handle 2a is gradually reduced, namely, the fork handle 2a is closer to the helmet shell body 1 (not shown in the figure), and obviously, when the jaw 2 reaches the semi-helmet structure, the fork handle 2a of the jaw has good hiding effect, so that the helmet has better aerodynamic performance (see fig. 15). It should be noted that, when the symmetry plane P of the helmet shell body 1 is taken as the observation reference, the gradient direction of the second slope 11e is opposite to that of the first slope 11b described above, as will be apparent from fig. 4, 8 and 11. In addition, it should be noted that, in order to make the jaw 2 have good reliability in the semi-helmet structure position, so as to prevent the fork handle 2a from being accidentally stretched out due to accidental impact or improper manual operation, the present invention may also provide the clamping tongue 12 (as shown in fig. 4, 8 and 11) at or near the position corresponding to the second recess 11d on the collet 3 and/or the helmet shell body 1, and the layout principle thereof will not be repeated herein as described above.

In order to achieve better design of appearance and to improve wearing comfort, the invention can design the variable turning angle of the jaw 2 to 180 degrees, namely the angle through which the fork handle 2a of the jaw 2 rotates relative to the helmet shell body 1 is 180 degrees when the jaw 2 turns from the full helmet structure position to the half helmet structure position, whereas the angle through which the fork handle 2a of the jaw 2 rotates relative to the helmet shell body 1 is 180 degrees when the jaw 2 returns from the half helmet structure position to the full helmet structure position, under the layout design, the center of gravity of the jaw 2 can be better positioned above or close to the neck of a wearer when the jaw 2 of the helmet is positioned at the half helmet structure position, so that even if the helmet is converted into the half helmet structure position, the fatigue of a driver can be relieved, in other words, the design concept of the jaw 2 fork handle 2a of the helmet can indirectly improve safety. Further, in order to better coordinate the layout design of the fork handle 2a in the full helmet structure position and the half helmet structure position, so as to meet the requirement of the appearance modeling of the helmet, and in particular in order to better consider the pneumatic appearance of the jaw 2 against the helmet shell body 1 when the two positions are simultaneously considered, the invention proposes the following design principle aiming at the layout of the tail outer contour line m of the fork handle 2a of the jaw 2: referring to fig. 18, a design line L for the outer contour line m obtained by orthographic projection of the fork handle 2a on the symmetry plane P of the helmet shell body 1 is provided, the design line L can be manually and autonomously selected by a designer according to the overall appearance modeling requirement of the helmet, the design line L can be a free straight line or a limiting reference line, but the design line L needs to be satisfied, and is laid on the symmetry plane P through a layout principle of an motionless point P0 on the orthographic projection of the chin 2, meanwhile, an orthogonal line T passing through the motionless point P0 and perpendicularly intersecting with the design line L is provided on the symmetry plane P, wherein the motionless point P0 is a midpoint of a connecting line of two intersecting points on the symmetry plane P by a designer in the whole helmet structure position and the semi-helmet structure position, namely an intersection point O11 of the motionless axis O1 with the symmetry plane P and a connecting line O12 on the whole helmet structure position in the whole helmet structure position, and the intersection line T2 between the two intersecting points on the symmetry plane P1 and the two perpendicular to the symmetry plane T2 are respectively, and the intersection line T1 is a projection of the motionless point O1 and the contour line T on the two intersecting points on the symmetry plane P1 and the two perpendicular to the symmetry plane T; since the follower axis O1 is optimally arranged perpendicular to the plane of symmetry P, in this case, for convenience of description, the present invention may designate the intersection O11 of the follower axis O1 and the plane of symmetry P as O1 (O11) when the chin guard 2 is in the full-helmet configuration position, as shown in fig. 5 to 7 and 18, and the intersection O12 of the follower axis O1 and the plane of symmetry P may also be designated as O1 (O12) when the chin guard 2 is in the half-helmet configuration position, as shown in fig. 6; it should be noted that, there are various schemes for the outer contour line m of the tail body of the fork 2a capable of satisfying the above design principle, two preferred embodiments are respectively an ellipse (an ellipse-like shape including various non-strict elliptic curves) and a diamond (a diamond-like shape including various non-strict four-straight-line diamonds), including the outer contour line m being a part of the ellipse and the diamond, or the outer contour line m may be formed by a plurality of line segments without limiting it to be a complete ellipse or diamond, in the case of fig. 18, the tail outer contour line m of the fork 2a is designed to be a diamond-like shape, and the design line L in fig. 18 is designed to pass through the intersection point O11 and the intersection point O12; as mentioned above, in addition to this layout design, the tail outer contour m of the fork handle 2a may take other configurations, and the design line L may alternatively not pass through the intersection O11 or/and the intersection O12. The invention adopts the layout design principle of the tail outer contour line m of the fork handle 2a, and the advantages obtained by the method are that: the folding and shrinking effects can be achieved, because enough sinking grooves capable of avoiding the fork handles 2a of the jaw 2 must be reserved on the helmet shell body 1, so that the fork handles 2a can be sunk and shrunk onto the helmet shell body 1 when the jaw 2 is turned from the full helmet structure position to the half helmet structure position, and when the fork handles 2a adopt a scheme of 180 degrees relative to the helmet shell body 1 when the angle of rotation is adopted by the helmet shell body 1, the sinking grooves can meet the folding and shrinking requirements when the fork handles 2a are in the full helmet structure and the half helmet structure as far as possible, and at the moment, no matter the fork handles 2a are positioned at the full helmet structure position or the half helmet structure position, the fork handles 2a can be closely or small gaps are even seamlessly attached to the helmet shell body 1, so that the appearance modeling of the helmet is not only facilitated, but also the pneumatic performance of the helmet is improved.

In order to more reliably improve the reliability of the fork handle 2a during folding, the bearing disc 9 and/or the connecting accessories of the bearing disc 9 can be made of magnetic materials or can be made of magnets, and magnets or magnetic parts (not shown in the figure) are arranged on the helmet shell body 1 or the bottom support 3 at positions corresponding to the first sinking pit 11a and the second sinking pit 11 d. Wherein the attachment of the load bearing disc 9 comprises various parts attached to the load bearing disc 9 and also fasteners such as screws and shims etc. for attaching the load bearing disc 9 to the fork handle 2 a. The advantage of arranging the magnets and using magnetically attractable materials is that the driving force of the energy storage spring 10 can be compensated, because the magnetic attraction is characterized in that the magnetic force generated by the two acting magnets is stronger as the two acting magnets are closer to the two acting magnets, and the acting characteristic of the spring is that the smaller the spring body deviates from the free state (also called the free length), the weaker the acting force generated by the spring body is, and conversely, the stronger the acting force is, so long as the mechanical characteristics of the two acting magnets are fully utilized to arrange them to generate the opening and closing displacement action for driving the fork handle 2a, for example, the magnetic acting body which is mainly used for attracting force is arranged at the stretching end of the spring which is mainly used for compressing the acting force can be utilized for compensating the gradually weakened spring force by the gradually strengthened magnetic attraction, so that the stability and the firmness of the jaw protection 2 can be beneficial.

The shield 4 of the present invention comprises two supporting sides 4a (see fig. 4), wherein the two supporting sides 4a are separated by a symmetry plane P and are separated at two sides of the helmet shell body 1; wherein at least one bottom support 3 comprises an outer cover 3a and a bottom cover 3b, a driving gear 13 capable of rotating in a fixed shaft, a rack 14 meshed with the driving gear 13 and a power spring 15 capable of driving the driving gear 13 to rotate are assembled on the bottom support 3 or the helmet shell body 1 (as shown in fig. 4 and 19), the rack 14 is connected with a supporting side edge 4a of a shield 4, an arc-shaped outer guide groove 16a is formed on the outer cover 3a or/and the helmet shell body 1, an arc-shaped inner guide groove 16b is formed on the bottom cover 3b or/and the helmet shell body 1, the outer guide groove 16a and the inner guide groove 16b are combined together to form a pair of constraint guide rails, and the position and the posture of the rack 14 are constrained by the constraint guide rails, so that the position and the posture of the shield 4 are controlled through the rack 14; in fig. 4, there is shown an example in which an outer guide groove 16a is formed in the outer cover 3a of the shoe 3, at least a part of the outer guide groove 16a has a through groove shape, and an inner guide groove 16b is formed in the bottom cover 3b of the shoe 3, wherein the rack 14 is slidably provided in a restraining 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 a screw) formed on the rack 14 and passing through the through groove in the guide groove 16a and combined with a holding block 4 d; in particular, the present invention also includes a case where the inner guide groove 16b and the outer guide groove 16a and the restraining guide rail formed by them each take a circular arc-shaped structure restraining form, in other words, the opening or hooking movement of the shield 4 is restrained by their restraint so as to take a form of fixed axis rotation or fixed axis swing, and the restraining structure of the shield 4 in the present invention eliminates the swing link compared with the conventional swing link restraining form, so that the space occupied by the restraining structure is less, thereby providing a more flexible condition for the layout design of the shield 4. Here, one of the points of force of the power spring 15 acts on the driving gear 13 (as shown in fig. 19), and the other point of force of the power spring 15 may be located on the base 3 or on the helmet shell body 1 (not shown in the drawings), wherein the trend of the force exerted by the power spring 15 always forces the shield 4 to be lifted, which is, of course, transmitted via the engagement of the driving gear 13 with the rack 14. It should be noted that the power spring 15 of the present invention may be of a tension type or a compression type, and particularly may be of a torsion type, wherein the torsion type is a preferred type because the torsion type can be reasonably arranged by effectively utilizing the body space of the driving gear 13. It should be noted in particular that the shield 4 of the present invention may employ such a preferred design layout strategy: when the jaw 2 is in the position of the full helmet structure, the lower edge 4b of the shield 4 may be fastened to the jaw 2, and the upper edge 4c of the shield 4 may be fastened to the helmet shell body 1 (as shown in fig. 1 to 3); when the shield 4 is in the fully opened position, the jaw 2 can make the crossing action of the shield 4 to complete the state transition between the full helmet structure position and the half helmet structure position.

Further, in order to ensure that the shield 4 is securely held in the snapped-down position (i.e. the shield 4 is positioned directly in front of the helmet in a position that shields the eyes and nose of the wearer from the wind, see fig. 1 to 3), the present invention may provide on the base 3 or/and the helmet shell body 1a locking mechanism comprising an outer tooth 14a provided on the rack 14, an inner tooth 14b fitted on the base 3 or the helmet shell body 1 and a locking tooth spring 14c (see fig. 4 and 19), the body of the inner tooth 14b being constrained by the base 3 or/and the helmet shell body 1 and such that the movement of the inner tooth 14b is in the form of a linear displacement, or a swinging displacement, or a compound displacement comprising a linear displacement and a swinging displacement, wherein the locking tooth spring 14c always forces the inner tooth 14b against the outer tooth 14a. It should be noted that, in the present invention, the tooth structures of the inner teeth 14b and the outer teeth 14a may be in a compatible engagement manner including a pair of two or two-to-two, that is, a single tooth-protruding inner tooth 14b is matched with two tooth-protruding outer teeth 14a (as shown in fig. 4 and 19), or a single tooth-protruding outer tooth 14a is matched with two tooth-protruding inner teeth 14b (not shown), a pair of two tooth-protruding inner teeth 14b is matched with two tooth-protruding outer teeth 14a (not shown), or two tooth-protruding outer teeth 14a are matched with two tooth-protruding inner teeth 14b (not shown); in the situation shown in fig. 19 (a), the shield 4 is locked by the locking mechanism in the fully-snapped-down position, i.e., the lower edge 4b of the shield 4 is in contact with the jaw 2 (when the inner latch 14b is engaged with the outer latch 14 a), and the shield 4 is in a state most suitable for use in riding; in the case shown in fig. 19 (b), the shield 4 is locked in the slightly opened position by the locking mechanism, that is, the lower edge 4b of the shield 4 is separated from the jaw 2 (but the inner latch 14b and the outer latch 14a are also engaged), and the shield 4 can be in a slightly opened state to allow the outside air to be blown into the helmet to remove the mist formed on the shield 4 due to breathing, so that the safety driving is facilitated; in the situation shown in fig. 19 (c), the cover 4 has been unlocked and has been lifted to the fully opened position (in which the inner and outer teeth 14b and 14a have been completely disengaged) by the power spring 15, and this cover 4 is in a state most suitable for use by the rider at rest; the tooth spring 14c can be in the form of a tension or pressure or torsion spring, with the pressure spring being preferably arranged; in the present invention, when the inner latch 14b is locked by the outer latch 14a, the cover 4 is kept at a certain current position, as shown in fig. 19 (a) and 19 (b), and when the inner latch 14b is unlocked by disengaging from the outer latch 14a, the cover 4 can be lifted by the power spring 15, as shown in fig. 19 (c). Still further, an unlocking mechanism is configured on the base 3 and/or the helmet shell body 1, the unlocking mechanism comprises a pressing tongue 17 and a retaining spring 18, see fig. 4 and 19 (a), wherein the pressing tongue 17 comprises an inclined pushing surface 17a, the pressing tongue 17 is arranged between a first pit 11a and a second pit 11d, when the chin 2 advances from a half helmet structure position to a full structure position, the force-bearing disc 9 can contact the inclined pushing surface 17a of the pressing tongue 17, and the pressing tongue 17 can be forced to make a yielding action against the elastic force of the retaining spring 18, and the pressing tongue 17 can drive the inner latch 14b to be separated from the outer latch 14a to unlock the latch mechanism through the yielding action; referring to fig. 4 and 19, the tongue 17 can press the chute 14c of the inner latch 14b by the force-transmitting pin 17b provided thereon, and thereby the pressing action drives the inner latch 14b to disengage from the outer latch 14a, and other structures and transmission methods can be adopted to achieve this function.

In order to prevent the shield 4 from being accidentally lifted up due to collision or unintentional touching in the state that the shield 4 is completely buckled on the jaw 2, particularly, a locking and unlocking mechanism for the shield 4 can be arranged at the lower edge part 4b of the shield 4 and on the body of the jaw 2, thereby improving the reliability and safety of the helmet in use. The locking and unlocking mechanism comprises an inner buckling structure arranged at the position of the lower edge 4b of the protective cover 4 and an outer buckling structure arranged on the body of the jaw 2, wherein the inner buckling structure and the outer buckling structure are mutually corresponding; wherein the inner buckle structure comprises a buckle structure 4d, and the outer buckle structure comprises a bougie 19 which can be forced to be abducted, and a locking hook 19a arranged on the bougie 19 (as shown in fig. 20); in addition, the locking and unlocking mechanism of the invention further comprises a first unlocking key 20 or/and a second unlocking key 21, wherein the first unlocking key 20 and the second unlocking key 21 are both arranged on the body of the jaw guard 2 and can be used as an actuating piece of the unlocking shield 4, the first unlocking key 20 is arranged adjacent to the bougie 19 and can touch the bougie 19 during the actuation, the second unlocking key 21 can unlock the jaw guard 2 in the full helmet structure position and can be controlled to the bougie 19 during the actuation, and when the first unlocking key 20 or/and the second unlocking key 21 touch the bougie 19, the first unlocking key 20 or/and the second unlocking key 21 can cause the bougie 19 to make a yielding action through pressing or pulling; the best layout strategy of the first trip key 20 and the second trip key 21 in the invention is that the structures of the first trip key 20 and the second trip key have intersection with the symmetrical plane P of the helmet shell body 1, or the structures of the first trip key and the second trip key have intersection with the intersection line S; here, the present invention may use a manual action to enable the first trip key 20 and the second trip key 21 to return to the original positions after they complete the actuation task, in particular, the present invention may also use a spring force form to enable the first trip key 20 and the second trip key 21 to return to the original positions automatically after their actuation task is completed, for which a first return spring 22 may be provided to assist the first trip key 20 in resetting (as shown in fig. 21), and a second return spring may be provided to assist the second trip key 21 in resetting (not shown in the figure); in the present invention, when the jaw 2 is in the full helmet structure position and the shield 4 is in the full snap-fit position on the jaw 2, the locking and unlocking mechanism of the shield 4 can have three working conditions: a) When both the first unlocking key 20 and the second unlocking key 21 are not activated, the lock hook 19a on the bougie 19 is at the original position, and the lock hook 19a at the original position can be hooked to the buckle structure 4d of the inner buckle structure and can be locked to the lock protection cover 4 according to the original position as shown in fig. 21 (a); b) During actuation of the first trip key 20, the first trip key 20 is able to touch the bougie 19 and by this touching action can cause the lock catch 19a of the bougie 19 to disengage from its original position, whereupon the trip shield 4 is shown in fig. 21 (b), the first return spring 22 described herein can assist the first trip key 20 to return to its original position or allow the first trip key 20 to remain in place normally; c) During actuation of the second trip key 21, this second trip key 21 is capable of actuating the bougie 19 and, by virtue of this actuation action, of causing the lock catch 19a of the bougie 19 to disengage from its original position, whereupon the trip shield 4 is shown in fig. 21 (c), a second return spring as described herein may assist in restoring the second trip key 21 to its original position or may allow the second trip key 21 to remain in place in its normal state. In the situation shown in fig. 21 (c), the second trip key 21 is manually pulled to generate an off-site action, and drives the bougie 19 through a middleware drag hook 23 to cause the bougie 19 to generate an off-site yielding action, but the first trip key 20 can still be kept in the original position without being pressed. The second trip key 21 of the present invention is implemented in a manner of swinging displacement around the rotation shaft 21a, wherein the rotation shaft 21a is constrained by the seat hole 24a on the base plate 24, the seat hole 24a can be a complete round hole structure (not shown in the figure) or a partial round hole structure (as shown in fig. 20), the base plate 24 is fastened on the body of the jaw 2 or the base plate 24 and the body of the jaw 2 are integrally formed, in the embodiment shown in fig. 20 and 21, the draw hook 23 drives the bougie 19 through a draw hole 19c on the body of the bougie 19, and the best structural form of the draw hole 19c is a waist hole structure because the structure can form a larger redundant space so as to avoid interference more effectively; the bougie 19 can realize the yielding displacement action by adopting the swing of the rotary pin 19b around the body of the bougie, and the rotary pin 19b is rotatably assembled on the base 25, wherein the base 25 is fastened on the body of the jaw guard 2 or is integrally formed on the body of the jaw guard; it should be noted that, in order to allow the bougie 19 to return reliably to its original position even when it is not acted upon by the first trip key 20 and/or the second trip key 21, the present invention may further provide a third return spring 26 (as shown in fig. 20 and 21), one end of the third return spring 26 abutting against the bougie 19, and the other end thereof abutting directly or indirectly against the body of the jaw 2; it should be noted that, the actuation actions performed by the first trip key 20 and the actuation actions performed by the second trip key 21 may be either actions performed alone or actions performed in combination, that is, the yielding actions performed by the bougie 19 do not interfere with each other; it should be further noted that the first trip key 20 may be directly driven (as shown in fig. 21) or indirectly driven (i.e. driven by other parts or mechanisms (not shown); in addition, the lock hook 19a may have various shapes, for example, a wedge-shaped structure (as shown in fig. 21) may be adopted, a clamping edge or a lug (not shown in the figure) may be adopted, and in order to ensure the positioning consistency of the lock hook 19a, a positioning clamping edge 2b (see fig. 21) may be further arranged on the body of the jaw guard 2, and the positioning clamping edge 2b may be used to effectively ensure that the lock hook 19a is in a correct position during assembly. The first trip key 20 of the present invention can be arranged at the upper lip of the jaw guard 2, and the advantage of this arrangement is that when the shield 4 is in a fully engaged position with the jaw guard 2, the first trip key 20 is located just adjacent to the inner engagement structure of the shield 4, and when it is required to remove mist from the helmet by using fresh air from the outside of the helmet, the first trip key 20 can be manually pressed to trigger the bougie 19 to unlock the shield 4, and at the same time, the finger can be used to push the shield 4 to force it to generate slight opening displacement, so that a ventilation gap 27 is formed between the lower edge 4b of the shield 4 and the jaw guard 2 as shown in fig. 19 (b), thereby improving safety when the helmet is worn.

Compared with the prior art, the helmet shell has the outstanding advantages that the static gear 5 and the rotary gear 6 are arranged on the helmet shell body 1, meanwhile, the rotary column 7 capable of performing telescopic displacement action relative to the rotary gear 6 is arranged on the fork handle 2a of the jaw 2, and the track groove 11 comprising the first sunken pit 11a and the first slope 11b is arranged on the bottom support 3 or/and the helmet shell body 1, so that on one hand, the jaw 2 is restrained and achieves rotary position and posture change by meshing the static gear 5 and the gear of the rotary gear 6 by utilizing the key structure 67 arranged on the rotary gear 6 and the rotary column 7, on the other hand, the jaw 2 is restrained and achieves displacement action of opening and closing relative to the symmetrical surface P of the helmet shell body 1 by utilizing the first slope 11b of the track groove 11 and combining the telescopic action of the rotary column 7, in other words, the fork handle body of the jaw 2 can be enabled to have displacement action far from the symmetrical surface P of the helmet shell body 1 in the process of opening and separating from the helmet shell body, and on the other hand, and the jaw 2 is enabled to have symmetrical displacement action close to the fork handle body in the whole position of the helmet shell body in the process of returning to the helmet shell body 1 in the whole structure. Compared with the traditional variable jaw-protecting structure helmet, the fork handle 2a of the variable jaw-protecting helmet can be outwards stretched to avoid the catch of the helmet shell body 1 and the shield 4 when the jaw-protecting structure helmet is turned over so as not to influence the conversion between the full helmet structure position and the half helmet structure position, and on the other hand, the fork handle 2a of the variable jaw-protecting structure helmet can be in a sinking folding structure state relative to the helmet shell body 1 when the jaw-protecting structure 2 is in the full helmet structure position, so that the variable jaw-protecting structure helmet has the following advantages: firstly, under the common driving wearing working condition of a full helmet structure, the jaw-protecting 2 fork handle 2a can be integrated with the helmet shell body 1 to eliminate the protruding fork handle 2a of the traditional variable jaw-protecting structure, so that the airflow whistle caused by the fork handle 2a which is too protruding on the outer surface of the helmet during driving can be effectively eliminated, the wearing comfort of the helmet is improved, the size of the helmet is reduced, and the storability of the helmet is better; secondly, the jaw 2 with the sinking structure layout can directly support the fork handle 2a body on the helmet shell body 1 when the whole helmet structure is positioned, so that the stress of the jaw 2 can be directly transmitted to the helmet shell body 1 when the jaw 2 is impacted and collided, and the safety and the firmness of the helmet in use can be improved greatly.

The above embodiments are merely preferred embodiments of the present invention, and are not intended to limit the scope of the present invention in any way, therefore: all equivalent changes in structure, shape and principle are covered by the protection scope of the invention.

Claims

1. The gear-constrained jaw-protecting type helmet comprises a helmet shell body, a jaw, two holders and a shield, wherein the helmet shell body is provided with a symmetrical surface, the two holders are separated by the symmetrical surface and are separated from the two side surfaces of the helmet shell body, the two holders are fastened on the helmet shell body or are manufactured in an integral structure with the helmet shell body, the jaw is provided with two fork handles, and the two fork handles are separated from the two side surfaces of the helmet shell body; the helmet shell comprises a helmet shell body, wherein the helmet shell body is provided with a rotating gear and a stationary gear, the rotating gear is arranged on two side edges of the helmet shell body, the stationary gear is an internal tooth configuration gear, the stationary gear is in a stationary state relative to the helmet shell body, the rotating gear is an external tooth configuration gear, and the rotating gear can change position relative to the helmet shell body; the method is characterized in that: the helmet shell comprises a helmet shell body, a stationary gear, a rotating gear, a fork handle and a collet which are distributed on the same side of the helmet shell body, wherein the stationary gear, the rotating gear, the fork handle and the collet are jointly participated in forming a constraint mechanism capable of changing the position and the posture of a jaw, the fork handle in the constraint mechanism comprises a columnar rotating column, the rotating column is provided with a follow-up axis which is stationary relative to the fork handle, a key structure is arranged on the rotating column, the axis of the rotating gear is coaxial with the follow-up axis, and the key structure is also arranged on the rotating gear; the stationary gear and the rotary gear which belong to the same constraint mechanism are engaged with each other, and the rotary column and the rotary gear which belong to the same constraint mechanism are engaged with each other through the key structure; a through groove rail is arranged on the bottom support, the rotating column is in a layout form penetrating through the groove rail, the grooved rail comprises a rail edge, and the rail edge and the rotating gear or/and the rotating column have contact behaviors, and the grooved rail can be used for enabling the rotating gear to keep meshed with the static gear; when the jaw is moved by changing the position and the posture, the rotating column moves synchronously along with the fork handle, meanwhile, the rotating gear which is matched and meshed with the rotating column is driven by the rotating column to also start to rotate around the follow-up axis, and the fork handle and the rotating column can also perform telescopic displacement motion along the follow-up axis direction relative to the rotating gear; a bearing disc is fastened or integrally manufactured at the end part of the rotating column, and an energy storage spring is arranged between the bearing disc and the rotating gear at the same side of the helmet shell body; the support or/and helmet shell body is provided with a track groove, the track groove comprises a first pit and a first slope, and the bearing disc is abutted against the track groove and can slide along the track groove; the support plate has a behavior of separating from the first sinking pit and a contact behavior with the first slope of the track groove in the process stage of lifting the support plate from the full helmet structure position, and simultaneously the contact behavior enables the support plate to overcome the elasticity of the energy storage spring and promote the fork handle of the support plate to generate an opening displacement motion far away from the symmetrical plane of the helmet shell body through the rotating column; the support plate keeps contact with the first slope under the action of the elasticity of the energy storage spring and slides to the first sinking pit along the first slope, and simultaneously the support plate promotes the fork handle of the support plate to perform folding displacement action close to the symmetrical plane of the helmet shell body through the rotating column under the compression of the energy storage spring.

2. A gear-constrained variable jaw-guard helmet according to claim 1, wherein: the follow-up axes of the rotating columns which are respectively arranged at the two sides of the helmet shell body are coaxially arranged, and the follow-up axes and the symmetrical surface of the helmet shell body are vertically distributed.

3. A gear-constrained variable jaw-protection helmet according to claim 2, characterized in that: the helmet shell is characterized in that the collet or/and the helmet shell body is provided with a clamping tongue, when the jaw is in a state of being in a whole helmet structure position and is observed towards a symmetry plane of the helmet shell body along the follow-up axis direction, the clamping tongue is located at a position farther from the symmetry plane of the helmet shell body than the force bearing disc, and the clamping tongue and the force bearing disc are projected to be in an intersection state when being projected to the symmetry plane of the helmet shell body.

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

5. A gear-constrained variable jaw-guard helmet according to claim 4, wherein: the key structures of the rotating gear and the rotating column are in straight-line structures, and when the positions and the postures of the jaw guard are changed, the rotating gear and the fork handle have the same rotating angular speed around the follow-up axis.

6. A gear-constrained variable jaw-guard helmet according to claim 5, wherein: the bearing disc has a behavior of separating from the second sinking pit and is contacted with the second slope of the track groove, and meanwhile, the bearing disc can overcome the elasticity of the energy storage spring and promote the fork handle of the jaw to generate an opening displacement action far from the symmetrical plane of the helmet shell body through the rotating column; the support plate keeps contact with the second slope under the action of the elasticity of the energy storage spring and slides to the second sinking pit along the second slope, and simultaneously the support plate promotes the fork handle of the support plate to perform folding displacement action close to the symmetrical plane of the helmet shell body through the rotating column under the compression of the energy storage spring.

7. A gear-constrained variable jaw-guard helmet according to claim 6, wherein: the angle through which the fork handle of the chin bar rotates relative to the helmet shell body is 180 degrees when the chin bar is turned from the full helmet structural position to the half helmet structural position.

8. A gear-constrained variable jaw-guard helmet according to claim 7, wherein: the helmet shell is provided with a design line aiming at an outer contour line obtained by orthographic projection of a fork handle on a symmetrical plane of a helmet shell body, the design line falls on the symmetrical plane and passes through an immobile point on orthographic projection of a jaw guard, and meanwhile, the symmetrical plane is provided with an orthogonal line passing through the immobile point and being perpendicular to the design line, wherein the immobile point is a connecting midpoint of two intersection points of a follow-up axis of a rotating column on the symmetrical plane when the jaw guard is at a full helmet structure position and a half helmet structure position, and in addition, two boundary lines which are made by two intersection points of the follow-up axis of the rotating column on the symmetrical plane when the jaw guard is at the full helmet structure position and the half helmet structure position are respectively arranged, and the two boundary lines fall on the symmetrical plane and are perpendicular to the design line, so that the design principle of the jaw guard fork handles the outer contour line at the tail part of the jaw guard is as follows: the fork handle orthographic projection outline lines positioned between the two boundary lines on the symmetrical plane are symmetrically distributed about the design line and the orthogonal line.

9. A gear-constrained variable jaw-guard helmet according to claim 8, wherein: the bearing disc and/or the connecting accessory of the bearing disc are/is made of magnetic attraction materials or are magnets, and magnets or magnetic attraction parts are arranged on the helmet shell body or the bottom support at positions corresponding to the first sinking pits and the second sinking pits.

10. A gear-constrained variable jaw guard as claimed in any one of claims 1 to 9 wherein: the shield comprises two supporting side edges which are separated by the symmetrical plane and are arranged beside the two sides of the helmet shell body; at least one bottom support comprises an outer cover and a bottom cover, a driving gear capable of rotating by a fixed shaft, a rack meshed with the driving gear and a power spring capable of driving the driving gear to rotate are assembled on the bottom support or the helmet shell body, the rack is connected with the supporting side edge of the protective cover, an arc-shaped outer guide groove is formed in the outer cover or/and the helmet shell body, an arc-shaped inner guide groove is formed in the bottom cover or/and the helmet shell body, and the outer guide groove and the inner guide groove are combined together to form a pair of constraint guide rails, so that the position and the posture of the rack are constrained by the constraint guide rails.

11. The gear-constrained variable jaw guard helmet of claim 10 wherein: the tooth locking mechanism comprises an outer tooth arranged on the rack, an inner tooth assembled on the base or the helmet shell body and a tooth locking spring, wherein the inner tooth locking mechanism is restrained by the base or/and the helmet shell body and enables movement of the inner tooth locking mechanism to be in a linear displacement mode, or in a swinging displacement mode or in a compound displacement mode comprising linear displacement and swinging displacement, and the action trend of the elastic force of the tooth locking spring always forces the inner tooth locking mechanism to abut against the outer tooth locking mechanism.

12. The gear-constrained variable jaw guard helmet of claim 11 wherein: the unlocking mechanism comprises a pressing tongue and a retaining spring, wherein the pressing tongue comprises an inclined pushing surface and is arranged between the first sinking pit and the second sinking pit, when the jaw guard advances from the half helmet structure position to the full structure position, the bearing disc can contact the inclined pushing surface of the pressing tongue and can force the pressing tongue to make a yielding action, and the pressing tongue can drive the inner clamping teeth to be separated from the outer clamping teeth to unlock the locking tooth mechanism.

13. A gear-constrained variable jaw guard as claimed in any one of claims 1 to 9 wherein: the protective cover lock catch and release mechanism is arranged at the lower edge part of the protective cover and on the body of the protective jaw, and comprises an inner buckle structure arranged at the lower edge part of the protective cover and an outer buckle structure arranged on the protective jaw body, wherein the inner buckle structure comprises a buckle structure, and the outer buckle structure comprises a bougie capable of being forced to be bent and a lock hook arranged on the bougie; in addition, the shield lock and unlock mechanism further comprises a first unlock key or/and a second unlock key, wherein the first unlock key and the second unlock key are both arranged on the body of the jaw guard and can be used as an actuating piece of the unlock shield, the first unlock key is arranged adjacent to the bougie and can touch the bougie during the actuation of the first unlock key, and the second unlock key can unlock the jaw guard in the full helmet structure position and can be controlled to the bougie during the actuation of the second unlock key; when the jaw is in the whole helmet structure position and the shield is completely buckled on the jaw, the shield lock catch and the unbuckling mechanism can have three working conditions: a) When the first unbuckling key and the second unbuckling key are not touched, the lock hook on the bougie is positioned at the original position, and the lock hook positioned at the original position can be hooked on the buckle structure of the inner buckle structure and can lock the shield according to the buckle structure; b) When the first unlocking lock is actuated, the first unlocking key can touch the bougie, and the lock hook of the bougie can be driven to be separated from the original position through the touch action, so that the shield is unlocked accordingly; c) The second trip key is capable of driving the bougie during actuation of the second trip key and, by virtue of this driving action, of causing the lock catch of the bougie to disengage from its original position, thereby tripping the shield.