A helmet visor limiting and locking mechanism

Abstract

This utility model discloses a helmet visor limiting and locking mechanism, including a button, a spring, a sleeve, a positioning plate, multiple rolling elements, a bushing, and a cap-shaped nut. The button is located inside the sleeve and protrudes from the outer end of the sleeve. The inner end of the sleeve is connected to the cap-shaped nut, and the outer end is connected to the positioning plate. The spring is located inside the sleeve, with one end contacting the button and the other end contacting the cap-shaped nut. The bushing is fitted onto the outer surface of the sleeve, with its outer end contacting the sleeve and its inner end contacting the cap-shaped nut. The rolling elements are located between the sleeve and the positioning plate. This utility model uses the rolling elements to achieve locking and unlocking, allowing the visor to lock at the required angle to withstand deflection torque without moving.

Description

Technical Field

[0001] This utility model relates to a helmet visor limiting and locking mechanism, belonging to the field of protective helmet technology. Background Technology

[0002] A helmet visor locking mechanism is a mechanical device used to fix the position of the helmet visor, ensuring that the visor remains stably at a preset angle or completely locked when opened or closed, preventing accidental movement. Riot helmet visors can withstand frontal and side impacts, transmitting the impact force to the helmet. Furthermore, when the visor is subjected to a deflection torque, the locking mechanism ensures that the visor does not shift, a feature not found in ordinary civilian helmet visors. Summary of the Invention

[0003] The technical problem to be solved by this utility model is to provide a helmet visor limiting and locking mechanism.

[0004] To achieve the above technical objectives, the present invention adopts the following technical solution:

[0005] A helmet visor limiting and locking mechanism includes a button, a spring, a sleeve, a positioning plate, multiple rolling elements, a bushing, and a cap nut;

[0006] The button is located inside the sleeve and protrudes from the outer end of the sleeve; the inner end of the sleeve is connected to the cap nut, and its outer end is connected to the positioning plate; the spring is located inside the sleeve, with one end in contact with the button and the other end in contact with the cap nut.

[0007] The bushing is fitted onto the outer surface of the sleeve, with its outer end in contact with the sleeve and its inner end in contact with the cap nut; the rolling element is disposed between the sleeve and the positioning plate.

[0008] Preferably, the button includes a button body, a button end, and a button inner hole;

[0009] Both the button body and the button end are column structures with a longitudinal direction, and they are coaxial and connected; the outer diameter of the button body is larger than that of the button end; the inner hole of the button extends from the inner end face of the button body to the outside.

[0010] Preferably, the sleeve includes a sleeve body, a locking ring, and a sleeve cap;

[0011] The sleeve body is a tube structure with a longitudinal direction, and its outer surface is a rounded rectangular structure when projected perpendicular to the longitudinal direction; a sleeve thread is provided along the outer surface of the sleeve body.

[0012] The locking ring is a tube structure with a longitudinal direction. Its inner end face contacts the outer end face of the sleeve body, and its outer end face contacts the inner end face of the sleeve cover. The inner surface of the locking ring is coplanar with the inner surface of the sleeve body, and its outer surface is a cylindrical surface with a diameter larger than the outer diameter of the sleeve body.

[0013] The sleeve cover is a flange structure with an inner hole along its axis; the size of the inner hole of the sleeve cover is smaller than the inner surface size of the locking ring and the sleeve body.

[0014] Preferably, the positioning disk includes a positioning disk body and a positioning disk flange;

[0015] The positioning disk body is a flange structure; the positioning disk flange is a raised structure on the edge of the positioning disk body, which is adapted to the edge of the mask;

[0016] The center of the positioning disc body is provided with a positioning disc inner hole, the structure of which is adapted to the outer surface of the locking ring.

[0017] Preferably, the bushing includes a bushing body, a bushing partition, a bushing slip ring, and a bushing inner hole;

[0018] Both the bushing body and the bushing slip ring are tubular structures with a longitudinal direction; the outer surface of the bushing body, when projected perpendicular to the longitudinal direction, is a rectangular structure with rounded ends; the outer surface of the bushing slip ring is a cylindrical surface; the bushing partition is a plate structure extending along a vertical plane; the inner end face of the bushing partition contacts the outer end face of the bushing body, and its outer end face contacts the inner end face of the bushing slip ring; the bushing body and the bushing slip ring are coaxial.

[0019] The bushing inner hole extends through the bushing body, the bushing partition, and the bushing slip ring along the axial direction; the structure of the bushing inner hole is adapted to the outer surface of the sleeve body.

[0020] Preferably, the cap nut is a nut structure with one end closed, and its thread is adapted to the sleeve thread; the inscribed circle of the cap nut is larger than the inner end face of the bushing body.

[0021] Preferably, the locking ring is provided with a plurality of locking holes in its circumferential direction; the locking holes are arranged along the circumferential direction of the locking ring and penetrate the inner and outer surfaces of the locking ring; the structure of the locking holes is adapted to the rolling element.

[0022] Preferably, a plurality of locking grooves are provided along the circumference of the inner hole of the positioning disk; the locking grooves are arc grooves, and their longitudinal direction extends along the thickness direction of the positioning disk; the arc curvature of each locking groove is the same and is adapted to the outer diameter of the rolling element.

[0023] Preferably, the positioning disc is sleeved on the outer surface of the locking ring; the outer end face of the positioning disc body contacts the inner end face of the sleeve cover; and the rolling element is disposed within the space surrounded by the locking hole, the locking groove, and the button body.

[0024] Compared with the prior art, the helmet visor locking and limiting mechanism provided by this utility model has the following advantages:

[0025] (1) The structure is compact and the safety performance is high. The mask limiting and locking mechanism relies on the radial movement of the rolling body on the outside of the mask and the elastic deformation of the spring to work together. Only the cap nut protrudes from the inside of the helmet. When the helmet is impacted, the safety hazard to the wearer's head is small.

[0026] (2) High positioning accuracy, fast and smooth locking and unlocking. The rolling element is driven by a spring to engage with the locking groove of the positioning plate, forming a mechanical self-lock. After the spring is pressed to overcome the elastic force, the rolling element disengages from the locked position, achieving rapid unlocking.

[0027] (3) High impact resistance and high reliability. When the mask is impacted, the rolling elements transmit the torque to the helmet through line contact or surface contact, which can withstand large continuous torque and impact torque without displacement, while reducing frictional resistance. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the structure of a helmet in the prior art;

[0029] Figure 2 This is a schematic diagram of the structure of a helmet visor limiting and locking mechanism in an embodiment of the present utility model;

[0030] Figure 3 for Figure 2 An explosion diagram of the helmet visor locking mechanism;

[0031] Figure 4 for Figure 2 A cross-sectional schematic diagram of the helmet visor locking mechanism;

[0032] Figure 5 for Figure 4 A schematic diagram of the button structure in the image;

[0033] Figure 6 for Figure 3 A schematic diagram of the sleeve structure in the middle;

[0034] Figure 7 for Figure 6 A cross-sectional view of the sleeve in the middle;

[0035] Figure 8 for Figure 3A schematic diagram of the end face structure of the positioning disk in the diagram;

[0036] Figure 9 for Figure 3 A schematic diagram of the bushing structure;

[0037] Figure 10 for Figure 4 Another schematic diagram of the helmet visor limiting locking mechanism. Detailed Implementation

[0038] The technical content of this utility model will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0039] This utility model embodiment provides a helmet visor limiting and locking mechanism, which uses a pressing spring to achieve a rotating engagement between a rolling element and a groove for limiting and locking. The end of the helmet visor limiting and locking mechanism facing the inside of the helmet (the side opposite the head) is called the inner end (inner side), and the end facing the outside of the helmet (the side opposite the head) is called the outer end (outer side).

[0040] like Figure 1 As shown, the helmet visor limiting and locking mechanism 100 is used to connect the helmet 200 and the visor 300, so that the visor 300 can rotate about the design axis of the helmet 200 and lock at the design angle.

[0041] like Figures 2-4 As shown, the helmet visor limiting and locking mechanism 100 provided in this embodiment of the present invention includes a button 1, a spring 2, a sleeve 3, a positioning plate 4, multiple rolling elements 5, a bushing 6, and a cap-shaped nut 7. Among them, Figure 4 The helmet visor limiting locking mechanism 100 shown is in the locked state.

[0042] like Figure 5 As shown, the button 1 provided in this embodiment of the present invention is an integrally formed structure, including a button body 11, a button end 12, a button inner hole 13, and a button shoulder 14. Both the button body 11 and the button end 12 are cylindrical structures with a longitudinal direction, and their cross-sectional shapes perpendicular to the longitudinal direction are circular, rectangular, or regular polygonal. The outer end face of the button body 11 and the inner end face of the button end 12 are in contact and connected, and are coaxial. The outer diameter of the button body 11 is larger than that of the button end 12. The button inner hole 13 extends outward from the inner end face of the button body 11, and is coaxial with the button body 11 and the button end 12. The outer end of the button body 11 has a chamfered structure, called the button shoulder 14. Its structure is adapted to the button end 12, forming a progressive structure from the button body 11 to the button end 12. Preferably, the material of the button 1 is metal.

[0043] Spring 2 is a compression spring, and its structure is adapted to the inner hole 13 of the button.

[0044] like Figure 6 and Figure 7 As shown, the sleeve 3 provided in this embodiment of the present invention is an integrally formed structure, including a sleeve body 31, a locking ring 32, and a sleeve cap 33. The sleeve body 31 is a tubular structure with a longitudinal direction, having an outer surface and a hollow inner surface. The projection of the outer surface of the sleeve body 31 perpendicular to the longitudinal direction is a rounded rectangular structure (also called a racetrack shape or oblong structure), that is, it includes a pair of symmetrically arranged arc surfaces 31a and a pair of symmetrically arranged planes 31b. The curvature of each arc surface 31a is the same, and they are coaxial with the sleeve body 31. The sleeve 3 is provided with sleeve threads 34 along the arc surfaces 31a. The inner surface structure of the sleeve body 31 is adapted to the outer surface 11a of the button body 11, for example, both being circular, rectangular, or regular polygonal.

[0045] The locking ring 32 is a tubular structure with a longitudinal direction, extending horizontally. Its inner surface is coplanar with the inner surface of the sleeve body 31. Its outer surface is a cylindrical surface with a diameter larger than the outer diameter of the arc surface 31a of the sleeve body 31. Multiple locking holes 35 are provided along the circumference of the locking ring 32. The locking holes 35 are evenly arranged along the circumference of the locking ring 32 and penetrate both the inner and outer surfaces of the locking ring 32. Their structure is adapted to the rolling element 5. Optionally, the number of locking holes 35 is an integer multiple of the number of rolling elements 5. For example, when the rolling element is a ball, the locking hole 35 is a circular hole structure; when the rolling element is a roller, the locking hole 35 is a rectangular hole or an oblong hole structure.

[0046] The sleeve cover 33 is a flange structure with thickness, extending along a vertical plane. An inner hole 36 is provided along the axis of the sleeve cover 33, the size of which is smaller than the inner surface dimensions of the locking ring 32 and the sleeve body 31. The structure of the inner hole 36 conforms to the outer surface 12a of the button end 12, for example, being circular, rectangular, or a regular polygon.

[0047] The inner end face of the locking ring 32 contacts the outer end face of the sleeve body 31, and its outer end face contacts the inner end face of the sleeve cover 33. The inner surfaces of the sleeve body 31 and the locking ring 32 are coaxial with the inner hole 36 of the sleeve cover. Because the outer diameter of the locking ring 32 is larger than the outer diameter of the arc surface 31a of the sleeve body 31, an outer stop 37 with a boss structure is formed between the inner end face of the locking ring 32 and the sleeve body 31. Because the size of the inner hole 36 of the sleeve cover is smaller than the inner surface size of the locking ring 32, an inner stop 38 with a boss structure is formed between the inner surface of the sleeve cover 33 and the locking ring 32. Preferably, the sleeve 3 is made of metal.

[0048] like Figure 8As shown, the positioning disc 4 provided in this embodiment of the present invention is an integrally formed structure, including a positioning disc body 41 and a positioning disc flange 42. The positioning disc body 41 is a flange structure with thickness, extending along a vertical plane. The positioning disc flange 42 is a raised structure on the edge of the positioning disc body 41, adapted to the edge of the face shield 100 to protect the edge of the face shield 100 from impact. A positioning disc inner hole 43 is provided at the center of the positioning disc body 41; this inner hole is a through hole, and its structure is adapted to the outer surface of the locking ring 32.

[0049] Multiple locking grooves 44 are provided circumferentially along the inner hole 43 of the positioning disk. Each locking groove 44 is an arc groove, extending longitudinally along the thickness direction of the positioning disk 4. The arc curvature of each locking groove 44 is the same, adapting to the outer diameter of the rolling element 5. The center of each locking groove 44 is equidistant from the axis of the positioning disk body 41, and they are evenly distributed. That is, they are evenly distributed circumferentially with the projection of the axis of the positioning disk body 41 as the center. Optionally, the cross-sectional structure of the locking groove 44 can be any shape adapted to the rolling element 5. Optionally, the number of locking grooves 44 is an integer multiple of the number of rolling elements 5. Preferably, the material of the positioning disk 4 is metal.

[0050] The rolling element 5 provided in this embodiment of the invention is a ball bearing structure. Optionally, the rolling element 5 is a roller structure. The structure and dimensions of the rolling element 5 are adapted to the locking hole 35, the locking groove 44, and the button shoulder 14. Preferably, the diameter of the rolling element 5 is greater than the depth of the locking hole 35, that is, greater than the thickness of the locking ring 32.

[0051] like Figure 9 As shown, the bushing 6 provided in this embodiment of the present invention is an integrally formed structure, including a bushing body 61, a bushing partition 62, a bushing slip ring 63, and a bushing inner hole 64. Both the bushing body 61 and the bushing slip ring 63 are tubular structures with a longitudinal direction. The outer surface of the bushing body 61, projected perpendicular to the longitudinal direction, is a rounded rectangular structure, comprising a pair of symmetrically arranged arc surfaces 61a and a pair of symmetrically arranged planes 61b. The curvature of each arc surface 61a is the same, and they are coaxial with the bushing body 61. The outer surface of the bushing slip ring 63 is a cylindrical surface. The bushing partition 62 is a plate structure extending along a vertical plane.

[0052] The inner end face of the bushing partition 62 contacts the outer end face of the bushing body 61, and its outer end face contacts the inner end face of the bushing slip ring 63. The bushing body 61 and the bushing slip ring 63 are coaxial. The bushing inner hole 64 passes through the bushing body 61, the bushing partition 62, and the bushing slip ring 63, and is coaxial with them. The cross-sectional shape of the bushing inner hole 64 perpendicular to its axis is an elongated oval hole structure, which is adapted to the rounded rectangular structure of the outer surface of the sleeve body 31.

[0053] The cap-shaped nut 7 provided in this embodiment of the utility model is a nut structure with one end closed, and its thread is adapted to the sleeve thread 34. The inner circle dimension (outer diameter) of the cap-shaped nut 7 is larger than the inner end face of the bushing body 61.

[0054] like Figure 4 As shown, the positioning disc 4 is connected to the face mask 300, and the rolling element 5 contacts the locking hole 35, the locking groove 44 and the button body 11, so that the face mask 300 is locked and cannot rotate relative to the helmet 200.

[0055] The button 1 is located inside the sleeve 3, with its end 12 passing through the inner hole 36 of the sleeve cover and protruding from the outer end of the sleeve cover 33. The shoulder 14 of the button abuts against the inner stop 38 of the sleeve 3, preventing the button 1 from protruding outwards and falling off. The inner end of the sleeve 3 is connected to the cap nut 7 via the sleeve thread 34. The spring 2 is in a pre-compressed state and is located inside the sleeve 3, between the button 1 and the cap nut 7. One end of the spring is located inside the inner hole 13 of the button and abuts against the button 1, while the other end abuts against the cap nut 7.

[0056] The bushing 6 is fitted onto the outer surface of the sleeve body 31. The outer end face of the bushing 6 abuts against the outer stop 37 of the sleeve 3, and its inner end face abuts against the outer end face of the cap nut 7. The helmet 200 has a rounded rectangular hole structure adapted to the outer surface of the bushing body 61, which is fitted onto the outer surface of the bushing body 61. The face mask 300 has a circular hole structure adapted to the outer surface of the bushing slip ring 63, which is fitted onto the outer surface of the bushing slip ring 63. A bushing partition 62 is disposed between the helmet 200 and the face mask 300 to separate the two and prevent contact friction. Therefore, the bushing body 61 of the bushing 3 transmits torque to the helmet 200 through the rounded rectangular structure and the elongated hole, maintaining a fixed angle, and the bushing slip ring 63 is slidably connected to the face mask 300 through the circular hole.

[0057] The positioning disc 4 is fitted onto the outer surface of the locking ring 32. In other words, the inner surface of the positioning disc's inner hole 43 and the outer surface of the locking ring 32 are parallel to each other and aligned along the axial direction. In the locked state, the locking groove 44 is opposite to the locking hole 35 in the radial direction of the positioning disc 4, and its radial projection covers all or part of the locking hole 35. The inner end face of the positioning disc body 41 is used to contact and connect with the outer surface of the face mask 300, and its outer end face is in contact with the inner end face of the sleeve cover 33. The rolling element 5 is disposed in the space surrounded by the locking hole 35, the locking groove 44, and the button body 11. In the unlocked state, the locking groove 44 is not opposite to the locking hole 35 in the radial direction of the positioning disc 4. The rolling element 5 is disposed in the space surrounded by the locking hole 35, the positioning disc's inner hole 43, and the button end 12.

[0058] The installation steps are as follows: Insert the inner end of the bushing 6 into the helmet 200, and fit the face mask 300 onto its outer end. Connect the positioning plate 4 to the face mask 300. Pass the sleeve 3 through the bushing 6 and install the rolling element 5. Insert the button 1 into the sleeve 3 and install the spring 2. Tighten the cap nut 7 to the inner end of the sleeve 3 to pre-compress the spring 2.

[0059] Sleeve 3, bushing 6, and helmet 200 are mutually locked by transmitting torque through a rounded rectangular structure and an oblong hole. Positioning plate 4 is connected to and locked to face mask 300. When face mask 300 is locked relative to helmet 200, button shoulder 14 abuts against the inner stop 38 of sleeve 3, and the outer surface of button body 11 abuts against rolling element 5, pushing rolling element 5 out of locking hole 35, so that part of rolling element 5 enters locking groove 44. Sleeve 3 and positioning plate 4 transmit torque and are mutually locked through rolling element 5. Therefore, face mask 300 is locked relative to helmet 200.

[0060] When the rolling element 5 is a ball, the rolling element 5 is in line contact or point contact with the locking groove 44. When the rolling element is a roller structure, the rolling element 5 is in surface contact or line contact with the locking groove 44.

[0061] like Figure 10 As shown, the helmet visor locking mechanism 100 is in the unlocked state. When it is necessary to change the position of the visor 300 from the locked state, press button 1 to move it inward, compressing spring 2 and disengaging the rolling element 5 from button body 11. Because the outer diameter of button body 11 is larger than button end 12, the rolling element 5, after disengaging from button body 11, gains a radial movement space close to the axis of button 1. Rotating the visor 300, the rolling element 5 leaves the locking groove 44 under the arc compression of the locking groove 44 and rolls into the space surrounded by locking hole 35, positioning plate inner hole 43, and button end 12, thus unlocking the helmet visor locking mechanism 100 and the visor 300. Preferably, the movable distance of button 1 is adapted to the size of the rolling element 5, which is related to the axial length of button body 11, the depth of button inner hole 13, and the inner surface length of sleeve body 31.

[0062] Release button 1 and continue rotating the mask 300 to the next limiting locking angle (e.g., 90°). Under the force of spring 2, button 1 moves outward, and the button shoulder 14 squeezes the rolling element 5 to move radially away from the axis of button 1, partially entering the locking groove 44. The mask 300 returns to the locked state. The limiting angle of the mask 300 is related to the interval angle of each locking groove 44 and the position of the locking groove 44 relative to the helmet 200. The number of rolling elements 5 is no more than the number of locking grooves 44 and locking holes 35. For example, when the number of locking grooves 44 is N and they are evenly arranged, the limiting locking angle is 360° / N. If six locking grooves 44 are evenly arranged, the limiting locking angle of the mask is 60°.

[0063] In summary, the helmet visor limiting and locking mechanism provided by this utility model embodiment uses a rolling element 5 to achieve locking and unlocking, allowing the visor to be locked at the required angle to withstand deflection torque without moving. This limiting and locking mechanism can be applied to helmets with protective visors, such as bulletproof helmets, riot helmets, emergency rescue helmets, fire helmets, cycling helmets, and safety helmets. The visor can be a bulletproof visor, impact-resistant visor, sandstorm-proof visor, or UV-protective visor, etc., with certain protective functions.

[0064] It should be noted that the above embodiments are merely illustrative examples. The technical solutions of the various embodiments can be combined, and all are within the protection scope of this utility model.

[0065] The terms “thickness,” “depth,” “horizontal,” “vertical,” etc., indicating orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0066] Furthermore, in the description of this utility model, "multiple" means two or more, unless otherwise explicitly specified.

[0067] The helmet visor limiting and locking mechanism provided by this utility model has been described in detail above. Any obvious modifications made to this utility model by those skilled in the art without departing from its essential content will constitute an infringement of the patent rights of this utility model and will incur corresponding legal liability.

Claims

1. A headgear face mask position locking mechanism, characterised by Includes buttons, springs, sleeves, positioning discs, multiple rolling elements, bushings, and cap nuts; among which, The button is located inside the sleeve and protrudes from the outer end of the sleeve; the inner end of the sleeve is connected to the cap nut, and its outer end is connected to the positioning plate; the spring is located inside the sleeve, with one end in contact with the button and the other end in contact with the cap nut. The bushing is fitted onto the outer surface of the sleeve, with its outer end in contact with the sleeve and its inner end in contact with the cap nut; the rolling element is disposed between the sleeve and the positioning plate.

2. The helmet visor limiting and locking mechanism as described in claim 1, characterized in that... The button includes a button body, a button end, and a button inner hole; wherein... Both the button body and the button end are column structures with a longitudinal direction, and they are coaxial and connected; the outer diameter of the button body is larger than that of the button end; the inner hole of the button extends from the inner end face of the button body to the outside.

3. The helmet visor limiting and locking mechanism as described in claim 2, characterized in that... The sleeve includes a sleeve body, a locking ring, and a sleeve cap; wherein... The sleeve body is a tube structure with a longitudinal direction, and its outer surface is a rounded rectangular structure when projected perpendicular to the longitudinal direction; a sleeve thread is provided along the outer surface of the sleeve body. The locking ring is a tube structure with a longitudinal direction. Its inner end face contacts the outer end face of the sleeve body, and its outer end face contacts the inner end face of the sleeve cover. The inner surface of the locking ring is coplanar with the inner surface of the sleeve body, and its outer surface is a cylindrical surface with a diameter larger than the outer diameter of the sleeve body. The sleeve cover is a flange structure with an inner hole along its axis; the size of the inner hole of the sleeve cover is smaller than the inner surface size of the locking ring and the sleeve body.

4. The helmet visor limiting and locking mechanism as described in claim 3, characterized in that... The positioning disk includes a positioning disk body and a positioning disk flange; wherein... The positioning disk body is a flange structure; the positioning disk flange is a raised structure on the edge of the positioning disk body, which is adapted to the edge of the mask; The center of the positioning disc body is provided with a positioning disc inner hole, the structure of which is adapted to the outer surface of the locking ring.

5. The helmet visor limiting and locking mechanism as described in claim 1, characterized in that... The bushing includes a bushing body, a bushing partition, a bushing slip ring, and a bushing inner hole; wherein... Both the bushing body and the bushing slip ring are tubular structures with a longitudinal direction; the outer surface of the bushing body, when projected perpendicular to the longitudinal direction, is a rectangular structure with rounded ends; the outer surface of the bushing slip ring is a cylindrical surface; the bushing partition is a plate structure extending along a vertical plane; the inner end face of the bushing partition contacts the outer end face of the bushing body, and its outer end face contacts the inner end face of the bushing slip ring; the bushing body and the bushing slip ring are coaxial. The bushing inner hole extends through the bushing body, the bushing partition, and the bushing slip ring along the axial direction; the structure of the bushing inner hole is adapted to the outer surface of the sleeve body.

6. The helmet visor limiting and locking mechanism as described in claim 5, characterized in that: The cap-shaped nut is a nut structure with one end closed, and its thread is adapted to the sleeve thread; the inscribed circle of the cap-shaped nut is larger than the inner end face of the bushing body.

7. The helmet visor limiting and locking mechanism as described in claim 4, characterized in that: The locking ring has a plurality of locking holes along its circumference; the locking holes are arranged along the circumference of the locking ring and penetrate the inner and outer surfaces of the locking ring; the structure of the locking holes is adapted to the rolling element.

8. The helmet visor limiting and locking mechanism as described in claim 7, characterized in that: Multiple locking grooves are provided along the circumference of the inner hole of the positioning disk; the locking grooves are arc grooves, and their longitudinal direction extends along the thickness direction of the positioning disk; the arc curvature of each locking groove is the same and is adapted to the outer diameter of the rolling element.

9. The helmet visor limiting and locking mechanism as described in claim 8, characterized in that: The positioning disc is sleeved on the outer surface of the locking ring; the outer end face of the positioning disc body contacts the inner end face of the sleeve cover; the rolling element is disposed in the space surrounded by the locking hole, the locking groove and the button body.

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