Ratchet structure

Abstract

A ratchet structure is provided. The ratchet structure includes a housing having at least one pair of racks slidably overlapping each other. Further, a cover is coupled to the housing having a cavity. Further, the ratchet gear is removably secured within the cavity and includes a plurality of resilient ribs having one or more grooves. Further, the knob has a plurality of drive ribs configured to be received within the one or more grooves of the plurality of resilient ribs. Thus, the plurality of drive ribs facilitate movement of the plurality of resilient ribs of the ratchet gear to slide the at least one pair of racks.

Description

Technical Field

[0001] The present invention relates to a safety ratchet, and more particularly to a helmet ratchet structure. Background Art

[0002] Protective devices such as safety helmets, body protectors and many other products are provided with fasteners, which are used to connect these products to other objects. In particular, safety helmets are used at construction sites where they need to be fixed on the user's head. When using safety helmets, they are required to withstand continuous movement. In order to secure the safety helmets, multiple straps are needed to tighten the safety helmets. Such straps use buckles to tighten the straps of the helmet. However, these straps are not able to withstand continuous movement of the helmet. In addition, these straps often cause the helmet to move out of its original position due to accidental or unintentional readjustment. Usually, different ratchets are used to tighten the helmet on the head. However, these ratchets do not provide the user with easy readjustment options and do not prevent unintentional readjustment of the straps and the helmet. Summary of the invention

[0003] In order to provide a basic understanding of some aspects of the present disclosure, a simplified overview is given below. This overview is not an extensive review and is neither intended to identify key or important elements nor to delimit the scope of these elements. Its purpose is to present some concepts of the described features in a simplified form as a prelude to a more detailed description presented later.

[0004] In an exemplary embodiment, a ratchet structure is provided. The ratchet structure includes a housing having at least one pair of racks slidably overlapping each other. In addition, a cover is coupled to the housing and has a cavity. In addition, a ratchet gear is detachably fixed in the cavity. The ratchet gear includes a plurality of elastic ribs having one or more grooves. In addition, the knob has a plurality of drive ribs, which are configured to be received in one or more grooves of the plurality of elastic ribs. Thereafter, the plurality of drive ribs facilitate movement of the plurality of elastic ribs of the ratchet gear to slide the at least one pair of racks.

[0005] In some embodiments, a rod is attached to the housing, the rod extending radially through the cover and the ratchet gear.

[0006] In some embodiments, the cavity is manufactured with a first set of snaps and the ratchet gear is manufactured with a second set of snaps. In some embodiments, the first set of snaps engages with the plurality of resilient ribs and the second set of snaps engages with the at least one pair of racks for adjusting the ratchet gear.

[0007] In some embodiments, the first set of catches engage with the second set of catches to interlock with each other and restrict movement of the ratchet gear, which in turn locks movement of the at least one pair of racks.

[0008] In some embodiments, the at least one pair of racks are manufactured with a notched track that engages with the second set of snaps for adjusting the ratchet gear.

[0009] In some embodiments, the plurality of resilient ribs are manufactured with at least one protruding section that deforms when in contact with the second set of snaps of the ratchet gear.

[0010] In some embodiments, the knob includes one or more recesses for properly retaining the knob. In some embodiments, the knob includes a plurality of clips configured to couple the knob to the cover.

[0011] In some embodiments, the ratchet gear has at least one positioning column for providing support to the plurality of elastic ribs.

[0012] In another exemplary embodiment, a helmet ratchet structure is provided. The helmet ratchet structure includes a shell attached to the helmet via at least one pair of racks that are slidably overlapped with each other. In addition, a cover is coupled to the shell and has a cavity in which a first set of snaps is manufactured. In addition, the ratchet gear is detachably fixed in the cavity and includes a second set of snaps and a plurality of elastic ribs with one or more grooves. In addition, the knob has a plurality of drive ribs that are configured to be received in the one or more grooves. The plurality of drive ribs facilitate the movement of the plurality of elastic ribs of the ratchet gear to slide the at least one pair of racks, and the second set of snaps engages with the first set of snaps to limit the movement of the ratchet gear, which in turn locks the movement of the at least one pair of racks to tighten the helmet.

[0013] The above overview is provided only to summarize some example embodiments to provide a basic understanding of some aspects of the present invention. Therefore, it will be appreciated that the above embodiments are merely examples and should not be construed as narrowing the scope or spirit of the present disclosure in any way. It will be appreciated that in addition to those embodiments summarized here, the scope of the present disclosure encompasses many potential embodiments, some of which will be further described below. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Having generally described certain example embodiments of the present disclosure, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and in which:

[0015] Figure 1A illustrates a front view of a ratchet structure according to the present disclosure;

[0016] Figure 1B illustrates an exploded view of a ratchet structure according to the present disclosure;

[0017] Figure 2A illustrates a front view of a ratchet structure according to the present disclosure having a ratchet gear coupled to at least a pair of racks;

[0018] Figure 2B illustrates a perspective view of a ratchet structure with a cover according to the present disclosure;

[0019] Figure 2C illustrates an isometric view of a ratchet gear according to the present disclosure;

[0020] Figure 3A illustrates another perspective view of a ratchet structure according to the present disclosure, wherein a knob is removably coupled to a cover and a ratchet gear;

[0021] Figure 3B illustrates a top view of a knob mounted on a ratchet gear according to the present disclosure;

[0022] Figure 3C-3D illustrates a cross-sectional view of a ratchet structure according to the present disclosure;

[0023] Figure 3E illustrates another perspective view of a ratchet structure according to the present disclosure, wherein a ratchet gear is coupled to at least a pair of racks;

[0024] Figure 4A The ratchet structure according to the present disclosure is illustrated, wherein the knob is rotated in a clockwise direction;

[0025] Figure 4B The ratchet structure according to the present disclosure is illustrated, wherein the knob is rotated in a counterclockwise direction;

[0026] Figure 4C illustrates the extension and retraction movement of at least one pair of racks according to the present disclosure;

[0027] Figure 5 The ratchet structure in a locked state according to the present disclosure is illustrated;

[0028] Fig. 6A A top view of a ratchet structure according to another embodiment of the present disclosure is illustrated;

[0029] Figure 6B A front view of a ratchet structure according to another embodiment of the present disclosure is illustrated;

[0030] Figure 6C A side view of a ratchet structure according to another embodiment of the present disclosure is illustrated;

[0031] Fig.6D A rear view of a ratchet structure according to another embodiment of the present disclosure is illustrated;

[0032] Fig. 6E An exploded view of a ratchet structure according to another embodiment of the present disclosure is illustrated; and

[0033] Figure 7A side view of a helmet coupled to a ratchet structure according to the present disclosure is illustrated. DETAILED DESCRIPTION

[0034] The exemplary embodiments described herein provide details for illustrative purposes, and there may be many variations in structure and design. However, it should be appreciated that the embodiments are not limited to the specific disclosed embodiments shown or described. It is to be understood that various omissions and substitutions of equivalents may be considered when circumstances may suggest or provide convenience, but these are intended to cover applications or implementations without departing from the spirit or scope of the claims.

[0035] In addition, it is to be understood that the words and terms used herein are for descriptive purposes and should not be considered limiting. The terms "a", "an" and "the" herein do not indicate a limitation of quantity, but rather indicate the presence of at least one of the referenced objects. It will also be understood that the terms "include" and / or "comprise" when used in this specification specify the presence of stated features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or combinations thereof. The same numbers in the figures represent the same parts.

[0036] Embodiments of the present disclosure will be described more fully below with reference to the accompanying drawings, wherein like reference numerals denote like elements throughout the several drawings, and example embodiments are shown therein. However, embodiments of the present disclosure may be specifically implemented in alternative forms and should not be construed as being limited to the embodiments set forth herein. The examples set forth herein are non-limiting examples and are merely examples among other possible examples.

[0037] Various embodiments of the present disclosure disclose a ratchet structure for a safety helmet. In some embodiments, the present disclosure discloses that the ratchet structure can be coupled to the back side of the helmet. The ratchet structure can employ a strap with an adjustment mechanism to loosen or tighten the ratchet structure with the helmet. In addition, the user can easily adjust the tightening and loosening of his / her helmet without removing the helmet from his / her head.

[0038] Figure 1A FIG. 1 shows a front view of a ratchet structure 100 according to the present disclosure. Figure 1B To describe Figure 1A .

[0039] In some embodiments, the ratchet structure 100 can be provided on a helmet (not shown) to tighten or loosen the helmet on the user's head. The ratchet structure 100 can be coupled to one or more straps (not shown) of the helmet to tighten or loosen the straps according to the user's convenience. In addition, the ratchet structure 100 can be configured to tighten the position of the one or more straps so that the helmet provided on the user's head does not become loose during sudden movements of the helmet.

[0040] The ratchet structure 100 may include a housing 102, a cover 104, and a knob 106. The housing 102 may be a hollow structure that forms a space for incorporating at least one pair of racks 108. The at least one pair of racks 108 may be incorporated into the housing 102 so that, in some cases, the at least one pair of racks 108 may extend from both ends 110 of the housing 102 to the outside. In some embodiments, the at least one pair of racks 108 may be retracted from each end 110 to the inside of the housing 102. The at least one pair of racks 108 may slide within the housing 102 in such a manner that the at least one pair of racks 108 may partially overlap each other. In some embodiments, each end 112 of the at least one pair of racks 108 may be attached to a strap of a helmet. The extension and retraction of the at least one pair of racks 108 may stretch or release the strap of the helmet. Figures 2A-3E The detailed movement of at least one pair of racks 108 is described.

[0041] In addition, the housing 102 can be detachably coupled to the cover 104. In some embodiments, the size of the cover 104 can be slightly smaller than the size of the housing 102. The difference in size can allow the cover 104 to fit snugly inside the housing 102. In some embodiments, the cover 104 can be coupled to the knob 106. The knob 106 can be configured to be rotated by a user in a clockwise direction or in a counterclockwise direction. In addition, the knob 106 can be manufactured with one or more recesses 114. The one or more recesses 114 can allow the user to properly grip the knob 106 by placing a finger between the one or more recesses 114. In some example embodiments, the knob 106 can be rotated in a clockwise direction or a counterclockwise direction to move the at least one pair of racks 108 to the inside or outside of the housing 102, which will Figures 4A-4C In some embodiments, the ratchet structure 100 can produce a clicking sound during clockwise rotation of the knob 106, which indicates tightening of the helmet.

[0042] In addition, if Figure 1BAs shown, the cover 104 can be manufactured with at least one buckle 116. In some embodiments, the at least one buckle 116 can be configured with a cavity 118. The cavity 118 manufactured in the at least one buckle 116 can form an empty space. In some embodiments, the empty space of the cavity 118 can allow the at least one buckle 116 to contain at least one rod 120 of the housing 102, which can removably couple the cover 104 to the housing 102. In addition, the housing 102 can be mounted with a rod 122. The rod 122 can extend radially outside the housing 102. In some embodiments, the rod 122 can act as a pivot point to rotate the knob 106 in a clockwise and / or counterclockwise direction.

[0043] In addition, the cover 104 can be manufactured with a cavity 124. In some embodiments, the cavity 124 can be manufactured with a track 126. It can be noted that the cavity 124 can be referred to as an annular segment. In some example embodiments, the track 126 can correspond to a circular protruding segment integrated around the periphery of the cavity 124. In addition, the track 126 can be coupled to a plurality of clips (not shown), which are manufactured with the knob 106. This coupling of the track 126 with the plurality of clips allows the cover 104 to be attached to the knob 106 and provides a guide path for the rotation of the knob 106 in a clockwise or counterclockwise direction. In some embodiments, the cavity 124 can have different diameters. In addition, the cavity 124 can be manufactured with a first set of buckles 128. In some embodiments, the first set of buckles 128 can be manufactured with a plurality of gear teeth. In addition, the cavity 124 of the cover 104 can be configured to accommodate a ratchet gear 130. The ratchet gear 130 can be configured to rotate in a clockwise or counterclockwise direction with the movement of the knob 106. The ratchet gear 130 may include a second set of buckles 132, a plurality of elastic ribs 134, and at least one positioning column 136. The second set of buckles 132 and the plurality of elastic ribs 134 may be manufactured on opposite surfaces of the ratchet gear 130. The detailed working of the second set of buckles 132, the plurality of elastic ribs 134, and the at least one positioning column 136 may be described in detail. Figures 2A-3E Further described in .

[0044] In addition, the ratchet gear 130 can be manufactured with a hole 138. The hole 138 can allow the rod 122 to extend radially through the cover 104 and the ratchet gear 130. In addition, the plurality of resilient ribs 134 can be manufactured with one or more grooves 140, which can be Figures 3A-3E It will be apparent to those skilled in the art that the above-described components of the ratchet structure 100 are provided for illustrative purposes only and do not depart from the scope of the present disclosure.

[0045] Figure 2AFIG. 1 shows a front view of a ratchet structure 100 according to the present disclosure, the ratchet structure 100 having a ratchet gear 130 coupled to the at least one pair of racks 108. Figure 2B-2C describe Figure 2A .

[0046] In some embodiments, the at least one pair of racks 108 may be manufactured with a plurality of teeth 202. It may be noted that the plurality of teeth 202 may also be referred to as a notched track. The plurality of teeth 202 may be manufactured to each of the at least one pair of racks 108 such that the plurality of teeth 202 of each of the at least one pair of racks 108 may be positioned parallel to the space between the at least one pair of racks 108. Such a space may allow the second set of snaps 132 of the ratchet gear 130 to be positioned between the at least one pair of racks 108 and the plurality of teeth 202. The interconnection between the at least one pair of racks 108 and the second set of snaps 132 may allow the rotational motion of the ratchet gear 130 to be converted into a linear motion carried by the at least one pair of racks 108. In some embodiments, the clockwise rotation of the ratchet gear 130 may help the at least one pair of racks 108 to retract into the interior of the housing 102. In some embodiments, the counterclockwise rotation of the ratchet gear 130 may help the at least one pair of racks 108 to extend outside the housing 102.

[0047] In some embodiments, Figure 2C As shown, the plurality of resilient ribs 134 may also be manufactured with protruding sections 204. The interconnection of the plurality of teeth 202 with the second set of buckles 132 may allow the plurality of protruding sections 204 of the plurality of resilient ribs 134 to overlap with the first set of buckles 128, as shown. Figure 2B During the rotational movement of the ratchet gear 130, the protruding section 204 of the elastic rib 134 periodically collides with the second set of buckles 132, which deforms the protruding section 204. The deformed protruding section 204 further rotates and collides with the second set of buckles 132, thereby generating a click sound indicating that the ratchet structure 100 is tightened with the helmet.

[0048] Figure 3A A perspective view of a ratchet structure 100 according to the present disclosure is illustrated, wherein the knob 106 is separated from the cover 104 and the ratchet gear 130. Figure 3B-3C To describe Figure 3A .

[0049] In some embodiments, the knob 106 can be manufactured with a plurality of clips 302. The plurality of clips 302 can be manufactured at one side of the knob 106 to interlock with the track 126 manufactured around the cavity 124, such as Figure 3BThe interconnection of the plurality of clips 302 and the track 126 may allow the knob 106 to be coupled to the cover 104. In some embodiments, the plurality of clips 302 and the track 126 may also provide the knob 106 with smooth rotational movement relative to the cover 104.

[0050] In some embodiments, the knob 106 may be manufactured with a plurality of drive ribs 304. The plurality of drive ribs 304 may be protrusions that may be inserted into one or more grooves 140 of the plurality of resilient ribs 134 when the knob 106 is coupled to the cover 104, such as Figure 3C As shown. Once the plurality of drive ribs 304 are inserted into the one or more grooves 140 of the plurality of resilient ribs 134, they can facilitate the rotational movement of the knob 106, and thus cause the rotational movement of the ratchet gear 130. Once the knob 106 is coupled to the cover 104, the plurality of drive ribs 304 can push the plurality of resilient ribs 134. The force applied by the plurality of drive ribs 304 to the plurality of resilient ribs 134 can cause the rotational movement of the ratchet gear 130.

[0051] Figure 4A-4B The ratchet structure 100 according to the present disclosure is illustrated wherein the knob 106 is rotated in a clockwise rotation 402 and a counterclockwise rotation 404. Figure 4C describe Figure 4A-4B .

[0052] In some embodiments, the clockwise rotation 402 of the knob 106 can rotate the ratchet gear 130, which further retracts the at least one pair of racks 108 into the interior of the housing 102. Once the knob 106 is rotated in a clockwise rotation 402 by the user by grasping one or more recesses 114, the plurality of drive ribs 304 can push the plurality of resilient ribs 134 in a clockwise rotation 402. In addition, through the rotational movement of the plurality of resilient ribs 134, the protruding section 204 can engage with the first set of catches 128. As previously described, such engagement of the protruding section 204 with the first set of catches 128 can produce a clicking sound. In addition, the rotational movement of the ratchet gear 130 can assist in the rotational movement of the second set of catches 132. The engagement of the second set of catches 132 with the plurality of teeth 202 can further retract the at least one pair of racks 108 into the interior of the housing 102, as Figure 4C As shown by arrow 406 in FIG.

[0053] In some embodiments, the counterclockwise rotation 404 of the knob 106 can rotate the ratchet gear 130, which in turn causes the at least one pair of racks 108 to extend outside the housing 102. Once the knob 106 is rotated in a counterclockwise rotation 404 by the user by gripping the one or more recesses 114, the plurality of drive ribs 304 can push the plurality of resilient ribs 134 in a counterclockwise rotation 404. In addition, the protruding section 204 can thereby engage with the first set of catches 128 through the rotational movement of the plurality of resilient ribs 134. In addition, the rotational movement of the ratchet gear 130 can facilitate the rotational movement of the second set of catches 132. Such engagement of the second set of catches 132 with the plurality of teeth 202 can further extend the at least one pair of racks 108 outside the housing 102, as shown in FIG. Figure 4C As shown by another arrow 408 in FIG.

[0054] Figure 5 The ratchet structure 100 according to the present disclosure is shown in a locked state. Figures 1A-4B describe Figure 5 .

[0055] In some embodiments, once the at least one pair of racks 108 is locked in a desired position, the ratchet structure 100 may be adapted to be switched to a locked state by a user. The ratchet structure 100 may be switched to a locked state by a user by pulling the knob 106. Once the knob 106 may be pulled, the ratchet gear 130 slides partially through the cavity 124 along the knob 106 to the outside. The sliding movement of the ratchet gear 130 causes the interlocking disengagement between the second set of snaps 132 and the plurality of teeth 202 of the at least one pair of racks 108. Similarly, the plurality of resilient ribs 134 disengage from the first set of snaps 128 to allow the second set of snaps 132 to engage with the first set of snaps 128. This interconnection of the first set of snaps 128 with the second set of snaps 132 locks the rotational movement of the ratchet gear 130, and thereby secures the position of the at least one pair of racks 108. The locked state of the ratchet structure 100 prevents unwanted or accidental movement of the straps attached to the at least one pair of racks 108 and thereby prevents the helmet being fitted to the user from becoming loose.

[0056] Fig. 6A FIG. 6 is a front view of a ratchet structure 600 according to another embodiment of the present disclosure. Figure 6B-6E describe Fig. 6A .

[0057] In some embodiments, the ratchet structure 600 can be configured with the housing 102, the cover 104, and the knob 106, as previously described. In addition, each end 112 of the at least one pair of racks 108 can be manufactured with at least one buckle 602. The at least one buckle 602 can be configured to couple each end 112 of the at least one pair of racks 108 to a strap of the helmet. Extension and retraction of the at least one pair of racks 108 can allow the at least one buckle 602 to stretch or release the strap, and thereby tighten or loosen the helmet. It can be noted that the at least one buckle 602 can be manufactured in a circular orientation, such as Figure 6C As shown. In some embodiments, the shape and size of the at least one buckle 602 may vary based on the application. It will be apparent to those skilled in the art that the at least one buckle 602 may not be limited to being coupled to a belt, it may be attached to any entity that is configured to be stretched or released along the movement of the at least one pair of racks 108.

[0058] In some embodiments, one or more recesses 114 of the knob 106 may be manufactured with a knurled pattern 604, such as Figure 6B-6D As shown. Knurl pattern 604 can be a cross-shaped pattern that can be configured to provide an additional grip for the user when used to hold knob 106. Knurl pattern 604 can provide a rough surface compared to a smooth surface for the user's fingers. Knurl pattern 604 can have indentations that limit the sliding of the user's fingers. This improved grip can be particularly useful in applications where knob 106 may be frequently used in wet or oily conditions. In addition, knurl pattern 604 can also improve the user's grip when wearing gloves. In some example embodiments, knurl pattern 604 can be manufactured as straight lines, cross-shaped lines, or angled lines.

[0059] It should be noted that the components and operating mechanisms described above for the ratchet structure 100 may also be applicable to the ratchet structure 600 without departing from the scope of the present disclosure.

[0060] Figure 7 A side view of a helmet 702 coupled to a ratchet structure 100 according to the present disclosure is illustrated. Figure 1A-6E describe Figure 7 .

[0061] In some embodiments, the ratchet structure 100 can be coupled to at least one strap 704 of the helmet 702. The ratchet structure 100 can be configured to loosen or tighten the at least one strap 704 of the helmet 702. Tightening of the at least one strap 704 can allow the helmet 702 to be securely tightened on the head 706 of the user 708. In some embodiments, based on the size of the head 706, the user 708 can rotate the knob 106 of the ratchet structure 100 in a clockwise or counterclockwise direction. Once the helmet 702 is comfortably fixed on the head 706 of the user 708, the user 708 can rotate the knob 106. The rotation of the knob 106 can lock the ratchet structure 100. The locked state of the ratchet structure 100 can thereby limit the rotational movement of the knob 106 and the lateral movement of the at least one pair of racks 108. The limited movement of the at least one pair of racks 108 can thereby lock the position of the at least one strap 704. It can be noted that the fastening position of the at least one strap 704 can help the user 708 keep the helmet 702 fastened on the head 706 for a longer period of time. In addition, in the case of movement of the user 708 and the head 706, the helmet 702 may not move laterally.

[0062] This ratchet structure 100 can help loosen and tighten the helmet 702 according to the convenience of the user 708. Such clockwise and counterclockwise rotation of the knob 106 with the knurled pattern 604 grip can provide ease of loosening and tightening the ratchet structure 100. Therefore, the wearer can easily adjust the helmet 702 according to the working conditions.

[0063] It will be apparent to those skilled in the art that the above-described ratchet structure 100 may be applicable to any design, such as a guard, a tightening strap, etc., without departing from the scope of the present disclosure.

[0064] As will be appreciated by those skilled in the art, aspects of the present disclosure may be embodied as systems, methods or computer program products. Therefore, aspects of the various embodiments may take the form of complete hardware embodiments, complete software embodiments (including firmware, resident software, microcode, etc.) or embodiments combining software and hardware aspects, which are generally all referred to herein as "circuits", "modules", "systems" or "subsystems". In addition, aspects of the present disclosure may take the form of computer program products, which are contained in one or more computer-readable media, which contain computer-readable program code.

[0065] The foregoing descriptions of specific embodiments have been presented for the purpose of illustration and description. They are not intended to be exhaustive or to limit the embodiments to the precise form disclosed, and it is apparent that many modifications and variations are possible in light of the above teachings. These embodiments are selected and described in order to best explain their principles and practical applications, and thereby enable other technical personnel in the art to best utilize various embodiments with various modifications to suit the intended specific purposes. It should be understood that various omissions and substitutions of equivalents may be considered when circumstances may suggest or provide convenience, but these are intended to cover applications or implementations without departing from the spirit or scope of the claims. The following claims are by no means intended to limit the scope of the embodiments to the specific embodiments described herein.

Claims

1. A ratchet structure, comprising: a housing having at least one pair of racks slidably overlapping each other; a cover coupled to the housing and having a cavity; a ratchet gear removably secured within the cavity, wherein the ratchet gear includes a plurality of resilient ribs having one or more grooves; and a knob having a plurality of drive ribs configured to be received in one or more grooves of the plurality of resilient ribs, Wherein, the plurality of driving ribs facilitate movement of the plurality of elastic ribs of the ratchet gear to slide the at least one pair of racks.

2. The ratchet structure according to claim 1, wherein: A rod is attached to the housing, the rod extending radially through the cover and the ratchet gear.

3. The ratchet structure according to claim 1, wherein: The cavity is manufactured with a first set of snaps and the ratchet gear is manufactured with a second set of snaps.

4. The ratchet structure according to claim 3, wherein: The first set of snaps engages the plurality of resilient ribs and the second set of snaps engages the at least one pair of racks for adjusting the ratchet gear.

5. The ratchet structure according to claim 3, wherein: The first set of catches engages with the second set of catches to interlock with each other and restrict movement of the ratchet gear, which in turn locks movement of the at least one pair of racks.

6. The ratchet structure according to claim 3, wherein: The at least one pair of racks is manufactured with a notched track that engages with a second set of snaps for adjusting the ratchet gear.

7. The ratchet structure according to claim 3, wherein: The plurality of elastic ribs are manufactured with at least one protruding section that is deformed when in contact with the second set of snaps of the ratchet gear.

8. The ratchet structure according to claim 1, wherein: The knob has one or more recesses for properly retaining the knob.

9. The ratchet structure according to claim 1, wherein: The knob includes a plurality of clips configured to couple the knob to the cover.

10. The ratchet structure according to claim 1, wherein: The ratchet gear has at least one positioning column for providing support to the plurality of elastic ribs.

11. A helmet ratchet structure, comprising: a housing attached to the helmet via at least one pair of racks that slidably overlap each other; a cover coupled to the housing and having a cavity fabricated with a first set of snaps; a ratchet gear removably secured within the cavity, wherein the ratchet gear includes a second set of snaps and a plurality of resilient ribs having one or more grooves; and a knob having a plurality of drive ribs configured to be received within the one or more grooves, Wherein, the multiple driving ribs assist the movement of the multiple elastic ribs of the ratchet gear to slide the at least one pair of racks, and the second group of buckles engages with the first group of buckles to limit the movement of the ratchet gear, which in turn locks the movement of the at least one pair of racks to tighten the helmet.

12. The helmet ratchet structure according to claim 11, wherein: A rod is attached to the housing, the rod extending radially through the cover and the ratchet gear.

13. The helmet ratchet structure according to claim 11, wherein: The first set of snaps engages the plurality of resilient ribs and the second set of snaps engages the at least one pair of racks for adjusting the ratchet gear.

14. The helmet ratchet structure according to claim 11, wherein: The at least one pair of racks is manufactured with a notched track that engages with a second set of snaps for adjusting the ratchet gear.

15. The helmet ratchet structure according to claim 11, wherein: The plurality of elastic ribs are manufactured with at least one protruding section that is deformed when in contact with the second set of snaps of the ratchet gear.

16. The helmet ratchet structure according to claim 11, wherein: The knob has one or more recesses for properly retaining the knob.

17. The helmet ratchet structure according to claim 11, wherein: The knob includes a plurality of clips configured to couple the knob to the cover.

18. The helmet ratchet structure according to claim 11, wherein: The ratchet gear has at least one positioning column for providing support to the plurality of elastic ribs.

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