Passive deflection-sensitive mechanism for helmets

Abstract

The present invention discloses a novel, passive deflection-sensitive mechanism designed for applications such as helmets. This mechanism enhances safety by allowing the movement and decoupling of specific helmet parts when applied forces exceed a predetermined threshold. The mechanism comprises an anchor socket and a deflect pin, whose extended shaft facilitates deflection and decoupling of the connected parts of a helmet under lateral forces. This decoupling reduces rotational and linear forces on the brain during impact, thereby decreasing the risk of head injury and concussion. Prototype testing with this mechanism demonstrated a significant reduction in force applied to the brain, making it a promising solution for head protection equipment. While the mechanism is frangible and absorbs only a negligible amount of energy, it contributes to force reduction by enabling part decoupling upon impact. Additionally, the mechanism is adaptable for various applications requiring movement and detachment of parts under specific conditions.

Description

DescriptionTitle of Invention: A Novel Passive Deflection-Sensitive MechanismBackground Art

[0001] Passive mechanical mechanisms have a rich history in engineering, dating back to ancient civilizations. These mechanisms operate without the need for continuous energy or power input, relying on fundamental principles of mechanics and materials science. They encompass a wide range of devices, from simple gears and levers to complex systems like clockworks and mechanical linkages.

[0002] Over the centuries, innovations in passive mechanical mechanisms have paved the way for advancements in fields such as automation, robotics, safety and aerospace engineering. These mechanisms are valued for their reliability, efficiency, and minimal maintenance requirements.

[0003] In modem applications, passive mechanical mechanisms are integral to technologies like shock absorbers, seatbelts, fire distinguishers, thermostats, and mechanical governors. Their design often involves precise calculations to ensure optimal performance under various conditions. By leveraging the principles of inertia, geometry, gravity, elasticity, friction, and magnetism, these mechanisms contribute to the development of sustainable and energy-efficient solutions across industries.

[0004] Passive mechanisms are all about intelligent design and harnessing natural forces. They are everywhere; constantly working behind the scenes to make life smoother, safer, and more efficient. When designing a passive mechanism, it is crucial to create the simplest mechanism that effectively performs the required function. In other words, a simpler mechanism often indicates a more intelligent design.Summary of Invention

[0005] In the disclosed invention, a novel passive deflection-sensitive mechanism is introduced. The mechanism allows attached parts to be decoupled when the force exceeds a certain threshold through the deflection of the shaft and the deformation of other parts.

[0006] One general aspect provides a passive deflection-sensitive mechanism for attaching certain parts of a helmet, consisting of a deflect pin and an anchor socket. The deflect pin comprises a long shaft and a base that allows the deflect pin to deflect when the lateral component of the force applied to the mechanism exceeds a certain threshold. The deflection of the deflect pin in the first phase allows the base of the pin to move relative to the anchor socket. In the second phase, when the force increases beyond a certain threshold, the deflect pin detaches from the anchor socket, resulting in the failure of the attachment provided by the mechanism. This detachment enables certainparts of the helmet to move relative to each other, which helps significantly reduce the rotational and linear forces applied to the head during an impact.

[0007] The invention provides a cost-effective solution that is lightweight and easy to install, suitable for use in helmets or other applications where attachment failure under a certain amount of force can be beneficial. One general aspect provides a passive deflection-sensitive mechanism that is frangible and absorb only a negligible amount of force or impact energy by its deflection, deformation, or detachment. The main goal of the invention is to allow parts attached by the mechanism to move or detach when the force applied to the disclosed mechanism exceeds certain thresholds, and in the absence of such forces, keep the parts attached.

[0008] One general aspect provides a passive deflection-sensitive mechanism where the length of the shaft is at least three times the diameter of the shaft. This aspect allows the shaft to deflect when the lateral component of an applied force exceeds a certain threshold. Depending on the material(s) used for making the mechanism, its configuration, and the application, the shaft length can be determined. For instance, according to our prototyping and impact testing for bicycle helmets using an advanced test rig with a humanoid headform, when thermoplastic nylon is used, the length of the shaft should be approximately four times the diameter of the shaft to hold the parts in place when the helmet is worn, and allow the attached parts by the disclosed mechanism to move or decouple when the force exceeds certain thresholds during impact.

[0009] Using the invented mechanism in bicycle helmets along with the advanced design of the helmet used in our testing, the rotational and linear forces applied to the head were reduced by over 50% compared to conventional helmets. Such a reduction can significantly mitigate the risk of head injury and concussion. The disclosed mechanism is frangible and absorbs only a negligible amount of impact energy; however, by allowing the parts to decouple during impact, it assists other parts in reducing forces applied to the head during impact. The passive deflection-sensitive mechanism can be designed for various applications to allow parts movement and detachments where they are desired.Brief Description of Drawings

[0010] The foregoing aspects of the present disclosure will become more readily appreciated as the same will become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawing, wherein:

[0011] [Fig.l] illustrates the deflect pin in accordance with a number of embodiments and comprises three parts. Part A of [Fig.l] shows an isometric view of the deflect pin, Part B of [Fig.l] shows a side view, and Part C of [Fig.l] shows a top view.

[0012] [Fig-2] illustrates the anchor socket in accordance with a number of embodiments and comprises three parts. Part A of [Fig.2] shows an isometric view of the anchor socket, Part B of [Fig.2] shows a side view, and Part C of [Fig.2] shows a top view.

[0013] [Fig.3] shows parts A and B attached together by means of an anchor socket and a deflect pin that are partially embedded in component A and component B, respectively.

[0014] [Fig.4] illustrates comparative side views of fastener assemblies and comprises two parts. Part A of [Fig.4] shows a side view of a conventional male snap fastener used in various applications, including head-protective equipment such as helmets, and Part B of [Fig.4] shows a side view of the deflect pin of the present invention in accordance with a number of embodiments.

[0015] [Fig.5] shows a passive deflection- sensitive mechanism used to attach the outer shell of a helmet to its shock-absorbing liner.

[0016] [Fig.6] shows a passive deflection- sensitive mechanism used to attach modular shock-absorbing liners of a helmet to its base shock-absorbing liner.Description of Embodiments

[0017] In the following section, specific details are explained to provide an in-depth understanding of the exemplary embodiments of the present invention. It will be apparent to one familiar with the art that the embodiments shown may be realized without embodying every specific detail. The embodiments of the present invention may also employ any combination of features described below.

[0018] Unless otherwise specified, any components, features, or elements described herein as singular or plural are intended to be interchangeable, as deemed necessary, to achieve the functionality or objectives of the invention. The use of singular terms should not be construed as limiting, and plural terms may include singular variations, depending on the specific context and implementation.

[0019] The following description provides illustrations of a novel passive deflectionsensitive mechanism to include the claimed features.

[0020] Head injuries and concussions are significant issues worldwide, and while helmets are effective, their designs remain far from perfect. A key challenge in head protection is that if helmet components do not move during milliseconds of impact, they cannot adequately protect the head from certain injurious forces. Although there have been attempts to implement active systems using sensors, these systems cannot always respond quickly enough in certain incidents, and some may even fail to pass helmet certification requirements.

[0021] The goal of the present invention was to develop a mechanism that holds helmet components in place and, under specific conditions, allows these parts to move relative to each other. Multiple mechanisms were developed, and prototype helmets wereproduced and tested in an advanced impact testing facility. This research led to the development of a passive mechanism capable of instantaneously reacting to impact and permitting the desired movement of the helmet’s components.

[0022] The present invention introduces a novel, passive deflection- sensitive mechanism designed to deflect and decouple under specific conditions. When the lateral component of the force applied to the mechanism exceeds a certain threshold, the components attached by the mechanism can move and detach from each other. This detachment activates the system, initiating a task through mechanical movement.

[0023] The mechanism comprises a deflect pin and an anchor socket. The deflect pin comprises a base, a relatively long shaft, and a head. The shaft length is at least three times the diameter of the shaft. The length of shaft is designed to allow the deflect pin to deflect when the lateral component of the force applied to the mechanism exceeds a certain threshold. The deflection first results in the movement of the base of the deflect pin relative to the anchor socket. This movement, consequently, translates to the finite movement of the parts attached by the mechanism relative to each other. The movement can be translational, rotational or a combination of both. When the lateral component of the force exceeds a higher second threshold, the base of the deflect pin moves further, and the deflect pin detaches from the anchor socket.

[0024] By using an elongated shaft for the deflect pin, the mechanism becomes deflectionsensitive, allowing it to decouple or detach the connected objects if the force exceeds a certain threshold. To ensure that the shaft deflects sufficiently, the base of the deflect pin and the receptacle of the anchor socket must be positioned such that they are at least a minimum distance away from each other equal to twice the diameter of the shaft. This can be achieved by partially embedding and / or recessing the deflect pin and the anchor socket in the parts they are attaching to each other, thereby maintaining the minimum distance between the base of the deflect pin and the receptacle when the parts are attached by the mechanism.

[0025] The simplicity and effectiveness of the deflection- sensitive mechanism make it ideal for various applications, including helmet parts. This passive system operates without external input, power, or active control, relying instead on its inherent design, material, and the receiving force to function. This makes it ideal for safety applications and beyond, showcasing its innovative nature and non-obviousness, as similar solutions would have been adopted previously if they existed.

[0026] For instance, helmets can be designed so that the movement of certain parts during impact enhances the protection of the head against rotational and linear forces. By using a passive releasing mechanism like the disclosed passive deflection- sensitive mechanism in helmets, it is possible to significantly enhance the protection of the head against injury and concussion.

[0027] The disclosed passive deflection-sensitive mechanism is designed to be frangible and fail by deflecting, deforming, and detaching during its usage when the lateral component of the force applied to the mechanism exceeds a certain threshold. Therefore, the disclosed mechanism does not absorb a tangible or substantial amount of energy from the applied force or impact to the object equipped with the said mechanism. For instance, when the disclosed mechanism is used in a helmet, the mechanism absorbs only a negligible amount of impact energy during an impact. However, by allowing parts to decouple and move relative to each other, the mechanism helps other parts in the helmet to mitigate the impact force that otherwise would have been applied to the head during an impact As used herein, “absorbs only a negligible amount of impact energy” means that while the deflect pin may undergo deflection or deformation before or during detachment from the anchor socket, the energy absorbed by these actions during a typical helmet impact is so small relative to the total impact energy that it can be disregarded in practical energy calculations. The protective function of the mechanism arises not from energy absorption, but from enabling controlled movement and detachment of helmet parts once impact thresholds are exceeded.

[0028] For the purposes of the disclosed invention, the following definitions apply: a) Lateral Component of a Force: A component of a force whose direction is perpendicular to the shaft’s axial direction, b) The axial direction of the shaft is measured prior to any force being applied to the mechanism, c) Mechanism: This term refers to the disclosed passive deflection-sensitive mechanism, unless stated otherwise, d) Force: A force that can comprise both lateral and radial components, e) Radial (Normal) Force: A force whose direction is parallel to the shaft’s axial direction. The axial direction of the shaft is measured prior to any force being applied to the mechanism, f) Deflection: This term refers to bending deformation of the deflect pin and its shaft under an applied lateral load, g) Decoupling and Detaching: These terms are used interchangeably. When two parts are described as “detaching” or “decoupling” from one another, it inherently implies that they are also moving relative to each other, h) Attachment Failure: Occurs when a force is applied to the mechanism, causing the deflect pin to detach from the anchor socket, i) Diameter and Equivalent Diameter: These terms are used interchangeably, j) Passive Mechanism: A passive mechanism is a mechanism that operates without the need for active control or external energy or power input. It relies entirely on its design, configuration, materials, and forces to function.

[0029] The proposed mechanism stays attached when a small amount of force is applied to the mechanism, which varies depending on the application, configuration, dimension, and materials used for the mechanism. The deflect pin can be attached or detachedby radial pushing or pulling force that is mainly parallel to the shaft’ s axial direction for assembly or disassembly of the parts. The force required for assembling or disassembling is usually defined based on the method of assembly and disassembly of the parts. Based on the application, configuration, and material used, the dimension of the mechanism can be determined.

[0030] For example, when thermoplastics such as nylon (polyamide) or similar are used for the mechanism of a helmet, the suitable length of the shaft was determined to be approximately four times its diameter. By considering 2.5mm for the shaft diameter, the length of the shaft will be approximately 10mm.

[0031] Finding the right diameter is also important and challenging, as a small diameter for the shaft results in buckling of the deflect pin during attachment, and a large diameter would not work in the available space in a helmet. In addition, by considering the thickness of approximately 0.8mm for the receptacle and its lip of the anchor socket, the base of the deflect pin can move relative to the anchor socket when the lateral component of the force exceeds approximately 5N (Newton Force). The deflect pin detaches from the anchor socket when the lateral component of the applied force to the mechanism exceeds approximately 20N during impact or a forceful handling. The mechanism keeps helmet parts in place in the absence of an impact force during normal use when the helmet is worn. These force thresholds can vary if several mechanisms hold parts and need to be considered when designing the passive deflection-sensitive mechanism according to the disclosed invention.

[0032] As the lateral component of the force exceeds the first threshold, the shaft bends, and the base of the deflect pin moves finitely relative to the anchor socket. When the force increases further, the deflect pin detaches from the anchor socket, allowing the parts attached by the deflect pin and the anchor socket to decouple and move relative to each other. The detachment of the deflect pin from the anchor socket during impact allows certain parts of the helmet to move (translationally, rotationally or a combination of both), which can enhance the protection of the head against head injury and concussion.

[0033] The deflection described herein represents controlled bending of the shaft, which allows limited translational and rotational displacement of the connected parts relative to each other before detachment. This bending deflection occurs as the deflect pin bends elastically or plastically under the lateral component of the impact force, while any shear deformation within the mechanism or between the connected parts that is caused by the lateral force remains negligible. The amount of this bending are influenced by the geometry and dimensions of the deflect pin, the material properties of the deflect pin, and the spacing between the deflect pin and the anchor socket.

[0034] In the same way, the proposed invention can be used in any other applications that require the mechanism to fail by decoupling under a certain amount of force.

[0035] In conventional snap lock assemblies, after attaching the male snap fastener to the female retainer, the base of the male snap fastener stays very close to the receptacle of the female retainer. This proximity is paramount for creating a strong attachment, minimizes the potential deflection of the shaft, and requires a relatively high amount of lateral force to cause the attachment to fail and detach. In most cases, unintended detachment by lateral force results in temporary or permanent deformation of the conventional female retainer or the male snap fastener. In snap lock assemblies, the male snap fastener is designed to withstand the anticipated range of lateral forces it normally receives without failure due to deflection of its shaft and deformation.

[0036] However, unlike conventional snap-lock assemblies, in a passive deflection-sensitive mechanism, it is important to design the mechanism so that the distance between the base of the deflect pin and the receptacle of the anchor socket is at least twice the thickness of the deflect pin's shaft. This distance is essential to allow the receptacle to exert the lateral component of the force received by the mechanism on the upper part of the shaft (closer to the head of the deflect pin), creating sufficient moment of force to deflect the shaft. If the receptacle of the anchor socket engages the shaft of the deflect pin close to its base, the mechanism will not deflect and decouple as expected. Therefore, parts equipped with a passive deflection- sensitive mechanism should be designed such that, when the parts are attached, the minimum distance between the receptacle of the anchor socket and the base of the deflect pin is twice the diameter of the shaft.

[0037] To allow the deflection of the shaft of the deflect pin to take place, the shaft length needs to be at least three times the thickness of the shaft. If the shaft cross-section is circular, the diameter of the shaft can be considered as the thickness of the shaft. If the cross-section of the shaft is not circular, an equivalent diameter is defined, which is the diameter of a circle with an area equal to the area of the cross-section of the shaft with a non-circular cross-section.

[0038] Equivalent diameter (De) is calculated using the following equation: De = SQRT (4 x A / pi); wherein SQRT is square root; wherein A is the area of the shaft with a noncircular cross-section; wherein Pi is 3.14.

[0039] If the thickness of the shaft varies along its length, the smallest diameter or smallest equivalent diameter should be regarded as the shaft’s thickness.

[0040] In an embodiment, the amount of relative movement of the deflect pin and the anchor socket under an applied force prior to detaching is defined by the length of the shaft, shaft thickness, distance of the base of the deflect pin from the receptacle of the anchor socket, and the material used for the mechanism.

[0041] In an embodiment, the shaft of the deflect pin includes one or more protrusions under its head. These protrusions can help adjust the tightness of the attachment of the mechanism and reduce unwanted play between the attached parts.

[0042] In an embodiment, the shaft of the deflect pin includes one or more protrusions, or raised areas under its head to help hold the deflect pin during the process of embedding it in an object such as a helmet or its components. For example, the shaft can include one or more disc- shaped protrusions with the same diameter as the head of the deflect pin to help hold the deflect pin in place during the manufacturing process, such as the foaming process of a helmet or helmet components.

[0043] In an embodiment, the shaft of the deflect pin includes protrusions under its head to allow adjustments of the distance between the two or more objects attached by the mechanisms. In some applications, such as helmets, the deflect pin and / or anchor socket are partially or entirely embedded in foam. Having protrusions on the shaft under the head of the deflect pin allows the two objects to be attached snugly, using the protrusions as multiple engagement points with the anchor socket while holding the attaching objects.

[0044] In an embodiment, the protrusion of the shaft can be designed such that the protrusion distance from the head of the deflect pin is similar to or slightly more than the thickness of the receptacle of the anchor socket. Such a design reduces the play between the two parts attached by the anchor socket and the deflect pin.

[0045] In an embodiment, the protrusions of the shaft can be designed such that the distance between every two juxtaposed protrusions is similar to or slightly more than the thickness of the receptacle of the anchor socket. Such a design reduces the play between the two parts attached by the anchor socket and the deflect pin, creates multiple engagement points between the deflect pin and the anchor socket, and finetunes the tightness of the mechanism.

[0046] In an embodiment, the deflect pin is partially embedded or recessed in a part to ensure the distance between the base of the deflect pin and the receptacle of the anchor socket is at least twice the diameter of the deflect pin's shaft when the parts are attached.

[0047] In an embodiment, the anchor socket is partially embedded or recessed in a part to ensure the distance between the base of the deflect pin and the receptacle of the anchor socket is at least twice the diameter of the deflect pin's shaft when the parts are attached.

[0048] In an embodiment, the deflect pin and the anchor socket are partially embedded or recessed in the attaching parts to ensure the distance between the base of the deflect pin and the receptacle of the anchor socket is at least twice the diameter of the deflect pin's shaft when the parts are attached.

[0049] In an embodiment, two or more objects are attached using the mechanism such that the deflect pin is part of one of the said objects, and its shaft is not rigidly constrained to limit the desired deflection of the shaft when force is applied to the mechanism. If the material used for the part in which the deflect pin is partially embedded is relatively hard, the area around the shaft must be partially cleared or hollowed. This allows the shaft to deflect as designed when a force applied to it exceeds a certain threshold. If the material used for the part in which the deflect pin is embedded is relatively soft and doesn’t hinder shaft motion for the range of force it is designed for, the shaft can be partially embedded in the material. For example, a thermoplastic nylon deflect pin can be partially embedded in expanded polystyrene (EPS) or any other shock-absorbing materials that are softer than the material used for the shaft of the deflect pin. Since EPS is relatively soft compared to conventional thermoplastics such as nylon used in the shaft of the mechanism, the EPS foam can partially fill the area around the shaft. However, if the helmet parts comprise harder materials such as polycarbonate (PC), it is important to ensure the PC used in the helmet part does not constrain the deflection of the shaft of the deflect pin when force is applied to the mechanism.

[0050] Another example is when a plastic deflect pin is placed or partially embedded in a metal part. In such a condition, the area around the shaft must be kept empty, with the hollow area diameter being at least twice the diameter of the shaft to avoid rigidly constraining the deflection of the shaft of the deflect pin when force is applied to the mechanism.

[0051] In an embodiment, at least an element of the disclosed mechanism comprises a material suitable for injection molding or additive manufacturing, including but not limited to thermoplastics such as polypropylene (PP), polyethylene (PE), acrylonitrile butadiene styrene (ABS), polystyrene (PS), polyvinyl chloride (PVC), polycarbonate (PC), and nylon (polyamide, PA), or a combination thereof.

[0052] In an embodiment, at least an element of the disclosed mechanism comprises thermoplastic elastomers (TPE) or thermosetting plastics, including epoxy, phenolic, urea-formaldehyde, or melamine-formaldehyde, or a combination thereof. In some embodiments, flexible materials like silicone may also be used for the elements in the said mechanism that require enhanced flexibility or heat resistance, or a combination thereof.

[0053] In an embodiment, at least an element of the disclosed mechanism can comprise metal such as steel, aluminum, copper, bronze, titanium, gold, silver, or composite, ceramics, or a combination thereof.

[0054] In one embodiment, the deflect pin and the anchor socket can be connected to each other by a string or wire of a desired length. The string or wire functions as a safetytether that prevents the parts, after decoupling, from being lost and ensures that they remain in proximity to each other.

[0055] In an embodiment, the thickness of the receptacle of the anchor socket is chosen to facilitate the release of the deflect pin when the force applied to the mechanism exceeds a certain threshold. The thickness of the receptacle, particularly the lip of it, can also play a role in the detachment of the deflect pin from the anchor socket. To fine-tune the force that allows detachment of the deflect pin from the anchor socket, it is possible to adjust the thickness of the receptacle of the anchor socket accordingly.

[0056] In an embodiment, the shaft thickness immediately next to the head of the deflect pin is tapered, such that the thickness of the shaft increases as the shaft approaches the head. The tapering of the shaft creates a self-tightening system for the mechanism and reduces the play between the two parts attached by the mechanism, as it encourages the shaft to go deeper into the anchor socket.

[0057] In an embodiment, the base of the deflect pin comprises holes or openings. These holes or openings can improve the flexibility of the base and consequently enhance the overall deflection of the deflect pin at its bottom where it attaches to the base, reducing the chance of the shaft being snapped off from its base when force is applied to the mechanism. Particularly, when a high-speed impact force is applied to the mechanism, having holes and openings in the base significantly improves the durability of the shaft and prevents it from being snapped off. Additionally, having holes and openings can improve the anchoring of the deflect pin when embedded in an object made of foam. Furthermore, having holes and openings in the base of the deflect pin reduces its weight, making the mechanism use less material and be more environmentally conscious.

[0058] In an embodiment, having the holes or openings in the base can be used for attaching the deflect pin to an object using conventional attachment means such as screws, rivets, adhesive, or other attachment methods known in various industries.

[0059] In an embodiment, the base of the deflect pin comprises anchoring arms to improve the anchoring of the deflect pin in the object or part it is partially embedded in. The arms can be in various forms and shapes such as T-shape, star, circular, or any free shape designs to improve the anchoring of the deflect pin. Adding arms to the base of the deflect pin is helpful for objects made of foam, such as helmets, where the deflection-sensitive mechanisms are placed in the mold prior to foaming to partially embed the mechanisms in the foam. This is also useful for objects that are not very hard and solid, such as shock-absorbing materials. If the objects the mechanism is attached to are relatively hard, such arms may not be needed. The same type of arms can also be implemented to improve the attachment of the anchor socket.

[0060] In an embodiment, the deflect pin and / or the anchor socket are attached to an object using any known attachment means in the industry, such as adhesive, co-molding (partially embedding in a part during molding), sewing, rivets, bolts, screws, heat seal, welding, clamps, hook and loop (Velcro), to name a few.

[0061] In an embodiment, when the lateral component of the applied force to the mechanism exceeds a certain threshold, the base of the deflect pin experiences a finite movement relative to the anchor socket. This threshold for bicycle helmet applications is not high and can be triggered with low-speed impacts or force applied manually. However, when a force is generated by medium to high-speed impacts, the base of the deflect pin moves further, and the deflect pin decouples or detaches from the anchor socket, allowing the parts attached to the deflect pin and anchor socket to move as needed to enhance the protection of the head against injury caused by rotational and linear forces.

[0062] According to research studies, the movement required by the helmet parts to enhance head protection during impact is less than 14 mm. Despite being small, such movements play a crucial role in reducing rotational and linear forces applied to the head during impact, thereby mitigating the risk of head injury and concussion. The mechanism is frangible and absorb only a negligible amount of force or impact energy by its deflection, deformation, or detachment. However, it plays an important role in allowing the parts to move when force exceeds a threshold to improve head protection. The same mechanism can be used in other applications that require parts to move or detach when the applied force to the parts exceeds a certain threshold.

[0063] In an embodiment, the mechanism as defined in the disclosed invention is frangible and absorb only a negligible amount of the energy of the applied force or impact to the mechanism or the objects the mechanism is attaching together. The role of the mechanism is to attach parts together and allow relative movement between the parts by deflection when the force applied to the parts exceeds a first threshold. When the force exceeds a higher second threshold, the parts can move further and detach from each other. The said force thresholds are defined based on the size, material, and configuration of the mechanism, the direction of the applied force to the said mechanism, the weight of the parts attached by the mechanism, and the application mechanism was used for.

[0064] The passive deflection-sensitive mechanism can be used for any applications requiring parts to move relative to each other when the applied force to the mechanism exceeds a first threshold and moves further and decouple when the applied force exceeds a second threshold. Some of the applications of the proposed mechanism include, but are not limited to, parts in safety devices, safety equipment, safety wearables, triggering devices, transportation vehicles, projectiles, clothing, construction, marine, sports gear, electronics, and robotics.

[0065] In an embodiment, the area around the shaft of the deflect pin is partially or entirely emptied to allow the shaft to deflect when the lateral component of the force applied to the mechanism exceeds a certain threshold. Having an area around the shaft emptied or recessed helps the shaft to deflect as needed for the application and allows relative movement or detachment of the deflect pin from the anchor socket depending on the amount of force applied to the mechanism. The emptied area around the shaft must have a minimum diameter of twice the shaft diameter, depending on the application. The empty space can be imagined as a hollow cylinder around the shaft. The larger the diameter of the hollow cylinder, the more freedom the shaft has for deflection. The hollow volume around the shaft can have any other shapes as long as it reduces the constraints on the deflection of the shaft.

[0066] In an embodiment, the area around the shaft of the deflect pin is partially or entirely filled with relatively soft material that still allows the deflection of the shaft of the deflect pin when the lateral component of the force applied to the mechanism exceeds a certain threshold. For instance, for helmet applications, the deflect pin can be partially embedded in a shock- absorbing foam that the helmet component is made of. The foam hardness compared to the thermoplastic used for making the mechanism is relatively low, and the shaft can deflect by deforming the foam around the shaft when the impact force applied to the helmet exceeds a certain threshold. The deflection can result in certain parts of the helmet moving relative to the other parts, and if the force increases further, the base of the deflect pin moves further, and the deflect pin decouples from the anchor socket. Consequently, the parts attached by the said mechanism can move relative to each other or detach from each other depending on the force magnitude and direction.

[0067] In an embodiment, the deflect pin is attached to a portion of the shock-absorbing material of the helmet and the anchor socket is attached to another portion of the shock-absorbing material of the helmet. During impact, the lateral force allows the deflect pin to move and detach from the anchor socket and allowing the two portions of the shock- absorbing materials to move relative to each other and therefore reduce the rotational and linear forces applied to the head during impact.

[0068] In one embodiment, one or more passive deflection- sensitive mechanisms are used to attach the shock-absorbing liner facing the wearer’s head to the shock- absorbing liner facing away from the wearer’s head.

[0069] In an embodiment, one or more passive deflection- sensitive mechanisms attach the fitting padding that are facing the wearer’ s head to the rest of the helmet, and during impact the mechanism allows the movement and detachment of the padding relative to the rest of the helmet.

[0070] In one embodiment, the passive deflection- sensitive mechanism can attach the outer shell of a helmet, which may be made of materials such as ABS or PC, to the rest of the shock- absorbing liner of the helmet. For example, the anchor socket can be embedded in the shock- absorbing liner, and the deflect pin, inserted through a hole in the outer shell, can attach the outer shell to the anchor socket.

[0071] In an embodiment, the outer shell of the helmet can be divided into multiple parts and each part is attached with one or more deflection-sensitive mechanisms to the rest of the shock- absorbing liner of the helmet. When the outer shell of helmet impacts an obstacle, the shell can move or detach from the rest of the helmet to decouple the impact force from the helmet and reduce the rotational and linear forces to the wearer’ s head.

[0072] In one embodiment, the shaft of the deflect pin is designed with stress-concentration points to promote failure under lateral forces by deflecting or snapping off the deflect pin at these points. Such a design may use a shaft length shorter than three times the shaft’s diameter, while still adhering to the principles defined in this invention, which is allowing parts to move when the lateral force component exceeds a specified threshold. For example, the shaft may have a smaller diameter at certain locations and a larger diameter at others. These smaller diameters create stress-concentration points that can lead to deflection or snapping of the shaft at these locations.

[0073] In one embodiment, the mechanism permits relative motion between the attached parts by deflection of the shaft of the deflect pin without allowing the detachment of the deflect pin from the anchor socket for the anticipated range of forces the mechanism is engineered to withstand.

[0074] In one embodiment, the mechanism comprises two or more materials. For example, the mechanism is made of nylon and silicone rubber.

[0075] In one embodiment, the deflect pin is composed of two or more materials. For example, it can be made partially of nylon and partially of silicone rubber.

[0076] In one embodiment, the anchor socket is composed of two or more materials. For example, it can be made partially of nylon and partially of silicone rubber.

[0077] In one embodiment, the portion of the shaft that connects to the base of the deflect pin is made of an elastic material. This design allows the shaft to deflect more effectively and elongate further before detaching from the anchor socket. Such elongation enables the attached parts to move relative to each other more significantly prior to the detachment of the deflect pin from the anchor socket. For example, a portion of the deflect pin can be made from nylon, while another portion of the deflect pin can be composed of silicone rubber.

[0078] In one embodiment, the head and most of the shaft of the deflect pin are made from a thermoplastic material, such as nylon, while the bottom of the shaft, where it connectsto the base, is partially or entirely composed of a rubber-like material, such as silicone rubber. This design enhances the mechanism’s ability to deflect and elongate before the deflect pin detaches from the anchor socket.

[0079] In one embodiment, consistent with the previous two embodiments, the head of the shaft is designed to lock within the anchor socket, and the mechanism permits relative motion between the attached parts without detachment within the anticipated force range.

[0080] In one embodiment, the anchor socket design is customized and is formed as a built- in component of another body that is attached by the deflect pin. For example, in a helmet, the outer shell of the helmet can comprise one or more holes that function as the anchor socket, and the deflect pin can be attached to the outer shell by engaging with the holes in the outer shell.

[0081] [Fig.l] show three views of the deflect pin 100 of the mechanism according to an embodiment in the disclosed invention. Part A of [Fig.l] shows the isometric view of the deflect pin 100 of the mechanism that consists of a head 101 and tip 102, long shaft 103, and base 104. The base 104 can comprise holes and openings 106 and anchoring arms 105. The shaft 103 can comprise protrusion 108 in the form of a disc or other shapes around the shaft 103. Part B of [Fig.l] depicts the side view of the deflect pin 100 and includes head 101 and its tip 102, shaft 103, base 104, anchoring arms 105, and protrusion 108 on the shaft 103. Part C of [Fig.l] shows the top view of the disclosed deflect pin 100 that consists of a head 101 and tip 102 (now shown), long shaft 103 (not shown), and base 104. The base 104 can comprise holes and openings 106 and anchoring arms 105. As shown in Parts A and B of [Fig.l] , the shaft 103 of the deflect pin 100 can have a tapering area 107 where the shaft 103 approaches the head 101. The tapering 107 helps reduce the play of the parts attached by the deflect pin 100 and an anchor socket (not shown in the figure) as a self-tightening mechanism. Anchoring arms 105 can improve the anchoring of the deflect pin 100 in the material it is embedded in. Holes and openings 106 can improve the flexibility of the base 104 and consequently reduce the chance of the shaft 103 being snapped off when force is applied to the deflect pin 100. In addition, having holes and openings 106 can a) further fortify the anchoring of the deflect pin 100 when embedded in an object, b) reduce its overall weight, and c) be used as a means for attaching the base 104 to an object. The head 101 can have any shapes and form that are available in prior art for the head of a pin.

[0082] [Fig.2] show three views of the anchor socket 200 of the mechanism according to an embodiment in the disclosed invention. Part A of [Fig.2] shows the isometric view of the anchor socket 200 that consists of receptacle 201 and its lips 203, opening 204, supporting arms 202, anchoring base 205, and cavity 206 that accommodates the head101 and a portion of the shaft 103 of the deflect pin 100. In some configurations, the cavity 206 can also accommodate the protrusion 108. Part B of [Fig.2] shows the side view of anchor socket 200, with visible parts being the receptacle 201, supporting arms 202, cavity 206, and the anchoring base 205. Part C of [Fig.2] shows the top view of the anchor socket 200 and consists of receptacle 201 and its lips 203, opening 204, supporting arms 202, anchoring base 205, and cavity 206 that accommodates the head 101 and a portion of the shaft 103 of the deflect pin 100. The opening 204 can have any shape or form depending on the application and the shape of the head 101 of the deflect pin 100. The head 101 can have any shape or form depending on the shape of the opening 204 and the application.

[0083] The anchor socket 200 can also influence the amount of force required to trigger detachment of the deflect pin 100 from the anchor socket 200. The thickness and shape of receptacle 201 and its lips 203 directly affects the amount of force needed to both assemble and disassemble the deflect pin 100 from the anchor socket 200. For example, our research study showed that the receptacle 201 and its lips 203 thickness for a bicycle helmet should be approximately between 0.6mm to 1mm when nylon thermoplastic is used for the anchor socket 200. This range of thickness allows the parts attached by the deflect pin 100 and anchor socket 200 to remain in place while wearing a helmet, and to detach when impact forces with relatively large rotational forces are applied to the helmet. The detachment of the parts and their movement can considerably reduce the risk of head trauma. According to research studies, the relative movement required during impact to enhance head protection is normally less than 14mm. Although such a movement seems small, it happens in a very short time (approximately 7 to 15 milliseconds), and it can significantly reduce rotational and linear acceleration of the brain during impact, which are known to be key factors behind head injury and concussion.

[0084] [Fig.3] shows the side view of component A 300 attached to component B 301 by means of the anchor socket 304 and the deflect pin 305, both partially embedded in component A and component B, respectively. The anchor socket 304 comprises receptacle 311 and its lip (not shown), supporting arms 313, anchoring base 312, cavity 314, and opening (not shown), which are mostly embedded in material 302 of component A 300. The deflect pin 305 comprises the head 310, shaft 306, base 308, and anchoring arms 309. The deflect pin 305 is partially embedded in material 303 of component B 301, and the recessed area 307 is considered to help with the deflection of shaft 306 when the lateral component of a force applied to component A 300 and / or component B 301 exceeds a certain threshold.

[0085] If the material 303 is soft compared to the material used for making the deflect pin 305, the recessed area 307 can be reduced in volume. If harder material is used formaterial 303 compared to the material used for the deflect pin 305, then more of the material 303 needs to be removed around the shaft 306 and the recessed area 307 must be increased in volume.

[0086] In an embodiment, component A 300 and component B 301 are enclosed inside outer material 316 and outer material 317, respectively. Outer materials 316 and 317 can be the same as material 302 and material 303, respectively.

[0087] In an embodiment, outer materials 316 or 317 are different from materials 302 or 303, respectively. The outer materials 316 or 317 can be made of hard materials such as PC, ABS, Kevlar, metal, or other known hard materials in various industries. For instance, for helmet applications, the outer materials 316 or 317 can be made of PC while materials 302 or 303 are made of a shock-absorbing foam such as EPS.

[0088] In an embodiment, the outer material 317 is made of PC, ABS, or other hard materials while material 303 is made of shock- absorbing foam such as EPS or expanded polypropylene (EPP), such that the area 318 of component B 301 is not covered with outer material 317 to allow the shaft 306 to move when the lateral component of impact (perpendicular to the shaft 306 axial direction) exceeds a certain threshold. Such an arrangement allows finite movement of component A 300 relative to component B 301 when the applied force exceeds a certain threshold. The absence of a relatively hard outer material 317 in area 318 facilitates the deflection of the shaft 306. This deflection, in turn, aids the movement and detachment of the deflect pin 305 from the anchor socket 304 when the lateral component of the force exceeds a certain threshold.

[0089] In an embodiment, the recessed area 307 has a diameter that is at least twice the diameter of shaft 306. For example, for bicycle helmets, our study showed that the suitable diameter of the recessed area 307 is approximately four times or higher than the diameter of shaft 306. Material 303 can be made of relatively soft material such as EPS or EPP compared to the injection-molded deflect pin 305, which is normally made of a thermoplastic such as nylon. This allows the shaft 306 to easily deform material 303 around the shaft 306 and deflect when lateral force is applied to the deflect pin 305. The recessed area 307 can have any other shapes or forms, as long as it does not constrain the movement of shaft 306.

[0090] In an embodiment, the deflect pin 305 and the anchor socket 304 are partially embedded in component B 301 and component A 300, respectively, to make sure the distance between the base 308 and receptacle 311 is at least twice the diameter of the shaft 306. This distance allows the receptacle 311 to transfer the lateral force received by the anchor socket 304 to the shaft 306 to create sufficient moment of force in the shaft 306 relative to base 308 to deflect and cause decoupling of the deflect pin 305 from the anchor socket 304. For instance, for bicycle helmets, our study showed thatthe suitable distance between the base 308 and receptacle 311 is approximately 3.5 times the diameter of the shaft 306.

[0091] In an embodiment, the deflect pin 305 is recessed and partially embedded in component B 301 to make sure the distance between the base 308 and receptacle 311 is at least twice the diameter of the shaft 306.

[0092] As shown in [Fig.3] , protrusion 315 is placed under the head 310 of the deflect pin 305. Protrusion 315 allows for multiple engagement points for the deflect pin 305. Having multiple engagement points by means of having one or more protrusions 315 allows reducing the potential play between the deflect pin 305 and the anchor socket304. If engagement of the head 310 does not result in a tight enough attachment, it is possible to push the deflect pin 305 further into cavity 314 to have less play and a more tightened attachment. This is helpful in designs that may not be very accurate, and the location of the deflect pin 305 and anchor socket 304 can be slightly inaccurate or, due to overuse of the mechanism, the deflect pin 305 or anchor socket 304 may have been dislocated or permanently pushed in.

[0093] In addition, having protrusion 315 can act as support, holding the deflect pin 305 in place during the process of manufacturing the component that the deflect pin 305 is partially embedded in. Without protrusion 315, the only contact point of the deflect pin 305 and the mold it is inserted into is its head 310. This can result in unwanted movement of the deflect pin 305 during manufacturing the component that the deflect pin 305 is partially embedded in.

[0094] An example of this is during foaming a helmet or helmet parts, when foam beads are introduced into the mold, the pressurized flow of beads can dislocate the deflect pin305. Particularly, having a long shaft 306 makes the deflect pin 305 more unstable and wobblier during foaming. Having protrusion 315 significantly improves its stability in the mold during foaming a helmet or its parts.

[0095] In an embodiment, the protrusion 315 can be designed such that the distance from the head 310 to the protrusion 315 is similar to or slightly more than the thickness of the receptacle 311. Such a design reduces the play between component A 300 and component B 301 attached by the anchor socket 304 and the deflect pin 305.

[0096] Part A of [Fig.4] shows a conventional male snap fastener 400 used for various applications. The conventional male snap fastener 400 comprises a head 401, shaft 402, and a base 403. In the conventional male snap fastener 400, the height of the shaft 402 (Hl) is approximately equal to the diameter of the conventional deflect pin 400; meaning that the ratio of the height (Hl) to the diameter (DI) is approximately 1. Part B of [Fig.4] shows an example for the deflect pin 410 made according to the disclosed invention that comprises head 411, shaft 412, base 413, anchoring arms 414, and protrusion 415. The deflect pin 410 height (H2) is approximately four timesthe diameter (D2) of the shaft 412; meaning that the ratio of the height (H2) to the diameter (D2) is approximately four. Having a ratio of four allows the shaft to deflect. However, it is paramount to make sure the receptacle of the corresponding anchor socket is as close as possible to the head 411 to generate the required moment of force for the deflection. This deflection occurs when the lateral component of a force applied to the deflect pin 410 exceeds a certain threshold. As a result, there is relative movement or detachment of the deflect pin 410 and its corresponding anchor socket. Such deflection is not intended to happen for the conventional male snap fastener 400 under the amount of force they are designed to operate.

[0097] [Fig-5] illustrates helmet 500 that is worn on the head 501 and it comprises a shock-absorbing liner 505 and one or more pieces of an outer shell 504 that are partially or entirely covering the shock- absorbing liner 505 and are attached to the shock-absorbing liner 505 by means of a deflect pin 502 and an anchor socket 503. The anchor socket 503 is embedded in the shock-absorbing liner 505. The passive deflection-sensitive mechanism that includes the deflect pin 502 and the anchor socket503 holds the outer shell 504 in place during normal use. In one embodiment, the outer shell 504 includes holes allowing the deflect pin 502 to pass through the holes and attach to the anchor socket 503. The helmet 500 can include padding material 507 that is attached to the shock-absorbing liner 505 by an attachment means 508 such as a hook-and-loop fastener or other fasteners commonly used in the helmet industry. When the helmet 500 impacts an obstacle at an angle, a lateral force is applied to one or more of the outer shell 504. When the lateral force exceeds a first threshold, the outer shell504 can move finitely relative to the shock-absorbing liner 505 by means of deflection of the deflect pin 502. When the lateral force exceeds a higher, second threshold, the deflect pin 502 detaches from the anchor socket 503 and one or more pieces of the outer shell 504 detach from the helmet 500. The detachment of the outer shell 504 decouples the impact force from the helmet 500 and can reduce rotational and linear forces applied to the head 501. The shock- absorbing liner 505 can include a recession 509 to facilitate the movement of the shaft of the deflect pin 502.

[0098] In certain embodiments, friction between the surface of the outer shell 504 facing the head 501 and the surface 506 of the shock- absorbing liner 505 may be reduced. This reduction in friction can be achieved by applying surface treatments to either or both surfaces, such as the application of a lubricant, including silicone grease or Teflon, to one or both surfaces. These measures reduce resistance to relative sliding between the surfaces during impact.

[0099] In one embodiment, the outer shell 504 can be attached to the shock-absorbing liner505 by means of a deflect pin 510 without the use of an anchor socket similar to theanchor socket 503. In such a design, the outer shell 504 includes one or more holes that function as receptacles equivalent to the anchor socket 503.

[0100] [Fig.6] shows helmet 600 that is worn on the head 601. The helmet 600 comprises an outer shell 602 that is attached to a base shock- absorbing liner 603 by means of a mechanical or chemical fastener such as co-moulding, adhesive, rivets, screws, or hook-and-loop fasteners. One or more modular shock- absorbing liners 606 is attached to the base shock- absorbing liner 603 by means of passive deflection- sensitive mechanisms that comprise a deflect pin 604 and an anchor socket 605. The deflect pin 604 can be partially embedded in the base shock- absorbing liner 603 or partially embedded in the modular shock- absorbing liner 606. The anchor socket 605 can be embedded in the base shock- absorbing liner 603 or embedded in the modular shockabsorbing liner 606. The helmet 600 can also comprise padding material 607 that is attached to the modular shock- absorbing liner 606 by an attachment means 608 such as a hook-and-loop fastener, or other fasteners commonly used in the helmet industry. When an applied impact force to the outer shell 602 of the helmet 600 exceeds a first threshold, the modular shock-absorbing liner 606 moves finitely relative to the base shock-absorbing liner 603. When an impact force exceeds a higher, second threshold, the deflect pin 604 detaches from the anchor socket 605 and the modular shockabsorbing liner 606 and the padding material 607 and the head 601 move relative to the base shock- absorbing liner 603, thereby reducing the rotational and linear forces applied to the head 601.

[0101] To avoid cluttering the figures and to focus on the novel aspects of the present invention, common helmet components such as a chin strap, neck retention system, or other conventional fastening and adjustment systems are not shown. These components are well known in the art, and are part of the prior art, and their omission from the figures is solely for clarity of illustration. The disclosed invention can be implemented in helmets that include such conventional components without departing from the scope of the present disclosure.

[0102] While illustrative embodiments have been shown and described, it will be appreciated that various changes and modifications can be made without departing from the scope of the invention. The detailed description provided above in connection with the accompanying figures, where like numerals reference like elements, is intended to describe exemplary embodiments of the claimed subject matter and is not intended to represent the only embodiments. Any reference to a direction is specific to the figures and serves solely to clarify the explanation, without limiting the actual use or orientation of the invention. The illustrated examples are not intended to be exhaustive or to limit the invention to the precise forms shown.

Claims

Claims

1. A passive deflection-sensitive mechanism for attaching specific parts of a helmet, comprising a deflect pin and an anchor socket; wherein the deflect pin includes a head, shaft, and base; wherein the anchor socket includes a receptacle with lips and a cavity; wherein the head of the deflect pin is configured to lock into the receptacle of the anchor socket; wherein the length of the deflect pin’s shaft is at least three times the minimum diameter or equivalent diameter of the shaft; wherein the mechanism is frangible and absorbs only a negligible amount of impact energy due to deflection and detachment of the deflect pin from the anchor socket during impact to the helmet, failing solely by detachment, the detachment occurring under lateral forces typically encountered by a helmet during impact; wherein the shaft deflects when the lateral component of an applied force to the mechanism exceeds a first threshold, allowing limited relative translational and rotational movement between the parts connected by the mechanism; wherein the shaft further deflects, and the deflect pin detaches from the anchor socket when the lateral component of the applied force exceeds a higher second threshold, causing the attached parts to detach and move relative to each other and reduce rotational and linear forces applied to the head.

2. The passive deflection- sensitive mechanism of Claim 1, wherein the mechanism is configured in the parts it is attaching such that the distance of the base of the deflect pin from the receptacle of the anchor socket is at least twice the minimum diameter of the shaft of the deflect pin.

3. The passive deflection- sensitive mechanism of Claim 1, wherein one or more said mechanisms hold the connected parts securely in place during normal use in the absence of impact forces.

4. The passive deflection- sensitive mechanism of Claim 1, wherein the deflection of the deflect pin represents controlled bending that allows limited translational and rotational displacement of the connected parts relative to each other before detachment.

5. The passive deflection- sensitive mechanism of Claim 1, wherein the shaft of the deflect pin comprises one or more protrusionsbeneath its head to create multiple engagement points for the deflect pin when attaching to the anchor socket.

6. The passive deflection- sensitive mechanism of Claim 1, wherein the shaft of the deflect pin comprises one or more protrusions beneath its head to securely hold the deflect pin in place during the manufacturing of the part in which the deflect pin is partially embedded.

7. The passive deflection- sensitive mechanism of Claim 1, wherein the base of the deflect pin comprises holes or openings to improve the deflection and durability of the deflect pin when a force with a lateral component is applied to the mechanism.

8. The passive deflection- sensitive mechanism of Claim 1, wherein the base of the deflect pin comprises anchoring arms configured to enhance retention when the base is embedded in foam or other helmet materials.

9. The passive deflection- sensitive mechanism of Claim 1, wherein the amount of force required for detachment of the deflect pin from the anchor socket can be fine-tuned by varying the thickness of the receptacle and lips of the anchor socket and by adjusting the geometry and size of the head and shaft of the deflect pin.

10. The passive deflection- sensitive mechanism of Claim 1, wherein the helmet parts attached by the mechanism undergo finite movement in translational and rotational directions relative to each other when the lateral component of the applied force to the mechanism of the helmet exceeds a first threshold.

11. The passive deflection- sensitive mechanism of Claim 1, wherein the helmet parts attached by the mechanism decouple and move in translational and rotational directions relative to each other as whole bodies when the lateral component of the force applied to the mechanism exceeds a second, higher threshold.

12. The passive deflection- sensitive mechanism of Claim 1, wherein the mechanism is frangible and absorbs only a negligible amount of impact energy due to deflection, deformation, and detachment of the deflect pin from the anchor socket during impact to the helmet.

13. The passive deflection- sensitive mechanism of Claim 1, wherein the mechanism attaches one or more modular shock-absorbing liners positioned adjacent the head to a base shock-absorbingliner that is located farther from the head and secured to an outer shell and, when a lateral component of an applied impact force exceeds a first threshold, enables finite translational and rotational movement of the modular shock-absorbing liner(s) relative to the base shock-absorbing liner, and, when the lateral component exceeds a second, higher threshold, causes detachment of the modular liner or liners from the base shock- absorbing liner.

14. The passive deflection- sensitive mechanism of Claim 1, wherein the mechanism attaches one or more outer-shell pieces of a helmet to a shock- absorbing liner and, when subjected to lateral forces, enables finite translational and rotational movement of the outer-shell piece(s) relative to the liner at a first threshold and detachment at a higher, second threshold.

15. The passive deflection- sensitive mechanism of Claim 1, wherein the deflect pin bends elastically or plastically under the lateral component of the impact force while any shearing motion between the connected parts caused by the lateral force is negligible.

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