WO2025236148A1

WO2025236148A1 - A wearable device for reducing air drag and a method of manufacturing the same

Info

Publication number: WO2025236148A1
Application number: PCT/CN2024/092842
Authority: WO
Inventors: Yat Ming Calvin KU
Original assignee: Individual
Current assignee: Individual
Priority date: 2024-05-13
Filing date: 2024-05-13
Publication date: 2025-11-20
Anticipated expiration: 2026-11-13

Abstract

The invention provides a wearable device for reducing air drag. The wearable device comprises a body adapted to associate with a subject, the body comprising at least one inflatable chamber; wherein, when the inflatable chamber is in an inflated state, the body defines a streamlined exterior extending along a direction of airflow.

Description

A Wearable Device For Reducing Air Drag And A Method Of Manufacturing The Same

Field of the Invention

The invention relates to the field of aerodynamic. Particularly but not exclusively, the invention relates to a means for reducing air drag on a subject when moving in an airflow.

Background of the Invention

In various activities involving subjects in motion within dynamic airflows, such as cycling, driving, skiing, snowboarding, roller-skating, or the like, one primary factor limiting speed and stability of the ride is the drag force. Aerodynamic drag in cycling, for instance, consists of two components: friction drag (also known as surface drag or skin drag) and pressure drag (also known as form drag) . While friction drag can be reduced by the cyclist’s wearing of tight, smooth clothing and minimizing skin exposure; pressure drag primary arises from the interaction between the surrounding airflow and the cyclist’s body. As air flows over surface of the cyclist, it encounters resistance due to the shape and contours of the cyclist’s body. This results in the creation of regions with various pressure: regions of high pressure correspond to areas with slower airflow, while regions of low pressure are areas with faster airflow.

During cycling, the front portion of the cyclist’s body experiences significant static pressure. As the airflow progresses over and along the body surface, the flow undergoes an increased length along the cyclist's back, leading to a decrease in static pressure. This decrease in pressure gives rise to a negative pressure gradient. When airflow encounters a negative pressure gradient, it tends to separate from the body surface. Flow separation occurs when the airflow loses its attachment to the body and forms eddies or vortices, which disrupts the smooth passage of air and creates additional resistance in the form of pressure drag.

To minimize pressure drag, it is desirable to prevent or at least, delay flow separation, ideally pushing it as far rearward as possible, and promote laminar airflow near the body surface.

Various techniques have therefore been employed to reduce pressure drag and to enhance aerodynamic efficiency. For example, one common approach is to modify shapes of the vehicle by minimizing sharp edge, optimizing curvature and employing smooth contours. Additionally, aerodynamic coverings or enclosures, such as fairings and cowls, can be installed to vehicles and bicycles to streamline their shape and reduce drag. Furthermore, aerodynamic helmets have been designed to minimize turbulence and promote laminar airflow over the rider’s head.

There remains a need for an innovative solution which enables reduction of drag resistance in a manner which is simple and convenient.

Objects of the Invention

An object of the present invention is to provide a means for reducing aerodynamic drag.

Another object of the present invention is to mitigate or obviate to some degree one or more problems associated with known aerodynamic techniques, or at least to provide a useful alternative.

The above objects are met by the combination of features of the main claims; the sub-claims disclose further advantageous embodiments of the invention.

One skilled in the art will derive from the following description other objects of the invention. Therefore, the foregoing statements of object are not exhaustive and serve merely to illustrate some of the many objects of the present invention.

Summary of the Invention

In a first main aspect, the invention provides a wearable device for reducing air drag. The wearable device comprises a body adapted to associate with a subject. The body comprises at least one inflatable chamber, wherein, when the inflatable chamber is in an inflated state, the body defines a streamlined exterior extending along a direction of airflow.

In a second main aspect, the invention provides a method of manufacturing the wearable device for reducing air drag according to the first main aspect. The method comprises the steps of arranging at least one inflatable chamber at a body; wherein, when the inflatable chamber is in an inflated state, the body defines a streamlined exterior extending along a direction of airflow; arranging an air inlet at the body; wherein the air inlet is adapted to be in fluid communication with an interior of the inflatable chamber when the air inlet is arranged to be in open condition; and providing an associating means at the body for associating the body with a subject.

The summary of the invention does not necessarily disclose all the features essential for defining the invention; the invention may reside in a sub-combination of the disclosed features.

Brief Description of the Drawings

The foregoing and further features of the present invention will be apparent from the following description of preferred embodiments which are provided by way of example only in connection with the accompanying figure, of which:

Fig. 1 is a schematic diagram showing a concept of the wearable device for reducing drag according to the present invention;

Fig. 2 shows a side view of the embodiment of the wearable device of Fig. 1;

Fig. 3 is a schematic diagram showing another embodiment of the wearable device of the present invention in use;

Fig. 4 is a schematic diagram showing a further embodiment of the wearable device of the present invention in use;

Fig. 5 shows the embodiment of the wearable device of Fig. 4;

Fig. 6 shows a cross-sectional view of the embodiment of the wearable device of Fig. 5; and

Fig. 7 shows a top view of the embodiment of the wearable device of Fig. 5.

Description of Preferred Embodiments

The following description is of preferred embodiments by way of example only and without limitation to the combination of features necessary for carrying the invention into effect.

Reference in this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Moreover, various features are described which may be exhibited by some embodiments and not by others. Similarly, various requirements are described which may be requirements for some embodiments but not other embodiments.

Referring to Figs. 1 and 2, depicted are conceptual views showcasing the wearable device 10 for reducing aerodynamic drag, and specifically, pressure drag or form drag experienced by a moving subject. The present invention is designed to generally cover a wide range of activities involving various modes of transport, vehicles, or vessels, which may include, but are not limited to, bicycles, scooters, gliders, motorbikes, automobiles such as lorries and buses, skis, snowboards, roller-skates, roller-blades, aircrafts such as unmanned aerial vehicles (UAV) , watercrafts, or the like. In the context of the present invention, the term “subject” can be given a broad meaning to refer to subject users such as a rider, player, operator, or any individual operating the mode of transport, and the subject might as well be the mode of transport itself or a part or parts thereof. While cycling has been illustrated in the figures as an example, it should be noted that the present invention is applicable to any other sports or activities where users or players engage in movement in dynamic airflows, resulting in the generation of drag force.

In one embodiment, the wearable device 10 comprises a body 20 adapted to associate with the subject user which can be, as illustrated, a cyclist on a bicycle. The body 20 of the wearable device 10 preferably comprises at least one inflatable chamber 30 which, when being inflated to an inflated state, the body 20 defines a streamlined exterior which extends along or aligns with the direction of airflow, that is, in case of a forward movement of the bicycle, a relative backward movement of airflow. The term “streamline” or “streamlined” generally uses to describe a form that is configured by smooth and flowing contours, with minimal protrusions, sharp or abrupt edges to thereby to minimize resistance to fluid flow.

In one embodiment, the inflatable chamber 30 can be configured or provided within the body 20, i.e. with the body 20 encasing or housing the chamber 30. In another embodiment, the inflatable chamber 30 can be integrally formed with the body 20. In a further embodiment, the chamber 30 can be arranged at the body 20 through various means, including placement or attachment at the interior and/or exterior of the body 20.

In the context of the present invention, the term “associate” or “associated” is used in board term to encompass various modes of connection or association, which may include, but are not limited to, wearing and/or attaching through use of attaching means, as well as connection via any known types of connectors or linkages. In one embodiment, the association can be provided via an associating means 70 which may include one or more of a strap such as a back strap or a body strap, a belt, a button, a zipper, a clip, a lock, a hook and/or a fastener such as the Velcro fastener.

The body 20 is preferably constructed using light-weight, durable and flexible materials which facilitate expansion when the inflatable chamber 30 is inflated. Other preferred characteristics of the materials may include UV-resistance, water-repellence, chemical-resistance, and/or ease of cleaning and maintenance. In one embodiment, polymer materials such as but not limited to polyvinyl chloride (PVC) , thermoplastic polyurethane (TPU) , polyethylene (PE) , polyester such as polyethylene terephthalate (PET) , nylon-based fabrics are preferable materials as they are known for their suitability in outdoor applications.

In one embodiment, the body 20 preferably extends along a longitudinal axis defining a rear end and a front end of the body 20 when the inflatable chamber 30 is in the inflated state or in use. When providing the device 10 at the back of the user’s body, such as by means of wearing of the device 10 by a cyclist riding a bicycle, the longitudinal extension of the device body 20 serves to effectively extend the user’s body along the direction of the airflow, increasing the contact surface with the air thereby delaying air separation. This prolonged interaction between the airflow and the user’s body helps preventing the formation of vortices or turbulent wake behind the user and/or the bicycle, resulting in reduced drag and enhanced aerodynamic performance. In one embodiment, the degree of extension and thus the overall length of the body 20 can be adjustable by providing a varying degree of inflation at the inflatable chamber 30. By modifying the degree of inflation of the chamber 30, length of extension of the body 20 can be adjusted to accommodate different speed ranges for optimizing stability and efficiency. For example, with a higher degree of inflation at the chamber 30, a longer extension of the body 20 can be achieved which is preferrable for reducing pressure drag at a higher speed ride, and vice versa.

Preferably, when the inflatable chamber 30 is in the inflated state or in use, the device body 20 is configured to substantially taper towards the rear end of the body 20, as shown in the embodiments of Figs, 1, 2, 3 and 4 as examples. In one embodiment, the body 20 comprises an upper portion 40 profiled to taper towards the rear end of the body 20.More preferably, the upper portion 40 is configured to curve substantially downwardly towards the rear end of the body 20, such as as illustrated in Figs 1, 2 and 4. In one further embodiment, the body 20 comprises a lower portion 50 profiled to taper towards the rear end of the body 20. More preferably, the lower portion 50 is configured to curve substantially upwardly towards the rear end of the body 20, such as as illustrated in Figs. 1, 2, 3 and 4.

The tapered configuration towards the rear end of the device body 20 further assists in reducing air drag as the tapering of the body 20 leads to a gradually decrease in the cross-sectional area, which results in a reduction of pressure difference between the front end and the rear end of the body 20. More particularly, the downwardly curved upper portion 40 and/or the upwardly curved lower portion 50 of the body 20 further provide streamlined contours of the body 20, which helps to smoothen and streamline the airflow. The smooth airflow around the tapered rear end minimizes disruption and separation of airflow, thus reduces the formation of vortices and turbulent wake which are known to increase drag.

To facilitate extension of the device body 20, the inflatable chamber 30 preferably extends at least partially along the longitudinal length of the device body 20, and more preferably, extends over the length of the device body 20. As more clearly shown in Figs. 4 to 6, the inflatable chamber 30 may comprise a plurality of inflatable chambers 30, such as two vertically aligned chambers 30A and 30B, as shown in Fig. 6, although the chambers 30 can be provided in various configurations including arrangement with more than two chambers and/or different alignments, such as being horizontally aligned or sequential arrangement from one distal end to the other. In one embodiment, the body 20 may feature multiple inflatable chambers 30 which are releasable attachable at selective positions within the interior of the body 20. This facilitates the provision of additional expansions at selective positions and/or adjustment on the distribution of expansions within the body 20 to optimize stability and efficiency of the ride.

Preferably, one or more air inlets 32 can be arranged at the body 20 to allow fluid communication with the interior of the inflatable chamber 30, and particularly, to allow gaseous communication between the interior of the inflatable chamber 30 and the ambient air, when the air inlets are configured in an open condition. More preferably, the air inlet comprises a valve (not shown) such as a unidirectional valve to control air passage. For example, the valve can be configured to allow the flow of air, such as ram air generated during motion, to inflate the chamber 30 in one direction while preventing backflow of air in the opposite direction. Particularly, the valve is designed to open and allow airflow into the chamber when the pressure outside the chamber, i.e. the ram air pressure exceeds the pressure inside the chamber. The pressure gradient forces the valve to open, permitting air to enter the chamber 30; and once the air chamber is sufficiently inflated, the unidirectional valve automatically closes to prevent air from escaping or backflowing out of the chamber 30. This ensures that the chamber 30 remains inflated and maintains its desired pressure. In one embodiment, multiple air inlets equipped with different valves can be provided to allow adjustment of internal pressure at different travelling air speeds. This enables fine-tuning of the inflation level based on specific activity requirements. In one further embodiment, various inflating means can be adopted or applied to facilitate the inflation process, for example, the use of powered fans, manual pumps, or even a mouthpiece for orally blowing up the chamber 30, to allow flexibility and convenience to users. In yet a further embodiment, one or more inflatable chamber 30 can be fully or partially filled with additional volumetric components such as foams, cotton or similar materials which allows structural integrity to the inflated chamber 30 according to specific needs or desired performance.

The body 20 may preferably comprise opposing left side portion and right side portion on the lateral sides of the body 20 which extend between the rear end and the front end of the body 20. In one specific embodiment, one or more air directing means 60 can be arranged at the body 20 to further reduce vortices and thus air drag. The air directing means 60 can be provided in various configurations, including variation in sizes and shapes to meet specific requirements of the activity. In the embodiment as shown in Figs. 4, 5 and 7, for example, the air directing means 60 can be provided in the form of a pair of winglets arranged at the respective left side portion and right side portion of the body 20 to enhance aerodynamic performance thereby improving speed, stability and control of the ride.

Fig. 5 further illustrates a specific embodiment of the wearable device 10, which is designed to be worn at the back of a subject user. In this embodiment, the body 20 of the device 10 is adapted to associate with the user by positioning the front end of the body 20 to face the user’s back, that is, for the body 20 to extend rearwardly towards the rear end of the body 20. Particularly, the device 10 further comprises the associating means 70 for attaching or securing the body 20 to the user. The associating means 70 may encompass various forms which may include one or more of a strap like configurations such as a pair of backstraps, as shown in Fig. 5. Alternatively, the associating means 70 may comprise a body strap, a belt, a button, a zipper, a clip, a lock, a hook, a fastener such as the Velcro fastener and/or an adhesive. In yet another embodiment, the wearable device 10 may take the form of a wearable garment piece, such as a shirt, a vest, a jacket, a belt, a jumpsuit, etc. with the device body 20 permanently or releasable associated therewith, such as via connectors like zippers or buttons. In one embodiment, it is preferred that the device body 20 is releasable detachable from the associating means 70. This enables users to easily remove the body 20 after completing the activity, or for the purpose of storage and maintenance. A person skilled in the art would recognize that the associating means 70, which enables the wearable placement of the device 10 on the user, should not be restricted to the specific embodiments described or depicted. Instead, any known attaching or associating means capable of achieving the desired effect of positioning the device 10 on the user's body should be considered within the scope of the invention.

In one specific embodiment, the body 20 of the wearable device 10 is designed with a preferred range of dimensions to ensure optimal efficiency. The dimensions may comprise a length range of about 20 cm to about 700 cm, a height range of about 10 cm to about 460 cm, and a width range of about 5 cm to about 300 cm. More preferably, the body 20 may be proportioned with a preferred length to height ratio of about 2: 1 to about 5:1, and/or a preferred width to height ratio of about 1: 2 to about 1: 4 In one further embodiment, the inflatable chamber 30 is designed to have a preferred range of inflation of about 1 atm to about 2 atm.

In yet a further embodiment, the body 20 of the wearable device 10 may further comprise or be incorporated with one or more compartments designed for storage purposes. These compartments provide convenient space to securely store and carry personal belongings of the user during various activities.

In another aspect of the present invention, it is provided a method of manufacturing the wearable device 10 for reducing air drag as above described. The method comprises the steps of arranging at least one inflatable chamber 30 at the device body 20, and particularly, when the inflatable chamber 30 is in its inflated state, the body 20 defines a streamlined exterior extending along a direction of airflow. The step further comprises arranging an air inlet 32 at the body 20; wherein the air inlet 32 is adapted to be in fluid communication with an interior of the inflatable chamber 30 when the air inlet 32 is arranged to be in open condition. The method further includes the step of providing an associating means 70 at the body 20 for associating the device body 20 with the subject user.

The present invention is advantageous in that it provides a lightweight, flexible and customizable device for reducing air drag on user during sports or activities which involve movement in dynamic air. The device is easily wearable by the user, that is, can be easily and conveniently attachable on the user when needed, and be readily detachable from the user when the activity is finished. The device comprises inflatable chamber which, when inflated, creates streamlined contours on the device body to enhance aerodynamic performance of the user. On the other hand, when deflated, the device becomes compact for easy carry and storage. The invention has been proven to effectively reduce pressure drag by extending the user’s body line rearwardly in the airflow. The extension helps to avoid or delay air separation behind the user, resulting in improved stability and efficiency during movement within airflow. The level of extension of the device body is further customizable by the adjusting the inflation of the inflatable chamber, thereby allowing optimal performance in various cycling speed and wind speed conditions. The present invention therefore provides a versatile and convenient wearable device capable of effectively reducing air drag. Its simple structure facilitates easy manufacture at relatively low costs. As the device can be effortlessly applied by wearing it on the user’s body, this negates the need for any modifications, installations or alterations to the sports equipment or the vehicles. By minimizing air resistance, the device of the present invention empowers users to optimize their performance in diverse sporting or active scenarios.

The present description illustrates the principles of the present invention. It will thus be appreciated that those skilled in the art will be able to devise various arrangements that, although not explicitly described or shown herein, embody the principles of the invention and are included within its spirit and scope.

Moreover, all statements herein reciting principles, aspects, and embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future, i.e., any elements developed that perform the same function, regardless of structure.

While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only exemplary embodiments have been shown and described and do not limit the scope of the invention in any manner. It can be appreciated that any of the features described herein may be used with any embodiment. The illustrative embodiments are not exclusive of each other or of other embodiments not recited herein. Accordingly, the invention also provides embodiments that comprise combinations of one or more of the illustrative embodiments described above. Modifications and variations of the invention as herein set forth can be made without departing from the spirit and scope thereof, and, therefore, only such limitations should be imposed as are indicated by the appended claims.

In the claims hereof, any element expressed as a means for performing a specified function is intended to encompass any way of performing that function. The invention as defined by such claims resides in the fact that the functionalities provided by the various recited means are combined and brought together in the manner which the claims call for. It is thus regarded that any means that can provide those functionalities are equivalent to those shown herein.

In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art.

Claims

A wearable device for reducing air drag, comprising:

a body adapted to associate with a subject, the body comprises at least one inflatable chamber; wherein, when the inflatable chamber is in an inflated state, the body defines a streamlined exterior extending along a direction of airflow.
The wearable device according to claim 1, wherein the body extends along a longitudinal axis defining a rear end and a front end of the body when the inflatable chamber is in the inflated state.
The wearable device according to claim 2, wherein the body is configured to substantially taper towards the rear end of the body.
The wearable device according to claim 3, wherein the body comprises an upper portion profiled to taper towards the rear end of the body.
The wearable device according to claim 4, wherein the upper portion is configured to curve substantially downwardly towards the rear end of the body.
The wearable device according to claim 3, wherein the body comprises a lower portion profiled to taper towards the rear end of the body.
The wearable device according to claim 6, wherein the lower portion is configured to curve substantially upwardly towards the rear end of the body.
The wearable device according to claim 2, wherein the body comprises opposing left side portion and right side portion extending between the rear end and the front end of the body.
The wearable device according to claim 8, further comprising an air directing means arranged at the body.
The wearable device according to claim 9, wherein the air directing means comprises one or more winglets arranged transversal to one or more of the left side portion and the right side portion, respectively.
The wearable device according to claim 1, wherein the at least one inflatable chamber extends at least partially along a length of the body.
The wearable device according to claim 1, wherein the at least one inflatable chamber comprises a plurality of inflatable chambers.
The wearable device according to claim 1, further comprising at least one air inlet at the body configured to be in fluid communication with an interior of the inflatable chamber when the air inlet is in an open condition.
The wearable device according to claim 13, wherein the at least one air inlet comprises a valve to control air passage.
The wearable device according to claim 2, wherein, when in use, the body is adapted to associate with the subject at the front end of the body.
The wearable device according to claim 15, wherein, when in use, the front end of the body is positioned to face a back side of the subject.
The wearable device according to claim 1, further comprising an associating means for associating the body with the subject.
The wearable device according to claim 17, wherein the associating means comprises one or more of a strap, a belt, a button, a zipper, a clip, a lock, a hook, a fastener and/or an adhesive.
The wearable device according the claim 1, wherein the body further comprises one or more compartments.
A method of manufacturing the wearable device for reducing air drag according to claim 1, comprising the steps of:

arranging at least one inflatable chamber at a body; wherein, when the inflatable chamber is in an inflated state, the body defines a streamlined exterior extending along a direction of airflow;

arranging an air inlet at the body; wherein the air inlet is adapted to be in fluid communication with an interior of the inflatable chamber when the air inlet is arranged to be in open condition; and

providing an associating means at the body for associating the body with a subject.