BICYCLE HELMET WITH VENT
A bicycle helmet can include at least one ventilation opening and an exhaust port such that airflow enters the helmet through the ventilation opening and exits through the exhaust port, providing ventilation for a user. The orientation and location of the ventilation openings can reduce the aerodynamic drag of the helmet by delaying flow separation from the surface of the helmet and prevent airflow stagnation around the user's shoulders and neck.
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The present invention relates to protective helmets and bicycle helmets in particular.
DESCRIPTION OF THE RELATED ARTProtective helmets of many varieties exist to provide head protection for bicyclists. However, not only must a helmet provide adequate protection from serious head injury, preferably, the helmet is light weight, comfortable, and ventilated to help the rider stay cool.
SUMMARY OF THE INVENTIONOne aspect of at least one embodiment of the invention is the recognition that there exists a continuing need to develop protective bicycle helmets that increase rider ventilation without increasing the aerodynamic drag associated with conventional vent placements on bicycle helmets. In one embodiment, an aerodynamic bicycle helmet can include one or more ventilation openings or vents located on the sides of the helmet which act as an airflow control system to direct airflow into the interior of the helmet, providing ventilation for the rider. The airflow may then be exhausted from the helmet via an exhaust port located at the rear of the helmet.
Another aspect of at least one embodiment of the invention is the recognition that the ventilation openings may be oriented perpendicular to the local flow direction in order to minimize the flow disruption.
Yet another inventive aspect of at least one embodiment of the present invention is the recognition that the vents may have a small width and depth in comparison to their height perpendicular to the local flow direction in order to reduce aerodynamic drag associated with the vents.
Yet another inventive aspect of at least one embodiment of the present invention is the recognition that the airflow flowing into the helmet through the vents may exit the helmet through an exhaust port located in the wake region of the helmet.
In some embodiments, including the illustrated embodiment, a bicycle helmet is disclosed. The bicycle helmet desirably comprises a main unit having a cavity configured to receive a user's head, the main unit comprising a shell and a body, the main unit defining a front surface and a rear surface which have a parabolic profile when viewed from above when the user is in an aerodynamic position with the user's head lowered; a ventilation mechanism comprising at least one ventilation opening formed in a side surface of said main unit rear of a widest vertical cross section of the main unit, said ventilation opening having a height, a width, and a depth, and an exhaust port in a rear portion of the main unit wherein the height of the ventilation opening transverse to a local flow direction at said ventilation opening is the largest dimension of the ventilation opening; wherein said ventilation mechanism provides an airflow through said main unit due to airflow entering the main unit through the at least one ventilation opening and exiting the main unit through the exhaust port.
In other embodiments, including the illustrated embodiment, a bicycle helmet is disclosed. The bicycle helmet desirably comprises a body having a cavity configured to receive a user's head; a ventilation mechanism comprising at least one ventilation opening formed in a side surface of said main unit rear of the widest cross section of the main unit and an exhaust port formed substantially in a rear portion of the main unit, wherein said ventilation mechanism provides a flow of air through said main unit due to airflow entering the main unit through the at least one ventilation opening and exiting the main unit through the exhaust port.
In some embodiments, including the illustrated embodiment, a method for reducing aerodynamic drag while operating a bicycle is disclosed. The method is desirably achieved through providing an aerodynamic bicycle helmet comprising a body having a cavity configured to receive a user's head, a ventilation mechanism comprising at least one ventilation opening formed in a side surface of said helmet rear of the widest cross section of the main unit and an exhaust port formed in a rear portion of the main unit; placing said helmet on the user's head; orienting the user's head while operating a bicycle such that a local airflow direction at the ventilation opening is perpendicular to said opening; and allowing said airflow to enter the helmet through said ventilation opening and exit the helmet through said exhaust port.
These and other features, aspects, and advantages are described in greater detail below with reference to the drawings which are intended to illustrate, but not to limit, the present invention.
The following detailed description is directed to a specific embodiment of the invention. However, the invention may be embodied in a multitude of different ways as defined and covered by the claims.
Though many styles of bicycle helmets exist, the bicycle helmet of the present application will be discussed with reference to an aerodynamic bicycle helmet such as those used by competitive cyclists. It will be understood that features of the bicycle helmet discussed herein could be used for any helmet design in which low aerodynamic drag is desired and still obtain certain advantages.
To facilitate understanding of the invention, the illustrated embodiment is described in the context of an orientation system based on the orientation of the helmet 10 when worn by a user. As shown in
The front of the main unit 36 desirably has a parabolic shape in a horizontal plane as viewed from above or below, as seen in
As viewed from the front, as illustrated in
The body 30 of the helmet 10 is preferably constructed from an energy absorbing material, such as an expanded foam material, for example. However, other suitable materials may be used. The body 30 may be constructed from a variety of suitable manufacturing techniques that are known or apparent to one of skill in the art. The body 30 may be constructed of a single piece of material or may be constructed of multiple components. If the body 30 is constructed from multiple components, the components may be formed separately and then joined together or may be formed as individual layers of a unitary structure. For example, in one arrangement, multiple components may be joined together by an internal support structure or multiple materials may be molded in successive steps to form a unitary structure. Alternatively, the body 30 could comprise more than one piece secured to the shell 32 and not to one another.
The shell 32 preferably covers a portion of an outer surface of the body 30 and, desirably, provides protection to the body 30 in addition to providing aerodynamic benefits. In addition, the shell 32 may also provide an energy absorbing function. In the illustrated embodiment, the shell 32 covers a substantial portion of the outer surface of the body 30, including front, side, top and rear portions of the body 30. Preferably, the shell 32 is a relatively thin layer of a polycarbonate material. Desirably, an average thickness of the shell 32 is substantially less than an average thickness of the body 30. In one arrangement, the shell 32 may be injection molded onto a body 30 that has been formed in a previous process step. The inside surface of the shell 32 that covers the user's ears may be covered with a liner material such as IEPE; however, other materials may be used. The depth of the body DB is indicated on
Preferably, the helmet 10 also includes a retention assembly 80, which extends below a lower, rearward portion of the main unit 36, as shown in
The inventors recognized that the aerodynamic performance of a bicycle helmet can be affected by the surface roughness of the helmet, which is typically a result of conventional vent placement. In order to reduce the surface roughness factor which contributes to aerodynamic drag, the illustrated embodiment of the present invention desirably eliminates a vent or opening on the front surface 34 of the main unit 36. As shown in
As viewed from the top, shown in
The rear portion of the main unit 36 is also substantially parabolic as viewed from the front or the back but, in the illustrated embodiment shown in
The underside of the main unit 36 preferably defines an inner surface 38, as seen in
As discussed above,
The placement of the ventilation openings will affect the surface roughness of the helmet 10 which will in turn affect the aerodynamic drag, as discussed above. The placement of the ventilation opening 12 is an important issue when designing the bicycle helmet 10 for maximum drag reduction, as conventional vent placement can cause significant aerodynamic drag. In a preferred embodiment designed to minimize aerodynamic drag, such as that shown in
The geometry of the ventilation openings 12, including the cross sectional area, the ventilation opening 12 orientation, the height H of the ventilation opening 12, the width W of the ventilation opening 12, and the depth DR of the ventilation opening 12 influence the effectiveness of the ventilation mechanism and the aerodynamics of the helmet 10. Desirably, the depth DR is minimized in order to keep the frontal area of the main unit 36 as small as possible. Ventilation openings 12 on a main unit 36 are generally designed to promote the transfer of heat from the head of a user through forced convection. In the helmet 10 illustrated in
In some embodiments, including the illustrated embodiment, the ventilation openings 12 are preferably oriented such that the cross section of the openings 12 is perpendicular to a local flow direction 22 at the opening 12. The line 22, shown in
The ventilation openings 12 are used to manage the boundary layer by removing or diverting low energy boundary layer flow from the outside of the main unit 36 to the inside of the main unit 36 to allow the airflow to remain attached to the outside surface of the main unit 36 further down the main unit 36. The detachment of the boundary layer from the surface of the main unit 36 rearward of the plane 56 creates a high pressure zone or area of flow stagnation between the neck and shoulders of the user. This high pressure zone increases aerodynamic drag. The ventilation openings 12 are desirably placed such that the openings 12 are located in the region rear of the plane 56 indicating the widest point of the main unit 36 and in front of the plane 66 indicating the area of flow separation from the helmet, which may be located anywhere between halfway and two-thirds of the distance between the plane 56 and the rear of the main unit 36 as measured from the plane 56, as discussed above and shown in
Although this invention has been disclosed in the context of certain preferred embodiments and examples, it will be understood by those skilled in the art that the present invention extends beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the invention and obvious modifications and equivalents thereof. In addition, while a number of variations of the invention have been shown and described in detail, other modifications, which are within the scope of this invention, will be readily apparent to those of skill in the art based upon this disclosure. It is also contemplated that various combinations or sub-combinations of the specific features and aspects of the embodiments may be made and still fall within the scope of the invention. Accordingly, it should be understood that various features and aspects of the disclosed embodiments can be combined with or substituted for one another in order to form varying modes of the disclosed invention. Thus, it is intended that the scope of the present invention herein disclosed should not be limited by the particular disclosed embodiments described above, but should be determined only by a fair reading of the claims that follow.
Claims
1. A bicycle helmet comprising:
- a main unit having a cavity configured to receive a user's head, said main unit comprising a shell and a body, said main unit defining a front surface and a rear surface which have a parabolic profile when viewed from above when the user is in an aerodynamic position with the user's head lowered;
- a ventilation mechanism comprising at least one ventilation opening formed in a side surface of said main unit rearward of a widest vertical cross section of the main unit, said ventilation opening having a height, a width, and a depth, and an exhaust port in a rear portion of the main unit wherein the height of the ventilation opening transverse to a local flow direction at said ventilation opening is the largest dimension of the ventilation opening;
- wherein said ventilation mechanism provides an airflow through said main unit due to airflow entering the main unit through the at least one ventilation opening and exiting the main unit through the exhaust port.
2. The bicycle helmet of claim 1, wherein the local flow direction at the ventilation opening is perpendicular to the height of the ventilation opening.
3. The bicycle helmet of claim 1, wherein said exhaust port comprises at least one opening in the rear of the main unit.
4. The bicycle helmet of claim 1, where said exhaust port is located below a trailing top edge of the helmet.
5. The bicycle helmet of claim 1, wherein said exhaust port is located below a trailing bottom edge of the helmet.
6. The bicycle helmet of claim 1, wherein said ventilation opening is located forward of a plane defined by flow separation from the surface of the helmet.
7. The bicycle helmet of claim 1, wherein the height of said ventilation opening is substantially more than the width of said ventilation opening.
8. The bicycle helmet of claim 7, wherein the height of said ventilation opening is 6 times the width.
9. The bicycle helmet of claim 7, wherein the height of said ventilation opening is 8 times the width.
10. The bicycle helmet of claim 7, wherein the height of said ventilation opening is 6-8 times the width.
11. The bicycle helmet of claim 1, wherein a leading edge of said ventilation opening is formed in line with the side surface of the helmet.
12. The bicycle helmet of claim 1, wherein a leading edge of said ventilation opening is recessed inward from the side surface of the helmet.
13. The bicycle helmet of claim 1, wherein said rear surface tapers toward the rear of said body.
14. The bicycle helmet of claim 1, wherein said helmet has a substantially teardrop shape.
15. The bicycle helmet of claim 13, wherein said rear surface is bobbed to reduce the length of said body.
16. The bicycle helmet of claim 1 further comprising a top surface, wherein said top surface does not comprise any openings.
17. The bicycle helmet of claim 1 further comprising a front surface, wherein said front surface does not comprise any openings.
18. The bicycle helmet of claim 1 further comprising a substantially hollow rear portion of the helmet extending from the back of a user's head to the exhaust port, said rear portion formed such that a bottom surface of the rear portion is substantially flat and an upper surface of the rear portion is curved.
19. The bicycle helmet of claim 1, wherein said ventilation opening is located forward of a plane located half of the distance rearward from the widest cross section of the helmet to the rear of the helmet.
20. The bicycle helmet of claim 1, wherein said ventilation opening is located forward of a plane located two-thirds of the distance rearward from the widest cross section of the helmet to the rear of the helmet as measured from the widest cross section of the helmet.
21. A bicycle helmet comprising:
- a body having a cavity configured to receive a user's head;
- a ventilation mechanism comprising at least one ventilation opening formed in a side surface of said main unit rearward of the widest cross section of the main unit and an exhaust port formed substantially in a rear portion of the main unit;
- wherein said ventilation mechanism provides a flow of air through said main unit due to airflow entering the main unit through the at least one ventilation opening and exiting the main unit through the exhaust port.
22. A method for reducing aerodynamic drag while operating a bicycle, the method comprising:
- providing an aerodynamic bicycle helmet comprising a body having a cavity configured to receive a user's head, a ventilation mechanism comprising at least one ventilation opening formed in a side surface of said helmet rearward of the widest cross section of the main unit and an exhaust port formed in a rear portion of the main unit;
- placing said helmet on the user's head;
- orienting the user's head while operating a bicycle such that a local airflow direction at the ventilation opening is perpendicular to said opening; and
- allowing said airflow to enter the helmet through said ventilation opening and exit the helmet through said exhaust port.
Type: Application
Filed: Jun 22, 2012
Publication Date: Dec 26, 2013
Applicant: SPECIALIZED BICYCLE COMPONENTS, INC (Morgan Hill, CA)
Inventors: Duncan James Bradley (Cranleigh), Matthew John Williams (London)
Application Number: 13/531,273