Wind-stabilized baseball cap
A baseball cap including features for stabilizing the cap in a moving stream of air. The cap includes a modified bill having a downforce generator configured to create a relatively stagnate recirculation zone between the downforce generator and the head covering. This recirculation zone tends to negate the lifting effect found in prior art bills. The invention preferably also includes a vent through the bill. The vent is located behind the downforce generator, so as to connect the underside of the bill to the recirculation zone formed in the wake of the downforce generator. The vent is selectively closed by a flexible flap. The flap remains closed to prevent rain from passing through the vent. However, if pressure beneath the bill significantly exceeds pressure above the bill, the vent opens to equalize the pressure. This action prevents the creation of a net lifting force which might lift the cap off the wearer's head.
Not Applicable
BACKGROUND OF THE INVENTION1. Field of the Invention
This invention relates to the field of headwear. More specifically, the invention comprises a baseball cap having a modified bill configured to produce downforce when the cap is placed in a moving airstream.
2. Description of the Related Art
The “baseball cap” is one of the world's best known hats.
Those familiar with the art will know that such hats are made using a variety of technique. The example of
In this expression, v stands for the flow velocity at a given point, g stands for gravitational acceleration, h stands for the height above a reference plane, P stands for the pressure of the air at a given point, and ρ stands for the density of the air at a given point.
From this equation one may easily discern the fact that when a compressible fluid is flowing past an object at subsonic speeds, the faster the flow is in a particular region the lower the pressure will be in that region. When looking at
The flow passing under the bill, however, impacts the wearer's face 16. This produces a recirculation area denoted as stagnation region 20. The flow in this area is relatively slow. Thus, from Bernoulli's equation, one may accurately predict that the air pressure in the area beneath the bill will be greater than the air pressure in the area above the bill. The result is the creation of lift 24, which tends to lift the cap free of the wearer's head.
Prior hat designers have accounted for this phenomenon by angling the bill downward as shown. The downward angle has the effect of an airfoil having a negative angle of attack. The flow over the top therefore creates downforce 22. If the magnitude of downforce 22 exceeds that of lift 24, then the hat will stay on. Of course, the motion of the wearer's head alters the bill's angle of attack. If the user inclines her head slightly, downforce 22 will be greatly reduced. This will likely be the instant when the moving airstream lifts the cap free of the wearer's head and carries it away.
The loss of such a cap is a significant inconvenience. This is particularly true in a boating situation, where the hat is likely to blow overboard and be lost. Prior art designers have attempted to remedy this known problem in a variety of ways. For example, some caps have incorporated a bill having a hinged vent flap. The vent flap pivots upward if the pressure difference between the region beneath the bill and above the bill becomes large enough. Other designs have incorporated one or more fixed vents through the bill. Still other designs have incorporated a bill with a severe downward angle, so that the bill's angle of attack remains negative throughout the range of motion of the user's head.
While these prior art designs have in part remedied the problem, no prior art design has produced a good solution while still maintaining the conventional benefits of the traditional baseball cap. The present invention seeks to remedy these shortcomings.
BRIEF SUMMARY OF THE PRESENT INVENTIONThe present invention is a baseball cap including features for stabilizing the cap in a moving stream of air. The cap includes a modified bill having a downforce generator configured to create a relatively stagnate recirculation zone between the downforce generator and the head covering. This recirculation zone tends to negate the lifting effect found in prior art bills.
The invention preferably also includes a vent through the bill. The vent is located behind the downforce generator, so as to connect the underside of the bill to the recirculation zone formed in the wake of the downforce generator. The vent is selectively closed by a flexible flap. The flap remains closed to prevent rain from passing through the vent. However, if pressure beneath the bill significantly exceeds pressure above the bill, the vent opens to equalize the pressure. This action prevents the creation of a net lifting force which might lift the cap off the wearer's head.
The presence of gap 56 creates a recirculation zone behind the trailing edge of the downforce generator. The airstream impacting the upwardly inclined forward surface of the downforce generator creates downforce 22 (through stagnation pressure of the air impacting the device). Downforce 22 obviously tends to hold the hat down on the user's head. The creation of the recirculation zone in gap 56 tends to create relatively high pressure in this region, which places secondary downforce 48 on the upper surface of flap 36.
Flap 36 is made of a flexible material. It is attached to the bill by flap attachment 44 (which can be a sewn joint, an adhesive joint, etc.). The effect of this construction is that the leading edge of flap 36 remains in a fixed position with respect to the bill, but free end 46 can lift upward, thereby opening vent 34 and allowing flow to occur from below the bill to above the bill.
In the configuration shown in
In
The change in flow magnitude and direction shown in
Returning now to
Although the preceding description contains significant detail, it should not be construed as limiting the scope of the invention but rather as providing illustrations of the preferred embodiments of the invention. As an example, although the invention has been illustrated with a thin walled downforce generator, a solid or thick-walled design made of lightweight foam material could be substituted. Many other variations will be apparent to those skilled in the art. Thus, the scope of the invention should be fixed by the following claims rather than any specific examples provided.
Claims
1. A baseball cap, comprising:
- a. a head covering, including a forward region;
- b. a bill extending outward from said forward region of said head covering, said bill having a leading edge distal to said head covering and a trailing edge proximal to said head covering;
- c. a downforce generator, extending upward from said bill, wherein said downforce generator extends only part of the way from said leading edge of said bill to said forward region of said head covering, thereby creating a gap between said downforce generator and said forward region of said head covering; and
- d. a vent, extending through said bill into said gap.
2. A baseball cap as recited in claim 1, further comprising a flexible flap covering said vent.
3. A baseball cap as recited in claim 2, wherein:
- a. said flexible flap has a leading edge and a trailing edge;
- b. said leading edge of said flexible flap is secured to said bill; and
- c. said trailing edge of said flexible flap is free.
4. A baseball cap as recited in claim 1, wherein:
- a. said downforce generator has a middle portion, a first side extreme, and a second side extreme;
- b. said downforce generator has a splitter located in said middle portion, with said splitter being configured to divide said air flow into a first portion directed toward said first side extreme and a second portion directed toward said second side extreme.
5. A baseball cap as recited in claim 2, wherein:
- a. said downforce generator has a middle portion, a first side extreme, and a second side extreme; and
- b. said downforce generator has a splitter located in said middle portion, with said splitter being configured to divide said air flow into a first portion directed toward said first side extreme and a second portion directed toward said second side extreme.
6. A baseball cap as recited in claim 3, wherein:
- a. said downforce generator has a middle portion, a first side extreme, and a second side extreme;
- b. said downforce generator has a splitter located in said middle portion, with said splitter being configured to divide said air flow into a first portion directed toward said first side extreme and a second portion directed toward said second side extreme.
7. A baseball cap as recited in claim 1, wherein said downforce generator is a thin structure attached along said leading edge of said bill, thereby forming a cavity between said downforce generator and said bill.
8. A baseball cap as recited in claim 2, wherein said downforce generator is a thin structure attached along said leading edge of said bill, thereby forming a cavity between said downforce generator and said bill.
9. A baseball cap as recited in claim 3, wherein said downforce generator is a thin structure attached along said leading edge of said bill, thereby forming a cavity between said downforce generator and said bill.
10. A baseball cap as recited in claim 4, wherein said downforce generator is a thin structure attached along said leading edge of said bill, thereby forming a cavity between said downforce generator and said bill.
11. A baseball cap as recited in claim 7, further comprising a drain passing through said downforce generator, thereby draining said cavity.
12. A baseball cap as recited in claim 7, further comprising a drain passing through said bill, thereby draining said cavity.
13. A baseball cap, comprising:
- a. a head covering, including a forward region;
- b. a bill extending outward from said forward region of said head covering, said bill having a leading edge distal to said head covering and a trailing edge proximal to said head covering;
- c. a downforce generator, assuming the form of an inclined wall sloping upward and rearward from said leading edge of said bill and being attached thereto;
- d. wherein said inclined wall extends only part of the way from said leading edge of said bill to said forward region of said head covering, thereby creating a gap between said downforce generator and said forward region of said head covering; and
- e. a vent, extending through said bill into said gap.
14. A baseball cap as recited in claim 13, further comprising a flexible flap covering said vent.
15. A baseball cap as recited in claim 14, wherein:
- a. said flexible flap has a leading edge and a trailing edge;
- b. said leading edge of said flexible flap is secured to said bill; and
- c. said trailing edge of said flexible flap is free.
16. A baseball cap as recited in claim 13, wherein:
- a. said downforce generator has a middle portion, a first side extreme, and a second side extreme; and
- b. said downforce generator has a splitter located in said middle portion, with said splitter being configured to divide said air flow into a first portion directed toward said first side extreme and a second portion directed toward said second side extreme.
17. A baseball cap as recited in claim 13, wherein said downforce generator is a thin structure attached along said leading edge of said bill, thereby forming a cavity between said downforce generator and said bill.
18. A baseball cap as recited in claim 14, wherein said downforce generator is a thin structure attached along said leading edge of said bill, thereby forming a cavity between said downforce generator and said bill.
19. A baseball cap as recited in claim 13, further comprising a drain passing through said downforce generator, thereby draining said cavity.
20. A baseball cap as recited in claim 13, further comprising a drain passing through said bill, thereby draining said cavity.
Type: Application
Filed: May 23, 2008
Publication Date: Nov 26, 2009
Inventor: Thomas H. Greene, JR. (Madison County, FL)
Application Number: 12/154,562
International Classification: A42C 5/04 (20060101); A42B 1/00 (20060101); A42B 1/02 (20060101);