Patent Application
20140190097
The present invention relates to overhead roll-up doors, and more specifically to door assembly, wind lock, and side column configurations for an overhead roll-up door.
In some environments, overhead roll-up door assemblies, and in particular the door panels in the assemblies, are required to withstand great amounts of force and pressure resulting from environmental causes. For example, large differences or variations in air pressure on opposing sides of overhead roll-up door panels, or high winds directed at one side of a door panel, may cause a significant force to be imparted on one side of the door panel. In door assemblies which have large door panels, thousands of pounds of force due to wind and/or air pressure may be imparted on the door. These large forces may cause the door panel to unwantedly disengage from the door assembly and any side columns or guide tracks in which a portion of the door is positioned for travel, through the gap or opening which allows for the side columns to engage the door panel. Disengagement of the door panel may cause damage to the door and surrounding structures, may cause injuries to individuals proximate the door panel, and may prevent the door from properly operating and/or properly opening and blocking or closing the opening proximate the door.
Wind locks are an effective technique for keeping a flexible overhead roll-up door panel engaged within vertical side columns and guide tracks in high speed overhead roll-up door assemblies. There are different types of “wind locks” known within the industry, like, for example, rollers, buttons, and knobs. However, buttons and knobs, for example, fail to hold up to very large wind loads when used with large doors, or in the face of high winds or air pressure differentials as they tend to break off the door panel. Therefore, under these conditions, it is common to use a thick strip of rubber along the continuous vertical edges of the door panel to hold it within the side columns and guide tracks and prevent the door panel from “blowing out” while under a wind load.
Because the door panel and wind locks move vertically within and may engage the side columns as the door is opening and closing, it is desirable to move the door panel while generating as little friction as possible. Low friction between the wind locks and side columns permits a lower-powered HP motor to lift the door panel, and also allows the door panel to close completely (the door typically closes under its own weight) without stalling or binding up as the door panel is lowered in higher wind loads or greater air pressure differentials. Therefore, it is also common for the industry to overlap a thick rubber or similar wind lock with a low-friction fabric polyethylene terephthalate (PET) material, or the like.
In addition to combating wind loads, flexible overhead roll-up door panels must also be able to disengage when impacted with a transverse force by an object or vehicle passing proximate or through the door. Ideally, the door panels are capable of disengaging after impact without damaging the door assembly (panel, wind locks, side columns, motor) or any surrounding structures. In order to avoid such damage, it is common in the industry to use a 45 degree (or similarly angled) beveled inner surface on the wind lock and a mating 45 degree angled (or similarly complementary angled) engagement surface on the side column where the wind lock may engage or contact the side column with the door panel extending through a gap in the side column proximate the angled, mating surface. Utilizing a gap and mating angles may create a “wedge” effect as a portion or more the wind lock is pulled into and potentially through the gap in the side column. The wedge effect may allow the wind lock to compress and more easily slide or fit through a gap in the side column and “open” or expand the gap in the side column to allow the door panel to escape, instead of simply being pulled against the side column resulting in either the wind lock being ripped off, the panel being torn, or the side columns being bent or damaged during impact. The combination of the complementary angled faces on the wind lock and side column may also act to move or flex or rotate a portion of the side column to expand the gap in the side column to more easily allow the wind lock and door panel to escape. While this effect is desirable if the door panel is impacted or hit by an object, it is undesirable in response to a wind load being applied to the door panel.
Using continuous mating angles along the entirety of the door panel has a disadvantage—it may increase the friction between the wind lock and side column when the door is opening or closing. Under wind loads or when an air pressure differential exists, the door panel may “bow out.” The bowing of the door panel may pull the wind locks inward, towards the center of the opening or door panel, causing the wind locks to engage the side columns, or more problematically become wedged in the side column gaps, as the door panel is opening or closing. For example, the mating angled surfaces of the wind locks and side columns can result in the overall increase in friction. This may create wear on the wind locks, door panel, and side columns, and puts unwanted stress on the motor controlling the operation of the door panel. When under a high wind load, these wind locks may also become stuck in the gap and side column, causing the door panel to stick, potentially damaging the door panel, the wind locks, and the motor.
Therefore, it would be advantageous to design a wind lock, door panel, side column and overall door assembly which eliminates the use of continuous mating 45 degree or similarly complementary angles in the wind lock and side column to substantially lower friction and enhance satisfactory wind load response, while at the same time maintaining or enhancing a satisfactory wind load response and the disengageability of the door panel if the door panel is impacted with a transverse force.
The present invention is provided to solve these and other problems.
The present invention is directed to providing an overhead roll-up door having a better wind lock which provides proper support in the face of wind loads while substantially reducing friction in known door assemblies. The wind lock of the present invention will still allow an associated door panel to disengage from the assembly if impacted by a transverse force from an object or vehicle traveling proximate the door panel. In order to accomplish this goal, the door assembly, door panel, and wind lock in the present disclosure eliminates the traditional continuous 45 degree bevel and mating side column angle proximate a side column gap with a wind lock and side column having mating 90 degree faces or edges. It has been found by the inventors of this application that this configuration maintains a satisfactory wind load response while substantially reducing, if not eliminating, a multiplication factor for overall friction of the 45 degree bevel and mating side column configuration known in the prior art.
The disclosure herein provides a door assembly and wind lock having the low-friction benefits of the 90 degree surfaces, but also which may be “broken away” without damaging the door panel, wind lock, side columns, or any surrounding structures if the door panel is impacted. In order to insure that the door panel and wind lock can escape the side column when the door panel is impacted by a transverse force, the wind lock may include a compound or angled beveled edge at the lower end or towards the bottom of the door panel. The compound beveled wind lock may be, for example, a 60 degree angle from the bottom of the door panel with about a 30 degree bevel.
According to one aspect of the invention, a wind lock for an overhead roll-up door is provided. The wind lock includes a first edge, the first edge being substantially straight and being capable of extending substantially perpendicular vertically from a face of a door panel to which the wind lock may attach to. The wind lock includes a second edge which has an angled face which is beveled with, or extends at an angle vertically from, the face of the door panel. The second edge may extend at an angle from the first edge.
The wind lock may be made of rubber and may also include an outer edge, the outer edge being spaced apart from and located opposite the first edge. The second edge may extend horizontally at an angle to the first edge, extending between the first edge and the outer edge of the wind lock.
According to one aspect of the intention, a door panel for an overhead roll-up door assembly is provided. The door panel includes a top edge, a bottom edge, opposing vertical side edges, a first face, a second face, and at least one wind lock. The at least one wind lock may be attached to the door panel proximate one of the opposing vertical edges. The at least one wind lock may have a first portion having a first edge and a second portion having a second edge, wherein the first edge extends vertically, substantially perpendicular from the first or second face of the door panel, and is located a first distance from the opposing vertical edge proximate the at least one wind lock. The second edge may be beveled such that it extends vertically from the first or second face of the door panel at an angle to the door panel.
The second portion and the second edge may extend laterally across the first or second face of the door panel at an angle to the first edge. For example, the second edge may begin proximate the first edge of the wind lock and be angled outward, towards the opposing vertical edge proximate the at least one wind lock. In this configuration the second portion may begin proximate the first edge and terminate close to the opposing vertical edge of the door panel proximate the wind lock.
The at least one wind lock may also include an exterior edge opposite the first edge. The exterior edge may be positioned closer to, and in some cases may substantially align with, the opposing vertical edge proximate the at least one wind lock. The exterior edge may extend vertically from the first or second face of the door panel. The second edge of the wind lock may then extend laterally across the first or second face of the door panel from the first edge to the exterior edge at an angle to the bottom edge of the door panel. The angle may be 60 degrees or the like.
The at least one wind lock may also include a top face extending substantially parallel to the door panel between a top edge or portion of the first edge and a top edge or portion of the exterior edge. At least a portion of the door panel located proximate the first edge, the first edge, and the top face of the wind lock may be covered in a friction reducing material like, for example, PET.
Regardless of the configuration, the second edge may be beveled so as to extend vertically from the first or second face of the door panel at an angle of 30 degrees to the first or second face of the door panel.
The door panel may further include at least a second wind lock, the second wind lock being attached proximate the opposing vertical edge opposite that to which the at least one or first wind lock is attached. The second wind lock may be constructed and positioned substantially similar to the first or at least one wind lock with a first portion having a first edge and a second portion having a second edge. The first edge of the second wind lock may extend vertically, substantially perpendicular from the first or second face of the door panel and be located a distance from the opposing vertical edge proximate the second wind lock. The second wind lock may also include a second edge which is beveled such that it extends vertically from the first or second face of the door panel at an angle to the door panel.
According to one aspect of the invention, a side column for an overhead roll-up door is provided. The side column includes a base portion and an outer cover portion. The outer cover portion may have a parallel portion and a perpendicular portion. The parallel portion may be substantially parallel to, and spaced apart from, the base portion a first distance so that the parallel portion and base portion at least partially define an area. The area between the parallel portion and the base portion at least partially defines a vertical channel for receiving and engaging a portion of, and guiding, a door panel and any attached wind locks used in conjunction with the side column. The perpendicular portion may extend substantially perpendicular from the parallel portion in a direction towards the base portion. The perpendicular portion may terminate before extending to the base portion so that a gap extending a second distance, between an end of the perpendicular portion and the base portion exists. This gap may be less than the first distance between the parallel portion and the base portion.
The side column may include a guard piece operably attached to the perpendicular portion proximate the gap between the perpendicular portion and the base portion.
In order to attach the outer cover portion to the remainder of the side column, it is contemplated that the side column may include an attachment element, like for example a mounting bolt, which operably attaches the parallel portion to the side column. A resilient member may be operably connected to the side column by the attachment member. The outer cover portion may be able to compress the resilient member to pivot or rotate the outer cover portion outwards to expand the gap. The resiliency of the resilient member will force the outer cover portion to return to a closed position, re-establishing the gap at the second distance, once any need for an increased or expanded gap is removed.
According to one aspect of the invention, an overhead roll-up door assembly for selectively opening and closing an opening bounded by a top, a bottom, and opposing sides is provided. The overhead roll-up door assembly includes a door panel having a top edge, a bottom edge, a first face, a second face, and opposing vertical edges. At least two wind locks are attached to the door panel, each wind lock having a thickness and being attached proximate one of the opposing vertical edges. Each wind lock further includes a first portion having a first edge and a second portion having a second edge. The first edge extends substantially perpendicular vertically from the first or second face of the door panel when the wind lock is attached thereto and is located a distance from the opposing vertical edge proximate each respective wind lock. The second edge is beveled such that it extends vertically from the first or second face of the door panel at an angle to the door panel. The door assembly also includes at least two side columns positioned on opposite sides of the opening such that one side column is proximate each opposing side of the opening. Each side column has a base portion and an outer cover portion, with each outer cover portion having a parallel portion and a perpendicular portion. Each parallel portion is substantially parallel to, and spaced apart from, its respective base portion a first distance, defining an area between there between. The area defined between the parallel portion and the base portion at least partially defines a vertical channel in each side column for engaging and guiding the door panel and the attached wind locks as the door panel is opened and closed. Each perpendicular portion extends substantially perpendicular from the respective parallel portion in a direction towards the respective base portion. Each perpendicular portion terminates before extending to the respective base portion so a gap extending a second distance between an end of each perpendicular portion and the respective base portion is formed. The second distance or gap is less than the first distance between the respective parallel portion and the respective base portion. The combined thickness of each wind lock and the door panel is also greater than the second distance or gap in each side column. The perpendicular portion of each of the respective side columns may engage one of the at least two wind locks when a wind load is applied to the door panel to prevent the door panel from escaping the vertical channel in each side column.
The second edge of each wind lock may extend laterally across the first or second face of the door panel at an angle to each respective first edge. For example, each second edge may extend laterally outward across the first or second face of the door panel at an angle to each respective first edge, beginning proximate each respective first edge and terminating closer to each respective opposing vertical edge proximate each wind lock than the respective first edge.
Each wind lock may include an exterior edge opposite each respective first edge. Each exterior edge may be positioned closer than each respective first edge to, or even substantially aligned with, the opposing vertical edge proximate each respective wind lock. The exterior edge may extend vertically from the first or second face of the door panel. Each second edge may then extend laterally across the first or second face of the door panel from the respective first edge to the respective exterior edge at an angle of 60 degrees to the bottom edge of the door panel.
Each wind lock may also include a top face which extends substantially parallel to the first or second face of the door panel between a top edge or portion of the first edge and a top edge or portion of the exterior edge. At least a portion of the door panel located proximate the first edge, the first edge, and the top face may be covered in friction reducing material such as PET fabric.
In the overhead roll-up door assembly, each side column may also have a guard piece operably attached to the perpendicular portion proximate the gap between the perpendicular portion and the base portion. The guard piece may be configured to engage each respective wind lock when a wind load is applied to the door panel.
Each side column may include an attachment member, like for example a mounting bolt, for operably attaching the respective outer cover portion to each respective side column. Each side column may further include a resilient member, like for example a metal or rubber washer, operably connected to each side column by the respective mounting bolt. Each resilient member may allow the outer cover portion of each side column to rotate and expand the gap in response to a large force being applied to the outer cover portion resulting from the door panel being impacted by an object or vehicle. The resilient member held against the outer cover portion of each side column will allow an engaged wind lock and vertical edge to pivot or rotate the outer cover portion of the side column so that the engaged wind lock and vertical edge may escape the side column when a transverse force impacts the door panel. The second edge of each wind lock will be configured to engage the side column in a manner which allows it to pass through and expand the gap in each respective side column by rotating the cover portion of the respective side column. The resilient member may compress and deform, allowing the cover portion to further rotate and allow the first portion and first edge to escape the side column as well. Once the door panel and wind lock have passed completely through the gap and out of the side column, the resilient member may then cause the outer cover portion to rotate back into position, re-establishing the gap at the second distance.
Additional features, advantages, and embodiments of the invention may be set forth or apparent from consideration of the detailed description and drawings. Moreover, it is to be understood that the foregoing summary of the invention and the following detailed description, drawings and attachment are exemplary and intended to provide further explanation without limiting the scope of the invention as claimed.
The accompanying drawings, which are included to provide a further understanding of the disclosure, are incorporated in and constitute a part of this specification, illustrate embodiments of the disclosure and together with the detailed description serve to explain the principles of the disclosure. No attempt is made to show structural details of the disclosure in more detail than may be necessary for a fundamental understanding of the disclosure and the various ways in which it may be practiced. In the drawings:
The present disclosure is further described in the detailed description that follows.
The disclosure and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments and examples that are described and/or illustrated in the accompanying drawings and detailed in the following description. It should be noted that the features illustrated in the drawings are not drawn to scale, and features of one embodiment may be employed with other embodiments as the skilled artisan would recognize, even if not explicitly stated herein. Descriptions of well-known components and processing techniques may be omitted so as to not unnecessarily obscure the embodiments of the disclosure. The examples used herein are intended merely to facilitate an understanding of ways in which the invention may be practiced and to further enable those of skill in the art to practice the examples of the disclosure. Accordingly, the examples and embodiments herein should not be construed as limiting the scope of the invention.
As seen in
While the angled inner face and cooperatively angled side column may be effective in maintaining alignment of the door panel while also allowing for it to disengage if the door panel is impacted, the angled portion has multiple disadvantages. As the panel “bows out” due to the catenary effect when a wind load is applied to the door panel, see for e.g.
The present invention is aimed to provide an improved wind lock system by eliminating the traditional 45 degree bevel along the entire length of the wind lock, and utilizes low-friction I high-wind load aspects of a 90 degree or perpendicular face along a substantial portion of the length of the wind lock (and along the outer vertical edges of the panel). This configuration at least substantially eliminates the 2.41 multiplication factor mentioned above. Moreover, a compound bevel angle may be provided at the lower end of the wind lock to allow for the wind lock and associated door panel to break-away should it be impacted. By beveling the bottom of the wind lock and utilizing a flexible side column cover, the door panel may break-away without having to re-attach or replace components, and eliminate any possible wedge effect resulting from a completely beveled wind lock becoming locked or wedged in the side column during vertical movement.
First edge 214 extends substantially perpendicular from one face (shown as 200a) of the door panel 200. Top face 216 is covered by wear and friction reducing strip of fabric 212a, while door panel 200, proximate wind lock 204, may be covered in a strip of wear or friction reducing fabric 212b. First edge 214 may also be covered in a strip of wear reducing fabric 212c. As seen in
In order to better see the construction of the side columns and how the door panel and wind lock engages and travels and rests within the side column under normal conditions,
As seen in
As seen in
Perpendicular portion 314 of outer cover portion 310 extends substantially perpendicular from parallel portion 312, in a direction towards base portion 308. The perpendicular portion terminates prior to reaching the base portion so that gap 306 is formed between the perpendicular portion and the base portion. Gap 306 should extend a second distance H, which is less than both distance G, and the thickness T of the body of the door panel and wind lock 204. Gap 306 should, however, be greater than the thickness U of the body of the door panel 200. Configuring gap 306 in this manner allows for door panel 200 to extend through the gap, and easily travel and be guided up and down as the door is opened and closed without engaging the side column, while also preventing wind lock 204 from escaping side column 304 under normal or wind load conditions.
When a wind load is applied to door panel 200, first portion 204a of wind lock 204 engages side column 304 and perpendicular portion 314. Since a wind load or pressure differential is typically uniformly applied to the door panel, second portion 204b of the wind lock will not engage the side column perpendicular portion as it is angled away from the edge of first portion 204a in a manner which prevents engagement, which substantially prevents second portion 204b and second edge 226 from contacting side column 304 and wedging in gap 306 as the door panel opens and closes. This allows the door panel to open and close with significantly reduced friction from prior art door panels and wind locks as the wedge effect is substantially limited because of the outward angling of the second portion 204b.
However, having an angled-beveled or second portion will provide the door panel with the ability to disengage if the door is impacted by a vehicle or other object attempting to travel through or proximate opening 308, particularly if the portion of the door panel proximate the angled beveled portion is impacted. An impact force, unlike a wind load or air pressure differential, is generally concentrated at a particular place on the door panel. At that location, the door panel will receive a significant force, causing significant bowing at that location, causing the portion of the wind lock at that location to be pulled into engagement with the side column. Placing the second or beveled portion of the wind lock proximate the bottom of the door panel, rather than in the middle or at the top better increases the disengage-ability of the door panel and wind lock, as most impacts occur proximate the bottom of the door panel as a vehicle or the like tries to sneak under a closing door or approaches an opening door too fast. Placing the second or beveled portion proximate the bottom of the door panel allows for the beveled portion to engage the side column when the door panel is impacted, allowing the beveled portion to push through and open the gap in the side column so that the entire wind lock and door panel can more easily escape the side column.
In order to allow for the gap to expand and side column 304 to be opened, the side column may include mounting bolt 320, resilient member 322, and pivot point 324, all of which act to connect and hold outer cover portion 310 in place, while also allowing it to open and pivot and move when necessary.
As seen in
Resilient member 322 may be a compression or washer spring which is compressible and has a resiliency which allows the washer, and in turn outer cover portion 310, to remain in place until an impact force great enough to compress the washer is impacted on the door panel. The resiliency will also allow the cover to return to the normal, resting, unengaged position once the wind lock has passed there through. In order to provide more or less resiliency, washer 322 may be replaced with a thicker or thinner, or more or less resilient, washer. Increasing or decreasing the resiliency will allow outer cover portion 310 to pivot open under higher or lower forces respectively, which will allow door panel 200 to escape less or more easily. For example, in environments where wind load is generally minimal but traffic proximate the door panel is very high, rubber washers of varying thicknesses may be utilized. Rubber washers tend to have substantial amounts of give which allow for the side column to deform or open more easily when force is applied from the door panel and wind lock resulting from an impact on the door panel. However, in environments which have high wind loads, the use of a rubber washer may not be ideal as a rubber washer may have too much give and may allow a door panel to escape as a result of the force imparted on the side column by the door panel and wind lock because of a wind load. In these environments, a steel washer or the like may be beneficial as it provides more rigidity to prevent the side column from deforming from resulting forces. While a steel washer may provide more rigidity in the face of wind loads, a steel washer will still allow the side column to deform and the outer cover portion of the side column to rotate as a result of forces occurring because of an impact on the door panel. Alternatively, rather than adjust the washer size or resiliency, the resiliency of the washer may be adjusted by loosening or tightening bolt 320.
Pivot point 324 may be a simple hinge, a ball/joint or similar pivoting element, or may alternatively be a spring hinge or the like to provide additional support or resiliency to outer cover portion 310. So long as outer cover portion 310 may open and close at pivot point 324, any combination or element known in the art may be used.
The cantenary angle THETA in
THETA=ASIN(C/2R)
C=S−2G
S=total panel width
G=gap between the windlock and side column before engagement
R=(C2/4+H2)/2H
H˜( 3/16*(S2−C2)0.5
The tension T in the door panel due to the cantenary effect can be found by determining the forces applied on the panel in both the x- and y-directions as shown in
2Ty=Fw=Wind Load
Ty=Fw/2
where Ty is the tension in the y-direction on the door panel and Fw is the force of the wind on the door panel. In order to determine the tension T in the door panel as shown, the Ty may be used:
T=Ty/sin(THETA)
Substituting the value of Ty into the equation provides:
T=Fw/2 sin(THETA)
The tension in the x-direction (the value of Tx) as shown can likewise be found using the value of Ty:
Tx=Ty/tan(THETA)
Tx=FW/2 tan(THETA)
In prior art side columns—like that seen in
Fax=Tx
Tx=Fw/2 tan(THETA)
Fax=Fw/2 tan(THETA)
Using the forces in the x-direction, the perpendicular force (Fa) on the side column and the force in the y-direction (Fy) can be calculated as follows:
Fa=Fax/sin(THETA SC)
Fay=Fax/tan(THETA SC)
Where THETA SC is the angle of the side column as shown, for example, in
Fby=Fay+Ty
Ty=Fw/2
Fby=Fax/tan(THETA SC)+Fw/2
Using the forces on both the door panel and side column, the frictional forces on each side column and the door panel can be found. Each contact point between the side column and the door panel (and any wind locks) will have a coefficient of friction. At point A in
Ff=Fa*COFa+Fby*COFb
If COF=COFa=COFb, assuming the same materials are used for each part of the side column, then the force of friction on each side column becomes:
Ff=COF*(Fa+Fby)
Inasmuch as both side columns engage the door panel, the total friction on the door panel (Ft) will equal 2×Ff.
The following calculations demonstrate the wedge effect of the 45 degree prior art wind lock without taking into account any wind load. Without a wind load, Ty=0. The comparison between a prior art side column utilizing angled side columns and wind locks and the side columns and wind locks of the present invention shows a significant reduction in the force of friction when the side columns and wind locks of the present invention are used.
Using a standard angle of 45 degrees for THETA SC in a prior art side column like that shown in
Ff=COF(Fa+Fby)
Fa=Fax/sin(45)=1.414Fax
Fby=Fay+Ty
Fay=Fax/tan(45)=Fax
Ty=0
Ff=2.414*COF*Fax
This shows that, before taking into effect wind load, the frictional force for each prior art side column having a 45 degree angle will be equal to approximately 2.414 multiplied by the coefficient of friction at points A and B multiplied by the force of friction in the x-direction at the side column.
For the present invention, the angle THETA SC will be 90 degrees. Using the equations established above, the following frictional forces for each side column, before taking into account any wind load, can be calculated:
Ff=COF(Fa+Fby)
Fa=Fax/sin(90)=Fax
Fby=Fay+Ty
Fay=0(only an x-directional component)
Ty=0
Ff=COF*Fax
As seen from the resulting calculations, the force of friction on each side column in the present invention is 2.414 times less than a standard 45 degree angled side column in the prior art. This reduction in friction results in less wear on both the door panel and the side column and helps preserve the motor used to open and close the door panel.
When factoring in a wind load, the frictional force on a 45 degree angled wind lock will vary slightly. For a side column and door assembly for the present invention, the force of friction under a wind load becomes:
Ff(90)=COF(Fa+Fby)
Fa=Fax
Fay=0(only an x-directional component)
Fby=Ty=Fw/2
Ff(90)=COF(Fax+Fw/2)
Fax=[Ff(90)−(Fw/2)]/COF
Ff(45)=2.414*COF*Fax
From above,Ff(45)=2.414*COF*[Ff(90)−(Fw/2)]/COF
Ff(45)=2.414[Ff(90)−(Fw/2)]
As seen from this calculation, the factor by which the frictional force is decreased in a door assembly utilizing the present invention will be reduced, however the amount of reduction in friction will vary dependent on the wind load on the door panel.
While the disclosure has been described in terms of exemplary embodiments, those skilled in the art will recognize that the disclosure can be practiced with modifications in the spirit and scope of the appended claims. These examples are merely illustrative and are not meant to be an exhaustive list of all possible designs, embodiments, applications or modifications of the disclosure.
This application claims priority to U.S. Provisional Application Ser. No. 61/750,202 filed Jan. 8, 2013, the contents of which are fully incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61750202 | Jan 2013 | US |
