Abstract:
Apparatus and methodology for discharging static electricity from a vehicle which uses a discharge mechanism that does not contact the roadway (Earth) when the vehicle is in forward motion to reduce, or completely avoid, frictional wear on the discharge mechanism. In one embodiment, the displacement between the discharge mechanism and the roadway is obtained by way of wind force generated by the motion of the vehicle itself. A properly oriented and hinged windscreen attached to the conductive path discharge mechanism can be used for this purpose. Other embodiments including magnetically controlled lifting and holding devices can be used.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention: 
         [0002]    The present invention relates generally to apparatus and methodology for discharging static electricity from a vehicle and, more particularly, to avoiding wear and tear on the electrical conductor which discharges the static electricity to ground. 
         [0003]    2. Description of Prior Art: 
         [0004]    Static electricity buildup is a fundamental phenomenon of nature, and we all have experienced it in one form or another. Static electricity varies widely in energy level, from a miniscule level where one barely notices an annoying spark at the end of one&#39;s finger as one touches a metal object in a dry environment after walking across a carpet, all the way up to the highly dramatic and dangerous lightning flashes during a summer thunderstorm. Both are examples of static electricity discharge. 
         [0005]    Static electricity is a bigger problem in dry climates such as the southwest U.S. than in humid climates such as the northeast U.S., because water vapor in places of high humidity forms a natural leakage path for the static electricity. All motor vehicles, trucks, cars, buses etc., can build up static electricity charge relative to ground because their rubber tires can act as insulators between the body of the vehicle and Earth. 
         [0006]    Under the wrong conditions, motor vehicle static electricity discharge can be a hazardous event. For example, if a gasoline tanker truck builds up static charge and somehow discharges that static electricity in the presence of fumes from the gasoline in the truck, then an enormous explosion may occur. It is, therefore, important to safely discharge static electricity from vehicles. 
         [0007]    Most of us are familiar with the image of a gasoline tanker truck driving down the highway while dragging a steel chain behind, along the roadway. This is a prior art approach which discharges the static electricity while the truck is in motion because of the scraping of the electrically-conductive metal chain against the roadway. Referring to  FIG. 1  (Prior Art) truck  100  is shown with truck body  101 , front wheels  102  and rear wheels  103  supported by roadway  104 . Truck body  101  has a metal chain  105  mounted from a conductive contact such as an axel located underneath the truck. The chain is shown to be in substantial contact with roadway  104 . This contact is maintained regardless of whether the truck is in forward motion, is stopped, or is in reverse motion. This may be an effective way to reduce static electricity buildup, but it is only good if the chain is in contact with the roadway. At some point, after a long haul across the country, or after other excessive usage, road friction eventually causes the chain to wear out, and the effective discharge path to ground through the chain becomes intermittent or non-existent. When the truck driver exits the truck through door  106  there could be a static electricity discharge through that individual to ground, if the chain had worn away during transit, and if the driver touches the truck and ground at the same time which is very likely. 
         [0008]    Also, there are other kinds of vehicles which can benefit from a safe static discharge path. The assignee of the present invention is a telecommunications company presently involved in installing a fiber to the premises (FTTP) infrastructure. The trucks used by the assignee&#39;s installers for this purpose contain a substantial amount of sensitive fiber splicing equipment and other sensitive equipment such as, e.g., line card installation equipment. All of this equipment can be very susceptible to, and negatively affected by, static electricity buildup. Thus, in addition to being a hazard to the technician installer who is driving the truck and who can, unknowingly, form a discharge path through his/her body from the truck to ground upon opening door  106  and setting foot on the ground while touching the truck, static electricity buildup can also wreak havoc with this sensitive equipment inside the truck. 
         [0009]    Therefore, there is a need to always have a safe discharge path for static electricity in place from the truck to ground prior to any occupants in that truck opening the door to egress. This requires a technique for avoiding wear-out of the discharge path from road friction. Applicant provides such a technique with the present invention which addresses the problems noted in the prior art. 
       SUMMARY OF THE INVENTION 
       [0010]    Embodiments of the present invention include apparatus and methodology for discharging static electricity from a vehicle on a roadway. Flexible and electrically-conductive material is suspended from beneath the vehicle. The material is sufficiently long to normally be in contact with the roadway when the vehicle is stopped. The material is oriented in a direction relative to the direction of forward motion of the vehicle, and is sufficiently lightweighted, to enable a wind that is created by the forward motion to automatically lift the material from the roadway and break the contact during occurrence of the forward motion. Thereby, the static electricity is discharged from the vehicle through the material to the roadway when the vehicle is stopped, and the material does not experience frictional force from the roadway when the vehicle is moving in a forward direction. In a particular embodiment, the material can be a 6-12 inch wide (approximate) strip of flexible, non-corrosive, electrically-conductive mesh or ribbon fabricated from a suitable alloy such as, for example, stainless steel alloy, brass alloy, etc. 
         [0011]    In another embodiment of the present invention, a wind-engagement mechanism is suspended from the vehicle and supports the material. The mechanism is oriented in a direction to encounter wind resistance when the vehicle is moving forward. This causes the mechanism to raise the material from the roadway and break the contact. 
         [0012]    In yet another embodiment, the electrically-conductive material can be fabricated from a flexible metal rod or spring. If the material encounters debris and/or holes in the roadway when the vehicle is moving in the reverse direction, damage to the wind-engagement mechanism is avoided by the conductive material being formed from the flexible metal rod or spring, because the end of the rod or spring which makes contact with the roadway is curved upward to permit it to ride over the debris and slide over the holes. Alternatively, the end of the rod can be affixed to a rotatable and electrically conductive metal wheel which makes contact with the roadway and can roll over the debris and the holes. The rod or spring can, likewise, be made from stainless steel or brass or other suitable non-corrosive and electrically-conductive metal. 
         [0013]    It is thus a general object of the present invention to provide an improved technique for discharging static electricity from a vehicle. 
         [0014]    It is another general object of the present invention to provide an improved technique for discharging static electricity from a vehicle without allowing vehicle motion to wear-out the electrically conductive discharge path between the vehicle and ground. 
         [0015]    Other objects and advantages shall become apparent after reviewing the detailed description of the preferred embodiments in conjunction with the drawings in which: 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  shows a prior art technique for static electricity discharge from a vehicle; 
           [0017]      FIG. 2  is an exemplary diagram of an embodiment of the present invention when viewing it from the rear of a stationary vehicle from which it is mounted; 
           [0018]      FIG. 3  is an exemplary diagram of the embodiment of  FIG. 2  when viewing it from the rear of a forward-moving vehicle from which it is mounted. 
           [0019]      FIG. 4  is another view of the embodiment of  FIG. 3  showing directions of vehicle motion and wind force; and 
           [0020]      FIG. 5  depicts another embodiment of the present invention which avoids malfunction during vehicle back-up due to debris and/or holes in the roadway. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0021]      FIG. 2  is an exemplary diagram of an embodiment  200  of the present invention when viewing it from the rear of a stationary vehicle from which it is mounted. Axel or truck chassis  201  is located underneath the truck body (not shown in this Fig.). Connected to axel  201  is flexible, electrically conductive material strip  205  having a width of several inches and a length sufficient to touch roadway  104  when the truck is not moving, as shown. Material  205  is lightweight and can be lifted or lofted into the air by a breeze or wind created by forward movement, thereby avoiding frictional forces while the truck is moving forward. Wind-engagement screen (or sail or wing)  204  is suspended from axel  201  by flexible supports  202  and  203 . Material  205  is connected to, and supported by, wind screen  204  which projects a larger surface area than material strip  205  projects by itself, and which can, therefore, catch the air flow more efficiently than that being caught by the material strip alone. 
         [0022]    However, in another embodiment (not shown) wind screen  204  is not used and apparatus  202 ,  203  and  204  do not appear. Flexible material  205  is suspended solely from axel  201  and is lofted by air flow directly. In this other embodiment, as well as the embodiment of  FIG. 2 , stones or holes or other obstructions in the roadway during backing-up are not an issue because the flexible material merely accommodates the obstruction by flexing over or around it (e.g., a rock) or sliding through it (e.g., a pothole). ( 211   FIG. 3  shows embodiment  200   a , which is the apparatus of  FIG. 2  from the same rear viewpoint but under conditions of a forward moving truck. (The “a” designation is used merely to suggest that  FIG. 3  is the same as  FIG. 2  but under a state of forward motion of the truck. The dimensions of the components look shorter in this view because the components have been raised or lofted because the truck is moving forward, but the components are otherwise identical to those of  FIG. 2 ). In this view, material  205   a  is the same as material  205 , but lofted so that a clearance of distance “D” is achieved between the end of material  205   a  and roadway  104 . Wind-screen  204   a  is suspended by flexible supports  202   a  and  203   a  from axel  201 , as in  FIG. 2 . The bracket at the far left of  FIG. 3  is merely to indicate that all that is shown in that view is within  FIG. 3 . 
         [0023]    Referring to  FIG. 4 , the components of  FIG. 3  are shown in side view. Axel  201  is shown on end. Support  203   a  is shown on edge, connecting to wind-screen  204   a  which is also shown on edge. Conductive strip  205   a  is shown on edge being supported by wind-screen  204   a . Clearance “D” is shown in this Fig. as well, and is the same distance “D” shown in  FIG. 3 . Wind force is directed from the left of the diagram, as shown, as truck  100  moves forward, to the left side in  FIG. 1 . Wind-screen  204   a  may typically be sized with dimensions of three feet by one foot, but the dimensions can vary depending on the size and shape of the truck under which it is attached. The material from which the wind-screen is made can also vary; it needs to be lightweight and weather-resistant. A light, stiff plastic material or other similar material would he suitable for this purpose. 
         [0024]    In operation, referring to  FIGS. 1-4 , assuming truck  100  was carrying embodiment  200 / 200   a  under its carriage rather than chain  105 , as truck  100  drives to the left and picks up speed, the wind or breeze created underneath the truck by virtue of its velocity directs wind force against windscreen  204  which causes it to rotate around an axis co-linear with axel  201 . That rotation lifts flexible conductive material  205  into the air and creates a clearance of dimension “D” between the end of the conductive material and road surface  104 . This clearance reduces the wear opportunities which otherwise would occur upon conductive material  205 , and greatly enhances the life of this material. Otherwise, friction forces from road surface  104  being in contact with conductive material  205  while the truck is driving down the road would wear away the material until it no longer made contact with the road surface whereby its effectiveness in grounding the static electricity charge on truck  100  would be substantially if not completely reduced. 
         [0025]    Thereafter, when truck  100  comes to a stop, the wind forces on structure  204  are reduced to zero and the force of gravity causes material  205  to make contact with roadsurface  205  (with the Earth). This happens prior to the truck completely stopping and well-prior to anyone inside the truck opening door  106  and disembarking. This is important because it prevents the possibility of the truck driver/passenger from experiencing a static electricity shock, since the grounding from the truck is automatic, instantaneous and in place before the truck occupants open the door (the door is not opened until the truck stops and the static discharge contact between material  205  and roadway  104  is made just as the truck is stopping and before the door is opened.) A motion-limiting strap (not shown) could be attached between windscreen  204   a  and the underside of the chassis of the truck so that the downward displacement of windscreen  204   a  is limited to a safe clearance above the roadway. It is not important, or desirable, for windscreen  204   a  to contact the roadway when the vehicle is stopped; it is important only for the flexible conductive strip to contact the roadway when the vehicle is stopped. 
         [0026]    In the embodiment earlier mentioned in which apparatus  202 ,  203  and  204  are not used, where material  205  is suspended only by axel  201 , the fluttering material  205  during vehicle forward motion may possibly still come in contact with the roadway intermittently, depending on vehicle speed, weather conditions, etc. But, this is not equivalent to, and a vast improvement over, the constant wear of the chain discharge mechanism of the prior art. However, if one were to use the embodiment with windscreen  204 , this may be an improvement because windscreen  204  may add loft stability to the fluttering discharge material, thereby reducing frequency of contact between material and roadway or eliminating it completely. 
         [0027]      FIG. 5  depicts an embodiment which addresses a backing-up situation where there may be obstructions or potholes in the roadway. In the prior Figs., this was not an issue because material  205  is flexible and therefore would not get locked on a stone lying on the roadway, or in a pot hole formed in the roadway. The flexible material would simply flex around the obstruction or within the hole. However, if other embodiments of the present invention are utilized, such as a conductive rod or spring, although it would not have an issue in proper functioning when moving forward, it could jam against a rock or lodge in a pot hole when the truck is moving backward. In  FIG. 5 , electrically-conductive rod or spring  505  is depicted which, in this view, has a similar thickness appearance to that of conductive strip  205   a . However, although rod or spring  505  is flexible, it is not as flexible as material  205 . Therefore, a large curve is formed in the rod or spring to enable it to ride over rocks in the roadway and to slide across potholes in the roadway. 
         [0028]    An alternative embodiment would connect rod  505  to a conductive rotatable metallic wheel (not shown) where the wheel is in contact with roadway  104  and has the ability to roll-over rocks and roll across potholes when the truck is moving in a reverse direction. 
         [0029]    Other more elaborate controls can be instituted as well. A magnetic mechanism (not shown) which directs a magnetic field from the under chassis to the metal rod can be fashioned, where such field is automatically energized anytime the transmission of the truck is placed in reverse gear. That magnetic force can be used to lift the rod so that it avoids all contact with the roadway when the truck is moving in reverse, Additional controls can be instituted, utilizing the magnetic mechanism, where the rod is held in place above the roadway when the transmission of the truck is placed in any forward gear. Thus, the rod can be held off the ground by magnetic force during forward motion of the truck as well. The critical factor is that contact is made with the roadway no later than the opening of the doors of the truck, and an interlock mechanism with the doors can be used for that purpose, where any door opening causes an over-ride to the energizing of the magnetic mechanism which, in turn, causes the metal rod to fall to the ground. However, these are more elaborate and more expensive controls, and the windscreen technique embodiment and/or the flexible conductive mesh without the windscreen embodiment can perform satisfactorily. 
         [0030]    While several illustrative embodiments of the present invention have been shown and described, numerous variations and alternative embodiments may occur to those skilled in the art. Such variations and alternative embodiments are contemplated, and can be made without departing from the spirit and scope of the present invention as defined in the appended claims.