Abstract:
Exemplary surface debris removal systems and methods are operable to remove debris from a signal transmitting/receiving surface. An embodiment provides power to, and then removes power from, a conductive memory wire that is secured to a moveable portion of a two-position snap spring. In response to providing the power to the conductive memory wire, a length of the conductive memory wire decreases so that the moveable portion of the two-position snap spring is pulled from an extended position to a retracted position. When power is removed from the conductive memory wire, the moveable portion of the two-position snap spring moves from the retracted position to the extended position. In response to the moving of the moveable portion of the two-position snap spring from the retracted position to the extended position, an energy is generated and transferred to the surface that dislodges the debris from the surface.

Description:
BACKGROUND 
     Optical and electronic devices may accumulate debris that interferes with the intended purpose of the devices. Debris may include snow, ice, dirt, dust, or other matter. Such debris may accumulate on a signal-receiving or signal-transmitting surface that is exposed to an ambient environment. For example, a satellite antenna, also referred to as a satellite dish, may accumulate snow that blocks or interferes with the reception or transmission of communication signals. Debris accumulating on the surface of a mirror may degrade reflectivity of the mirror. Similarly, debris on a lens surface may degrade and/or distort transmissivity of the lens. Accordingly, when performance of the device is degraded due to debris accumulation on an exposed surface, the surface will require removal of the debris. In some situations, the surface of the device may be periodically cleaned so as to reliably maintain the performance characteristics of the device. 
     Debris may be removed manually from the surface of the device. However, there may be an undesirable time delay while service personnel are dispatched to perform the manual task of debris removal. And, the attendant labor charges may be relatively expensive. 
     In other situations, the debris may be removed from the surface of the device using a debris-removing device. However, such debris removal devices require a source of power. Accordingly, the initial cost of the electronic debris removal device, the cost of the power source, and the associated operating costs of such electronic debris removal devices and their associated power source may be relatively expensive. 
     Accordingly, there is a need in the arts for improved surface debris removal devices and methods. 
     SUMMARY 
     Systems and methods of debris removal from a surface of a device are disclosed. An exemplary embodiment is operable to remove debris from a signal transmitting/receiving surface. An embodiment provides power to, and then removes power from, a conductive memory wire that is secured to a moveable portion of a two-position snap spring. In response to providing the power to the conductive memory wire, a length of the conductive memory wire decreases so that the moveable portion of the two-position snap spring is pulled from an extended position to a retracted position. When power is removed from the conductive memory wire, the moveable portion of the two-position snap spring moves from the retracted position to the extended position. In response to the moving of the moveable portion of the two-position snap spring from the retracted position to the extended position, an energy is generated and transferred to the surface that dislodges the debris from the surface. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Preferred and alternative embodiments are described in detail below with reference to the following drawings: 
         FIG. 1  is a block diagram of an embodiment of a surface debris removal system; 
         FIGS. 2A and 2B  are perspective views of an exemplary embodiment of the mechanical system; 
         FIGS. 3A-3C  illustrate a moveable portion of a two-position snap spring in an extended position and in a retracted position; 
         FIG. 4  illustrates an exemplary vibration-based embodiment of the surface debris removal system coupled to the STR device using one or more device couplers; 
         FIG. 5  illustrates an impact-based embodiment of the surface debris removal system coupled to the STR device using one or more device couplers; 
         FIG. 6  illustrates an embodiment with a spring element in series with a portion of the conductive memory wire; and 
         FIG. 7  illustrates an embodiment with a mechanical actuator that causes the moveable portion of the two-position snap spring to snap from the retracted position to the extended position. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a block diagram of an embodiment of a surface debris removal system  100  implemented coupled to a signal transmitting/receiving (STR) device  102 . Embodiments of the surface debris removal system  100  comprise a mechanical debris removal device  104 , a processor system  106 , an optional debris sensor  108 , an optional timer  110 , an optional temperature sensor  112 , and an optional interface device  114 . The mechanical debris removal device  104  comprises a power source  116 , an electronic actuator  118 , and a mechanical system  120 . The surface debris removal system  100  is physically coupled to the STR device  102  using one or more device couplers  122 . 
     The STR device  102  includes at least one signal transmitting/receiving (STR) surface  124  that accumulates undesirable debris  126 . Contact surface forces between the STR surface  124  and the debris  126  allow the debris  126  to accumulate and adhere to the STR surface  124 . For example, frictional forces may permit dust or snow to accumulate and adhere to the STR surface  124 . If liquids are associated with the debris  126 , such as when snow initially comes into contact with a relatively warm STR surface  124  and melts, surface tension may allow the formed water to adhere to the STR surface  124 . At some point, the water may freeze and adhere to the STR surface  124 , thus allowing additional snow to accumulate on the STR surface  124 . The various forces and physical phenomena that allow debris  126  to accumulate and adhere to the STR surface  124  are generally referred to herein as contact surface forces. 
     When the debris  126  is to be removed, the processor system  106  communicates a control signal to the electronic actuator  118 . The control signal is generated in response to some particular event which is associated with accumulation of the debris  126  on the STR surface  124 . 
     In an exemplary embodiment, the electronic actuator  118  actuates the power source  116  so that electrical power is provided to the mechanical system  120 . In other embodiments, the electronic actuator  118  directly actuates the mechanical system  120 . Upon actuation, the mechanical system  120  imparts physical energy  128  to the STR device  102 . The physical energy  128  may be directly imparted to the STR device  102  by the mechanical system  120 , or may be transmitted to the STR device  102  via the one or more device couplers  122 . 
     The physical energy  128  causes a shaking motion, a vibration, or the like, on the STR surface  124  such that the debris  126  falls from the STR surface  124 . That is, the imparted physical energy  128  causes a movement of the STR surface  124  that is sufficient to cause gravity to overcome the contact surface forces that hold the debris  126  on the STR surface  124 . 
     In some embodiments, the power source  116  may be a self-contained source of power, such as a battery, a solar cell, a wind generator, or combination thereof. In other embodiments, the power source  116  may be a switch device or the like that is coupled to an external source of power. 
     Some embodiments employ the debris sensor  108  to detect accumulation of the debris  126  on the STR surface  124 . In response to detecting a threshold amount of debris  126 , the debris sensor  108  communicates a signal to the processor system  106 . In response to receiving a signal from the debris sensor  108 , the processor system  106  generates the control signal that actuates the electronic actuator  118 . The debris sensor  108  may be any suitable sensor that is configured to sense the presence of the debris  126  on the STR surface  124 . Non-limiting examples of the debris sensor  108  include, but are not limited to, an optical sensor, a weight sensor, a sonic sensor, and/or a pressure sensor. Multiple debris sensors  108  may be used in some embodiments. 
     Some embodiments employ the timer  110  to periodically communicate a signal to the processor system  106 . In response to receiving a signal from the timer  110 , the processor system  106  generates the control signal that actuates the electronic actuator  118 . The timer  110  may be any suitable timer device that is configured to periodically communicate a signal to the processor system  106 . In some embodiments, the timer  110  may be integrated into the processor system  106 . 
     Some embodiments employ the temperature (temp) sensor  112  to detect a temperature of the STR device  102 , a temperature of the STR surface  124 , an ambient temperature, and/or another temperature of interest. In response to detecting a threshold temperature, the temperature sensor  112  communicates a signal to the processor system  106 . In response to receiving a signal from the temperature sensor  112 , the processor system  106  generates the control signal that actuates the electronic actuator  118 . The temperature sensor  112  may be any suitable temperature sensor. Multiple temperature sensors  112  may be used in some embodiments. 
     Some embodiments employ the interface device  114 . The interface device  114  is configured to receive a signal on connection  130  that is generated by another device (not shown). In response to receiving a signal on the connection  130 , the interface device  114  communicates a signal to the processor system  106 . In response to receiving a signal from the interface device  114 , the processor system  106  generates the control signal that actuates the electronic actuator  118 . Alternatively, the interface device  114  may receive a wireless signal from the external device, such as an infrared signal or a radio frequency (RF) signal. 
     The interface device  114  may be any suitable interface that is configured to receive a signal from another device. For example, an external sensor (not shown) that is configured to detect accumulation of the debris  126  on the STR surface  124 , detect temperature, or sense another parameter, may communicate the signal to the interface device  114 . Multiple interface devices  114  may be used in some embodiments. 
     The interface device  114  may be communicatively coupled to a set top box (STB) or other consumer appliance that is configured to communicate the signal to the interface device  114 . In some embodiments, the STB or other consumer appliance is configured to communicate the signal to the interface device  114  in response to a command from a user. 
     For example, the user may be watching programming on their television during a snow storm. At some point, an accumulation of snow on the STR surface  124  may interfere with signal reception. The user may then cause the STB to communicate the signal to the interface device  114  so as to dislodge the snow from the STR surface  124 . 
     Alternatively, or additionally, the STB may be communicatively coupled to a service center or the like where an operator, service technician, or other person may cause the STB or other consumer appliance to communicate the signal to the interface device  114 . For example, the user may call into the service center to complain of bad signal reception on their television. The service technician can then remotely operate the STB or other consumer appliance to communicate the signal to the interface device  114  so as to dislodge any accumulated debris  126 . If the debris  126  was the cause of the poor signal reception, the user and/or the service technician would then see a noticeable improvement in the signal reception. 
     Alternatively, or additionally, the interface device  114  may be configured to receive the signal from a hand-held remote that is controlled by the user. For example, a special actuator, button, or the like may reside on the hand-held remote. In response to actuation by the user, the hand-held remote communicates a wireless signal to the interface device  114 . 
     Some embodiments may employ one or more of the debris sensor  108 , the timer  110 , the temperature sensor  112 , and/or the interface device  114 . Further, one or more of the debris sensor  108 , the timer  110 , the temperature sensor  112 , and/or the interface device  114  may reside externally to the debris removal system  100  as a separate component. 
       FIGS. 2A and 2B  are perspective views of an exemplary embodiment of mechanical system  120 .  FIG. 2A  shows an exterior view of the exemplary embodiment of the mechanical system  120 .  FIG. 2B  shows an interior view of selected elements of the exemplary embodiment of the mechanical system  120 . The exemplary embodiment of the surface mechanical system  120  includes a body portion  202  and a two-position snap spring  204 . 
     The body portion  202  includes a first end portion  206 , a hollow middle portion  208 , and a second end portion  210 . In this exemplary embodiment, the two-position snap spring  204  is secured to the first end portion  206 . The power source  116  is a switch or other suitable electronic actuator that is coupled to a source of power  212  via connection  214 . The power source  116  is secured to body portion  202 , such as at the second end portion  210 . The device coupler  122  is also secured to the body portions, such as the middle portion  208 . 
     The two-position snap spring  204  comprises a moveable portion  216  and a securing portion  218 . The securing portion  218  is secured to the first end portion  206  of the body portion  202 . In this exemplary embodiment, the two-position snap spring  204  is a generally conic structure, or cup-shaped structure, made of an elastically deformable material, such as metal or plastic. The conic structure of the two-position snap spring  204  permits the moveable portion  216  of the two-position snap spring  204  to be in an extended position, as illustrated in  FIGS. 2A and 2B , and in a retracted position. 
     The mechanical system  120  is illustrated as generally cylindrical in shape. In other embodiments, the mechanical system  120  may have other designed shapes. Further, the first end portion  206 , the hollow middle portion  208 , and/or the second end portion  210  may have other shapes. The mechanical system  120  may be made of any suitable material that is substantially rigid, such as metal, plastic, or the like. 
       FIG. 2B  illustrates a conductive memory wire  220  extending through the body portion  202  of the mechanical system  120 . A first end portion  222  of the conductive memory wire  220  is secured to the second end portion  210  of the body portion  202 . Further, the first end portion  222  of the conductive memory wire  220  is electrically coupled to the power source  116 . A second end portion  224  of the conductive memory wire  220  is secured to the moveable portion  216  of the two-position snap spring  204 . 
     In the illustrated exemplary embodiment, the first end portion  206  is a disk with an aperture for passage of the conductive memory wire  220  there through. Thus, movement of the conductive memory wire  220  is not inhibited by the first end portion  206 . One or more optional apertures  226  may be provided for the transfer of air between the two-position snap spring  204  and the body portion  202 . In alternative embodiments, the first end portion  206  may be formed as a rigid ring or other structure. 
       FIGS. 3A-3C  illustrate the moveable portion  216  of the two-position snap spring  204  in the extended position  302  and in the refracted position  304 . Initially, the moveable portion  216  of the two-position snap spring  204  is in the extended position  302 . The conductive memory wire  220  is at or near an ambient temperature, and is in an elongated state. 
     The conductive memory wire  220  is made of a conductive material that shrinks as it is heated. Here, when current passes through the conductive memory wire  220  upon actuation of the power source  116 , resistive losses caused by current passing through the conductive memory wire  220  heats the conductive memory wire  220 . As the temperature of the conductive memory wire  220  increases, the length of the conductive memory wire  220  tends to decrease as the material of the conductive memory wire  220  shrinks. 
     Initially, since the conductive memory wire  220  is secured to the moveable portion  216  of the two-position snap spring  204 , the tension of conductive memory wire  220  induced by shrinkage of the heating material begins to exert a pulling force on the moveable portion  216  of the two-position snap spring  204 . At some point, the tension of the conductive memory wire  220  causes the moveable portion  216  to elastically, and rapidly, deform from the extended position  302 , illustrated in  FIG. 3A , to the retracted position  304 , illustrated in  FIG. 3B . 
     The moveable portion  216  of the two-position snap spring  204  tends to rapidly move from the extended position  302  to the retracted position  304  with a snap-like action. That is, very little physical displacement of the moveable portion  216  is required to cause the moveable portion  216  of the two-position snap spring  204  to snap from the extended position  302 , as illustrated in  FIG. 3A , to the retracted position  304 , as illustrated in  FIG. 3B . In the exemplary embodiment illustrated in  FIG. 3B , the conductive memory wire  220  flexes to accommodate movement of the moveable portion  216  of the two-position snap spring  204  from the extended position  302  to the retracted position  304 . 
     The power provided to the conductive memory wire  220  is terminated by a second actuation of the power source  116 . With the removal of the current passing through the conductive memory wire  220 , the conductive memory wire  220  begins to cool. This cooling of the conductive memory wire  220  tends to cause the material of the conductive memory wire  220  to expand. The expanding material of the conductive memory wire  220  tents to elongate the conductive memory wire  220 . The elongation of the conductive memory wire  220  tends to cause a pushing force that is exerted on the moveable portion  216  of the two-position snap spring  204 . At some point, the exerted force causes the moveable portion  216  of the two-position snap spring  204  to elastically, and rapidly, deform from the retracted position  304 , as illustrated in  FIG. 3B , to the extended position  302 , as illustrated in  FIG. 3C . This movement of the moveable portion  216  from the retracted position  304  to the extended position  302  occurs in a rapid, snap-like manner. 
       FIG. 4  illustrates a vibration-based embodiment of the surface debris removal system  100  coupled to the STR device  102  using one or more device couplers  122 . The snap-like action of the moveable portion  216  of the two-position snap spring  204  from the extended position  302  to the retracted position  304  induces a motion of the mechanical system  120 . Repeated application power to the conductive memory wire  220  causes the moveable portion  216  of the two-position snap spring  204  to repeatedly move between the extended position  302  and the retracted position  304 , thereby inducing a vibratory motion of the mechanical system  120 . Vibratory motion is caused by the inertia of the moveable portion  216  of the two-position snap spring  204  as it moves with a snap-like motion between the extended position  302  and the retracted position  304 . In some embodiments, mass may be added to the moveable portion  216  of the two-position snap spring  204 . The energy of the induced vibratory motion of the mechanical system  120  is transferred, via the one or more device couplers  122 , to the STR device  102  such that the accumulated debris  126  is dislodged from the STR surface  124 . 
       FIG. 5  illustrates an impact-based embodiment of the surface debris removal system  100  coupled to the STR device  102  using one or more device couplers  122 . The moveable portion  216  of the two-position snap spring  204  comes into physical contact with the STR device  102  at a selected impact point  502  when the moveable portion  216  is in the extended position  302 . The location of the impact point is a design choice, and the amount of impact, is controlled by location and/or orientation of the one or more device couplers  122 . 
     The snap-like action of the moveable portion  216  as it moves from the retracted position  304  to the extended position  302  results in an abrupt, physical impact-type contact at the impact point  502 . The impact at the impact point  502  induces a transfer of energy from the mechanical system  120  to the STR device  102  due to the inertia of the moveable portion  216  as it moves with the snap-like motion from the retracted position  304  to the extended position  302 . The induced impact energy to the STR device  102  causes the accumulated debris  126  to be dislodged from the STR surface  124 . In some embodiments, mass may be added to the moveable portion  216  of the two-position snap spring  204  to increase the impact energy. 
       FIG. 6  illustrates an embodiment with a spring element  602  in series with a portion of the conductive memory wire  220 . The spring element  602  may optionally be electrically conductive. 
     When the moveable portion  216  of the two-position snap spring  204  snaps from the retracted position  304  to the extended position  302 , the spring element  602  allows continued movement of the moveable portion  216  of the two-position snap spring  204  beyond the linear extent of the conductive memory wire  220 . Thus, the linear extent of the conductive memory wire  220  does not limit the movement of the moveable portion  216  of the two-position snap spring  204  when it snaps from the retracted position  304  to the extended position  302 . 
     When power is applied to the conductive memory wire  220  to cause the moveable portion  216  of the two-position snap spring  204  to move from the extended position  302  to the retracted position  304 , the spring element  602  may optionally maintain the conductive memory wire  220  in a straight line orientation, thereby avoiding bending of the conductive memory wire  220 . 
       FIG. 7  illustrates an embodiment with a mechanical actuator  702  that causes the moveable portion  216  of the two-position snap spring  204  to snap from the retracted position  304  to the extended position  302 . The mechanical actuator  702  moves a lever arm  704  in response to receiving a control signal from the processor system  106  ( FIG. 1 ) via connection  706 . In this embodiment, the lever arm  704  engages the moveable portion  216  of the two-position snap spring  204  to move from the extended position  302  to the retracted position  304 . 
     In this embodiment, the removal of power to the conductive memory wire  220  causes the expansion of the material of the cooling conductive memory wire  220 . However, the expanding material of the conductive memory wire  220  does not generate sufficient force to initiate the snapping of the moveable portion  216  of the two-position snap spring  204  from the retracted position  304  to the extended position  302 . Accordingly, at some desired time, the mechanical actuator  702  is actuated such that the lever arm  704  engages and pushes the moveable portion  216  of the two-position snap spring  204 , wherein the moveable portion  216  snaps from the refracted position  304  to the extended position  302 . 
     In some embodiments, the debris removal system  100  may reside in, or be integrated with, another electronic device. For example, the debris removal system  100  may reside in or be integrated as a component of the STB or other consumer appliance. 
     It should be emphasized that the above-described embodiments of the debris removal system  100  are merely possible examples of implementations of the invention. Many variations and modifications may be made to the above-described embodiments. All such modifications and variations are intended to be included herein within the scope of this disclosure and protected by the following claims.