Abstract:
A wheelchair lift mounted on the rear of an automobile for transporting a wheelchair, scooter or other mobility device includes two or more sets of sensors. A first set of sensors is located at the distal ends of the wheelchair lift platform for use when the platform is horizontal. A 2nd set of sensors is located on the base of the wheelchair lift for use when the platform is folded vertically. The sensors alert a driver to the presence of objects in close proximity to the rear of the vehicle when driven in reverse. They switch automatically activates the base sensors when the platform is folded and the platform sensors when the platform is horizontal.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. Provisional Application Ser. No. 61/674,011 filed Feb. 20, 2012 the contents of which are hereby incorporated by reference in its entirety. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED 
     Not Applicable 
     RESEARCH OR DEVELOPMENT 
     Not Applicable 
     REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER 
     Not Applicable 
     PROGRAM LISTING COMPACT DISC APPENDIX 
     Not Applicable 
     FIELD 
     The present invention relates to systems and apparatuses for wheelchair lift devices for attachment to the back of an automobile for transporting wheelchairs and similar devices. More particularly, the invention provide systems and apparatuses for rear mounted wheelchair lifts that include proximity sensors. 
     BACKGROUND 
     electronically operated hitch mounted wheelchair lifts have been available for a number of years and permit the user of a scooter, wheelchair or other mobility device to be mechanically lifted entered to an automobile or transportation. 
     A common probably associated with the use of hitch mounted wheelchair lifts is an automobile drivers inability to ascertain how far back the rear wheelchair lift protrudes from the back of the automobile. This results in a large number of accidents where the driver this judges distance and a wheelchair lift impinges upon a solid object causing damage. 
     It has also become common for automobile manufacturers to include a rear mounted proximity sensor or video camera to assist a driver in driving a car in reverse with out colliding with an object, unseen by the driver. Such proximity sensors and video cameras have become highly desirable features on an automobile. Unfortunately, the attachment of a rear mounted wheelchair lift frustrates the purpose of such devices because a proximity sensor may not take into account the distance between an object behind the car and a wheelchair lift that protrudes from the vehicle itself. 
     Further frustrating the use of proximity sensors or cameras with a wheelchair lift is the fact that wheelchair lifts typically translate between 2 or more configurations. For example, a wheelchair lift usually incorporates a platform onto which a wheelchair, scooter or other mobility device is rolled on to. Once a wheelchair is rolled onto the platform, it is lifted into the air for transport. However, when a wheelchair is not being transported, it is common for the platform to fold up into a more compact configuration. When I platform is horizontal. It occupies significantly more area than when it is folded up vertically. Any proximity sensor or camera mounted on the rear of an automobile does not take into account either configuration. 
     In view of the foregoing, there is a need to provide a proximity sensor that may be used in conjunction with a rear-mounted wheelchair lift for an automobile. Furthermore, it is desirable to provide a proximity sensor that may be used in conjunction with a rear-mounted wheelchair lift for an automobile that is effective for all the configurations of the wheelchair lift. 
     SUMMARY 
     Accordingly, the primary object of the present invention is to provide a Wheelchair lift that may be mounted on the rear of an automobile and incorporates a proximity sensor or that may accurately indicate to a driver the presence of an distance from any objects behind the automobile and close to the wheelchair lift. The present invention is directed to a hitch mounted wheelchair lift having backup sensors, including both platform sensors and base sensors, for detecting and alerting an automobile operator to an approaching rear obstruction for the purpose of preventing collisions in damage to the lift platform, a scooter or wheelchair carried on the platform, as well as the obstruction. 
     The wheelchair lift may have components that wirelessly communicate, or that are connected by wiring. When wiring is used, quick disconnect devices for connecting and disconnecting the associated wiring may be used for easy attachment and detachment as well as for safety reasons. 
     The backup sensors communicate with a visual display and/or speakers or audio devices that may alert the driver, and communicate to him or her the presence of an proximity to obstructions or solid object to the rear of an automobile and wheelchair lift. 
     Visual displays are increasingly common for rear placement on an automobile. They driver places the transmission in reverse, a camera provides a video feed to a display for the driver. In addition, it is also common for proximity sensors to initiate a beeping sound when an object is detected to the rear of an automobile. Often, a repeated beeping is emitted from a speaker, and the frequency of the beeps increases as the distance to an object decreases. 
     In the present invention, similar devices are used and are incorporated into a wheelchair lift. 2types of sensors are utilized: a first sensor or sensors may be placed on a distal ends of the wheelchair platform; a second sensor or sensors may be placed on the distal end of the base of the wheelchair lift. When the platform is horizontal, the sensors at the distal end of the platform are used to detect obstructions to the rear of the automobile. When the platform is folded into the horizontal position. The sensors on the base of the wheelchair lift are used for proximity detection. Switching may occur automatically between the 2 types of sensors. Audio and visual devices may be used to communicate to a driver the presence of an proximity to any obstructions or solid object to the rear of the vehicle. 
     It is therefore an object of the present invention to provide a wheelchair lift having sensors for detecting the presence of and distance to objects to the rear of an automobile and wheelchair lift accurately when the lift platform is in either the horizontal or the vertical position. 
     These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims. There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A more complete understanding of the present invention, and the attendant advantages and features thereof, will be more readily understood by reference to the following detailed description when considered in conjunction with the accompanying drawings wherein: 
         FIG. 1  is a perspective view of a wheelchair lift with a platform in the horizontal position of the prior art; 
         FIG. 2  is a rear view of a wheelchair lift with a platform in the horizontal position in accordance with the principles of the invention; 
         FIG. 3  is a rear view of a wheelchair lift with the platform in the vertical position in accordance with the principles of the invention; 
         FIG. 4  is a side view of a wheelchair lift with the platform and the horizontal position in accordance with the principles of the invention; 
         FIG. 5  is a side view of a wheelchair lift with the platform in the vertical position in accordance with the principles of the invention; 
         FIG. 6  is a side view of an alternative embodiment of a wheelchair lift with a platform in the horizontal position in accordance with the principles of the invention. 
     
    
    
     DETAILED DESCRIPTION 
     Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. 
       FIG. 1  shows a wheelchair lift  2  of the prior art. The wheelchair lift to includes a hitch mount  4  for removable attachment to the trailer hitch receiver on an automobile. The hitch mount  4  may be designed for compatibility with any particular trailer hitch receiver back considerably support the lift platform  2 . The hitch mount  4 . 
     Referring to  FIGS. 2-5 , the wheelchair lift  10  may include a hitch mount  12  for removable attachment to a trailer hitch receiver on an automobile. The hitch mount  12  may be designed for compatibility with any particular trailer hitch receiver that may suitably support wheelchair lift  10 . The hitch mount  12  may be in secured and/or adjustable connection with elevator  14 . Base  15  may be located at the bottom of elevator  14 . The distance of base  15  from the ground may be increased and decreased by mechanical operation of the elevator  14 , which uses telescoping or other means to translate the height of the base from flush with the ground to an elevated position during transport. Base  15  may be pivotally connected to platform  16 . Platform  16  may be pivoted through about 90° from a horizontal position perpendicular to the elevator  14  as shown in  FIGS. 2 and 4  to a vertical position as shown in  FIGS. 3 and 5  parallel to the elevator  14 . Mechanical operation of elevator  14  may allow the base  15  and platform  16  to be lowered such that the platform  16  is flush with the ground. 
     The wheelchair lift  10  may include one or more platform sensors  18  located at the distal end  17  of the platform  16 . Platform sensors  18  may be secured to the platform  16  using any sufficient securing means known in the art, including, but not limited to, bolts, adhesives, screws, brackets, tape or the like. Platform sensors  18  may be infrared sensors, lidar sensors, capacitance sensors, sonar sensors or other sensors capable of determining when a solid object is within a proscribed distance from the distal end  17  of the platform  16 . Optionally, platform sensors  18  may be cameras or video devices or sensors. The platform sensors  18  may be directed away from the base  15  and the elevator  14  such that they are directed rearward and away from an automobile to which the hitch mount  12  is attached. In the embodiment shown in  FIGS. 1-4 , four platform sensors  18  are affixed to the distal end  17  of the platform  16 . Optionally, a wheelchair lift in accordance with the principles of the invention may have as few as one platform sensor  18  or five or more platform sensors  18 . 
     Base sensors  19  may secured to the distal end  23  of the base  15 . Platform sensors  19  may be secured to the base  15  using any sufficient securing means known in the art, including, but not limited to, bolts, adhesives, screws, brackets, tape or the like. Base sensors  19  may be infrared sensors, lidar sensors, capacitance sensors, sonar sensors or other sensors capable of determining when a solid object is within a proscribed distance from the distal end  23  of the base  15 . Optionally, Base sensors  19  may be cameras or video devices or sensors. The base sensors  19  may be directed away from the elevator  14  such that they are directed rearward and away from an automobile to which the hitch mount  12  is attached. In the embodiment shown in  FIGS. 2-5 , two base sensors  19  are affixed to the distal end  23  of the base  15 . Optionally, a wheelchair lift in accordance with the principles of the invention may have as few as one base sensors  19  or three or more base sensors  19 . 
     When the platform  16  is perpendicular to the elevator  14  and parallel to the ground, platform sensors  18  may detect when a solid object comes within the prescribed distance. When the platform  16  is parallel to the elevator  14  and perpendicular to the ground, platform sensors  18  may be directed upward and base sensors  19  may detect when a solid object comes within the proscribed distance. 
     The wheelchair lift  10  may include a switch  21  that controls the platform sensors  18  and the base sensors  19 . Switch  21  made attacks when platform  16  is in the horizontal position and activate platform sensors  18 , while simultaneously deactivating base sensors  19 . When platform  16  is folded into the horizontal position parallel to the elevator  14 , the switch  21  may deactivate sensors  18  and activate sensors  19 . In this manner, the appropriate sensors are automatically selected for use in detecting the proximity of solid objects behind an automobile. 
     A wheelchair lift in accordance with the principles of the invention may also include a visual display  28  and/or a speaker  22 . Optionally, only one of a display  28  and a speaker  22  may be provided. When any of the sensors  18  and  19  detect a solid object within the proscribed distance a signal may be sent to the visual display  28  and/or a speaker  22 . A speaker  22  may provide a chime or be to alert a driver that the rear of the vehicle is approaching a solid object. Optionally, the speaker  22  may provide a repeating series of sounds which may increase or decrease depending upon the proximity of objects behind an automobile and detected by the sensors. Optionally, speaker  22  may provide a voice stating the distance of any object behind the automobile as detected by the sensors  18  and  19 . 
     A visual display  20  may similarly provide information to the driver of an automobile to which the wheelchair lift is attached by displaying alphanumeric information, for example, the visual display  20  may display the distance of an object from the sensors  18  or  19  and feet, meters, or the like. Where the sensors  18  and  19  comprise a video camera or video sensor, the visual display  20  may be a video screen displaying the image procured by the video camera or video sensor. Those skilled in the art will appreciate that sensors  18  and  19  are very similar to the sensors that are quickly becoming common on the rear of automobiles to prevent accidental collisions. 
     Platform sensors  18 , base sensors  19 , switch  21 , visual display  20  and speaker  22  may be an electronic signal communication with one another in any of a variety of series or patterns using various methodologies known in the art. In the embodiment shown in  FIGS. 2-5 , the various components are connected by means of wiring. However, it may be desirable for one or more of the components to be an wireless communication. Wireless communication may be preferable to minimize the possibility of entanglement of wiring and may obviate the need for quick release devices Incorporated into the wiring as is commonly done with vehicles today. 
     In the embodiment shown in  FIGS. 2-5 , platform sensors  18  are in electronic signal communication with switch  21  by means of wires  60 . Similarly, base sensors  19  are in electronic signal communication with switch  21  by means of wires  62 . Switch  21  may be an electronic signal communication with a sensor module  24  by means of wires  28 . Sensor module  24  may relay any electronic signals from the sensors  18  or  19  to a visual display  20  and or a speaker  22  via switch  21 . 
     The wheelchair lift  10  includes moving parts. As a result, the distances from the various components may vary as the platform  16 , base  15  and elevator  14 . All moved in relation to one another. As a result, access slack may develop in one or more of the wires. It may therefore be desirable to include one or more Springs  38  to collect slack in one or more wires to prevent tangling or other damage. Optionally, it may be desirable to use sensors, switches, module and other components that may communicate wirelessly. This may result in a wheelchair lift being more durable and less easily damaged. 
     Sensor module  24  may be in wireless communication with a visual display  20  and or a speaker  22  and, as in this embodiments, may be Incorporated into the lift control box  26 , which may house various components of the elevator  14 . In this embodiment, however, sensor module  24  is an electronic signal communication by means of wire  30  which includes a quick disconnect  32 , as is commonly used in trailers attached to automobiles. Similarly, in the wheelchair lift  10  shown in the figures, power is supplied to the various components by power cord  34 , which may draw power from the backup or reverse light and supply it to power cord  36  to which it is connected by means of quick release  32 . Sensor module  24  may then distribute power to switch  21  and sensors  18  and  19 . Will when components capable of communicating wirelessly are utilized, the various components may have individual power sources, such as for example a battery. Optionally, wirelessly communicating components may draw power from power cords. 
     Switch  21  may operate by any of a variety of means known in the art. Switch  21  operates such that electronic signals may be received from base sensors  19 . When platform  16  is in the horizontal position perpendicular to the ground. Switch  21  also may operate such that no signal is received from base sensors  19  when platform  16  is in the horizontal position parallel to the ground. When the platform  16  is a horizontal position switch  21  may operate to only receive signals from platform sensors  18 . Magnetic switches, liquid mercury switches or even very simple mechanical switches they all be utilized by switch  21  to activate and deactivate sensors  18  and  19  depending upon the position of the platform  16 . 
     Visual display  20  and speakers  22  may be an wireless or wired electronic signal communication with the sensor module and/or the switch  21  and/or the sensors  18  to  19 . Optionally, sensor module  24  may be integrated with visual display  20  and/or speaker  22 . Optionally, a single component may be utilized and placed in close proximity to the operator or driver of the vehicle, the single component, including visual displays and/or audio displays as well as any circuitry required. The components proximal to the operator of the vehicle may have their own power supply or may be supplied power from the automobile, such as through the cigarette lighter. 
       FIG. 6  shows an alternative embodiment of a wheelchair lift  60 . In this embodiment, hitch  62  may be secured to elevator  64 . At the upper end of elevator  64  is control box  80  that may house various components of the elevator  64 , may provide a mount for a license plate or other indicia and may incorporate other items. At the lower end of elevator  64  is base  72 . Platform  66  is pivotally attached to the base  72  at pivot hinge  74 . Platform  66  in  FIG. 6  is in the horizontal position. Pivot hinge  74  allows platform  66  to transition to a vertical position substantially flush with elevator  64  and perpendicular to the ground. 
     At the distal end  68  of platform  66  is a sensor  70 . In this embodiment, the sensor  70  comprises a video camera that may also be capable of determining distance. At the proximal end  78  of base  72  may be located sensor  76 . Like sensor  70 , sensor  76  comprises a video camera that may also be capable of determining. Switch  82  proximal to base  78  and platform  66  detects whether the platform is in the horizontal or vertical position and activate and deactivate sensors  70  and  76  accordingly. Switch  82  is an wireless electronic communication with both since or  70  and since or  76 . 
     Sensors  70  and  76  and/or switch  82  may be an wireless communication with information module  90 . Information module  90  includes a visual display  84  that may display a video signal from the camera allowing the operator of an automobile to “see” what the sensor  70  or  76  sees. Optionally, video display  84  may display an alphanumeric indicator of the distance from the sensor to a solid object. Information module  90  may also include an audio output  86  that may be used to signal the presence of a solid object in close proximity to the sensors  70  or  76 . Information module  90  may also include a control panel  88 , which may allow the operator to select between various forms of audio and visual signals. Because the components are wireless, there is no need for wiring that may become tangled or damaged. 
     Whereas, the present invention has been described in relation to the drawings attached hereto, it should be understood that other and further modifications, apart from those shown or suggested herein, may be made within the spirit and scope of this invention. Descriptions of the embodiments shown in the drawings should not be construed as limiting or defining the ordinary and plain meanings of the terms of the claims unless such is explicitly indicated. 
     As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.