Abstract:
An actuator moves the hinged lid of a cooking grill or similar container between a closed position and an opened position when an electronic sensor detects the approach of a person. For example, the actuator can open the lid when a person approaches, and then close the lid at a later time, such as when the person activates a switch or leaves the area, or after a time interval.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application is a continuation-in-part of U.S. patent application Ser. No. 11/126,586, filed on May 11, 2005, which claims the benefit of priority of U.S. Provisional Patent Application Ser. No. 60/627,921, filed Nov. 15, 2004, entitled “AUTOMATED OPENING/CLOSING APPARATUS AND METHOD FOR A CONTAINER HAVING A HINGED LID.” The specifications of these two patent applications are incorporated herein by reference in their entireties for all purposes. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates generally to the field of automated opening and closing mechanisms and, more particularly, to an automated opening/closing system for a cooking grill or similar container having a hinged lid. 
         [0004]    2. Description of the Related Art 
         [0005]    An outdoor cooking grill, also commonly referred to as a “barbecue grill,” “barbecue,” or simply “grill,” may include a hinged lid that covers the cooking surface. A hinged lid is a particularly common feature of grills fueled by propane and natural gas, though other grills may have lids as well. Many persons who enjoy cooking on a grill find it awkward to open the grill lid while carrying a plate of food and cooking utensils. Thus, it can be seen that needs exist for a hands-free way of opening and closing a grill with a hinged lid. It is to such an apparatus and method that the present invention is directed. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention relates to an apparatus and method for automatically moving a hinged lid of a cooking grill or similar container between an opened and closed position, i.e., from a closed position to an opened position in some embodiments of the invention, from an open position to a closed position in other embodiments, or in both directions in still other embodiments. The apparatus includes an actuator system and a controller system. 
         [0007]    The actuator system is mountable to the grill and has a means for transmitting motion to the lid, such as an arm, a system of cables and pulleys, sprockets and chains, a linear actuator, a threaded rod and ball nut, etc., or combinations thereof. The controller system has an electronic sensor, which may be of a photoelectric, optical, ultrasonic, infrared, microwave, inductive, or other suitable type, which senses the approach of a user (or object the user is carrying) to the grill or detects an event that occurs external to the grill and, in response, triggers the actuator system to move the lid from one position to the other, most preferably from the closed position to the open position. In some embodiments of the invention, a user-operated control, such as a foot pedal or a switch, can further be included to trigger the actuator system to move the lid in the other direction, such as from the open position back to the closed position, or alternatively, in other embodiments, as a manual override to trigger the actuator system to move the lid in the same direction as if triggered by the sensor. In still other embodiments, the controller system can close the lid in response to other conditions, such as when the sensor senses the user has left the area or after a predetermined amount of time has elapsed since the grill lid opened. 
         [0008]    Advantageously, the present invention thus provides a “hands-free” way of operating hinged lid of a cooking grill. A user simply walks close to the grill, and the lid opens. In other words, the user exerts no force to cause the lid to open. To close the grill, the user can simply activate a foot pedal, which may be located several feet away from the hot grill, thereby preventing the user from inadvertently burning himself. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0009]      FIG. 1  is perspective view of a grill with an attached apparatus for opening and closing the grill lid in accordance with one embodiment of the present invention. 
           [0010]      FIG. 2  is a side elevational view of the grill and attached apparatus of  FIG. 1 . 
           [0011]      FIG. 3  is side elevational view similar to  FIG. 2  but from the opposite side of the grill and showing the lid in an opened position. 
           [0012]      FIG. 4  is perspective view of a grill with an attached apparatus for opening and closing the grill lid in accordance with another embodiment of the present invention. 
           [0013]      FIG. 5  is a side elevational view of the grill and attached apparatus of  FIG. 4 . 
           [0014]      FIG. 6  is side elevational view similar to  FIG. 5  but from the opposite side of the grill and showing the lid in an opened position. 
           [0015]      FIG. 7  is schematic diagram of a circuit for controlling the opening and closing of the lid. 
           [0016]      FIG. 8  is a side elevational view of a grill with an attached apparatus for opening and closing the grill lid in accordance with another embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION  
       [0017]    In the following description, like reference numerals indicate like components to enhance the understanding of the invention through the description of the drawings. Also, although specific features, configurations, arrangements and steps are discussed below, it should be understood that such specificity is for illustrative purposes only. A person skilled in the relevant art will recognize that other features, configurations, arrangements and steps are useful without departing from the spirit and scope of the invention. 
         [0018]    As illustrated in  FIG. 1 , an actuator system  10  is mounted to a grill  12  and electrically connected to a controller system  14  ( FIG. 7 , described below) that includes an electronic sensor  16 , such as a photoelectric eye. Grill  12  has a hinged lid  18 , shown in a closed position in  FIG. 1 . As described in further detail below, controller system  14  causes actuator system  10  to move lid  18  to an open position, as shown in  FIG. 3 , when electronic sensor  16  detects a person near grill  12 . Actuator system  10  can be mounted at any suitable place on the grill (such as below a shelf of the grill). 
         [0019]    Actuator system  10  includes a suitable motor  20  (best shown in  FIG. 3 ), such as a reversible  12  VDC gearmotor, with a shaft coupled to two drive pulleys  22  and  24 . Motor  20  and associated pulleys  22  and  24  are mounted to a bracket  26 , which in turn is bolted to the rear of grill  12 . Because the rear of grill  12  can be expected to become hot during use, the fastening hardware used to attach bracket  26  to grill  12  can include one or more suitable insulating materials such as ceramic spacer  27 . Such ceramic spacers can withstand temperatures up to about 2100 degrees Fahrenheit. Other suitable insulating or heat-resistant materials can be used, including TEFLON® spacers, which typically withstand temperatures up to about 500 degrees Fahrenheit. Additionally, the insulating materials can be about the same size of the contact area of the bracket  26 . In a typical commercial embodiment, the one or more spacers  27  are approximately ¼ inch to ⅜ inch thick, although those skilled in the art will understand that the dimensions of the spacers can vary. 
         [0020]    A second bracket  28  can also be included to stabilize bracket  26 . Some or all of the above-described elements, such as motor  20  and associated pulleys  22  and  24  can be enclosed in a safety enclosure or shroud (not shown for purposes of clarity). The enclosure, bracket  26 , and other such elements can be made of aluminum, stainless steel or other suitable material for corrosion resistance. 
         [0021]    One end of a first cable  30  is taken up by pulley  24 , and the other end is routed via two idler pulleys  32  and  34  to an end of an elongated stainless steel bracket  36  attached to an upper portion of the rear of lid  18 . One end of a second cable  38  is taken up by pulley  22  and routed via three idler pulleys  40 ,  42  and  44  to a clevis  46  (best shown in  FIG. 3 ) attached to a lower portion of the front of lid  18 . Cables  30  and  38  can comprise, for example, 1/16-inch diameter stainless steel wire rope, and the other elements can similarly be made of stainless steel for corrosion resistance, with suitable insulating spacers included in the attaching hardware. Note that in other embodiments of the invention, the elements of actuator system  10 , including the motor, cables and any associated drive pulleys, idler pulleys, etc., can be arranged and mounted in any other suitable manner. 
         [0022]    Electronic sensor  16  is mounted to grill  12  in a location suitable for detecting the approach of a person or other signal. For example, in the illustrated embodiment of the invention it is mounted beneath the shelf  48  with a small bracket (not shown for purposes of clarity). Electronic sensor  16  can be a photoelectric eye of the type known in the art as “diffuse,” which acts as a photoswitch in response to changes in light reaching it caused by a person in close proximity (e.g., approximately 24-36 inches). Electronic sensor  16  is positioned high enough to avoid activation by a family pet or small child. Although in the illustrated embodiment of the invention electronic sensor  16  is of photoelectric technology, in other embodiments it can be of any other suitable technology and can be mounted in any other suitable location. For example, a pressure mat switch can be activated when a user steps on it in front of the grill. 
         [0023]    Controller system  14  further includes two DPDT wobblestick-type limit switches  50  and  52 . When lid  18  is in the fully closed position (see  FIGS. 1-2 ), limit switch  52  is engaged by contact with lid  18 . When lid  18  is in the fully opened position (see  FIG. 3 ) limit switch  50  is engaged by contact with lid  18 . In positions between these two positions, both switches  50  and  52  are disengaged. 
         [0024]    As illustrated in  FIG. 7 , controller system  14  includes, in addition to above-described electronic sensor  16  and switches  50  and  52 : a 4-pole relay  54 , a single-pole relay  56 , and two latching relays  58  and  60 . A 12 VDC battery  62  and a supplemental DC power supply  64  of the type that can be plugged into a standard electrical wall outlet (not shown) provide power to controller system  14  and motor  20 . A fuse  65  can also be included for protection. Controller system  14  can further include a manually operated override switch  66  that can be used to turn the entire system off so that lid  18  does not automatically open. In addition, controller system  14  can include a foot pedal switch  68  for causing lid  18  to close. Foot pedal switch  68  can be pneumatically activated, with a flexible air tube  90  connecting a pneumatic pedal  92  on the ground to the electrical contact portion of the switch, which can be located with relays  54 - 60  and any other electronic components in a suitable enclosure (not shown) mounted in a suitable location on grill  12 . Flexible air tube  90  can comprise ¼ inch tubing, although those skilled in the art will understand that other suitable tubing can be employed, whether flexible or not. Preferably, the tubing is at least several feet long so that the foot pedal can be placed somewhat away from the hot components of the grill. Such placement allows the user to activate the foot pedal without risking burning himself. In a typical commercial embodiment, the flexible tubing is approximately 6 feet long, although in other embodiments, this length can vary. Preferably, a pneumatic foot pedal  92  or switch is used (and not a mechanical foot pedal) because the pneumatic pedal is generally safer (as there is no electric parts/ electricity that could come into contact with a wet ground) and less likely to break (as there is no risk of broken springs, linkage pivot point failures due to corrosion, or other mechanical failure). 
         [0025]    In operation, when a user approaches grill  12 , electronic sensor  16  activates the above-described relay circuitry. In response, the circuitry powers motor  20  in a direction that reels in some of cable  30  and correspondingly reels out some of cable  38 . Cable  30  pulls on bracket  36 , causing lid  18  to open. When lid  18  reaches the fully opened position, it engages limit switch  50 , which causes the circuitry to cease powering motor  20 . Preferably, lid  18  takes no more than about three seconds to reach the fully opened position after sensor  16  is activated. Motor  20  remains in the fully opened position until the user depresses foot pedal switch  68 . In response, the circuitry powers motor  20  in the opposite direction, thereby reeling in some of cable  38  and correspondingly reeling out some of cable  30 . The action of cables  30  and  38  causes lid  18  to close. When lid  18  reaches the fully closed position, it engages limit switch  52 , which causes the circuitry to cease powering motor  20 . Although in the illustrated embodiment of the invention a foot pedal switch is used to cause lid  18  to close, in other embodiments the lid can be closed in any other suitable way, such as in response to a timer circuit. For example, the sensor can detect when the user is no longer near the grill, and the circuitry can cause the lid to close a minute or two thereafter. Additionally, the user can manually open lid  18  (e.g., if electrical power is lost) and manually close lid  18 . 
         [0026]    An alternative embodiment of the invention is illustrated in  FIGS. 4-6 . As in the embodiment described above with regard to  FIGS. 1-3 , an actuator system  70  is mounted to a grill  72  and electrically connected to a controller system, which is not shown in  FIGS. 4-6  for purposes of clarity but which can be the same as controller system  14  ( FIG. 7 ) described above with regard to the other embodiment, including a photoelectric eye or other electronic sensor mounted in a suitable position on grill  72 . Actuator system  70  includes a suitable motor  74  (best shown in  FIG. 6 ) coupled to a drive pulley  76 . Motor  74  and pulley  76  are mounted to a bracket  78 , which in turn is bolted to the rear of grill  72  in the same manner as in the above-described embodiment. These elements can be enclosed in a heat-resistant safety enclosure or shroud (indicated in dashed line). 
         [0027]    One end of a cable  80  is taken up by pulley  76 , and the other end is attached to the upper portion of the rear of the lid  82 . A closing arm  84  pivots on bracket  78  and has a heat-resistant roller  86  at its distal end and a tension spring  88  extending between its proximal end and bracket  78 . 
         [0028]    In operation, when a user approaches grill  72 , the electronic sensor activates the relay circuitry of controller system  14  in the same manner as in the above-described embodiment. In response, the circuitry powers motor  74  in a direction that reels in some of cable  80 , thereby pulling lid  82  open. When lid  82  is in the fully closed position, arm  84  engages a limit switch  52 A, which is of the same type and connected in the circuitry in the same manner as limit switch  52  of the above-described embodiment. When lid  82  reaches the fully opened position (see  FIG. 6 ), it engages a limit switch  50 A, which is of the same type and connected in the circuitry in the same manner as limit switch  50  of the above-described embodiment. This causes the circuitry to cease powering motor  74 . As in the above-described embodiment, motor  74  remains in the fully opened position until the user depresses the foot pedal switch (see  FIG. 7 ). In the fully opened position, spring  88  biases arm  84  against the rear of lid  82 . In response to the user depressing the foot pedal switch, the circuitry powers motor  74  in the opposite direction, thereby allowing some of cable  80  to unreel from pulley  76  as arm  84  pushes lid  82  closed. When lid  82  reaches the fully closed position, it again engages limit switch  52 A, which causes the circuitry to cease powering motor  74 . 
         [0029]    Another alternative embodiment is shown in  FIG. 8 . The apparatus  100  for opening and closing the lid  18  is substantially similar to that described with reference to  FIGS. 1-3 , but with the exceptions noted herein. An actuator system  102  includes an electric or linear actuator  104  electrically coupled to a photoelectric sensor (not shown). One end of the linear actuator is mounted to the grill  12  and the other end is mounted to the lid  18  such that once activated, the motor of the linear actuator causes the lid to open. Such linear actuators are generally well known in the art and thus are not described herein. Optionally, a controller system includes a safety switch  106  that when activated causes the photoelectric sensor to deactivate (or turn off), thereby providing a safety feature. For example, if the grill is not in use, a user can activate the safety switch  106  to keep the lid from opening when a person walks in proximity of the photoelectric sensor. As shown, the fastening hardware used to attach linear actuator  104  to grill  12  and lid  18  can include suitable insulating or heat-resistant materials such as a ceramic or TEFLON® pad  10 . Additional heat-resistant pads  112 ,  114 ,  116 , and  118  can be use to insulate other portions of contact between the opening and closing apparatus  100  and the grill  12 . As discussed herein, such heat-resistant materials can withstand temperatures up to about 2100 degrees Fahrenheit. Preferably, the heat-resistant materials can be about the same size of the contact area of the linear actuator&#39;s mounting bracket. Those skilled in the art that the use of any suitable insulator or heat resistant material is within the scope of the present invention. 
         [0030]    Those skilled in the art will understand that opening/closing systems of the present invention can easily be retrofitted to existing grills (or other similar such containers having a hinged lid). 
         [0031]    It will be apparent to those skilled in the art that various modifications and variations can be made to this invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention covers the modifications and variations of this invention provided that they come within the scope of any claims and their equivalents. With regard to the claims, no claim is intended to invoke the sixth paragraph of 35 U.S.C. Section 112 unless it includes the term “means for” followed by a participle.