Abstract:
An appliance lid lock includes a sensing circuit which senses the position of the lid lock relative to the appliance lid. When the appliance lid is in its closed position and the lid lock retentively engages the appliance lid, a controller causes activation of the appliance driver. When the appliance lid is not in its closed position and the lid lock moves beyond its locked position to a third position, a sensing circuit causes the controller to maintain all the appliance drivers in a deactivated state and to return the lid lock to its original unlocked position.

Description:
BACKGROUND OF THE INVENTION 
   The present invention relates to an appliance lid lock and method for using same. 
   Many appliances include an access opening and a lid moveable from an open position to a closed position in covering relation over the access opening. 
   Lid locks have been provided for retentively engaging the lid in its closed position so as to lock it against being opened during the time that the appliance is operating. It is desirable from a safety standpoint to prevent the actuation of the appliance drive system at all times except when the lid is in its closed or locked position. 
   Therefore a primary object of the present invention is the provision of an improved appliance lid lock and method for using same. 
   A further object of the present invention is the provision of an appliance lid lock that prevents actuation of the appliance drive except when the appliance lid is closed and in its locked position. 
   A further object of the present invention is the provision of an appliance lid lock and method for using same which prevents the actuation of the drive mechanism whenever the lid is in an open position or in any position other than its closed and locked position. 
   A further object of the present invention is the provision of an appliance lid lock and method for using same which senses the position of the lid so as to permit the actuation of the appliance drive mechanism only when the lid is in its closed and locked position. 
   A further object of the present invention is the provision of an appliance lid lock and method for using same which is economical to manufacture, durable in use and efficient in operation. 
   BRIEF SUMMARY OF THE INVENTION 
   The foregoing objects may be achieved with a lid lock for an appliance comprising an appliance driver adapted to be activated when electrical power is introduced to the appliance driver and adapted to be deactivated when electrical power is shut off from the appliance driver. A lock member is moveably mounted for sequential movement from an unlock position to a lock position to a third position. An electrical sensing circuit is associated with the lock member for creating first, second and third electrical signals corresponding to sensing when the lock member is in the unlock, lock or third positions respectively. A controller is connected to the sensing circuit for receiving the first, second and third electrical signals. The controller is connected to the appliance driver for causing the appliance driver to become deactivated whenever the lock member is in the unlock and third positions and for causing the appliance driver to be activated whenever the lock member is in the lock position beyond a predetermined interval of time. 
   According to a further feature of the present invention the lock driver is connected to the lock member for moving the lock member between the unlock, lock and third positions and the controller is connected to the lock driver for causing the lock driver to move the lock member to the unlock, lock and third positions and for returning the lock member to the unlock position whenever the lock member is in its third position. 
   A further feature of the invention comprises an appliance cabinet having a lid opening therein and a lid mounted to the cabinet for movement from an open position to a closed position. The lock member engages and locks the lid when the lid is in its closed position and when the lock member is in its lock position. 
   According to another feature of the invention the lock member has a limit surface thereon engaging the lid when the lid is in its closed position and when the lock member is in its lock position so as to prevent the lock member from moving from the lock position to its third position. 
   According to a further feature of the invention the electrical sensing circuit comprises a moveable contact moveable in response to the sequential movement of the lock member from the unlock to the lock and to the third positions, and a fixed contact which engages the moveable contact only when the lock member is in its lock position. 
   According to another feature of the invention the controller keeps the appliance driver in a deactivated state when the moveable contact moves into an electrical contract with the fixed contact for a time interval less than the predetermined time interval. 
   According to another feature of the present invention the lid lock member is pivotably moveable from its unlock position to its lock position to its third position. 
   According to another feature of the present invention the lock driver comprises a solenoid. 
   The method of the present invention comprises sensing when the locking member is in the unlock position, the lock position, and the third position. The method further comprises returning the lid locking member to the unlock position whenever the locking member is sensed to be in the third position. 
   According to another feature of the method of the present invention the appliance includes an appliance driver adapted to be in an activated state or in a deactivated state. The method further comprises maintaining the appliance driver in the activated state only when the lid lock is in the lock position and maintaining the appliance driver in a deactivated state at all other times. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a pictorial view of an appliance cabinet top showing the lid in its open position. 
       FIG. 2  is a view similar to  FIG. 1  but showing the lid in the closed position. 
       FIG. 3  is a sectional view taken along line  3 — 3  of  FIG. 2 . 
       FIG. 4  is a sectional view similar to  FIG. 3  showing along a vertical centerline  114  the three different positions for the lock member of the present invention. 
       FIG. 5  is a top plan view of the lid lock assembly of the present invention. 
       FIG. 6  is an exploded perspective view of the mechanism within the lid lock assembly. 
       FIG. 7  is a perspective view of the mechanism in the lid lock assembly. 
       FIGS. 8 ,  9 , and  10  are views showing the three positions showing the moveable contact relative to the fixed contact of the present invention. 
       FIG. 11  is a schematic view of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring to  FIG. 1  the numeral  10  generally designates an appliance of the present invention. Only the top cover  12  of the appliance  10  is shown but the appliance can include other cabinet portions, depending upon the particular type of appliance involved. 
   Top cover  12  includes control panel (not shown) at its back edge and an access opening  16  for providing access into the interior of the appliance. A lid recess  18  extends around the access opening  16 . A lid  20  is hinged at its rear edge to top cover  12  and folds from its open position shown in  FIG. 1  to its closed position fitting within the recess  18  as shown in  FIG. 2 . 
   Protruding upwardly within recess  18  are a pair of spaced apart lid pads  22 , and protruding horizontally inwardly from the edge of lid recess  18  are a pair of lid locking members shown partially at  24  in  FIG. 1 . Lid locking members  24  are adapted to protrude into a lid lock hole  26  when the lid is in its closed position. As can be seen in  FIG. 3  the lid locking member  24  protrudes through a top cover lock hole  27 . 
   On the under surface of the top cover  12  is a lid lock assembly  28 , and the lid pad  22  protrudes through a pad opening  30  in the top cover  12 . A screw  34  attaches a lock housing  32  to the lid pad  22 , and attaches the lid lock assembly  28  to the top cover  12 . 
   The lid lock assembly  28  includes multiple electrical connectors  36  for connecting the various components to outside components as will be described more fully hereafter in the discussion of the electrical schematic of  FIG. 11 . 
   Referring to  FIGS. 5 ,  6 , and  7 , the interior of the lid lock assembly  28  includes a lock member shaft  38  having the lid locking member  24  at one end thereof. Lid locking member  24  includes a shank portion  40  and a hook portion  42 . At the tip of the hook portion  42  is a pawl  44 , and adjacent the pawl  44  is a shoulder  46 . At the opposite ends of the shaft  38  are a pair of spaced apart links  48  which are rigidly attached to the shaft  38  and which include notches  50  at their lower ends. 
   Notches  50  extend downwardly and retentively engage a pair of studs  56  which are on a sliding carriage  52 . Sliding carriage  52  includes slide flanges  54 . Protruding rearwardly from the slide carriage  52  is a slide guide  58 . 
   A U-shaped moveable electrical contact  60  includes a pair of spaced apart control arms  62  having control contact tips  64  at their ends. Extending between the contact arms  62  is a contact web  66  which fits around and beneath a carriage superstructure  68  on the sliding carriage  52  so that the u-shaped contact  60  is attached to the sliding carriage  52 . Superstructure  68  also includes a rod receptacle  70  which is adapted to receive a rod head  72  at the end of a rod shaft  74 . Two opposite acting solenoids  94 ,  96 , drive rod head  72  in a back and forth reciprocating movement. 
   Fixed to the bottom of the lid lock housing  32  is a carriage track  76  having a guide receptacle  78  for receiving slide guide  58  therein for sliding movement back and forth. Carriage track  76  also includes a pair of spaced apart side rails  80  about which the slide flanges  54  of sliding carriage  52  fit so that the carriage  52  is free to slide in reciprocating opposite directions on the side rails  80 . Side rails  80  are joined by a cross member  82 . Attached between the side rails  80  is a spring  84  which is bowed as shown in  FIG. 6  so that it will flop from the position shown in bold lines in  FIG. 6  to the position shown in shadow lines in  FIG. 6 . A unshaped spring holder  98  is provided on the carriage  52  for retentively fitting over the spring  84 . Thus as the carriage  52  reciprocates back and forth it causes the spring  84  to move between the two positions shown in solid lines and shadow lines in  FIG. 6 . 
   A pair of fixed contacts  86  are mounted on the housing  32  of the lid lock assembly  28 . Shaft  38  is rotatably received within three shaft cradles  88 ,  90 ,  92  so that the lock member  24  can pivot about the axis provided by the shaft  38 . 
   In operation, the solenoids  94  and  96  are actuated one at a time to extend and retract the rod shaft  74 . When the rod shaft  74  is extended it moves the carriage  52  to its outer most position indicated by the arrow  116 . This causes the lid locking member to rotate in a clockwise direction as indicated by the arrow  118  in  FIG. 7 . The solenoid  94  is only activated for a short time to move the carriage  52  to its outermost position. After solenoid  94  is deactivated, the bowed spring  84  yieldably urges the carriage  52  toward its outermost position. 
   Activation of the other solenoid  96  causes retraction of the shaft  74  and causes the slide  52  to move in the direction indicated by the arrow  120  in  FIG. 7 . Correspondingly the lid locking member  24  rotates in a counterclockwise direction as indicated by arrow  122 , and bowed spring  84  assumes the position in shadow lines in  FIG. 6 , so as to urge carriage  52  in the opposite direction. 
     FIGS. 8 ,  9 , and  10  illustrate the three positions of the moveable contacts  64  relative to the fixed contacts  86 . In the initial position with the shaft  74  in its extended position, the moveable contact tips  64  are out of engagement with the fixed contacts  86 . This represents an unlock position. In this position, the lid locking member  24  is in its unlock position shown in the upper portion of  FIG. 4 . 
     FIG. 9  illustrates the moveable contact tips  64  in electrical contact with the fixed contact  86 . This position is the lock position corresponding to the middle portion of  FIG. 4 . In this lock position the shoulders  46  engage the lid  20  to prevent the lid locking member  24  from moving to its third position shown in  FIG. 10 . Spring  84  urges the carriage  52  to its fully retracted position indicated by arrow  120  ( FIG. 7 ), but is prevented from doing so because shoulders  46  of locking member  24  engage the lid  20 . 
   If lid  20  is open or ajar as shown in the bottom of  FIG. 4 , the spring  84  causes locking member  24  to move to the position shown in the bottom of  FIG. 4 . In this position the movable contact tips  64  move out of contact with the fixed contacts  86  ( FIG. 10 ) and this third position is shown at the bottom of  FIG. 4 . 
   Spring  84  plays an important function in the movement of the lid locking member  24  from its unlock position shown at the top of  FIG. 4  to its lock position shown in the middle of  FIG. 4  to its third position shown at the bottom of  FIG. 4 . The spring flips back and forth between the positions shown in solid lines in  FIG. 6  and in the shadow lines of  FIG. 6 . When the spring is in the position shown in solid lines of  FIG. 6  the lid lock  24  is in its unlock position shown at the top of  FIG. 4 . When the spring is in the position shown in shadow lines in  FIG. 6  the lid locking member  24  is in the third position shown in the bottom of  FIG. 4 . Only if the lid  20  is in its closed position does the locking member  24  protrude within the lid lock hole  26  and the shoulder  46  engages the lid  20  to prevent the lid locking member  24  from moving from the lock position, shown in the center of  FIG. 4 , to the third position shown in the bottom of  FIG. 4 . 
   Referring now to the schematic shown in  FIG. 11 , a controller  100  includes a lid lock/unlock sensor  102  therein. Also within controller  100  is a power supply  104 , a lid lock output  106 , a lid unlock output  108 , and an appliance driver output  110 . The appliance output  110  is connected to an appliance driver  112 . 
   In operation, the sensor  102  is connected to fixed contacts  86  at both of the two spaced apart lid lock assemblies  28 . The lid lock sensor is adapted to sense when the moveable contacts  64  are in contact with the fixed contact  86 , and are also adapted to sense when the moveable contacts  64  move past the fixed contacts  86  to the third position shown at the bottom of  FIG. 4  and in  FIG. 10   
   The controller  100  is adapted to actuate solenoid  96  to move the moveable contact  64  from its unlock position towards its lock position. If the lid  20  is in its closed position, the lock member  24  will move to the position shown in the middle of  FIG. 4  and because of the engagement of shoulders  46  with the lid  20  will move no further. Sensor  102  senses when the lid locking member  24  is in this position beyond a predetermined interval of time, and causes the driver output to actuate to the appliance driver. 
   If the lid is open or slightly ajar as shown in the bottom  FIG. 4 , the spring  84  will cause the lid locking member  24  to move to the position in  FIG. 10 . As can be seen in  FIG. 4 , the lid locking member  24  has moved beyond its locked position shown in the middle of  FIG. 4  to its third position shown at the bottom of  FIG. 4 . The lid lock unlock sensor  102  of the controller  100  senses that the moveable contacts  64  have only contacted the contacts  86  for a short time, and consequently does not actuate the driver output  110  or the appliance driver  112 . Instead the controller  100  causes the lid unlock output  108  to be actuated to move the lid locking member  24  back to its initial unlock position shown at the top of  FIG. 4 . In the process of returning the lid locking member  24  to the initial unlock position, the lid lock unlock sensor  102  of the controller  100  again senses instantaneous contact between moveable contacts  64  and contacts  86 . It is in this manner that controller  100  determines that the locking member was indeed in the third position. 
   If the lid lock hole  26  is only slightly misaligned from the locking member  24 , the pawl  44  may contact the lid  20  at a point where the moveable contacts  64  make contact with the contact  86  for a short time, and subsequently the spring  84  urges the locking member  24  back to its initial unlock position as shown in the top of  FIG. 4 . The lid lock unlock sensor  102  will sense the instantaneous contact and the controller  100  will assume the contacts to be in the third position. The controller  100  causes the lid unlock output  108  to be actuated to move the lid locking member  24  back to its initial unlock position shown at the top of  FIG. 4 . Because the lid locking member  24  is already in the initial unlock position, the lid lock unlock sensor  102  will not sense any instantaneous contact between contact  86  and moveable contact  64 . In this case, the controller  100  senses that the contacts  64  were never in the third position. The controller  100  can also turn on an indicator light on the control panel (not shown) indicating to the operator that the lid is in a misaligned position. 
   It is anticipated that another fixed contact could be utilized to provide definitive feedback to the controller  100  when the lock member  24  is in the third position. However, an assumption that the lock member  24  is in the third position whenever instantaneous contact is sensed, will most often be correct. The ability to verify the assumption via the lid lock unlock sensor  102  eliminates the extra expense of this contact, associated wiring, and the additional input to controller  100 . 
   Thus when the lid  20  is in its closed position, the lid locking member  24  moves into locking retentive engagement with the lid  20  and the controller senses this position and actuates the appliance driver. When the lid  20  is ajar or is open, the lid locking member  24  moves over center to the third position shown at the bottom of  FIG. 4 , and the controller senses this and prevents any further actuation of the appliance driver. The controller can also turn on an indicator light on the control panel (not shown) indicating to the operator that the lid is in an unlocked position. 
   When the appliance driver completes its operational cycle the controller causes the lid unlock output  108  to actuate solenoid  94 , to move the moveable contact back to its unlock position. 
   The purpose of the invention, i.e. the third position of the contact tips  64 , is to eliminate the need for a separate switch to indicate the position of the lid. While it is common in the industry to utilize a separate lid switch, the value of this invention is the elimination of the lid switch, associated wiring, assembly labor and the inherent reduction of system reliability induced by another component. The provision of the third position of the contact tips  64  provides the function of a separate lid switch without added cost. 
   In the drawings and specification there has been set forth a preferred embodiment of the invention, and although specific terms are employed, these are used in a generic and descriptive sense only and not for purposes of limitation. Changes in the form and the proportion of parts as well as in the substitution of equivalents are contemplated as circumstances may suggest or render expedient without departing from the spirit or scope of the invention as further defines in the following claims.