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BACKGROUND OF THE INVENTION  
         [0001]    The invention relates to gates and in particular unlocking of gates.  
           [0002]    Gates are useful to inhibit undesired access through the gate while permitting relatively easy access if desired. Child safety gates are useful to help prevent injuries to children by inhibiting access through the gate by a child while permitting easy access through the gate by an adult. These gates can be mounted, e.g., in doorways, in hallways, between a wall and a stairway railing, or between two stairway railings (such as on a deck). With the gate in place, children are inhibited from accessing areas that are undesirable for the child to access. For example, it may be desirable to inhibit a child from accessing a kitchen, where toxic cleaners may be stored, or a stairway that the child may fall down. Safety gates can also inhibit children from gaining access to a pet or vice versa. A door of the gate can permit access if the door is moved to provide a passageway through the gate.  
         SUMMARY OF THE INVENTION  
         [0003]    The invention provides a mechanism to guard against children undesirably opening a gate and also provides hands-free unlocking and opening of a gate. Among other uses the invention is highly effective in providing an obstruction to help prevent children or animals from accessing an area that it is undesirable for the child or animal to access. For example the invention can be used to block a doorway, hallway or other passageway.  
           [0004]    In general, in one aspect, the invention provides an apparatus including a pair of frame members adapted for mounting to opposing surfaces of a passageway. A door is mounted to at least one of the frame members for movement between a closed position, in which the door and frame members substantially traverse the passageway, and an open position, in which a portion of the passageway is free of the door and frame members, the portion being large enough to permit passage of an adult therethrough. A lock is coupled to at least one of the frame members and adapted to retain the door in the closed position, the lock including an actuator adapted to release the lock to permit movement of the door from the closed position toward the open position upon application to the actuator of a force of at least a predetermined weight of a child.  
           [0005]    Implementations of this aspect of the invention may include one or more of the following features. The actuator is disposed near a bottom portion of a frame member when the pair of frame members are mounted to the opposing surfaces. The predetermined weight is approximately 40 pounds. The lock is adapted to couple a frame member to the door near both a top of the door and a bottom of the door.  
           [0006]    The actuator is adapted to move a recess camming surface, defining a portion of a recess, relative to and against a detent camming surface, of a detent that is biased into the recess when the door is in the closed position and the lock is in a locked position, to substantially remove the detent from the recess. The door is pivotally mounted to the frame about a pivot axis and the detent is a pin that is biased radially outward from the pivot axis. A substantially U-shaped frame includes the frame members and a cross member, the frame members being first and second arms forming sides of the U and the cross member connecting the arms and forming a bottom of the U, the door being pivotally attached to the first arm, and the actuator includes a bracket slidably carried by the second arm and including the recess camming surface. The door includes another pin, and the actuator includes a foot pedal, coupled to the bracket and movably mounted to the frame, including a foot pedal camming surface that provides a wall of a foot pedal recess and that moves relative to and against a pin camming surface, of the another pin that is biased radially outward from the pivot axis and into the foot pedal recess when the door is in the closed position and the lock is in the locked position, to substantially remove the another pin from the foot pedal recess when the foot pedal moves relative to the frame. The arms extend away from the cross member and away from each other.  
           [0007]    In general, in another aspect, the invention provides a safety gate for use in a doorway, hall, or the like. The safety gate includes a substantially U-shaped frame having first and second arms connected by a cross member, the frame providing a passageway between the arms above the cross member. A bracket is movably coupled to the second arm and provides a bracket recess, a part of the bracket recess being provided by a bracket camming surface. A foot pedal is coupled to the bracket and movably coupled to the frame near the bottom end of the second arm. A spring is coupled to the foot pedal and requires a predetermined force to change a length of the spring. A door is pivotally mounted to the first arm along a pivot axis and includes a pin biased away from the pivot axis and configured to be received by the bracket recess, the door substantially preventing an infant from passing through the passageway when the pin is received by the bracket recess. When the foot pedal is moved toward a bottom of the frame in a gate-opening direction, the bracket camming surface bears against the pin to move the pin substantially out of the bracket recess.  
           [0008]    Implementations of this aspect of the invention may include one or more of the following features. The predetermined force is about a weight of a three-year-old child. The passageway extends from a first side of the frame to a second side of the frame, and a portion of the foot pedal is disposed on the first side of the frame and another portion of the foot pedal is disposed on the second side of the frame. The first and second arms are adapted to engage opposing surfaces and extend from the cross member and away from each other such that when the arms are coupled to the surfaces such that the arms extend substantially perpendicular to the cross member, a force of less than about 40 pounds applied to the gate is insufficient to slide either arm relative to a respective one of the surfaces.  
           [0009]    The bracket and the foot pedal are slidably carried by the second arm. The pin is a first pin, the foot pedal provides a foot pedal recess, partially provided by a foot pedal camming surface, the door includes a second pin biased away from the pivot axis and configured to be received by the foot pedal recess, and when the foot pedal slides relative to the frame in the gate-opening direction, the foot pedal camming surface bears against the second pin to move the second pin substantially out of the foot pedal recess.  
           [0010]    In general, in another aspect, the invention provides an apparatus for use with a door movably mounted to a frame member between an open position and a closed position. The apparatus is adapted to inhibit the door from moving from the closed position toward the open position while in a locked position and to change to an unlocked position to permit the door to move from the closed position toward an open position if a force of at least a predetermined weight of a child is applied to the apparatus.  
           [0011]    Implementations of this aspect of the invention may include one or more of the following features.  
           [0012]    The door includes a door member having a door member camming surface and the apparatus includes an apparatus camming surface. The apparatus is further adapted to move the apparatus camming surface relative to the door when the force is applied to the apparatus and to remain substantially fixed relative to the door otherwise. The apparatus camming surface is configured and disposed to cause one of the camming surfaces, biased into a recess provided at least partially by the other camming surface, to be substantially removed from the recess. A portion of the apparatus is adapted to be slidably carried by the frame. The apparatus includes a bracket, slidably coupled to the frame, and an actuator to which the force is applied, the bracket including the apparatus camming surface. The recess is a first recess, the member is a first member, and the member camming surface is a first member camming surface, and the actuator includes an actuator camming surface configured and disposed to cause one of the actuator camming surface and a second member camming surface of a second member of the door, biased into a second recess provided at least partially by the other one of the actuator camming surface and the second member camming surface, to be substantially removed from the second recess when the force is applied to the apparatus. The apparatus comprises a foot pedal to which the force is applied.  
           [0013]    Various aspects of the invention may provide one or more of the following advantages. A gate can be unlocked in a hands-free manner. A gate can also be unlocked and opened in a hands-free manner. Accidental opening of a gate can be guarded against. Undesired opening of a gate by a child or an animal such as a pet can also be guarded against.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]    [0014]FIG. 1 is a perspective view of an assembled safety gate, in a closed position, according to the invention.  
         [0015]    [0015]FIG. 2 is an exploded perspective view of some of the components of the safety gate shown in FIG. 1.  
         [0016]    [0016]FIG. 3 is a cross-sectional view of the safety gate shown in FIG. 1 taken along line  3 — 3  shown in FIG. 1.  
         [0017]    [0017]FIG. 4 is a top perspective view of a foot pedal support shown in FIG. 2.  
         [0018]    [0018]FIG. 5 is a bottom perspective view of a foot pedal shown in FIGS. 1 and 2.  
         [0019]    [0019]FIG. 6 is a perspective view of a bracket shown in FIGS. 1 and 2.  
         [0020]    [0020]FIG. 7 is an enlarged portion of the cross-sectional view of the safety gate shown in FIG. 3 as indicated by line  7 — 7 , with the bracket shown in FIG. 6 in a locked position.  
         [0021]    [0021]FIG. 8 is view similar to that shown in FIG. 7 but with the bracket shown in FIG. 6 in an unlocked position.  
         [0022]    [0022]FIG. 9 is a perspective view of a wrench for use with the gate shown in FIG. 1.  
     
    
     DESCRIPTION OF PREFERRED EMBODIMENTS  
       [0023]    As shown in FIG. 1, a gate  10  includes a frame  12 , a door  14 , a foot pedal  16 , and a bracket  18 . The gate  10  is adapted to be mounted between opposing surfaces  11 ,  13 ,  15 , and  17 , e.g., opposing sides of a doorway, walls of a hallway, or railings of a stairwell. With door  14  in a closed position  19  (as shown), frame  12  and door  14  are sized to substantially block the passageway in which gate  10  is disposed. When disposed in the passageway, gate  10  provides spaces between bars of the frame  12  and door  14 , and between frame  12  and the surfaces between which gate  10  is disposed, that are too small for children to fit through. Door  14  is pivotally mounted to frame  12  by an upper hinge  20  and a lower hinge  70  along a pivot axis  74 . Thus, door  14  can be pivoted from closed position  19 , shown in solid lines, to open positions such as open positions  22  and  24  indicated in simplified form with dashed lines. Positions  22  and  24  are not necessarily fully-open position. Door  14  can be pivoted from the closed position  19  in a direction  26  toward open position  22  and in a direction  28  from open position  22  toward closed position  19 . Similarly, door  14  can be pivoted in a direction  30  from a closed position  19  toward open position  24  and in a direction  32  from open position  24  toward closed position  19 . Foot pedal  16  and bracket  18  provide a locking and unlocking mechanism as described below.  
         [0024]    As shown in FIG. 2 (that shows some but not all components of gate  10 ), gate  10  includes components in addition to frame  12 , door  14 , foot pedal  16 , and bracket  18 . Gate  10  also includes a linkage  34 , a bias spring  36 , a mounting assembly  38 , a pad  40 , a foot pedal support  42 , and a frame support  44 . Door  14  includes a barrier  46 , an upper assembly  48  and a lower assembly  50 .  
         [0025]    Frame  12  is substantially U-shaped with two hollow D-shaped arms  52  and  54  connected at their respective bottoms by a cross member  56 . Arms  52  and  54  are also connected to cross member  56  through two extensions  58  and  60  and two bars  62  and  64 , respectively. Arms  52  and  54  and bars  62  and  64  extend away from cross member  56 , and slightly outward, away from each other, in directions  57  and  59 . Angles  61  and  63  between arms  52  and  54  and cross member  56  are slightly greater than 90°. Arms  52  and  54  are angled outwardly to provide a spring force such that a predetermined force is needed to move arms  52  and  54  inward to extend perpendicularly from cross member  56 . The predetermined force is selected to secure gate  10  between surfaces  11  and  13  and to inhibit children from overcoming the friction produced between gate  10  and surfaces  11  and  13 . Bars  62  and  64  are shaped and disposed to provide gate  10  with an appropriate width for substantially filling a passageway having a width between about 29 inches and about 34 inches. For example, bars  62  and  64  can provide a width of about 29 inches for frame  12 . The top of arm  52  is adapted to receive hinge  20  (FIG. 1) for pivotal connection to door  14  at an upper pivot point  66  of barrier  46 . Cross member  56  provides a hole  68  for receiving hinge  70  (FIG. 1) for pivotal coupling to door  14  at a lower pivot point  72  of barrier  46  such that door  14  can be pivotally coupled to frame  12  along pivot axis  74  (FIG. 1). Arm  54  is shaped to receive spring  36  and linkage  34  in an opening  76  that extends along the length of arm  54 . Upper slots  78  and  79  (only slot  78  shown) in arm  54  are sized to receive a rivet  80  and lower slots  82  and  83  (only slot  82  shown) are sized to receive a rivet  84 . Holes  86  and  88  (only hole  86  is shown) are sized to receive pins  90  and  92 , respectively. Pins  90  and  92  can extend into, but not all the way through, opening  76  of arm  54 .  
         [0026]    Referring to FIGS. 2 and 3, spring  36  and linkage  34  are received in opening  76  of arm  54 , with spring  36  resting on pins  90  and  92  (indicated by dashed lines in FIG. 3). A lower portion  94  of linkage  34  is received by an interior  96  of spring  36 . A ledge  97  of linkage  34  rests on top of spring  36 . Spring  36  is configured such that with linkage  34  resting on top of spring  36  and attached to foot pedal  16  and foot pedal support  34 , a predetermined force is required to be exerted downwardly on linkage  34  as indicated by arrow  100  to compress spring  36 . This predetermined force is preferably greater than a typical weight of a three year old child, e.g., approximately 40 pounds.  
         [0027]    Referring also to FIG. 4, linkage  34  is connected to foot pedal support  42  by rivet  84 . Support  42  provides holes  102  and  104  for receiving rivet  84 . Support  42  is configured to fit over a flat side  106  (FIG. 2) of D-shaped arm  54 , with arm  54  being received by a recess  108  of support  42 .  
         [0028]    As shown in FIGS. 2 and 5, foot pedal  16  is configured to fit over a rounded side  110  of D-shaped arm  54  and to couple to pedal support  42  (FIG. 4). Pedal  16  is adapted to receive support  42  in a recess  112  and to snap on to support  42 . A U-shaped opening  114  in the top of the pedal  16  is shaped to slidably receive curved side  110  of arm  54 . On the outside of a closed end  116  of pedal  16 , a recess  118  is provided by several walls of pedal  16 . One of these walls is an angled wall  120  that provides a camming surface  121 , connected to a flat surface  123 , for engaging and interacting with a camming surface  168  of a pin  122  of lower assembly  50  (FIG. 2).  
         [0029]    As shown in FIGS. 2 and 3, lower assembly  50  includes pin  122 , a cap  124 , and a spring  126 . Pin  122  as shown has a cylindrical shape, but other types of shapes, such as rectangular, are acceptable. Cap  124  is adapted to receive spring  126  and pin  122  and to be received by a hollow end  128  of barrier  46 . When gate  10  is assembled, pin  122  is biased by spring  126  to be received by recess  118  (FIGS. 3 and 5) of pedal  16 . Assembly  50  is similar to assembly  48  which will be described in more detail below.  
         [0030]    Referring also to FIG. 6, a hole  129  in linkage  34  receives rivet  80  that couples linkage  34  through slots  78  and  79  in arm  54  to bracket  18 . Bracket  18  receives rivet  80  in two holes  132  and  134  (only hole  132  shown in FIG. 6). The bracket  18  provides a U-shaped recess  130  adapted to fit over curved side  110  of arm  54 . On the outside of a rounded end  136 , bracket  18  provides a recess  138 . Recess  138  is provided by several walls, including a wall  140  that provides an angled camming surface  141  and is connected to a flat surface  143 . Recess  138  is shaped such that when bracket  18  is received by rounded side  110  of arm  54 , bracket  18  can slide along the length of arm  54 .  
         [0031]    Bracket  18  is guided for sliding along the length of arm  54  by arm  54  and rivets  84  and  80  received by slots  82  and  83 , and  78  and  79 , respectively. Slots  82 ,  83  and  78 ,  79  limit the range of motion of rivets  84  and  80 , and therefore limit the range of motion of linkage  34  relative to arm  54 . This in turn limits the range of motion of pedal  16  and bracket  18  relative to frame  12  and door  14 .  
         [0032]    Referring to FIGS. 2, 6 and  7 , door  14  includes barrier  46  and upper and lower assemblies  48  and  50 .  
         [0033]    Barrier  46  is made of, e.g., plastic and includes two hollow cross members  220  and  222  connected (e.g., sonically welded) to several bars  224 . Bars  224  are separated by distances too small for infants of crawling age or older (e.g., older than 4 months) to fit through.  
         [0034]    Upper assembly  48  includes a pin  142  adapted to be received by recess  138  of bracket  18 , a cap  144  adapted to be received by barrier  46 , and a spring  146 . Like pin  122 , pin  142  as shown has a cylindrical shape, but other types of shapes, such as rectangular, are acceptable. Pin  142  has an end camming surface  148  configured to contact and slide against a wall  150 , camming surface  141  of wall  140 , and a flat surface  143 , of bracket  18 . Cap  144  fits inside an opening  152  (FIG. 2) of barrier  46  and has an end portion  154  that butts up against the end of top cross member  220  of barrier  46 . Pin  142  slidably fits within a hole  158  in cap  144 . A flared region  160  of pin  142  provides a recess  162  for receiving an end of spring  146 . The other end of spring  146  fits over a post  164  of cap  144 . Spring  146  biases pin  142  in a direction away from pivot access  74  (FIG. 1) and away from barrier  46  and toward bracket  18  in a direction transverse to pivot access  74  as indicated by an arrow  166  (see also FIG. 1). With door  14  in closed position  19  (FIG. 1) as shown, spring  146  biases pin  142  into recess  138 .  
         [0035]    Referring to FIGS. 2, 3, and  5 , lower assembly  50  is configured similarly to upper assembly  48 , with spring  126  and pin  122  received by cap  124 , and pin  122  biased toward foot pedal  16  and into recess  118 . Pin  122 , similar to pin  142 , has a surface  168  adapted to be a camming surface to engage, interact with, and slide against a bottom surface  170  and surfaces  121  and  123  of pedal  16 .  
         [0036]    Referring to FIGS. 2 and 7, assembly  38  includes a cap  172 , a nut  174 , a knob  176 , a rod  178 , an end piece  180 , and a pad  182 . Cap  172  fits inside an opening  184  of extension  60  of frame  12  and an end  186  of cap  172  butts up against an end of extension  60 . Cap  172  includes a sleeve  188  with a finger  190  having a tab  192  at its end. An inner diameter  194  of sleeve  188  is sized to accommodate an outer diameter  195  of rod  178 . Tab  192  is disposed to interfere with rod  178  and finger  190  is adapted to flex to allow tab  192  to be moved to a position such that tab  192  will not interfere with rod  178 . Rod  178  has a threaded body  196  extending at least about three inches and over substantially the entire length of rod  178  except for a head  198 . Over head  198  and a portion of body  196  is the end piece  180 . End piece  180  provides a circular recess  200  into which pad  182  can be inserted and attached, e.g., by an adhesive. Pad  182  is made of e.g., a high friction elastomeric such as rubber. Knob  176  provides an opening  202  for receiving body  196  of rod  178 . Knob  176  also provides an opening  204  into which nut  174  can be press fit. Nut  174  provides a threaded inner opening  206  adapted to mesh with threaded body  196  of rod  178 . Knob  176  provides an outer surface  208  adapted to be gripped and turned by a user. Three other assemblies similar to assembly  38  are provided (FIG. 1) for insertion into an open end of extension  58  and open ends of cross member  56  (FIG. 1).  
         [0037]    Referring to FIG. 2, pad  40  is adapted to be mounted to two bars  224  of barrier  46 . Pad  40  is shaped and disposed to be pushed by, e.g., an adult&#39;s knee. Pad  40  can be snapped on to bars  224  at various positions.  
         [0038]    Frame support  44  is adapted to rest on a flat surface such as the floor and to receive cross member  56  of frame  12 . Support  44  provides an opening  210  along its length sized to receive cross member  56  of frame  12 .  
         [0039]    A wrench  300 , as shown in FIG. 9, is provided with gate  10 . Wrench  300  has an open end  302  with an inner opening  304  shaped to receive knob  176  (FIGS. 2 and 7) and to engage outer surface  208  (FIG. 7) of knob  176  so that knob  176  can be turned using wrench  300 . Wrench  300  has a flat handle  306  of a thickness  308 .  
         [0040]    Referring to FIGS. 1-7, pieces of gate  10  can be made as follows. Frame  12  and barrier  46  are welded of steel in the configurations shown. Foot pedal  16 , bracket  18 , foot pedal support  42 , pad  40 , and frame support  44  are injection molded acrylonitrile butadiene styrene (ABS). Holes and slots provided by frame  12  can be machined after frame  12  is injection molded or can be formed as part of the injection molding. Caps  172 , knobs  176 , and end pieces  180  are also molded ABS. Springs  36 ,  126  and  146  are made of steel, as well as rivets  80  and  84 , nut  174 , and rod  178 .  
         [0041]    Gate  10  can be assembled as follows. Linkage  34  is inserted into interior  96  of spring  36 . Linkage  34  and spring  36  are inserted into opening  76  of arm  54  and positioned by inserting pins  90  and  92  into holes  86  and  88  respectively. Foot pedal support  42  is fit onto square side  106  of arm  154  and positioned so that hole  102  and hole  104  align with slot  82  and slot  83 . Rivet  84  is inserted through hole  102  in support  42 , slot  82  in arm  54 , hole  98  in linkage  34 , slot  83  in arm  54 , and hole  104  in support  42 , and flattened in a conventional manner. Foot pedal  16  is fit onto rounded side  110  of arm  54  and snapped onto foot pedal support  42 . Bracket  18  is fit onto rounded side  110  of arm  54  and rivet  80  inserted through hole  132  in bracket  18 , slot  78  in arm  54 , hole  128  in linkage  34 , slot  79  in arm  54 , and hole  134  in bracket  18  and flattened in a conventional manner.  
         [0042]    Referring to FIGS. 2 and 7, assembly  38  is assembled and coupled to extension  60 . End piece  180  is injection molded over head  198  and pad  182  is glued into recess  200  of end piece  180 . Cap  172  is press fit into extension  60 . Nut  174  is pressed fit into opening  204  of knob  176  to form a knob assembly  212  (FIG. 7). Rod  178  is inserted through knob assembly  212  by turning rod  178  to thread nut  174  onto body  196  of rod  178 . Rod  178  is inserted into sleeve  178  of cap  172 . As rod  178  is inserted into sleeve  188 , threads on body  196  will interfere with tab  192 . Finger  190  will flex to allow tab  192  to move out of the way of threads on body  196  to allow rod  178  to be inserted into sleeve  188 . Other assemblies similar to assembly  38  are similarly assembled and coupled to extension  58  and ends of cross member  56  of frame  12 .  
         [0043]    Pad  40  is snapped to a desired location of bars  224  of barrier  46 . Alternatively pad  40  can be permanently fixed by, e.g., sonic welding to barrier  46 . Frame  12  is inserted into frame support  44  such that cross member  56  is received by opening  210 .  
         [0044]    Referring to FIGS. 2, 3, and  7 , upper assembly  48  is assembled and coupled to barrier  46 , which is coupled to frame  12 . Pin  142  is inserted through hole  158  provided in cap  144 . Spring  146  is inserted into cap  144  through an opening  244  (FIG. 2) provided in the top of cap  144 . Spring  146  is placed into recess  162  of flared end  160  of pin  142  and also placed over post  164  of cap  144 . Cap  144  is inserted into opening  152  in an end of barrier  46  and attached to, e.g. by press fitting into, barrier  46 . Lower assembly  50  is similarly assembled, inserted into opening  128  in barrier  46 , and attached to barrier  46 . Barrier  46  is attached, e.g., by riveting, to hinges  20  and  70  (FIG. 1) which are attached to frame  12  e.g., by riveting.  
         [0045]    Referring to FIGS. 1-9, in operation, gate  10  is mounted between opposing surfaces and adjusted to fit snugly between the opposing surfaces. To adjust the fit between the opposing surfaces, assembly  38  is adjusted such that pad  182  is pressed firmly against one of the opposing surfaces. Coarse or “macro” adjustment of assembly  38  can be accomplished by pulling rod  178  or pushing rod  178  in directions  214  or  216 . This can be accomplished, e.g., by pulling or pushing on knob assembly  212 . When rod  178  is pulled or pushed in directions  214  or  216 , threads on threaded body  196  of rod  178  will interfere with tab  192 , and finger  190  will flex to allow tab  192  to move out of the way of the threads on threaded body  196 . Fine or “micro” adjustment of rod  178  in directions  214  or  216  can be accomplished by turning knob assembly  212  (e.g., using wrench  300 ) in an appropriate direction until assembly butts up against cap  172 . Further rotation of assembly  212  in this direction causes threads on nut  174  to mesh and interact with threaded body  196  to move rod  178  in direction  214 . Rotation of assembly  212  in the opposite direction will cause rod  178  to move in direction  216 . Each of the other three assemblies  38  on gate  10  can be adjusted in similar fashion. Knob assemblies  212  of assemblies  38  at the top of frame  12  are adjusted until arms  52  and  54  move inward (opposite to directions  57  and  59 ) such that angles  61  and  63  become approximately 90°.  
         [0046]    Wrench  300  is used to indicate that gate  10  has been properly secured. Handle  306  is pressed flat against surface  143  of bracket  18  and slid downward toward cross member  56  between bracket  18  and cap  142 . When this is done and assemblies  38  at the top of gate  10  are adjusted properly, handle  306  will contact and encounter resistance from (or will not fit between) bracket  18  and cap  142  due to the selected thickness  308  of handle  306 . Handle  306  thus provides a feeler gauge that indicates that gate  10  is properly secured between surfaces  11  and  13 . When gate  10  is properly secured, at least a desired minimum of static friction exists between pads  182  and surfaces  11  and  13 . For example, enough friction may exist such that a force of less than about 40 pounds against gate  10  will be insufficient to slide pads  182  relative to surfaces  11  or  13 . Also, when gate  10  is properly secured, pins  142  will be sufficiently received within recesses  138 , when gate  10  is in closed position  19 , to inhibit undesired opening of gate  10 . Assemblies  38  can be adjusted to securely fit gate  10  within passageways of about 29 inches to about 34 inches wide.  
         [0047]    If gate  10  is in a locked position (FIGS. 1 and 7), with door  14  in the closed position  19  and pins  122  and  142  in recesses  118  and  138 , door  14  can be moved to an open position by pressing on foot pedal  16  and concurrently pressing on door  14 . To remove the pins  142  and  122  from their respective recesses  138  and  118  to unlock door  14 , foot pedal  16 , foot pedal support  42 , and linkage  34  provide an actuator for actuating engagement and relative motion of the camming surfaces  121 ,  168 ,  141 , and  148 . Foot pedal  16  is pressed, e.g., by stepping on foot pedal  16 . When a downward force is exerted on foot pedal  16  that exceeds the required force to compress spring  36  (FIGS. 2 and 3), foot pedal  16  will move downward. This also causes linkage  34 , and therefore also bracket  18 , to move downward. Foot pedal camming surface  121  (FIG. 5) will slide against camming surface  168  (FIG. 2) and push pin  122  toward pivot axis  74 , out of recess  118 , and onto flat surface  123  (FIG. 5). Similarly, camming surface  141  will slide against camming surface  148  of pin  142 , pushing pin  142  out of recess  138  of bracket  18  and onto flat surface  143  as shown in FIG. 8. With pins  122  and  142  no longer in recesses  118  and  138 , door  14  is in an unlocked position (FIG. 8) and very little force is needed to move door  14  toward open positions  22  or  24 . The user presses against door  14 , e.g., against pad  40 , to pivot door  14  toward an open position.  
         [0048]    If door  14  is in an open position, door  14  can be rotated to the closed position  19  and automatically secured or locked in the closed position  19 . Foot pedal  16 , foot pedal support  42  (FIG. 2), linkage  34  (FIGS. 2 and 3), bracket  18 , and assemblies  48  and  50  (FIG. 2), form a lock for securing door  14  in closed position  19  with respect to frame  12 . Door  14  is moved, e.g., by pushing pad  40 , toward the closed position  19 . As door  14  is rotated from open position  22  toward closed position  19 , camming surfaces  148  and  168  of pins  142  and  162  engage with and slide against camming surface  219  (FIG. 6) of bracket  18  and camming surface  220  (FIG. 5) of foot pedal  16 , pushing pins  142  and  122  toward pivot axis  74 . When door  14  reaches closed position  19 , pins  142  and  122  are spring biased into recesses  138  and  118  respectively. Once pins  142  and  122  are in recesses  138  and  118 , door  14  is in a locked position and is substantially prevented from pivoting toward an open position unless foot pedal  16  is pressed with a sufficient force to compress spring  36 . Similarly, when door  14  is in open position  24 , door  14  can be rotated to closed position  19 , with engaging surfaces  148  and  168  sliding against and engaging with camming surfaces  218  (FIG. 6) and  222  (FIG. 5) of bracket  18  and foot pedal  16 , respectively.  
         [0049]    Other embodiments are within the scope and spirit of the appended claims. For example, extension arms can be provided to allow gate  10  to be secured in passageways larger than 34 inches.

Summary:
An apparatus includes a pair of frame members adapted for mounting to opposing surfaces of a passageway. A door is mounted to at least one of the frame members for movement between a closed position, in which the door and frame members substantially traverse the passageway, and an open position, in which a portion of the passageway is free of the door and frame members, the portion being large enough to permit passage of an adult therethrough. A lock is coupled to at least one of the frame members and adapted to retain the door in the closed position, the lock including an actuator adapted to release the lock to permit movement of the door from the closed position toward the open position upon application to the actuator of a force of at least a predetermined weight of a child.