You are an expert at summarizing long articles. Proceed to summarize the following text:

You are an expert at summarizing long articles. Proceed to summarize the following text: 
Japanese Patent Application No. 2012-277024 filed on Dec. 19, 2012 is hereby incorporated by reference in its entirety. 
     BACKGROUND 
     The present invention relates to a gate apparatus that can be opened and closed without using a hand. 
     A gate that restricts passage of a pet, and a gate that restricts access of a child to a dangerous area, have been known. US-A-2001/0000556 discloses a gate that is provided with a foot pedal that cannot be operated by a child. 
     However, the foot pedal disclosed in US-A-2001/0000556 is merely used to release the locked state of the gate, and does not open the gate forward. 
     JP-A-2004-57685 discloses a child safety fence that is configured so that a knee plate is provided above a pedal, and a gate can be opened forward with a knee while operating the pedal. 
     However, the pedal disclosed in JP-A-2004-57685 is also merely used to release the locked state of the gate. 
     SUMMARY 
     The invention may provide a gate apparatus that exhibits excellent operability, and is configured so that the locked state of a gate is released, and a force that opens the gate is applied by merely operating a pedal. 
     According to one aspect of the invention, there is provided a gate apparatus comprising: 
     a frame that is approximately in a shape of a letter “U”; 
     a gate that opens forward or backward from a closed position at which the gate is disposed inside the frame; 
     a rotational support device that supports one side of the gate so that the gate rotates and moves upward relative to the frame; 
     a locking device that locks the gate at the closed position; and 
     a pedal device that unlocks the locking device to open the gate, 
     the pedal device including a pair of pedals that are disposed on a front side and a back side of the gate, and a push-up member that is linked to the pair of pedals, and 
     the push-up member including a push-up surface that tilts when one of the pair of pedals is operated, the push-up surface tilting so that the push-up surface moves upward and comes in contact with the gate on a side closer to one of the pair of pedals that has been operated, and applying a push-up force and a rotation force to the gate. 
     The expression “opens forward or backward” used herein means that one side of the gate is rotatably supported, and the gate can be opened in the direction into which the user is making his way. 
     According to one aspect of the invention, when the front pedal is operated using a foot, the push-up surface of the push-up member tilts so that the front side of the push-up surface moves upward. The gate is moved upward by the tilted surface (push-up surface), and a rotation force that rotates the gate forward is applied to the gate due to the tilted surface (push-up surface). The locking device is released when the gate (that is supported by the rotational support device so that the gate can move upward and rotate) is moved upward due to the push-up force, and opened due to the rotation force. 
     Since the gate apparatus according to one aspect of the invention is configured so that the locked state is canceled when the gate is moved upward, the locked state can also be canceled, and the gate can be opened even when the gate is moved upward using a hand without operating the pedal. 
     Since the gate apparatus according to one aspect of the invention is configured so that the gate is opened by operating the pedal, the pair of pedals may respectively be biased to move downward when a force equal to or larger than 200 N has been applied, in order to prevent a situation in which the pedal is operated by a large dog or a child. 
     It is preferable to design the gate apparatus so that the pedal moves when an operation force (biasing force) equal to 200 to 300 N has been applied (i.e., a force that is normally applied by an adult). 
     An arbitrary structure may be employed for the device for which the locked state is canceled when the gate is moved upward. 
     For example, the locking device may include an upper locking device that is provided in an upper area on the other side of the gate, 
     the upper locking device may include an upper locking pin that is biased to protrude from one of the gate and the frame, and an upper locking recess that is provided in the other of the gate and the frame, and 
     an upper side of an inner surface of the upper locking recess may define a tilted surface. 
     In the gate apparatus, 
     the locking device may include a lower locking device that is provided to a bottom of the gate, and the lower locking device may include a lower locking pin that is biased to protrude from one of the gate and the frame, and a lower locking recess that is provided in the other of the gate and the frame. 
     In the gate apparatus, 
     the rotational support device may include a tilted receiving surface that is provided on a side of the frame, and a tilted sliding contact surface that is provided on a side of the gate, the tilted sliding contact surface may be placed on the tilted receiving surface from above, and 
     the tilted receiving surface and the tilted sliding contact surface may come in surface contact with each other at a downward angle toward the gate when the gate is set to the closed position. 
     According to the above configuration, the gate does not move downward when the gate is open since the tilted receiving surface and the tilted sliding contact surface come in surface contact with each other. When a force that closes the gate from the open state is applied to the gate, the gate closes automatically to the closed position due to the weight of the gate and surface contact between the tilted receiving surface and the tilted sliding contact surface. 
     In the gate apparatus, the rotational support device may further include a spring that applies a force that causes the tilted sliding contact surface to come in contact with the tilted receiving surface, the spring may be compressed when the gate moves upward. According to the above configuration, the downward biasing force of the spring that has occurred when the gate has moved upward can be used to allow the gate to close automatically in addition to the weight of the gate. 
     In the gate apparatus, the push-up member may be disposed between the pair of pedals, and may be linked to the pair of pedals. Since the push-up member tilts so that the push-up surface moves upward on the side of the operated pedal, the push-up force that moves the gate upward, and the rotation force that opens the gate forward, can be applied to the gate by utilizing the tilted surface (push-up surface). This makes it possible to easily open the gate forward. 
     When the push-up member is linked to the pair of pedals at a position between the pair of pedals, the gate can be opened forward and backward using a common push-up member. It is also possible to implement a simple structure while ensuring excellent operability. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  illustrates an example of the structure of a gate apparatus according to one embodiment of the invention, and  FIG. 1B  is a cross-sectional view taken along the line A-A illustrated in  FIG. 1A . 
         FIG. 2A  is a plan view illustrating the gate apparatus in a state in which the gate is closed, and  FIG. 2B  is a plan view illustrating the gate apparatus in a state in which the gate is opened by operating the pedal. 
         FIG. 3A  is an enlarged view illustrating the pedal device, and  FIG. 3B  is a perspective view illustrating the pedal device. 
         FIG. 4  is a bottom view illustrating the pedal device. 
         FIG. 5A  is a cross-sectional views taken along the line B-B in  FIG. 4  illustrating a state in which the gate is closed,  FIG. 5B  is a cross-sectional views taken along the line B-B in  FIG. 4  illustrating a state in which the push-up member is tilted by operating the pedal to open the gate, and  FIG. 5C  is a cross-sectional views taken along the line B-B in  FIG. 4  illustrating a state in which the push-up member is tilted by operating the pedal to open the gate. 
         FIG. 6A  is an enlarged view illustrating the rotational support device,  FIG. 6B  illustrates an example of the structure of the rotational support device on the side of the support vertical frame,  FIG. 6C  illustrates the biasing pin, and  FIG. 6D  illustrates an example of the structure of the rotational support device on the side of the gate. 
         FIG. 7A  illustrates a state in which the gate is rotatably supported by the support vertical frame,  FIG. 7B  illustrates a state when inserting the biasing pin,  FIG. 7C  illustrates a state in which the biasing pin is inserted, and  FIG. 7D  is a view illustrating a state in which a downward biasing force is applied when the gate is moved upward. 
         FIG. 8A  illustrates a state in which the gate is closed,  FIGS. 8B and 8C  illustrate a state in which the gate is opened to some extent, and  FIGS. 8D and 8E  illustrate a state in which the gate is opened by 90°. 
         FIG. 9A  is an enlarged view of the upper locking device illustrating the locked state,  FIG. 9B  is an enlarged view of the upper locking device illustrating a state in which the gate moves upward, and the locked state is canceled (i.e., the locking pin is pushed backward),  FIG. 9C  is an enlarged view of the upper locking device illustrating a state in which the gate is open, and  FIG. 9D  is a perspective view illustrating the locking recess. 
         FIG. 10A  is an enlarged view of the lower locking device illustrating the locked state,  FIG. 10B  is an enlarged view of the lower locking device illustrating the locked state,  FIG. 10C  is an enlarged view of the lower locking device illustrating a state in which the gate moves upward so that the locked state is canceled, and  FIG. 10D  is an enlarged view of the lower locking device illustrating the motion when the gate is closed. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     A gate apparatus according to one embodiment of the invention may be widely used in various fields as a hinged gate opening/closing apparatus. 
     For example, the gate apparatus according to one embodiment of the invention may be used as a gate that restricts passage of a pet, a gate that restricts access of a child, and the like. 
     The gate apparatus according to one embodiment of the invention is described below taking an example in which the gate apparatus is used to block a passageway. 
     Note that the gate apparatus according to one embodiment of the invention may also be used as an opening/closing gate of a pet circle or the like, or a gate apparatus of a fence that is placed in a passageway. 
       FIG. 1A  illustrates an example of the structure of the gate apparatus according to one embodiment of the invention. 
     As illustrated in  FIG. 1A , a frame  20  that is approximately in the shape of the letter “U” is secured between the walls of a passageway, and a gate  10  is disposed inside the frame  20 . 
     The frame  20  includes a base section  21  that is disposed along the floor surface in the direction that crosses the passageway, and a support vertical frame  22  and a vertical frame  23  that extend upward from either side of the base section  21 , and is provided upright to form an opening (passageway) that is generally in the shape of the letter “U”. 
     The support vertical frame  22  is provided with an auxiliary frame  22   a , and fixtures  61  are respectively screwed into the upper part and the lower part of the auxiliary frame  22   a . The support vertical frame  22  is secured on the wall by adjusting the number of turns to press the fixture  61  against the wall. 
     An adjuster  62  that has an internal thread section into which an external thread section  61   a  of the fixture  61  is screwed, is provided to adjust the thrust amount of the fixture  61 . 
     The vertical frame  23  is similarly provided with a fixture  61  and an adjuster  62  via an auxiliary frame  23   a.    
     The support vertical frame  22  and the vertical frame  23  can be secured on the walls on either side of the passageway by turning the upper and lower adjusters  62  to adjust the thrust amount of the fixtures  61 . 
     Note that the frame  20  may be secured and installed by an arbitrary method as long as the frame  20  can be disposed approximately in the shape of the letter “U”. 
     The gate  10  has a configuration in which the ends of an upper crosspiece  11  and a lower crosspiece  12  are connected via a right vertical crosspiece  13  and a left vertical crosspiece in the shape of a frame, and a lattice is formed inside the frame using a wire rod. Note that the gate  10  may have a panel instead of a lattice. 
     The end of the upper crosspiece  11  and the end of the lower crosspiece  12  positioned on one side of the gate  10  (left side in  FIG. 1A ) are rotatably supported by the frame  20 . For example, the end of the upper crosspiece  11  is rotatably supported by the support vertical frame  22  via a rotational support device  40 . The end of the lower crosspiece  12  is supported by the base section  21  via a rotation pin  46  (see FIGS.  1 A and  3 A). 
     The rotational support device  40  and the rotation pin  46  allow the gate  10  to move upward by a specific amount so that the gate  10  can be moved upward using a pedal device  30 , or can be moved upward with a hand. 
     An upper locking device  50  is provided between the end of the upper crosspiece  11  and the upper end of the vertical frame  23  positioned on the other side of the gate  10  (right side in  FIG. 1A  (open side)). The gate  10  can have a lower locking device  60  that is positioned between the bottom surface of the lower crosspiece  12  and the base section  21 . 
     As illustrated in  FIG. 1B  (cross-sectional view taken along the line A-A in  FIG. 1A ), the pedal device  30  is provided to extend across the base section  21 . As illustrated in  FIG. 2A  (plan view), the pedal device  30  includes pedals  34  and  35  that are positioned on the front side and the back side of the gate  10  (upper crosspiece  11 ). When the pedal  34  or  35  is operated, the gate  10  is moved upward, and the upper locking device  50  and the lower locking device  60  are unlocked, so that the gate  10  opens. 
     When the pedal  35  is operated when the gate  10  is set to a closed state in which the gate  10  (upper crosspiece  11 ) is positioned inside the frame  20  (see  FIG. 2A ), the gate  10  (upper crosspiece  11 ) opens forward to move away from the operated pedal  35  (see  FIG. 2B ). 
       FIGS. 6A to 8E  illustrate an example of the structure of the rotational support device  40 . 
     As illustrated in  FIG. 6A , the rotational support device  40  includes a receiving section  41  that is positioned on the side of the support vertical frame  22 , and a rotation section  42  that is positioned on the side of the upper crosspiece  11  of the gate  10 . 
     As illustrated in  FIG. 6B , the receiving section  41  includes a pivot shaft  41   b  that is provided upright from the bottom of a pivot recess  41   a . The bottom of the pivot recess  41   a  defines a tilted receiving surface  41   d  that is tilted toward the gate  10 . The upper end of the pivot recess  41   a  is tilted in parallel to the tilted receiving surface  41   d , and a locking recess  41   c  is formed in the vicinity of the uppermost part of the upper end of the pivot recess  41   a.    
     As illustrated in  FIG. 6D , the rotation section  42  includes a tubular section  42   a  that is inserted into the pivot recess  41   a , and a locking rib  42   d  that is provided to the tubular section  42   a . The locking rib  42   d  is provided on the side surface of the tubular section  42   a  that is positioned on the open side of the gate  10 . 
     The lower end face of the tubular section  42   a  defines a tilted sliding contact surface  42   b  corresponding to the tilted receiving surface  41   d  that is formed at the bottom of the pivot recess  41   a . The lowermost position of the tilted sliding contact surface  42   b  is situated on the open side of the gate  10  (i.e., on the side of the passageway). 
     As illustrated in  FIG. 7A , the tubular section  42   a  of the rotation section  42  is pivotally fitted (inserted) into the pivot recess  41   a . As illustrated in  FIG. 7B , a biasing pin  43  is inserted into the pivot shaft  41   b  in a state in which the pivot shaft  41   b  is positioned inside a hollow section  42   c  of the tubular section. 
     As illustrated in  FIG. 6C , the biasing pin  43  includes a head  43   a  having a diameter larger than that of the pin section, and an insertion groove  43   b  for a C-ring  45  that is formed at the end of the pin section, and a spring  44  is fitted to the pin section. 
     As illustrated in  FIG. 7B , the biasing pin  43  is inserted into the pivot shaft  41   b  from above so that the lower end of the spring  44  comes in contact with the step portion of a step recess  42   e . As illustrated in  FIG. 7C , the C-ring  45  is inserted into the insertion groove  43   b  formed at the end of the pin section. 
     The C-ring  45  prevents the biasing pin  43  from falling out. 
     The gate  10  is biased downward by the spring  44 . 
     The tilted receiving surface  41   d  of the receiving section  41  comes in sliding contact with the tilted sliding contact surface  42   b  of the rotation section  42 . As illustrated in  FIGS. 8B and 8C , when the gate  10  is opened to some extent, the tilted sliding contact surface  42   b  of the rotation section  42  rotates while coming in sliding contact with the tilted receiving surface  41   d  of the pivot recess  41   a , and the gate  10  moves upward against the weight of the gate  10  and the downward biasing force applied by the spring  44 . 
     As illustrated in  FIGS. 8D and 8E , when the gate  10  is further opened so that the rotation angle reaches 90°, the locking rib  42   d  of the rotation section  42  is locked by the locking recess  41   c  of the receiving section  41 , and the gate  10  is held in the 90° open state. In this case, the spring  44  is compressed to a maximum extent. 
     When the gate  10  is closed to some extent so that the rotation angle decreases from 90°, the locking rib  42   d  is removed from the locking recess  41   c , and the rotation force and the weight of the gate  10  are applied to the gate  10 . The downward biasing force of the spring  44  is also applied to the gate  10 . Therefore, the gate  10  rotates and moves downward along the tilted receiving surface  41   d , and closes automatically. 
       FIGS. 9A to 9D  illustrate an example of the structure of the upper locking device  50 . 
     As illustrated in  FIG. 9A , the upper locking device  50  includes a locking receiving section  51  and a locking section  52 . The locking section  52  that is provided at the end of the upper crosspiece  11  includes a locking pin  52   a  that is biased by a spring  52   b  in the direction in which the locking pin  52   a  protrudes from the end of the locking section  52 , and the locking receiving section  51  is provided on the upper end of the vertical frame  23 . 
     As illustrated in  FIGS. 9A and 9D , the locking receiving section  51  includes a locking recess  51   a , and a tilted surface  51   b  that is defined by the upper side of the inner surface of the locking recess  51   a.    
     Therefore, when the gate  10  moves upward (see  FIG. 9B ), the locking pin  52   a  moves along the tilted surface  51   b , and the gate  10  is released from the locked state, and rotates (see  FIG. 9C ). 
     Note that the locking pin may be provided to the frame, and the locking recess may be provided to the gate, differing from the above example. 
       FIGS. 10A to 10D  illustrate an example of the structure of the lower locking device  60 . 
     As illustrated in  FIG. 10A , the lower locking device  60  includes a locking receiving section  61  and a locking section  62 . The locking section  62  that is provided to the bottom of the lower crosspiece  12  includes a projection pin  62   a  that is biased downward by a spring  62   b.    
     The locking receiving section  61  that is provided to the base section  21  includes a locking recess  61   a , and slope sections  61   b  that are provided on the front side and the back side of the locking recess  61   a . The slope section  61   b  is tilted downward from the upper opening of the locking recess  61   a.    
     When the gate  10  moves upward from the position illustrated in  FIG. 10B , the locked state of the lower locking device  60  is canceled (see  FIG. 10C ). When the gate  10  closes, the projection pin  61   a  is guided upward along the slope section  61   b  (see  FIG. 10D ), and enters the locking recess  61   a  (see  FIG. 10B ). 
     An example of the structure of the pedal device  30  is described below with reference to  FIGS. 3A to 5C . 
     The pedal device  30  includes a pair of mounting plates  31  and  32  that are opposite to each other, and a connection section  33  that is approximately in the shape of an inverted letter “U”, and connects the center area of the pair of mounting plates  31  and  32 . The pedal device  30  is secured on the base section  21  using a fixture  33   a  (e.g., bolt or nut) so that the base section  21  is inserted into the connection section  33 . 
     The pedals  34  and  35  are rotatably supported by shafts  34   b  and  35   b , respectively, at a position between the mounting plates  31  and  32  on the front side and the back side of the gate  10 . 
     As illustrated in  FIGS. 5A to 5C  (cross-sectional views taken along the line B-B in  FIG. 4 ), the pedals  34  and  35  are formed approximately in the shape of the letter “L”, and respectively include stepping surfaces  34   a  and  35   a  that extend away from the base section  21  on the front side and the back side of the gate  10 , and action sections  34   d  and  35   d  that extend downward from the shafts  34   b  and  35   b.    
     The pedal device  30  includes a push-up member  36  that is linked to the pedals  34  and  35 . The push-up member  36  is disposed between the pedals  34  and  35 , for example. The push-up member  36  is linked to the pedals  34  and  35  via link members  34   e  and  35   e.    
     More specifically, the push-up member  36  includes a push-up surface  36   a  having a flat upper surface, and side elements  36   b  and  36   c  that extend downward from either side of the push-up surface  36   a , and is approximately formed in the shape of an inverted letter “U”. Channel-like connection sections  236   b  and  236   c  are formed on the lower end of the side elements  36   b  and  36   c . One end of the link member  34   e  and one end of the link member  35   e  are rotatably supported by the connection sections  236   b  and  236   c  using axial attachment sections  136   b  and  136   c , respectively. The other end of the link member  34   e  and the other end of the link member  35   e  are rotatably supported by the action sections  34   d  and  35   d  of the pedals  34  and  35  using axial attachment sections  34   c  and  35   c , respectively. 
     The stepping surfaces  34   a  and  35   a  of the pedals  34  and  35  are respectively biased by coil springs  37  and  38  so that the stepping surfaces  34   a  and  35   a  return to the original approximately horizontal state (see  FIGS. 5A to 5C ). 
     The coil springs  37  and  38  are provided so that one end  37   a  and one end  38   a  respectively come in contact with the back side of the pedal  34  and the back side of the pedal  35 , and the other end  37   b  and the other end  38   b  come in contact with the connection section  33 . 
     The biasing force applied by the coil springs  37  and  38  is set so that the stepping surfaces  34   a  and  35   a  of the pedals  34  and  35  move downward when a force of 200 to 300 N has been applied to the pedals  34  and  35 . 
     This is advantageous from the viewpoint of safety since the pedal cannot be operated by even a large dog or a child. 
     The pedal device  30  is configured as described above. As illustrated in  FIGS. 5B and 5C , when the pedal  34  or  35  is operated, the push-up surface  36   a  of the push-up member  36  is moved upward on the side of the operated pedal, and is tilted forward. 
     Therefore, the push-up force and the forward rotation force are applied to the gate  10  (lower crosspiece  12 ) (see the arrows in  FIGS. 5B and 5C ). 
       FIGS. 2B ,  5 B, and  5 C illustrate a state in which the pedal  35  is operated. When the pedal  34  is operated, the gate  10  opens in the reverse direction. 
     After the push-up force and the rotation force have been applied to the gate  10  by the pedal device  30  in a state in which the push-up surface  36   a  comes in contact with the gate  10  (see  FIG. 5B ), the gate  10  is moved upward and rotated by the rotational support device  40  due to the inertial force of the gate  10  or an external force that further opens the gate  10 , and is opened. 
     Although only some embodiments of the present invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within scope of this invention.

Summary:
A gate apparatus includes a frame that is approximately in a shape of a letter “U”, a gate that opens forward or backward, a rotational support device that supports the gate so that the gate rotates and moves upward relative to the frame, a locking device that locks the gate at a closed position, and a pedal device that unlocks the locking device. The pedal device includes a pair of pedals on the both sides of the gate, and a push-up member that is linked to the pair of pedals. The push-up member includes a push-up surface that tilts when the pedal is operated. The push-up surface tilts so that the push-up surface moves upward and comes in contact with the gate on the side closer to the pedal that has been operated, and applies a push-up force and a rotation force to the gate.