Abstract:
A closing device for a toilet unit includes a slave member connected to a toilet cover, a motor, and a switching mechanism that mechanically connects or disconnects the motor from the slave member during closing of the cover. When the motor rotates to move the toilet cover from an open position to a partially closed position, the switching mechanism allows the slave member to move in response to rotation of the motor. After the toilet cover reaches the partially closed position, the mechanical link between the slave member and the motor provided by the switching mechanism is released such that the toilet cover falls freely under its own weight to the closed position independent of the motor. Preferably, the device includes a driving member coupled between the motor and the switching mechanism and operable to move the slave member. The motor rotates in the reverse direction to return the driving member to a position corresponding to the open position of the toilet cover such that during opening of the toilet cover by a user, the slave member is mechanically disconnected from the driving member to reduce the amount of force required to open the toilet cover.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates to a toilet cover opening/closing device by which the toilet cover in the fully opened state is moved by a motor to a point in the closing direction and then rotates until it is in the fully closed state being initiated by the weight of the toilet cover itself.  
         BACKGROUND OF THE INVENTION  
         [0002]    The present invention relates to a toilet cover opening/closing device by which the toilet cover in the fully opened state is moved by a motor to a point in the closing direction and then rotates until it is in the fully closed state being initiated by the weight of the toilet cover itself.  
           [0003]    When one visits a toilet and sees a toilet cover wide open, he or she will not be impressed with it and it is not sanitary either. Moreover, when a heater is built into the toilet seat, power consumption increases during the time the toilet cover is left open. To solve these problems, a variety of toilet cover opening/closing devices for automatically closing a wide-open toilet cover have been proposed.  
           [0004]    Japanese Laid-open patent application No. H11-76103 is an example that discloses a toilet cover in which a motor moves a wide-open toilet cover to a point in the closing direction, and then, the toilet cover rotates (to a fully closed position) by its own weight. Here, gears mechanically connect all the components, motor through the rotary shaft of the toilet cover, and a torque limiter, provided in the middle of the force transmission path, turns on a motor until the toilet cover starts rotating under its weight and automatically turns off the motor as soon as the toilet cover reaches the point at which the self-weight initiated rotational motion begins. Nonetheless, the moment of the toilet cover is larger than the torque generated by the torque limiter, idling the torque limiter. Nothing prevents the toilet cover from making the self-weight initiated rotational motion in the closing direction. Further, to prevent sudden closure of the toilet cover, the rotary shaft of the toilet cover is always connected to a shock absorber through gears to respond to the shock absorber.  
           [0005]    Japanese Laid-open patent application No. H11-76105 discloses another type in which a motor drives both a toilet cover and a shock absorber in an attempt to prevent a sudden closure of a toilet seat. As the toilet cover reaches the point where its self-weight initiates closing motion, the friction mechanism in the shock absorber breaks the rotational (closing) motion of the shock absorber itself to cause an idle spin until the timer stops the motor. In this mechanism, the toilet cover quietly closes due to the resistance from the shock absorber when the toilet cover makes the self-weight initiated rotary motion in the closing direction.  
           [0006]    Nevertheless, in light of the above problems of conventional technologies: the former type assumes an idle spin of the torque limiter every time the toilet cover makes an opening or closing motion, requiring an expensive torque limiter with very high durability. Further, the point where the magnitude of torque of the torque limiter exceeds the moment of the toilet cover is a point where the toilet cover initiates its self-weight rotational (closing) motion: the declination starting point fluctuates due to inconsistency of torque that the torque limiter provides or (an additional variable such as) a (textile or knit) cover attached to the toilet cover, complicating the method of controlling the motor. Further, when a user manually opens the toilet cover connected to a motor, he must always apply a force that is larger than the torque generated by the torque limiter. This adversely affects handling ease of the toilet cover.  
           [0007]    The former type assumes the shock absorber to rotatably support the toilet seat and toilet cover, as a result, the shock absorber is loaded with a large external force. To rotate the shock absorber itself, the joint between the guide portion in the rotation mechanism and the motor must be made very rigid. Moreover, a user manually opens the toilet cover initially taking advantage of the toilet cover&#39;s moment, which is the initial main load, however, he must apply a force large enough to overcome the friction mechanism built into the motor to rotate the shock absorber itself later. In this method, the torque suddenly increases in the middle of the motion. This also adversely affects the handling ease of the toilet cover.  
           [0008]    To overcome the above problems, it is desirable to provide an affordable toilet cover opening/closing device having a simple configuration with greatly improved handling ease thereof at the time of manual opening.  
         SUMMARY OF THE INVENTION  
         [0009]    As a means to solve the above problems, the present invention provides a toilet cover opening/closing device that comprises: a rotary shaft for moving the toilet cover; and a driving means for rotating the rotary shaft to provide a rotational motion to the toilet cover from an inclined starting position where the toilet cover starts rotating in the closing direction by its own weight. The driving means further comprises: a motor that is rotatable both clockwise and counterclockwise; a driving member that is connected to the output shaft end of the motor; a slave member that is connected to the rotary shaft end; and a switching mechanism mechanically connecting or disconnecting the driving member with the slave member. When the motor rotates clockwise to lift the toilet cover from the fully opened position to the inclined starting position, the switching mechanism allows the slave member to move in response to the driving member. After the toilet cover reaches the inclined starting position, the mechanical linkage between the driving member and the slave member is released. As a result, the slave member moves in accordance with the self-weight initiated rotary motion of the toilet cover independent if the driving member and the driving member returns to its fully opened position in the toilet cover independent of the slave member taking advantage of the motor&#39;s reversed spin.  
           [0010]    Assume that one wants to rotate the toilet cover that is kept wide open as a result of the motor&#39;s clockwise rotational motion in the closing direction. The driving member connected to the motor end and the rotary shaft end of the toilet cover are mechanically connected via a switching mechanism; the motor driving the rotational motion of the toilet cover in the closing direction. After the toilet cover reaches the point of self-weight initiated inclination, the switching mechanism mechanically disconnects the driving member and the slave member. In this configuration, the slave member being independent of the driving member can move in response to the self-weight initiated rotational motion of the toilet cover, and at the same time, the driving member being independent of the slave member returns to its original position, which is the fully opened position of the toilet cover. As a result, when a user manually opens the toilet cover, a responsive motion occurs at the slave member but not at the driving member connected to the output shaft end of the motor. The toilet cover can thus be closed with a minimum effort. In addition, the closure of the toilet cover can be minimal only by releasing the linkage between the driving member and the slave member. The method of controlling a motor can thus be made easy and the manufacturing of the mechanism can thus be cost effective.  
           [0011]    In this invention, the switching mechanism has a structure, for example, in which the driving member pushes the slave member to move the toilet cover from the fully opened position to the inclined starting position, wherein the slave member and the driving member do not interfere with each other as long as the toilet cover&#39;s self-weight initiates the motion of the slave member defined by the inclined starting position and the fully closed position.  
           [0012]    In this invention, the switching mechanism has a structure in which a groove is provided on the driving member in such a manner that a part of the slave member makes a relative linear motion therein to move in response to the driving member when the toilet cover moves from the fully opened position to the inclined starting position. The shape and length of the groove from one edge to the other edge is set so as to cause: (1) the motor&#39;s reversed spin providing the slave member with a rotational motion independent of the driving member after the toilet cover rotates from the fully opened position to an inclined starting position; and (2) the driving member is capable of returning to its original position independent of the slave member.  
           [0013]    In this invention, it is preferable that the toilet cover further comprises a shock absorber for applying a resisting force to the self-weight initiated rotational motion exercised in the closing direction such that the speed of the self-weight initiated rotational motion that occurs between the inclined starting position and ends in the fully closed position is slowed down. In this configuration, a large noise does not occur at the time the toilet cover makes the self-weight initiated rotational motion in the closing direction. In this way, the toilet cover will not be damaged either.  
           [0014]    For the motor of this invention, a stepping motor is preferable. This configuration causes the stepping motor to lose synchronism with the motion even though manual opening of the toilet cover interrupts the motor driven closing rotary motion. As a result, the user can open the toilet cover with little effort even though opening applies a force against the motor&#39;s spinning direction.  
           [0015]    In this invention, it is further preferable that the toilet cover further comprises a stopper that mechanically defines the original position and the end position of the driving member, which is in line with the rotational motion of the driving member that occurs between the fully opened position and the inclined starting position. In this configuration, when the motor driven closing motion of the toilet cover encounters an opening motion manually applied thereto resulting in displacement of the toilet cover from the target position that meets the duration of time the motor was on, the motor makes a reversed spin to initialize the position of the toilet cover utilizing the stopper. In this way, the next motion of the toilet cover can normally be driven. By controlling steps or a time, the toilet cover opening/closing device of the present invention thus accurately repeats the same motion all the time. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0016]    [0016]FIG. 1 is a diagram illustrating a toilet seat unit having a toilet cover opening/closing device of the present invention.  
         [0017]    [0017]FIG. 2 is a top view illustrating the external appearance of the toilet cover opening/closing device applied to the toilet seat unit of FIG. 1.  
         [0018]    [0018]FIG. 3 is a top view illustrating the layout of components in the toilet cover opening/closing device of FIG. 2.  
         [0019]    [0019]FIG. 4 is an extended (cross sectional) diagram illustrating a layout of the components of the toilet cover opening/closing device of FIG. 2.  
         [0020]    [0020]FIG. 5 (A), FIG. 5 (B), and FIG. 5 (C) are diagrams describing the operation of the toilet cover opening/closing device of an embodiment of the present invention; wherein FIG. 5 (A), FIG. 5 (B), and FIG. 5 (C) correspond to the fully opened position, an inclined starting position, and the fully closed position, respectively. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0021]    The toilet cover opening/closing device of the present invention is described herein with reference to the drawings.  
         [0022]    [0022]FIG. 1 is a diagram illustrating a toilet unit having a toilet cover opening/closing device of an embodiment of the present invention. FIG. 2 is a plan view illustrating the external appearance of the toilet cover opening/closing device of this embodiment. In light of each component arranged within the toilet cover opening/closing device, FIG. 3 is a top view illustrating the layout of the mechanism components and FIG. 4 is an expanded diagram of FIG. 3.  
         [0023]    Toilet  1  illustrated in FIG. 1 comprises: a toilet body  2 ; a water tank  3 ; and a toilet seat unit  4 . Toilet seat unit  4  generally comprises: a toilet seat  5 ; a toilet cover  6 ; and a body cover  7 . Body cover  7  is built into the toilet cover opening/closing device  10  as illustrated in FIG. 2. Toilet cover opening/closing device  10  has projections having a toilet seat lever  11  connected to toilet seat  5 ; and a rotary shaft  20  pivotally connected to toilet cover  6  in a manner that toilet seat lever  11  and rotary shaft  20  project outward from unit casing  30 .  
         [0024]    Toilet opening/closing device  10  motor drives toilet cover  6  with a fully opened position indicated by a solid line LA to an inclined position marked by a dotted line LB in the middle of the closing motion, where toilet cover  6  enters self-weight initiated rotational motion all the way to the fully closed position where it rests on toilet seat  5 .  
         [0025]    As illustrated in FIGS. 3 and 4, toilet cover opening/closing device  10  comprises an oil damper  21  to accommodate seat lever  11  such that toilet cover  6  does not fall all of a sudden even though the user lets go of toilet seat  5  to return toilet seat  5  to rest on toilet body  2 .  
         [0026]    Toilet cover opening/closing device  10  comprises another oil damper  21  to accommodate rotary shaft  20  as well such that toilet cover  6  does not fall all of a sudden even though the user lets go of toilet seat  5  in an attempt to return toilet cover  6  back onto toilet seat  5 .  
         [0027]    In unit casing  30  of toilet opening/closing device  10 , a disk-shaped coupling gear  40  (slave member) is connected to rotary shaft  20  toward the base end thereof via (through) an E-shaped stop ring  13 . In unit casing  30 , a stepping motor  60 , the driving source, that can rotate in a reversed manner is arranged to rotate toilet cover  6  via (through) coupling gear  40 .  
         [0028]    Unit casing  30  comprises: an upper casing  36  and a lower casing  37 . The motor casing and the board accommodating stepping motor  60  are secured utilizing circular ribs on upper casing  36  and groove-like ribs (on lower casing  37 ).  
         [0029]    On the power transfer path defined by the output shaft of stepping motor  60  and the coupling gear  40  are arranged pinion  61  fixed onto the output shaft of stepping motor  60 ; first gear  71  meshed with pinion  61 ; second gear  72  meshed with the pinion on first gear  71 ; third gear  73  meshed with the pinion of second gear  72 ; and sector gear  50  meshed with the pinion of third gear  73 . In the space defined by sector gear  50  and coupler gear  40  is arranged a switching mechanism  80  that mechanically connects or disconnects sector gear  50  with coupler gear  40 . Note that the circular shape of the base of sector gear  50  is concentric to and leveled with coupler gear  40  such that the circular portion can rotate around the common center axis.  
         [0030]    In switching mechanism  80  of this embodiment, on the surface of gear sector  50  are provided two grooves  51  of circular concavity in such a manner that they are symmetric to and concentric to the central axis of rotation wherein the face of sector gear  50  faces coupling gear  40 . On sector gear  50  toward coupling gear  40  are formed two projections  41  that fit into each of the two grooves  51 .  
         [0031]    Now, FIG. 3 illustrates toilet cover  6  in the fully opened position as indicated by a solid line LA in FIG. 1. When toilet cover  6  is in the fully opened position, one of each edges  511  or  512  contacts projection  41  wherein edge  511  is provided at the clockwise end of groove  51  while edge  512  is provided at the counterclockwise end of groove  51 .  
         [0032]    A cam unit is provided at the lower end of coupling gear  40  and lever  91  with a cam follower, arranged at the side of coupling gear  40 . Lever  91  is rotatably arranged around the shaft and has a contact point that contacts cam surface  45  provided on the outer circumference of coupling gear  40 . Lever  91  is further coupled with one end of coil spring  92  at the opposite end of the contact point. The other end of coil spring  92  is attached to projection  41  in the casing. The contact point of lever  91  being pressed by tension spring  92  thus elastically contacts cam surface  45 .  
         [0033]    Magnet  96  is fixed onto one edge of lever  9  and a sensor  97  made of a hole IC packaged in circuit board  99  (FIG. 4) is provided at a point opposite to magnet  96 . As coupling gear  40  rotates from the state illustrated in FIG. 3, lever  91  rocks in response to the rotation. This motion changes the position of magnet  96  that is fixed onto lever  91 . Sensor  97  detects such a motion (of magnet  96 ). This characteristic allows sensor  97  to detect the angle or position of coupling gear  40 , in other words, whether toilet cover  6  is opened or closed. Cam surface  45  is concave at 30 degrees, at which sensor  97  switches the output signal before the fully closed position.  
         [0034]    In the switching mechanism  80  of toilet cover opening/closing device  10  configured in the manner described above, groove  51  is provided within a range of 157 degrees and projection  41  occupies about 30 degrees, leaving 127 degrees for idling between groove  51  and projection  41 .  
         [0035]    In this embodiment, toilet cover  6  is set up (programmed) as follows: in the fully opened position, toilet cover  6  moves 30 degree backward viewed from the upright position. As stepping motor  60  rotates toilet cover  6  by 60 degrees in the closing direction, toilet cover  6  reaches the inclined starting position, which is an additional 30 degrees forward, and then, the self-weight initiated rotational motion brings toilet cover  6  to the fully closed position.  
         [0036]    On the inner surface of unit casing  30  are provided two stoppers  31  and  32  that mechanically define the original position and the end position of sector gear  50  as sector gear  50  rotates from the fully opened position to the inclined starting position.  
         [0037]    [0037]FIG. 5 (A), FIG. 5 (B), and FIG. 5 (C) are diagrams describing the operation of the toilet cover opening/closing device of this embodiment, each FIG. 5 (A), FIG. 5 (B), and FIG. 5 (C) corresponding to the fully opened position, the declination starting position, and the fully closed position respectively.  
         [0038]    In toilet cover opening/closing device  10  of this embodiment, when toilet cover  6  is in the fully opened position, as illustrated in FIG. 5 (A), projection  41  of coupling gear  40  is positioned near one end  511  of groove  51  provided on sector gear  50  and cam surface  45  pushes away the contact point of lever  91  such that magnet  96  is positioned in proximity of sensor  97 .  
         [0039]    In this state, when sensor  97  in toilet cover opening/closing device  10  of the toilet seat unit  4  detects that toilet cover  6  is kept open clockwise without being used for a given time period, stepping motor  60  rotates by a given number of steps or for a given time period. As a result, the torque of the output shaft is transmitted to first gear  71 , second gear  72 , third gear  73 , and sector gear  50  such that sector gear  50  rotates 60 degrees counterclockwise as illustrated in FIG. 5 (B). This is the end point for sector gear  50 . During the rotation, one end  511  of groove  51  pushes projection  41  of coupling gear  40  in groove  51  of sector gear  50  while coupling gear  40  rotates 60 degrees and toilet cover  6  rotates to reach the inclined starting position, which is 30 degrees toward the front.  
         [0040]    From the above state, toilet cover  6  reaches the fully closed position by its own weight. In response to this motion, projection  41  of coupling gear  40  further rotates 60 degrees counterclockwise as illustrated in FIG. 5 (C). However, as a sufficient idle space is provided in the space between groove  51  on sector gear  50  and projection  41 , sector gear  50  and projection  41  do not interfere with each other. Between sector gear  50  and coupling gear  40 , only coupling gear  40  corresponds to the motion of toilet cover  6 .  
         [0041]    Further, cam surface  45  provided on coupling gear  40  also rotates counterclockwise during the self-weight initiated rotary motion of toilet cover  6 , as a result, lever  91  rotates causing magnet  96  to be distanced from sensor  97  at a point 30 degrees above the fully closed position. The signal output from sensor  97  is thus switched. The output signal reaches sensor  97 , which detects the closure of toilet cover  7 .  
         [0042]    While toilet cover  6  rotates to the fully closed position, stepping motor  60  spinning in a reversed mode rotates sector gear  50  by 60 degrees counterclockwise to return sector gear  50  to its original position as illustrated in FIG. 5 (C). Given a sufficient idle space between groove  51  on sector gear  50  and projection  41 , sector gear  50  and projection  41  do not interfere with each other in this case either. Between sector gear  50  and coupling gear  40 , only coupling gear  40  returns to its original position.  
         [0043]    As a user manually opens toilet cover  6  from the state illustrated in FIG. 5 (C), coupling gear  40  rotates in response to the rotary motion of toilet  6  from the position of FIG. 5 (C) to that of FIG. 5 (A). During the rotation, sector gear  50  and projection  41  do not interfere with each other. Between sector gear  50  and coupling gear  40 , that are linked to stepping motor  60  or an array of gears respectively, only coupling gear  40  returns to its original position.  
         [0044]    The toilet cover opening/closing device  10  thus described in the above embodiment drives toilet cover  6  by stepping motor  60  via (through) sector gear  50 , coupling gear  40 , and rotary shaft  20 . Toilet cover  6  rotates 60 degrees from the fully opened position to the inclined starting position, then, it falls by the weight of toilet cover  6  itself. During the closing motion, the rotary motion responds to the torque generated by the weight of toilet cover  6  which is independent of sector gear  50 . Afterwards, toilet cover  6  is rotated by motor  60  from the fully opened position to the inclined starting position. Alternately, motor  60  may be reversed as toilet cover  6  rotates from the fully opened position to the inclined starting position such that sector gear  50  is returned to its original position in a manner such that the motion of sector gear  50  is independent of coupling gear  40 . Yet alternately, when a user manually opens toilet cover  6 , coupling gear  40  returns to its original position in response to the rotary motion of toilet cover  6 . However, sector gear  50  and projection  41  do not interfere with each other during the rotation, eliminating the change of overloading sector gear  50  connected to stepping motor  60  or an array of gears. The force required for manually opening toilet cover  6  is thus minimized.  
         [0045]    Moreover, the mechanism configured in the above manner helps to mechanically connect or disconnect sector gear  50  and coupling gear  40  utilizing groove  51  provided on sector gear  50  and projection  41  provided on coupling gear  40 . Consequently, the mechanism provides an easy means for controlling the motor and can be inexpensively manufactured.  
         [0046]    Further in this embodiment, toilet cover  6  is driven by stepping motor  60 . When a user manually opens toilet cover  6  during closing motion driven by the motor, stepping motor  60  loses synchronism or does not rotate. This allows the user to handle toilet cover  6  with minimum force even though toilet cover  6  is moved in the reverse direction (upward, opening direction) while the motor is driving the toilet cover  6  in the downward, closing direction.  
         [0047]    Further more, stoppers  31  and  32  are provided as a part of unit casing  30  wherein stoppers  31  and  32  mechanically define the starting position and the ending position of sector gear  50  as sector gear  50  rotates from a fully opened position to an inclined starting position: for example, when a manual opening motion occurs in the middle of the motor driven closing motion and displaces the driving member from the target point that meets the duration of conduction, stopper  31  initializes sector gear  50  to return sector gear  50  to its original position utilizing the reversed spin of the motor. Thus, the motor repeatedly produces an accurate motion all the time as long as its steps or timer is controlled.  
         [0048]    In the above embodiment, sector gear  50  and coupling gear  40  share the same axial center and a switching mechanism  80  is arranged therebetween. However, a switching mechanism may be constructed with a driving member and a slave member having a separate axial center.  
         [0049]    As described above, to close a toilet cover that is kept open by clockwise motion of a motor, the present invention accomplishes the task in the following manner: a driving member connected to the motor end and a slave member connected to the toilet cover at the rotary shaft end are mechanically connected to each other. Therefore, a motor drives the closing motion of the toilet cover. When the toilet cover rotates to an inclined starting position at which the toilet cover&#39;s self-weight initiates the closing motion, a switching mechanism disconnects the mechanical connection between the driving member and the slave member. The slave member, thus, responds to the self-weight initiated rotary motion of the toilet cover independent of the driving member while the driving member returns to its original position where the toilet cover is in a fully opened position independent of the slave member taking advantage of the reversed spin of the motor. For this reason, as a user manually opens a toilet cover, the slave member moves in response to the motion of the toilet cover but the driving member connected to the output shaft end of the motor does not respond to such a motion. The user can thus handle the toilet cover with little force. Moreover, the toilet cover moves in the closing direction as long as the mechanical connection between the driving member and the slave member is released. Consequently, the motor can be controlled easily and the toilet cover opening/closing device can be manufactured cost effectively.  
         [0050]    The foregoing specific embodiments represent just some of the ways of practicing the present invention. Many other embodiments are possible within the spirit of the invention. Accordingly, the scope of the invention is not limited to the foregoing specification, but instead is given by the appended claims along with their full range of equivalents.