Abstract:
A clutch assembly is provided for coupling a drive shaft with a drive arm of an actuator for use with an automatic toilet flushing system, wherein the drive shaft is adapted for rotation via a motor in the actuator. The clutch assembly includes a rotatable body extending between the drive shaft and the drive aim and having a first engaging member. A clutch disk is secured to the drive shaft and includes a second engaging member adapted for cooperating with the first engaging member of the body. A fastener secures the clutch disk to the drive shaft and a biasing member is provided for biasing the body toward the clutch disk. The body is adapted to overcome the biasing force of the biasing member should a predetermined torque on the drive shaft be exceeded to disengage the first and second engaging members and prevent damage to the drive shaft.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is based on Provisional Patent Application No. 60/932,545, filed May 31, 2007, entitled “Actuator Having a Clutch”, on which priority of this patent application is based, and which is hereby incorporated by reference in its entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to automatic toilet flushing systems and, more particularly, to an automatic actuator having a clutch assembly for flushing toilets, such as home toilets or other toilets found in private dwellings or facilities. 
     2. Description of Related Art 
     There are many commercially available automatic toilet flushing systems for use in various commercial and industrial establishments. Also, automatic toilet flushing systems for use in conventional home toilets or other toilets found in private dwellings have been disclosed, for example, in U.S. Pat. Nos. 4,141,091 to Pulvari; 5,003,643 to Chung; and 6,202,227 to Gurowitz. These prior art automatic flushing systems for conventional toilet flushing systems are desirable for a variety of reasons, for example, sanitary considerations by one not having to touch a handle used by others. Also, people suffering from temporary or permanent disabilities may find it difficult to access a toilet flush handle, which is usually located rearwardly of the toilet seat. In other cases, forgetfulness or non-attentiveness of individuals may prevent them from manually flushing the toilet. In these and other situations, an automatic toilet flushing system for private dwelling structures may provide a significant advantage. 
     In the prior art automatic toilet flushing systems, converting a conventional toilet to one capable of automatic flushing after use can oftentimes be difficult and relatively expensive, such as requiring new or substituted toilet fixtures. Automatic flushing systems include an automatic actuator that is coupled with a flapper valve to release water from the reservoir tank upon receipt of a flushing signal. Occasionally, these flapper valves can get caught on something and fail to open, causing the application of excessive torque to the actuator motor. This can result in the motor becoming overheated. Therefore, there is a need to provide an automatic toilet flushing system that is easy to install on conventional toilets while using the existing toilet fixtures, including the existing toilet components, for example, the toilet bowl and reservoir tank for holding water that may constitute a conventional or standard toilet. There is a further need to provide a device capable of avoiding the application of this excessive torque to the actuator motor. 
     SUMMARY OF THE INVENTION 
     The present invention has met these needs. More particularly, the invention provides an automatic toilet flushing system for a toilet having a reservoir tank and a toilet bowl. The system includes a sensor for sensing the approach and departure motion of a user with respect to the toilet and for generating a signal representative of the approach and departure motion of the user; an actuator in communication with the sensor for causing an automatic flushing of the toilet in response to the signal from the sensor, wherein the actuator includes a drive shaft coupled to a drive arm via a clutch assembly; and a flushing mechanism co-acting with the actuator. The flushing mechanism includes a flapper valve connected to the drive arm, wherein the flapper valve is adapted to release water from the reservoir tank upon actuation of the toilet flushing system. 
     In an embodiment of the invention, the actuator is a mechanical actuator and has a gear train, a motor with an output shaft rotatably connected to the gear train, a pivotal arm having a drive shaft rotatably connected to the gear train, and a power source for activating the motor and rotating the output shaft of the motor which, in turn, rotates the gear train for pivotal movement of the drive shaft of the pivotal arm, and, therefore, pivotal movement of the pivotal arm. The flushing mechanism includes a flapper valve for releasing water out of the reservoir tank and into the toilet bowl, and the drive arm of the pivotal arm is connected to the flapper valve for operation of the flapper valve upon the pivotal movement of the drive shaft connected to the pivotal arm. 
     The actuator box has an opening in the sidewall of the second compartment, and the shaft connected to the pivotal arm of the actuator extends through the opening in the sidewall of the second compartment for supporting the pivotal arm outside of the actuator box. The pivotal arm may be connected to the flapper valve via a handle swivel connected at the end of the pivotal arm and a connector member, e.g., a chain attached to the handle swivel and the flapper valve or via a tab connected at the end of the pivotal arm and a connector member, e.g., a chain attached to the tab and to the flapper valve. 
     The sensor senses the approach and departure motion of a user with respect to the toilet and, in an embodiment of the invention, includes a housing having a body that defines a first section and a second section. The first section has a first closed end, a second open end, and first and second openings. The first opening has a signal generating source for transmitting a signal, and the second opening has a signal detector for receiving the transmitted signal from the signal generating source in the first opening, thereby detecting the presence of a user of the toilet. 
     According to a further embodiment of the invention, a clutch assembly is provided for coupling a drive shaft with a drive arm of an actuator for use with an automatic toilet flushing system. The drive shaft is adapted for rotation via a motor in the actuator. The clutch assembly includes a rotatable body extending between the drive shaft and the drive arm. The body includes a male member extending in an outward direction with respect to the body. A clutch disk is secured to the drive shaft. This clutch disk includes a female member adapted for cooperating with the male member of the body. A fastening member is provided for securing the clutch disk to the drive shaft. The fastening member includes a head positioned a predetermined distance from the body and a biasing member is caged between this head and the clutch disk. The body is adapted to overcome this biasing force should a predetermined torque on the drive shaft be exceeded to disengage the male member of the body from the female member of the clutch disk and prevent damage to the actuator motor. 
     It is therefore an object of the invention to provide a clutch assembly coupled to an actuator for an automatic toilet flushing system wherein the clutch assembly is capable of disengaging the actuator from a drive arm of the flushing mechanism should a predetermined torque applied to this drive arm be exceeded to prevent damage to the motor of the actuator. 
     These and other objects and advantages of the present invention will be better appreciated and understood by those skilled in the art from the following description and appended claims. It is to be understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of the actuator having a clutch connected to the flapper valve installed in the reservoir tank in accordance with the present invention and showing a sensor arrangement according to a first design; 
         FIG. 2  is a top perspective view of an actuator housed in an actuator box installed in a reservoir tank for an automatic toilet flushing system made in accordance with the present invention and showing a sensor arrangement according to a second design; 
         FIG. 3A  is a perspective view of the actuator with the battery tray exposed and the sensors to which the actuator can be electrically coupled; 
         FIG. 3B  is an exploded front perspective view of an actuator shown in  FIGS. 1 and 2 ; 
         FIG. 3C  is a rear perspective view of an actuator box shown in  FIG. 3B ; 
         FIG. 4A  is an exploded view of the external rotating arm having a clutch for the actuator including an engaging member according to a first embodiment in accordance with the present invention including a series of bevel washers acting as a biasing member; 
         FIG. 4B  is a view of the rotating arm and clutch of  FIG. 4A  in an engaged position; 
         FIG. 4C  is a rear view of the rotating arm of  FIG. 4A ; 
         FIG. 5A  is an exposed view of the external rotating arm having a clutch for the actuator including an engaging member according to a second embodiment in accordance with the present invention; 
         FIG. 5B  is a view of the rotating arm and clutch of  FIG. 5A  in an engaged position; 
         FIG. 5C  is a rear view of the rotating arm of  FIG. 5A ; and 
         FIG. 6  is an exploded view of the external rotating arm having a clutch for the actuator in accordance with the present invention including a spring acting as a biasing member. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS. 1 and 2 , the invention provides an automatic toilet flushing system  10 ,  60  for a conventional toilet  45 , which has a toilet bowl  46  and a reservoir tank  13 . The automatic toilet flushing system  10  includes an actuator  12  mounted in the reservoir tank  13  via a bracket  47  and in communication with a sensor  14 , which is mounted into a sidewall of the conventional toilet  45 . The sensor  14  may be in communication with the actuator  12  via a wire  48  or via a transmitted signal (i.e., wireless communication). In the wireless communication arrangement, a radio frequency transmitter can be provided in the sensor  14  and a corresponding radio frequency receiver may be provided in the actuator  12 . Referring to  FIG. 3B , the actuator  12  is housed in an actuator box  16  and includes a gear train  18 , a motor  20  having an output shaft  22 , and an external rotating arm  24  having a shaft  26 . The output shaft  22  of the motor  20  is rotatably connected to the gear train  18 , and the external arm  24  is rotatably connected to the gear train  18  via shaft  26 . A power source, such as a battery  28 , is electrically connected to the motor  20 . For wireless communication, a signal transmission receiver (not shown) in communication with both the sensor  14  and the motor  20  may be used to receive transmitted signals from the sensor  14 , thus activating and/or deactivating the motor  20 . It is conceivable that the power could be provided via an electric line from an external power source coupled directly to the battery  28 . 
       FIGS. 3A-3C  show the actuator box  16  of the automatic flushing system  10  having an open end  17  defining a first compartment  32  and a second compartment  34 . As shown in  FIG. 3B , the first compartment  32  of the actuator box  16  can be used to house the battery  28  and a signal transmission receiver for wireless communication (not shown), and the second compartment  34  can be used to house the gear train  18  and the motor  20 . Referring to  FIGS. 3B and 3C , the open end  17  of the first compartment  32  of the actuator box  16  defines a plurality of holes  33  adapted to receive fasteners. The actuator box  16  is preferably made of a unitary piece of molded plastic so as to be resistant to water and chemicals normally present in a toilet/bathroom environment. 
     Referring particularly to  FIG. 3B , the external arm  24  is pivotably mounted on the outside of the actuator box  16 , wherein the shaft  26  of the external arm  24  extends through an opening  51  in a sidewall of the actuator box  16 , thus connecting the external arm  24  to the gear train  18 . When the motor  20  is activated, the output shaft  22  of the motor  20  rotates the gear train  18 , thereby pivotably rotating the external arm  24 . 
     Referring again to  FIG. 3B , a first cover  36  having a body  38  and defining a plurality of slots  39  is used to cover the first compartment  32  of the actuator box  16 . The first cover  36  can be attached to the open end  17  of the first compartment  32  of the actuator box  16  via a fastener (not shown) passing through slot  39  defined in the cover body  38  of cover  36  and hole  33  defined in the actuator box  16 . 
     Still referring to  FIG. 3B , a second cover  40  having a body  42  may be used to cover the second compartment  34  of the actuator box  16 . The second cover  40  is preferably sealed to the open end  17  of the second compartment  34  of the actuator box  16  by sonic welding. A gasket, such as an O-ring (not shown), can be inserted between the covers  36 ,  40  and the open end  17  of the actuator box  16  to seal the compartments  32 ,  34 , thus preventing moisture from entering. 
     Still referring to  FIG. 3B , the gear train  18  is used to rotate the external arm  24  of the actuator  12 . The external arm  24  includes a body  25 , wherein the shaft  26  is defined at one end of the body  25  and extends therefrom, and a tab  27  is defined at an opposite end of the body  25  and extends in a direction opposite that of the shaft  26 . The shaft  26  of the body  25  of the external arm  24  is keyed to the gear train  18 , and the tab  27  of the body  25  of the external arm  24  is connected to a flapper valve  76  via a bead chain  49  as particularly shown in  FIG. 1 . A handle swivel  50  co-acting with the tab  27  can also be used to connect the external arm  24  to the flapper valve  76 . This handle swivel  50  is rotatably coupled to shaft  30  so that it may swivel about a longitudinal axis passing through shaft  30 . The handle swivel  50  has a guide (not shown) that is received in a recess on shaft  30  to hold the handle swivel  50  in place and permit it to rotate. A sealing arrangement  29  is defined between the shaft  26  and the body  25  of the external arm  24  in order to pivotably attach the external arm  24  to the actuator box  16 . A gasket, such as an O-ring (not shown) or cup seal  52 , may be used to seal the opening in the actuator box  16  around the shaft  26  of the external arm  24 , thus preventing moisture from entering the actuator box  16 . A clip  31 , such as an E-clip defined in the second compartment  34 , may also be used to secure the external arm  24  to the outside of the actuator box  16 . 
     Still referring to  FIG. 3B , the actuator  12  includes a battery tray  78  which supports several batteries  28  in first compartment  32 . The batteries  28  may be disposable or rechargeable. The first cover  36  of the first compartment  32  includes a thumb screw  53  used in conjunction with a gasket (not shown) to seal the first compartment  32 . A stabilizing arrangement, such as the use of a clip, screw and knurled insert represented by elements  54  and  55 , can be used to further secure the actuator  12  to the tank reservoir  13  as shown in  FIGS. 3B and 3C . Such an arrangement is disclosed in U.S. patent application Ser. No. 11/789,034, which is hereby incorporated by reference. 
     The sensor  14  of the automatic flushing system  10  detects when a human body comes within a predetermined distance with respect to a toilet bowl (not shown). The sensor  14  can be mounted on a wall in close proximity to actuator  12 , such as shown in the design of  FIG. 1 , or it can be located in the manual flush handle hole of a conventional toilet, thus replacing the manual flush handle as shown according to the design of  FIG. 2 . However, the sensor  14  can be located anywhere in the bathroom as long as it can detect a person approaching the toilet. The sensor  14  preferably uses ultrasound technology to detect a user near the toilet. By using ultrasound technology, false detection due to moisture, such as steam, is eliminated. Also, ultrasound technology is not sensitive to color and can operate in all shades of light. The sensor  14  can also utilize magnetic, electrostatic, optical, and electromagnetic principles for detection of a person in the vicinity of the sensor  14 . Other types of sensors may be used, such as heat sensors and infrared sensors. 
     As shown in  FIG. 2 , the sensor  14  includes a housing  58 , which is preferably made of a material that is resistant to chemicals and water, such as a polymeric material. A plurality of openings  62 ,  62 ′ are provided wherein the ultrasound generating source (not shown) can transmit ultrasound waves passing through the opening  62 , and an ultrasound detector (not shown) can receive ultrasound transmissions passing through opening  62 ′, thus detecting a user at the toilet. Alternatively, openings  62  and  62 ′ can be an infrared transmitter and receiver, respectively. Infrared transmitters and receivers are well-known in the art. 
     Referring to  FIG. 2 , the sensor  14  can be mounted into the flush handle hole of the toilet  45 , via a nut  56  threadably fastened to a threaded portion of the member  64 . The sensor  14  is electrically connected to the motor  20  in the actuator box  16  via the wire  48  passing through the center passageway  66  of the member  64  and sandwiched between the first cover  36  and actuator box  16 , as shown in  FIG. 1 . The wire  48  should be thin enough to allow the first cover  36  to seal properly, thus preventing moisture from entering the actuator box  16 . However, grommets or other types of seals or sealants can be used for the wire  48  to pass through the actuator box  16 . 
     An alternative design for an automatic toilet flushing system  60  is shown in  FIGS. 1 and 3A . In this design, the sensor  14  can have a rectangular design  68 , or a round design  72  having a housing  69 ,  73  that is mounted on a wall in close proximity to actuator  12 . The housing  69 ,  73  includes a sensor element  70 ,  74 . The sensor element  70 ,  74  can be an infrared sensor that is well-known in the art to detect the presence of a user. The sensor housing  69 ,  73  is preferably mounted on a wall in close proximity to actuator  12 . However, it can be appreciated that sensor housing  69 ,  73  may be located anywhere in the bathroom as long as it can detect a user near the toilet. The sensor housing  69 ,  73  can house all of the internal components of sensor  14 , including a transmitter for wireless communication (not shown), thereby eliminating the need for a physical connection, such as a wire  48  between the sensor  14  and the actuator  12 . For wireless communication, the transmitter can transmit a signal from the sensor element  70 ,  74  to a signal transmission receiver (not shown) in the actuator box  16 , for example, by radio frequency transmissions. The sensor housing  69 ,  73  can be attached to a wall or an object using mechanical fasteners, adhesive tape or other means known in the art. The wire  48  can use female/male connector  85 ,  86  to attach the sensor  14  to the actuator  12 . 
     In a conventional toilet  45 , with which the automatic flushing system  10  and  60  may be used, the toilet  45  comprises a toilet bowl  46  and a reservoir tank  13  (also referred to as a water chest) located immediately rearwardly of and above the toilet bowl  46 , as best shown in  FIG. 2 . In this way, water is allowed to drain from the reservoir tank ( 13  by the force of gravity directly into the toilet bowl  46  through conventional plumbing connections. Referring particularly to  FIGS. 1 and 2 , the toilet is generally provided with the flush handle normally located on the side of the reservoir tank  13  and which operates a flushing mechanism  57  located within the reservoir tank  13 . This flushing mechanism  57  typically includes the flapper valve  76  which is located at the lower end of the reservoir tank  13  and which can be opened and closed with respect to a water outlet  88  covered by the flapper valve  76  for releasing water into the toilet bowl  46 . Referring to  FIGS. 1 and 2 , the actuator  12  is mounted to a ledge of the reservoir tank  13  via the bracket  47 , and the chain  49  connects the actuator  12  to the flapper valve  76  (shown best in  FIG. 1 ). One end of the chain  49  is connected to the handle swivel  50  on the external arm  24  and the opposite end of the chain  49  is connected to the flapper valve  76 . 
     In operation, the sensor  14  transmits a signal, such as ultrasound waves or infrared signals, through opening  62  of the sensor housing  58  within a vicinity of a toilet area. When a person comes within range of the toilet  45 , the signal is reflected by the body of the person and a receiver (not shown), such as an ultrasound receiver or infrared receiver, will receive a modulated signal through opening  62 ′, thus detecting the presence of the person. The sensor  14  relays this signal to the actuator  12  via wire  48  or via wireless transmissions, such as radio frequency transmissions. A delay circuit which delays the signal for a predetermined time can be used to ensure that there is a person using the toilet  45 , and not just passing by. When the person finishes and leaves the toilet area, a modulated signal is not received by the receiver, thus indicating that no person is present. When this occurs, the motor  20  is activated and rotates the gear train  18 , the rotation of which will rotate shaft  26  of rotating arm  24 . 
       FIGS. 1 ,  3 A,  3 B,  4 A,  4 B,  5 A and  5 B show the clutch feature for use with the actuator  12  made in accordance with the present invention.  FIG. 1  shows the actuator  12  as installed in the reservoir tank  13 .  FIG. 3A  shows the actuator  12  with the battery tray  78  exposed and with the round sensor  72  and the rectangular sensor  68 . Both the round sensor  72  and the rectangular sensor  68  can be electrically coupled to the actuator  12  by connecting the respective female member  85  to the male member  86  of the actuator  12 . 
       FIG. 4A  shows an exploded view of the external arm  24  used for lifting the flapper valve  76  to drain the reservoir tank  13  shown in  FIG. 1 . The arm  24  contains the clutch feature of the invention to be described below. The arm  24  contains a rotatable body  25 , which includes a first engaging member, which may be a male member  94 , as shown more clearly in  FIG. 4C . Attached to the body  25  is the tab  27  and shaft  30  to which the handle swivel  50  can be attached. The arm  24  rotates one revolution, or 360 degrees, to lift and then lower flapper  76 . The male member  94  on the body  25  is received by a second engaging member, which may be a female member  95  located on a clutch disk  99 , as shown in  FIG. 4B . The clutch disk  99  is connected to a drive shaft  26 , which is driven by the motor  20 . The body  25  is connected to the clutch disk  99  by a fastener  96 , such that a head  97  of the fastener  96  is spaced from the body  25  by a biasing member, such as a series of three bevel washers  98 . The bevel washers  98  have spring-like properties and are positioned to co-act with the body  25  and the clutch disk  99  to bias the body  25  towards the clutch disk  99 . Preferably, the bevel washers  98  are positioned or caged between the body  25  and the clutch disk  99 . A spring  100 , as shown in  FIG. 6 , may be used in lieu of the bevel washers  98 . The biasing member may alternatively comprise a rubber washer or any other well-known member having spring-like properties capable of applying a biasing force to the body  25 . 
     As shown in  FIGS. 5A-5C , an alternative design shows the first engaging member on body  25  as a female member  104  and the second engaging member on the clutch disk  99  as a male member  105 . 
     Referring to  FIG. 1 , in the event that the flapper valve  76  should become stuck or otherwise unable to be pulled open by the chain  49 , the drive shaft  26  could become damaged or the motor  20  could burn out due to the excessive torque. The external arm  24  prevents such damage from occurring. During normal operation, the first engaging member  94 ,  104  of the body  25  remains engaged with the second engaging member  95 ,  105  of the clutch disk  99 . As the drive shaft  26  begins to rotate through its 360 degree cycle, the chain  49  is pulled by the tab  27  or handle swivel  50  attached to the body  25  of the arm  24 . During the first 180 degrees of the rotation of drive shaft  26 , the chain  49  lifts the flapper valve  76  allowing the reservoir tank  13  to be drained. Up on completion of the rotation, the flapper valve  76  is closed. 
     In the event that the torque from the motor exceeds a fixed torque, such as 2.5 inch pounds, the first engaging member  94 ,  104  disengages from the second engaging member  95 ,  105  by compressing the biasing member such as in the form of bevel washers  98 , as shown in  FIG. 4A , or a spring  100 , as shown in  FIG. 6 . In this manner, the torque cannot reach a failure mode, such as the 7.5 inch pound limit at which there is a risk of damage to the drive shaft  26  or motor  20 . The body  25  continues to slip along the clutch disk  99  until the 360 degree rotation of the drive shaft  26  is complete. At this point, the first engaging member  94 ,  104  and second engaging member  95 ,  105  re-engage with the biasing force of the biasing member  98 ,  100 . The external arm  24  is then ready to resume normal operation. 
     It will be readily appreciated by those skilled in the art that modifications may be made to the invention without departing from the concepts disclosed in the foregoing description. Accordingly, the particular embodiments described in detail herein are illustrative only and are not limiting to the scope of the invention, which is to be given the full breadth of the appended claims and any and all equivalents thereof.