Patent Publication Number: US-4729490-A

Title: Automatic touch actuated door opener

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This is a continuation-in-part of U.S. patent application Ser. No. 793,988, filed Nov. 1, 1985; now U.S. Pat. No. 4,609,122. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention is directed generally to an automatic power door opener and more particularly to a touch actuated door opener such that touching pressure against a pivoted door will actuate a power source to move the door to its open position. Even more specifically, the invention is directed to a trash housing of the type wherein the cover over an open topped trash receptacle has a swinging access door connected to a touch actuated door opener. Accordingly, when it is desired to dispose of trash in the receptacle, opening pressure against the door causes the automatic door opener to raise the door to its open position, hold for a predetermined time and then allow it to return to the closed position. 
     In many business establishments and in fast food restaurants in particular, trash receptacles are provided as a housing with a swinging door hinged across the top. It is difficult to dispose of trays of paper cups and food wrappers since the door tends to swing down against the trash preventing it from being easily dumped into the receptacle. It is generally a two-hand operation, one for holding the door open and the other for dumping the trash into the receptacle. A customer carrying a child, briefcase or the like therefore has a very difficult time assisting the establishment by disposing of his trash. 
     Various types of automatic door openers are known but all have certain limitations. A floor mat actuator for a trash housing door would cause the door to be opened even by passersby. A power opener for a trash housing door could alternately be actuated by an infrared light across the front of the door but the beam could be rendered inoperative by food spilled on the sender or receiver. Furthermore, the infrared actuator would likely require some modification of the housing itself and could be actuated by a customer standing close to the receptacle. The same would be true of other types of presence detectors. 
     Regardless of the type of actuator, it is undesirable to provide a mechanical linkage to the door which will render the door inoperative if the power unit fails. It is also important that the door be automatically reopened if it is contacted while being closed. 
     Accordingly, a primary object of the invention is to provide an improved automatic touch actuated door opener. 
     Another object is to provide a touch actuated door opener for the swinging door of a trash housing. 
     Another object is to provide a touch actuated door opener which can be easily installed without altering the outside of a trash housing. 
     Another object is to provide an automatic touch actuated door opener which is usable with virtually any door. 
     Finally, it is an object to provide an automatic touch actuated door opener which is simple and rugged in construction, inexpensive to manufacture and efficient in operation. 
     SUMMARY OF THE INVENTION 
     The automatic touch acuated door opener of the present invention is ideally suited for use in a trash housing for automatically raising the swinging door when it is touched by a hand, food tray or the like. A switch responsive to initial opening movement of the door actuates a power source for swinging the door to its fully open position. A time delay switch associated with the power source allows the door to return to its closed position after a preselected time interval. 
     The automatic door opener preferably includes an elongated flexible tension member having one end adapted for connection to a door and the other end connected to a tension member take-up device mounted in spaced relation from the door so that the door is moved to its open position in response to actuation of the take-up device. Gravity and/or a biasing device urges the door to its closed position thereby to maintain tension in the tension member when the door is moved to its closed positon. A switch in contact with the tension member senses decreased tension due to external pressure against the door and actuates the take-up device to automatically open the door. The above-mentioned time delay switch causes the take-up device to allow the door to return to its closed position after the preselected time interval. It is preferred that adjustable limit switches be incorporated within the door opener for deactivating the power source upon movement of the door to the selected open and closed positions. 
     A simplified door opener includes a pair of limit switches situated adjacent the tension member, both switches being engaged in response to increased tension in the tension member upon operation of the take-up device to open the door. The second limit switch is arranged for release prior the first limit switch in response to decreased tension in the tension member upon return of the door to the closed position. The take-up device is immediately deactuated in response to release of the second limit switch and is reactuated upon release of the first limit switch when opening pressure is again exerted against the door. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view of a fast food restaurant trash container showing a tray contacting the door for actuating the opener; 
     FIG. 2 is an enlarged side-sectional view showing the door opener mechanism and the door in a closed position; 
     FIG. 3 is an enlarged side-sectional view showing the door opener mechanism and the door in the open position thereof; 
     FIG. 4 is a further enlarged detail side view of the door opener mechanism; 
     FIG. 5 is a bottom plan view of the door opener mechanism; 
     FIG. 6 is an electrical diagram for the door opener mechanism; 
     FIG. 7 is a perspective view of an alternate embodiment of the door opener mechanism; 
     FIG. 8 is an enlarged side sectional view of the door opener and the door in a closed position; 
     FIG. 9 is a diagrammatic top view of the door opener showing both limit switches engaged; 
     FIG. 10 is a diagrammatic top view of the door opener showing the second limit switch released; 
     FIG. 11 is a diagrammatic top view of the door opener showing both limit switches released; and 
     FIG. 12 is an electrical circuit diagram for embodiment of FIGS. 7-11. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     In FIG. 1, there is shown a trash housing 10 which includes an open-topped trash receptacle 12 and an attractive matched cover housing 14. The cover housing 14 has a flat top surface 16 for the storage of trays 18. A swinging door 20 is hingedly mounted in a front opening 22 for providing access to the trash receptacle 12. As is described hereinbelow, swinging door 20 will be automatically opened when it is contacted by a food tray 18, as shown in FIG. 1, or by the hand of the customer 24. 
     FIGS. 2 and 3 show that door 20 is hingedly mounted for pivotal movement about an axis 26 adjacent the top of the door. The door 20 is pivotally moveable between the closed position of FIG. 2 and open position of FIG. 3. 
     The automatic door opener 30 of the invention is shown as mounted on the interior side of top wall 16 close to the free end of the door in its open position. Door opener 30 includes an elongated flexible tension member or cable 32 having one end 34 connected to the door 20, preferably adjacent the free end 36 thereof. A cable is trained over an idler pulley 38 and around a take-up pulley 40 which is rotatable by a motor 42 to take up the cable 32 and thereby pivot door 20 upwardly to the open position. A time delay switch described hereinbelow allows the door to return to its closed position at a predetermined time after movement of the door to the open position. Door 20 is biased to its closed position by the gravitational weight of the door. In addition, a torsion spring 44 is mounted on the interior side of top wall 16 adjacent the upper end of swinging door 20. Spring 44 has a depending biasing arm 46 which engages the door and urges it in a pivotal direction toward the closed position of the door. It is apparent that the torsion spring 44 could be replaced by a tension spring, a compression spring and rod mechanism, a door weight or the like for biasing the door to its closed position. 
     Actuation of motor 42 is effective by touching pressure against the front of door 20, as illustrated in FIG. 3. Food tray 18 is shown pressed against the door 20 to swing it slightwardly inwardly. The decreased tension in cable 32 is sensed by the door opener for actuating the motor 42 to automatically raise the door. 
     A preferred configuration for the automatic door opener 30 is shown in FIGS. 4 and 5. The mounting plate 50 is secured by screws 54 and spacers 56 to the cover housing top wall 16. It could alternately be secured to the rear wall or side walls but the illustrated position is preferred for simplicity and balance. 
     The take-up pulley 40 is rotatably sandwiched between the mounting plate 50 and gear transfer case 58. It is preferred that there be practically zero clearance on either side of the pulley to prevent the cable from wrapping around the pulley shaft 60 when tension on the cable is relaxed. Motor 42 is preferably provided as a reversible electric motor to thereby control both the opening and closing movement of the door 20. The gear transfer case 58 drivingly connects the motor to the output shaft 60 which carries the take-up pulley 40 on one side of the transfer case and a primary drive gear 62 for a limit switch mechanism 64 on the other side of the transfer case. 
     Limit switch mechanism 64 is carried within a housing 66 depending from transfer case 58. An externally threaded shaft 68 is rotatably supported between the housing 66 and transfer case 58 at a position with a fixed driven gear 70 in meshed relation with primary drive gear 62. A pair of wheels 72 and 74 are threadably mounted on shaft 68 and each gear is provided with axially directed external gear teeth adapted for engagement by the turned up flange 76 of spring plate 78 for preventing rotation of the wheels except when being adjusted. Accordingly, the wheels 72 are moved axially of shaft 68 in response to rotation of the shaft. A first limit switch 80 is mounted on housing 66 with an actuator arm 82 extended into the path of first wheel 72 such that, upon opening of the swinging door 20, first wheel 72 is moved in an upward vertical direction as shown in FIG. 4. Upon engagement with actuator arm 82, limit switch 80 is tripped to deactivate motor 42. When the motor is reactivated by the time delay switch for lowering the door, the second wheel 74 is caused to move downwardly on shaft 68 to the extent of engagement with the actuating arm 84 of a second limit switch 86 for again deactivating motor 42. As shown in FIG. 5, flange 76 of spring plate 78 may be manually pulled away from the wheels 72 and 74 for threadably adjusting the position of the wheels on the shaft for adjusting the desired stopping positions of the door 20 in its open and closed positions. 
     Initial activation of the automatic door opener 30 is effected by a tension-sensitive switch 88 shown in FIG. 5. between idler pulley 38 and take-up pulley 40. Cable 32 is trained through a roller-less actuator 90 on the end of actuator arm 92. Switch 88 is so positioned that tension in cable 32 forces the actuator arm toward the switch for closing the switch. When pressure is exerted against the front of the swinging door 20, tension in cable 32 is relaxed with the result that the internal biasing force on switch actuator arm 92 causes the tension-sensitive switch 88 to be opened for actuating motor 42. 
     The operation of the automatic door opener 30 will be described in connection with the electrical circuit diagram of FIG. 6. Again, touching pressure against swinging door 20 relaxes tension in cable 32. This is detected by tension-sensitive switch 88 which acts through the printed circuit board 94 to activate motor 42 in a direction to raise swinging door 20. As the door reaches its open position, first wheel 72 of limit switch mechanism 64 strikes the first limit switch 80 to deactivate the motor 42. A potentiometer 96 on circuit board 94 effects a time delay prior to reactivation of motor 42 in the opposite direction for lowering swinging door 20. As the door returns to its closed position, second wheel 74 of limit switch mechanism 64 strikes second switch 86 to again deactivate motor 42. Accordingly, this completes one opening and closing cycle of the automatic door opener 30. 
     If the door is contacted during its closing movement, it is apparent that tension in cable 32 will be relaxed. This will be sensed by switch 88 which causes the automatic door opener 30 to recycle thereby immediately reopening the door and holding it open prior to automatic closing. 
     Power may be supplied from a standard 110 volt wall outlet to a plug in type transformer 98. A one-quarter amp circuit breaker 102 is provided as shown. Transformer 98 directs a 24 volt output through a bridge rectifier 104 for operating motor 42 at increased speed during raising movement of the door, as compared to 12 volt power directed through bridge rectifier 106 for slowing down the motor during closing movement of the door. The slower closing movement is not as surprising to a customer unfamiliar with the device. 
     In the circuit, circuit board 94, which includes relay 108, is commercially available from SSAC Manufacturing Company in New York as part number ORM24A22. Other details of the preferred embodiment relate to the cable 32 which may be provided as a 49 strand stainless steel 3/64 inch cable which is plastic coated to a 1/16th inch outside diameter. It is preferred that the cable be flexible for live action of the tension sensitive switch 88. It is preferred that the sensitivity be such that up to 1/4, and preferably 1/32nd inch movement of the cable in response to pressure on the door will cycle the opener 30. 
     The automatic door opener 30 is compact and could be easily installed on existing trash housings. It is usable on virtually any door and does not require that the outside surface of the trash housing be modified in any way. The swinging door in fact shields the door opener from contact with refuse being placed in the receptacle so as to eliminate any sanitation problems. 
     FIGS. 1, 2 and 3 show that the top edge of the swinging door may be covered by a protective flexible strip 110 and that a quarter-round strip 112 on the back side of the door 20 at the upper edge furthermore prevents the insertion of fingers between the door and top edge of the housing opening for safety. 
     Whereas a preferred embodiment of the invention has been shown and described herein, it is apparent that many modifications, additions and substitutions may be made which are within the intended broad scope of the appended claims. For example, the limit switch mechanism 64 could be replaced by a cog tooth counter for the main drive gear or by other suitable mechanisms. The time delay potentiometer may be replaced by a fixed resistor for a preset preferred 6 second time delay interval. For use on outside trash housings, electrical power may be provided by a gel battery and solar collector. 
     An alternate embodiment of the automatic touch actuated door opener of the invention is illustrated in FIGS. 7-12. In FIG. 7, the door opener mechanism 120 is shown as including a shallow housing 122 which is secured by a mounting plate 124 to the interior surface of top wall 126 of trash receptacle 128. A depending cover 130 encloses the operating components of the mechanism. A power cord 132 extends rearwardly from the housing 122 for insertion into an electrical outlet. A nylon cord or tension member 134 extends forwardly from housing 122 through a slot 136 for connection to an eye bolt 138 secured adjacent to lower interior edge of swinging door 140. The connection to the eye bolt may be by a removable spring clasp 142. In addition, a bumper washer 144 is positioned on cord 134 by a knot 146 for engagement with housing 122 to limit the exent that the cord can be taken up. 
     FIG. 8 shows that housing 122 supports an elongated gear case 148 spaced from the housing top wall 150 sufficiently for rotatably supporting take-up pulley 152 therebetween. The pulley is driven by the motor 154 suspended at the opposite end of gear case 148. Actuation of motor 154 is controlled by electrical circuitry mounted on plate 156 together with first and second limit switches 158 and 160. 
     Tension cord 134 is secured to take-up pulley 152 and is directed past the first and second limit switches 158 and 160 to a simulated pulley block made of a plastic delron material. The block is grooved for positive transverse positioning of cord 134. 
     An important feature of the invention is the strategic placement of the first and second limit switches 158 and 160 for controlling actuation of motor 154 for opening and closing the door. The first limit switch 158 is shown in FIG. 9 in a staggered position slightly closer to cord 134. A single actuator arm 162 on first limit switch 158 extends across the plunger actuators 164 and 166 of both switches and terminates in a bent contact portion in engagement with cord 134. Tension in cord 134 forces actuator arm 162 toward both switches, thereby engaging both switches. Decreased pressure in cord 134 enables the internal biasing force of actuator arm 162 to move away from second limit switch 160 thereby releasing that switch. The second limit switch 160 immediately deactuates motor 154 which thereby acts as a dynamic break to stop the take-up pulley 152 and prevent further loosening of cable 134. When tension is further decreased by initial opening movement of swinging door 140, first limit switch 158 is released thereby actuating motor 154 to again open the door. 
     The operation of the improved automatic door opener mechanism 120 will be described with references to the electrical circuit diagram of FIG. 12 and to the diagrammatic illustrations of the limit switches in FIGS. 9-11. The door is opened by pushing on the swinging door 140. This loosens the nylon lift cord 134 and releases first limit switch 158. That switch acts through printed circuit board 168 to begin the timer and start motor 154 winding up cord 134 and opening the door 140. The motor continues to reel in cord 134 until bumper washer 144 strikes housing 122 and the motor stalls out for the balance of approximately 5-6 seconds. After timing out, a relay 170 drops out and reverses motor 154. Both limit switches 158 and 160 have been engaged since the opening first started due to the increased tension in cord 134. Upon reversing, both limit switches 158 and 160 remain engaged. The door lowers slower than it was raised and when the door reaches a near vertical position by gravity, it will stop, closed. This means cord 134 is still loosening for a split second until the second limit switch 160 is released and this stops motor 154. Another push on door 140 will start the cycle all over again. 
     Also, the door 140 can stop anywhere on the way down, upon striking trash, an inserted tray or any other obstacle, and it will not reverse or open. It will just sit there until it is pushed again to restart the cycle. Because of this and the lack of any adjustments to be made, this embodiment is self-adjusting. It eliminates a lot of parts and is smaller than the previous embodiment. The quick-attach mounting bracket 124 makes installation quicker. It is preferred that the unit be sealed so customers cannot tamper with the insides. 
     The circuit diagram of FIG. 12 shows that power may be supplied either through an AC transformer 172 or a DC battery pack 174. Other detailed specifications of the electrical circuitry are indicated below. 
     
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B1 RB152 Bridge                                                           
               C6 100 MFD, 50 VDC                                         
D1 IN4002      R6 1.3K ohm                                                
Cl 470 MFD, 63 VDC                                                        
               R7 2.7K ohm                                                
R1 4.7K        R8 51K ohm                                                 
C2 33 MFD, 35 VDC                                                         
               R9 100K ohm                                                
C3 .1 MFD, 50 V                                                           
               D4 IN4002                                                  
D2 IN4744A, 15 V 1 W                                                      
               Relay 170 P&amp;B T82P11D111-24 V                              
R2 56K ohm     R10 56K ohm                                                
R3 7.5 Meg. ohm                                                           
               C7 1.5 MFD, 80 V                                           
C4 1.0 MFD, 50 V                                                          
               R11 10 Meg. ohm                                            
R4 560K ohm    D5 IN4002                                                  
C5 1.0 MFD, 50 V                                                          
               D6 IN4737A, 25 V, 1 W                                      
IC1 MC14538    R12 10 Meg Ohm                                             
D3 IN4002      R13 2.7K ohm, 1/2 W                                        
IC2 LM 317 T   Motor 154 24 VDC                                           
R5 1.0 ohm                                                                
C6 100 MFD, 50 VDC                                                        
R6 1.3K ohm                                                               
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     Thus there has been shown and described an automatic touch actuated door opener which accomplishes at least all of the stated objects.