Patent Publication Number: US-6711857-B1

Title: Infant safety gate with remote latch activating mechanism

Description:
The present invention is directed to infant safety gates, and more particularly, to infant security gates having a remote latch activating mechanism. 
     BACKGROUND OF THE INVENTION 
     Infant safety gates are widely used to prevent children, particularly infants, from entering a desired area such as a stairwell, or from leaving a desired area such as a playroom or nursery. The gate typically is adjustable between a closed position, wherein the gate blocks the opening and prevents access through the opening, and an open position wherein the gate does not block the opening. In some designs, the gate is attached at one end to a wall or doorway by hinges so that it can swing open or closed. Such gates also include a mechanism at an opposite end to latch the gate in the closed position. 
     The latch mechanisms for such gates are preferably secure and robust to ensure that the latch mechanism is not accidentally activated, or activated by the infant. Existing latch mechanisms are configured to require a relatively high activation force or complex manual manipulation in order to address this issue. Furthermore, existing latch mechanisms are typically located on the gates themselves, and therefore may located at a relatively low height which may be difficult for an adult to access. 
     Accordingly, there is a need for an infant safety gate having a latch activating mechanism which is relatively easy to access and operate by an adult, but difficult to be accessed by a child. 
     SUMMARY OF THE INVENTION 
     The present invention is an infant safety gate having a latch mechanism which is convenient for an adult to access and operate. The invention includes a latch mechanism which can be activated from a location remote from the gate structure by the touch of a button. The button can be positioned to be out of the reach of an infant but easily accessed and operated by an adult. 
     In a preferred embodiment, the invention is an infant safety gate having a remote latch activation mechanism which includes a gate member shaped to be pivotably mounted to a wall and being movable between an open position and a closed position. The latch activation mechanism includes a latch that is adjustable between a locked position, wherein pivotal movement of the gate member is prevented, and an unlocked position wherein pivotal movement of the gate member is permitted. The latch activation mechanism also includes an actuator for switching the latch to the unlocked position. The actuator preferably is located in a position which is inaccessible to an infant whose movement is to be limited by the gate. 
     Accordingly, it is an object of the present invention to provide an infant security gate having a latch mechanism which can be remotely activated easily by an adult, while being inaccessible by the child to be restrained by the gate. It is a further object of the present invention to provide an infant security gate having a latch mechanism that securely locks the gate in place. Other objects and advantages of the present invention will be apparent from the following description, the accompanying drawings and the appended claims. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a perspective view illustrating a preferred embodiment of the infant safety gate of the present invention; 
     FIG. 1A is a schematic representation of a circuit used with the actuator of the present invention; 
     FIG. 1B is a schematic representation of a circuit used with the receiver of the present invention; 
     FIG. 2 is a perspective view of a detail of the gate shown in FIG. 1, showing one embodiment of the latch mechanism; and 
     FIGS. 3-10 are front elevational views of the latch mechanism of FIG. 2, illustrating a sequence of operations to unlatch and latch the latch mechanism. 
    
    
     DETAILED DESCRIPTION 
     As shown in FIG. 1, the present invention, generally designated  10 , is an infant safety gate having a gate member  12  with a pivot side  14  and latch side  16 . The gate  10  is shown mounted to a doorway  18  located between opposing wall portions  20  and  22  of the doorway. However, the gate  10  can to be mounted to a variety of openings besides the doorway  18  shown herein, such as an opening to a stairwell, without departing from the scope of the invention. The pivot side  14  of the gate member  12  is pivotally mounted to the wall portion  20  by hinges  23 . The gate  10  is shown in its closed position wherein the latch side  16  of the gate member  12  is located adjacent to the wall portion  22 . When latched in the closed position, the gate  10  prevents an infant  24  from passing through the doorway  18 . In the preferred embodiment, the gate member  12  includes gate panels  25 ,  26  which are slidably connected to each other by brackets  27 . Consequently, gate member  12  can be adjusted in length to fit doorway  18  by slidably adjusting gate panels  25 ,  26  relative to each other. 
     The gate  10  includes a pair of latch mechanisms  28 ,  29  that selectively attach the latch side  16  of the gate member  12  to the wall portion  22  to lock the gate  10  in a closed position. Latch mechanisms  28 ,  29  are located in a generally vertically-extending housing  30  coupled to the latch side  16  of the gate member  12 . Each latch mechanism  28 ,  29  is actuatable between a locked position, wherein pivotal movement of the gate member  12  is prevented, and an unlocked position, wherein pivotal movement of the gate member is permitted. 
     As will be explained in detail, each latch mechanism  28 ,  29  is remotely actuated by an actuator  32  that is positioned away from the latch mechanisms and gate member. The actuator  32  preferably is located at a position generally inaccessible to the infant  24 , such as on the wall portion  22  or other surface at a height beyond the reach of the infant. The actuator  32  may also be located at a lower position, provided that it is located in an area not accessible to the infant  24 . Each latch mechanism  28 ,  29  includes a receiver  35  that receives a signal sent by the actuator  34 . 
     FIG. 1A illustrates a preferred circuit used with the actuator  34  to control operation of the gate. The circuit includes a switch  80  which is associated with an input of a micro controller  82 . The micro controller  82  includes an output connected through a resistor  84  to control the on/off state of a transistor  86 . A resistor  88  and infrared emitter  90  are connected in line with the transistor  86 . A Panasonic model LN66A infrared emitter may be used as the emitter  90 . A resistor  91  and LED  93 , which can emit visible light, are also connected to the micro controller  82 . 
     When the switch  80  is open, the micro controller  82  maintains the transistor  86  in its off position so that the infrared emitter  90  does not emit any infrared signals. The micro controller  82  also maintains LED  93  in its off position so that the LED  93  does not emit any visible light when the switch  80  is open. When the switch  80  is closed (i.e., by pressing button  34 ), the micro controller  82  turns on the LED  93  and also switches transistor  86  on in a pulsed manner to produce a code infrared signal. The infrared signal is preferably an 8 bit code modulated at 30 Khz, and each code bit is 1 ms in duration. A digital  1  code bit is preferably transmitted as a 0.5 ms modulated pulse followed by a 0.5 ms delay. A digital  0  code bit is preferably transmitted as a 0.5 ms gap (no signal) followed by a 0.5 ms delay, which is the same as a 1.0 ms delay. After the full eight bits have been transmitted there is a delay of 30 ms. If the switch  80  is still closed after the 30 ms delay, the micro controller  82  transmits the 8 bit code again. 
     FIG. 1B illustrates a preferred circuit for use with a receiver  35  of a latch mechanism  28 ,  29 . The circuit includes a green LED  92  and a red LED  94  connected in line with respective resistors  96  and  98 . A micro controller  102  controls the on/off state of the LEDs  92 ,  94 . The on/off state of the infrared detector  100  is controlled by the presence or absence of an infrared signal. The infrared detector  100  is preferably a Siemens model SFH 5110-30 infrared detector. When no infrared signal is detected, the detector  100  remains off. When an infrared signal is received, the detector  100  is turned on and an input to the micro controller  102  is pulled low. The micro controller  102  interprets the low input as a digital  1  coded bit. When the leading edge of such a digital  1  coded bit is received, the micro controller  102  delays for 250 μs to center on the code pulse. The micro controller  102  then observes the state of infrared detector  100  to test each bit for the correct  0  or  1  state according to an acceptable code stored therein and to check for the appropriate off state during each 0.5 ms delay. If the correct 8 bit sequence is observed by the micro controller  102 , a two-second duration high voltage is applied to the gate of transistor  106  through resistor  108  to energize the gate solenoid, which is connected in line with transistor  106 . The transistor  106  is turned on at full, constant voltage for 0.25 seconds to provide sufficient force to activate the solenoid  72 . For the remaining 1.75 seconds, a 33% PWM voltage is applied to the gate of transistor  106 . At the same time that the solenoid  72  is energized, green LED  92  is also turned on to indicate that the gate can be opened. If an incorrect code bit or other error is detected by the micro controller  102 , the solenoid  72  is not activated. 
     The circuit of FIG. 1B also includes low battery power detection provided by the voltage divider formed by resistors  110  and  112  which are arranged to turn off transistor  114  when the battery power falls below a certain level. The micro controller  102  monitors the voltage across resistor  116  which is high when transistor  114  is on, and is low when transistor  114  is off. When the voltage across  116  drops, the micro controller  102  turns on the red LED  94  to indicate that the battery should be replaced. 
     Both micro controllers  82  and  102  preferably include associated dip switches which allow the user to set the desired 8 bit digital code. Of course, in operation the infrared emitter  90  should be positioned to direct its IR signal toward the IR detector  100 . It should be understood that the circuits described and shown herein are only one mechanism for controlling operation of the gate, and other methods or layouts of circuits, or software or other controllers may be used without departing from the scope of the invention. 
     FIGS. 2-10 illustrate, in greater detail, one latch mechanism  28  which may be used in conjunction with the present invention. However, it is to be understood that the latch mechanism illustrated in FIGS. 2-10 and described herein is only one latch mechanism that may be used with the present invention. It should be further understood that a variety of gates, actuators and other hardware beyond the gates, actuators and hardware specifically described and shown herein may be used without departing from the scope of the present invention. 
     The latch mechanism  28  selectively latches the gate  10  to the wall portion  22 . As shown in FIG. 2, the latch mechanism or latch  28  includes a protruding portion, or pin  42 , coupled to the wall portion  22 , and also includes a receiving portion, or cam  44 , located on the gate  10 . The cam  44  is pivotably mounted about a center rod  46 , and includes a generally “U”-shaped slot  48  shaped to receive the pin  42  therein. The rotatable cam  44  includes a generally circular portion  50  having an outer face  52 , the outer face  52  including a notch  54  located opposite the slot  48 . The generally circular portion  50  is not precisely circular in top view, but includes a pair of radially outwardly protruding lobes  56 ,  58  on either side of the notch. The protrusion of the lobes  56 ,  58  in the illustrated embodiment is slight, and may not be visible in the drawings. 
     The latch mechanism  28  further includes a locking arm  60  that is movable into and out of engagement with the rotatable cam  44  to selectively block rotation of the cam. The locking arm  60  is movable in a radial direction relative to the circular portion  50  of the cam. The locking arm  60  includes a pair of legs  62 ,  64  arranged in a generally “V” shape, and a blocking rod  66  is received between the legs. The locking arm  60  is pivotably coupled to a piston  68  by a connecting pin  70 , and the locking arm is free to pivot about the connecting pin. However, the blocking rod  66  limits the pivotal movement of the locking arm  60  about the connecting pin  70 . 
     The locking arm  60  is coupled to the piston  68  of a solenoid  72 , and the solenoid is in turn operatively coupled to the receiver  35 . Thus, the solenoid  72  controls movement of the locking arm  60  into and out of engagement with the rotatable cam  44 . A spring  74  is located between the end of the piston  68  and a plate  76  mounted onto the solenoid  72  to spring bias the locking arm  60  into engagement with the rotatable cam  44 . As noted earlier, the solenoid  72 , locking arm  60  and cam  44  are all received in the housing  30  of the gate. 
     When an adult  36  wishes to open the gate  10 , the adult actuates the actuator  32  by pressing the button  34 , which causes the transmitter  90  to emit a signal. The signal is received by the infrared detectors  100  of the receivers  35  of each latch mechanism  28 ,  29 , which then trigger the respective solenoid  72  of each latch mechanism. Each solenoid  72  then causes its associated latch mechanism  28 ,  29  to move to its unlatched or unlocked position. The adult  36  may then pivot the gate  10  to its open position and walk through the gate, and the gate is then returned to its closed position. The gate  10  may be biased to return to its closed position, or alternately, the adult  36  may manually return the gate to its closed position. The latch mechanisms  28 ,  29  are then activated to switch to their locked positions, thereby locking the gate  10  in its closed position. 
     The latch mechanisms  28 ,  29  may each include a timer such that the latch mechanisms return to their locked positions after a predetermined period of time after the button  34  is activated, such as between 3-10 seconds. However, various other methods or mechanisms for returning the latch mechanisms  28 ,  29  to their locked position, besides the use of a timer, may be used. For example, the latch mechanisms  28 ,  29  may automatically return to their locked positions when the gate  10  is returned to its closed position. 
     FIG. 3 illustrates one embodiment of a latch mechanism  28  in its locked, or latched, condition, and FIG. 4 illustrates the latch mechanism in its unlocked, or unlatched, condition. By the term “unlocked” it is meant that the cam  44  is free to rotate, and/or the pin  42  is not received in the cam  44  and therefore the gate  10  is free to pivot. By the term “locked” it is meant that the cam  44  is blocked from pivoting and the pin  42  is received in the cam  44  and therefore the gate  10  is locked in place. The cam  44  is located in its home position in FIG. 3 such that the notch  54  is aligned with the locking arm  60 . In order to move the latch  28  to its unlatched or unlocked position, the solenoid  72  is activated to retract the piston  68 , as shown in FIG. 4, thereby moving the arm  60  to its disengaged position. The solenoid  72  is preferably activated by a signal emitted by the actuator  32  (FIG. 1) received by the receiver  35  (FIG.  2 ). However, various other means or mechanisms for activating the solenoid  72  may be used. When the piston  68  is retracted as shown in FIG. 4, the arm  60  is pulled out of the notch  54 , and the cam  44  is free to rotate about the center pin  46 . 
     Once the latch  28  is shifted to its unlocked position, the gate  10  can be pivoted from its closed position. When the gate  10  is pivoted from its closed position, this moves the slot  48  relative to the pin  42  (i.e., moves the cam  44 , arm  60  and solenoid  72  to the right in FIG.  4 ), which moves the pin out of the slot  48  as shown in FIG.  5 . As the pin  42  moves out of the slot  48  of the cam  44 , the pin  42  engages side  81  of the slot  48 , thereby rotating the cam  44  about its center pin  46  to its position shown in FIG.  5 . At this point, the cam  44  and the gate  10  are uncoupled from the pin  42  and wall portion  22 , and the gate  10  is free to pivot to its fully opened position. After a predetermined period of time has elapsed, the power to the solenoid  72  is terminated, and the piston  68  extends outwardly to its engaged position shown in FIG. 6, as biased by the spring  74 . The outward motion of the piston  68  causes the arm  66  to move into its engaged position such that the arm contacts the outer face  52  of the generally circular portion  50  of the cam  44 . 
     As shown in FIG. 7, when the gate  10  is swung into its closed position, the cam  44 , arm  60  and solenoid  72  are moved to the left in FIG.  7 . The pin  42  is then received in the slot  48  of the rotatable cam  44 , and the pin  42  engages the side  82  of the slot  48 . This causes the cam  44  to pivot towards its home position. Further movement of the cam  44  (to the left in FIG. 7) causes the cam to rotate about the center rod  46  to its position shown in FIG.  8 . As the cam  44  is rotated, the legs  62 ,  64  of the locking arm  60  ride along the outer face  52 . When the cam  44  begins to near its home position, the leg  64  is located over the notch  54  while the other leg  62  is located on the lobe  56  (FIG.  8 ). The lobe  56  acts as a guiding cam surface and causes the locking arm  60  to pivot slightly about the connecting pin  70 , as indicated by arrow A, thereby urging the leg  64  into the notch  54  by a distance D (see FIG.  8 A). As the cam  44  continues to near the home position, the leg  64  engages a side wall  55  of the notch  54 , which pivots the locking arm about the connecting pin  70  as indicated by arrow B (FIG.  9 ). As the cam  44  continues to pivot, it reaches its home position shown in FIG. 10, and both legs  62 ,  64  are then fully received in the notch  54  as biased by the spring  74 . The pin  66  is then received in a generally circular recess  77  in the arm  60 , which prevents the arm from rotating. After the arm  60  is received in the notch  54 , rotation of the cam  44  in either rotational direction is blocked, and the gate  10  is thereby latched in its closed position. 
     The lobes  56 ,  58  cause the locking arm  44  to rotate about the connecting pin  70  as the cam  44  nears its home position, and thereby ensure that the locking arm  44  engages one of the side walls of the notch  54  (see FIG.  8 A). This, in turn, ensures that the locking arm  44  “catches” in the notch  54  as the gate  10  is swung towards its closed position. Thus, the illustrated latch mechanism  28  arrangement prevents the gate from “swinging through” the latch mechanism  28  and ensures that the latch mechanism catches the gate in the closed position. 
     The latch mechanism  28  illustrated herein may be used when the gate  10  is pivoted in either direction relative the latch mechanism. This provides the user a choice as to which way to swing the gate  10  after it is unlatched. Furthermore, the orientation of the latch mechanism  28  may be reversed such that the pin  42  is located on the gate  10  and the cam  44 , locking arm  60  and the solenoid  72  and associated hardware are mounted onto the wall portion  22 . The gate of the present invention may also be used to block the access of household pets, in which case the actuator is preferably located at a position inaccessible to the pets to prevent accidental activation. 
     Having described the invention in detail and by reference to the preferred embodiments, it will be apparent that modifications and variations thereof are possible without departing from the scope of the invention.