Electronic safety-lock
It is well known that mechanical locks are used for outer doors, main access doors, gates etc., which are usually opened and closed with a key. 
     These known locks are either simple lever tumbler locks, safety cylinder, Yale or sprocket latch locks, the lever tumbler locks being scarcely used now because they are easy to be tampered with, so that safety cylinder or sprocket latch locks are commonly used. 
     These safety locks are mechanically operated with keys and may feature a keyhole on both sides or only on the outside while on the inside the door is opened or closed with a handle or knob. 
     Although it is more difficult to tamper with these cylinder or sprocket latch locks, the slider of the lock and its locking stud may be easily shifted from their closing position when first pulling out the cylinder. 
     This is the reason why combined lever/cylinder locks have been recently introduced, from which the cylinder cannot be pulled out. 
     Electronic locks are also commonly known and specifically used for entrance doors and gates which are automatically opened from inside and with a key from outside. These door locks,are for instance adopted for the entrance doors of buildings with housephones. 
     This invention has the aim to provide a safety-lock essentially designed for electronic actuation and to prevent any kind of tampering and unwanted opening, so that it will be essentially operated by an electromechanical system and may be connected to the general alarm system of the dwelling or more simply to the door lock. This door lock is actuated by a remote control. 
     In short, the key lock according to this invention is consisting of a usually low voltage motor causing by means of a reduction gear, the rotation of a worm screw fitted with a mobile slider bearing the mobile studs that enter the holes or borings drilled in the latch box mounted on the fixed doorwing or in the wall in front of the lock. 
     A mobile rack is secured to the slider and is activated by a gear that may engage a cylinder or sprocket latch by means of a key or knob. 
     The levers or arms used to block the door at floor level or to the doorposts may also be connected to this slider. 
     It follows that activation of the motor in either direction will cause the studs to move forewards thus closing the lock or backwards to open the door lock without actuating the key locked cylinder, although it causes the rack to move in the required sense. 
     The cylinder, rack and studs are only key operated in case of failure of the electric system and their emergency operation mode will be described hereinafter. 
     An electromechanical unit is mounted on the rack which will enable electric operation of the door lock but not its mechanical operation with the key since the latter is only used in emergency cases. 
     The Electronic control system of the door lock is mounted on a control panel and is involving numerous sensors activated by the rack movements. This control panel permits normal operation as well as emergency operation of the door-lock and its connection to the alarm system. This control panel and its circuitry will be described in detail hereinafter. 
     The key-lock subject matter of this invention as outlined above may also feature a built-in automatic latch as normally used ill entrance doors and gates so as to make it easier for the user to adopt this locking system. 
    
    
     The invention in question is illustrated in its practical and exemplifying implementation in the enclosed drawings in which: 
     FIG. 1 shows a frontal view of the inside of the safety-lock according to this invention, with drawn-out lock studs; 
     FIG. 2 shows a side view of the fixed lock plate with the holes in which the studs will engage; 
     FIG. 3 shows a front view of the safety lock illustrated in FIG. 1 with retracted lock studs; 
     FIG. 4 shows the safety lock section according to the 4--4 axis of FIG. 1; 
     FIG. 5 shows the safety lock section according to the 5--5 axis of FIG. 1. 
     FIG. 6 shows an elementary diagram illustrating the operation of the safety lock subject matter of this invention. 
    
    
     With reference to the above drawings, the box-shaped frame 1 of the safety lock is fitted with fastening components by which the box is secured to the mobile wing 2 of the door. 
     This box is housing the motor 3, which usually is a low voltage d.c. motor provided with a driving gear 4 meshing with a driven gear 5 having a diameter apt to ensure a suitable reduction ratio of the rotary movement of the driven gear 5. A worm screw 6 is rigidly mounted on the driven gear 5, the free end of the worm 6 is resting on the support 7 mounted on the wall of the box-shaped frame 1. 
     A threaded slider 8, externally provided with one or more lock studs 9 is keyed onto the worm screw. The lock studs 9 are designed to enter the holes 10 in the lock plate 11 which is in some way secured to the fixed door wing 12 or to the wall around the door. 
     The lower end of the slider is rigidly connected to a rack 13 meshing with a gear wheel 14 which can be operated from outside the door by means of a key 15 and its cylinder 17 by acting against a loaded coil spring located inside the gear wheel 14 or frown inside by means of the knob 16. The key 15 or knob 16 are used in emergency cases as will be explained below. 
     The lower end 18 of the cylinder or sprocket latch 17 lodging the key 15 is cone shaped for the reasons explained hereinafter. 
     A boring 19 is drilled in the lower face of the rack 13 to lodge the pin tooth 20 located on the horizontal flange of an L-shaped ratchet 21 hinged onto the pin 22. This ratchet 21 and its pin tooth or pin 20 are moved downwards by the magnetic action of a coil 23, whereas they are moved upwards by means of the spring incorporated in the coil. 
     In emergency cases, the upwards flange of the ratchet 21 is pushed inwards by the cone-shaped surface 18 of the cylinder 17 which moves inwards when it is pushed by the key used for emergency opening. In case of emergency, this will cause the pin 20 to come out of the boring 19 thus releasing the rack 13 which may thus move freely together with the movements of the lock studs 9 in case of power failure or failure of the electric control system. 
     Furthermore numerous sensors detect the position of the ratchet 21 and rack 13. The first sensor 24 identifies the closed position and complete extraction of the studs 9, whereas a second sensor 25 detects opening and complete retraction of the lock studs of the door. These two sensors 24 and 25 will turn off the motor after the lock studs 9 have completed their draw-out and draw-in travel. 
     Sensor 26 detects lowering of the ratchet 21 and release of the rack 13. If the ratchet 21 is lowered by an opening pulse of the remote control 34 (push button A), the sensor 26 will enable the opening drive of the motor 3. Conversely, the sensor 26 will trigger an alarm system if the ratchet 21 is lowered by the cylinder 17 (when fitting the key in the lock from outside or if ill-intentioned persons should try to hamper with the lock). 
     An additional sensor 27 may be located between the walls facing the door lock and the plate 11 housing the studs 9. This sensor 27 may trigger an alarm should the door be tampered with or broken open. 
     Levers or transmission gears 28 may be connected to the slider 8 actuating other known latching systems such as sliding bars mounted at floor level or on the doorposts. 
     It would be preferable to provide the safety lock here described and operating as an assembly with a normal automatic latch 29 and stud 30, return 31 and internal manual push-button 32. At the end of the rack travel 13, when the door is opened, an electromagnet 33 will be actuated causing opening of the automatic latch 29 and of its stud 30. If the studs 9 of the door lock are already open, it will suffice to unbolt the automatic latch 29 by means of the remote control 34 (push-button A) or by using the manual control push-button 32 from indoors or else by fitting the key 15 in the lock in case of emergency. 
     When the studs 9 are completely retracted to open the door, the key 15 may be slightly further turned in the lock so that the rack 13 during opening, will be able mechanically to activate the automatic latch 29 by means of the lever 37 and pawl 38 and thus completely open the door. 
     Operation of this door lock will be ensured by a remote control 34 provided with only two push-buttons, i.e. push-button A to open and push-button C to close the door as shown in FIG. 6. 
     The wiring diagram of the safety-lock subject matter of this invention is illustrated in FIG. 6 featuring, in addition to the components already shown in the previous figures, the following elements: 
     Low voltage power supply by buffer battery 35 
     Opening Control CA 
     Closing Control CC 
     Radio Controlled Receiver for opening RCA 
     Radio Controlled Receiver for closing RCC 
     Timer for opening TA 
     Timer for closing TC. 
     The sensor 26 can also be used to actuate the alarm system (if any) which may also be triggered by the sensor 27 if the door is tampered with. 
     Based upon the foregoing, the door lock is functioning as follows: 
     Normal Electric Opening Circuit 
     When pressing the opening push button A of the remote control 34 from inside or outside the room closed by a door fitted with the door lock in question, the magnet 23 is energized moving the ratchet 21 and extracting the lock pin 20 from the rack 13. 
     The downwards movement of the ratchet 21 energizes the sensor 26. The opening timer TA will keep the ratchet 21 released for a short time after the motor has been turned ON to prevent the ratchet 21 from re-entering the boring 19 in the rack 13. 
     The motor is driven in the direction set by the remote control 34 and provides for retraction of the mobile studs 9 closing the lock. 
     Pickup of the electromagnet 23 ceases automatically so that the ratchet 21 is pushed upwards by the magnet spring 23 while the pin 20 slides along the lower surface of the rack 13 during its traverse. When the rack 13 has completed its traverse, the electromagnet 33 is energized causing opening of the automatic latch 29. The lock is now open and the sensor 25 turns the motor 3 OFF. 
     Normal Electric Closing Circuit 
     When pressing the closing push button C of the remote control 34 from inside or outside the room, the polarity of the current powering the motor 3 is reversed from CA to CC. 
     The timer TC has to keep the motor power circuit closed during all closing stages until the circuit is disconnected by the sensor 24. At the end of the traverse, the tooth 20 of the ratchet 21 enters the boring 19 in the rack 13 thus re-establishing the mechanical interlock. At the same time, the automatic latch 29 is automatically reset in its closing position. 
     Normal Electric Closing and Opening Control with Alarm System 
     In this case, the alarm may be connected or disconned by the sensor 26. The alarm is disconnected when the ratchet 21 is lowered to release the rack, whereas it is automatically reset when the ratchet 21 is brought in rack interlock position. The alarm is triggered whenever lowering of the ratchet 21 is not activated by the opening push button. A of the remote control 34. 
     Manual Operation of the Door Lock 
     Manual control is required in case of power failure or when the buffer battery drops below a given minimum charge level. 
     In such case the remote control (push-button A) is used to disconnect the alarm system so that a key 15 can be fitted into the cylinder 17. 
     If the key is fitted into the lock before the push-button A of the remote control 34 has been disconnected, the alarm system will be triggered thus indicating that the lock is being tampered with by ill-intentioned persons. 
     By fitting the key into the lock, the cylinder 17 moves inwards pressing its conical surface 18 against the upwards flange of the ratchet 21 which will rotate and release the rack 13 by pulling the pin 20 out of its boring 19. While the cylinder 17 moves inwards, it meshes with the gear wheel 14 which controls opening and closing of the rack 13. 
     When the mobile studs 9 closing the door are completely extracted, the key 15 is turned some more so that the rack 13 will be able mechanically to activate the automatic latch 29 by means of the lever 37 and the pawl 38 to ensure complete opening of the door. 
     The door may also be opened manually from inside the room by adopting a key-based system as described above or else by means of a knob 16, after the rack 13 has been manually released, for example by a pin tooth 36 connected to the ratchet 21 as shown in FIG.5. 
     Manual closing of the door is achieved by turning the key or knob in the direction opposite to the sense used for opening. The spring of the magnetic coil 23 will reset the lock of the rack 13. 
     At this point it will be necessary to actuate the push-button C of the remote control 34 to reset the alarm system. 
     Operation of the Automatic Latch when the Safety Lock is Inactive in Open Position 
     The automatic latch 29 may be opened from outside by turning the key 15 in the proper direction or from inside by pressing the push-button 32 as is normally done with known automatic latches. 
     It follows that the safety lock according to this invention is extremely easy to use and safe against tampering.