GB2282634A - Garage door intruder alarm - Google Patents

Abstract

A garage door intruder alarm is provided on a door lock housing (2), the housing (2) having an outer handle (6) and an inner handle (7) and being secured to a lock mounting plate (8) secured to the inner face of a garage door (9). A base plate (14) and a cover (15) form an enclosure to contain the alarm which comprises a printed circuit board (18) mounting a battery (19), an impact sensor coupled with an impact sensitivity variable tuner, a micro-switch (22) operated upon operation of an internal lock operating pin (13), a light emitting diode (25) a micro-switch 27 operated by pulling of a bandle shaft (5), an audible alarm (28) and a terminal block for external sensing circuits. <IMAGE>

Description

GARAGE DOOR INTRUDER ALARM The invention relates to a garage door intruder alarm, Many alarm systems have been proposed to provide defences against intruders and generally they have been custom-designed and in consequence have been expensive and unduly involved.

According to the invention a garage door intruder alarm for a garage door lock incorporating a housing, a turnable handle mounted in the housing, locking means to prevent the handle from being turned and bolt means operable to lock and unlock the door upon turning of the handle, has alarm means comprising a printed circuit board mounted on the housing, a micro-switch operated when a pulling force is applied to the handle, an impact sensitive switch to be operated when the door on which the alarm is fitted is subjected to impact, alarm indication means such as a warning light, a source of electrical energy, audible alarm means and delay means.

The door lock can be a standard garage door lock modified to accept the alarm means and provided with a plastic enclosure to contain the alarm means. Preferably the source of electrical energy is a battery contained within the enclosure. The door can be provided with wires extending thereover which if cut or broken, by an attempt to make a hole in the door, results in opening of a circuit and sounding of the audible alarm means. In like manner switches may be provided which, in a closed position of the door, are closed by magnets mounted on a door frame and which will be opened if the switches are moved away from the magnets by opening of the door.Tilting of the door handle by means of a pull applied thereto will cause a door handle shaft to tilt and move against the action of a spring to operate a micro-switch and subjecting the door to impact, such as by shouldering the door, will operate the impact sensitive switch.

The invention is diagrammatically illustrated by way of example in the accompanying drawings, in which: Figure 1 is a part sectional side elevation of garage door lock provided with a garage door intruder alarm according to the invention; Figure 2 is a front view of the lock of Figure 1 with a handle removed; Figure 3 is a rear view of a printed circuit board provided in the alarm of Figures 1 and 2; and Figure 4 is a schematic block diagram of a garage door intruder alarm according to the invention.

Referring to the drawings, a garage door intruder alarm generally indicated at 1 has a door lock having a housing 2 from the opposite lateral sides of which arms 3 and 4 project and can be connected to locking bolts in known manner. The arms 3 and 4 are coupled to a shaft 5 which extends through the housing 2 and at its front end mounts an outer handle 6 and at its rear end mounts an inner handle 7. The housing 2 is secured by screws to a lock mounting plate 8 which is secured to the inner face of a garage door 9 by screws 10. The housing 2 has an outwardly directed cylindrical lock cylinder 11 which includes a locking mechanism and has a keyhole 12 in its outer end face.

Projecting from the inner face of the lock housing 2 is an extension pin 13 which can operate the lock 11 from the inside of a garage door in the same manner that it can be operated from the outside by a key inserted in the keyhole 12. Secured on the inner face of the housing 2 by screws is a base plate 14 which together with a cover 15, which can be secured to the base plate by screws 16, forms an enclosure to contain an alarm. Secured within the enclosure by screws 17 is a printed circuit board (PCB) 18 shown in Figure 3.

Mounted on the PCB 18 are a battery 19, an impact sensor 20 coupled with an impact sensitivity variable tuner 21, a micro-switch 22 operated upon operation of the internal lever 13, connections 23 for a light emitting diode 25 which extends through the door 9 and into a handle plate 26 to flash to show that an alarm is installed, a micro-switch 27 operated in conjunction with the shaft 5 as described hereinafter, an audible alarm 28 and a terminal block 29 to which external circuits can be connected, one of which circuits is shown in Figure 3 to include a reed switch 30 mounted at the edge of the door and cooperating with a magnet 31 on a surrounding frame. Wires 32 connecting the reed switch 30 to the terminal blocks 29 can be tracer wires which, if cut, will cause an open circuit to be detected at the terminal block 29.

Figure 1 shows that a shoulder 33 of the outer handle 6 abuts up against a thermoplastics collar 34 in the handle plate 26 and that a cylindrical portion 35 of the inner handle 7 extends through a large clearance hole 36 in the cover 15. Surrounding the shaft 5 between the inner end of the cylindrical portion 35 of the inner handle 7 and the housing 2 are a coiled compression spring 37 and at least one washer 38. The number of washers 38 is dependent upon the thickness of the door thus, for example each washer is for example 1.57 millimetres in thickness and one washer is provided for a door of 19 millimetres thickness, two washers for a door of 17 millimetres thickness, three washers for a door of 15 millimetres thickness and a four washers for a door of 14 millimetres thickness.The micro-switch 27 is mounted between the face of the inner washer 38 and the PCB 18 and will be operated upon a pull applied to the outer handle 6 of greater than 2 millimetres movement. The impact sensor 20, the sensitivity of which is controlled by the variable tuner 21, will give an indication if the door 9 is subjected to impact, such as by being shouldered.

The LED 25 flashes at the outer face of the door at a regular rate whenever the door is locked and the alarm is armed to give a warning to intruders that an alarm system has been installed. If the handle 6 is tried to see whether the door is unlocked, the resulting lateral movement of the shaft 5 will operate the micro-switch 27 and, after a delay, operate the audible alarm 28. The battery 19 can obviate any requirement for mains electrical supply and can be capable of lasting twelve months depending upon the number of times that the audible alarm 28 is sounded. Normal operation of the cylinder lock 11 by a key inserted in the keyhole 12 or by the inner extension 13 activates and disarms the alarm system automatically so that the authorised user is not required to remember that the system is alarmed.

A delay is preferably provided after each setting of the alarm to prevent premature activation and at each setting of the alarm an audible bleep is provided to confirm the arming of the alarm and the condition of the battery.

Referring to Figure 4, an arming circuit 40 is connected to a battery condition sensor 41 and to the LED flasher circuit 42. A delay circuit 43 sets a ten second delay. If a circuit connected to the terminal block 29 is opened, then a circuit 44 sounds a continuous alarm. If the door is subjected to impact, a circuit 45 sounds an instant alarm but if a pull is applied to the external handle 6 a circuit 46 delays for ten seconds operation of the alarm but sounds audible pulses so that an authorised operator can remember that the system is locked and operate the lock before the ten seconds expires and the alarm sounds. The sound provided by the alarm 28 is preferably a two tone police siren type sound which avoids confusion with normal car alarm sounds. A modified version of the system shown can be provided to suit automatic/remotely operated doors which typically use a remote control to transmit open/close instructions to an electric door operator. In such a case alternative means for arming and disarming the system are employed.

Claims (6)

1. A garage door intruder alarm for a garage door lock incorporating a housing, a turnable handle mounted in the housing, locking means to prevent the handle from being turned and bolt means operable to lock and unlock the door upon turning of the handle, the alarm comprising a printed circuit board mounted on the housing, a micro-switch operated when a pulling force is applied to the handle, an impact sensitive switch to be operated when a door on which the alarm is fitted is subjected to impact. alarm indication means, a source of electrical energy, audible alarm means and delay means.

2. A garage door intruder alarm according to claim 1, in which the door lock is a standard garage door lock modified to accept the alarm and provided with a plastics enclosure to contain the alarm means and the source of electrical energy is a battery contained within the enclosure.

3. A garage door intruder alarm according to claim 1 or claim 2, in which the door is provided with wires extending thereover which if cut or broken, by an attempt to make a hole in the door, results in opening of a circuit and sounding of the audible alarm means.

4. A garage door intruder alarm according to any one of claims 1 to 3, in which switches are provided which, in a closed position of the door, are closed by magnets mounted on a door frame and which are opened if the switches are moved away from the magnets by opening of the door.

5. A garage door intruder alarm according to any one of claims 1 to 4, in which tilting of the door handle by means of a pull applied thereto causes a door handle shaft to tilt and move against the action of a spring to operate the micro-switch.

6. A garage door intruder alarm substantially as hereinbefore described and illustrated with reference to the accompanying drawings.