Patent ID: 7414539

Claim:
An alarm device, comprising a casing, said casing housing therein a reel for taking up a string, a coil spring for providing power for taking up the string around the reel, a switching-on projection means which is arranged in the circumference of the reel and which is adapted to kick a switch when the reel is rotated by the pulling-out of the string or the pulling-in of the string due to the coil spring, said switch comprising an alarm operation switch adapted to be turned on when the switching-on projection means has kicked the switch by the pulling-out of the string or the pulling-in of the string due to the coil spring, an alarm sound generating device which sounds an alarm due to the operation of the alarm operation switch, and a battery which serves to give power to the alarm sound generating device, said string being provided at a free end thereof with a fixing means which can be secured to a predetermined spot, while the casing comprises an attachment means for attaching the casing itself, that the casing is provided in the center of the rear surface thereof with an engaging slot, and the casing of the device is placed on an attachment plate in such a manner that said engaging slot is made to engage a split pin provided in the center of the attachment plate, so that the casing can be freely rotated about the split pin, and that the alarm device proper is detachably attached to the attachment plate.