Quiet Alarm Clock

The invention, together with additional objects, features and advantages thereof, will be best understood from the following description, the appended claims and the accompanying drawings in which:

FIG. 1 is an exploded perspective view of a quiet alarm clock in a presently preferred embodiment of the invention;

FIG. 2 perspective view of the clock module in FIG. 1;

FIG. 3 is a fragmentary top elevational view of the clock module panel exposed; and

FIG. 4 is an electrical schematic diagram of the quiet alarm clock illustrate in FIGS. 1-3.

A quiet alarm clock 10 in accordance with a presently preferred embodiment of the invention comprises a generally rectangular enclosure 12 having an open base 14 and a cover 16 secured thereto. A circuitboard assembly 18 is secured along the front edge within base 14 adjacent to a rotary electric motor 20 having an output shaft coupled to an eccentric 22. A battery platform 24 is captured within base 14 and held in position by ribs 26 integral with the side walls of base 14 that engage opposed notches 28 in battery platform 24. A pair of AA batteries 30 are removably positioned within corresponding pockets on platform 24 adjacent to the lateral side edges thereof, and are electrically connected to circuitry 18 and motor 20. A generally rectangular pocket is formed by an opening 32 in cover 16 and the underlying portion of battery platform 24. An electronic clock module 34 is removably positioned within opening 32, and is secured therein by snap-fit engagement of opposed mating electrical connectors 36, 38 on the base of clock module 34 and the upper surface of battery platform 24 respectively. With clock module 34 removed, batteries 30 may be selectively replaced within battery platform 24.

Clock module 34 includes a removable slide-cover 38 (FIG. 2) for replacement of the lithium battery 40 that powers the clock module. On the upper surface of clock module 34, there are disposed an operator panel 42 and an adjacent LCD alphanumeric display 44. Display 44 displays the time, AM or PM, and an indication whether the alarm is turned "ON". The various control switches on panel 42, to turn the alarm "ON" or "OFF" and to set the day and alarm times, are protected by a hinged flap panel 46 to prevent accidental operation of these switches. Clock module 34 also has a momentary switch 48 to light the display and operate a "snooze" function, which stops alarm vibrations and turns them "ON" again after four minutes.

FIG. 4 is an electrical schematic diagram of the alarm circuit 18. Clock module 34 is a digital alarm clock (Integrated Display Technology, Ltd., Alarm Clock Model 63706). The audible alarm is removed and the two wires from the audible alarm output of module 34 are attached to the alarm circuit at connecters 36, 38. The alarm signal passes through a filter circuit 54, 55, 56 and a diode 57 for reverse voltage protection. The signal then turns "ON" a transistor 58 that completes a circuit from batteries 30 to motor 20. Eccentric weight 72 (FIG. 1) on the motor shaft causes vibration when the motor rotates. The other components, two diodes 61 and 62 and a resistor 63, are to filter the electrical noise from the motor brushes. If it is desired to activate the alarm from an external signal source, this source can be connected to the auxiliary input 53 and ground 52 terminals. For example, the alarm circuit may be connected to a microphone and amplifier to alert a hearing person to noises such as a ringing telephone, a smoke alarm, etc. The clock module may also drive external audible alarm, for example, through an auxiliary output 51.