Mailbox alarm

• US 3,909,819 A
• Filed: 04/22/1974
• Issued: 09/30/1975
• Est. Priority Date: 04/22/1974
• Status: Expired due to Term

• Current Assignee: Leslie M. Radford
• Original Assignee: Leslie M. Radford
• Inventors: Radford, Leslie M.
• Primary Examiner(s): Habecker, Thomas B.
• Application Number:
  US05/462,721
• Time in Patent Office: 526 Days
• Field of Search: 340/281 250/239,215
• US Class Current: 340/545.3
• CPC Class Codes: A47G 29/1212 comprising electrical parts

Abstract

Alarm apparatus for indicating when mail has been delivered to a mailbox. A photocell inside the mailbox has an electrical characteristic dependent upon the presence of light in the mailbox, and this electrical characteristic is coupled to an alarm signal device inside a house. The alarm signal device latches on after mail has been delivered and light has entered the mailbox changing the electrical characteristic of the photocell.

Claims

1. Mailbox alarm apparatus comprising:

an enclosed mailbox having an openable door; and

photosensitive means for initiating activation of an alarm signal in response to light coming from outside the mailbox when the door is opened.

2. The apparatus of claim 1 in which the photosensitive means includes:

first means inside the mailbox when the door is closed for presenting at an output an electrical characteristic dependent upon the presence of light in the mailbox; and

second means for coupling the output of the first means to an alarm signal assembly.

3. The apparatus of claim 2 in which the first means includes a photocell presenting a light-dependent resistance at an output.

4. The apparatus of claim 3 in which the photocell is a cadmium-sulfide cell.

5. The apparatus of claim 2 which further includes:

an alarm signal assembly coupled to the output of the first means by the second means.

6. The apparatus of claim 5 in which the alarm signal assembly comprises:

a power supply;

an alarm signal device having a first terminal coupled to the power supply at a first point and having a second terminal; and

switch means coupled between the second terminal of the alarm signal device and the power supply at a point of electrical potential different from that of the first point, for coupling the second terminal of the alarm signal device to the power supply when the output of the first means corresponds to a first condition when light is present in the mailbox.

7. The apparatus of claim 6 in which the second means is a pair of wires.

8. The apparatus of claim 6 in which the alarm signal device is a light and which further includes latching means for maintaining the second terminal of the light coupled to the power supply after the first condition arises.

9. The apparatus of claim 5 in which the alarm signal assembly comprises:

a power supply;

an audible alarm having a first terminal coupled to the power supply at a first point and having a second terminal; and

switch means, coupled between the second terminal of the audible alarm and the power supply at a point of electrical potential different from that of the first point, for coupling the second terminal of the audible alarm to the power supply when the output of the first means corresponds to a first condition when light is present in the mailbox.

10. The mailbox alarm apparatus of claim 1 which additionally includes:

latch means for maintaining activation of said alarm signal after said photosensitive means initiates and after light ceases coming into the mailbox from outside the mailbox whereby after the door is closed the alarm signal remains activated.