Self-contained door alarm device

• US 4,194,193 A
• Filed: 11/25/1977
• Issued: 03/18/1980
• Est. Priority Date: 11/25/1977
• Status: Expired due to Term

• Current Assignee: Larry Mcdonough
• Original Assignee: Larry Mcdonough
• Inventors: McDonough, Larry
• Primary Examiner(s): Swann, III, Glen R.
• Application Number:
  US05/854,646
• Time in Patent Office: 844 Days
• Field of Search: 340/545, 340/546, 200/61.62, 200/61.93
• US Class Current: 340/549
• CPC Class Codes: G08B 13/08 by opening, e.g. of door, of window, of drawer, of shutter, of curtain, of blind

Abstract

A self-contained door alarm device is constructed with a housing, preferably fabricated from a high-strength insulator, such as ABS plastic, adapted to be secured above the upper edge of the door, to the doorframe. The alarm device contains a battery-operated tone generator operating in the audible frequency range, coupled to a small speaker. The power supply, preferably in the form of dry-cell batteries, is connected to the tone generator by a switch comprising a conductive strip mounted internally to the device housing, and provided with an elongated slot, and a conductive elastic spring anchored inside the housing and extending downwardly through the aforementioned slot to a position interfering with the plane of travel of the door upper edge. In the case of doors opening outwardly, the spring contact may be operated by a bracket attached to the door panel, along its upper edge. Movement of the spring contact due to entrainment by the door causes contact with the conductive strip and powers the tone generator, which in turn causes a tone to be emitted by the speaker.

Claims

1. A self-contained alarm device, adapted to provide an audible signal upon the opening of a door, comprising:

enclosure means comprising a mounting plate adapted to be secured to the door frame above said door,

a DC power source, secured within said enclosure,

an electrically powered sound signal source for said audible signal, adapted to be powered from said DC power source and connected thereto by means of an electrically conducting path,

a switch in said conducting path adapted to interrupt current flow in said path with the door in a closed position,

said switch comprising an electrically conductive planar element proximate to, and insulated from, the inner face of said enclosure at the basal surface thereof,

coaxial orifices in said conductive element and said basal surface, with the orifice in the latter increased in size with respect to the orifice in the former,

a cantilevered conductor depending from a fixed anchor within said enclosure and passing through said orifices in an alignment spaced from the peripheries thereof in an unloaded state, and

actuator means for said switch responsive to movement of said door toward an open position, and comprising cam means affixed to said cantilevered conductor, further depending from said enclosure and adapted to be entrained by said door upon the movement thereof toward said cam into said open position,

wherein one leg of said conductive path is terminated at said conductive element and one leg is terminated at said anchor, thereby allowing current flow in said path when said cam means is entrained by the door and said cantilevered conductor is deflected against the perimeter of said orifice in said conductive element.

2. The self-contained alarm device of claim 1, wherein said cantilevered conductor and said cam means are constructed from an elongated, wire-like conductor, and wherein said cam means include a curvilinear, re-entrant segment in a plane substantially orthogonal to the inner face of said door.

3. The self-contained alarm device of claim 2, wherein a stress-relieving, flexurally weak, intermediate portion is interposed along said wire-like conductor between said cantilevered conductor and said cam means.

4. The self-contained alarm device of claim 3, wherein said intermediate portion is in the form of a re-entrant, circular loop tangent to said cantilevered conductor.

5. The self-contained alarm device of claim 1, wherein said DC power source includes a battery.

6. The self-contained alarm device of claim 5, wherein said battery is a dry cell.

7. The self-contained alarm device of claim 6, wherein said dry cell is rechargeable, and said DC power source further includes a charger therefor.

8. The self-contained alarm device of claim 1, further comprising:

cam-operator bracket means, adapted to be affixed to said door, encompassing said cam means, whereby a departure of said door from the closed position, in a direction directed away from said cam means, causes said cam means to be entrained by said bracket means, and to deflect said cantilevered conductor into contact with said orifice in said conductive element.

9. As an article of commerce, a self-contained alarm device, adapted to provide an audible signal upon the departure of a door panel from a normally closed position, comprising:

an enclosure, including a mounting plate adapted to be secured to the door frame above said door,

a DC power source comprised of batteries housed within said enclosure,

an electrically powered sound signal source for said audible signal affixed to said enclosure and adapted to be powered from said DC source,

conductor means, including normally open switch means, interconnecting said DC source with said sound signal source,

actuator means for said switch means, responsive to the motion of said door toward an open position, and

bracket means, affixable to said door panel, proximate to the upper edge thereof, encompassing said actuator means between said door panel and a lateral segment of said bracket means.

10. The article of commerce of claim 9, further comprising:

charger means for said batteries.

11. The article of commerce of claim 10, wherein said batteries are comprised of at least one rechargeable dry cell.

12. The article of commerce of claim 9, wherein said batteries include at least one dry cell.