Location monitoring system

• US 5,357,254 A
• Filed: 07/26/1993
• Issued: 10/18/1994
• Est. Priority Date: 09/18/1985
• Status: Expired due to Term

• Current Assignee: Carl L.C. Kah Jr
• Original Assignee: Carl L.C. Kah Jr
• Inventors: Kah, Carl L. C. Jr.
• Primary Examiner(s): Hellner, Mark
• Application Number:
  US08/097,156
• Time in Patent Office: 449 Days
• Field of Search: 342/42, 342/385, 342/386, 340/539, 340/573
• US Class Current: 342/42
• CPC Class Codes: G08B 21/0216 Alarm cancellation after generation
• CPC Class Codes: G08B 21/0227 System arrangements with a plurality of child units
• CPC Class Codes: G08B 21/023 Power management, e.g. system sleep and wake up provisions
• CPC Class Codes: G08B 21/0263 System arrangements wherein the object is to detect the direction in which child or item is located
• CPC Class Codes: G08B 21/0286 Tampering or removal detection of the child unit from child or article
• CPC Class Codes: G08B 21/0288 Attachment of child unit to child/article

Abstract

A location monitoring system is provided having a radio frequency transmitter for a person or object and radio frequency receiver for someone to monitor movement of the person or object, the receiver sounding an alarm at a predetermined time after failure to receive a signal. The transmitter is made having an intermittent transmitted signal and the receiver is made having an off-timer to coordinate with the intermittent signal, the off times saving battery power. The radio frequency receiver has an electronic switching device controlled by the radio frequency transmitter for sounding an alarm. An antenna is located in part of the carrying strap of the transmitter. The radio frequency transmitter can have various devices for sounding the alarm.

Claims

1. A microwave receiving device for receiving a signal from a microwave transmitting device, said receiving device and transmitting device being mounted on relatively movable objects, the microwave receiving device having a microwave receiving circuit means, said receiver circuit means having range determination means for determining the range to the transmitter in order to discriminate between at least two ranges, said two ranges being a short range and a longer range, said last named means including a variable position switch, said variable position switch having a short range setting and a longer range setting, an alarm means, an electronic switching means positioned between said alarm means and said range determination means, said range determination means sending an output signal to said electronic switching means to control it, said electronic switching means will not permit said alarm means to be actuated when the range is determined to be less than said set range, said electronic switching means will permit said alarm means to be actuated when the separation range between transmitter and receiver exceeds said set range.

6. A microwave receiving device as set forth in claim 1 wherein said short range is 25 feet and said longer range is 100 feet.

2. A radio frequency receiving device for receiving a signal from a radio frequency transmitting device, said receiving device and transmitting device being mounted on relatively movable objects, the radio frequency receiving device having a radio frequency receiving circuit means, said receiving circuit means having range determination means for determining the range to the transmitter, said last named means including a selectable variable position means for setting one of a plurality of ranges, an action instruction means connected to said range determination means through an electronic switching means positioned between said action instruction means and said range determination means, said range determination means sending an output signal to said electronic switching means to control it, said electronic switching means will not permit said action instruction means to be actuated when the range is determined to be less than said set range, said electronic switching means will permit said action instruction means to be actuated when the separation range between said transmitter and said receiver exceeds said set range.

8. A radio frequency receiving device as set forth in claim 2 wherein said plurality of ranges has a short range and a long range.

9. A radio frequency receiving device as set forth in claim 8 wherein said short range is 25 feet and said long range is 100 feet.

3. A radio frequency receiving device having antenna means for receiving a signal from a radio frequency transmitting device, said antenna means having good directional sensitivity to locate the direction of the transmitting device from the receiving device, said receiving device also having range means for determining the range to the transmitting device, the range means also including means for selecting one of a plurality of action ranges for the receiver circuit to control an electronic switching means, the transmitter and receiver being mounted on relatively movable objects, such that when the preselected range is exceeded the electronic switching means is turned "ON" and the direction to the object may be determined.

4. A radio frequency receiving device having an antenna for receiving a signal from a radio frequency transmitting device, said receiving device and transmitting device being mounted on relatively movable objects, the radio frequency receiving device having a radio frequency receiving circuit means and an amplifier for amplifying the signal received from the antenna, said amplifier having means for changing its gain for providing different sensitivity levels in order to discriminate between at least two ranges of transmitting device location relative to said receiving device, said last named means including a variable position switch for setting one of a plurality of ranges, an alarm means, an electronic switching means positioned between said amplifier and said alarm means, said amplifier sending its output signals to said electronic switching means to control it, said electronic switching means will not permit said alarm means to be actuated when the received output signal is at or above a predetermined strength, said electronic switching means will permit said alarm means to be actuated when the received output signal is below a predetermined strength.

7. A radio frequency receiving device as set forth in claim 4 wherein said two ranges are 25 feet and 100 feet.

5. A radio frequency receiving device having two antenna means for receiving a signal from a radio frequency transmitting device, a first antenna means having a minimum directional sensitivity for general monitoring, a second antenna means having good directional sensitivity for directional monitoring, switching means for selecting between said first and second antenna, said second antenna being used to locate the direction of the transmitting device from the receiving device, said receiving device and transmitting device being mounted on relatively movable objects, the radio frequency receiving device having a radio frequency receiving circuit means and an amplifier for amplifying the signal received from the antenna, said amplifier having means for changing its gain for providing different sensitivity levels in order to discriminate between at least two ranges of transmitting device location relative to said receiving device, said last named means including a variable position switch, an alarm means, an electronic switching means positioned between said amplifier and said alarm means, said amplifier sending its output signals to said electronic switching means to control it, said electronic switching means will not permit said alarm means to be actuated when the received output signal is at or above a predetermined strength, said electronic switching means will permit said alarm means to be actuated when the received output signal is below a predetermined strength.