Method and Apparatus for Pet Tethering Device

Abstract

A tether device allows a pet to roam freely within a pre-defined area of space while restricting the pet from moving beyond the perimeter of a pre-defined area. The location of the perimeter is programmed into the tether device by providing distance and angular coordinates of the distal end of the tether from the tether device. The location of the pet, once attached to the tether device is likewise determined by the combination of coordinates. When the microcontroller senses the pet is nearing the perimeter of the pre-defined area, a lock mechanism is activated which prevents further movement in a direction that will exceed the perimeter, and only allows movement of the pet away from the perimeter. The lock mechanism may have a cushioning mechanism to prevent a hard stop. The tether device can also generate alarm tones to alert the user and/or train the pet.

The invention claimed is: 
     
         1 . A pet tethering apparatus which allows the pet to freely roam within a pre-defined area of space while restricting movement of the pet beyond the pre-defined area of space by activating a locking mechanism comprising:
 a spool of tether with a distal end of the tether for attachment to a pet, rotatable about a first shaft to dispense or retract an amount of tether;   at least one mechanism for determining at least one positional parameter;   at least one locking mechanism in connection with the spool of tether which when activated, restricts continuous payout of the tether; and   a retraction mechanism disposed in connection between the first shaft and the spool of tether to exert a force on the spool of tether which urges the spool of tether to rotate in a direction of retraction of the distal end of the tether.   
     
     
         2 . The apparatus of  claim 1  wherein the at least one mechanism for determining at least one positional parameter is a payout sensor located in a position to sense the direction of rotation of the spool of tether. 
     
     
         3 . The apparatus of  claim 1  further comprising
 a second shaft about which the distal end of the tether rotates. 
 
     
     
         4 . The apparatus of  claim 3  wherein the at least one mechanism for determining at least one positional parameter is a rotational sensor located to sense the angular direction of the distal end of the tether. 
     
     
         5 . The apparatus of  claim 1  wherein the at least one locking mechanism is disposed on the surface of a spool insert in connection with the spool of tether. 
     
     
         6 . The apparatus of  claim 5  wherein the at least one locking mechanism is a ratchet and pawl mechanism. 
     
     
         7 . The apparatus of  claim 6  wherein the pawl mechanism further comprises a spring and a solenoid disposed in contact with a stator plate which is disposed adjacent to the spool insert. 
     
     
         8 . The apparatus of  claim 5  further comprising a torsion spring in connection with the spool insert and the spool of tether. 
     
     
         9 . The apparatus of  claim 1  wherein the retraction mechanism is a coil spring disposed at one end of the first shaft. 
     
     
         10 . The apparatus of  claim 1  wherein the retraction mechanism is a coil spring disposed in overlap with at least a portion of the first shaft. 
     
     
         11 . The apparatus of  claim 1  wherein the first shaft has an axis that is perpendicular to an axis of the second shaft. 
     
     
         12 . The apparatus of  claim 1  wherein the first shaft has an axis that is parallel to an axis of the second shaft.