US Patent 7438668 Hurdle

A hurdle has contiguous trigger tubes along the telescoping tubes. A trigger mechanism inside each trigger tube is used to adjust the height of the hurdle. The trigger mechanism contains a pivoting vertical rod with an inwardly directed perpendicular upper end that extends out of the hole in the trigger tube to form a button and an outwardly directed perpendicular pin at its lower end that engages one of the holes in the upright. The vertical rod has a horizontal pivot bar attached midway along its outward surface. The lower end of the vertical rod is connected to a spring compressed within the trigger tube that forces the pin inwardly and that is further compressed when the button is pushed to release the pin.