Manhole insert and tether apparatus and method

A manhole insert and tether apparatus comprising a generally pan-shaped insert body including an insert bottom having a tether opening and terminated by an upward-standing, continuous side wall having a top edge, for seating in a manhole having a manhole wall and a manhole shoulder;

• at least one pressure relief valve extending through said insert bottom for releasing pressure in the manhole;
• a rim shaped in said top edge of said side wall for engaging the shoulder of the manhole and supporting said insert body on the shoulder;
• a pair of loops adapted to be fixedly attached to the manhole wall in substantially diametric opposition with respect to each other;
• a flexible tether of selected length having one end extending through said tether opening in said insert bottom and the opposite end of said tether extending through said loops and attached to said insert bottom in spaced relationship with respect to said tether opening;
• and a tether lock slidably engaging said one end of said tether for selectively locking on said tether and securing said insert body in the manhole.

A method of locking a manhole insert in a manhole beneath a manhole cover and preventing unauthorized entry into the manhole, comprising the steps of seating a manhole insert in the manhole;

• providing an opening in said manhole insert;
• securing a pair of tether mount loops in the manhole in spaced relationship with respect to each other;
• extending a flexible tether through said opening and said tether mount loops and securing one end of said flexible tether to said manhole insert;
• seating the manhole insert in the manhole;
• and sliding a tether lock on the opposite end of said flexible tether, whereby said manhole insert is secured in the manhole responsive to pulling said opposite end of said flexible tether through said opening to tighten said flexible tether between said manhole insert and said tether mount loops, sliding said tether lock on said opposite end of said flexible tether to said insert body and securing said tether lock on said flexible tether.