a counterbalance mechanism for counterbalancing weight of a bottom - hinged door includes an operator handle , a hoist rod pivotally connected at one end to the operator handle and at an opposite end thereof to the door near a bottom region thereof . a force accumulator assembly is provided which includes a force biasing member which accumulates and dissipates a bias force when opening and closing the door , respectively , to provide mechanical counterbalance to the weight of the door . a bellcrank assembly operatively connects the operator handle to the force accumulator . in such a manner , weight counterbalancing of the door is achieved .