In the planner area, an employee was piling lumber that was being transported by a lumber chain. One of the chains became jammed. The employee reached between the chain way because the chains were doubled over. Energy was stored in the gear box due to the jam. The employee manually tugged the belt associated with the belt/pulley mechanism for the 2 hp motor and gear box. The motor/gear box drives the chains. When the employee tugged on the belt, it released the stored energy from the jammed gear box. The employee's fingers went into the nip point created by the belt/pulley and three fingers on the right hand were severely fractured. The ring finger also had skin removed.