MANUALLY OPERATED FASTENING DEVICE

An impact stapler (100) includes an actuator mechanism (110) comprising a firing lever (180) pivotally mounted on a stapler housing (102) and operable by an operating lever (160) for raising a striker (112) against the bias of an actuator spring (240). The firing lever (180) has a front tip (190) which is positioned to engage a tab (272) on the striker (112) when the operating lever (160) is actuated to raise the striker (112) and which is shifted laterally to disengage the front tip (190) from the tab (272) to release the striker (112) for actuation by the actuator spring (240) after the striker (112) is raised. The impact stapler (100) includes a resilient finger (292) for shifting the firing lever (180) laterally to a rest position with the front tip (190) underneath the tab (272) on the striker (112). A stop (295) engages the firing lever (180) in its rest position to limit the bending of the resilient finger (292) and to locate the front tip (190) in a predetermined lateral position relative to the tab (272) on the striker (112).