Abstract: An impact tool has an anti-topping mechanism (“ATM”) adapted to reduce the rotational frictional force between the contact surfaces of the hammer and anvil to prevent topping. If topping still occurs, the ATM quickly breaks the topped condition. The ATM may reduce the rotational frictional torque between the hammer and anvil of an impact mechanism or provide increased the rotational friction acting on the anvil from adjoining elements of the tool thus tending to hold the anvil (by heightened rotational friction) while the hammer can be broken free. ATM mechanisms include hammer and jaw surfaces angled at interface points; stepping either the hammer or anvil jaw surfaces so that only the innermost portions interact; rounding or crowning either or both of the anvil and hammer jaw surfaces so minimal portions of the jaws are ever topped; and software-controlled detection and breaking of a topped condition. In torque-controlled impact tools, these mechanisms decrease the risk of accuracy or repeatability issues.

Abstract: An impact tool has an anti-topping mechanism (“ATM”) adapted to reduce the rotational frictional force between the contact surfaces of the hammer and anvil to prevent topping. If topping still occurs, the ATM quickly breaks the topped condition. The ATM may reduce the rotational frictional torque between the hammer and anvil of an impact mechanism or provide increased the rotational friction acting on the anvil from adjoining elements of the tool thus tending to hold the anvil (by heightened rotational friction) while the hammer can be broken free. ATM mechanisms include hammer and jaw surfaces angled at interface points; stepping either the hammer or anvil jaw surfaces so that only the innermost portions interact; rounding or crowning either or both of the anvil and hammer jaw surfaces so minimal portions of the jaws are ever topped; and software-controlled detection and breaking of a topped condition. In torque-controlled impact tools, these mechanisms decrease the risk of accuracy or repeatability issues.