US Patent 9308599 Welding gun with debris removal and motor cooling

A welding gun includes a handle portion comprising a motor configured to move electrode wire through the welding gun. A diffuser comprises an interior chamber and a plurality of openings defining exit passages from the interior chamber to an exterior of the diffuser. A barrel is located between the diffuser and the handle portion and supplies to the diffuser from the handle portion. A contact tip extends from the diffuser and comprises a front portion, a rear portion, and a contact tip bore extending therethrough configured to receive the electrode wire. A diffuser insert is disposed within the interior chamber of the diffuser, including an insert bore extending therethrough configured to receive electrode wire, and an outer surface configured to direct debris from within the interior chamber of the diffuser towards exit passages to discharge the debris. The handle portion is configured to direct a flow of the shielding gas over the motor to cool the motor.