| 摘要 |
A pneumatic screwing device includes a spindle for rotatably supporting a screwing tool, a pneumatically drivable rotor for rotating the spindle and a stator for housing the rotor. A gap is defined between the rotor and the stator to receive pressurised air and a supply conduit in the stator delivers pressurised air to the gap. Discharge conduits in the stator discharge pressurised air from the gap. In order to make the pneumatic screwing device more efficient than known devices, there is provided an expansion chamber in communication with the discharge conduits for expanding the pressurised air, the expansion chamber being positioned on an opposite side of the spindle with respect to the rotor and being in communication with the atmosphere. A switch for switching a screwing direction of the pneumatic screwing device includes seats arranged for engaging with locking elements that are slidably associated with the screwing device for maintaining the switch in an operating position corresponding to a desired screwing direction of the device. In order to make the switch more reliable and easier to handle, three seats are provided that are arranged in sequence, the locking elements engaging in the operating position with two of the three seats. |
