摘要 |
A clamp rod (5) is vertically movably inserted into a housing (3). The housing (3) has a lower end wall (3b) formed with a detecting hole (58) substantially concentrically with an axis of the clamp rod (5). The detecting hole (58) has a peripheral surface opened to provide at least one inlet hole (71, 72) for supplying compressed air. A detecting member (62) is vertically movably fitted into the detecting hole (58). The detecting member (62) has an outer peripheral surface provided with a closing surface (68) which closes an opening portion (71a, 72a) of the inlet hole (71, 72) and with a recess (69) which communicates the opening portion (71a, 72a) with the outside air. The clamp rod (5) has a downwardly oriented projection (5a). The projection (5a) is connected to the detecting member (62) so that it can make a relative movement radially. <IMAGE> |