Abstract: A pneumatic screw driver includes: a tool body; a nose portion; a main air chamber; a hammering cylinder; a driver bit integrally combined with a hammering piston in the hammering cylinder; an air motor; a valve housing provided in an air passage between the main air chamber and the air motor; a stop valve piston provided in the valve housing; a stop valve stem coaxially provided with the stop valve piston; a timer chamber connected to the hammering cylinder; a first pipeline and a second pipeline respectively formed at upper and lower positions in a lower portion of the stop valve stem; and a upper end proximal portion of a contact member provided slidably in a driving direction. The upper end proximal portion of the contact member is provided engageably with the stop valve stem. The first pipeline and the second pipeline are arranged so as to close the first pipeline after closing the second pipeline by moving the stop valve stem upward from a bottom dead center.

Abstract: A pneumatic screw driver includes: a tool body; a nose portion; a main air chamber; a hammering cylinder; a driver bit integrally combined with a hammering piston in the hammering cylinder; an air motor; a valve housing provided in an air passage between the main air chamber and the air motor; a stop valve piston provided in the valve housing; a stop valve stem coaxially provided with the stop valve piston; a timer chamber connected to the hammering cylinder; a first pipeline and a second pipeline respectively formed at upper and lower positions in a lower portion of the stop valve stem; and a upper end proximal portion of a contact member provided slidably in a driving direction. The upper end proximal portion of the contact member is provided engageably with the stop valve stem. The first pipeline and the second pipeline are arranged so as to close the first pipeline after closing the second pipeline by moving the stop valve stem upward from a bottom dead center.

Abstract: A bag binder comprises; a binding-piece feeding member for feeding a binding piece to a position adjacent to the bag, the binding piece made of a synthetic resin and including a pair of leg portions for binding the bag; a crossing member for crossing the leg portions by pressing the leg portions of the binding pieces; and a bonding member for bonding the leg portions of the binding pieces each other so as to crosswise engage a crossed portion of the leg portions each other.