| 摘要 |
<p>A head unit for vacuum cleaner pipes including a chamber (100) having an air intake (110) and a suction duct (120) and also a piston (300) inside the chamber. The piston is movable from the intake to a position inside the chamber with the aid of a negative pressure caused by air drawn out through the suction duct, and with the aid of a spring member (311) is movable back when the negative pressure in the chamber is less than the force of the spring. The piston (300) is provided with an opening (320) capable of being closed by means of a valve (200); which valve with the aid of guiding devices (210, 220) is arranged so as to be capable of closing the opening (320) when the piston (300) is moved from the first position towards the second position; the valve with the aid of stop and spring devices (240, 211) being arranged so as to be capable of opening the opening (320) at essentially the same time as, but preferably slightly before the piston reaches the second position, so that the negative pressure in the chamber is less than the force of the spring member.</p> |
