Suction unit and autonomous vacuum cleaner

A suction unit for a self-driven vacuum cleaner, said suction unit comprising:

• a drive system including at least first and second drive members for moving the suction unit on a surface to be treated;
• a chassis supporting the drive system;
• a nozzle for removing matter from the surface to be treated, said nozzle having an opening that faces the surface to be treated during an operation and an interior space in communication with said opening;
• an outlet in communication with the interior space of the nozzle, said outlet being arranged for communication with a fan unit for effecting airflow through the suction unit during operation;
• and
• a coupling device arranged between the nozzle and the chassis for movably coupling the nozzle to the chassis for motion in directions toward and away from the surface to be treated, said coupling device being adapted, in response to the occurrence of a reduction of air pressure in the interior space of the nozzle that is indicative of a reduced airflow through the nozzle, to simultaneously produce a force for moving the nozzle away from the surface to be treated and a counter force for moving the chassis and the at least first and second drive members toward said surface to be treated, said force and simultaneous counter force, respectively, operating to prevent a movement-stopping seal from developing between the nozzle and the surface to be treated and to increase traction of the at least first and second drive members, thereby assisting movement of the suction unit;
• wherein the coupling device further comprises an arm that is pivotally mounted to the chassis at a pivot point and extends substantially parallel with relation to the surface to be treated, the nozzle being supported by the arm.

An autonomous vacuum cleaner comprising:

• a suction unit including:
• a drive system including at least first and second drive members for moving the vacuum cleaner on a surface to be treated;
• a chassis supporting the drive system;
• a nozzle for removing matter from the surface to be treated, said nozzle having an opening that faces the surface to be treated during operation and an interior space in communication with said opening;
• an outlet in communication with the interior space of the nozzle via a coupling device, said outlet being arranged for communication with a fan unit for effecting airflow through the suction unit during operation;
• the coupling device being arranged between the nozzle and the chassis for movably coupling the nozzle to the chassis for motion in directions toward and away from the surface to be treated, said coupling device being adapted, in direct response to the occurrence of a reduction of air pressure in the interior space of the nozzle that is indicative of a reduced airflow through the nozzle, to simultaneously produce a force for moving the nozzle away from the surface to be treated and a counter force for moving the chassis and the at least first and second drive members toward said surface to be treated, said force and simultaneous counter force, respectively, operating to prevent a movement-stopping seal from developing between the nozzle and the surface to be treated and to increase traction of the at least first and second drive members, thereby assisting said movement of the vacuum cleaner;
• a dust chamber in communication with the fan unit for receiving the matter;
• and
• the fan unit.