Vacuum cleaner

Abstract

A vacuum cleaner is provided with a chassis and a suction nozzle coupled with the chassis for both vertical and horizontal movement relative to the chassis. The nozzle can be configured to automatically move vertically upon encountering a predetermined amount of resistance to forward or rearward movement of nozzle over a surface to be cleaned.

What is claimed is: 
     
         1 . A vacuum cleaner, comprising:
 a housing including an upright unit having a handle operably coupled to a base unit, the base unit including a chassis having a carriage fixed to the chassis and wheels coupled to the carriage;   a nozzle unit with a suction nozzle;   a suction source in fluid communication with the suction nozzle and adapted for generating a working airstream along a working air path;   a mechanical linkage coupling the nozzle unit to the carriage of the chassis, wherein the mechanical linkage comprises at least two degrees of freedom to displace the nozzle unit relative to the surface to be cleaned, independently of the chassis, such that the suction nozzle can raise and float relative to the chassis wherein the mechanical linkage is configured to automatically lift the suction nozzle away from the surface to be cleaned upon a predetermined force being applied to the nozzle unit during movement of the base unit across the surface to be cleaned; and   a working air duct forming at least a portion of the working air path from the suction nozzle to the suction source, the working air duct adapted for accommodating the float of the suction nozzle.   
     
     
         2 . The vacuum cleaner of  claim 1 , further comprising a separating and collection assembly for separating and collecting liquid and/or debris from the working airstream for later disposal, the separating and collection assembly located on the upright unit. 
     
     
         3 . The vacuum cleaner of  claim 2  wherein the working air duct comprises a first working air duct between the nozzle unit and the separating and collection assembly and a second working air duct between the separating and collection assembly and the suction source. 
     
     
         4 . The vacuum cleaner of  claim 3  wherein the first working air duct and the second working air duct are at least one of flexible, pivotable, or have clearance for accommodating movement of the nozzle unit relative to the chassis. 
     
     
         5 . The vacuum cleaner of  claim 4  wherein the first working air duct and the second working air duct are both flexible hose segments. 
     
     
         6 . The vacuum cleaner of  claim 1  wherein the working air duct is at least one of flexible, pivotable, or has clearance to accommodate movement of the nozzle unit relative to the chassis. 
     
     
         7 . The vacuum cleaner of  claim 1  wherein at least a portion of the working air duct is adapted to compress and expand along a longitudinal axis of the portion of the working air duct. 
     
     
         8 . The vacuum cleaner of  claim 1  wherein the working air duct comprises a bellows-type construction. 
     
     
         9 . The vacuum cleaner of  claim 1  wherein a first portion of the working air duct and a second portion of the working air duct are coupled via a duct joint having one degree of freedom. 
     
     
         10 . The vacuum cleaner of  claim 1  wherein movement from a neutral operational position to a raised position of the nozzle unit rotates at least a portion of the working air duct. 
     
     
         11 . The vacuum cleaner of  claim 10  wherein the working air duct comprises an upright duct segment provided partially or entirely with the upright unit and a base duct segment provided partially or entirely with the base unit. 
     
     
         12 . The vacuum cleaner of  claim 10  wherein the at least a portion of the working air duct rotates rearwardly and compresses. 
     
     
         13 . The vacuum cleaner of  claim 1  wherein the nozzle unit further comprises an agitator provided adjacent to the suction nozzle for agitating debris on the surface to be cleaned. 
     
     
         14 . The vacuum cleaner of  claim 13  wherein the agitator comprises a rotatable brushroll, and the nozzle unit further comprises a motor operably coupled with the rotatable brushroll. 
     
     
         15 . The vacuum cleaner of  claim 1 , further comprising a pivot connection located between the upright unit and the base unit. 
     
     
         16 . The vacuum cleaner of  claim 15  wherein a portion of the working air duct extends through the pivot connection. 
     
     
         17 . The vacuum cleaner of  claim 1  wherein the predetermined force is greater than a weight of the nozzle unit. 
     
     
         18 . The vacuum cleaner of  claim 1  wherein the nozzle unit is moveable between two different raised operational positions, comprising:
 a first raised operational position, wherein the mechanical linkage is configured to automatically displace the suction nozzle toward the chassis to the first raised operational position upon a predetermined resistance force being applied to a forward side of the nozzle unit during a forward stroke of the vacuum cleaner across the surface to be cleaned; and 
 a second raised operational position, wherein the mechanical linkage is configured to automatically displace the suction nozzle away from the chassis to the second raised operational position upon a predetermined resistance force being applied to a rearward side of the nozzle unit during a rearward stroke of the vacuum cleaner across the surface to be cleaned. 
 
     
     
         19 . The vacuum cleaner of  claim 1  wherein the mechanical linkage comprises a cam joint that controls the position of the nozzle unit relative to the chassis and a pin-in-slot joint having two degrees of freedom and that limits the movement of the nozzle unit relative to the chassis. 
     
     
         20 . The vacuum cleaner of  claim 1  wherein the mechanical linkage comprises a rear link and a front link coupling the carriage with the nozzle unit in a loop with multiple joints.