in the preferred embodiment , squeegee assembly 10 is joined to machine 1 ( only the rear bottom corner of which is shown ) by means of coil spring 20 ( fig1 and 2 ). it is normally urged upwardly by a bias spring 50 . squeegee 10 can be forced downwardly through the action of pneumatic cylinder 40 on an arm 31 having a pressure pad 30 mounted on one end thereof . pressure pad 30 engages the top of squeegee assembly 10 in a slidable manner such that squeegee 10 is free to shift from side to side in spite of its engagement by pressure pad 30 . the entire squeegee assembly is supported on a caster support beam 3 which in turn is bolted to machine frame 2 ( fig1 and 3 ). casters 5 are also mounted on caster support beam 3 generally on either side of the squeegee support linkage . squeegee assembly 10 includes a wiper blade 11 and a clamp 12 which is used to clamp wiper blade 11 in place with the assistance of bolt assemblies 13 . ( fig1 and 4 ). this arrangement is generally conventional . the squeegee assembly 10 is generally v - shaped so that water is funneled to a vacuum port 14 generally at the center of squeegee 10 . protruding from the front of squeegee 10 is an integrally formed plug 16 which fits within a coupling 15 . coupling 15 is threaded such that coil spring 20 can be threaded thereto . a release pin 18 extends through coupling 15 and plug 16 to hold squeegee 10 in place . squeegee 10 can be removed by pulling pin 18 out and removing plug 16 from the interior of coupling 15 . positioned above plug 16 and extending laterally between both legs of the &# 34 ; v &# 34 ; formed by squeegee 10 is a rub plate 17 . it is rub plate 17 which is engaged by pressure pad 30 . coil spring 20 is a relative heavy spring having a diameter of approximately 13 / 4 &# 34 ;. the type of coil spring used in garage door mechanisms would suitably serve as coil spring 20 . coil spring 20 is threaded at one end over coupling 15 and at the other end over pivot mount coupling 21 . pivot mount coupling 21 is in turn mounted on a pivot axle 22 which extends between two downwardly projecting pivot brackets 4 ( fig1 - 3 ). pivot brackets 4 are in turn secured to caster support beam 3 and can advantagously be formed integrally with the main body of pneumatic cylinder 50 . through this pivotal mounting , coil spring 20 is free to pivot up or down about pivot axle 22 . coil spring 20 will of course exhibit a spring action in any direction in a plane extending laterally of the direction of travel of machine 1 . it will also expand somewhat in a fore and aft direction . as such , coil spring 20 provides an ideal mechanism and a most preferred mechanism for use in the present invention . however , it is conceivable that other spring means could be utilized , particularly if they exhibit at least a bending , side by side spring action . such an action allows the squeegee 10 to flex out of the way of a corner or other object when one side of it gets caught on that corner or other object . this bending action is definately enhanced by a coil spring wherein the coil spring would actually expand along one side if one edge of the squeegee 10 got hung up . pressure pad 30 is preferably made of a selflubricated plastic material . this causes it to slide more readily against rub plate 17 . an example of such a plastic material would be one of the nylons . pressure pad 30 is mounted on the base of a generally u - shaped arm 31 . each leg of arm 31 is in turn pivotally carried on pivot axle 22 ( fig3 ). in this way , arm 31 and pressure pad 30 can readily be pivoted upwardly or downwardly . this pivotal movement of u - shaped arm 31 is controlled by pneumatic cylinder 40 . the linkage is achieved through a generally u - shaped linking arm 32 having spaced downwardly depending legs and a cross piece 32a ( shown in fig1 and 2 , but not shown in fig3 so as to avoid complicating fig3 ). the end of each leg of arm 32 is pinned to one of the legs of arm 31 by link pin 33 . link pin 33 can be locked at various points within a slot 34 so that the relative elevation of arm 31 when cylinder 40 is not pressurized can be adjusted . the base 32a of linkage arm 32 is in turn joined to a pad 35 . pad 35 is in turn glued to the rubber diaphram 42 of cylinder 40 . cylinder 40 comprises a shallow inverted dish 41 . a generally dish shaped flexible rubber diaphram 42 is located within dish 41 and is held in place by means of a clamping ring 43 . clamping ring 43 is in turn held in place by clamping bolts 44 . when air under pressure is applied to cylinder 40 , flexible rubber diaphram 42 is pushed downwardly , thereby forcing arm 31 and squeegee 10 downwardly ( compare fig1 and 2 ). rubber diaphram 42 is of a relatively heavy rubber material . the rubber diaphrams employed in truck air brakes would be operable in the present invention . protruding from cylinder 40 is a pressure line coupling connector 45 ( fig3 ). air under pressure is fed from an air pressure source through a line 61 to connector 45 and from then into cylinder 40 . a pressure regulator 60 is located within line 61 so that a constance pressure can be maintained at cylinder 40 . regulator 60 ( shown schematically in fig3 ) is adjustable so that a relative agressiveness of squeegee 10 on the floor can be adjusted . bias spring 50 is a relatively light spring and need only be strong enough to hold squeegee 10 in an elevated position when there is no air under pressure within cylinder 40 . a screen door spring is satisfactory for this purpose . spring 50 is secured at each end to the rear edge flange of caster support beam 3 ( fig3 ). spring 50 then extends downwardly and passes under coil spring 20 at the point at which it is threaded onto coupling 15 . as squeegee 10 shifts from side to side , it simply slides along spring 50 . in operation , cleaning solution scrubbed onto the floor at the front of machine 1 is funneled inwardly towards vacuum port 14 by the generally v - shaped wiper blade 11 of squeegee 10 . the liquid is then drawn up through vacuum port 14 and through a conduit to a recovery tank mounted on machine 1 . air is supplied to cylinder 40 through a pressure regulator 60 ( fig3 ) such that the pressure within cylinder 40 is always constant . this insures that squeegee 10 will exert a constant pressure against the floor being cleaned regardless of deviations in the floor . by adjusting pressure regulator 60 , one can adjust the relative agressiveness of squeegee 10 on the floor . as one turns machine 1 around a corner , the frictional engagement of wiper blade 11 on the floor will tend to cause squeegee 10 to want to take the shortest possible path around the corner . coil spring 20 will flex to one side as rub plate 17 slides beneath pressure pad 30 , thereby allowing squeegee 10 to do so . this constitutes the proper path for squeegee 10 to follow in order to maximize the recovery of cleaning solution being laid down by machine 1 . if squeegee 10 catches on a corner or other protruding objects , coil spring 20 will bendably flex to one side thereby allowing squeegee 10 to slide past the object without causing excessive damage to it . when it is desired to raise squeegee 10 , one merely exhausts pressure from the line to cylinder 40 , thereby causing biasing spring 50 to raise squeegee 10 . of course , it is understood that the above is merely a preferred embodiment of the invention and that various changes and alterations can be made without departing from the spirit and broader aspects thereof as set forth in the appended claims which are to be interpretted in accordance with accepted principles of patent law .