Abstract:
A portable surface cleaning apparatus has a base for movement along a surface to be cleaned and an upright handle pivotally attached to a rearward portion of the base. A fluid dispensing nozzle for applying fluid to the surface and a suction nozzle for picking up fluid and debris from the surface are associated with the base. A clean water holding tank and a detergent holding tank are removably mounted to the handle while a recovery tank is removably mounted to the base. A mixing valve is fluidly connected between the holding tanks and the spray nozzle for changing the mixing ratio of the detergent with respect to the water. The fluid recovery tank includes an integrally molded conduit that extends from the suction nozzle and a mounting for an accessory hose that interrupts the fluid path from the suction nozzle in the conduit and redirects fluid flow through the hose. A pump is fluidly connected between the mixing valve and the dispensing nozzle and includes a pump priming valve that operates on negative air pressure to clear air from the fluid lines during pump operation. A free floating brush is pivotally attached to the base for automatically adjusting to different surface conditions during cleaning operations.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation application of U.S. patent application Ser. No. 09/009,155, filed Jan. 20, 1998, now U.S. Pat. No. 6,041,472, which is a continuation-in-part of U.S. patent application Ser. No. 08/741,746 filed on Nov. 5, 1996 now U.S. Pat. No. 5,896,617, which claims the benefit of U.S. Provisional Application Nos. 60/007,289 filed on Nov. 6, 1995; 60/006,665 filed on Nov. 13, 1995; 60/017,175 filed on May 9, 1996; and 60/026,988 filed on Sep. 20, 1996. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to cleaning machines and, more particularly, to an upright water extraction cleaning machine. 
     2. Description of the Related Art 
     Water extraction clearing machines have long been used for removing dirt from surfaces such as carpeting, upholstery, drapes, and the like. The known water extraction cleaning machines can be in the form of a canister-type unit as disclosed in U.S. Pat. No. 5,237,720 to Blase et al. or an upright unit as disclosed in U.S. Pat. No. 5,500,977 to McAllise et al. and U.S. Pat. No. 4,559,665 to Fitzwater. 
     The current water extraction cleaners can be difficult to use and often have limited adaptability for a variety of cleaning conditions. For example, none of the known water extraction cleaners can quickly and efficiently vary the mixture ratio of detergent and water. In addition, none of the known upright water extraction cleaners can automatically adjust the height of the roller-type agitation brush in response to changes on the surface being cleaned. Another problem inherent with the known water extraction cleaners is ease of use in filling and emptying the clean water tank and recovery tank. Finally, none of the known prior art water extraction cleaners can quickly and easily convert between on-the-floor cleaning and off-the-floor cleaning with an accessory hose and cleaning tool. 
     SUMMARY OF THE INVENTION 
     According the invention, a recovery tank adapted for attachment to the base of a portable surface cleaning apparatus comprises an upper wall, a lower wall and at least one side wall connected together to define an enclosed chamber. The upper wall has an enclosed channel defining a conduit and an opening extending from the conduit into the chamber. The conduit is in fluid communication between a suction nozzle and a vacuum source of the cleaning apparatus when the recovery tank is attached to the base to thereby draw liquid and debris from a surface and deposit the liquid and debris into the recovery tank. A baffle is attached to an inner surface of the upper wall adjacent the upper wall opening. The baffle extends into the inner chamber from the upper wall to thereby separate fluid and debris from the air during cleaning operations. 
     According to a further embodiment of the invention, a recovery tank is adapted for attachment to the base of a portable surface cleaning apparatus having a handle attached to the base and a suction nozzle adapted for fluid communication with the recovery tank and a vacuum source. The recovery tank comprises an upper wall, a lower wall and at least one side wall connected together to define an enclosed chamber for holding a predetermined level of recovered liquid from a surface being cleaned. A first opening is formed in one of the recovery tank walls above the predetermined level for fluid communication between the recovery tank and the suction nozzle. A second opening is formed in one of the walls of the recovery tank below the predetermined level for fluid communication between the recovery tank and the vacuum source. An exhaust stand pipe has a lower end attached to an inner surface of the recovery tank. The stand pipe lower end surrounds the second opening while an upper free end of the exhaust pipe extends above the predetermined level. With this arrangement, liquid at or below the predetermined level in the recovery tank is at least substantially prevented from entering the second opening and traveling to the vacuum source when the recovery tank is mounted on the base. 
     An elongate float has a first end that is buoyant and a second end that is adapted to cover the upper free end of the stand pipe when liquid in the recovery tank reaches the predetermined level to thereby block the transfer of air and liquid from the recovery tank to the vacuum source. Preferably, at least one guide wall extends from the lower wall adjacent the stand pipe and the first buoyant end of the float is located between the stand pipe and the guide wall for guiding movement of the float second end toward the stand pipe upper free end during liquid rise in the recovery tank. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be described with reference to the drawings in which: 
     FIG. 1 is a front, perspective view of an upright water extraction cleaning machine according to the invention; 
     FIG. 2 is a rear, perspective view of the upright water extraction cleaning machine of FIG. 1; 
     FIG. 3 is a partial, side-elevational view showing a pivot mounting and locking arrangement of the upper housing to the base according to a first embodiment; 
     FIG. 3A is an enlarged side-elevational view shown in area A of FIG. 3 with the upper housing tilted with respect to the base; 
     FIG. 3B is a view similar to FIG. 3 showing a pivot mounting and locking arrangement according to a second embodiment; 
     FIG. 4 is a schematic view showing the cleaning fluid distribution system of the cleaning machine of FIG. 1; 
     FIG. 5 is a partial, sectional, exploded view of the tank assembly and handle; 
     FIG. 6 is a partial, sectional, exploded view of the tank one-way valve and tank seat assembly; 
     FIG. 7 is a partial sectional view of the variable fluid mixing valve mechanism shown in a first position; 
     FIG. 8 is a partial sectional view of the variable fluid mixing valve of FIG. 7 shown in a second position; 
     FIG. 9 is a partial, sectional view of the foot member and recovery tank taken along lines  9 — 9  of FIG. 1; 
     FIG. 10 is an exploded view of the recovery tank assembly; 
     FIG. 11 is a front perspective view of the upright water extraction cleaning machine of FIG. 1 showing the accessory hose mounted in the operative position; 
     FIG. 12 is a partial, sectional view showing the mounting of the accessory hose to the recovery tank; 
     FIG. 13 is a partial, exploded view of the agitation brush assembly and foot member; and 
     FIG. 14 is a perspective view of an alternative embodiment of the agitation brush of FIG.  13 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the drawings and to FIGS. 1 and 2, in particular, an upright water extraction cleaning machine  12  is shown which comprises a base assembly  14 , an upper housing  16  pivotally mounted to the base assembly  14 , a handle  18  extending upwardly from the upper housing  16 , and a tank assembly  20  mounted to and supported by both the handle  18  and upper housing  16 . 
     The base assembly  14  comprises a foot or base member  24 , a pair of rear wheels  26 ,  28  mounted to the rear of the foot member  24 , and a recovery tank  30  removably supported on the foot member  24 . A pair of over-center latches  32  are provided, one on each side of the foot member  24 , and are adapted to cooperate with a pair of projections  34  (FIG.  10 ), one provided on each side of the recovery tank sidewall for locking the recovery tank  30  to the foot member  24 . A handle  36  is pivotally mounted to the recovery tank  30  for carrying the tank. As shown in FIGS. 1,  2  and  10 , the handle  36  is generally U-shaped and is pivotably mounted at an upper portion of the tank in a recessed area between the tank top wall and sidewall. The sides of the handle nest within the recessed area between the top wall and the side wall when the handle is in the stored position as illustrated in FIGS. 1 and 2. 
     As described further below, the tank assembly  20  comprises a clean water tank  42  and a detergent tank  44  which nests inside the front surface of the clean water tank  42 . A pair of over-center latches  46  are provided, one on each side of the sidewall of the upper housing  16 . The latches  46  are adapted to cooperate with a pair of projections  48  (FIG.  5 ), one of which is provided on each of the sidewalls of the clean water tank  42 , for locking the tank assembly  20  to the upper housing  16  and handle  18 . 
     An accessory hose storage rack  50  is mounted to the rear surfaces of the handle  18  and upper housing  16 . The rack  50  includes an upper portion  51  and a lower portion  53  and is adapted to support and store an accessory hose  52  when the hose is not in use. An accessory hose mounting member  62  is mounted on one end of the hose  52  and is received in a C-shaped clip  66  provided on the upper end of the rack  50 . The flexible body of the hose  52  is wrapped around the upper and lower portions  51 ,  53  of the storage rack  50 . A grip tube  64  is mounted on the other end of the hose  52  and is snapped into the C-shaped clip  66  integrally molded into the rack  50 . In this position, the entire length of the accessory hose  52  is supported on the rack  50  and is easily transported with and stored on the cleaning machine  12 . Preferably, the accessory hose  52  remains on the rack at all times, except when the hose  52  is in use. A double C-shaped clip  67  (FIG. 2) can be provided at one or more locations to clamp adjacent portions of the hose  52  together when the hose is stored on the machine. The double C-shaped clip  67  can be removed from the hose when the hose is unwrapped for use. 
     The grip tube  64  of the accessory hose  52  is adapted to receive cleaning tools such as the upholstery tool  68  shown in FIGS. 1 and 2. However, any number of a variety of cleaning tools can be received on the grip tube  64  such as a crevice spray tool as seen in U.S. patent application Ser. No. 08/574,769 which is expressly incorporated herein by reference or, alternatively, a window washing tool as seen in U.S. patent application Ser. No. 08/683,608 which is also expressly incorporated herein by reference. 
     A closed loop grip  58  is provided at the terminal end of the handle  18  and a trigger  60  is pivotally mounted to the handle  18  inside the closed loop grip  58 . As described further below, the trigger  60  is used to control the distribution of cleaning solution from the base assembly  14 . 
     A releasable latch  40  is mounted to the base assembly  14  and is adapted to retain the handle  18  and upper housing  16  in the upright, stored position as seen in FIGS. 1 and 2. The handle  18  can be tilted rearwardly by grasping the handle  18  and depressing the latch  40  relative to the base assembly  14 . With the latch  40  depressed, the handle is then tilted rearwardly with respect to the base assembly  14 . 
     A three-position electrical switch  54  is mounted to the rear of the handle  18 . The three positions of the switch are as follows: (a) all systems off, (b) the “pre-treat” position in which both the cleaning solution pump and agitation brush are on but the vacuum motor is turned off, and (c) the “cleaning position” in which the vacuum motor, agitation brush, and cleaning solution pump are all on. 
     An electrical cord  56  extends outwardly from the upper housing  16  and is electrically connected to the three-position switch  54 . A pair of opposed cord wraps  70 ,  72  are provided on the upper and lower portions  51 ,  53  of the storage rack  50  for containing the electrical cord  56  when the machine  12  is not in use. 
     A large number of the operative components of the machine  12  are mounted to or provided inside the upper housing  16  and handle  18 . As noted previously, the tank assembly  20  is supported on the handle  18  and upper housing  16 . A vacuum motor  74  and impeller fan  76  are mounted in the round, bulbous lower portion of the upper housing  16 . The upper portion of the upper housing supports a large number of components of the water distribution system such as the solution pump mixing valve which will be described in greater detail, below. 
     FIG. 3 shows the pivot mounting and locking assembly of the upper housing  16  to the base assembly  14 . In this side-elevational view, the wheel  26  is shown in phantom lines to reveal the pivot mounting and locking assembly of these two elements. The pivot mounting itself is identical for both the right and left sides of the upper housing  16 , and therefore, only the left side will be described in detail. 
     The foot or base member  24  includes an upwardly extending rear support member  80  with a semi-circular bearing surface  82  integrally formed therein. A substantially circular boss  84  extends outwardly from the sidewall  86  of the upper housing  16  and is adapted to be received in the bearing surface  82 . A retention member  88  having an integrally molded substantially semi-circular bearing surface  90  formed therein is adapted to be secured to the top surface of the support member  80 , thereby capturing the outwardly extending boss  84  of the upper housing  16  between the opposed semi-circular bearing surfaces  82 ,  90 . The a projection  92  formed on the retention member  88  fits within a groove of the foot member  24 . The rear portion  89  of the retention member can be secured to the foot member  24  through a screw-type fastener  91  passing through the projection  92  and into the foot member  24 . A front portion  96  of the retention member  88  has a pair of tabs  102  (only one of which is shown) extending downwardly therefrom. A free end of each tab  102  includes a barb  104  that snaps within a corresponding groove (not shown) in the foot member  24  to secure the front portion  96  of the retention member  88  to the foot  24 . 
     Referring now to FIGS. 3 and 3A, a locking assembly  105  is preferably located on the left side of the cleaning machine  12 , although it is to be understood that the locking mechanism can alternatively or in addition be arranged on the right side. The locking assembly  105  includes a foot engagement section  107  and a stem  109  formed integrally with the foot engagement section  107 . A pivot pin  101  extends through a tab  111  on the retention member  88  and the stem  109  to pivotally attach the foot engagement section  107  to the base member  24 . A flat spring  113  is integrally formed with the stem  109  with a free end  127  thereof abutting an upper surface of the retention member rear portion  89 . The spring  1   13  biases the foot engagement section  107  toward the front portion  96 . A locking extension  115  includes a flat locking surface  117  and a bearing surface  119 . The base member  24  includes a semi-cylindrical laterally extending protrusion  125  which is located on the side wall  86  with a flat locking surface  121  and a curved bearing surface  123 . 
     In the normally upright position, as shown in FIG. 3, the flat locking surfaces  117 ,  121  abut each other or are in close proximity to each other. If a user attempts to rotate the handle  18  with respect to the foot member  24 , the locking surfaces  117 ,  121  engage and prevent relative rotation of the handle and foot member. When the foot engagement portion  107  is depressed, as shown in phantom line, the locking extension  115  rotates away from the protrusion  125  until the locking surfaces are no longer in facing relationship. In this position, the handle  18  can be rotated with respect to the base member  24 . When the handle is rotated to the upright position, the bearing surface  119  engages the bearing surface  123  to rotate the foot engagement portion  107  against the bias of spring  113  until the locking extension  115  is clear of the protrusion  125  and the locking surfaces  117 ,  121  are again in facing relationship. 
     As described further below in relation to FIG. 9, the preferred embodiment of the cleaning machine  12  incorporates a rotatably mounted agitation brush which receives the force of rotation from a brush motor mounted to the foot member  24 . In any position other than the off position for the switch  54 , electrical current is supplied to the brush motor for rotating the agitation brush. However, when the accessory hose  52  is being utilized, or when the handle  18  is merely in the upright position and the switch is in either the pre-treat or cleaning position, it is undesirable to permit continued rotation of the agitation brush. Therefore, an interrupt switch  98  is provided in the electrical circuit between the brush motor and the source of electricity. The switch  98  is mounted to the foot member  24  and adapted to cooperate with a projection  100  extending outwardly from the front, bottom surface of the upper housing  16 . In the position as shown in FIG. 3, the projection  100  bears against the switch  98 , thereby opening the electrical circuit between the source of electricity and the agitation brush. Therefore, the brush will not rotate, regardless of the position of the three-position switch  54 . Upon rearward titling movement of the handle  18  and upper housing  16  relative to the base assembly  14 , the projection  100  will pivot out of contact with the interrupt switch  98  mounted on the foot member  24 . Once the projection  100  has moved out of contact with the switch  98 , then the switch  98  will assume a closed position and complete the circuit between the source of electricity and the brush motor, assuming that the three-position electrical switch  54  is in any position other than off. Alternatively, the relative position of the switch and projection can be reversed so that the switch is mounted on the upper housing and selectively contacts a projection mounted on the foot member  24 . Instead of the projection  100 , a spring and biased pin can be mounted to the upper housing or foot member  24  in order to provide additional travel for actuating the switch  98 . When the pin is mounted to the foot member, the switch is preferably mounted to the upper housing. 
     In an alternative arrangement, the switch  98  can be replaced by an ON/OFF switch that is mounted at a convenient location on the cleaning machine  12  for actuation by a user. 
     With the upper housing  16  and handle  18  pivotally mounted to the base assembly  14 , the water extraction cleaning machine can be used in a manner similar to an upright vacuum cleaning machine. In other words, the operator can grasp the closed loop grip  58  and manipulate the base assembly  14  forward and backward over the surface being cleaned. 
     With reference now to FIG. 3B, a pivot mounting and locking assembly  105 ′ according to a second embodiment is illustrated, wherein like parts in the previous embodiment are represented by like numerals. As with the assembly  105 , the assembly  105 ′ is preferably located on the left side of the cleaning machine  12 , although it is to be understood that the locking mechanism can alternatively or in addition be arranged on the right side. The locking assembly  105 ′ includes a foot engagement section  107 ′ and a stem  109 ′ formed integrally with the foot engagement section  107 ′. As in the previous embodiment, a pivot pin  101  extends through a tab  111  on the retention member  88  and the stem  109 ′ to pivotally attach the foot engagement section  107 ′ to the base member  24 . A flat spring  113 ′ is integrally formed with the stem  109 ′ with a free end  127 ′ thereof abutting an upper surface of the retention member rear portion  89 . The spring  113 ′ biases the foot engagement section  107 ′ toward the front portion  96 . A lever arm  115 ′ is integrally molded with, or otherwise rigidly attached to the stem  109 ′ and extends outwardly and downwardly therefrom. A pin  155  projects from the outer free end  157  of the lever arm  115 ′ and rides in a slot  159  of a locking plate  161 . The locking plate  161  is pivotally attached to the base member  24  through a pivot pin  163  and includes a hook-shaped locking portion  165  with an inner hook surface  169 . The base member  24  includes a cylindrical laterally extending protrusion  125 ′ which is located on the side wall  86 . 
     In the normally upright position, as shown in FIG. 3B, the inner hook surface contacts an outer surface of the protrusion  125 ′ to prevent relative rotation of the handle and foot member. When the foot engagement portion  107 ′ is depressed, as shown in phantom line, the pin  155  rides in the slot  159  of the locking plate  161  and forces the locking plate to pivot in a direction opposite to the pivoting direction of the foot engagement portion  107 ′. The hook-shaped locking portion  165  rotates away from the protrusion  125 ′ until it is clear of the protrusion. In this position, the handle  18  can be rotated with respect to the base member  24 . The locking plate then rotates to its original position under bias from the spring  113 ′. When the handle is rotated to the upright position, the inner surface  169  catches the protrusion  125 ′ and forces the plate (and foot engagement portion) to rotate against the bias of the spring  113 ′ until the protrusion  125 ′ is seated in the hook-shaped locking portion  165 . 
     FIG. 4 is a schematic representation of the cleaning solution distribution system for the preferred embodiment of the cleaning machine. Generally, clean water and detergent are drawn from the respective tanks  42 ,  44  to a mixing valve  110  through the operation of a pump  112 . The pump  112  then conducts the pressurized cleaning solution to spray nozzles  114  provided on the base assembly  14  or to the trigger valve  108  of the accessory hose  52  through an accessory hose solution tube mounting  116  provided on the front wall of the upper housing  16  and an accessory hose tube connector  106  mounted on the end of the hose  52  opposite the cleaning tool  68 . 
     Turning now to the specific structure of the cleaning solution distribution system, as seen in FIGS. 4-6, both the clean water tank  42  and the detergent tank  44  include one-way valve mechanisms  122  on the bottom surfaces thereof which cooperate with tank seat assemblies  150  provided on the upper surface of the upper housing  16  to control the flow of fluid from the tank to the other components of the distribution system. The structure of the one-way valves  122  and tank seat assemblies  150  is identical, and therefore, only the structure of the clean tank valve  122  and seat assembly  150  will be described in detail. 
     The bottom wall of the clean tank  42  has a downwardly extending threaded boss  118  with an aperture extending therethrough. A threaded cap  120  is rotatably received on the boss  118 , and mounts a one-way valve member  122  enclosing the aperture of the boss. The valve member  122  comprises a hollow valve body  124  having a downwardly extending connector boss  126  with a fluid flow aperture  128  extending therethrough. A flexible rubber seal  130  fits around the boss  126  and is adapted to engage an inner surface  151  of the tank seat assembly  150  when the valve member is installed thereon. A gasket  132 , a release rod or plunger  138  and a compression spring  136  are located within the valve body  124  and held in position by a spring housing  134 . A lower end of the spring housing  134  can be securely attached to the inside of the hollow valve body through ultrasonic welding, adhesives, or other well known means. The spring housing  134  preferably has a plurality of apertures  144  to permit the flow of fluid from the tank therethrough. A screen  146  is attached to an upper end  148  of the spring housing  134  to filter out large particles of foreign material that may be present in the fluid. An outer shoulder  145  on the valve body receives an annular gasket  147  that seals around the lower edge of the boss  118  of each tank. 
     The release rod  138  has an annular flange  140  that seats against the gasket  132  under a biasing force from the spring  136  to prevent the flow of fluid from the tank when it is separated from the tank seat assembly  150 . Preferably, the bottom of the release rod  158  is flush with the bottom of the connector boss  126 , or slightly thereabove to prevent inadvertent valve opening when the tank is placed right side up on a surface. 
     The tank seat assembly  150  comprises a seat member  152  having a substantially circular flange  154  extending upwardly and downwardly from a base plate  156 . A central projection  158  extends upwardly from the base plate  156 , and a plurality of fluid apertures  160  are formed in the base plate  156  intermediate the central projection  158  and the circular flange  154 . A reservoir  162  is mounted to the seat member  152  beneath the fluid apertures  160 , and a conventional hose mounting  164  extends outwardly from the reservoir  162 . A conventional hose  166  is mounted to the hose mounting  164  and fluidly connects the reservoir to the mixing valve  110  which is then fluidly connected to the pump  112 . 
     The preferred embodiment of the seat assembly  150  also includes a one-way umbrella valve  167  to prevent the back flow of solution from the reservoir  162  past the base plate  156 , which may occur when the liquid level in one supply tank is higher than the liquid level in the other supply tank. The one-way valve comprises an elastomeric umbrella valve member  168  having a central stem  170  extending from one side thereof which is received in an appropriate aperture  172  of a support disc  174 . The disc  174  is supported in a suitable recess  176  provided in the seat member  152 . The disc  174  has a plurality of flow apertures  178  provided therein, all of which are adapted to be covered by the umbrella valve  168 . When either positive fluid pressure is exerted on to the top surface of the umbrella valve  168 , or negative fluid pressure is created in the reservoir  162  positioned beneath the valve member  168 , then the outer radius of the body of the umbrella valve  168  will deflect downwardly to permit the flow of fluid from the seat member  152  to the reservoir  162 . 
     As described further below, the tanks are received on the handle  18  and upper housing  16  by vertical movement of the tank assembly  20  with respect to the upper housing  16 . Eventually, the one-way valves  122  of the tanks will be telescopically received inside the tank seat assemblies  150  so that the central projection  158  extends upwardly through the boss  126  of the one-way valve a sufficient distance to dislodge the rod  138  from the aperture  128 , thereby permitting the flow of fluid through the one-way valve and into the tank seat assembly  150 . When the tank is lifted vertically with respect to the upper housing  16 , the central projection  158  will be telescopically removed from the aperture  128 , and the spring  136  will bias the rod  138  of the one-way valve back into sealing position to prevent the inadvertent flow of fluid through the one-way valve. 
     The tank assembly  20  is configured for easy refilling of the tanks and securing the tanks to the upper housing  16  and handle  18 . The clean water tank  42  has an integrally molded carrying handle  184  and a cap  186  closing a fill opening aperture  188  formed on the top wall of the tank. A protrusion  187  is integrally molded with the bottom of the clean water tank and fits within a corresponding depression (not shown) in the upper housing  16 . The outer wall of the protrusion facilitates alignment of the tank assembly  20  with the upper housing  16 . The inner volume of the protrusion can be filled with detergent that will be mixed in a predetermined ratio when the tank  42  is subsequently filled with water, in the event that the detergent tank  44  and mixing valve are not used. The cap  186  can be quickly and easily removed for filling the tank  42  with clean water. 
     As noted above, the clean water is discharged through the boss  126  and one-way valve mechanism  122  provided on the bottom wall of the clean water tank  42 . A vent opening  182  extends through the upper wall of the tank  42  to allow entry of air when water is removed from the tank from the valve mechanism  122 . If the plunger  138  becomes stuck during operation, the vent opening  182  prevents siphoning if liquid should leak past the plunger. 
     The detergent tank  44  nests into a recess  190  accessible through the front wall  192  of the clean water tank  42 . Preferably, the recess  190  is formed in the front, bottom edge of the clean water tank and is defined by a pair of opposed sidewalls  194 , a rear wall  196 , and a top wall  198 . A pair of substantially horizontal projections  200  are provided on the sidewalls  194  of the recess  190 . These projections  200  are adapted to cooperate with a pair of substantially complimentary grooves  202  formed in the sidewalls  204  of the detergent tank  44  for mounting the tanks to one another. The detergent tank  44  is removed from the clean water tank  42  by sliding the detergent tank  44  forward, parallel to the axis of the projections  200  and grooves  202 , until the detergent tank  44  is removed from the recess  190 . 
     The detergent tank  44  must be refilled by unscrewing the cap  120  of the one-way valve assembly and removing the valve member  122  to permit refilling of the tank  44  through the boss aperture. The detergent tank  44  has an umbrella valve  203  (FIG. 5) that fits within a venting aperture  205  on the tank  44  to prevent fluid leakage when the tank is inverted for refilling. The umbrella valve  203  is preferably similar in construction to the one-way umbrella valve  167  in FIG.  6 . Once the tank  44  has been refilled, the one-way valve member  122  and cap  120  are replaced, the tank  44  is inverted, and then slid into the recess  190  of the clean water tank  42 . 
     As noted briefly above, the tank assembly  20  is preferably slidably mounted to the handle  18 . The rear wall of the clean water tank  42  includes a U-shaped groove  210  which is substantially complementary to the front portion of the handle  18 . The groove  210  is defined by a pair of opposed sidewalls  212  and a front wall  214 . The sidewalls  212  include a pair of linear grooves  216  which are complementary to a pair of linear projections  218  formed on sidewalls  220  of the handle  18 . The handle projections  218  extend only a portion of the length of the handle  18 . The tank assembly  20  is slidably received on the handle  18  by positioning the tank assembly  20  vertically above the upper housing  16  so that the projections  218  and grooves  216  are aligned with one another. Then the tank assembly  20  is lowered so that the tank assembly  20  is slidably received on the handle  18  and the grooves  216  receive the projections  218 . The tank assembly  20  is fully received on the handle  18  when the one-way valve assemblies of the tanks  20  engage the seat assemblies  150  provided on the top wall of the upper housing  16 . The tank seat assemblies  150  are not rigidly mounted horizontally in order to allow alignment of the two tank outlets, which would otherwise cause leaks. Once the tank assembly is in this position, the latches  46  can then be pivoted onto the projections  48  for locking the tank assembly  20  to the handle  18  and upper housing  16 . 
     Returning to the solution flow schematic diagram seen in FIG. 4, the mixing valve  110  is positioned intermediate the tank seat assemblies  150  and the solution pump  112 . Preferably, the mixing valve is a variable mixing valve  110  to accommodate differing mixtures of detergent and clean water. As seen in FIGS. 4,  7 , and  8 , the variable mixing valve  110  comprises a valve body  230  having a clean water inlet  232  which is fluidly connected to the clean water tank seat assembly  150  by the hose  166  and a detergent inlet  236  which is fluidly connected to the detergent tank seat assembly  150  by a hose  238 . A solution outlet  240  is also formed on the valve body  230  and is adapted to conduct the clean water and detergent mixture from the mixing valve  110  to the pump  112  through a hose  242 . 
     The valve body is formed from an end cap  244 , a central body portion  246 , and an end inlet member  248  mounted to the end of the central body portion  246  opposite the end cap  244 . A plunger  250  extends through an aperture in the end cap  244  such that a shaft  251  of the plunger  250  is received inside the central body portion  246  and the end inlet member  248  and a portion of the shaft extends outwardly from the end cap  244 . A cam follower  252  is formed at the outer end of the shaft  251  and is adapted to ride along a contoured cam surface  272  of a cam  270 , as seen in FIG. 7. A plunger head includes a collar  254  that is positioned along the length of the shaft of the plunger  250  and has an annular groove  256  formed therein that receives an O-ring  258 . The collar  254  and O-ring  258  are adapted to create a fluid seal inside the circular valve body and in cooperation with the central body portion define a mixing chamber  260  therein. An O-ring  262  is provided in the central body portion  246  immediately adjacent the end inlet member  248 . The O-ring  262  cooperates with the plunger  250  to effectively seal the end inlet member  248  and detergent inlet  236  from the mixing chamber  260 , depending upon the axial position of the plunger  250  within the valve body  230 . 
     The plunger  250  forms a valve stem  263  at one end with a tapered groove  264  which extends along the surface of the plunger valve stem  250 , preferably passing through the end wall of the plunger  250 , and is tapered so that the groove  264  has a greater cross-sectional area immediately adjacent the end than it does a spaced distance therefrom. The valve stem  263  is positioned in the detergent inlet  236  opening to control the flow of detergent therethrough. The purpose of the tapered groove  264  is to accommodate varying flow rates of detergent through the opening in the detergent inlet  236  into the mixing chamber  260  of the valve body  230 . 
     A control knob  266  is mounted on the front wall  268  of the upper housing  16  for controlling the water/detergent ratio in the cleaning solution delivered to the pump  112 . The cam  270  is mounted to the rear surface of the knob  266 , and the cam  270  is positioned so that the terminal end of the plunger  250  bears against the contoured surface  272  of the cam  270 . FIGS. 7 and 8 depict the two extreme ranges of solution mixtures in the preferred embodiment of the cleaning machine  12 . FIG. 7 shows the plunger  250  extended outwardly from the valve body  230  the maximum distance. In this position, the maximum length of the tapered groove  264  is extended into the mixing chamber  260  of the valve. Therefore, the maximum amount of detergent will be drawn into the mixing chamber  260  and ultimately discharged to the pump  112 . 
     FIG. 8 depicts the other extreme position in which the plunger  250  is positioned so that the entire length of the tapered groove  264  is withdrawn from the mixing chamber  260  so that there is no fluid flow communication between the detergent inlet  236  and the mixing chamber  260 . Therefore, only clean water will be directed to the pump  112 . As is evident, the contoured surface  272  of the cam  270  permits an infinite number of detergent to water mixing ratios between the two extremes shown in FIGS. 7 and 8. In the preferred embodiment, the knob  266  and cam  270  are received in only one of three positions, the water only or “rinse” position as seen in FIG. 8, a maximum detergent to water mixing ratio as seen in FIG. 7, or a standard mixing ratio half-way between the extremes shown in FIGS. 7 and 8. In use, the knob  266  is intended to be positioned at the standard mixing ratio position for the vast majority of cleaning operations. When a high traffic or heavily stained area is encountered, the knob  266  can be rotated to the maximum detergent position as seen in FIG.  7 . If a final clean water rinsing operation is desired, then the knob  266  can be rotated to the water only position as seen in FIG.  8 . The incorporation of the variable mixing valve  110  permits varying the water/detergent mixture ratios to accommodate a wide variety of cleaning situations. 
     With reference again to FIG. 4, and as noted above, the pump  112  is positioned downstream from the variable mixing valve  110 . When the pump  112  is energized and primed, the pump  112  will draw fluid from the mixing valve  110  and tank seat assemblies  150  at the prescribed ratio. Although different pump types can be used, the pump  112  preferably does not self-prime. Some means, therefore, should be incorporated to assist priming of the pump  112 . The fluid flow system in FIG. 4 includes a pump priming valve  280  which is preferably mounted vertically above the pump  112 , the tank seat assemblies  150  in the base of the handle  18 , and the water level in the tank  42 . The pump priming valve  280  includes an inlet port  282  that is fluidly connected to the outlet of the pump  112  and a fluid outlet port  284  that is fluidly connected to the impeller fan chamber of the vacuum motor  74  (FIG.  2 ), or a portion of the recovery tank that is exposed to vacuum pressure. The pump priming valve  280  comprises a hollow valve body having an inner chamber  286 . Preferably, a small shoulder  292  with a central aperture  294  is formed inside the valve body. An elongate plunger  290  having a conical rubber sealing tip  296  is received for reciprocal movement inside the ball chamber. The priming valve  280  may also include a vent aperture (not shown) to prevent potential siphoning. 
     In operation, the pump  112  will be primed with the fluid from the solution tanks by turning the pump  112  on and the vacuum motor  74  on. The vacuum motor  74  will exert negative pressure on the fluid outlet of the pump  112  through the pump priming valve  280  thereby drawing any air out of the pumping chamber (not shown) between the pump inlets and the solution tanks therethrough. The air will be drawn through the pump priming valve  280  into the vacuum impeller fan chamber or into the recovery tank  30 . Preferably, the weight and dimensions of the plunger  290  is coordinated with the amount of negative air pressure applied to the pump priming system from the vacuum motor so that the negative air pressure applied to the fluid chamber  286  is insufficient, by itself, to draw the plunger  290  upwardly and seal the outlet of the pump priming valve. 
     As the vacuum motor  74  operates to draw the air from the system, it is likely that some fluid will enter the pump priming valve  280 . Preferably, the size of the elongated fluid chamber  286  is dimensioned to accommodate a sufficient amount of fluid to permit full priming of the pump  112 . Eventually, the fluid level will rise inside the pump priming valve  280  and fluid will enter the ball chamber  286 . The plunger  290  is preferably formed of a material and dimension such that the fluid alone does not cause the plunger to rise in the chamber. However, the combined pulling force from the negative air pressure and the pushing force from the rising liquid inside the chamber acting on the plunger causes the plunger to rise until the sealing tip  296  bears against the shoulder  292  and seals the aperture  294  to prevent solution from flowing therefrom. Once this seal has established, the pump should be sufficiently primed for normal operation. 
     Following the pump priming valve  280 , the pressurized solution is simultaneously directed to the accessory hose solution tube mounting  116  and a conventional trigger valve  300 . As seen in FIGS. 4 and 5, the trigger valve  300  is positioned in the base of the handle  18  immediately below the bottom end of an actuator rod  302 . The rod  302  extends upwardly to pivotally interconnect with the trigger  60  provided in the closed loop grip  58  of the handle  18 . In the preferred embodiments, multiple actuator rods  302  are interconnected to traverse the distance between the trigger  60  and the trigger valve  300 . 
     Upon squeezing of the trigger  60  relative to the closed loop grip  58 , the actuator rods  302  are displaced downwardly to squeeze the plunger  304  of the conventional trigger valve  300  and permit the flow of fluid therethrough. With the trigger valve  300  in the open position, pressurized fluid flows through a conventional conduit  306  to a pair of spray tips  114  mounted to the foot member  24  immediately adjacent the agitation brush. Preferably, the spray tips  114  are adapted to create a fan-shaped spray pattern which traverses substantially the entire width of the agitation brush and suction nozzle opening. Turning now to the fluid recovery system, the vacuum motor  74  and impeller fan  76  generate negative air pressure which is communicated from the upper housing  16  to the base assembly  14  for recovery of used solution and dirt. As shown in FIGS. 9 and 10, the working air flow path for on-the-floor cleaning begins at the suction nozzle opening  316  provided at the front, forward edge of the base assembly  14 . Preferably, the suction nozzle opening is defined by a front plate member  318  and a rear plate member  320  which are mounted to one another and which also define the initial working air flow conduit  322 . The suction nozzle opening  316  extends the entire width of the base assembly  14  and the plate members  318 ,  320 . A pair of sidewalls  324  are integrally formed into the rear plate member to define the sides of the initial flow conduit. Preferably, the sidewalls  324  taper upwardly and inwardly (see FIG.  1 ). The initial flow conduit  322  terminates at an outlet  326  positioned along the top edges of the plate members and sidewalls. In view of the fact that the sidewalls of the flow conduit taper upwardly and inwardly, the length of the outlet of the initial suction flow conduit is less than the length of the suction nozzle opening and the width of the base assembly  14 . Preferably, an elastomeric gasket  328  is mounted to the top edges of the front and rear plates  318 ,  320  and surrounds the outlet  326 . 
     From the initial flow conduit  322 , the air/water/debris mixture flows into recovery tank  30  which is an assembly of a bottom member  308  and a top member  310  having a top wall  364 , a pair of sidewalls  366 , and a rear wall  368 . The working air flows from the initial flow conduit  322  to an intermediate working air flow conduit  330  which is defined by a depression  332  formed in the top wall  364  of the recovery tank  30  and a cover plate  336  secured thereto. The depression  332  comprises a bottom wall  338  and a pair of opposed sidewalls  340 . Preferably, the sidewalls  340  initially taper inwardly from the inlet  342  of the intermediate working air conduit a short distance and then ultimately extend parallel to one another approaching the outlet  344  of the intermediate working air conduit  330 . Preferably, the cover plate  336  is formed of a transparent, plastic material, and the top wall  364  and sidewalls  346  of the recovery tank  30  are formed of a smokey, translucent material. Utilizing these materials and the structure of the intermediate flow conduit  330 , the user can easily observe the dirt and water passing up through the intermediate flow conduit  330  and also easily observe the fluid level inside the recovery tank  30 . 
     The outlet a  344  of the intermediate flow conduit  330  is positioned immediately adjacent a an air/water separator baffle  350  which is integrated into the recovery tank  30  and is formed by a downwardly extending rear wall  352 , a pair of parallel, downwardly extending sidewalls  354 , and a bottom wall  356  extending forwardly from the rear wall  352 . A sealing pocket  429  is integrally formed along the rear wall  352 . With this structure, the working air flow enters the hollow interior of the recovery tank  30  and is immediately redirected approximately 180° to travel forwardly and downwardly into the tank interior away from the tank outlet  382 . The water and dirt will enter the air/water separator baffle  350  and strike the various walls of the baffle  350  and fall downwardly into the tank. 
     In addition to the redirection of the working air flow as it enters the tank  30 , the effective cross-sectional area of the working air conduit is dramatically increased as the air/water mixture passes from the intermediate working air conduit into the air/water separator baffle and the recovery tank. This sudden increase in cross-sectional area results in a significant drop in velocity for the working air, thereby assisting in the separation of dirt and water from the air. 
     A fluid containment baffle  370  is mounted inside the hollow interior of the recovery tank  30  and is intended to prevent excessive sloshing of the recovered dirt and liquid and also contain any foam generated inside the tank. The baffle  370  comprises a front, downwardly extending portion  372  and a rear downwardly extending portion  374  which are spaced from one another but interconnected to one another by multiple stringers  376 . The stringers  376  and edges of the front  372  and rear portions  374  define fluid apertures  378  therebetween. Preferably, the baffle  370  is mounted to the rear wall  368 , sidewalls  366 , and top wall  364  of the top member  310  a spaced distance from the bottom member  308 . Preferably, the fluid flow apertures  378  are positioned immediately below the air/water separator  350  so that as the dirt and water drop therefrom, they pass through the apertures  378  into the lowermost portion of the recovery tank  30 . 
     The front  372  and rear  374  portions of the baffle  370  are contoured to prevent excessive sloshing of the recovered liquid during movement of the cleaner  12 . For example, when the user is moving the base assembly  14  forward and then reverses the direction and pulls the base assembly  14  rearwardly, the water and dirt present within the tank will surge toward the front of the recovery tank  30 . The water will strike the sloping top wall  364  of the recovery tank  30  and be deflected rearwardly. Any water which may be deflected upwardly will strike the downwardly extending front portion  372  of the baffle  370  and, therefore, be deflected downwardly to the lowermost portion of the recovery tank  30 . The downwardly extending rear portion  374  of the baffle  370  will similarly deflect fluid downwardly. The baffle  370  serves to prevent excessive sloshing of fluid in the tank and also provides the added benefit of containing any foam which may build up in the tank beneath the baffle  370  spaced away from the air/water separator baffle  350  and fluid outlet. 
     An air flow outlet stand pipe  380  is integrally formed into the bottom member  308  and is provided at the rear of the recovery tank  30 . The stand pipe extends upwardly to a point adjacent the uppermost portion of the recovery tank  30 , opposite the outlet of the air/water separator baffle  350 . In addition, an inlet opening  382  of the stand pipe  380  is positioned vertically above the baffle  370 . With this structure, the substantially dry air exiting the air/water separator  350  will pass around the bottom  356  and sidewalls  354  of the air/water separator  350  and through the inlet opening  382  of the stand pipe  380  whereas the dirt and water will fall through the baffle apertures  378  into the lowermost portion of the recovery tank  30 . 
     A manifold chamber  384  is formed at the bottom of the stand pipe  380  and defined by the bottom member  308  and the foot member  24 . Preferably, an elastomeric gasket  388  is mounted to the top of the manifold chamber  384  to create a substantially air-tight seal between the bottom of the stand pipe  380  and the manifold chamber  384 . The manifold chamber  384  is shown integrally molded to the base member  24 . Preferably however, the manifold chamber  384  is formed separately from the base member  24  and includes downwardly extending hooks (not shown) that engage with cantilevered arms (not shown) on the base member  24 . The hooks are shaped to contact an upper surface of the arms and flex the arms downwardly when the manifold chamber  384  is installed. A locking surface (not shown) on the hooks then engages a lower surface of the arms to lock the manifold chamber  384  to the base member  24 . A flexible conduit hose  386  extends from one end of the manifold to the impeller fan chamber mounted in the lower portion of the upper housing  16 . In view of the fact that the upper housing  16  pivots with respect to the foot member  24  and recovery tank  30 , the conduit  386  is preferably formed of a pliable, yet durable material. 
     A float  390  is provided inside the recovery tank  30  to prevent overfilling of the recovery tank  30  with fluid. The float  390  comprises a buoyant base  392  and a closure plate  394  interconnected to one another by a support plate  396 . The closure plate  394  is dimensioned to fully seal the inlet opening  382  of the stand pipe  380  and prevent the flow of air or liquid therethrough. 
     The float  390  is limited primarily to vertical movement with respect to the recovery tank  30 , with the closure plate positioned above the fluid containment baffle  370  and the buoyant base  392  positioned below the fluid containment baffle  370 . The fluid containment baffle  370  also includes an aperture  398  through which the stand pipe  380  extends. In addition, a narrow slot  400  is also provided in the rear portion  374  of the fluid containment baffle  370  through which the support plate  396  of the float  390  extends. In the assembled position, the closure plate  394  is positioned above the fluid containment baffle  370  and the buoyant base  392  is positioned below the baffle  370 . 
     Movement of the float is constrained because the buoyant base is captured in a float cage defined by the front wall  402  of the stand pipe  380 , a pair of L-shaped walls  404 ,  406  (FIG. 10) extending up from the bottom member  308 , a substantially planar wall  408  extending upwardly from the bottom member  308  intermediate the two L-shaped wall members  404 ,  406  and the rear portion  374  of the fluid containment baffle  370 . Multiple slots  412  or fluid flow apertures are provided between the wall members  404 ,  406 ,  408  and the stand pipe  380  so that fluid will quickly and easily flow into the float cage defined by these elements. As the fluid within the tank and the float cage rises, the float  390  will also rise until eventually, the closure plate  394  nears the inlet opening  382  of the stand pipe  380 . The closure plate  391  is sufficiently drawn against the stand pipe opening  394  by the suction from the vacuum motor  74  to close the air flow therethrough as illustrated by the phantom lines in FIG.  9 . Once this happens, the pitch of the operating vacuum motor  74  is sufficient to warn the user that the recovery tank  30  is full and must be emptied. 
     The cover plate  336  has a triangular-shaped accessory hose access aperture  422  and a lock aperture  428 . A cover closure cap  420  has a spring arm  446  with a barb  448  which seats beneath the wall of the cover plate  336  at the lock aperture  428  when the cover cap  420  is seated over the aperture  428 . A pair of retaining projections  423  extend rearwardly from a front edge of the aperture  422  into recesses  425  in a depending flange  421  of the cover cap  420  when the cover cap  420  is seated over the aperture  428 . The cap  420  can thus pivot about the projections  423  as the cap is fastened over and removed from the aperture  422 . 
     The recovery tank  30  is quickly and easily emptied by first tilting the handle  18  and upper housing  16  rearwardly. Then, the latches  32  are disengaged from the projections  34  on the recovery tank  30 . The user grasps the handle  36  and merely lifts the tank  30  from the foot member  24  and transports it to an appropriate site for emptying the tank  30 . The tank  30  can also be removed from the foot member  24  without tilting the handle  18  and upper housing  16 . In any event the tank  30  can then be emptied by removing a cap  414  mounted to the drainage aperture  416  provided on the rear wall  368  of the tank  30 . Once the tank  30  has been emptied, the cap  414  is replaced, the tank  30  is lowered down onto the foot member  24 , and finally, the latches  32  are snapped over the projections  34  to lock the tank to the base assembly  14 . 
     As seen in FIG. 2, the entirety of the accessory hose  52  is contained on the accessory hose storage rack  50  when the cleaning machine  12  is used for on-the-floor cleaning or when the machine is being stored. When it is desired to use the accessory hose  52 , the user unsnaps the grip tube  64  from the C-shaped clip  66  of the hose rack  50  and unwinds the hose therefrom and then removes the accessory hose mounting member  62  from its corresponding C-shaped clip on the storage rack  50 . Next, the user removes the cap  420  (FIG. 10) from the recovery tank cover plate  336 , exposing the accessory hose flow aperture  422  and inserts the accessory hose mounting member  62  therein. The mounting member  62  comprises an elbow-shaped rigid conduit  424  which receives the flexible hose on one end thereof and a triangular shaped mounting plate  426  on the other end thereof. 
     As seen in FIGS. 11 and 12, the accessory hose flow aperture  422  is preferably formed directly above the air/water separator baffle  350  when the cover plate  336  is mounted to the top member  310  of the recovery tank  30 . The lock aperture  428  is also formed in the cover plate  336 , directly adjacent the accessory hose flow aperture  422 . The accessory hose mounting member  62  comprises a flange  430  which extends downwardly from the triangular support plate  426 . The flange  430  is substantially complementary to the inside edge of the aperture  422  and is adapted to be snugly received therein. A baffle wall  432  extends downwardly along the front edge of the triangular flange  422  and has a recess  432 `a which receive the projections  423 . The baffle  432  extends substantially the entire width of the intermediate working air conduit  330  and extends downwardly a sufficient distance to contact the bottom wall  338  of the conduit to thereby effectively seal the intermediate flow conduit  330  from the air/water separator baffle  350  and the vacuum motor  74 . Therefore, substantially all of the working is air drawn into the recovery tank  30  comes from the accessory hose  52  when the accessory hose  52  is mounted to the base as illustrated in FIG.  12 . 
     The accessory hose mounting member  62  is retained in the aperture  422  by a U-shaped spring arm  434  which is received in the lock aperture  428  and a sealing pocket  429  located immediately below the aperture  428 . The sealing pocket  429  is integrally formed with the rear wall  352  of the baffle  350  and includes a front wall  431  and a pair of side walls  433  extending between the front wall  431  and the baffle rear wall  352 . The spring arm  434  comprises a pair of opposed legs  436 ,  438  connected to each other through a central bight portion  435 ; The leg  436  extends downwardly from the triangular-shaped support plate. A locking barb  440  is provided on the outside edge of the free leg  438  and a projection  442  is provided at the terminal end of the free leg  438 . In use, the bight portion of the U-shaped arm  434  is initially inserted into the lock aperture  428 . As the spring arm  434  is received in the aperture  428  and sealing pocket  429 , the locking barb  440  bears against one edge of the aperture  428 , thereby flexing the free leg  438  inwardly toward the other leg  436 . Eventually, the locking barb  440  will drop below the inside edge of the cover plate  336  at the aperture  428  and the resilient U-shaped spring arm  434  will spring outwardly to seat the barb beneath the cover plate  336  edge. The edge of the cover plate  336  at the aperture  428  will be captured between the outer projection  442  and the locking barb  440  of the spring arm  434 . 
     When the user desires to remove the accessory hose mounting member  62  from the aperture  422 , the user squeezes the free leg  438  toward the inner leg  436  a sufficient distance to bring the locking projection  440  out of contact with the aperture edge. Then, the user lifts the mounting member  62  a sufficient distance to withdraw the spring arm  434 , triangular-shaped flange  430  and baffle  432  from the aperture  422 . Finally, the user repositions the cap  420  in the aperture  422  thereby effectively sealing the aperture  422 . 
     As seen in FIGS. 9 and 10, the structure of the cap  420  is quite similar to the accessory hose mounting member  62  in that it includes an identical spring arm  446  and a substantially complimentary triangular flange extending downwardly therefrom. One key distinction is that the cap  420  does not include the downwardly extending baffle wall which seals the intermediate working air flow path  330 . 
     The preferred embodiment of the cleaning machine  12  includes a rotatively mounted agitation brush which is adapted for easy and instantaneous vertical adjustment. As seen in FIGS. 9 and 13, the agitation brush assembly comprises a brush dowel  450  fixedly mounted on a shaft  452 . The ends of the shaft  452  are received in bearings  454  which in turn are press-fit into inwardly extending bosses  456  provided on a pair of opposed articulating arm members  458 . Alternatively, stub shafts (not shown) can extend from the arm members  458  and the shaft  452  can be replaced with bearings similar to  454  for rotational installation of the dowel  450  on the arm members  458 . Each arm member  458  comprises a back plate  460  with a pivot pin  462  provided at the rear of the plate  460  and a limit arm  464  provided at the front of the plate  460 . In addition, a laterally extending belt guard  466  is preferably integrally formed with the articulating arm  458 . The belt guard  466  extends laterally inwardly enough to cover the drive belt  468  in the assembled position. The belt guard  466  protects the belt  468  from threads and other foreign material becoming lodged therein and also protects the carpet or other surface positioned below the base assembly  14  from the rotating belt  468 . The drive belt  468  extends around a pulley  470  mounted at one end of the brush dowel  450  and a drive shaft and pulley  472  of the brush motor  474 . 
     The pivot pins  462  of the arm member  458  are captured between a bearing surface  476  integrally formed into the bottom of the foot member  24  and a retaining member  478  having a bearing surface  480  formed thereon. The pivot pin  462  is captured between the bearing surfaces  480 ,  476  of the retaining member  478  and the foot member  24 . The retaining member  478  is secured to the foot member  24  by a conventional fastener, such as a screw  482 . 
     The limit arms  464  provided at the front of the retaining members  478  are preferably integrally molded with the retaining members and are adapted to limit the downward movement of the brush assembly relative to the foot member  24 . Each limit arm  464  has a forwardly extending barb  484  provided at the terminal end of the arm  464 . In the operative position, the barb  484  is positioned above a rearwardly extending projection  486  provided on the foot member  24 . As seen in FIG. 9, as the agitation brush assembly extends further and further downward, the barb  484  on the end of the limit arm  464  will contact the projection  486  and prevent any further downward movement. With this floating agitation brush assembly, the cleaning machine  12  according to the invention can almost instantaneously adapt to varying carpet naps or other inconsistencies on the surface being cleaned. The brush arms also allow the rotating brush to drop below the normal floor plane to provide contact with the floor when a bare floor cleaning attachment raises the suction nozzle opening height from the floor. 
     As an alternative to the floating, rotatably mounted agitation brush as seen in FIGS. 9 and 13, a floating strip agitation brush  490  could be incorporated in the cleaning machine  12 , as seen in FIG.  14 . The floating strip agitation brush  490  is easily adapted for incorporation into the cleaning machine  12 . In this embodiment, the strip brush  490  comprises a linear brush body  492  with bristles  494  extending downwardly therefrom and a pair of integrally molded arms  496 . Each of the arms  496  is formed by a pair of opposed plates  498 ,  500  and a pivot pin  502  extending between the rear most edge of the opposed plates  498 ,  500 . The pivot pins  502  in this embodiment are secured to the foot member  24  in the same manner as the pivot pins  462  shown previously in FIG.  13 . Namely, the pivot pins  502  are captured between the bearing surface  476  of the foot member  24  and the bearing surface  480  formed on the retention member  478  which is securely fastened to the foot member  24  by conventional fasteners  482 . With this structure, the strip brush  490  can move vertically in response to changes in the carpet nap or other inconsistencies in the surface being cleaned. 
     As described above with respect to FIG. 1, the accessory hose solution tube mounting  116  is used primarily for connecting an accessory nozzle, such as found in the upholstery tool  68  in order to provide cleaning solution to the surface being cleaned. It is contemplated, however, that an elongate spray wand can be provided as an accessory attachment for the solution tube mounting  116 . The detergent tank  44  could hold an insecticide solution that is mixed with water or other liquid from the clean water tank  42  in an adjustable ratio for the treatment of fleas or ticks, as an example. In use, the vacuum motor  74  and the brush motor  474  would be turned off, with the solution pump  112  turned on to deliver the insecticide solution to a surface. Alternatively, the clean water tank  42  could hold the insecticide solution or some other solution that is to be directly applied to a surface. 
     The water extraction cleaning machine according to the invention overcomes several of the problems of the prior art. Namely, the cleaning machine is easily adapted for a variety of cleaning operations. For example, the detergent to water mixture ratio can be altered nearly instantaneously. In addition, the height of the agitation brush with respect to the suction nozzle opening changes immediately in response to changes in the carpet nap and other inconsistencies in the surface being cleaned. The cleaning machine according the invention also provides easy and convenient means for filling and emptying the clean water and detergent tanks. Similarly, the recovery tank can be quickly and easily removed for emptying or cleaning. Finally, the accessory hose intended for use with the cleaning machine according to the invention is preferably stored on the machine at all times when not in use. This minimizes the storage space required for the machine and accessories and simultaneously ensures that the user has all attachments and accessories contained on the machine, regardless of where the machine is being used. 
     Reasonable variation and modification are possible within the spirit of the foregoing specification and drawings without departing from the scope of the invention.