Abstract:
A squeegee blade assembly and method of use for a floor surface maintenance machine. A blade/guide subassembly is inserted into a channel of a scrub head prior to operation. During operation, the subassembly is retained with the channel via friction and/or protruding structures. During a blade exchange procedure, the subassembly is retracted from the channel prior to separation of the blade from the guide. Interaction with a protruding structure within the channel signals to an operator that the subassembly has been properly positioned.

Description:
RELATED APPLICATIONS 
     This application claims priority under 35 U.S.C. 119(e) from provisional U.S. Patent Application No. 60/866,413, filed Nov. 17, 2006, the contents of which are incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to surface cleaning devices and more particularly to a floor surface cleaning device utilizing a liquid cleaning solution and a vacuum system for recovering soiled solution from a floor surface. 
     BACKGROUND OF THE INVENTION 
     Floor maintenance scrubbers are well known. These devices typically include a source of cleaning solution, solution applying means for distributing cleaning solution onto the floor surface, scrubbing means for engaging a wetted floor surface and a vacuum system for removing soiled cleaning solution from the floor surface. The vacuum system typically includes one or more squeegee elements, such as disclosed in U.S. Pat. Nos. 6,895,633; 6,705,332 and 6,602,018, each being incorporated by referenced herein. The squeegee blades in these types of machines are often a wear/service item. As the blades wear, the ability of the machine to pick up soiled cleaning solution and/or water is diminished. In some particularly harsh environments, squeegee blades are replaced multiple times during the life of the machine. Many times this is done by the operator in the field where the availability of tools is limited. Some prior art machines provide thumb screws for retaining the squeegee blades. 
     Tennant Company&#39;s model 433 Walk Behind Scrubber has included removable squeegee blades and retainers, similar to the design of  FIG. 6 . In this design, the retainers and blades are connected together via fasteners. The design purportedly provided for tool-less blade exchange by increasing the clearance around the blades, so the blades could be pushed or pulled within a retainer-receiving channel. Two significant limitations have been associated with this approach. First, since the soft rubber blade was not supported along its length it tended to bend during insertion into the channel. Additionally, when the blade was pulled, a portion of the blade tended to grab channel walls. Furthermore, the friction between rubber and aluminum was often too great to allow free sliding without increasing the clearances between the rubber and aluminum parts. 
     Another problem of the prior art has been bonding of the rubber blade to the aluminum or plastic retainer. Compression of the rubber blade within the retainer often resulted in adherence of the blade material to the retainer. Blade sticking made removal difficult without unscrewing the retainer. 
     The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. The novel features which are believed to be characteristic of the invention, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present invention. 
     SUMMARY OF THE INVENTION 
     The present invention relates to a squeegee assembly and method of engaging a blade subassembly within a scrub head or other structure. In one embodiment, a subassembly of squeegee blade and channel guide are together movably retained within a channel of the scrubber head, with the subassembly being selectively released from the channel during a blade exchange procedure. 
     A method of engaging squeegee blades with a scrubber head is also disclosed. In one embodiment, the squeegee blades and channel guide subassembly are inserted into a channel of the scrub head until contact with a distal protrusion at an opposite end of the channel. Contact with a proximal protrusion may be released just prior to the contact with the distal protrusion, signaling to an operator that the blade/guide subassembly has been properly inserted into the channel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an elevational view of scrubber machine embodying the principles of the present invention. 
         FIG. 2  is a side elevational view of a scrub head subassembly of the scrubber machine of  FIG. 1 . 
         FIG. 3  is a perspective illustration of a disassembled squeegee blade assembly of  FIG. 2 . 
         FIG. 4  is a detailed side view of the scrub head of  FIG. 2 . 
         FIG. 5  is a detailed perspective view of a retainer utilized in the assembly of  FIG. 2 . 
         FIG. 6  is an exploded perspective view illustration showing components of a prior art scrub head. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  illustrates a scrubber machine  10  incorporating aspects of the present invention. Scrubber  10  includes handle  11 , operator control  12 , and clean and soiled cleaning solution tanks (not shown). Scrubber  10  also includes a vacuum fan (not shown) in fluid communication with scrub head  20  having a powered scrub brush  21  rotating between a pair of squeegee blade assemblies  22 . 
       FIG. 2  is a detailed side elevational view of squeegee blade assembly  22 .  FIG. 3  illustrates squeegee blade assembly  22  in a disassembled perspective view. Assembly  22  includes chassis  23 , cover  24 , squeegee blades  25 , guides  26  and blade retainers  27 . Wheels  28  support blade assembly  22  upon a ground surface during use. Assembly  22  is held together with fasteners including threaded fasteners  29 , and nuts  30 . Chassis  23  includes a vacuum tube outlet  31  adapted to be connected to a vacuum tube (not shown) in communication with the vacuum fan. End  32  of chassis  23 , which is opposite outlet  31 , is open to allow air and soiled cleaning solution to pass through outlet  31  and into the vacuum tube. Blades  25  may be differently configured and/or sized, as shown in  FIG. 2 . For example, a front blade  25  may include corrugations and be longer (in a vertical direction) than the rear blade. The front blade  25  may also be more compliant than the rear blade. 
     To permit some movement between chassis  23  and cover  24 , chassis  23  is positioned internal to cover  24  under an internal spring load supplied by springs  34 . During use, springs  34  provide a spring bias tending to displace chassis  23  away from cover  24 . This movable connection between cover  24  and chassis  23  permits blades  25  to follow undulations or other irregularities upon the floor surface. 
     While the figures illustrate blade assembly  22  positioned relative to a forward-mounted scrub brush  21 , the blade assembly  22  may also find application to rear-mounted structure. As a result, aspects of the present invention may be embodied on a rear-mounted squeegee assembly for a floor cleaning machine. 
     Referring now to  FIG. 4 , a detailed side view of the squeegee blade assembly of  FIG. 2  is shown. In the illustrated embodiment, guide  26  has been inserted into channel  40  formed by a portion of retainer  27  and chassis  23 . An amount of clearance between guide  26  and retainer  27  permits guide  26  to move within channel  40  in a lateral direction (side-to-side motion relative to machine direction of travel) as well as other directions. To retain guide  26  within channel  40  during guide  26 /blade  25  movement, protrusion  41  is sized to engage guide  26  and limit further lateral travel of guide  26 . A similar protrusion (not shown) is positioned at the other end of channel  40 . Channel  40  is generally G-shaped and a portion of channel  40  engages a groove of blade  25 . 
       FIG. 5  is a detailed view of an end of retainer  27  showing protrusion  41 . Protrusions  41  are sized to permit guide  26  to be introduced into channel  40  during blade insertion while also restraining guide  26  within channel  40  during intended operation of scrubber  10 . During a blade exchange procedure, protrusion  41  locally compresses guide  26  and blade  25 . The height of protrusion  41  may be optimized to concentrate the load during insertion/retraction on the most compliant portion of the subassembly, relatively soft squeegee blade  25 . 
     When blades  25  are to be replaced on scrubber  10 , an operator may tip scrubber  10  upwardly to expose the bottom of scrub head  20 . The operator can then grab and slide the blade  25 /guide  26  subassembly out of channel  40 . This extraction procedure is facilitated by the low friction interface between guide  26  and retainer  27 . The interface between the blade/channel subassembly and retainer  27  is optimized with slight clearance to allow for lateral movement under expected tolerance conditions. Guide  26  provides rigidity to the subassembly, so it can be pushed into and pulled out of channel  40  with consistency. In one embodiment, blades  25  and guides  26  could be provided as disposable wear items. 
     Once the blade/channel assembly is in the proper position, protrusions  41  are exposed in the assembly as shown in  FIGS. 4 and 5 . During a blade exchange procedure, as the blade/guide subassembly is inserted into channel  40 , an operator would initially sense contact between protrusion  41  and guide  26 , followed by a release and a reduced drag signaling that the subassembly has been fully inserted to its proper position. 
     Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. Moreover, the scope of the present application is not intended to be limited to the particular embodiments of the process, machine, manufacture, composition of matter, means, methods and steps described in the specification. As one of ordinary skill in the art will readily appreciate from the disclosure of the present invention, processes, machines, manufacture, compositions of matter, means, methods, or steps, presently existing or later to be developed that perform substantially the same function or achieve substantially the same result as the corresponding embodiments described herein may be utilized according to the present invention. Accordingly, the appended claims are intended to include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.