Side brush assembly mechanism

[0001] This application claims the benefit of U.S. Provisional application No. 61/259,580, filed Nov. 9, 2009, and incorporated herein by reference.

[0002] The present invention generally relates to floor surface cleaning equipment. More particularly the present invention relates to a side brush assembly mechanism having an extension/retraction/pivot mechanism for use with such equipment.

[0003] Surface maintenance vehicles and cleaning devices have a long history subject to gradual innovation and improvement toward improved and oftentimes automated performance in removing debris and contamination from floors. These vehicles and devices may be self-powered, towed, or pushed, and/or manually powered and may carry a human operator during cleaning operations. Such vehicles and devices include scrubbers, extractors, sweepers and vacuums, as well as combinations thereof, intended for cleaning, scrubbing, wiping and/or drying a portion of a substantially flat surface both indoors and outdoors. Many such vehicles and devices employ a side brush assembly for accessing a larger floor envelope. Such side brush assemblies make it easier to clean near walls or other obstacles without damaging the machine or the wall while at the same time widening the cleaning path of the machine to increase productivity (area cleaned/time).

[0004] The side brush assembly of such prior art cleaning vehicles often mounts at or near the side of a surface maintenance vehicle and swings outwardly away from a machine center and downwardly toward the surface to be cleaned. Prior art side brush assembly mechanisms have included separate actuators or linkages to lift the side brush assembly and rotate the side brush assembly inwardly or outwardly. Some prior art cleaning vehicles have included side brush mechanisms that provide only a lift motion, such as the side brush mechanism of surface cleaning machine model 530E, manufactured by Tennant Company, of Minneapolis, Minn., while other machines have used two separate mechanisms to control lifting and retracting, such as those provided on machine models 528, 7400, M20, T20, and M30, manufactured by Tennant Company.

[0005] A lift motion of the side brush assembly is desired to raise the brush deck to provide ground clearance when the scrubbing functions are turned off. An extension/retraction motion is desired to extend the deck past the machine envelope when operating, and to retract the deck back when not operating the side brush. Portions of the side brush assembly retracted behind the machine frame are protected from damage.

[0006] Thus, there is a need for an improved side brush assembly mechanism which provides both lift motion and extend/retract motion.

[0007] The present invention teaches, enables and discloses an improved side brush assembly mechanism usable in a floor surface maintenance vehicle. Such a vehicle includes those self-powered and manually-powered cleaning vehicles applied to the task of removing debris and/or cleaning solution from a floor surface. Such a surface may comprise an interior or exterior floor having some limited porosity but preferably comprising finished concrete (whether painted or sealed), asphalt, ceramic tile, resin-based tile, and the like and including most types of flooring typical of commercial and industrial-grade facilities.

[0008] One object of the present invention is to provide a side brush assembly mechanism capable of lifting and retracting the brush deck with a single force generator. In one embodiment of the present invention the force generator is an electric linear actuator developing a tension force on a retractor cable.

[0009] Another object of the invention is the provision of a side brush assembly mechanism having a biasing mechanism for lowering and extending the brush deck. In one embodiment of the present invention springs are used to provide such biasing forces. In one embodiment of the present invention a combination of torsion and air springs are used to lower and extend the brush deck.

[0010] 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.

[0032] Examples of industrial sweeper-scrubbers which may use the present invention are shown in FIGS. 21 and 22. These surface maintenance machines may be used for sweeping and/or scrubbing floors in factories, warehouses, and other industrial or commercial establishments. As shown in FIG. 21, a riding-type surface maintenance vehicle 100 has a frame 120, and is supported on a plurality of front and rear wheels. Typically, such a surface maintenance vehicle 100 includes a variety of implements such as brushes and systems for dispensing cleaning solutions typically composed of detergent and water which suspend dirt. Vehicle 100 includes a vacuum system including a vacuum fan 140, and a vacuum hose 160 in fluid communication with a recovery tank 180. Loaded cleaning solution and other liquid material are usually removed by squeegee assembly 200. Squeegee assembly 200 is mechanically coupled near the rear of a surface maintenance vehicle 100. One example of such a surface maintenance vehicle is disclosed in U.S. Pat. No. 5,455,985, incorporated in its entirety by reference herein.

[0033] Alternatively, FIG. 22 illustrates a walk-behind surface maintenance vehicle, such as a floor scrubbing vehicle disclosed in U.S. Pat. No. 5,483,718, incorporated herein by reference in its entirety. As with the above-mentioned riding-type surface maintenance vehicle, the walk behind surface maintenance vehicle 100 includes a variety of implements such as brushes and is capable of applying cleaning solutions. Vehicle 100 includes a vacuum fan 140, a recovery tank 180, and a vacuum conduit 160 providing fluid communication between squeegee assembly 200 and recovery tank 180. Again, loaded cleaning solution and other liquid material are usually removed by an articulated squeegee assembly 200 located at the rear of the surface maintenance vehicle 100.

[0034] FIG. 1 illustrates a model T16 surface maintenance machine 8 manufactured by Tennant Company with a side brush assembly generally indicated as numeral 10. Side brush assembly 10 includes a brush deck 12 having an electric-powered floor brush 14 for engaging a floor surface during side brush assembly 10 operation. As detailed below, the side brush assembly 10 includes a mechanism for extending the side brush assembly 10 outwardly (away from a machine centerline) and for lowering brush 14 into floor surface contact. Activation of the mechanism is preferably achieved through a switch (not shown) accessible at the control panel, generally indicated by numeral 16.

[0035] FIG. 2 is an isometric rendering of a side brush assembly mechanism 20 in the “up-and-in” mode, e.g., its storage and/or inactive transportation mode. Side brush assembly mechanism 20 includes linear actuator 22 which extends or retracts cable 24 which is routed throughout the lift/retract mechanism. One end of cable 24 is secured to the moving end of actuator 22 and the other end of cable 24 is secured to a linkage assembly as detailed below. Linear actuator 22 is preferably an electric linear actuator which is controlled via a switch. In other embodiments, linear actuator 22 may be hydraulic-based. In yet other embodiments, linear actuator 22 may be replaced with other cable tensioning devices, such as an electric winch, etc.

[0036] A pivot assembly 30 rotates relative to the machine frame to provide the in/out motion of brush deck 12. The pivot assembly 30 is connected to the machine frame via a pivot pin 32. Pivot assembly 30 operates between a range of positions with outward motion restrained by strap 34 and inward motion restrained by contact with instop 36.

[0037] Extending from pivot assembly 30 is linkage assembly 40 which provides the up/down motion of the brush deck 12. The parallel geometry of linkage assembly 40 is important to keep brush deck 12 generally level as the deck 12 adjusts to floor contours. Linkage assembly 40 also operates between a range of positions with upstop pins 42, which are part of pivot assembly 30 as shown in FIGS. 19-20, defining an uppermost extent of travel of linkage assembly 40.

[0038] Cable 24 is routed from linear actuator 22 through pulleys 44, 46 and pivot assembly 30 and is terminated between lower links of linkage assembly 40 as shown in FIG. 18. Pulley 44 is attached to the machine frame, while pulleys 46 are attached to pivot assembly 30.

[0039] Pivot assembly 30 is biased outwardly by outforce spring 47 which is connected between pivot assembly 30 and the machine frame. Outforce spring 47 provides a biasing force tending to extend brush deck 12 away from the machine centerline. Outforce spring 47 is a gas-charged spring assembly. Again, strap 34 limits the extent to which pivot assembly 30 rotates outwardly.

[0040] Brush deck 12 is biased downwardly by downforce spring 50 which connects between the pivot assembly 30 and linkage assembly 40. Mass of the brush deck 12 also contributes a downward force tending to lower the scrub brush into floor contact. Depending on the mass of the brush deck 12, downforce spring 50 may not be necessary.

[0041] In the “up-and-in” mode of FIG. 2, cable 24 and linear actuator 22 resist the down force of spring 50, the out force of spring 47 and gravity force of brush deck 12 and linkage assembly 40, and function to restrain pivot assembly 30 in contact with instop 36 and restrain linkage assembly 40 in contact with upstop pins 42. To lower/extend the brush deck 12, actuator 22 is activated into an extension mode, via for example a switch, and the pivot assembly 30 moves away from instop 36 and the linkage assembly 40 descends away from contact with upstop pins 42 toward ground contact.

[0042] FIG. 3 is an isometric rendering of the side brush assembly mechanism in the “down-and-out” mode, e.g., operational mode. As actuator 22 is extended, pivot assembly 30 pivots about pivot pin 32 to move away from instop 36 and linkage assembly 40 moves to lower brush deck 12 into floor contact. In this orientation of the side brush assembly mechanism 20, the cable 24 (not shown) is slack.

[0043] FIG. 4 is a top-down rendering of the side brush assembly mechanism in the “up-and-in” mode, such as shown in FIG. 2.

[0044] FIG. 5 is a top-down rendering of the side brush assembly mechanism in the “down-and-out” mode, such as shown in FIG. 3. In this orientation, cable 24 (not shown) is slack.

[0045] FIGS. 6-7 are side view renderings of the parallel arm linkage of linkage assembly 40. These figures illustrate that brush deck 12 is maintained generally parallel to the floor. FIG. 6 shows the mechanism in an “up-and-in” mode, such as shown in FIG. 2. In this mode, cable 24 holds the brush deck 12 off the floor surface. FIG. 7 shows the side brush mechanism in the “down-and-out” operational mode. With actuator 22 extended, the cable 24 is slack, allowing the spring 50 (shown more clearly in FIG. 8) to push the brush deck 12 into the floor surface.

[0046] FIG. 8 is a perspective illustration of the side brush assembly mechanism in an “up and in” configuration. Contact is made between linkage assembly 40 and upstop pin 42 and between pivot assembly 30 and instop 36.

[0047] FIG. 9 is a perspective illustration of the side brush assembly mechanism in an “up and in” configuration. As shown, contact is made between a lower link of linkage assembly 40 and pin 42.

[0048] FIG. 10 is a perspective illustration of the side brush assembly mechanism in an “up and in” configuration. Brush deck 12 is movably coupled to linkage assembly 40 via pivot fasteners 90.

[0049] FIG. 11 is a perspective illustration of the side brush assembly mechanism in an “up and in” configuration, with linear actuator 22 fully retracted. Movement of the movable end of linear actuator 22 is constrained via pin 101 traveling within a pair of elongated slots 102. In a preferred embodiment, when the linear actuator is fully extended the cable 24 is slack.

[0050] FIG. 12 is a perspective illustration of the side brush assembly mechanism in an “up and in” configuration. Cable 24 is connected to linkage assembly 40 via connector 110. A pin of connector 110 can be adjusted between a plurality of apertures 112 to control precise positioning of the brush deck 12.

[0051] FIGS. 13-14 are bottom views of the side brush assembly mechanisms providing a comparison between the “up and in” position (FIG. 13) and the “down and out” position (FIG. 14).

[0052] FIGS. 15-16 are top views of the side brush assembly mechanisms providing a comparison between the “up and in” position (FIG. 15) and the “down and out” position (FIG. 16).

[0053] FIG. 17 is a close-up view of pivot assembly 30 and linkage assembly 40. The downforce spring 50 is connected at one end to extension 141 of pivot assembly 30 and at the other end to spring pin 142. Spring pin 142 is connected to an upper link 144 of linkage assembly 40.

[0054] FIG. 18 is a view of the pivot assembly showing connector 110 detached from linkage assembly 40 and spring 50 detached from spring pin 142. Apertures 112 are defined upon an extension 146 extending from plate connector 148. Plate connector 148 is generally L-shaped and rigidly secures together the pair of lower links of linkage assembly 40.

[0055] FIGS. 19 and 20 are perspective illustrations of a main frame of pivot assembly 30. The frame includes a pivot pin receptacle 150 through which pivot pin 32 is received. One or more bearings are provided between pin 32 and the pin receptacle to provide smooth rotation of pivot assembly 30 relative to the machine frame.

[0056] One end of spring 50 is connected to extension 141. Links of the linkage assembly 40 are connected at arm extensions 152, 154. One pulley 46 is connected at pulley sheave 156. Two other pulleys 46 are secured to pivot assembly 30 at apertures 158. A strike plate 162 engages instop 36, for example when cable 24 is retracted.

[0057] Benefits of the side brush assembly mechanism of the present invention include: 1) a reduction in part count compared to existing designs; 2) improved packaging flexibility due to small size; 3) cost savings; and 4) relative simplicity, which leads to increased reliability.

[0058] 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.