Suspension for a surface maintenance appliance

Abstract

An improved suspension system for coupling a surface maintenance tool or appliance to a surface maintenance machine is disclosed. In preferred embodiment, the suspension system includes a 4 bar linkage which permits the surface maintenance tool to be raised and lowered relative to the surface maintenance machine into selective contact with the floor surface, a spring assembly transferring spring force to the surface maintenance tool, and a selectively controllable actuator connected to the spring assembly for controlling a level of the spring force so that a controlled level of surface maintenance tool work is performed upon the floor surface.

Description

RELATED APPLICATION

[0001] This application claims the benefit of priority of U.S. Provisional Patent Application No. 60/292,675, filed on May 21, 2001, the disclosure of said application being incorporated by reference herein.

FIELD OF THE INVENTION

[0002] The present invention relates generally to surface maintenance or conditioning machines, and particularly those machines employing one or more surface maintenance or conditioning appliances or tools that perform one or more tasks including, among others, scrubbing, sweeping, and polishing or burnishing. The more specifically, the present invention is particularly directed to a suspension system for a surface maintenance appliance, and specifically a burnishing assembly.

BACKGROUND OF THE INVENTION

[0003] Surface maintenance machines that perform a single surface maintenance or surface conditioning task are, of course, well known. Surface maintenance machines are generally directed to applications such as floor surfaces, or simply floors. The term floor, as used herein, refers to any support surface, such as, among others, floors, pavements, road surfaces, ship decks, and the like.

[0004] Commonly floor or surface maintenance machines are constructed having a single surface conditioning appliance or system so as to only sweep, others to scrub, while still others only to polish or burnish. It is of course possible to construct a single surface maintenance machine to perform one or more of the aforementioned surface maintenance tasks.

[0005] One example of a multi-task floor conditioning machine is disclosed in the U.S. Pat. No. 3,204,280, entitled, “Floor Cleaning & Waxing Machine,” issued to Campbell, the enter disclosure of which is incorporated by reference herein in its entirety for any and all purposes. Another is disclosed in U.S. Pat. No. 4,492,002, entitled, “Floor Cleaning Machine,” by inventors Waldhauser, et al, the entire disclosure of which is incorporated by reference herein in its entirety for any and all purposes. Disclosed therein is a forward sweeper assembly followed by a scrubber assembly that is followed by a squeegee assembly.

[0006] Yet, another example of a multi-task floor conditioning machine is disclosed in a PCT application having publication WO 00/74549, published Dec. 14, 2000, entitled, “Floor Cleaning Machine,” by inventors Thomas, et al, the entire disclosure of which is incorporated by reference herein in its entirety for any and all purposes. The machine disclosed therein performs the task of sweeping, scrubbing, and burnishing, and includes a squeegee assembly in combination with a vacuum system for removing cleaning solution from a floor subsequent to a cleaning and scrubbing operation.

[0007] As illustrated in WO 00/74549, thereshown is a single unitary walk-behind machine that is transportable across a floor. Successively attached to the machine, from front to back, are independent floor maintenance systems. At the forward section of the machine is a sweeping system. At the rearward section of the machine—machine steering control—is a burnishing system. In between the sweeping system and the burnishing system is a scrubbing system including forward scrubbing brushes coupled to a cleaning solution dispensing system and rearward following squeegees coupled to a liquid vacuum system for recovering expended cleaning solution.

[0008] Burnishing systems generally include a scheme for controlling the degree of burnishing applied to a floor surface depending upon the type of floor surface intended to be burnished. Burnishing systems well known in the art commonly include a driver assembly which includes a working appliance or tool such as a pad or brush affixed to a driver that is rotatably driven by a driver motor. The driver assembly of the burnishing systems of the prior art have been selectively raised and lowered by an actuator so as to achieve an intended force or pressure against a floor surface intended to be polished or burnished.

[0009] Scrubbing systems are analogous to burnishing systems, and are also well known in the art. Scrubbing systems commonly include a driver assembly including rotatable scrubber in the form of a brush, pad, or the like, and a scheme for controlling the degree of scrubbing applied to a floor surface depending upon the type of floor surface intended to be scrubbed. Too much scrubbing of course may deleteriously affect the floor surface requiring further maintenance. The scrubber driver assemblies for scrubbing systems, like burnishing systems, are of course well known in the art and commonly include one or more rotatable brushes driven by a driver motor affixed to a scrubber head. Scrubber heads of the prior art have been selectively raised and lowered by an actuator coupled to the driver so as to achieve an intended force or pressure of the brush against a floor surface intended to be scrubbed. Examples of the latter are taught in U.S. Pat. Nos. 4,757,566; 4,769,271; 5,481,776; 5,615,437; 5,943,724; and 6,163,915, the entire disclosures of which are incorporated by reference herein in its entirety for any and all purposes.

[0010] Common to some control systems of the aforementioned prior art patents is the employment of a current sensor that monitors the current drawn by the driver motor. In some of the aforementioned systems of the prior art a “pressure sensor” is employed that is representative of the pressure of the scrubber head against the floor. Still others attempt to control torque load on the motor indicated by the sensed motor current.

[0011] Sweeper systems are also analogous to burnishing systems. Sweeper systems commonly include a rotatable sweeper system brush driven by a driver motor. Like burnishing and scrubbing systems the sweeper system brush may be lowered and raised relative to a floor, which may more or less affect the floor surface.

[0012] Commonly, floor conditioning machines are powered by a rechargeable battery supply. Of course, the battery voltage applied to the various floor conditioning systems or appliances, and particularly to the driver motor, will decay in relation to the energy discharged by the battery and the total time of discharge. With respect to burnishing systems, the mechanical burnishing power delivered to the floor is therefore dependent upon the voltage and current delivered to the driver motor.

[0013] Burnishing appliances or systems on such floor maintenance machines have several factors that place design demands on the suspension system from the floor maintenance machine that are suspended. This is so since commonly the burnishing pad is somewhat surrounded in part by peripheral portion of the driver and is surrounded by an attached skirt extending from peripheral portions of the driver—the skirt preventing dust and debris from being injected into the environment. In operation, upon powering of the burnishing assembly driver motor, a vacuum is established within the chamber formed by the burnishing system driver and skirt. This in turn causes a vacuum which tends to pull the burnishing assembly toward the floor. This vacuum may be controlled by way of providing breather vents or ports in the skirt.

[0014] It should be understood that as the burnishing assembly suspended from the frame of a floor maintenance machine is pulled toward the floor by the aforesaid vacuum greater load upon the driver motor results as well increased working power or force against the floor results, the magnitude of which is dependent upon the type of floor surface intended to be burnished or polished. Driver motor load current controllers known in the prior art burnishing systems or scrubber systems, may of course be employed to more or less yield substantially controlled working power or force against the floor surface, as well as prevent drive motor burn out.

SUMMARY OF THE INVENTION

[0015] An object of the present invention is to provide a suspension system for a floor maintenance appliance suspended from a frame associated with a floor maintenance machine.

[0016] An object of the present invention is to provide a suspension system for burnishing appliance or assembly suspended from a frame associated with a floor maintenance machine.

[0017] A variable load suspension system has been disclosed for varying the work force of a surface maintenance appliance upon a surface intended to be affected. In one exemplary embodiment, a series combination of an actuator and a spring assembly is coupled to a frame at one end, and the other end thereof is coupled to the surface maintenance appliance by way of an appropriate linkage. In the preferred embodiment of the invention, the spring assembly, and specifically the spring, generally extends in the direction of transport of the surface maintenance machine 10, and the actuator causes motion transverse to the surface intended to be affected.

[0018] The actuator and driver motor of the surface maintenance appliance are intended to be controlled by any of the aforementioned control systems known in the art as well as others without departing from the true spirit and scope of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 is a side view of a walk behind surface maintenance machine employing a suspension system in accordance with the present invention for suspending a burnishing system.

[0020] FIG. 2 is a partial perspective view of the suspension system assembly in accordance with the present invention.

[0021] FIG. 3 is a side view showing further details of the suspension system assembly illustrated in FIG. 2.

[0022] FIG. 4 is top plan view illustrating suspension system components in accordance with the present invention.

[0023] FIG. 5 is a schematic block diagram of an exemplary embodiment of a control system for a floor maintenance appliance for controlling the work output delivered to a floor surface.

DETAILED DESCRIPTION OF THE INVENTION

[0024] Illustrated in FIG. 1 is walk behind surface conditioning machine 10 in accordance with the present invention. A burnishing assembly generally indicated by numeral 100 is suspended from a frame 20 by way of a suspension system assembly in accordance with the present invention generally indicated by numeral 200, and particularly illustrated in FIG. 2 as will be described in further detail herein. FIG. 1 graphically depicts the available range of motion of the burnishing head or assembly 100 when coupled to the frame in accordance with the present invention. Namely, a transport position 101, lowered operating position 102, and pad changing position 103.

[0025] Illustrated in FIG. 2 is a perspective view of the suspension system 200 in accordance with the present invention. In FIG. 2, burnishing assembly 100 has been omitted. Suspension system 200 includes an actuator 220 pivotally coupled to frame 20 through coupling member 224, and having an actuator rod 222 pivotally coupled to a spring assembly 400 (not shown in FIG. 2, shown in FIG. 4). Spring assembly 400 is coupled to a 4-point or four parallel bar linkage system 215 through coupling brackets 250L and 250R.

[0026] A pair of mounting bracket 210L and 210R is intended to be rigidly attached to the burnishing assembly driver member 110 upon which a driver motor is generally mounted.

[0027] Burnishing assembly 100 is coupled to frame 20 by way of the 4-point or 4-bar linkage 215 including bars 230L, 230R, 240L, and 240R. Ends 232L, 232R, 242L, and 242R are pivotally coupled to frame 20 (not shown) by way rotatable mounted pins, bolts, or the like mounted through apertures 234L, 234R, 244L, and 244R, respectively. The four point linkage system is of course well known for generally lifting and lowering an assembly with generally transverse movement relative to the ground plane upon which the assembly may rest. In other words, permits vertical movement while fixed in a lateral position relative to a reference frame, namely the frame 20 of the surface maintenance machine 10.

[0028] Suspension coupling bracket 250L has a first end 252L rigidly secured to bar 240L by way mounting bolts 253, welding, or the like. The other end of bracket 250L is pivotally coupled to one end of spring assembly 400 as will subsequently be described in detail below. Similarly, bracket 250R has a first end 252R rigidly secured to bar 240R by way mounting bolts 253 (not shown) or the like. The other end of bracket 250R is also pivotally coupled to one end 410 of spring assembly 400, and is substantially identical to suspension coupling bracket 250L but is substantially hidden from view in the figures.

[0029] Spring assembly 400 is further described in FIG. 4. As illustrated in FIG. 4, spring assembly is essentially a preloaded draw spring well known in the art having a helical spring housing 420 enclosing, in part, helical spring 410 with rod 430 passing therethrough. One end 423 of housing 420 is pivotally coupled to actuator rod 222. The opposite end of rod 430 is affixed to pin assembly member 440 by way of a threaded bolt 443, or the like. One end of spring 410 is coupled to an anti-rotation plate 445 having extending tabs 447 protruding through slots 446 of housing 420. The other end of spring 410 engages housing end member 441 of housing 420 through which rod 430 passes therethrough.

[0030] Pin assembly member 440 includes a pair of pins or rod shape members 43 IL and 43 IR intended to be pivotally coupled to suspension coupling bracket end members 253L and 253R of suspension coupling brackets 250L and 250R, respectively. As illustrated in the figures, rod shaped members 431 pass through, in part, arcuate slots 255L (255R not shown). These slots may be omitted as their function provides for obtaining the appliance assembly position identified as numeral 103 in FIG. 1 while maintaining pivotal coupling. It should also be noted that suspension coupling brackets 250L and 250R are somewhat “s-shaped” so as to permit unobstructed movement of the 4-point suspension system, while at the same time permit 4-point suspension system to be affected, in part, by the combination spring assembly 400 and actuator 220.

[0031] Actuator 220 includes a mounting member 224 for pivotally coupling actuator 220 to frame 20. Similarly end member 223 of actuator rod 222 is pivotally coupled to housing end member 423 by way of any suitable pivotal coupling, for example a travis pin assembly or the like as indicated by numeral 425.

[0032] In an exemplary embodiment of the invention, draw spring assembly may have a free length spring of 29 inches, an installed length of 15 inches (compressed spring) with a 20 lbs.-inch rate of spring force. It is of course should be understood by those skilled in the art that the size of draw spring assembly 400 may be embodied by way of a wide array of physical sizes depending upon the weight of the burnishing assembly, and the available room and cost considerations associated with the surface maintenance machine 10.

[0033] In operation of the suspension system of the present invention, in the actuator retracted position, the burnishing assembly is the machine transport position indicated by numeral 101 in FIG. 1 and the assembly is away from the floor surface.

[0034] In the “operate position,” the actuator is extended a predetermined amount until the burnishing head makes contact with the floor surface while under the influence of the draw spring assembly 400. In turn the actuator 220 and burnishing head driver 110 motor may be controlled to achieve regulated work force upon the surface intended to be affected. Actuator 220 is selectively controlled during operation to adjust the degree of spring compression, and hence the degree of spring force transferred by spring assembly 400 to burnishing assembly 100. Actuator 220 may be a hydraulic actuator (not shown) or other known actuation device appreciated by those skilled in the relevant arts.

[0035] The present invention provides a horizontal packaging technique for achieving variable spring load in the vertical direction of a surface maintenance assembly or appliance, for example burnishing, scrubbing, waxing assemblies, and the like.

[0036] A variable load suspension system has been disclosed for varying the work force of a surface maintenance appliance upon a surface. A series combination of an actuator and a spring assembly is coupled to a frame at one end, and the other end thereof is coupled to the surface maintenance appliance by way of an appropriate linkage. In the preferred embodiment of the invention, the spring assembly 400 generally extends in the direction of transport of the surface maintenance machine 10 (generally parallel with the surface), and the actuator causes motion transverse to the surface intended to be affected.

[0037] It should be recognized that alternatively, the positions of actuator 220 and draw spring assembly 400 could be interchanged as should be recognized by those skilled in the art.

[0038] In accordance with another aspects of the present invention, brackets 210L and 210R are provided with arcuate slots 577 whereby pins coupling bar members 230L and 230R may be lifted upward from points 213L and 213R. With the arcuate slots 577 and corresponding slots 255L and 255R in coupling brackets 250L and 250R respectively, the entire mechanism may be lifted. Locking members 280L and 280R are provided with a slot so that bar members 250L and 250R may be pivotally coupled to members 280L and 289, respectively, permitting the assembly 100 to be raised to pad changing position as indicated by numeral 103 in FIG. 1.

[0039] Referring to FIG. 5, a schematic block diagram is illustrated representing one exemplary embodiment of a control system for a floor maintenance appliance that controls the work output delivered to a floor by a rotatable work tool, such as a polishing pad, a scrubber, a brush, etc. Such a control system may be utilized in conjunction with embodiments of the present invention to control linear actuator 220. Additional aspects of this control system are disclosed in U.S. patent application Ser. No. ______, filed on May 21, 2002, entitled “Control System for a Floor Maintenance Appliance,” having a common assignee with the present application, and being incorporated in its entirety by reference herein. In FIG. 5, a floor maintenance assembly 10 is configured as a burnishing system suspended from a frame 22 associated with a floor maintenance machine (not shown) by way of an actuator 20. The actuator 20 is configured to raise and lower the maintenance assembly 10 relative to the floor 24. Although a burnishing tool is illustrated in the Figures, it should be understood that the maintenance assembly 10 may be configured to perform other types of maintenance tasks, such as sweeping and scrubbing, or a combination of maintenance tasks. As shown in FIG. 5, the maintenance assembly 10 includes a rotatable driver 12 having a rotatable shaft 14 coupled to a driver motor 16. The rotatable work tool for performing the work task is a burnishing pad 18 that is coupled to a rotatable driver 12. The maintenance assembly 10 and the actuator 20 may be implemented by way of a wide array of components and techniques, many of which have been described in the aforementioned published patents and publications, among others.

[0040] 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.

Claims

1. A surface maintenance machine for operation upon a floor surface, said surface maintenance machine comprising:

a surface maintenance tool coupled to the machine through a plurality of linkages which permit the surface maintenance tool to be raised and lowered relative to the surface maintenance machine into selective contact with the floor surface;

a spring assembly including at least one adjustable spring, said spring assembly being coupled to the surface maintenance tool so that a spring force is transferred to the surface maintenance tool; and

a selectively controllable actuator coupled to the spring assembly, said actuator controlling a level of the spring force so that a controlled level of surface maintenance tool work is performed upon the floor surface.

2. The surface maintenance machine of claim 1, wherein the plurality of linkages comprises a four bar linkage device.

3. The surface maintenance machine of claim 1, wherein the spring assembly is coupled to at least one of the plurality of linkages.

4. The surface maintenance machine of claim 1, wherein the spring assembly includes a spring retained within a spring housing.

5. The surface maintenance machine of claim 1, wherein the actuator is connected to the spring housing.

6. The surface maintenance machine of claim 1, wherein the actuator is an electric actuator.

7. The surface maintenance machine of claim 6, wherein the actuator is an electric linear actuator.

8. The surface maintenance machine of claim 1, wherein the actuator is a hydraulic actuator.

9. The surface maintenance machine of claim 1, wherein the spring assembly is coupled to the surface maintenance machine in a generally parallel orientation relative to the ground surface.

10. The surface maintenance machine of claim 9, wherein the spring assembly is generally elongated and is coupled to the surface maintenance machine so that an elongated dimension of the spring assembly is aligned generally in a direction of machine motion.

11. The surface maintenance machine of claim 1, wherein the spring force transferred to the surface maintenance tool tends to lift the surface maintenance tool away from the floor surface.

12. A suspension device for coupling a surface maintenance appliance to a surface maintenance machine, said suspension device comprising:

a plurality of linkages coupled between the surface maintenance device and the surface maintenance machine, said plurality of linkages permitting the surface maintenance device to be selectively transitioned relative to the surface maintenance machine between a plurality of positions;

a spring assembly having at least one spring, said spring assembly transferring a spring force to at least one of the plurality of linkages and the surface maintenance device; and

a controllable spring actuator in engagement with the spring assembly for selectively controlling the spring force being transferred to the surface maintenance device during operation.

13. The suspension device of claim 12, wherein the plurality of linkages comprises a four bar linkage device.

14. The suspension device of claim 12, wherein the spring assembly is coupled to at least one of the plurality of linkages.

15. The suspension device of claim 12, wherein the spring assembly includes a spring retained within a spring housing.

16. The suspension device machine of claim 12, wherein the actuator is connected to the spring housing.

17. The suspension device of claim 12, wherein the spring assembly is coupled to the surface maintenance machine in a generally parallel orientation relative to the ground surface.

18. The suspension device of claim 17, wherein the spring assembly is generally elongated and is coupled to the surface maintenance machine so that an elongated dimension of the spring assembly is aligned generally in a direction of machine motion.

19. The suspension device of claim 12, wherein the spring force transferred to the surface maintenance tool tends to lift the surface maintenance tool away from the floor surface.

20. The suspension device of claim 12, wherein one of the plurality of positions of the surface maintenance device relative to the surface maintenance machine is a substantially perpendicular orientation relative to a normal operational position.

21. A vehicle for burnishing a floor surface, said vehicle being transportable across the floor surface during a burnishing operation, said vehicle comprising:

a burnishing head including a motor driven burnishing pad;

a plurality of linkages coupled between the burnishing head and the vehicle, said plurality of linkages permitting the burnishing head to be selectively transitioned relative to the vehicle between a plurality of positions;

a spring assembly having at least one spring, said spring assembly transferring a spring force to the burnishing head; and

a controllable spring actuator in engagement with the spring assembly for selectively controlling a burnishing force being transferred to the surface during operation.

22. The suspension device of claim 21, wherein the plurality of linkages comprises a four bar linkage device.

23. The suspension device of claim 21, wherein the spring assembly is coupled to at least one of the plurality of linkages.

24. The vehicle of claim 21, wherein the spring assembly is coupled to the vehicle in a generally parallel orientation relative to the ground surface.

25. The vehicle of claim 24, wherein the spring assembly is generally elongated and is coupled to the vehicle so that an elongated dimension of the spring assembly is aligned generally in a direction of vehicle motion.

26. The vehicle of claim 21, wherein the spring force tends to lift the surface burnishing head away from the floor surface.

27. The vehicle of claim 21, wherein one of the plurality of positions of the burnishing head relative to the vehicle is a substantially perpendicular orientation relative to a normal operational position.