Motor vehicles – Power – Electric
Reexamination Certificate
2000-05-30
2002-11-19
Johnson, Brian L. (Department: 3618)
Motor vehicles
Power
Electric
C015S319000
Reexamination Certificate
active
06481515
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to autonomous mobile devices and more particularly to self-powered and self-guided surface treating apparatus for treating a surface, such as a floor.
2. Description of the Related Art
Despite a large potential market, autonomous mobile surface treating devices have not been commercially successful to date. Over the years, developers have repeatedly attempted to automate cleaning appliances with highly kinetic cleaning parts such as floor scrubbers and vacuum cleaners. For example, U.S. Pat. No. 5,815,880, issued Oct. 6, 1998 to Nakanishi, discloses a microprocessor controlled cleaning robot wherein rotating scrub pads dispense a cleaning solution. U.S. Pat. No. 5,940,927, issued Aug. 24, 1999 to Haegermarck et al., discloses a microprocessor-controlled autonomous surface cleaning apparatus wherein a rotating brush roller is reversed after it is entangled or blocked. Such autonomous cleaning appliances with highly kinetic cleaning parts are inherently complex and expensive. In addition, a substantial amount of energy is required to move the highly kinetic cleaning parts. Thus, such autonomous cleaning appliances require a large battery capacity to provide even a short duration of use. Moreover, being highly kinetic, these parts may present a safety concern when used around children or pets.
Autonomous mobile cleaning devices with passive cleaning parts are also known. For example, Japanese Unexamined Patent Publication Hei 11-178764 (Japanese Patent Application Hei 9-394774) published Jul. 6, 1999 and Japanese Unexamined Patent Publication Hei 11-178765 (Japanese Patent Application Hei 9-364773) published Jul. 6, 1999, hereinafter referred to as the Ichiro applications, each disclose a “small and simple cleaning robot” having a deformable, dome-shaped cover provided with contact switches that are activated by the deflection of the cover when the robot runs into obstacles. Four separate contact switches, i.e., front, left side, rear and right side, are mounted on the lower portion of the robot frame adjacent the cover. The reliability of the switches depends on the amount of deflection of the cover and the location of the deflection of the cover relative to the switches. For example, if deflection of the cover occurs between two of the switches, the deflection may not be enough to activate the switches. Increasing the number of switches would reduce this problem, but at greater expense and complexity. The robot has independent left and right drive wheels, independently controlled by a microprocessor, that allow the robot to rotate when a collision is sensed by contact switches actuated by deformation of the cover. The robot is also provided with a spring-loaded plate with an upward camber fore and aft which is used to press a “paper mop” onto a floor surface. The paper mop absorbs dust and rubbish from the floor surface. A spring-biased catch clip is mounted to the spring-loaded plate and is used to removably attach the paper mop. Because the deformable cover has a substantial ground clearance, the robot does not sense low-lying obstacles such as floor-mounted heating, ventilation and air conditioning (HVAC) ducts, electric cords, and transitions to carpet. When raised by such a low-lying obstacle, the spring-loaded plate tends to lift the drive wheels, causing the robot to stall. In addition, because the robot departs from a circular shape, i.e., the cover is depicted as oval in a plan view, it is more likely to become trapped when rotation is not possible due to closely spaced obstacles such as adjacent chair and table legs. The wheeled robot further poses an underfoot hazard by virtue of having freely rotating wheels that would cause the robot to act like a roller skate, i.e., “skate-out”, if stepped upon. Though the left and right drive wheels are connected to motors through a belt drive system, little resistance is offered to this skating action. Also, no allowance is made for alternative cleaning parts beyond changing the paper mop.
In a separate line of development, self-propelled toys capable of some degree of autonomous operation have long been known. An early example is reflected in U.S. Pat. No. 367,420, issued Aug. 2, 1887 to Luchs, which describes a clockwork toy carriage that having obstacle sensing bumpers on each end that mechanically reverse the toy's direction of travel upon collision. More recently, U.S. Pat. No. 2,770,074, issued Nov. 13, 1956 to Jones et al., hereinafter referred to as the Jones et al. patent, discloses a compact, self-propelled toy which circumvents obstructions by rotating and moving away from obstacles upon contact by mechanical feelers. Rotation is accomplished by the use of laterally positioned, independent drive wheels, which, when driven in opposite directions, cause the circular toy to rotate around its vertical axis before proceeding thereby allowing the toy to rotate away from obstacles after collision rather than simply reverse its direction. Unfortunately the feelers, which protrude from the circular shell, are prone to catch on obstacles. Moreover, there is no teaching in the Jones et al. patent that the toy might be equipped with active or passive cleaning parts.
Programmable toy robot kits are also well known in the art. These kits such as the Lego Mindstorms Robotic Invention System require assembly and programming. They are directed to the educational value of building robots and require a knowledge of programming. In the same vein, the text,
Mobile Robots,
2
nd
Edition (Joseph L. Jones et al., published by A. K. Peters, Natick, Mass., 1999) teaches how to build a “Rug Warrior” robot having a circular shape in order to be able to rotate while in contact with an obstacle, and provided with contact switches that are depressed by the robot's cover when the cover is deformed during a collision with an obstacle.
Mobile Robots
teaches how a robot may be programmed to circumvent obstacles by programming backing and rotation when the cover collides with an obstacle. The Rug Warrior kit, which has been described in a variety of forms from at least 1994, requires substantial technical expertise to assemble and is not sold equipped with active or passive cleaning parts.
As sold the Rug Warrior kit is equipped with a thin, deformable cover attached to the chassis with three short, flexible tubes. The cover clearance is not adjustable and is typically more than 0.33 (⅓) inch above a hard surface floor. As a consequence, the Rug Warrior does not sense low obstacles and frequently rides up over HVAC ducts, carpet transitions, and electric cords becoming hung up as low parts of the rigid chassis contact the obstacles, making unattended use problematic. As in the Ichiro patents,
Mobile Robots
teaches mounting separate contact switches to lower portions of the rigid chassis adjacent the cover. The reliability of the switches depends on the amount of deformation of the cover and the location of the deformation of the cover relative to the switches. For example, if deflection of the cover occurs between two of the switches, the deflection may not be enough to activate the switches. Further, the flexible tubes do no precisely locate the cover relative to the chassis. This problem is aggravated when the cover or flexible tubes become distorted, e.g., through exposure to excessive heat. Accordingly, the cover may remain pressed against at least one of the contact switches giving a false, continuing indication of a collision. Increasing the number of switches, and increasing the spring constant of each switch to better release the switch contacts, would reduce the reliability problem but at greater expense and complexity. Also as in the Ichiro et al. applications, the wheeled Rug Warrior poses an underfoot hazard by virtue of having freely rotating wheels that would cause the robot to skate out if stepped upon. Though the left and right drive wheels are connected to motors through a drive system, little resistance is offered to this skating action.
Binski Christopher J.
Clendenien Kevin B.
Fisher Charles W.
Genskow Larry R.
Heaton Gary G.
Fischmann Bryan
Johnson Brian L.
Meyer Peter D.
The Procter & Gamble & Company
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