WO2003013944A2

WO2003013944A2 - Vehicle with a mechanism for attachment to a surface

Info

Publication number: WO2003013944A2
Application number: PCT/IL2002/000638
Authority: WO
Inventors: Nadav Leshem
Original assignee: Smart Robotics Ltd.
Priority date: 2001-08-06
Filing date: 2002-08-06
Publication date: 2003-02-20
Also published as: AU2002321807A1; WO2003013944A3

Abstract

A vehicle having two motor-powered wheels (104) and surface engaging vacuum cups (120) that generate a surface-attachment force sufficient to hold the vehicle against a surface and to maintain a wheel traction sufficient to permit the wheels to move the vehicle on the surface. The vehicle, that can easily move and maneuver on the surface, may serve as a platform for a cleaning assembly for cleaning vertical glass surfaces of a building.

Description

VEHICLE WITH A MECHANISM FOR ATTACHMENT TO A SURFACE

FIELD OF THE INVENTION

The present invention is generally in the field of vehicles which have the ability to attach themselves to surfaces and thus to the surface^ other than horizontal surfaces, in particular vertical surfaces. In particular, the present invention relates to such a vehicle, which attaches itself to a surface through a vacuum mechanism.

PRIOR ART

The following is a list of some prior art patent documents which are relevant for the purpose of better understanding of the background to the invention:

US 3,209,849, US 3,628,625, US 3,810,515, US 4,132,279, US 4,664,212, US 4,926,957, US 4,971,591, US 4,997,052, US 5,487,440 and WO 93/02760.

BACKGROUND OF THE INVENTION AND PRIOR ART

Vehicles and apparatuses that can climb and move on vertical and other non- horizontal surfaces, are useful for a variely of purposes. Such vehicles can be useful as toys, can be used to perform a variety of task on surfaces not readily accessible, etc.

In the following, the term "vehicle" will be used to designate a vehicle or any other apparatus having a locomotion system permitting it to move on a surface. hi order to move on vertical and other non-horizontal surfaces, a system for attaching the vehicle to the surface increasing the traction needs to be provided. A vehicle that employs a magnet for climbing and moving on a ferrous wall has been disclosed in US 3,810,515. Attachment and traction increasing systems that make use of vacuum, suction or other negative pressure attachment means are referred to in all other patent documents mentioned.

Cleaning the outside of large non-horizontal, particularly vertical glass surfaces is a major maintenance task in today's modem buildings which have large external glass surfaces. The standard way of cleaning such surfaces is to employ individuals that hang from the top of the building by cables or in specific lifts and thus clean these glass surfaces from the outside. It is clear, in addition to this being dangerous, it is a very costly maintenance undertaking.

SUMMARY OF THE INVENTION

It is the object of the invention to provide a novel attachment and locomotion system which permits a vehicle to attach itself and move on a non- horizontal surface. The term "non-horizontal" will be used herein at times to denote a surface that may be inclined, vertical or inverted (namely a surface that faces essentially downward). The vehicle of the invention is particularly suitable for moving on glass surfaces.

It is an object in accordance with a preferred embodiment of the invention to provide such a vehicle, which serves an apparatus for cleaning glass surfaces.

The invention provides, by a first of its aspects, a vehicle that comprises a chassis with two non-synchronous motor-powered wheels that are attached to the chassis and engage a surface on which the vehicle moves. Fitted to the chassis are one or more slidable, surface engaging vacuum cups that generate a surface-attachment force sufficient to hold the vehicle against the surface and to maintain a wheel traction sufficient to permit the wheels to move the vehicle on the surface.

The term "non-synchronous motor-powered wheels" refers to wheels that are powered in a manner that permits unequal powering of the two wheels. Namely, in non-synchronous wheels power may be applied to one wheel, may be applied to the two wheels in an uneven manner or may be applied equally to the two wheels. The non-synchronous motor-powering of the two wheels may be achieved by a single motor connected to the two wheels in a manner permitting both even and uneven power distribution between the two wheels, for example, by the use of a suitable gear system, or may be achieved by powering each wheel with an independent motor.

It should be noted that while the vehicle preferably includes two motor- powered wheels, it is possible, in accordance with some embodiments of the invention, to include additional motor-powered wheels. Furthermore, the vehicle may also include one or more non-motor-powered, namely, freely revolving wheels.

The term "vacuum cup " refers to a device having the general shape of a cup with its open end facing the surface with a vacuum being maintained at its interior. The cup is thereby pulled to the surface with all the cups in vehicle of the invention generating together a force that holds the vehicle to the surface and insures the needed wheel traction. The vehicle of the invention typically includes, two or more vacuum cups. The vacuum cups, that are typically fixed on the chasis on a face thereof that is opposite the surface, have each a surface-engaging portion that is preferably of sufficient flexibility to permit it to engage the surface in a manner so as to seal as best as possible between the cup's interior and the exterior. The vacuum cup's interior is connected to a vacuum source. The vacuum source may, in accordance with an embodiment of the invention, be a vacuum-generating motor held on the chassis or alternatively, in accordance with another embodiment of the invention, may be a remote vacuum source linked to the vehicle through one or more vacuum tubes. The vacuum generated within the vacuum cups need to be sufficient to hold the vehicle tightly against the surface and maintain the needed wheel traction. In the case of a vehicle intended to move on highly sloped, vertical or inverted surfaces, the attachment force should be sufficient to maintain the vehicle on said surface and inhibit the vehicle's downward slide or downward fall, respectively. The downward slide in case of vertical or highly slanted surfaces, is usually inhibited by the friction between the wheels and the surface.

In accordance with one embodiment of the invention, the vehicle serves as a platform for a cleaning assembly for cleaning the surface. This embodiment will be referred to herein at times as the "cleaning embodiment". In accordance with the cleaning embodiment the vehicle moves on the surface, typically highly sloped, vertical or inverted surface, to clean such not readily accessible surfaces. A specific example of the cleaning embodiment of the invention concerns a vehicle that is used as a cleaning device for smooth surfaces of large constructs, such as buildings, e.g. external glass surfaces of buildings.

A vehicle in accordance with the invention may also serve as a platform for a variety of other applications such as a repair platform, a moving advertisement platform, a toy device etc.

The locomotion system of the vehicle of the invention that comprises two non-synchronous motor-powered wheels permits a very high degree of maneuverability of the vehicle on the surface. Typically, each wheel is powered by an independent motor, preferably an electric motor although other motors such pneumatic or hydraulic motor may in principle be used. Such a locomotion system provides for very high maneuverability of the vehicle on the surface. A two-wheel system, even in combination with the vacuum cups, does not provide a sufficiently stable support to the vehicle. Thus the vehicle preferably comprises an auxiliary support, which together with said wheels fixes the orientation of said chassis with respect to the surface. In accordance with one embodiment of the invention, the auxiliary support includes one or more surface-bearing members, which extend from the chassis to the surface. Such a surface-bearing member typically includes an elongated projection that has a surface-bearing end that bears on the surface. The entire projection or at least the surface-bearing end thereof may be made of or coated by a material that forms a low-friction contact with the surface. Such a material may, for example be a plastic such as polytetra-fluro ethylene (sold commercially, for example, under the tradename Teflon™). In accordance with another embodiment, the auxiliary support includes an auxiliary wheel that can rotate about an axis normal to the surface. The rotation of the auxiliary wheel may either a controlled rotation as part of the steering mechanism of the vehicle or may be a free rotation resulting from moments that are imparted on the wheel, for example as a result of the non-synchronous powering of the two non-synchronous wheels. In accordance with yet another embodiment, the vehicle comprises at least motor-powered auxiliary wheel. In accordance with this embodiment, the vehicle thus comprises at least three wheels that are motor-powered. This may provide some improved maneuverability, which may be of significance for some embodiments of the invention.

In the case of the cleaning embodiment of the invention, the auxiliary support may be provided by the wiper blade of the liquid collecting system (see below). In accordance with this embodiment, the auxiliary support may be a combination of the wiper blade and one or more additional support members. By one embodiment the wiper blade and the additional support members are rigidly fixed to the chassis and consequently bear against the surface. In accordance with another embodiment, a mechanism is provided to permit to occasionally lift the blade off the surface. This may be important in case where, for example, the vehicle needs to maneuver, i.e. in the case where the vehicle changes its direction of movement. By one example, at least one of the additional support members is movable between a retracted state and an extended state, in which the extended state extends such that it somewhat lifts the front end of the chassis and accordingly, the blade which is fixed to the chassis is lifted off the surface. In the retracted position of said additional support member, the blade bears against the surface. By another example, the assembly that includes the blade is fitted with a mechanism that directly lifts the blade from the surface or lowers it thereto.

In accordance with the cleaning embodiment of the invention, the vehicle is intended for moving on and cleaning of non-horizontal surfaces, particularly highly slanted, vertical or inverted surfaces. A particular application of the cleaning embodiment is in the cleaning of glass surfaces. However, as will be appreciated, the invention is not limited thereto and the cleaning vehicle of the invention may also be useful for moving on and cleaning other surfaces such as those made of metal, marble, etc. The two main wheels of the vehicle are typically relatively large wheels fixed to the chassis at two opposite sides thereof. The term "relatively large " refers to a wheel having a diameter larger than the distance between the chassis and the surface at the portion of the chassis at which the wheel is fixed. Of the vacuum cups, typically at least one is fixed to a face of the chassis that is opposite the surface, at a portion thereof that lies between the two wheels. The motor that powers the wheel may be connected to the wheel directly or through a gear system.

In accordance with the cleaning embodiment of the invention, the vehicle comprises a cleaning assembly that comprises a cleaning liquid applying system that applies cleaning liquid onto the surface and a liquid collecting system for collecting used cleaning liquid from the surface. The liquid applying system typically includes a cleaning liquid reservoir, liquid emitting nozzles and a liquid release mechanism for controlled release of the liquid out of said nozzles. The release mechanisms may include one or more of a controllable pump, one or more controllable valves, a release control mechanism embodied in the nozzle, etc. The liquid collection system may include a wiper blade that bears against the surface and that wipes the surface as the vehicle moves and a suction arrangement for sucking wiped liquid. While the blade is typically fixed in its position on the surface vis-a-vis the chassis, the blade may also be movable with respect to chassis, e.g. in a manner similar to that of windshield wipers. The suction arrangement may comprise a blower linked to a suction opening proximal to the wiper blade that sucks in the collected liquid. In accordance with one embodiment of the invention the suction opening is an elongated narrow opening alongside and extending throughout essentially the entire length of the blade.

The cleaning embodiment of the invention thus provides an apparatus for cleaning smooth surfaces that comprises a chassis with a driving mechanism fitted thereto for driving the apparatus on the smooth surface including two asynchronous motor-powered wheels. The wheels are typically made of or having at least their external perimeters that engage the surface coated by an elastic coating, such as rubber. Fitted onto the chassis, on a face thereof that is opposite the surface, are vacuum cups with an interior connected to vacuum generating motor and having a surface engaging portions that slidably engage said surface. The vacuum generated within said cups exerts an attachment force that is sufficient to hold the apparatus against the surface with the wheels maintaining traction sufficient to permit them to move the vehicle on the surface. Said apparatus also comprises a cleaning liquid application system and a liquid collection system. The former system comprises a cleaning liquid supply, that may include a cleaning liquid reservoir held on the chassis or a remote reservoir linked to the vehicle through flexible tubes and spraying nozzles for applying the liquid onto the glass surface in a controlled manner, the control being achieved by any one of a number of ways such as those mentioned above. The latter system comprises a wiper device, typically including a blade with a surface engaging edge that is made of or coated by an elastic material such as rubber. The wiper device extends from the chassis that presses against the surface and collects used cleaning liquid as the apparatus moves on the surface and comprises a suction arrangement associated with said wiper device and which sucks collected liquid into a waste liquid receptacle. The waste liquid receptacle may be held on the vehicle or may also be a remote receptacle linked to the vehicle through appropriate tubing. The liquid collection system typically includes also a liquid separating device that separates between sucked air and liquid.

In accordance with an embodiment of the invention, the front-end components of cleaning mechanism may be included on a cleaning unit at the front of the vehicle. The cleaning unit includes: an elastic material-coated blade that lies on the surface and made to collect liquid disposed on the surface as the apparatus moves forward; an elongated narrow opening fitted at the front side of the blade and extending alongside the blade throughout essentially its entire length and linked to a suction arrangement for sucking in liquid collected by the blade; and spraying nozzles for spraying cleaning liquid on the surface in front of said cleaning unit

The collected liquid sucking system, in accordance with one embodiment of the invention comprises a blower device that includes a revolving blower that is housed within housing and creates, within the housing, one or more low pressure zones and one or more high pressure zones, with air entering into the one or more low pressure zones and exiting from the one or more high pressure zones.

The blower device in accordance with this embodiment includes a liquid separation system that defines a liquid collection zone for the liquid that is separated from the incoming air by the liquid separation system. The blower device has a first inlet that opens to one of the low pressure zones and is connected through a first, air conduit to an opening that is proximal to the wiper device and that accordingly sucks in liquid that is collected by the wiper device. The first outlet opens to the liquid collection zone and is connected through a second conduit, to a waste liquid receptacle, such that liquid collected is ducted into this receptacle. The blower device includes also a second inlet that opens to one of the low pressure zones and is connected through a third conduit to the waste liquid receptacle. This second inlet causes the generation of low pressure within the waste liquid receptacle, which is the driving force to drive the collected waste liquid out of said first outlet, through the second conduit into the waste liquid receptacle.

Preferably, the blower device includes also a third inlet that also opens to one of the low pressure zones and connects through a fourth conduit to a liquid cleaning reservoir. Further, in accordance with this preferred embodiment, a fourth conduit is provided that is connected at its one end to the cleaning liquid reservoir and at its other end to the cleaning liquid applying system to collect emitted cleaning liquid that was not applied onto the surface. Through the fourth conduit a low pressure is generated within the cleaning liquid reservoir and this low pressure then serves as the driving force to collect the non-used, emitted cleaning liquid that was not applied onto the surface. The invention also provides a novel liquid applying system that may be used in the vehicle or apparatus of the invention. This novel liquid applying device is also an independent aspect of the invention. The liquid applying device in accordance with the invention, which is particularly suitable for applying minute quantities onto the surface, includes a disk-shaped head that rotates about an axis and that has two side faces and a peripheral face. The orientation of the axis is such that a radial therefrom points to portion of the surface in front of the vehicle. One of the side faces has a circular or annular opening that is coaxial with the axis and leads into a space that is formed within said head and extends internally peripheral to the opening towards the peripheral face. A plurality of openings are formed in the peripheral face, preferably evenly distributed throughout the peripheral face, and that open into said space. A liquid discharge nozzle extends into said space and discharges liquid into said space while the head rotates. The liquid which is discharged from the nozzle against the rotating internal wall of said space is then ejected out of the openings, by the centrifugal force exerted thereon, onto the surface. In view of the axis' orientation, as mentioned above, the cleaning liquid is applied, in small droplets, on a portion of the surface in front of the vehicle.

In accordance with an embodiment of the invention, the nozzle is connected through conduit to a pumping device that pumps liquid to the nozzle. The invention will now be illustrated in the following specific embodiments with reference made to the annexed drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

Fig. 1 is a top perspective view of a vehicle in accordance with one embodiment of the invention.

Fig. 2 is a perspective bottom view of the vehicle of Fig. 1. Fig. 3 is an exploded view of the basic components of the vehicle of Fig. 1. Fig. 4 is a top perspective view of a vehicle in accordance with another embodiment of the invention. Fig. 5 is a top perspective view of a vehicle in accordance with a further embodiment of the invention.

Fig. 6 is a bottom perspective view of the vehicle of Fig. 5.

Fig. 7 is an exploded view of the vehicle of Figs. 5 and 6 showing the vehicle and the cleaning unit separated from one another.

Fig. 8 is a bottom perspective view of a vehicle in accordance with another embodiment of the invention.

Figs. 9, 10, 11 and 12 are, respectively, bottom perspective view, front perspective view, top perspective view and side elevation of the vehicle of Fig. 8 with the top cover removed to permit a better view of the internal components.

Fig. 13 shows, in isolation, the cleaning assembly of the vehicle of Fig. 8.

Fig. 14 shows a longitudinal cross-section through the lines XIII-XIII of Fig. 13.

Fig. 15 is a bottom isometric view of the mechanism for lifting and lowering the blade in a cleaning apparatus in accordance with an embodiment of the invention.

Fig. 16A and 16B are side elevations showing a cleaning apparatus including a blade lifting mechanism of the kind shown in Fig. 15 with the blade in an elevated state and in a lowered, surface-engaging state, respectively. Fig. 17 shows, in isolation, a liquid applying device in accordance with an embodiment of the invention.

Fig. 18 shows the device of Fig. 17 in a partial cross-section.

Fig. 19 shows the device of Fig. 17 with the electric motor removed to illustrate association between the nozzle and the rotating head. Fig. 20A and Fig. 20B show, in combination, a schematic illustration of the manner of control for preparation of a vehicle in accordance with the embodiment of Figs. 7-13.

Fig. 19 is an illustration showing the manner of movement of a vehicle on the surface of the window to clean the window. DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

Reference is first being made to Figs. 1 and 2 showing a vehicle, generally designated 100, that includes a chassis 102, two wheels 104, fitted at a side plate 108 of the chassis and powered each by a respective electric motor device 110 (best seen in Fig. 3) The electric motor device includes an electric motor unit 112 and a gear box 114. The vehicle also includes a control module 115. The vehicle 100 includes a plurality of vacuum cups 120, having each a surface engaging portion 122 and an interior 124 which is connected to a vacuum source, through an opening (not shown in these two figures, but the opening 125 can be seen in Fig. 3).

The vacuum source may include one or more, two in this specific embodiment, vacuum pumps 126, each one connected to one or more vacuum cups through tubings 128. The vacuum generated within cups 120 by the vacuum pumps 126 yields the tight attachment of the vehicle to the surface and to maintain wheel traction to permit wheels 104 to move the vehicle on the surface. In principle, the vehicle may include a single vacuum pump, although providing more than one vacuum pump improves the safety of operation. Preferably, the vacuum attachment system which includes a plurality of vacuum pumps, is designed so that even if one vacuum pump malfunctions, the attachment force imparted by the remaining pump through the vacuum cup to which it is linked, may still be sufficient to maintain the vehicle on the surface. Optionally, the two or more vacuum pumps included in the vehicle of the invention are connected in parallel to all the vacuum cups, with each one of the vacuum pumps serving as a backup for the other. In order to improve the traction, wheels 104 are provided with a friction band 130 that is mounted on the wheels circumference. The friction band 130 is made of an elastic material such as silicon or rubber.

Fixed to the chassis are two surface bearing members 134, each having the form of an elongated projection, extending from the face of the chassis opposite the surface with a free end that bear on the surface. In combination, wheels 104 and surface bearing members 134 provide a rigid support to the chassis and together fix the orientation of the chassis with respect to the surface.

Fig. 3 shows the manner of assembly of the vehicle. The chassis is made of two side plates 108 and connecting bars 107. The two motor devices 110 being each fitted, e.g. by screws, at the one of the side plates 108. An axle 116 protrudes out of gear box 114 and fits within opening 117 to connect with an axle receiving opening 118 of wheel 104. The vacuum pumps 126 are fixed each on one of the connecting bars 107. Two vacuum cups 120, each with an opening 125 that when assembled, is connected to the vacuum pump and one surface bearing member 134 are fitted to the opposite faces of the connecting bars 107.

The vehicle comprises also an associated electric power supply (not shown) which may be a battery held on the vehicle or alternatively, may be a remote power source connected to both motors 110 and vacuum pumps 126. As can be seen in Figs. 1 and 2, the wheels are relatively large with their diameter being larger than the distance between the chassis and the surface at a portion of the chassis at which the wheels are fixed.

Reference is now being made to Fig. 4. In the embodiment shown in Fig. 4, rather than having a vacuum pump on the vehicle, the vehicle is connected through tubings 129, to a remote vacuum source, illustrated schematically as module 129A. Similarly, the power source as well as the control module may also be remote from the vehicle.

A vehicle in accordance with the invention, such as that of the embodiments shown in Figs. 1-4, may serve as a platform for a variety of applications. According to one preferred embodiment, referred to above as the "cleaning embodiment" and which will be illustrated further below with reference to Figs. 5-14, the vehicle serves as the platform for a cleaning assembly which serves for cleaning of surfaces on which the vehicle moves. There may however be a variety of other applications of the vehicle, for example as a robotic repair platform of non-accessible surfaces, as a platform for use in displaying moving advertising messages, as a robotic toy and a variety of other applications.

In the following, the invention will be further illustrated with reference to the cleaning embodiment of the invention. It is, however, understood that the invention is not limited thereto.

A vehicle in accordance with the cleaning embodiment is in fact an apparatus for cleaning surfaces. A particular example is an apparatus for cleaning external glass surfaces of buildings. Such a cleaning apparatus is typically a robotic system that can move and perform its intended task, i.e., cleaning, on the surface according to predefined missions. Such an apparatus, in addition to including a vehicle platform in accordance with the invention, also includes a cleaning assembly. Such a vehicle may be remotely guided, e.g. by cable or by radio control, or alternatively, may be a stand-alone, robotic, apparatus with an ability to navigate and clean the glass surface. In order to have this robotic ability, the vehicle is provided with the necessary sensors to sense its position and the necessary servo mechanisms. These are all known per se and the artisan should be able to incorporate the proper navigational and control mechanisms to the vehicle platfonn of the invention. The following description will not deal with the control mechanism, it being understood that such control mechanism and its installation and design is within easy reach of the man of the art.

An apparatus 200 for use in cleaning of surfaces, particularly external glass surfaces of buildings, can be seen in Figs. 5 and 6 and in an exploded view in Fig. 7. In these figures, components which have a similar function to those seen in Figs. 1-3, have been given like reference numerals shifted by 100. Thus, for example, component 104 (the wheels) has a similar function to component 204 in Figs. 5-7.

Apparatus 200, as can be seen particularly in Fig. 7, includes the vehicle platform 240 and the front end cleaning assembly 242. Vehicle platform 240 is similar in many respects to vehicle 100 of Figs. 1 and 2 but with a number of differences. For one, the chassis is somewhat wider, and the front connecting plate 207 holds four suction cups 220. In addition, a notable difference between the two vehicles is in that the vehicle 100 of Figs. 1 and 2 includes a surface-bearing member 134 which is missing in the case of the vehicle of Figs. 6-9. The additional point of support to that provided by wheels 204, in this embodiment, is provided by the wiper member 248 that has the wiper blade 250 which bears on the surface. The front end cleaning unit 242 is fixed to the vehicle platform 240 by screw-engagement with side plate 208.

As can be seen in Fig. 6, wiper member 248 is provided with an elongated narrow opening 244, being proximal and alongside the entire length of the blade. This opening is the front end of a suction mechanism including suction tube 252 which leads to a blower shown schematically as block 254 in Fig. 5. The details of an example of such a mechanism will be described below.

The cleaning unit also includes a cleaning liquid application mechanism, details of an exemplary mechanism will also be described below. A cleaning apparatus in accordance with the embodiment of Figs. 5-7, as well as a cleaning apparatus of the kind shown in Figs. 8-14, the cleaning assembly including the blade that bears on the surface and which wipes the liquid therefrom, is included in the front of the apparatus. The blade is typically formed so as to be adapted to wipe the liquid while the liquid moves forward. This forward motion cleaning is particularly advantageous to permit cleaning at edge portions of the cleaned surface.

Another embodiment of cleaning apparatus 300 in accordance with the cleaning embodiment of the invention can be seen in Figs. 8-14.

The apparatus 300 includes a chassis 302, holding two wheels 304 and holding on a bottom face a plurality, six in this specific embodiment, of vacuum cups 306. At the front of the vehicle is a liquid collection device 308 having at its bottom a blade 310 made of a flexible material such as rubber. Blade 310 is supported by a reinforcement rubber member 312 (seen best in Fig. 14). As can also be seen, apparatus 300 has a top cover 314 (that has been removed in Figs. 9-12 to allow viewing of various components covered thereby. Above the liquid collection device is a liquid application device 320, the function of which and the manner of its operation to be explained further below.

The apparatus 300 of Figs. 8-14 is typically connected to a remote power source (not shown) but nevertheless is provided with auxiliary batteries 324 which permit, in the case of a power failure, to maintain some power to the vacuum pumps so that the apparatus will not detach from the surface.

The apparatus 300 also includes a cleaning liquid reservoir 326 and a waste liquid receptacle 328.

The apparatus 300 includes also a plurality of mechanical sensors (three of which 330 and 331 can be seen in Fig. 8 the operation of which will be explained below).

Similarly as in the previously shown embodiments, the apparatus 300 according to this embodiment includes one or more vacuum pumps 332, only the bottom part of which can be seen in Figs. 8 and 9. A single pump, having a plurality of vacuum outlets may be used. Alternatively, in order to ensure redundancy in this important function, important to improve safety of operation, two or more vacuum pumps may be provided.

Seen in Figs. 8 and 9 is also a linear-servo motor 332 that can extend or retract an elongated rod 334 fitted at its bottom end with an end member 335 made of a material that can slide over the surface. Extension of rod 334 brings the end member 335 to rest on the surface whereby it serves as a point of support of the chassis (together with the wheels). In its fully extended position, it causes the lifting of the liquid collection device 308 off the surface and permitting the apparatus to move with device 308 lifted. In order to further understand the manner of operation of the device, reference will be made in particular to Figs. 11, 13 and 14.

The apparatus includes a blower device 340, which can be seen in Fig. 11 and also in cross-section in Fig. 14, and that includes a motor 342 (the bottom of which can also be seen in Figs. 8 and 9) that is linked to a revolving rotary fan device that includes a fan 343 and a rotor 344. In its rotation, the rotor 344 sucks in air which generally moves in the direction of arrows 346 in Fig. 14. The blower device has a housing 349 with a first inlet 350, leading into a low pressure zone of the apparatus 300 that connects through an air conduit 352 to the internal space 354 of the liquid collection device that ends in a narrow opening 356 extending alongside the entire length of blade 310. When rotor 344 revolves, air is sucked in through inlet 350 and sucks in also liquid collected through the wiping action of wiper blade 310. While air can penetrate through the opening in the side of rotor 344, liquid cannot penetrate therethrough and accordingly collects at a liquid collection zone 360. A second conduit 362 opens to that zone and links between it and waste liquid receptacle 328. A third conduit 364 connected between receptacle 328 and a second inlet 366 within a low pressure zone of blower device 340. Through this connection, low pressure is maintained within waste liquid receptacle 328 to permit removal of waste liquid from the liquid collection zone within blower device 340. A fourth conduit 368 connects between cleaning liquid reservoir 326 and the same negative pressure zone within device 340. This creates low pressure within reservoir 326. A fourth conduit 370 linked reservoir 326 and liquid application device 320. Through the low pressure maintained in reservoir 326, conduit 370 sucks axis cleaning liquid that was not applied by device 320 onto the surface (the manner of operation of which will be explained further below).

Apparatus 300 also includes a liquid pump 374 that pumps, via conduits 376 and 378, cleaning liquid to the nozzle assembly 380.

Reference is now being made to Figs. 15, 16A and 16B illustrating a mechanism in accordance with an embodiment of the invention, for lowering the wiper blade to the surface and lifting it therefrom. Fig. 15 shows the chassis and the blade lifting-lowering mechanism stripped for most of the apparatuses component, for ease of illustration. Figs. 16A and 16B are side elevations showing the apparatus in one operational state where the blade is lifted from the surface (Fig. 16A) and another operational state in which the blade bears against the surface (Fig. 16B). In Figs. 15-16B, the like reference numerals to those used in Figs. 8-14 has been used, shifted by 200, to designate functionally similar components. For example, components 504, 506 and 520, are functionally equivalent to the respective components 304, 306 and 320.

The chassis, generally designated 600 includes two side plates 602, each of which has an opening 604, designed to accommodate a motor (not shown) that powers wheels 504. The two side plates 602 are linked to one another by means of a connecting strut 606. Fitted into connecting strut 606 is a linear motor 608 the bottom of which can be seen in Fig. 15. Blade 510 with its associated reinforcing member 512 are linked to lever system that include two side arms 610 and a central arm 614. The three arms are connected to one another via connecting rods 620. The two side arms 610 are pivotally fixed to side plate 602 by means of a connecting member 622.

Motor 608 includes an extension rod 626, which may be extended or retracted by the action of motor 608, and which is pivotally connected at 628 to arm 614. By the extension or retraction of rod 626, the entire assembly which includes blade 510 can be lowered onto the surface or lifted therefrom. As can also be seen, the upper face 630 of arms 610 is shaped in a manner so as to match the shape of the lower face 632 of plate 602 to permit maximal upward displacement thereof. The blade-including assembly in its fully upward state can be seen in Fig. 16A. As can be seen, linked to the chassis is an additional support member 630 which in the state shown in Fig. 16A bears against the surface 632. This support member is typically made of low friction material such as Teflon™. In the state shown in Fig. 16B, blade 510 bears against surface 632 and in this state the additional support member 630 is lifted off the surface. Reference is now being made to Figs. 17-19 showing a cleaning liquid application device 320 according to an embodiment of the invention. The device includes a disk-shaped head 400 with side faces 402A and 402B and a peripheral face 404. An electric motor 410 held in a holder 412 is connected to rotating head 400 so as to cause it to revolve about its axis 414. Face 402A of the disk-shaped head 400 has an annular opening 416 opening into a space 420 defined within head 400 which extends peripherally from opening 416. A plurality of openings 422 connect between space 420 and the periphery.

Nozzle assembly 380 has a narrow extension 424 that extends into opening 416 and terminates at an opening that faces radially towards the internal lateral face 426 of space 420. Consequently, cleaning liquid emitted, typically trickled out of the nozzle, by the action of pump 374, and hits the internal lateral face 426. As the disk rotates in the direction of arrow 430 the impinging liquid is subjected to centrifugal forces and consequently is ejected out of openings 422. The disk-shaped head 400 is housed within the housing 434 with a portion of the disk-shaped head that is proximal to the surface being outside the housing. The interior of the housing 434 has an opening 438 that is connected to conduit 370, a proximal portion of which is shown in Figs. 17-19. As may be recalled, a low pressure is generated within reservoir 326 and consequently air is continuously sucked in through conduit 370. As a result, all liquid expelled out of head 400 within the housing is then sucked back into reservoir 326 as represented by arrow 440.

The disk-shaped head is oriented so that a portion of the peripheral face 400 faces a portion of the surface in front of and proximal to blade 310. Thus, as the vehicle advances forward liquid is applied onto the surface in front of blade 300 and shortly after the liquid is applied before it has time to dry, blade 310 collects the liquid which is then sucked in through opening 356 to be eventually collected within receptacle 328 as explained above.

The liquid ejected out of head 400 is sprayed onto the surface along an essentially straight line in front of and essentially parallel to the blade. The distance between the blade and the sprayed line depends on the orientation of the axis 414 of head 400.The extent of the portion of the head 400 that protrudes out of the housing 434 in fact controls the length of the sprayed line. In certain embodiments of the invention the length of the sprayed line may be controlled by moving the housing 434 relative to the head 400 to change the extent of the portion that remain outside the housing in order to control the length of the sprayed line.

Reference is now being made to Figs. 20A and 20B. Fig. 20A is simplified as a representation of the control unit of a cleaning embodiment according to the invention. It includes a CPU (central processing unit) 700, a FPGA (field programmable gate array) 702 and accelometer 704 to continuously determine the vehicle's spatial orientation. The CPU receives an input from an analog sensor AL1, while the FPGA module receives input from digital sensors Dl, D2 and D3. The FPGA module controls the motor driver's M1-M7: Ml driving motor 410 of the liquid application device, M2 driving the motor 342 of the blower device 340, M3 and M4 driving the vacuum pumps, M5 and M6 driving the two wheels (the wheel motors are similar to those shown in the embodiments of Figs. 1-4 and 5-7) and M7 driving the liquid pump 374.

Digital sensors DI1 and DI2 are linked to mechanical devices that permit the vehicle to sense that one of its sides approaches an edge of its sides, while the digital sensor DI3 permits the apparatus to locate an edge ahead of it. When approaching one of the sides of the surface, the apparatus can automatically change its direction. When advancing towards an edge, sensed by sensor DI3 the apparatus will first stop motor drivers Ml drivers 1 and M7, to cease the liquid application operation and will eventually change its course by first backing and then turning to a different direction. While backing, projection 334 (see Figs. 8 and 9) may be made to extend towards the surface to lift the wiper blade above the surface.

Fig. 21 shows, by way of example only, a manner of movement of the apparatus on a cleaned surface. The apparatus is first placed on an arbitrary point (A) on the surface, typically close to the edge (El). It then advances forward until reaching edge (El) and then the apparatus straightens to move parallel to (El) along arrow (B). When reaching the upper edge (E2), the apparatus then backs in the directed represented by arrow (C) and then turns to move normal to the previous direction along the line represented by arrow (D). When reaching the edge (E3) the vehicle advances backwards along arrow (E) and then turns and proceeds along the direction of arrow (F) parallel to edge (E3) until reaching edge (E4). Thereafter the apparatus moves in succession in a similar manner, along the lines represented by arrows (G-L) and thereby eventually the entire surface is cleaned. It should be noted that the movement is designed such that the vehicle can initially, by moving along arrows (B), (D) and F) to measure the dimensions of the surface and thereafter, the logic within the control unit of the apparatus can design the movement of the apparatus over the surface for optimal cleaning.

Claims

CLAIMS:

1. A vehicle comprising:

- a chassis;

- two asynchronous motor-powered wheels attached to the chassis and engaging a surface; and

- one or more slidable, surface engaging vacuum cups that generate a surface- attachment force sufficient to hold the vehicle against the surface and to maintain a wheel traction sufficient to permit them to move the vehicle on the surface.

2. A vehicle according to Claim 1, wherein each of the wheels is powered by a separate electric motor.

3. A vehicle according to Claims 1 or 2, comprising one or more surface-bearing members that bear against said surface and which together with said wheels fixes the orientation of said chassis with respect to the surface.

4. A vehicle according to Claim 3, wherein the one or more surface-bearing members are elongated projections extending from the chassis with their free end bearing against the surface.

5. A vehicle according to Claim 3, wherein the one or more surface-bearing members comprise a wheel that bears against the surface and that can change its orientation about an axis substantially normal to the surface according to moments acting thereon.

6. A vehicle according to any one of the preceding claims, wherein the vacuum engagement device comprises a vacuum cup with a surface-engaging portion, the vacuum cup's interior being connected to a vacuum source.

7. A vehicle according to Claim 6, wherein the vacuum cup is fitted onto the chassis on a face thereof that is opposite said surface.

8. A vehicle according to Claim 6, wherein the vacuum source is a vacuum- generating motor held on said chassis.

9. A vehicle according to Claim 6, wherein the vacuum source is a remote vacuum source linked to the vehicle through one or more vacuum tubes.

10. A vehicle according to any one of the preceding claims, wherein said surface is a highly sloped or an inverted surface and the surface-attachment force is sufficient to maintain the vehicle on said surface and inhibit the vehicle's downward slide or downward fall, respectively.

11. A vehicle according to Claim 10, wherein the downward slide is inhibited by the wheel's traction.

12. A vehicle according to any one of the preceding claims, wherein the wheels are fitted at two opposite sides of the chassis.

13. A vehicle according to Claim 12, wherein the diameter of the wheels is larger than the distance between the chassis and the surface at a portion of the chassis at which the wheel is fixed.

14. A vehicle according to Claim 13, comprising one or more vacuum cups fitted onto a face of the chassis that is opposite said surface of which at least one is fitted at a portion of the chassis that is between the two wheels, the cups having a surface-engaging portion the vacuum cup's interior being connected to a vacuum source.

15. A vehicle according to Claim 14, wherein the vacuum source is a vacuum generating motor fitted on said chassis.

16. A vehicle according to Claim 14, wherein the vacuum source is a remote vacuum source linked to the vehicle through one or more vacuum tubes.

17. A vehicle for moving on and cleaning a sloped or an inverted surface, comprising: a chassis; two asynchronous motor-powered wheels attached to the chassis and engaging the surface; one or more slidable, vacuum engagement devices that generates a surface- attachment force sufficient to hold the vehicle against the surface and for the wheels to maintain a traction sufficient to permit them to move the vehicle on the surface; and a cleaning assembly that comprises a cleaning liquid applying system that applies cleaning liquid onto the surface and a liquid collecting system for collecting used cleaning liquid from the surface.

18. A vehicle according to Claim 17, wherein the cleaning liquid applying ₅ system comprises a cleaning liquid reservoir, liquid emitting nozzles and a liquid release mechanism for controlled release of the liquid out of said nozzles.

19. A vehicle according to Claims 17 or 18, wherein the liquid collecting system comprises a wiper blade that bears against the surface and a suction arrangement for sucking wiped liquid. ιo

20. A vehicle according to Claim 19, comprising an additional support member associated with a mechanism for reciprocating said support member between an extended position and a retracted position; in the extended position an end of said member bears on the surface and extending to an extent so as to lift the blade from the surface.

15 21. A vehicle according to Claim 19, wherein the wiper blade is associated with a mechanism for displacing it away from the surface and repositioning it thereon.

22. A vehicle according to any one of Claims 17-21, wherein the vacuum engagement device comprises a vacuum cup with a surface engaging portion, the vacuum cup's interior being connected to a vacuum source.

20 23. A vehicle according to Claim 22, wherein the vacuum source is a vacuum- generating motor held on said chassis.

24. A vehicle according to Claim 22, wherein the vacuum source is a remote vacuum source linked to the vehicle through one or more vacuum tubes.

25. A vehicle according to any one of Claims 14-16, wherein said surface is a 25 glass surface.

26. A vehicle according to any one of Claims 17-24, wherein the cleaning-liquid applying system comprises: a disk-shaped head rotating about an axis and having two side faces and a peripheral face, the axis being oriented such that a tangent thereto points to a

30 portion of the surface in front of the vehicle; one of the side faces having a circular or annular opening coaxial with the axis and leading to a space formed within said head and extending internally peripheral to the opening towards the peripheral face; a plurality of openings being formed in the peripheral face opening to said space; - a liquid discharge nozzle extending into said space to discharge liquid into said space while said head rotates.

27. A vehicle according to any one of Claims 17-26, comprising: a blower device including a revolving blower housed within a housing creating, within the housing, one or more low pressure zones and one or more high pressure zones, air entering into the one or more low pressure zones and exiting from the one or more high pressure zones; a liquid separating system within the blower device defining a liquid collection zone; first inlet that opens to one of the low pressure zones and connects through a first, air conduit to an opening proximal to said wiper blade to suck in liquid collected by the wiper blade; a first outlet that opens to the liquid collection zone and connects through a second conduit, to a waste liquid receptacle; and a second inlet that opens to one of the low pressure zones and connects through a third conduit to the waste liquid receptacle.

28. A vehicle according to Claim 27, comprising: a third inlet that opens to one of the low pressure zones and connects through a fourth conduit to a cleaning liquid reservoir; and a fourth conduit connected at its one end to the cleaning liquid reservoir and at its other end to the cleaning liquid applying system to collect emitted cleaning liquid that was not applied onto the surface.

29. An apparatus for cleaning a smooth surfaces, comprising: a chassis; a driving mechanism fitted on said chassis for driving the apparatus on the glass surface and comprising two asynchronous motor-powered wheels; vacuum engagement means for generation of a surface-attachment force sufficient to hold the apparatus against the surface with the wheels maintaining a traction sufficient to permit them to move the vehicle on the surface; a cleaning liquid supply and means for applying the cleaning liquid onto the glass surface; and a liquid collection system for collecting used cleaning liquid from the surface.

30. An apparatus according to Claim 29, being an independent apparatus and comprising a control module for controlling operation of the apparatus and a power source carried on the vehicle.

31. An apparatus for cleaning smooth surfaces, comprising: a chassis; a driving mechanism fitted on said chassis for driving the apparatus on the smooth surface and comprising two asynchronous motor-powered wheels; - vacuum cups with an interior connected to vacuum generating motor and having a surface engaging portions that slidably engage said surface, and being fitted on said chassis on a face thereof that is opposite said surface; the vacuum generated within said cups exerting an attachment force sufficient to hold the apparatus against the surface with the wheels maintaining a traction sufficient to permit them to move the vehicle on the surface; a cleaning liquid application system comprising a cleaning liquid supply, spraying device for applying the liquid onto the glass surface in a controlled manner; and a liquid collection system that comprises a wiper device extending from the chassis that presses against the surface and collects used cleaning liquid as the apparatus moves on the surface and comprises a suction arrangement associated with said wiper device and which sucks collected liquid into a waste liquid receptacle.

32. An apparatus according to Claim 31, being an independent apparatus and comprising a control module for controlling operation of the apparatus and a power source carried on the vehicle.

33. An apparatus according to Claims 31 or 32, wherein cleaning liquid ₅ application system comprises a cleaning liquid reservoir, spraying device for applying the liquid onto the smooth surface and liquid conduits between the reservoir and the spraying device.

34. An apparatus according to Claim 33, wherein the spraying device comprises:

₁₀ - a disk-shaped head rotating about an axis and having two side faces and a peripheral face, the axis being oriented such that a tangent thereto points to a portion of the surface in front of the vehicle; one of the side faces having a circular or annular opening coaxial with the axis and leading to a space formed within said head and extending internally peripheral to the opening towards the peripheral face; 15 a plurality of openings being formed in the peripheral face opening to said space; a liquid discharge nozzle extending into said space to discharge liquid into said space while said head rotates.

35. An apparatus according to Claim 34, comprising a pumping device for pumping cleaning liquid to the liquid discharge nozzle.

20 36. An apparatus according to any one of Claims 31-35, wherein the wheels surface-engaging faces are made of, or covered by an elastic material.

37. An apparatus according to any one of Claims 31-36, wherein the wiper device has a blade with a surface-engaging blade that is made of or is coated by an elastic material.

25 38. An apparatus according to any one of Claims 31-37, wherein said suction arrangement comprises an elongated narrow opening alongside and extending throughout essentially the entire length of said blade linked through a conduit to an air blower for blowing in liquid-sucking air through said opening.

39. An apparatus according to any one of Claims 31-38, wherein said liquid collection system includes a waste liquid collection receptacle that collects the liquid sucked through the suction arrangement.

40. An apparatus according to Claim 39, wherein the liquid collection system includes a liquid separator separating between the collected liquid and the sucked air.

41. An apparatus according to any one of Claims 31-40, wherein the chassis has a front end fitted with a cleaning unit and two sides each one fitted with one of the wheels, the radial faces of the wheel being made of or coated by an elastic material that maintains a high friction contact with the glass surface; the cleaning unit includes: an elastic material-coated blade that lies on the surface and made to collect liquid disposed on the surface as the apparatus moves forward; an elongated narrow opening fitted at the front side of the blade and extending alongisde the blade throughout essentially its entire length and linked to a suction arrangement for sucking in liquid collected by the blade; and spraying nozzles for spraying cleaning liquid on the surface in front of said cleaning unit.

42. An apparatus according to any one of Claims 36-41, wherein the attachment force maintains the wheels and said blade in tight contact with the surface.

43. An apparatus according to any one of Claims 37-41, comprising a mechanism for lifting the blade including one or more pins that are brought in touch with the surface as the blade is lifted.

44. An apparatus according to any one of Claims 31-43, comprising: a blower device including a revolving blower housed within a housing creating, within the housing, one or more low pressure zones and one or more high pressure zones, air entering into the one or more low pressure zones and exiting from the one or more high pressure zones; a liquid separation system within the blower device defining a liquid collection zone; first inlet that opens to one of the low pressure zones and connects through a first, air conduit to an opening proximal to said wiper device to suck in liquid collected by the wiper blade; a first outlet that opens to the liquid collection zone and connects through a second conduit, to a waste liquid receptacle; and a second inlet that opens to one of the low pressure zones and connects through a third conduit to the waste liquid receptacle.

45. An apparatus according to Claim 44, comprising: a third inlet that opens to one of the low pressure zones and connects through a fourth conduit to a cleaning liquid reservoir; and a fourth conduit connected at its one end to the cleaning liquid reservoir and at its other end to the cleaning liquid applying system to collect emitted liquid that as not applied onto the surface.

46. An apparatus according to any one of Claims 31-45, wherein the spraying device comprising: a disk-shaped head rotating about an axis and having two side faces and a peripheral face, the axis being oriented such that a tangent thereto points to a portion of the surface in front of the apparatus; one of the side faces having a circular or annular opening coaxial with the axis and leading to a space formed within said head and extending internally peripheral to the opening towards the peripheral face; a plurality of openings being formed in the peripheral face opening to said space; a liquid discharge nozzle extending into said space to discharge liquid into said space while said head rotates.

47. An apparatus according to Claim 46, wherein said nozzle is linked to a pump that pumps cleaning liquid to the nozzle.

48. A device for spraying liquid on a surface, comprising: a disk-shaped head rotating about an axis and having two side faces and a peripheral face, one of the side faces having a circular or annular opening coaxial with the axis and leading to a space formed within said head and extending intemally peripheral to the opening towards the peripheral face; a plurality of openings being formed in the peripheral face opening to said space; a liquid discharge nozzle extending into said space to discharge liquid into said space while said head rotates.

49. A device according to Claim 48, wherein said nozzle ejects the liquid in an axial direction.

50. A device according to Claims 48 or 49, wherein the rotating head is included within a housing, a portion of the head proximal said surface being outside said housing.

51. A device according to any one of Claims 48-50, comprising a liquid-collecting arrangement that collects liquid ejected from the rotating head within the housing and towards the surface.

52. A device according to Claim 51, wherein the liquid collecting arrangement comprising an opening into the interior of the housing that is connected to a fluid collecting system at its other end.