Abstract:
The invention disclosed relates to the remote cleaning of outer surfaces of windows or facades of high rise buildings without the need for workers located outside the building wall. In fact, the cleaning operation effectively duplicates the conventional manual cleaning operation, such that a minimum of cleaning liquid is used, and no means is required for removal of excess cleaning liquid. The apparatus comprises a rectangular master frame and a parallelogram sub-frame contained therein, suspended from the top of the building to a position opposite a window to be cleaned. A novel cleaning tool, including mechanical scrubbing means e.g. a brush and mechanical scraping means e.g. squeegee and a washing liquid spray means, is carried on an insertion tool attached to the parallelogram sub-frame, and brought to bear against the window outer surface to be cleaned, as required. The brush and squeegee are rotatable and moveable in any desired planar motion in the plane of the window surface, which is not possible with any known remotely operated window cleaning apparatus. The entire cleaning operation is effected and monitored by an operator in a safe remote location, for example, by means of closed circuit television.

Description:
FIELD OF THE INVENTION 
     This invention relates to a remotely operated high rise building window and facade cleaning apparatus, and in particular to a remotely operated window glaze cleaning apparatus. 
     BACKGROUND OF THE INVENTION 
     The conventional method for cleaning the outer glazed surfaces of sealed windows of high rise buildings is by means of a manual operation by workers in a swing stage (sometimes referred to as a cradle or balcony) which the workers can raise or lower along the side of the building to a position opposite the window glaze to be cleaned. The conventional cleaning method involves two steps. First, the glazed surface is brushed or scrubbed with a cleaning brush soaked in cleaning fluid. This step is followed by a squeegeeing or scraping operation in which the workers, using a plastic or rubber blade (squeegee) scrape all excess liquid from the glaze surface leaving it in a streak free pristine condition. In the case of buildings of intermediate height the same cleaning operation is sometimes performed by workers lowered over the side of the building in bosun chairs. Both methods of cleaning outer glazed surfaces are expensive and constitute one of the most dangerous occupations in industry. 
     There is a well known need for a window glaze cleaning device for cleaning glazed surfaces that are not readily accessible, such as the glazed outer surfaces of sealed windows of high rise buildings which is efficient and does not require workers on the outside of the building. 
     DESCRIPTION OF THE PRIOR ART 
     Numerous inventions have been proposed for accomplishing the cleaning of high rise building facades and/or window glaze outer surfaces by remote means. In general, mechanical devices proposed up to the present time involve the raising and lowering of a cleaning head along the building wall. As it passes along the surface to be cleaned the cleaning head sprays cleaning fluid on the surface and scrubs it with brushes. Most of these inventions involve the use of rotating, or non-rotating, brushes which are forced to travel vertically along the building facade and scrub the facade and/or outer glazed window surfaces with a liquid cleaning solution. Means are then provided for removing the remaining cleaning fluid from the glaze surface. Good discussions are to be found on prior art up to the year 1977 in U.S. Pat. No. 4,025,984, and, up to the year 1980, in U.S. Pat. No. 4,198,724. 
     One disadvantage of at least some known automatic window washers is that they can satisfactorily clean a window only while moving in one direction ie. either only while moving upwardly or only while moving downwardly. This results in time being wasted waiting for the apparatus to be repeatedly retracted to its starting position A second disadvantage is that they require a relatively large amount of washing liquid to clean a given window area. Because these devices generally spray the washing liquid directly on the window surface and because the scrubber brushes and removal means are generally not positioned in proximity to the location at which the washing liquid is sprayed on the window surface, a large amount of washing liquid is needed to adequately and uniformly wet the surface to be cleaned and to keep the dirt particles in suspension in the washing liquid for a sufficient length of time to enable the removal means to collect it. 
     Furthermore, due to the limited amount of weight supported by a suspension line support system, either (1) the window washer must be refilled quite often, or (2) the dirty waste water must be recycled, or (3) a complicated filtration system must be used to clean the waste water. 
     The next problem, that of removing excess fluid, is addressed by dragging a scraper, or squeegee, along the surface behind the brushes (U.S. Pat. No. 4,198,724). In other devices (U.S. Pat. No. 4,025,984) atmospheric air is caused to rush over the surface to cause evaporation of the excess fluid. This general approach is typical of most devices proposed up to this time for effecting the cleaning operation. None of these devices has been generally adopted by the high rise building cleaning industry so far. 
     Typical of these proposed devices is the one described in U.S. Pat. No. 4,198,724. It is of interest to compare it and its functioning with that of the present invention. This earlier device comprises a cleaning head which is to be lowered from the building roof by cable while guided horizontally by a pair of adjacent vertical mullions of the building wall. Cleaning fluid is dripped onto horizontal roller brushes which are oscillated axially while dragged along the surface to be cleaned. Plastic horizontal squeegee blades follow the rollers and their function is to scrape off excess cleaning fluid which is eventually removed by a vacuum suction system. At the end of the up or down travel the head has to be repositioned between the next pair of adjacent mullions before the cleaning process can be continued. Also, the cleaning head is designed for one window width, only, as it must be dragged or lowered vertically between pairs of adjacent mullions. 
     The present invention does not depend on the existence of exposed vertical mullions on the wall of the building. Furthermore it does not require the installation of any tracks or rails on the building wall as many proposed devices do (e.g. See also U.S. Pat. No. 7,007,334 B2). 
     SUMMARY OF THE INVENTION 
     Introduction 
     In the present invention the cleaning apparatus is lowered from the building roof and operated by remote control, e.g. with the aid of closed circuit television. The cleaning apparatus is lowered from the building roof and temporarily parked opposite the window glaze to be cleaned. The cleaning operation mimics the conventional manual process used for cleaning low level easily accessible windows. This means that a minimum amount of cleaning fluid is applied and the problem of disposing of excess fluid by suction, or other means, is avoided. The first cleaning operation, that of wetting the window with a washing liquid and scrubbing the window outer glaze surface, is performed in a manner identical to that performed manually by workers outside the window. It makes no difference whether or not the window is recessed from the building outer wall surface. With the present invention the operator is free to give smudged spots on the glaze surface extra scrubbing if required. Such detailed attention is not possible with the prior art devices discussed above. The scrubbing operation is followed by a scraping operation, again, in a manner identical to that carried out conventionally by workers located outside the window. The cleaning tools (e.g. brush and squeegee) are caused to undergo any desired planar motion in the plane of the window, and are rotated as required to work into corners and change cleaning direction. In the present invention the angle of attack between the squeegee blade and the surface to be cleaned remains substantially constant at the desired setting. Also, with the present invention brushes and squeegees of any convenient design or length may be utilized. For example, the squeegee may include replaceable scraping blades and the brush may include a replaceable brush head. They are guided over the entire glaze surface regardless of its geometry, rectangular or otherwise, just as they are in the manual cleaning of low level easily accessible windows. No remote controlled apparatus on the market today has these unique features. 
     According to one embodiment of the invention, a remotely operated high rise building window glaze or building facade cleaning apparatus, comprising a rigid master frame of three-dimensional open-cage rectangular shape, for in operation being placed in a position opposite and adjacent to a surface to be cleaned, an open-cage sub-frame of similar geometry and smaller dimensions, suspended within the master frame in spaced relationship therefrom, a cylindrical insertion tool attached to the sub-frame, such that its axis remains always perpendicular to the surface to be cleaned, including activation means therefor, cleaning tools attached to the insertion tool, including washing liquid spray means, mechanical scrubbing means and mechanical scraping means, wherein the mechanical scrubbing means and mechanical scraping means are rotatable and moveable in any desired planar motion in the plane of the surface to be cleaned, and remote control means for remotely operating the apparatus, such that in operation, the liquid spray means, mechanical scrubbing means and mechanical scraping means are sequentially brought to bear against the surface to be cleaned by said activation means. 
     According to another embodiment of the present invention there is provided a remotely operated high rise building window glaze or building facade, cleaning apparatus comprising, a rigid master frame of three-dimensional open-cage rectangular shape, adapted to be vertically lowered or raised by means of a suspension cable to and from a cleaning position opposite the window glaze or building facade to be cleaned, wherein the open-cage master frame is defined by horizontally disposed upper and lower members joined at respective upper and lower corners by vertically disposed members, and including building wall contact means attached to the inside lower corners to maintain positioning of the master frame in a stationary position during the cleaning operation, an open-cage sub-frame of similar geometry and of smaller dimensions suspended within the master frame in spaced relationship therefrom, wherein the open-cage sub-frame is defined by horizontally disposed upper and lower base members pivotably joined at respective upper and lower corners by vertically disposed members e.g. in the form of circular corner rails, and wherein the lower corners are pin jointed in such a way that in operation the lower base members pivot out from the building facade, thereby forming a parallelogram shape, a rigid two-dimensional rectangular shaped main frame defined by horizontal rails e.g. of circular form, attached at each end to vertical travelling end assemblies fitted with linear bearings, the linear bearings being slideable up and down the vertical corner rails of the sub-frame at the same rate, wherein vertical travel of the bearings is effected by a first drive system e.g. a chain-sprocket drive, the first drive system being so designed that the main frame always travels in a vertical plane, though this plane of travel will be moved horizontally outward from the building facade as the base of the sub-frame pivots outward, a carrier frame slideable horizontally along the main frame by means of linear bearings fitted on the horizontal rails of the main frame, such that horizontal motion of the carrier frame is effected by means of a second drive system e.g. chain-sprocket system mounted on the main frame, a cylindrical insertion tool mounted on the carrier frame such that its axis remains always perpendicular to the surface to be cleaned, including activation means therefor, cleaning tools attached to the insertion tool, including washing liquid spray means, mechanical scrubbing means and mechanical scraping means, such that in operation, the liquid spray means, mechanical scrubbing means and mechanical scraping means are sequentially brought to bear on the surface to be cleaned by said activation means, wherein further increasing the insertion tool travel toward the window glaze causes the sub-frame to move outward at its base thereby increasing the pressure of the mechanical scrubbing means and/or the mechanical scraping means on the surface to be cleaned to a desired level, and remote control means for remotely operating the apparatus. 
     In an embodiment of the invention, the apparatus additionally comprises a pair of coil springs mounted horizontally on the upper members of the master frame connected to a pair of cables, wherein the cables pass over pulleys and downward where they are connected to the main frame, 
     In an embodiment of the invention, the mechanical scrubbing means e.g. a brush or a sponge, and mechanical scraping means e.g. a squeegee, are rotatable and moveable in any desired planar motion in the plane of the surface to be cleaned. 
     In an embodiment of the invention the master frame is moved up and down by a cable e.g by a single cable suspended from a single roof-mounted boom, or by a pair of cables suspended from a pair of roof-mounted booms, its movement being controlled by the remote control means. 
     In an embodiment of the invention, the wall contact means is in the form of pads, to provide intimate sustained contact with the building wall, such that the resulting friction forces maintain the master frame in a steady position during the cleaning operation. It will be appreciated that in some embodiments, the pads could be replaced by wheel assemblies. When pads are used, cantilevered counter weights may be attached to the master frame lower extremities, to increase the pad/building wall interaction forces to further promote steadiness. Similarly, if wheel assemblies are used the same cantilevered counter weights may be employed to increase the wheel assembly/building wall interaction forces 
     In an embodiment of the invention, the pair of cables suspended from the pair of coil springs serve to stretch the springs and exert a vertical lifting force on the main frame substantially sufficient to neutralize the gravitational forces acting on the main frame when it is half way through its vertical travel, thus permitting substantially full vertical travel of the main frame to be effected with a minimum of force from the vertical travel drive chain system. 
     In an embodiment of the invention, the remote control means includes a set of remote station controls for activating two-way electric motors driving the first and second sprocket-chain drives, pressurizing or venting the insertion tool activation means e.g. an air cylinder, activating the liquid spray pump motor, and causing rotation of a two-way electric motor mounted on the insertion tool which provides for rotation of the brush and squeegee. These controls provide for any desired planar motion of the brush and squeegee in the plane of the window surface to be cleaned. While a brush or squeegee may be mounted on the same insertion tool, in a typical embodiment, two insertion tools, one above the other, or one beside the other, are employed, one carrying a brush and the other carrying a squeegee. It will also be appreciated that the liquid spray means and the mechanical scrubbing means may be mounted on the same insertion tool. 
     In an embodiment of the invention, the liquid spray means includes a reservoir for washing liquid and a liquid spray pump associated therewith. 
     In an embodiment of the invention the cleaning operation is monitored by a conventional closed circuit television system with cameras mounted as desired on the carrier frame and the master frame. A television receiver is provided at the remote control station to permit the operator to monitor and control the cleaning process. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the accompanying drawings which illustrate, by way of examples, embodiments of the present invention, 
         FIGS. 1A and 1B  are schematic views of two embodiments of the remote operated window cleaning apparatus in service, 
         FIG. 1C  is a schematic view of the apparatus according to the invention, 
         FIG. 2  is a front view of a master frame with a vertical chain drive in place, 
         FIG. 3  is an end view taken in section along II-II in  FIG. 2 , 
         FIG. 4  is a front view of a parallelogram frame, 
         FIG. 5  is an end view taken in section along III-III in  FIG. 4 , 
         FIG. 6  is a front view of a parallelogram frame suspended inside a master frame, 
         FIG. 7  is an end view taken in section along IV-IV in  FIG. 6 , 
         FIG. 8  is a front view of a vertically travelling main frame with section view of vertically sliding end assemblies, and carrier frame attached, 
         FIG. 9  is an end view of a vertically sliding end assembly, 
         FIG. 10  is a front view taken in section along V-V in  FIG. 9 , 
         FIG. 11  is an end view of a vertical chain drive system used to raise and lower the main frame, 
         FIG. 12  is a plan view of an electric drive system mounted above a master frame for powering a vertical chain drive, 
         FIG. 13  is a plan view of an air-operated insertion tool with squeegee attachment, 
         FIG. 14  is an end view taken in section along VI-VI in  FIG. 13 , 
         FIG. 15  is a plan view of a cleaning brush with liquid spray attachment, 
         FIG. 16  is an end view in section along VII-VII in  FIG. 15 , 
         FIG. 17A  is a section view taken through a remote operated window cleaning apparatus, 
         FIG. 17B  is a section view taken through a remote operated window cleaning apparatus, 
         FIG. 18  is a front view of a master, parallelogram, and main frame assembly showing a vertical lift elastic spring system located along the top of the master frame, and 
         FIG. 19  is a schematic view of a closed circuit television camera mounted on an insertion tool carrier frame. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As seen in  FIG. 1A , the remotely operated building window, or facade cleaning apparatus according to the invention generally shown as  1 , is adapted to be suspended from the rooftop of a building  2  by a boom means  3  or the like mounted on the rooftop, by a cable  4 . In this arrangement, a primary cable  4  is attached to a gathering block  4   a , and four secondary cables  4   b  connect the gathering block  4   a  to the four upper corners of a master frame  5 . 
     In  FIG. 1B , an alternative suspension system is illustrated, wherein a pair of booms  3  are employed. A pair of primary cables  4 , a pair of gathering blocks  4   a  and secondary cables  4   b  connect the gathering blocks  4   a  to the four upper corners of a master frame  5 . 
     It will be appreciated that the apparatus according to the invention may be used to clean windows that are flush or indented from the building facade or the building wall facade itself and the like. 
     The boom means  3  can be adapted to travel along the rooftop eg. on a track (not shown) adjacent to the building wall to facilitate full coverage of the building wall facade. 
     Remote control of the operation of the apparatus according to the invention may be provided by a conventional remote control means(not shown) located in a vehicle, such as a truck  6  shown in  FIGS. 1A and 1B , parked on the ground adjacent to the building. It will be appreciated that the remote location of the control means can be in any convenient location either on the ground, on the roof top or in the building. In some embodiments, a light electric cable  6   a  is used to provide electricity at domestic voltages to the apparatus. However, it is not essential that a direct electrical connection between the apparatus and the electrical power source be employed. In some embodiments, the electric power required to drive the electric motors etc, is provided by batteries e.g. rechargeable batteries carried on the master frame  5 . Similarly, remote control signals may be transmitted to the apparatus by an electric cable, or they may be transmitted by means of a conventional wirelesss system. 
     As best seen in  FIGS. 1C ,  2  and  3 , the novel apparatus according to the invention includes a rigid master frame  5  of three dimensional open-cage rectangular shape for in operation being placed in a position opposite and adjacent to the outer glazed surface  9  of a window to be cleaned. When in position the master frame  5  makes intimate and sustained contact with the building wall  7 , by a wall contact means. In this embodiment, a pair of sliding pads or shoes  5   a  mounted on the lower corners of the master frame  5 . Other contact means such as wheels could also be used. 
     Counter weights  8 , also shown in  FIG. 2 and 3  are employed in some embodiments, to provide additional friction forces between the shoes  5   a  and the building wall  7 , so that motion of the master frame is avoided during the cleaning operation. Also, a thin plastic sheet material may be attached to the shoes in order to increase tangential friction forces between the shoes  5   a , and the wall  7 . 
     In one embodiment, the master frame is defined by horizontally disposed upper and lower members  5   b  joined at respective upper and lower corners  5   c  by vertically disposed members  5   d  (see  FIG. 1C ), wherein the members are made of hollow-square cross-section aluminum bars welded together. 
     As best seen in  FIGS. 1C ,  4  and  5 , the novel apparatus according to the invention includes also a parallelogram sub-frame  13  of three dimensional open cage parallelogram shape for in operation being suspended inside the master frame by means of pinned joints  11  connecting with cross bars  11   a  of the master frame ( FIGS. 4 and 5 ). In one embodiment the upper pairs of horizontal bars  10  of the parallelogram frame  13 , and vertical bars  12  connecting the lower horizontal pairs of bars  14  are of hollow-square cross-section aluminum welded together. Four vertical bars  15  of circular cross-section are connected by rigid clamps  17  ( FIG. 5 ), to the upper and lower pairs of horizontal bars ( FIGS. 4 and 5 ). In some embodiments the vertical bars  15 , may be of hollow steel cross-section. Short horizontal bars  18 , are pin connected to the lower pairs of horizontal bars, at each end of the frame. It will be apparent that with the base of the frame  13   a  caused to move outward from the building wall  7 , the side elevation of the frame will take on a parallelogram configuration ( FIG. 17B ). 
       FIGS. 6 and 7  provide front and end views, respectively, of the assembled master and parallelogram frames. 
       FIG. 8  provides a front view of a vertically travelling two-dimensional rectangular main frame  16 . The main frame  16  is defined by two horizontal circular rails  31  rigidly attached at each end by means of clamps  17   a , to rectangular end frames  27 . A rectangular insertion tool carrier frame  29 , fitted with linear bearings  19 , slides back and forth along the rails  31 . The horizontal motion of the carrier frame  29  is effected by a chain drive system  37 , powered by a remote controlled two directional electric motor  35 , resting on a motor support bracket  36  attached at each end to the main frame  16 . Cross-member  45 , of the carrier frame  29 , provides a base for mounting the insertion tool  64  (see  FIG. 13 ) and window cleaning tools. The main frame  16  is attached at each end to vertically sliding end assemblies  22  ( FIG. 9 ), which are caused to slide along the vertical circular bars  15 , of the parallelogram sub-frame. 
       FIG. 9  provides a view of the vertically sliding end assemblies  22 . Two vertical bars  21 , are fitted at each extremity with linear bearings  19 , which slide along pairs of adjacent vertical circular bars  15 , at each end of the parallelogram sub-frame. Each end assembly  22  is fitted with a linkage bar  23 , which is pin connected to the mid-points of the vertical bars  21 . A thin plate, approximately diamond in shape,  25 , is welded or otherwise rigidly attached to the linkage bar  23 .  FIG. 10  provides a view along V-V of  FIG. 9 . When the main frame of  FIG. 8  is fully assembled, one vertically sliding end assembly  22  ( FIG. 9 ) is rigidly attached to each end frame  27 , of the main frame, along the central vertical axis of the diamond shaped plate. An edge view of the diamond shaped plates  25 , is seen in  FIG. 8 . 
       FIG. 11  presents an end view of the assembled window cleaner apparatus with the vertical chain drive system in place. The extremities of the chain loops of the figure are attached to the ends of the vertical sliding bars  21  of the vertical sliding end assemblies  22  ( FIG. 9 ).  FIG. 12  is a plan view of an electric motor and shaft arrangement used to power the vertical chain drive system of  FIG. 11 . It is located above the master frame and attached to it. It is driven by a two-way remote controlled electric motor  93 . 
     A plan section view of an air operated cylindrical insertion tool  64  for mounting on the insertion tool carrier frame  29  of  FIG. 8  is presented in  FIG. 13 . It is shown with the attachment for squeegeeing  61 , in place. It comprises a horizontal cylinder  63 , with a thin hollow circular tube  65 , passing along its axis. A short piston  67 , is fixed to the hollow tube  65 , and slides with an air seal contacting the inner surface of the cylinder  63 , with air seals also located between the hollow tube  65 , and the end caps of the horizontal cylinder  63 . The cylinder is thereby divided into two phneumatic chambers A and B ( FIG. 13 ). Pressurizing chamber A and venting chamber B causes the thin hollow tube  65 , to advance toward the glaze surface  9  ( FIG. 3 ) in preparation for the window cleaning operation. Pressurizing chamber B and venting chamber A permits withdrawal of the tube  65 . An extension tube  69 , is attached to one end of the horizontal cylinder  63 . A narrow open slot runs along the upper surface of the extension tube. A set screw  71 , passes through this slot and serves to lock an annular ring  73 , against the hollow tube  65 . The set screw  73 , is free to slide back and forth along the slot while preventing rotation of the hollow tube  65 . It may be so located as to limit the insertion depth to which the thin tube  65 , can travel, if desired. A circular cylindrical rod  75 , passes along the axis of the thin tube  65 . It is supported near one end by the bearing  76 , which in turn is attached to the thin tube. A squeegee  61 , is shown attached to the outer end of this rod ( FIG. 13 ). At the other extremity the rod  75 , is supported by a bearing  77 , which in turn is attached to the thin tube  65 . A coupling  79 , connects the rod  75 , to a small remote controlled two-way electric motor  81 , which permits rotation of the squeegee in either direction as desired. The electric motor is supported by a motor mounting clip  83 , attached to a circular ring  85 , the ring being rigidly attached to the thin tube  65 . A window glaze brush with window washing fluid spray attached is shown in  FIG. 15 . This brushing device may be attached to the solid bar  75 , of the insertion tool of  FIG. 13  instead of the squeegee  61 . In normal operation the window glaze will first be scrubbed with the brush and spray facility. Following this operation the glaze will be squeegeed with the squeegeeing tool  61 . In one embodiment two insertion tools ( FIG. 13 ) are mounted on the carrier frame base  45 , of  FIG. 8 . They will either be mounted one-above-the-other, or side-by-side. One insertion tool will be fitted with the squeegee device and the other with the spray and brush attachment ( FIG. 15 ). Each tool will be employed in turn as required, the one not in use being withdrawn to avoid interference with operation of the other. The squeegee  61 , ( FIG. 13 ) may be fitted with an elastic buffer segment  62 , ( FIG. 14 ), if desired, to add flexibility to the squeegee tool. 
     A section view taken through the remote operated window cleaning apparatus with the insertion tool and attached squeegee tool ( FIG. 13 ) mounted on the carrier frame  29 , is provided in  FIG. 17A . The carrier frame rides along the circular bars  31  of the main frame ( FIG. 8 ). In  FIG. 17A  the blade of the squeegee tool  61  has been inserted and brought to bear on the window glaze surface  9 .  FIG. 17B  shows the same apparatus after further inward insertion action (exaggerated here for illustrative purposes). It is seen that as a result of this further insertion action the base  13   a  of the sub-frame ( FIG. 5 ) is caused to pivot outward from the building wall forming a parallelogram shape and thereby increasing the reaction force of the squeegee blade on the glaze surface. This reaction increase is a result of gravitational forces acting on the sub-frame, the main frame, and the insertion tool. The reaction force can be adjusted to the desired level by controlling the degree of insertion imposed by the insertion tool. The required insertion can be reduced by employing counter weights  8  ( FIGS. 2 and 3 ) cantilevered outward from the base of the parallelogram frame. Because of the design of the vertically sliding end assemblies ( FIGS. 9 and 11 ) and the vertical chain drive system ( FIG. 11 ) the axis of the insertion tool will always remain perpendicular to the glaze surface  9 , regardless of the degree of insertion effected by the insertion tool. Furthermore, the angle of contact between the squeegee blade ( FIG. 17A ) and the glaze surface will remain unchanged throughout the window cleaning operation. Rotation of the squeegee is achievable because of the maintained perpendicularity between the axis of the insertion tool and the glaze surface. 
     A vertical lift elastic spring system mounted along the top of the master frame  5 , is shown in  FIG. 18 . It comprises two horizontal coil springs  101 , each anchored at one end to an outer edge of the frame, and with a small cable pulley  103 , attached to the other end. Light cables  99 , ( FIG. 9 ) are also attached to the upper master frame at positions adjacent to the coil spring attachments. Each cable is threaded through the coil spring pulley  103 , at the opposite edge of the frame and then passes back and through another pulley  105 , attached to the master frame ( FIG. 18 ) before descending immediately for attachment to the top of the diamond shaped plates ( FIG. 9 ). These coil spring-cable systems function like similar systems found in conjunction with garage door opener assist systems. By proper choice of coil springs and associated cable lengths the gravitational forces acting on the vertically moving main frame are counteracted and a balance between these gravitational forces and the cable tensions can be achieved when the main frame is about half way up its vertical travel. This results in much less energy being required to effect the demanded vertical travel of the main frame and much lower loading on the elevating chains of  FIG. 11 . 
       FIG. 19  presents a schematic view of a closed circuit television camera  107 , mounted on a bracket attached to the insertion tool carrier frame  29 , ( FIG. 8 ), thus permitting immediate monitoring by the operator of the action of the brushing and squeegeeing tools on the glazed surface. In some embodiments another wide angle lens camera may be attached to the master frame to provide the operator at the remote control station with a global view of the entire window glaze cleaning operation. 
     It will be appreciated that the control means(not shown) would include a conventional console with appropriate controls. In one embodiment, the console includes a commercially available joystick for controlling the electric motors and thus the planar motion of the cleaning tools (brush and squeegee). The same joystick has a rotatable handle which permits simultaneous rotation of the brush and/or the squeegee in either direction as desired. Conventional switches, such a s simple toggle switches mounted on the console mounted on the console permit activation of the washing liquid spray pump and activation of the insertion tool for insertion or withdrawal of the cleaning tools to and from the plane of the surface to be cleaned. Other switches provide for vertical or horizontal movement of the apparatus to and from a position opposite the surface to be cleaned. 
     Because of the anticipated low production cost of the apparatus according to the invention, for practical purposes it is contemplated that they would be custom made to the building and its window dimensions, and could be stored, for example, on the building rooftop until ready for use, although due to the inherent versatility and range of movement capabilities of the mechanical scrubbing and scraping tools, a universal application apparatus is also within the scope of this invention.