US3855658A

US3855658A - Window screen cleaning apparatus

Info

Publication number: US3855658A
Application number: US00411808A
Authority: US
Inventors: F Ford
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-11-01
Filing date: 1973-11-01
Publication date: 1974-12-24
Anticipated expiration: 1991-12-24

Abstract

A window screen cleaning apparatus features a conveyor assembly that automatically through a chain driven push bar arrangement carries the screens through dry brushing, detergent spraying and wet brushing sections of the apparatus. The screens are supported on spaced wires that are mounted under tension along the path of movement and are restricted in their upward movement under the influence of the brushing arrangements utilized by wires that overlie the path of movement and are again tensioned on the apparatus. The brush assemblies used have bristles that project through the adjacent wires and a spring arrangement is provided for maintaining the brushes in suitable operating positions. Provisions are also made for collecting and recycling the detergent solution used in the washing process.

Description

United States Patent [191 Ford [111 3,855,658 [4 1 Dec. 24, 1974 1 WINDOW SCREEN CLEANING APPARATUS [76] Inventor: Francis L. Ford, 1110 Raymond Ave., Fort Pierce, Fla. 33450 22 Filed: Nov. 1,1973 21 Appl. No.: 411,808

3,292,194 12/1966 Randall ..15/77 Primary ExaminerEdward L. Roberts Attorney, Agent, or FirmRoger L. Martin, Esq.

[57] ABSTRACT A window screen cleaning apparatus features a conveyor assembly that automatically through a chain driven push bar arrangement carries the screens through dry brushing, detergent spraying and wet brushing sections of the apparatus. The screens are supported on spaced wires that are mounted under tension along the path of movement and are restricted in their upward movement under the influence of the brushing arrangements utilized by wires that overlie the path of movement and are again tensioned on the apparatus. The brush assemblies used have bristles that project through the adjacent wires and a spring arrangement is provided for maintaining the brushes in suitable operating positions. Provisions are also made for collecting and recycling the detergent solution used in the washing process.

8 Claims, 7 Drawing Figures SHEET 5 0f 5 nnounce an 00 cc oooanc WINDOW SCREEN CLEANING APPARATUS This invention relates to a cleaning apparatus for washing window screens.

It is common practice to provide framed window screens for the windows in homes, motels and other establishments where the need arises to provide a barrier to the passage of insects when the window areas are open to admit fresh air. Such screens need periodic cleaning in order to remove soot, dust and other dirt accumulations that not only render the screens unsightly but also obstruct the passage of air therethrough.

Many of the window screens in use today are made from aluminum wire and the framing components are made from extruded aluminum parts that are relatively fragile and readily bent. When screens are washed by hand it is a common practice to brush both side faces of the screen with a brush that has been dipped in a suitable detergent solution and when screens of the aforementioned type are cleaned in this manner it is not infrequent that the mesh wires are broken and the framing components are bent or otherwise damaged. Such damage can usually be attributed to careless practices indulged in by the worker in manipulating the screen in order to brush both side faces thereof and who not infrequently fails to adequately support the screen when the side face is being brushed. Apart from this, the procedures followed in hand cleaning such screens with detergent solutions lead to the waste of such solutions. For one the usual worker in mixing up aqueous detergent solutions will usually use in excess amounts of detergents with the thought in mind that the excess will make the job easier to perform. Secondly, the detergent solution used in hand procedures for cleaning such window screens is lost as run off from the work area.

A general object of the invention is to provide an improved window screen cleaning apparatus. One particular object is to provide an apparatus of the type contemplated which minimizes the amount of handling to which the window screens are subjected during the cleaning procedure. Yet another object is to provide an apparatus of the type contemplated which permits the efficient and economical use of detergent containing solutions in the cleaning of such window screens. Yet another object is to provide an apparatus of the type contemplated which may be assembled from conventional and standard off the shelf parts and components.

In accord with the invention, a set of spaced wires that are mounted under tension on a frame are used to support the window screens as they are conveyed through brushing and spraying sections of the apparatus and another set of spaced wires that are mounted under tension on the frame are utilized to resist upward 'movement of the screens under the influence of a brushing action that transpires at the underside faces of the screens during their conveyance through the apparatus. Brush assemblies that respectively overlie and underlie the path traversed by the Window screen through the apparatus have bristles which project through the spaces between the wires and into contact with the opposite side faces of the screens and these brush assemblies are pivotally movable and equipped with a spring biasing arrangement that resists pivotal movement of the brushes out of their operating positions in the apparatus arrangement. Provisions are made in the apparatus for brushing the screens before they are subjected to a spray of detergent containing solution so as to dislodge dirt that would otherwise consume detergent if removed and suspended in the recycled detergent solution system used in the apparatus, and subsequent to the spraying operation, the screens are again subjected to a brushing action that removes reusable detergent solution that is captured in the meshes of the screens.

The novel features which are believed to be characteristic of this invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and method of operation, together with further objects and advantages thereof may best be understood by reference to the following description taken in connection with the accompanying drawings, in which:

FIG. 1 is a side elevational view of a washing apparatus embodying the principles of the invention, certain parts being broken away;

FIG. 2 is a plan view of the apparatus seen in FIG. 1 with certain parts broken away;

FIG. 3 is a transverse vertical section view taken generally along the Lines 33 of FIG. 1;

FIG. 4 is a vertical sectional view of a fragment of the apparatus seen in FIG. 1 and as taken along the longitudinal axis of the apparatus;

FIG. 5 is a vertical sectional view of another fragment of the apparatus seen in FIG. 1 as taken along the longitudinal axis of the apparatus;

FIG. 6 is a side elevational view of a fragment of the apparatus seen in FIG. 1 as seen in association with a frame supported rinse tank or tray to which the washed screens are fed from the apparatus; and

FIG. 7 is an elevational section view of a fragment of the frame supported rinse tank or tray shown in FIG. 6 as seen along the Lines 77 therein.

Reference is now made to the drawings and wherein a cleaning apparatus embodying the principles of the invention and which is used for washing window screens is generally designated at 10. It includes a conveyor mechanism 11 for conveying or moving the window screens 12 along a horizontal path 13 of movement that extends from a screen receiving station 14 to a screen delivery station 15. Mechanism 11 is mounted on an elongated rigid frame 16 that is of generally open construction and which has

opposite ends

17 and 18 and

opposite sides

19 and 20.

The window screens that are cleaned in the operation of the apparatus 10 have a wire mesh 24 which is mounted in an open rectangular frame 25 and as the flat screens are conveyed through the apparatus they are oriented in a horizontal position and supported on a first set 26 of wires 27 that extend longitudinally of the frame and underlie and define the path of movement 13 of the screens 12 through the apparatus.

As the screens pass through the apparatus they first enter a dry brushing section 29 where the upper and lower side faces 30 and 31 of the screens are subjected to a brushed action by a set 32 of brush assemblies 33 so as to dislodge dirt and other debris that is clinging to the screens 12. This dirt and debris is collected in a box-like tray 34 which underlies the dry brushing section 29. Following the brushing treatment in the dry brushing section, the screens 12 pass through a spraying section 36 that is equipped with a spray mechanism 37 for spraying an aqueous detergent solution onto the screens. This section 36 is also equipped with another set 38 of brush assemblies 33 and which here subject the upper and

lower faces

30 and 31 of the screens to a second brushing action as the solution is being sprayed onto the screens.

Following the cleaning treatment that transpires in the spraying section 36, the screens pass through a wet brushing section 42 that is equipped with another set 43 of brush assemblies which serve to dislodge residual dirt but more importantly, serve to break the surface tension of the solution which remains in the meshes of the wire meshes 24 so that this residual solution that clings to the mesh 24 can be recovered in the underlying detergent collection system. In this respect, the apparatus is equipped with a means for collecting or recovering the sprayed solution and which includes a trough 45 that is located below the path of movement of the screens through the spray section 36 and wet brushing section 42. The detergent containing solution which falls into this trough 45 is delivered by a discharge pipe 46 to a reservoir 47 that is ground supported on chocks 48, as seen in FIG. 3.

It will be apparent that the brushing action which transpires in

sections

29, 36 and 42 tends to dislodge the screens from their supported positions on the support wires 27 and to resist upward movement of the window screens for reasons of their contact with the brush assemblies in these sections, the apparatus 10 is equipped with a second set 50 of wires 51 that extend longitudinally and like the wires 27 of the first set 26 are mounted under tension on the frame 16. As best seen in FIG. 3, 4 and 5, the screen supporting wires 27 are mounted in a common horizontal plane and are spaced apart in a parallel arrangement. The wires 51 of the second set 50 are similarly mounted in a common plane in which they are spaced apart and arranged in parallel. As thus arranged they overlie the path 13 of movement for the screens and with the support wires 27 define an elongated narrow screen confining passageway 53 along the path of movement for the screens that basically limits vertical movement of the horizontally arranged flat screens as they are conveyed from the feed end 54 to the discharge end 55 of the passageway 53.

Frame 16 includes upright corner posts 58 that are located at the

opposite ends

17 and 18 of the frame and these posts 58 are fixed to and support longitudinally extending opposite side rails 59 in the frame structure. The posts 58 and rails 59 at the feed end 17 of the frame are braced by angles 60 and the frame is equipped with a pair of longitudinally extending angles 61 that are located at the opposite sides 19 and of the frame and fixed at their opposite ends to the comer posts. These angles 61 serve as supports for the lower flight for the chain components of the conveyor mechanism 11 as will be subsequently seen and between the opposite ends of the frame are fixed to upright side posts members 62 of the frame structure.

The top side rails 59 of the frame are rigidly interconnected by a plurality of longitudinally spaced and transversely arranged tubular members designated at 63. These members 63 serve to support the horizontally spaced wires 27 which in turn support the screens 12 that are being conveyed through the apparatus. As seen in FIG. 5, these wires 27 are bent around the tubular members 63 at the discharge end 18 of frame 16 and are here securely tied to a transversely extending angle member 64 that is welded at its opposite ends to the top side rails 59. The wires 27. are similarly bent around the tubular members 63 at the feed end 17 of the frame but here the wires are securely fastened to respective hooks 65 that are mounted on a transversely arranged angle 66 that is fixed to the top side rails 59. These hooks 65 are adjustably mounted on the angle member 66 by means of thread engaging nuts that permit the wires to be adjustably tensioned on the frame structure.

Between the receiving and

delivery stations

14 and 15, the top side rails 59 are each equipped with a longitudinally extending angle member 67 that provides a mounting piece for a longitudinally extending wooden side board 68 that is used in mounting the brush assemblies that are located above the path of movement 13 for the screens 12. Adjacent the delivery station 15 the frame 16 has a transversely extending metal plate 69 that is welded at its opposite ends to the side angles 67 and here the frame, as seen in FIG. 5, is provided with a transversely extending horizontally arranged tubular member 71 and additionally with a transversely extending angle member '70 that is welded to the plate. The wires 51 of the second set 50 are bent around the tubular member 71 and tied to the angle as seen in FIG. 5. At their opposite ends, these wires 51 (see FIG. 4) are bent around yet another tubular member 72 that extends transversely of the frame and is fixed to the angle 67. Here the wires 51 are tied to respective hooks 73 that are adjustably mounted on a transversely arranged angle 74 that is supported at its opposite ends by means of inclined members 75 which are Welded to angles 67 at the opposite sides of the frame.

In addition to the side boards 68, the frame 16 is equipped with another pair of elongated, longitudinally extending side boards 76 which extend below and are mounted on the top side rails 59. These boards are used in mounting the brush assemblies 33 that are located below the path of movement for the screens while the side boards 68 are used for mounting the brush assemblies 33 that are located above the path of movement for the screens.

The structure of the brush assemblies is best seen by reference to

assemblies

78 and 79 and which are located, as seen in FIGS. 3 and 5, respectively above and below the path of movement. Each brush assembly is a generally elongated structure which is mounted in a manner such as to extend transversely of the path of movement of the screens and comprises an elongated wooden member 81 that serves as a mounting piece for a plurality of brushes 82. Each of the assemblies is mounted for pivotal movement about a horizontal pivot axis that extends transversely of the frame and is secured by fasteners 83 to an elongated angle member 84 that is fixed to an elongated tubular member 85. The tubular member 83 for the brush assemblies that overlie the path of movement of the screens is mounted in transversely aligned holes 86 in the upper side boards 68 of the frame structure as exemplified by the mounting arrangement for brush assemblies 78. On the other hand, the tubular members for the brush assemblies which are arranged to underlie the path of movement are pivotally mounted in aligned holes 87 in the under side board members 76 of frame 16 as exemplified by the mounting arrangement for brush assemblies 79.

The brush assemblies 33 in each section are arranged in pairs with one assembly overlying the path of movement and another assembly underlying the path of movement as exemplified by the arrangement for

assemblies

78 and 79. The assemblies of each pair are maintained in appropriate operating positions by means of a coiled tension spring 88 which is located at the right side of the frame 16 and connected at its opposite ends by means of clamps 89 to the tubular members in which the brush assemblies are pivotally mounted.

Brush assemblies

78 and 79, as seen in FIGS. 3 and 5, have operating positions in which the bristles 90 of assembly 78 project downwardly through the spaces between the wires 51 and at which the bristles 91 of assembly 79 project upwardly through the spaces between wires 27. The springs 88 which interconnects these

assemblies

78 and 79 through the pivotally movable members 85 tend to maintain the assemblies in their operating position and serve as yieldable means for resisting pivotal movements, as for example in the direction of arrows 92 out of their operating position. Each tubular member 85 is also equipped with a radially extending element 93 that is arranged to engage an appropriately positioned stop 94 that is mounted in the adjacent side board to limit pivotal movement of the brush assemblies in the direction opposite to that indicated by arrows 92.

The spray mechanism 37 comprises a transversely arranged pipe 96 that is supported at its opposite ends by the upper side boards 68 and which serves as a feed header for a plurality of orifices 97 that are arranged to project sprays of the detergentsolution generally downwardly and through the spaces between the wires 51 and thus onto the screens that are located in the spray section 36. This header is connected by a conduit 99 to the discharge end of a pump 100 that is driven by electric motor 101. The intake of pump 100 is connected by a feed conduit 102 which connects with the reservoir 47 so that the sprayed detergent containing solution is constantly recycled in the operation of the apparatus 10. Thus as the solution is sprayed from the orifices 97 it is gathered in the trough 45 and fed by pipe 46 to the reservoir for collection purposes and subsequent recycle to the spray head. The trough 45 as best seen in FIGS. 1 and 3 is equipped with side brackets 103 and is suspended beneath

sections

36 and 42 by means of interlocking eyebolts 104. These eyebolts, as seen in FIG. 3, are suspended from the top side rails 59 of the frame structure and are releasably fastened to the rails and brackets by means of appropriate nuts. Tray 34 is also releasably suspended from the frame and as seen in FIG. 1, this is accomplished through the use of standard hook elements that are mounted in the lower side boards 76 and engaged appropriately positioned eye elements 106 that are mounted in the opposite sides of the tray.

The conveyor mechanism 11 includes a pair of endless chains 107 that are spaced apart and located at the opposite sides of the frame 16. The chains 107 are interconnected by a plurality of elongated push bars or elements 108 that extend transversely of the frame and are spaced apart to accommodate reception of the screens to be washed in the spaces therebetween. The push bars 108 are carried by and movable with the chains and each chain is mounted so that the upper and lower flights or runs 109 and 110 thereof are vertically aligned in the apparatus. Each chain 107 is mounted on a pair of vertically spaced idler sprockets 111 that are located at the feed end 17 of the frame and at the discharge end 18 of the frame, each chain is driven by a drive sprocket 112 that is fixed to a drive shaft 113. At the left side 19 of the frame shaft 113 is fixed to a chain driven sprocket 114 that is driven by means of a chain 115 that engages a sprocket 116 that is mounted on a shaft of a belt driven pulley 117 of a speed reducing arrangement that includes a second belt driven pulley 118 that is mounted on a shaft carrying a drive pulley coupled by means of a belt 120 to pulley 117. Pulley 118 is in turn driven by a belt 121 that is driven by means of an electric motor 122. Motor 122 and the speed reducing pulley arrangements are mounted on a support plate 123 that is fixed to the frame at the discharge end 18, as generally seen in FIGS. 1 and 3.

When the motor 122 is energized the upper flights 109 of the chains 107 are drawn in the direction of arrow 124 and this carries the transversely arranged push bars 108 along the path of movement for the screens and in sliding contact with the wires 27. As such, they encounter the frames 25 of the screens 12 that are fed to the receiving station 14 and push the screens in sliding contact along the wires 27 to the delivery station at the opposite end of the frame. Here at the delivery station they are discharged from the cleaning apparatus 10 and into a rinse tank or tray 127 that is supported ona table-type framework 128 in a position to receive the screens. The rinse tank as seen in FIG. 7 comprises a bottom wall 129 and side walls 130 which may be made of wooden members that serve to support a Water impervious sheet 131 of suitable material such as sheet polyethylene.

In the operation of the apparatus,

motors

122 and 101 are initially energized to place the conveyor mechanism and spray mechanism in operation. Thereafter the screens to be washed are fed one at a time to the screen receiving station 14. Here each screen is placed in the space between the push bars 108 and supported upon the supporting wires 27 so that the push bar during the movement of the conveyor mechanism encounters the frame 25 of the screen 12 and pushes it along the path 13. As each screen encounters the set 32 of brush assemblies in the dry brushing section, a substantial amount of the dirt, dust and other debris clinging to the screens is removed and collected in the underlying tray 34 and thereafter as the screens are pushed through the spray section 36 the screens are washed with the detergent solution and simultaneously brushed by the second set 38 of brushes. Here the remaining dirt and debris is loosened by the wet brushing action which transpires and suspended in the solution by means of the detergent contained therein. This solution, of course, is collected in the underlying trough 45 and delivered to the reservoir. Thereafter the screens pass through the wet brushing section 42 and the third set 43 of brushes encounter the wire meshes 24 and serve to remove residual dirt and solution that clings to the wire meshes 24. Following the transportation through the wet brushing section 42 the screens are delivered at the delivery station 15 to the rinse tank or tray 127 and from which they are hand removed for drying purposes.

While only certain preferred embodiments of this invention have been shown and described by way of illustration, many modifications will occur to those skilled in the art and it is, therefore, desired that it be understood that it is intended herein to cover all such modifications as fall within the true spirit and scope of this invention.

What is claimed as new and what it is desired to secure by Letters Patent of the United States is:

1. A cleaning apparatus for washing generally flat, framed window screens that have opposite side faces and which comprise an elongated rigid open frame that has opposite ends, a conveyor mechanism mounted on said frame for conveying the window screens along a horizontal path of movement which extends from a screen receiving station located at one of said ends to a screen delivery station located at the other of said ends, a first set of spaced apart and longitudinally extending wires which are mounted in a common plane under tension on said frame and which underlie and define said path of movement for supporting the flat screens in generally horizontal positions as they are conveyed along said path by said mechanism, an elongated brush assembly which is mounted of said frame and which generally underlies and extends transversely of said path of movement for brushing the underside face of the window screens that are conveyed along said path by said mechanism, said assembly having bristles and an operating position at which said bristles project upwardly through the spaces between said wires, a second set of spaced apart and longitudinally extending wires which are mounted in a common plane under tension on said frame and which overlie said path for resisting upward movement of the window screens during contact with said bristles, and a spray mechanism for spraying an aqueous detergent solution onto the window screens that are conveyed along said path by said conveyor mechanism, said spray mechanism comprising a header mounted on said frame and having a plurality of orifices arranged to project sprays of the detergent solution through the spaces between the wires of said second set, means for collecting detergent solution projected by said orifices including a trough mounted on said frame and located below said path of movement, and means for recycling the collected detergent solution to said header.

2. A cleaning apparatus in accord with claim 1 where said header is generally located along said path between said brush assembly and said delivery station.

3. A cleaning apparatus in accord with claim 1 where said brush assembly is generally located along said path between said header and said delivery station.

4. A cleaning apparatus in accord with claim 1 where said brush assembly is mounted for pivotal movement on said frame about a pivot axis that generally extends transversely of said path of movement, and where said apparatus comprises yieldable means connected to said brush assembly for resisting pivotal movement of the assembly out of its operation position.

5. A cleaning apparatus in accord with claim 1 where said apparatus comprises another elongated brush assembly which is mounted on said frame and which overlies and extends transversely of said path of movement for brushing the upper side faces of the window screens that are conveyed along said path by said conveyor mechanism, the brush assembly overlying said path having bristles and an operating position at which the bristles thereof project downwardly through the spaces between the wires of said second set.

6. A cleaning apparatus in accord with claim 5 where each of the brush assemblies is mounted for pivotal movement on said frame about respective pivot axes that are parallel and generally extend transversely of said path of movement, and where said apparatus com prises yieldable means interconnecting said brush assemblies for resisting pivotal movements of the assemblies out of their respective operating positions.

7. A cleaning apparatus in accord with claim 1 where said frame has opposite sides, where said conveyor mechanism comprises a pair of endless chains that are spaced apart and respectively located at said opposite sides, means for driving said chains, and transversely extending elongated push bars interconnecting said chains and movable therewith, said chains being drivingly mounted on said frame and arranged to carry said push bars along said path between said first and second sets of wires, and said push bars being arranged to engage a framed window screen at said receiving station and to push the engaged window screen along said path and in sliding contact with the wires of said first set to said screen delivery station.

8. A cleaning apparatus for washing generally flat, framed window screens that have opposite side faces and which comprise an elongated open, rigid frame having opposite sides and opposite ends, a first set of wires mounted under tension on said frame and defining an elongated horizontal path of movement for the screens and which extends from a screen receiving station located at one of said ends to a screen delivery station location at the other of said ends, said wires being horizontally spaced apart in a parallel arrangement and extending longitudinally of the frame for supporting the screens horizontally during their movement along the path, a conveyor mechanism for moving screens received at said receiving station along said path to said delivery station, said conveyor mechanism including a pair of driven endless chains that are spaced apart and drivingly mounted at said opposite sides respectively, a plurality of elongated elements that are spaced apart and arranged transversely of the frame in the space between said chains, and means for continuously driving said chains; said elongated elements being connected to each of said chains and movable therewith, said chains having respective flights arranged to move said elongated elements along said path and in sliding contact with said wires when said chains are driven by the driving means therefor, a second set of wires that are mounted under tension on said frame and overlie said path of movement, the wires of said second set being horizontally spaced apart in a parallel arrange ment and extending longitudinally of said frame, the wires of said second set being located above and spaced apart from the wires of said first set to therewith define a narrow screen confining passageway along said path of movement, said passageway having a feed end located between said receiving station and said delivery station; a first set of brush assemblies mounted on said frame at said feed end of said passageway, a second set of brush assemblies mounted on said frame between said first set of brush assemblies and said delivery station, a third set of brush assemblies mounted on said frame between said second set of brush assemblies and said delivery station, each of the sets of brush assemblies comprising a first elongated brush assembly which generally underlies and extends transversely of said path of movement for brushing the underside faces of the window screens, and a second elongated brush assembly which generally overlies and extends transversely of said path of movement for brushing the upper side faces of the window screens, said first elongated brush assembly having bristles and an operating position at which the bristles project upwardly through the spaces between the wires of said first set of wires, said second elongated brush assembly having bristles and an operating position at which the bristles project downwardly through the spaces between the wires of said second set of wires, a tray mounted on said frame beneath said first set of brush assemblies for collecting dirt dislodged by the brush assemblies thereof, a spray mechanism for spraying an aqueous detergent solution onto window screens located in the passageway at said second set of brush assemblies, said spray mechanism comprising a header mounted on said frame between said first and third sets of brush assemblies and having a plurality of orifices arranged to project sprays of the aqueous detergent solution through the spaces between the wires of said second set of wires, means for collecting the aqueous detergent solution projected by said orifices including a trough, and means for recycling the collected detergent solution to said header, said trough being mounted on said frame and located beneath said header and said second and third set of brushes assemblies, each of the first and second elongated brush assemblies being mounted for pivotal movement about a respective pivot axis that are parallel and extend transversely of said path of movement, and each of the sets of brush assemblies having yieldable means associated therewith and interconnecting the first and second elongated brush assemblies thereof for resisting pivotal movement of the assemblies out of their respective operating positions.

Claims

6. A cleaning apparatus in accord with claim 5 where each of the brush assemblies is mounted for pivotal movement on said frame about respective pivot axes that are parallel and generally extend transversely of said path of movement, and where said apparatus comprises yieldable means interconnecting said brush assemblies for resisting pivotal movements of the assemblies out of their respective operating positions.

8. A cleaning apparatus for washing generally flat, framed window screens that have opposite side faces and which comprise an elongated open, rigid frame having opposite sides and opposite ends, a first set of wires mounted under tension on said frame and defining an elongated horizontal path of movement for the screens and which extends from a screen receiving station located at one of said ends to a screen delivery station location at the other of said ends, said wires being horizontally spaced apart in a parallel arrangement and extending longitudinally of the frame for supporting the screens horizontally during their movement along the path, a conveyor mechanism for moving screens received at said receiving station along said path to said delivery station, said conveyor mechanism including a pair of driven endless chains that are spaced apart and drivingly mounted at said opposite sides respectively, a plurality of elongated elements that are spaced apart and arranged transversely of the frame in the space between said chains, and means for continuously driving said chains; said elongated elements being connected to each of said chains and movable therewith, said chains having respective flights arranged to move said elongated elements along said path and in sliding contact with said wires when said chains are driven by the driving means therefor, a second set of wires that are mounted under tension on said frame and overlie said path of movement, the wires of said second set being horizontally spaced apart in a parallel arrangement and extending longitudinally of said frame, the wIres of said second set being located above and spaced apart from the wires of said first set to therewith define a narrow screen confining passageway along said path of movement, said passageway having a feed end located between said receiving station and said delivery station; a first set of brush assemblies mounted on said frame at said feed end of said passageway, a second set of brush assemblies mounted on said frame between said first set of brush assemblies and said delivery station, a third set of brush assemblies mounted on said frame between said second set of brush assemblies and said delivery station, each of the sets of brush assemblies comprising a first elongated brush assembly which generally underlies and extends transversely of said path of movement for brushing the underside faces of the window screens, and a second elongated brush assembly which generally overlies and extends transversely of said path of movement for brushing the upper side faces of the window screens, said first elongated brush assembly having bristles and an operating position at which the bristles project upwardly through the spaces between the wires of said first set of wires, said second elongated brush assembly having bristles and an operating position at which the bristles project downwardly through the spaces between the wires of said second set of wires, a tray mounted on said frame beneath said first set of brush assemblies for collecting dirt dislodged by the brush assemblies thereof, a spray mechanism for spraying an aqueous detergent solution onto window screens located in the passageway at said second set of brush assemblies, said spray mechanism comprising a header mounted on said frame between said first and third sets of brush assemblies and having a plurality of orifices arranged to project sprays of the aqueous detergent solution through the spaces between the wires of said second set of wires, means for collecting the aqueous detergent solution projected by said orifices including a trough, and means for recycling the collected detergent solution to said header, said trough being mounted on said frame and located beneath said header and said second and third set of brushes assemblies, each of the first and second elongated brush assemblies being mounted for pivotal movement about a respective pivot axis that are parallel and extend transversely of said path of movement, and each of the sets of brush assemblies having yieldable means associated therewith and interconnecting the first and second elongated brush assemblies thereof for resisting pivotal movement of the assemblies out of their respective operating positions.