WO1992010614A1

WO1992010614A1 - A sweeping machine

Info

Publication number: WO1992010614A1
Application number: PCT/SE1991/000842
Authority: WO
Inventors: Owe Westin
Original assignee: Owe Westin
Priority date: 1990-12-10
Filing date: 1991-12-06
Publication date: 1992-06-25
Also published as: SE9003923D0; SE9003923L; SE506677C2; AU9016091A

Abstract

This invention relates to a machine (10) for cleaning streets, pedestrian precincts and other outdoor areas, and also indoor areas, and comprises a machine body which is carried on support wheels (11, 15, 16), at least two rotatable, driven ground-contacting brush devices (e.g. 22, 23), means (38) for taking-up the rubbish gathered by the rotating brushes, and means (e.g. 32) for spraying liquid on the surface to be cleaned in the region of the rotating brushes. According to the invention, the area in which the rotating brushes are located is open substantially only at the bottom thereof, and in that the liquid is delivered in the form of a mist from at least one nozzle (32) and in a manner such that upon exiting from the nozzle, the liquid will be spread approximately radially and preferably through 360°.

Description

A Sweeping Machine

The present invention relates to a machine for cleaning streets, pedestrian precincts and other open- air spaces as well as indoor spaces. The machine comprises a wheel-supported machine body, at least two rotatably- driven ground-contacting brush means, means for picking up the rubbish collected by the rotating brushes, and means for spraying liquid onto the surface to be cleaned, in the region of the rotating brushes.

Sweeping or cleaning machines of this kind are well known to the art and belong to the so-called self-pickup type of machine, i.e. a machine in which the ground- contacting, rotary brushes coact either with a rubbish elevator means, which conveys the rubbish to an empti- able container, or a machine which incorporates a vacuum cleaner function.

By the word "rubbish" is meant gravel, sand, road dust, paper and cans, among other things, but is also meant to include larger types of rubbish, such as branches and the like from trees and bushes. A machine which is used to clean environments of such rubbish is subjected to a great deal of wear and strain, due to the varying nature of the rubbish, among other things. A constantly recur¬ ring problem with machines of this kind resides in the very large clouds of dust that are created by the rotat- ing brushes as the machine moves forward. This dust has a negative influence on the surroundings and may often present a traffic hazard, since it greatly reduces visibility in the working area of the machine. The environment in which the machine operator works is also highly unsatisfactory. The fact that such dust generation creates a serious problem is evidenced by the extremely large number of patent publications in which different solutions to the problem are proposed.

Prior Art

Each of the Publications Nos. SE 432.455 and 392.493 teaches a method in which a sweeping machine of the aforesaid kind embodies the dust and dust-containing -rubbish lying on the ground in a layer of foam. The same technique is used in principle with the sweeping machines described and illustrated in DE-A-20 37 425 and DE-A-12 17 342.

In practice, however, the foam lies on the surface of the rubbish to be collected and a gap which contains dust quantities is always present between the rubbish and the ground surface. When the ground to be cleaned is heaped with sand and gravel, the foam will lie on the tops of these heaps. When the rotating brushes come into contact with the rubbish, dust clouds are unavoid¬ ably created by the underlying rubbish which has not been sprayed. This dust addition, together with the volume of dust accumulated in the aforedeεcribed manner presents a problem which is still unsolved. The fact that the problem still remains unsolved, despite the solutions proposed in the aforedescribed prior art publications, is evidenced by the fact that the type of sweeping machine normally used at present is of the kind equipped with conventional nozzles for spraying the ground with water. It is a well known fact that water is unable to penetrate dust layers and bind the dust present to any great extent.

With these problems in mind and having knowledge of the known prior art in this field, the primary object of the invention is to provide a sweeping machine of the kind described in the introduction which includes means which, when the machine is used, will keep the dust generated to an acceptable level.

This object is achieved by means of the sweeping machine defined in the preamble of Claim 1 and having the char¬ acteristic features set forth in the characterizing clause of said Claim.

The inventive solution has been found to reduce the dust clouds generated by the rotating brushes by on average 70% in comparison with the amount of dust that is gener¬ ated by conventional sweeping machines.

It will therefore be understood that the inventive solution can be applied to existing sweeping machines, as well as being embodied in the novel improved machine constructed in accordance with the invention and de- scribed by way of example herebelow. By enclosing the space on which the brush devices are located, the dust generated by the brushes will not escape to the area surrounding the machine to any great extent, and by spraying liquid in mist form onto the dust within said enclosed space, through one or more nozzles, in accor¬ dance with the claimed method, the dust particles which swirl in the air within said space will be bind to the liquid mist droplets, at the same time as the mist set¬ tles on the underlying ground surface. Thus, the dust volume swirled-up as the brushes rotate is effectively dealt with by the per¬ manent humidity of the air prevailing within the essen¬ tially closed space in which the brush devices rotate, despite the moisture on the underlying ground surface.

In order to ensure that the substantially closed space will be moisturized as quickly as possible, the liquid- spraying nozzles are preferably mounted above the brush device or brush devices.

According to one preferred embodiment of the invention, the machine includes a flexible and wear-resistant plate-like element or cowling which extends down sub¬ stantially into contact with the ground and which is intended to surround the whole or the greater part of the outside of the ground-contacting, rotating brushes, thereby to provide the aforesaid desired space enclosure which is essentially open only at the bottom thereof. The top of the space can be defined, for instance, by the machine body.

Because the sheet-like cowling is flexible, it can be readily flexed to one side, so as to enable the brush devices to be inspected, for instance.

The nozzle or nozzles through which the liquid mist is sprayed may be a conventional, rotating nozzle. Such nozzles are not only expensive but also require the provision of an expensive drive source. The nozzles also become heavily worn.

It is therefore proposed that the inventive sweeping machine is fitted with a conventional jet nozzle provid¬ ed with simple means which will allow the liquid to be distributed in a direction at about 90° to the direction of the liquid jet when passing through the nozzle ori¬ fice and which will finely divide the liquid jet into the desired mist form. This solution is simpler, more robust and much less expensive than a rotating nozzle and, as distinct from a rotating nozzle, requires no individual drive source. Other advantages and features of the improved sweeping machine will be evident from the depending Claims and from the following description and the associated drawings.

The inventive concept according to which the improved sweeping machine is constructed will now be described in more detail with reference to a preferred exemplifying embodiment thereof illustrated in the accompanying drawings.

Figure 1 is a perspective view of the preferred embodi¬ ment of the improved. Inventive sweeping ma¬ chine; Figure 2 is a schematic side view of the machine shown in Figure 1, with the side covering of the machine having been removed for illustrative purposes; Figure 3 is a schematic view of the sweeping machine shown in Figures 1 and 2 as seen from beneath;

Figure 4 illustrates a preferred embodiment of the elevator belt; and Figure 5 illustrates a preferred embodiment of a nozzle which functions to produce a liquid mist.

The improved, inventive sweeping machine illustrated in Figure 1 is identified generally by the reference numeral 10. The machine 10 has a chassis which is sup¬ ported on a front support wheel 11 which is rotated about an axle 13 by means and held between the legs of a fork 12 and is also rotatable or pivotable about a vertical axle 14. The supporting wheel 11 is mounted centrally in relation to two rear supporting wheels 15, 16, of which only the wheel 15 is shown in Figure 1. The two supporting wheels 15, 16 are rotated and pivoted in a manner similar to the front supporting wheel 11. The arrow A indicates the forward direction of movement of the machine 1.

As will be seen from Figure 1, the machine 10 is also provided with side covers, of which one cover 17 is shown in Figure 1. The side cover 17 may be made of sheetmetal or some other appropriate material. Fitted onto the top of the machine 10 are hinged inspection doors 18, 29, 20. A main control unit is referenced 21. Rotatable brush devices 22, 23 of a known kind are mounted on both sides of the front, centrally mounted supporting wheel 11. As shown in Figure 1, each brush device 22, 23 has a first cover element or cowling 24, 25, made of sheetmetal or some other appropriate material. Mounted on the rear end of the machine is a refillable liquid tank 26.

A preferred embodiment of the brush devices included in the machine 10 is shown in Figure 3, to which reference is now made. The driven, circular brush devices 22, 23 each rotate about a respective axle 27 and 28, and the conventionally designed brushes are intended to engage the ground surface to be cleaned resiliently, and a means is provided whereby the ground-contacting pressure can be adjusted. The brush devices 22, 23 rotate to¬ wards one another in a conventional manner, as indicated by the arrows B, and consequently gather a string of rubbish therebetween. When seen in the forward movement direction of the machine 10, there is provided behind the brush devices 22, 23 a third brush device 29 which is driven for rotation about a horizontal axle 30. The brush device 29 has an elongated configuration and extends in the transverse direction of the machine 10 and is positioned approximately midway along the machine 10. The axial extension of this third brush is such that its active brush surface will extend into the region of the respective forward brush devices 22, 23. The rotational direction of the brush device 29 is shown by the arrow C in Figure 2 and the purpose of said brush device is to move the string of rubbish located between the two front brush devices 22, 23 to a rubbish elevator described herebelow. The pressure at which the brush device 29 contacts the underlying ground surface can also be adjusted.

According to one aspect of the inventive concept, the space within which the brush devices 22, 23 and 29 work is sealed against the surroundings to the best possible extent, so that the dust swirls created by the brush devices as the machine 10 works will remain within said space and the dust particles bound to the mist droplets to the best possible extent. In the case of the illus¬ trated embodiment, this is effected by means of a plate¬ like, flexible and wear-resistant skirt 31 which is attached to the bottom edge of the machine cowling and extends substantially down into contact with the ground. The extension of the skirt 31 in the longitudinal direc¬ tion of the machine 10 will best be seen from Figure 3, the extension of said skirt 31 being shown in lines which are heavier than the remaining contour lines drawn in the Figure.

When viewing Figures 1 and 3 together, it will be seen that the skirt 31 forms a side guard for all brush devices and also a front guard between the circular, rotating brushes 22, 23. The space essentially enclosed by the skirt 31 is defined at the top thereof by the rubbish collecting container, the rubbish elevator and body parts of the apparatus. In the case of the embodi¬ ment illustrated in Figures 1 and 3, a side part of respective front brush devices 22, 23 has been left unskirted, so that the brushes are able to sweep along the bottom of curb stones. It will be understood, however, that the skirting 31 may be extended in the manner illustrated in broken lines in Figure 3, i.e. so that the skirt fully covers the outer side parts of the brush devices 22, 23.

According to another, important aspect of the invention, the primary object of preventing or reducing the cre¬ ation of dust within the aforedescribed, substantially closed space in the region of the brush devices

22, 23, 29 is achieved by providing means which function to produce a liquid mist. Accordingly, the machine is equipped with a liquid tank 26, which contains prefer¬ ably ordinary water. The liquid is delivered under pressure through pipes (not shown) which discharge into vertically arranged nozzles 32. The number of nozzles connected to the tank 26 may be varied. In the pre¬ ferred illustrated embodiment, each of the front rotat¬ able brush devices 22, 23 is fitted with one such nozzle. The nozzles 32 are mounted so as to discharge above respective brush devices, 22, 23 approximately centrally thereof, and are thus relatively highly placed. The nozzles 32 are constructed so as to deliver the pressurized liquid in an extremely finely divided form, a so-called mist form. It should be mentioned here that although the machine may be fitted with con¬ ventionally driven mist nozzles, the inventive machine is fitted with a special inventive nozzle construction, as described in more detail herebelow. It is essential, however, that the liquid mist delivered by the nozzles will moisturize the air present in the substantially closed space, so as to create therein a very high humid¬ ity. Because of the closed nature of the space, this very high humidity will be sustained and the air mois- ture will thus also lie in the form of a mist on the ground surface to be cleaned and therewith also moisten the rubbish effectively. The sustained or constant humidity of the air within said space will bind the swirling dust particles together continuously while moistening the rubbish on the ground in a satisfactory manner.

The remaining components of the inventive sweeping machine 10 will now be described with reference to Figures 2 and 4.

As will be seen from Figure 2, the driven, rear brush device 29, which rotates in the direction of the arrow C, coaσts with a wear-resistant plate 33 which drags against the surface to be cleaned and extends trans- versely of said machine 10. The plate 33 has a trans¬ verse dimension which corresponds at least to the axial dimension of the brush device 29, and the upper part of which is connected to or merges with a cupped or re¬ cessed part 34, which in turn merges with an inclined part 35. The components 33, 34, 35 are suspended from the bottom of the machine body at a point 37, in the manner shown. The components 33-35 also assist in enclosing the aforesaid space.

The machine includes a rubbish elevator, generally referenced 38, comprising an endless belt 39 (Figure 4) which passes over an upper, driven roller 40 and a number of rotatable rollers 41, 42. The elevator 38 is driven in the direction indicated by the arrow D and the lowermost part of the elevator is located in the region of the cupped machine part 34, while its highest part dis¬ charges in the region of an emptiable waste-collecting container 43 located on the rear end of the machine. This arrangement provides a favourable distribution in weight, where the liquid tank 26 and the waste- collecting container 43 form a considerable machine loading mass.

The endless belt 39 of the elevator 38 may be made of hard rubber and includes mutually spaced openings 44

(Figure 4). Mounted between the belt openings 44 are a number of elongated dogging devices or shovel means 45 which project out at right angles to the belt 39. The width of the endless belt 39 corresponds typically to the axial length of the brush device 29. Mounted be¬ neath the rubbish elevator 38, in spaced relationship therewith, is a collecting plate 46 whose width typical¬ ly corresponds to the width of the belt 39 and whose upper end is folded over and forms a first guide means 47, while the bottom end of said plate is folded over to form a second guide means 48. Both guides are directed roughly vertically to the longitudinal axis of the machine. When the machine 10 is at work, the driven, rotating brush device 29 brushes all of the rubbish gathered by all brush devices onto the receiving plate

33. The rubbish is then pushed continually up along the receiver plate and into the cupped member 34 by incoming rubbish, into which the dogging devices 45 extend so as to pick-up and entrain the rubbish present in the cupped member, this rubbish being entrained to the highest point of the rubbish elevator 38 and falling gravita- tionally down into the rubbish collecting container 43. When large objects are transported upwards on the belt, for example branches and the like, such objects are able to fall through the openings 44 in the endless belt 39 and are therewith caught by the plate 46 and slide down along said plate back to the rubbish receiver plate 33. An endless belt 39 of the described construction is used so as to prevent large objects from deleteriously af- fecting the elevator drive and/or the brush drive.

Rubbish which is repeatedly captured by the plate 46 can be readily removed manually and placed in the container 43.

The illustrated, preferred embodiment of the improved sweeping machine is intended for attachment to the front of a tractor, a loading machine or some other suitable, automotive vehicle (not shown) and therefore pushed by said vehicle. To this end, the illustrated machine 10 has provided on the rear thereof a vertically moveable frame 49. Mounted on the top of the frame are hook devices 50 which coact with the loading device of the automotive vehicle (not shown) . Mounted on the frame 49 in the region of respective hook devices 50 is a pin 51 which slides in forked parts 52. Because of the earlier described load distribution of the machine elements, a larger part of the weight of the machine 10 can be transferred to the automotive vehicle, which is advanta¬ geous in the case of pushable sweeping machines.

Another advantage afforded by the inventive sweeping machine is that all driven components are activated by one or more individual hydraulic motors. For example, each of the three brush devices 22, 23, 29 is provided with at least one individual hydraulic motor. The drive shaft 40 of the rubbish elevator has at least one sepa¬ rate hydraulic motor and a hydraulic motor is provided for driving a pump functioning to pressurize the liquid in the tank 26. These hydraulic motors are not shown in detail and are commercially available. The advantage with this hydraulic motor arrangement is that the motors can be powered by the hydraulic system of the vehicle pushing the machine. This is effected with the aid of hydraulic hoses not shown. The sweeping machine 10 need not therefore be equipped with its own power source.

The preferred nozzle construction will now be described in detail with reference to Figure 5.

The pressurized liquid from the tank 26 enters the conventional nozzle 32 which includes a nozzle body 60 having a through-passing passageway and being provided with external screw threads. The liquid exits from the nozzle 61 in the form of a jet. The nozzle also in¬ cludes a sleeve 62 which on the surface thereof facing the direction of liquid movement (the arrow E) is pro- vided with a number of arms 63 which extend conically in towards the centre of the nozzle body 60 and there support a centrally positioned disc-like member 64, the centre of which is coincidental with the centre of the passageway in the nozzle body 60. The surface of the disc-like member 64 facing towards the nozzle body 60 may be completely smooth and flat, but may also be convex or concave. The sleeve 62 and the components 63, 64 form an inseparable unit which can be brought closer to or further away from the nozzle part 61 through the appropriate coaction between internal screw threads on the sleeve 62 and the external screw threads on the nozzle body 60. When liquid under high or rela¬ tively high pressure strikes the inwardly-facing surface of the member 64, the liquid jet will be disintegrated so as to form an extremely finely-divided liquid mist which is thrown out approximately perpendicular to the direction of the liquid jet and there spread over an area of 360°. The higher the pressure of the liquid, the more intensive and the more finer the liquid mist produced, and only a very short time is needed to achieve 100% air humidity within the aforesaid enclosed space, which is essentially only open at the bottom thereof towards the ground surface, and in and around the rotatable, driven brush devices 22, 23, 29. An important advantage in this respect is that only a relatively small amount of liquid, normally water, is consumed in comparison with the liquid quantities con¬ sumed by conventional sweeping machines. Consequently, a tank of smaller volumetric capacity can be used, thereby saving both space and costs.

Although the inventive machine has been described with reference to a preferred embodiment thereof, it will be understood by those skilled in this art that the inven¬ tive concept, i.e. the concept of substantially enclos- ing the space in which at least the rotatable, driven brush devices are located, together with the concept of generating a liquid mist within said enclosed space, can also be applied to existing sweeping machines of the kind to which the invention pertains. Automotive sweep- ing machines can also be constructed in accordance with the inventive concept.

The various functions of the sweeping machine 10 are preferably serviced from the vehicle used to push said machine.

Although the illustrated embodiment comprises two circu¬ lar brush devices and one elongated brush device, it will be obvious to the person skilled in this art that the inventive concept also includes other combinations of brush devices. For example, the machine may include two axially spaced brush devices and two brush devices which extend transversely to the longitudinal axis of the machine.

Claims

1. A machine for cleaning streets, pedestrian pre- cincts and other outdoor areas and also indoor areas, comprising a chassis which is carried by rotatable support wheels, at least two rotatable, driven ground- contacting brush devices, means for taking-up the rub¬ bish collected by the rotating brushes, and means for spraying the underlying ground surface with water in the region of the rotating brushes, c h a r a c ¬ t e r i z e d in that the area in which the rotating brushes are located within a substantially enclosed space which is open solely at the bottom thereof, and in that the liquid is delivered to said space in a mist form from at least one nozzle and in a manner such as to cause the liquid to spread approximately radially and preferably around 360^* upon exiting from the orifice of said at least one nozzle.

2. A machine according to Claim 1, c h a r a c ¬ t e r i z e d in that the liquid-spreading nozzle or nozzles is/are mounted above the brush devices.

3. A machine according to Claim 1, c h a r a c ¬ t e r i z e d in that there is attached to the machine a flexible and wear-resistant cowling element which extends downwards substantially into contact with the underlying ground surface and which embraces either completely or to a greater part the outer surface of the ground-contacting, rotatable brushes, such as to form a substantially enclosed space within which the rotating brushes work, said space being open essentially only at the bottom thereof.

4. A machine according to Claim 3, c h a r a c ¬ t e r i z e d in that the flexible cowling element can be flexed away from the machine to enable the rotatable brush devices to be inspected.

5. A machine according to one or more of Claims 1-4, c h a r a c t e r i z e d in that the machine is pro¬ vided with at least two nozzles for spreading liquid in mist form; and that each such nozzle coacts with an individual brush device.

6. A machine according to one or more of Claims 1-5, c h a r a c t e r i z e d by a distribution means allotted to each liquid-spreading nozzle, said distribu- tion means having the form of an adjustable, preferably disc-like device which is located axially in front of the nozzle and spaced at a distance therefrom, said device functioning to spread the liquid jet exiting from the nozzle orifice radially while simultaneously finely dividing the liquid to produce a mist.

7. A machine according to Claim 6, c h a r a c ¬ t e r i z e d in that the screw-threaded free-end of the nozzle is screw threaded and coacts with a sleeve or the like; in that rods are attached at one end thereof to the free surface of said sleeve; and in that the other ends of said rods are connected to the disc-like device.

8. A machine according to one or more of the preceding Claims, wherein said machine is equipped with three rotatable, driven brush devices, of which two brush devices are circular and rotatably mounted on the front of the machine, as seen in the forward direction there- of, about a vertical axis, and one brush device is an elongated device which extends transversely to the longitudinal axis of the machine and is driven for rotation about a horizontal axle, c h a r a c ¬ t e r i z e d in that the rearward, elongated brush device coacts with a rubbish elevator which functions to convey rubbish gathered by the brush devices to a rubbish-collecting container positioned downstream of said elongated brush device.

9. A machine according to one or more of the preceding Claims, c h a r a c t e r i z e d in that the means for collecting and carrying away rubbish includes an endless, inclined belt which has openings provided in mutually spaced relationship along its length and dog¬ ging devices which project radially outwards from the belt.

10. A machine according to Claim 9, c h a r a c ¬ t e r i z e d by a guide plate which is mounted beneath the elevator and extends parallel therewith and one end of which is located in the vicinity of the rubbish- collecting container and the other of which, the lower end, discharges in front of the elongated brush device, as seen in the forward movement direction of the machine.

11. A machine according to one or more of Claims 8-10, c h a r a c t e r i z e d by a cupped member which extends transversely to the direction of machine move¬ ment in the region of the bottom part of the rubbish elevator, and which coacts with the brush devices, particularly the elongated brush device through the intermediary of a flexible plate inclined to the surface of the ground.

12. A machine according to one or more of Claims 8-11, c h a r a c t e r i z e d in that the width of the elongated brush device and the width of the elevator belt are typically equal to one another.

13. A machine according to one or more of the preceding Claims, c h a r a c t e r i z e d in that each brush device is provided with means which enables the ground- contacting pressure of said brush devices to be adjusted.

14. A machine according to one or more of the preceding Claims, c h a r a c t e r i z e d in that each brush device is driven by at least one separate hydraulic motor; in that the rubbish elevator is assigned at least one individual hydraulic motor; in that a separate hydraulic motor is provided for driving a liquid pump; and in that all hydraulic motors are powered by the hydraulic system of the vehicle towing or pushing said sweeping machine.

15. A machine according to one or more of the preceding Claims, c h a r a c t e r i z e d in that the machine is provided at one end thereof with means for detachably connecting the machine to an automotive towing or push¬ ing vehicle.