Motorised device for cleaning large surfaces

Abstract: The device comprises at least a central brush (2) having an horizontal axis (1) rotatable at a preset speed, the rotary shaft of said brush (2) is mounted on at least one floating arm (4,5) or lever and is provided with means to control the working position of the brush (2) and the width and frequency of its oscillations during the operation of the device.

Description: The present invention relates to a motorised device for cleaning large surfaces, also known as motor-broom, and in particular a self-propelled vehicle provided with two or more side brushes having almost vertical axes and with at least one cylindrical brush having an horizontal axis mounted in the back of the vehicle in a central position to collect wastes pushed towards it by the side brushes and project them towards the inside of the vehicle where they are sucked and deposited into an appropriate collecting box. The vehicles of this are motorized by an internal-combustion engine or an electric motor, according to the type of use foreseen. Said motor can provide power both for moving the vehicle and for moving the brushes, or alternatively a suitable electric motor can be envisaged for actuating the brushes. These vehicles are designed for cleaning large asphalted or in any way paved surfaces, which very often present considerable accidents and bumps, typically holes, depressions and small bulges, which cause two kinds of inconveniences. In fact, on one side, in correspondence with said bumps the regular contact between the horizontal brush and the surface to be cleaned is interrupted and therefore cleaning is no longer effective. On the other side, the brush and related mechanical members are submitted to abrupt stresses, even of high intensity, which negatively affect the useful life as well as the maintenance cycles of said machines. DE-A-2 455 200 shows a cleaning device of the type referred to comprising a central brush with a horizontal rotary shaft mounted on a floating aim, whose movements are controlled by an hydraulic cylinder and circuit. GB-A-2 126 633 relates to a road sweeping apparatus with a brush having an horizontal axis mounted on a swingable double lever controlled by rams. EP-A-0 134 409 discloses a sweeper having a linkage and spring system to maintain substantially constant the pressure exherted on the road by the sweper notwithstanding its wear. Stating what precedes, an object of the present invention is to overcome different inconveniences and limitations of the prior technique and in particular to provide a motorised device for cleaning large surfaces wherein the horizontal brush is movable in vertical direction and allows an almost automatic compensation of the ground bumps, said feature being obtained in a particularly simple and economical manner, with one linkage only further connecting the brush with a control lever of the positions thereof. A further object of the invention is to provide a motor-broom provided with means to compensate in an easy and quick way the wear of the central brush. The system should to be simple, in that obtained by using mechanical pieces (arms and levers), and nevertheless very effective. These objects are achieved by means of the invention, as reported in the characterising portion of claim 1. The invention will be now described more in detail with reference to preferred embodiments, illustrated in the accompanying drawings, wherein: Figure 1 is a schematic and partial view from the top of the floating arrangement of the brush according to the invention: Figure 2 shows a preferential configuration of a floating lever; Figure 3 is a schematic view of the control linkage of the vehicle according to the invention; and Figure 4 is a schematic view illustrating the device for compensating the brush wear. With reference first of all to Figure 1, the device according to the invention comprises a brush 2, substantially cylindrical and with horizontal axis, rotatably mounted between two floating arms or levers 4, 5. The arms 4, 5 are pivoted in a known way to the body of the machine and are rigidly connected to each other by means of a pivot 3. The brush 2 is mounted, rotatable about its own axis 1, at the free ends of said floating arms in such a way to be able to move in a vertical direction in order to adapt its position to the depressions and bulges of the surface to be cleaned. In case the brush 2 is actuated by a combustion motor, the movement is transmitted to it in a known way through driving gears as will be evident to those skilled in the art and the floating arms, or levers, do not require particular configurations. Figure 1 shows an embodiment wherein the brush actuating motor is an electric motor. In this case, as better shown in figure 2, at least one of the levers (lever 5 in fig. 1) is L-shaped and comprises an arm on which said electric motor M is mounted. The transmission of the movement to the brush is thus simplified, the shaft of the motor M bears a pulley PM around which a driving belt 8 is wound and, through a pulley PS integral to the brush axis, directly transfers the movement of rotation to the brush 2, which movement results in the same direction as that of the vehicle on the surface to be cleaned. As it can be noticed, the floating arms 4 and 5 are placed in front of the brush 2 considering the direction of movement and this fact, together with the direction of rotation of the brush, might lead to a crawling of same. In order to ensure optimal conditions of operation, at least one of the arms is provided with means to control the working position of the brush as well as the width and frequency of the oscillations of said arm during the operation of the device. As schematically shown in figure 3, said means to control the working position of the brush comprise a rigid linkage (26, 27, 33, 34, 35) which connects the floating arm 5 with an operating lever 37 which is operable by the operator; an adjusting screw 42, 43, or similar means engageable by the lever 37 to limit its downward run; and a spring or similar elastic means which engages said linkage to push the floating arm 5 and therefore the brush 2 towards the ground. The means to control the width and frequency of the oscillations of brush 2 comprise a damper in engagement with the rigid linkage to control the width and, frequency of the oscillations when the brush 2 (and the arm 5) is pushed upwards. The control of the width of the oscillations, or better of the translations that take place when the brush is stressed upwards, is ensured by a pivot-slot connection between two elements of said linkage, preferably between the two elements immediately upstream the arm 5. In the preferred embodiment as shown in figure 3, the funtion of spring and damper is performed by a single element, consisting of a pneumatic spring 49 which acts on a three-armed lever 34 present in said rigid linkage. Analysing the linkage more in detail, the sequence of its elements is as follows: the brush 2 is rotatably mounted in 1 on an end of the horizontal portion of the arm 5, the other end of which is pivoted or articulated in 25 to the frame of the vehicle. The arm 5 is pivoted in 25A to an end of a rod or rigid tie rod 26, the other end of which is fastened by means of said pivot-slot connection to a vertical lever 27, floating with respect to the frame of the vehicle thanks to a pivot 28 present on the lower end of said lever. As it can be noticed, the slot 30 is provided in one head 29 integral to the rigid tie rod 26, and is slidingly engaged with a pivot 31 integral to the floating lever 27 in the vicinity of its upper end. The length of the slot is approximately of 20-30 mm. Moreover the floating lever 27 is articulated in 32 to a second driving rod 33, hinged to a first arm of a three-armed lever 34 pivoted in 44 to the frame of the vehicle. The second arm of the lever 34 is hinged to a control rod 35 which is pivoted in 36 to the lower end of the operating lever 37 having an L-configuration and comprising an upper section 39 ending with a knob 41 to be actuated by the operator, and a shorter lower section 38. The operating lever 37 is furthermore pivoted in 40 to the frame of the vehicle and its upper end is movable in an elbow guide 37A between an operative position when the brush is lowered and a rest position with lifted brush. Under the operating lever 37 an adjusting screw 42 is provided, which is screwed in a seat or nut screw 43 integral with the frame, in a way to limit the maximum downward displacement of the lower section of the operating lever 37. The third arm integral to the lever 34, as indicated by reference 45, is connected through a movable stem 50 to said pneumatic spring or gas spring 49 which is pivoted at its other end, in 51, to the frame of the vehicle. Preferably, as shown in Fig. 3, the articulation of lever 34 is of the so-called shackle type, with the lever 47 rigidly fastened in 46 to the arm 45 of the lever 34 by means of a screw and with its free end pivoted in 48 to the stem of the gas spring 49. By loosening the screw 46 and rotating the section 47, it is possible to change the length of the lever arm, and therefore to vary the load of the gas spring 49. As previously mentioned, the gas spring 49 performs a double function in that it acts as a damper and moreover applies a load to the brush in such a way to provide the necessary strength to avoid the brush jumping. The use of separate damper and spring is thus avoided. When the vehicle is transferred and in general when a cleaning action is not required, the brush 20 is kept raised from the ground S, and this is obtained by the operator engaging the operating lever 37 in the non operative position of the elbow guide. To lower the brush to its working position as shown in Fig. 3, the operating lever 37 is released and brought to said working position of the guide 37A and the linkage, which constitutes a rigid mechanically connected group, lowers. When the brush reaches the ground, it stops, but however the gas spring 49 continues to exert a thrust F directed according to its own axis, which determines a couple with respect to the fulcrum 44 of the rigid lever system represented by the linkage group. As a result of this action, the floating lever 27 rotates around the fulcrum 28 driving in the movement the pivot 31 which moves inside the slot as far as to reach the position A shown in Fig. 3. By means of the pivot 31 which is now in its end stroke position, the thrust supplied by the gas spring 49 is now applied to the brush 2. In order to adjust the working position of the brush, the adjusting screw 42 is screwed and the lever 37 is released allowing the gas spring 49 to push the brush 20 against the ground, then the adjusting screw 42 is moved again until its end is in contact with the portion 38 of the lever 37. During operation, when the brush finds a bulge and the arm 5 is stressed upwards, the pivot 31 acts on the linkage loading the gas spring 49; on the contrary, in case of downward movement of the brush, caused by a hole, the linkage cannot move backwards, however the downward movement is made possible by the idle run of the pivot 31 within the slot 30 up to position B. According to a further aspect of the invention, the motorised device is provided with means to adjust in horizontal direction the position of the brush to compensate its wear during its useful life, keeping it at the proper distance from the front wall of the brush box. As illustrated in fig. 4, the free end of the floating lever is preferably mounted on an arm 11, turnable around the fulcrum 10 to position at least in horizontal direction the brush 2 with respect to the frame of the vehicle. The position of the free end 25 of the arm 11, where the floating lever 5 is pivoted, can be controlled in any known way, for instance by means of a cam. However, in the preferred embodiment as shown, said position is controlled by an arm 11 pivoted in 10 and kept in position by a locking System 12. By loosening the locking system 12, the lever 11 pivoted in 10 moves according to a circumference arc displacing the end 25 ahead and downwards, carrying the worn brush to gently rest on the front wall of the brush box and simultaneously on the ground, as indicated by dashed lines in figure 4. The movement of lever 11 is caused by the weight of the elements hanging thereto (namely the brush 2 and the arm 5) and can be possibly helped by an elastic member (not shown).

Claims: A motorised movable device for cleaning large surfaces, comprising at least a central cylindrical brush (2) having a vertically movable horizontal shaft (1), rotatable at a preset speed, said shaft (1) being mounted on at least one floating arm (5), said arm or arms being provided with means to control the vertical position of said brush and to control the width and frequency of the vertical oscillations of said brush during the device operation, in the form of a rigid linkage (26, 27, 33, 34, 35) which connects at least one floating arm (5) with an operating lever (37) to be actuated by an operator; a pneumatic spring (49) being engaged with said linkage to stress said floating arm towards the ground and to dampen the width and frequency of the arm oscillations when the brush (2) is stressed upwards, characterised in that said pneumatic spring (49) engages a three-armed lever (34) included in said linkage, said lever (34) being further connected upstream with a control rod (35) fastened to said operating lever (37) and downstream with a second driving rod (33), connected with one of said floating arms (5). A device according to claim 1, characterized in that the arm of said three-armed lever (34) connected with said pneumatic spring (49) comprises two arm portions (45, 47), one (45) of which is fixed to said three-armed lever (34) and the other (47) is pivoted to said pneumatic spring (49), said arm portions being releasably connected (46). A device according to claim 1 or 2, characterised in that said second driving rod (33) is connected with said arm (5) through a floating lever (27) and a rigid tie rod (26), and in that a pivot-slot connection (30, 31) is positioned between said floating lever (27) and said rigid tie rod (26), the pivot (31) of said connection being integral to said lever (27) and the slot (30) being provided in a head (29) integral to said rigid tie rod (26). A device according to one of the preceding claims, characterised in that said floating lever or levers (5) of the brush (2) are mounted on the free end of at least one arm (11), rotatable in a controlled way within a preset angle to adjust at least in the horizontal direction the position of the brush (2) and therefore compensate its wear. A device according to claim 4, characterised in that the end (25) of said rotatable arm (11), on which said floating lever(5) of the brush (2) is mounted, is movable according to a circumference arc directed towards the ground and towards the front portion of the device, in order to simultaneously adjust the brush position with respect to the ground and to the wall of the brush box. A device according to claims 4 or 5, characterised in that the movement of said rotatable arm is caused by an elastic element and/or by the load of group of elements hanging on said arm. A device according to one of the preceding claims, wherein said brush (2) is actuated by an electric motor (M), characterised in that said floating lever or levers (5) are L-shaped and in that said driving motor of the brush is mounted on the vertical arm of said L-shaped lever.

Inventors: SONZOGNI FRANCO, SONZOGNI, FRANCO
Applicants: PULIMAT SPA, PULIMAT S.P.A.
Application year: 1991
Main classification: E01H1
IPC codes: E01H1