Improved motor sweeper

Abstract: A motor sweeper comprising a frame (10) below which there are provided at least one rotatable front lateral conical brush (1) able to swing about a vertical axis, a steerable wheel (2) to the rear thereof connected to steering control means, a rearward-lying transverse horizontal cylindrical brush, two drive wheels to the rear thereof, and a rear dirt collection bin, said at least one conical brush being maintained in its working position by an elastic means (120), in which between the machine steering unit and the support structure for said at least one conical brush (1) there is interposed a member (62) which is normally insensitive to the operating position of the steering control means, but which, when the machine confronts a curve involving a steering angle exceeding a predetermined value, causes that lateral brush situated on the outside of the curve to swing inwards.

Description: This invention relates to improvements in motor sweepers used for cleaning indoor and outdoor surfaces and floors in general. For such purposes, motor sweepers have been widely used for some time, they comprising essentially a frame with a driver compartment below which there are provided at least one front lateral conical brush, a steerable wheel to the rear thereof, a rearward-lying transverse horizontal cylindrical brush, two drive wheels to the rear thereof, and a rear collection bin for the dirt collected by the cylindrical brush. Modern motor sweepers comprise two opposing front conical brushes which are adjustable in height, and are each provided with an electric drive motor which rotates them in such a manner as to convey the dirt towards the longitudinal axis of the machine, and hence towards the cylindrical brush. In particular, each conical brush is located at the end of a horizontal arm branching from a vertical shaft which is axially slidable for adjusting the height of the brush, and is connected to the frame by an elastic positioning member, such as a spring. The purpose of said elastic member is to prevent the respective lateral brush, and the elements associated with it, from undergoing damage on sudden collision with fixed structures, such as a pavement. In particular, during a usual sweeping operation, said elastic member maintains the lateral brush swung outwards, where it rests against a limit stop and where, typically with reference to straight-line advancement of the machine, it becomes partly superposed on the corresponding end of the rearward-lying cylindrical brush, and extends beyond it. Moreover, when the lateral brush collides against an obstacle, it retracts against the force of the elastic member, to then automatically return into position when said obstacle has been overcome. The as yet unsolved problem of such motor sweepers is the incomplete sweeping of that surface strip covered by the machine when confronting relatively narrow curves. In such situations, the cleaning face of the machine, defined by the lower portions of the cylindrical brush and of the lateral brushes in contact with the surface to be swept, is in fact noncontinuous in contast to the case when the machine travels in a straight line or confronts curves which are not particularly narrow, in which each lateral brush is partly superposed on the corresponding end of the cylindrical brush. In particular, beyond a certain steering angle or, in other words, below a certain radius of curvature, the inner rear peripheral region of that lateral brush which at that moment lies external to the curve undergoes a trajectory which is non longer superposed on the trajectory of the corresponding end of the cylindrical brush, but is spaced from the point of contact with the ground at said end by a distance which increases as the steering angle increases. Essentially, it happens that along the cleaning strip covered by the machine on undergoing fairly narrow curves, there remains an uncleaned band of surface. To complete the cleaning, the operator is therefore compelled to again sweep this region, but this time following a different path than previously. Said problem, which results in loss of time and extra consumption of energy and materials, is particularly serious if particularly tortuous paths are involved such as in workshops and stores where machinery and materials are parked. The main object of the present invention is to obviate the aforesaid within the context of a simple, rational and reliable construction. Said object is attained by virtue of the characteristics indicated in the claims. According to the invention, said object is attained, within the context of a motor sweeper as defined in the introduction, by interposing between the machine steering unit and the support structure for said at least one lateral brush, a member which is normally insensitive to the operating positions of the lateral brush and of the steering unit, but which, when the machine confronts a curve involving a steering angle exceeding a predetermined value, causes that lateral brush situated on the outside of the curve to swing inwards. Preferably said inward swing takes place against the force of the elastic means for repositioning the brush, or in other words, rearwards with reference to the travelling direction, with consequent approach of the lateral brush to the facing end of the rearward-lying cylindrical brush. Said predetermined value corresponds to that steering angle at which the inner point of contact between the ground and that lateral brush situated on the outside of the curve is no longer superposed in the direction of the travel trajectory on the point of contact between the ground and the facing end of the cylindrical brush, but is spaced from it towards the outside of the curve. Said member preferably consists of a connecting rod which at one end is pivoted to the ring gear controlling the direction of the steerable wheel, and at the other end presents a slot with which a pin associated with said support structure for the lateral brush is slidingly coupled. Preferably said pin is carried by a lever branching from the vertical shaft which supports the lateral brush, and with which said lever is torsionally but not axially engaged. All the objects of the invention are attained by the aforedefined solution. In this respect, by virtue of said inward and preferably rearward swing of the lateral brush, the strip covered by the cleaning front of the machine is completely swept, without leaving the inconvenient dirty band described in the introduction. The constructional and operational characteristics and merits of the invention will be more apparent from the ensuing description thereof given with reference to the figures of the accompanying drawings which illustrate a particular preferred embodiment thereof by way of non-limiting example. Figure 1 is a transparent partial plan view from above showing the front right part of a mechanical sweeper according to the invention in its straight-line travel configuration. Figure 2 is a view in the direction II of Figure 1. Figure 3 is a view on a smaller scale totally similar to that of Figure 1, showing the machine again in straight-line travel but at the moment in which the right lateral conical brush collides against an obstacle. Figure 4 is a view similar to the preceding, showing the machine at the moment in which it confronts a curve towards the right with maximum steering angle. Figure 5 is a view totally similar to that of Figure 1, showing the machine at the moment in which it confronts a curve towards the left with a steering angle close to the value at which the means of the invention intervene. Figure 6 is a view similar to the preceding, showing the machine completely steered towards the left, with intervention of the means of the invention. Firstly it should be noted that the machine shown is provided with two front lateral conical brushes, of which only the right brush is shown for reasons of simplicity and clarity. The description of said right brush is specularly valid also for the left brush, the teachings of the invention also having the same value for motor sweepers with only one conical brush 1. Said figures show a frame 10 below which there are positioned said two conical brushes 1, a rearward-lying steerable central wheel, and the other elements stated in the introduction, but which do not require description as they do not involve any characterising part of the invention. The wheel 2 is rotatably mounted on a fork 3 connected to the frame via the thrust bearing 4. Below the thrust bearing 4 there is a usual ring gear 5 which is rotated in the two opposing directions in the usual manner by the machine steering unit (not shown). Said ring gear 5 is provided with two salient peripheral pins 6, described hereinafter, which with the machine in straight-line travel configuration (see Figures 1 and 3) are symmetrically disposed about the longitudinal axis thereof. To the right of the central longitudinal member of the frame 2 (see Figures 1, 3, 4, 5 and 6) there is a support 9 within which there is mounted a bush 99 (see Figure 2) which receives a slidable vertical cylindrical shaft presenting at its upper end usual height adjustment means (not shown). Below said support 9 and bush 99 there is provided, stationary in height, a sleeve 11 which is torsionally, but not axially, engaged with said shaft 8. To the lower end of the shaft 8 there is projectingly fixed a box arm 14, the free end of which supports an electric motor 140 for rotating the brush in the direction of rotation indicated by A in the figure, via the perpendicular transmission indicated by 15. At the top and at the base of said sleeve 11 there are two levers 12 and 13 respectively, forming overall a lever of rocker type. The first lever 12 is connected to the frame 10 via a tension spring 120, and is provided with an abutment 121 arranged to rest against an adjustable threaded end-of-swing push rod 122. The second lever presents a salient pin 60 received, as a precise free-sliding fit, within a terminal longitudinal slot 61 in a connecting rod 62, which at its opposite end is pivoted on the right pin 6 of the steering ring gear 5. In particular, as further described hereinafter, said slot 61 has a length such that the position of the connecting rod normally does not modify in any manner the operating configuration of that part of the machine illustrated, the connecting rod 62 remaining inactive until the value of the steering angle of the wheel 2 exceeds the predetermined value defined in the introduction, beyond which it retracts inwards and rearwards that brush 1 which at that moment is situated on the outside of the curve. This means that it retracts the right brush 1 under leftward steering and the left brush when the machine steers towards the right. The aforesaid is well represented in the figures. In particular, and with reference only to the illustrated right brush 1, when the machine travels in a straight line (Figure 1), or confronts leftward curves having a steering angle of value less than the predetermined value (Figure 5), or follows rightward curves of any radius (Figure 4), the pin 60 does not make contact with either the one or the other end of the slot 61, even when the brush i encounters an obstacle 88 as indicated in Figure 3, in which case it automatically retracts by overcoming the return action of the spring 120. At the moment in which said predetermined value of the steering angle is exceeded (towards the left in the present case), the pin 60 rests against the outer end of the slot 61, and the connecting rod pulls the brush 1 inwards (see Figure 6), it returning into its normal operating position when the steering angle returns below said predetermined value. The merits and advantages of the invention are clearly apparent from the aforegoing and from an examination of the accompanying figures. The invention is not limited to that illustrated and described, but includes all technical equivalents of the invention and their combinations, if implemented within the context of the following claims.

Claims: A motor sweeper comprising a frame (10) below which there are provided at least one rotatable front lateral conical brush (1) able to swing about a vertical axis, a steerable wheel (2) to the rear thereof connected to steering control means, a rearward-lying transverse horizontal cylindrical brush, two drive wheels to the rear thereof, and a rear dirt collection bin, said at least one conical brush being maintained in its working position by an elastic means (120), characterised in that between the machine steering unit and the support structure for said at least one conical brush (1) there is interposed a member (62) which is normally insensitive to the operating position of the steering control means, but which, when the machine confronts a curve involving a steering angle exceeding a predetermined value, causes that lateral brush situated on the outside of the curve to swing inwards. A motor sweeper as claimed in claim 1, characterised in that said swing takes place towards the rear with reference to the direction of travel. A motor sweeper as claimed in claim 1, characterised in that said member consists of a connecting rod which at one end is pivoted to the steering control means, and at the other end presents a slot with which a pin positioned on a horizontal arm associated with the lateral brush support structure is coupled by an engagement allowing bilateral idle movement, A motor sweeper as claimed in claim 1, characterised in that said cylindrical control means comprise a ring gear coaxial with and rigid with the shaft about which the steerable wheel rotates. A motor sweeper as claimed in claim 3, characterised in that one end of said connecting rod is pivoted on a pin projecting from said ring gear. A motor sweeper as claimed in claim 3, characterised in that at its other end the connecting rod is pivoted on a pin carried by a lever branching from the shaft about which the lateral brush swings. A motor sweeper as claimed in claim 6, characterised in that said vertical shaft is the usual shaft for adjusting the height of the lateral brush.

Inventors: MONTIPO FULVIO, MONTIPO, FULVIO, MONTIPO, FULVIO, INTERPUMP ENGINEERING S.R.L.
Applicants: INTERPUMP ENGINEERING S R L, INTERPUMP ENGINEERING S.R.L.
Application year: 2001
Main classification: A47L11
IPC codes: A47L11, E01H1