FR2460600A1 - DEVICE FOR LAWN MOWER - Google Patents

Abstract

MOWER FEATURING, ON THE BLADE ROTOR, FAN BLADES THAT STRENGTHEN THE AIRFLOW EJECTING THE CUT GRASS. THE MOWER HAS A HOOD MOUNTED ON WHEELS 5 AND CARRYING A MOTOR SHAFT 6 TO WHICH IS FIXED A ROTOR DISC 7 EQUIPPED WITH BLADES 8. ON THE SAME DISC, FAN BLADES 12 ARE PLACED WHICH, THANKS TO BAFFLE 15, STRENGTHEN AIR FLOW PUSHING CUT GRASS INTO THE EJECTION CHANNEL 9.

Description

The present invention relates to a device for a lawn mower which

  is provided with a cut grass ejection means and is of the type having a cutting rotor driven by a motor, provided with oblique knives and placed under a wheel-supported hood and protecting the rotor on the top and laterally, said ejection means comprising a passage which starts from the inside of the hood and whose outer end can be connected to a

cut grass collector.

  It is already known to use the movement of the air generated by inclined knives to effect the ejection of grass cut by lawnmowers of this type, the air being sucked on the lower edge of the hood of the mower and being blown through

  the ejection opening at the same time as the cut grass.

  In order to increase the flow of air, a disc carrying the

  knives were fitted with fan blades which, in the area

  above the plane of opening of the blades, cause the deflection of the jet of air, directed upwards by the knives, in a peripheral direction towards a substantially tangentially directed exit. It has been found, however, that the amount of air that can be drawn along the bottom edge of the mower hood is insufficient to produce a strong air movement for the mower deck.

transport of grass waste.

  To remedy this, separate food openings

  Air distribution has been provided, for example in connection with the ejection opening or centrally around the vertical shaft of the cutting rotor. However, such separate air supply openings have not yielded the desired results either, but it often happens, especially when the grass is dense and wet, that the possibility of entrainment of the air jet becomes insufficient. and that the cut turf already stops in the ejection opening, which obstructs it. When the ejection opening is blocked, the fan blades, to which air is sucked from the separate air opening, produce inside

  of the hood a movement of air which counteracts the effect which, under the conditions

  is produced by the oblique knives and which raises the turf and drives it upwards, since the air sucked by the fan out through the space between the edge

  bottom of the hood and the floor, if the passage is large enough.

  The efficiency of the fan also decreases considerably, because a free-running centrifugal fan can not work effectively against the high resistance caused.

  by the pressure established inside the hood.

  Clogging of the mower opening and mouth near the cut grass catcher

  prevent collection and also have a very poor

  on the cutting function, since the grass along the edges

  the hood is pushed down instead of being lifted.

  The object of the invention is to provide a device for obtaining effective ejection of cut grass in

  ensuring a flow of violent air exiting through the ejection passage

  tion. The new device is characterized in that it is provided with means for producing a flow of air acting in the ejection passage and accelerating the air passing through the passage as well as the cut grass carried by the air, and said means comprises a centrifugal fan driven by a motor, acting in a helical space separated from the cutting zone, said fan being designed to draw air from the zone outside the mower deck; and to blow the air with an ejection effect towards and through the ejection passage

hood grass.

  Other features and advantages of the invention

  will be better understood by reading the following description

  of an exemplary embodiment and with reference to the accompanying drawings, in which: - Figure 1 shows a lawn mower seen from below; Figure 2 shows a section along the line A-A of Figure 1; and - Figure 3 shows a section along the line

B-B of Figure 1.

  The lawnmower comprises a generally circular hood 1 which is provided at the front and at the rear with extensions 2 and 3 on which are mounted wheels 4 and 5 which are preferably adjustable. At the top of the hood is a motor (not shown) which may be an internal combustion engine or an electric motor. To the vertical motor shaft 6, a circular rotating disc 7 to which are connected inclined knives 8 is connected. Instead of the rotary knives shown which pivot on the disc 7, it is obviously possible to have a rigid knife arm. mounted

under the disk.

  In the hood, there is an ejection channel 9 to open.

  tangential ture, to which can be connected a basket not shown

for cut grass.

  The passage or ejection channel 9 extends helically upwardly and outwardly of the circular hood 1, and has a bottom 10 which extends at a distance in the

peripheral portion ll of the hood.

  According to the invention, there is provided a means for providing an ejection effect which acts in the ejection passage and which is directed towards the outside of the hood. In the embodiment shown, this means is a centrifugal fan. The fan includes a

  wheel and hood having a central inlet and a tangential outlet.

  The fan wheel is provided with the rotating disc 7 and blades 12 placed on the top thereof. The hood of the fan is delimited axially upwards by the central portion of the hood 1 which is provided with one or more suction openings 13 adjacent to the shaft 6. It should be noted in this regard that the motor, to allow suction free, is slightly raised from the top of the hood 1 by means of spacer blocks 14. The fan cover is delimited downwards by the rotating disk 7 and radially by a helical baffle 15 which is attached to the underside of the hood i d where he goes down. The cabinet 15 is sized relative to the disk 7 so that the disk closely follows the major

  part of the length of the cabinet with the necessary play.

  The blow aperture formed at the outer end 16 of the baffle is placed and oriented so that the flow of air from the fan passes into the ejection channel 9 and produces, as a result of the ejection effect thus generated. , a violent suction effect

  which accelerates and evacuates the air and the cut grass it carries.

  During operation, the air is sucked in a known manner under the hood by means of the inclined knives 8, the air movement directed upward straightening the grass, so that it is more easily cut by knives. As a result of the fan ejection function, there has been found, at least in the area at the inner end of the ejection duct, an air depression such that the cut grass located in the area above the exhaust duct. knife path and air carrying this grass are sucked towards this inner end. The air that is sucked to the lower edge of the hood by means of the inclined knives is deflected by the movement of the knives in the direction of the rotation of the rotor, and it rises towards the inside of the ejection channel as a result of the effect of the knives. When the air carrying grass in the vicinity of this entrance is pushed by the air of the fan> it occurs

  an acceleration that gives a long and prolonged ejection effect.

  The grass introduced into the basket collects this basket, and the accumulation of grass that pockets the ejection

  is eliminated at the entrance of the ejection channel.

  A portion of the bottom 10 of the ejection channel 9 is mounted

  hinged, like a hatch 17, at the inlet end of the channel.

  The hatch 17 has been made on the one hand, for security reasons and, on the other hand, to allow control of the amount of grass ejected. In some cases, it is desirable - so as not to deplete the grass - to leave at least some of the cut grass on the grass. The hatch 17 is pushed by an elastic means, so that it tends to take an upwardly inclined position, in which it closes the ejection passage. The trapdoor is coupled to a blocking device for the cut grass collector, so that it is kept open only when the collector is connected. This is achieved for example by connecting to the hatch 17, the

  means of a wire or bar, a stirrup carrying a means of

  which can be passed over the mouth of the ejection channel. The adjustment of the hatch in the partially open position can be carried out by means of a device displacing the

  bar or wire towards the closed position.

  To reduce the upward inclination of the cut grass ejection channel 9, the lawn mower is provided at the rear, according to the invention, with two pairs of small wheels 5 supported by an articulated rocker bogie. 18. The bogie allows the

  outer portion of the canal to be in a practically horizontal position

  tal. The truck 18 pivots in a limited way because of the stops 19 which are fixed on the extension 3 of the hood. The limited pivoting provides an additional maneuverability to the mower, which occurs by lowering the handle, so that the front wheels 4 are lifted off the ground. If the handle is lowered a short distance, the mower pivots about the axis 20 of the bogie, so that the front end of the mower is raised a few degrees from the ground. However, if the handle is lowered further, the truck encounters the stops 19, so that the mower rotates about the axis of the rear wheels and we obtain a faster and more important lifting of the front part

of the mower.

  The grass basket has an upper part which can be applied, on the one hand, against the mouth of the grass ejection channel and, on the other hand, against the handle of the mower and against

  a recovery container from said upper part.

  This can be provided with appropriate outlet openings for the air used. The recovery container is made in one

  soft material, foldable, and it is preferably permeable to air.

  The device of the invention can be used both in lawnmowers which are pushed by hand as in self-propelled mowers. The device is also applicable to riding mowers who have one or

several cutting sets.

  Of course, various modifications can be made by those skilled in the art to the devices or processes which have just been described as non-limiting examples.

  without departing from the scope of the invention.

Claims (6)

R E V E N D I C A T IO N S   1. A device for a lawnmower which is provided with a means for ejecting cut grass and which is of the type comprising a cutting rotor driven by a motor, provided with oblique knives and placed under a hood supported by and rotor-protecting wheels on the top and laterally, said ejection means comprising a passage which extends from the inside of the hood and whose outer end can be connected to a cut grass catcher, characterized in that is provided with means for producing a flow of air acting in the ejection passage and accelerating the air passing through the passage as well as the cut grass carried by the air, and in that said means comprise a centrifugal fan driven by a motor, acting in a helical space separated from the cutting zone, said fan being adapted to draw air from the zone outside the mower deck and to blow the air with a cooling effect; ejection in direction e t at   through the grass ejection passage of the hood.   2. Device according to claim 1, characterized in that the fan is a centrifugal fan having blades arranged on a disk which is fixed above the knives and connected to the motor shaft, the fan having a boundary wall in form   propeller, placed substantially axially, which delimits radial-   in the space under the hood, the working space of the fan wheel consisting of the disk and the blades, and in that the working space is delimited upwards by the top of the hood which , in the vicinity of the motor shaft, is provided with a suction opening of appropriate shape, the space being delimited   downwards by the rotating disk that supports the blades of ventilation.   and has a diameter substantially adapted to the extension   radial maximum of the helical boundary wall.   3. Device according to claim 2, characterized in that the end of the helical boundary wall delimiting the fan outlet is located in the vicinity of the end.   entrance of the ejection passage of the cut grass.   4. Device according to claim 1, characterized in that the inlet end of the grass ejection passage is determined downwards by a movable portion, similar to a hatch, which, in the closed position, is aligned with the intended direction of ejection of the grass along the passage and, in closed position, closes said passage, and in that the hatch-like portion is urged by a spring and coupled to a connecting means for   the grass collector, so that the passage can be complete.   open when the grass catcher is plugged in.   5. Device according to claim 4, characterized in that the hatch-like portion is adjustable in intermediate positions to allow the ejection of a certain amount of cut grass and drop the remaining grass on floor.   6. Device according to claim 1, characterized in   what the hood of the lawn mower, in order to decrease the incline   upward of the grass ejection passage, is provided at its rear end with two pairs of wheels arranged on each side of a tilting bogie which is movable at an angle of rotation limit.