GB2376165A

GB2376165A - Hand guided rotavator

Info

Publication number: GB2376165A
Application number: GB0210130A
Authority: GB
Inventors: Mario Possamai
Original assignee: ALPINA SpA
Current assignee: ALPINA SpA
Priority date: 2001-05-08
Filing date: 2002-05-02
Publication date: 2002-12-11
Also published as: FR2824444B3; FR2824444A3; GB0210130D0; ES1051928U; ITVE20010011U1; DE20206948U1; ES1051928Y

Abstract

A rotavator comprises a handle 2 and a motor connected to impart rotation to an annular member 18 whose axis is generally vertical and from which depends a cutter having a U-shaped blade (32, figure 2). The cutter 32 is mounted for rotation about a generally vertical axis and the annular member 18 includes a peripheral gear 16 which cooperates with at least one further gear (26, figure 3) provided about the periphery of a second annular member (28, figure 3) from which also depends a cutter having a U-shaped blade. The arrangement is such that the rotational path of the first blade (32) intersects that of the second blade.

Description

2376 1 65

ROTAVATORS

This invention relates to rotavators for breaking up and tilling soil.

Rotavators are known which comprise a rod-shaped handle secured to a housing for an internal combustion engine or electric motor whose drive shaft is coupled to a generally horizontal shaft which carries at each of its ends a bladed cutter.

Such rotavators have the disadvantage that they frequently cause discomfort to the user during the earth tilling process because of considerable shaking caused by the impact of the blades with lumps of earth.

Such rotavators also suffer from the disadvantage of poor earth disintegration performance because of the dead regions existing between the two bladed cutters.

An object of the invention is to eliminate, or at least alleviate, these disadvantages by providing a rotavator of enhanced reliability which, in use, either eliminates or substantially reduces the shaking referred to above.

Another object of the invention is to provide a rotavator which is compact and enables optimum penetration below tobacco, maize and general vegetable leaves.

In one aspect, the invention provides a rotavator comprising a handle and a motor connected to impart rotation to an annular member whose axis is generally vertical and from which depends a cutter having a U-shaped blade mounted for rotation about a generally vertical axis, said annular member including a peripheral gear which cooperates with at least one further gear provided about the periphery of a second annular member from which also depends a cutter having a U-shaped blade, the arrangement being such that the rotational path of the first blade intersects that fo the second blade.

In another aspect, the invention provides a motor-driven rotavator comprising a handle and a first annular member having around its circumference a gear-wheel connected to impart r oration to a bladed cutter including a U-shaped blade which extends dow war ily from the undersurface of the annular member, and a second annular member also having around its circumference a gear-wheel connected to impart rotation to a bladed cutter including a U-shaped blade which extends downwardly from its undersurface, the gear-

wheel of the first annular member being positioned to impart drive to the gear-wheel of the second annular member, and the bladed cutters being so positioned that their rotational paths intersect.

The invention will now be described by way of example only with reference to the accompanying drawings, in which: Figure 1 is a side view partly in section through a rotavator according to the invention; Figure 2 is a front view of the rotavator shown in Figure 1; Figure 3 is a plan view from above of the cutting assembly of the illustrated rotavator; and Figure 4 is a plan view from below of the illustrated rotavator.

As can be seen from the Figures, the illustrated rotavator includes a rodlike handle 2, a housing 3 for an electric or petrol driven motor and a cutter assembly 4. A casing 6 protects and supports bladed cutters 8 of the cutter assembly.

A cylindrical gear-wheel lO driven by the drive shaft of the motor rotoidally engages the interior of a cavity in a sleeve 12 whose lower end extends into and engages a cylindrical gear-wheel 14 which, in turn, engages a gear 16 provided on the circumferential surface of a first annular member 18.

The annular member 18 is supported by a plurality of equiangular Wolves 20 which

extend from a central sleeve 22 supported by roller bearings 24.

The gear 16 of the annular member 18 engages two gears 26 provided on the circumferential surfaces of two further annular members 28 supported by spokes 30 which, as for annular member 18, extend from central sleeves supported by roller bearings.

To the lower end of each sleeve 22 there is secured a bladed cutter each of which comprises two substantially inverted U-shaped blades 32. As will be seen from Figure 3, the blades 32 of the cutters supported from the annular members 28 are mutually aligned and lie in planes which are generally perpendicular to the plane which includes the central annular member. This enables the areas tilled by the outer cutter blades to overlap to a limited extent with areas tilled by the inner cutter blade.

Additionally, each cutter blade is provided with two fins 34 which lie in a plane which is generally perpendicular to the plane passing through the corresponding blade.

The operation of the illustrated rotavator is traditional and comprises starting the motor to impart rotation to the gear-wheel 10 which consequently, by means of the coupling formed by the sleeve 12, the gear 14, the gear 16 and the gears 26, imparts rotation to the three cutter blades simultaneously.

From the aforegoing it is apparent that rotavators in accordance with the invention present numerous advantages over existing rotavators. and in particular. These include increased earth removal reliability because the paths travelled by the cutter blades mutually intersect; increased comfort for the user because the blades operate generally parallel to the ground; and easier penetration under foliage because of the relatively low height.

It will be appreciated that the foregoing is merely exemplary of rotavators in accordance with the invention and that various modifications can be made thereto without departing from the scope of the invention as set out in the accompanying claims.

Claims

1. A rotavator comprising a handle and a motor co.nneeted to impart rotation to an annular member whose axis is generally vertical and from which depends a cutter having a U-shaped blade mounted for rotation about a generally vertical axis, said annular member including a peripheral gear which cooperates with at least one further gear provided about the periphery of a second annular member from which also depends a cutter having a U-shaped blade, the arrangement being such that the rotational path of the first blade intersects that of the second blade.

2. A rotavator as claimed in claim 1 in which the drive shaft of the motor is positioned to impart drive to a gear-wheel which engages rotoidally with a toothed sleeve which engages the gear provided on the first annular member.

3. A rotavator as claimed in claim 1 or claim 2 wherein three annular members are provided, the first mentioned annular member imparting rotation to the other two annular members.

4. A rotavator as claimed in claim 1, wherein each bladed cutter is provided with fins disposed perpendicular to the plane of the U-shaped blades.

5. A motor-driven rotavator comprising a handle and a first annular member having around its circumference a gear-wheel connected to impart rotation to a bladed cutter including a U-shaped blade which extends downwardly from the undersurface of the annular member, and a second annular member also having around its circumference a gear-wheel connected to impart rotation to a bladed cutter including a U-shaped blade which extends downwardly from its undersurface, the gear-wheel of the first annular member being positioned to impart drive to the gear- wheel of the second annular member, and the bladed cutters being so positioned that their rotational paths intersect.

6. A rotavator substantially as herein described and as described with reference to the accompanying diagrammatic drawings.