GB2079575A

GB2079575A - Lawn-mower

Info

Publication number: GB2079575A
Application number: GB8120832A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-07-14
Filing date: 1981-07-06
Publication date: 1982-01-27
Also published as: FR2486355A1; DE3124230A1; GB2079575B

Abstract

A lawn-mower has a motor-driven, rotating cutter disc in a protective housing 10 and an additional rotor 17 having a cutting line 18 whose effective range lies outside that of the cutter disc 11, 12 but overlaps the cutting area of the cutter disc during travel. The rotor with the cutting line can either be fixed or adjustable and releasably connected to the housing 10 of the lawn-mower. The releasable device permits mowing adjacent to the lawn-mower, provided that the rotor 17 with its cutting line 18 is either driven by a flexible shaft 20 Fig. 2 (not shown) or has its own drive motor. <IMAGE>

Description

SPECIFICATION Lawn-mower The invention relates to lawn-mowers, particularly a motor-driven lawn-mower having a rotating cutter disc.

It is common knowledge that lawn-mowers of this kind have the disadvantage that they cannot mow, or can only mow with difficulty, obstructed or confined areas such as the edges of lawns along beds, walls, fences, hedges or around trees. The reason for this is that the cutter disc is surrounded by a protective hood to which the wheels are also secured. As a result, if the mower is used on a bed in an attempt to mow to the edge of a lawn adjoining the bed the wheels sink into soft earth in the bed. In the case of obstructions such as a wall or a fence, the protective hood prevents the cutter from getting sufficiently close to the obstruction.As a resu It if it is desired to cut the edges of lawns neatly around beds or other obstructions, in general a second, separate working operation is required with the remaining grass being, for example, cut manually with shears or in some other way.

It is accordingly an object of the invention to provide a lawn mower which is capable of avoiding the previously described disadvantage, and with which the edges of a lawn can be neatly mown in one working operation even in the case of a lawn having obstructions such as trees, fences, or along a wall.

Accordingly, the present invention provides a lawn-mower having a motor-driven, rotating cutter disc, characterised in that it is provided with at least one additional rotor having at least one cutting line whose effective range lies outside of that of the cutter disc and extends beyond the periphery of the protective housing of the cutter disc.

The cutter disc and the or each rotor having a cutting line each define separate effective cutting ranges in the form of circular areas. During normal forwards travel of the mower, the cutter disc and cutting line(s) pass over, and hence cut, separate areas in the form of strips or bands, the width of which equals the diameter of the relevant cutting circle.

The cutter disc and rotor or rotors must, of course, be arranged with respect to one another so that the respective circular cutting ranges do not contact or overlap with one another, and so do not hinder operation. However, by arranging for the axes of rotation of the cutter disc and the rotor or rotors to be appropriately laterally staggered with respect to one another in the direction of normal travel of the mower, so it can be arranged for the respective strips or bands cut thereby during use of the mower to overlap one another.

Common drive means, e.g. an electric motor (battery or mains driven) or a petrol engine, may be provided for both the cutter disc and rotor(s). In this case, the rotor is conveniently driven via a flexible shaft to enable adjustment of the position and/or orientation of the rotor(s) with respect to the mower housing and possibly also removal of the rotor from the housing for independent operation at a distance from the mower.

Alternatively, separate drive means may be provided for the cutter disc and for the rotor(s). The drive motor for the rotor(s) may, for instance, be an electric motor which is fed by a current generator driven by a drive motorforthe cutter disc. Alternatively, separate mains or battery powered electric motors may be provided for the cutter disc and for the rotor(s).

The invention will be further described, by way of example, with reference to the accompanying drawings.

Fig. lisa plan view from below of one embodiment of a lawn-mower in accordance with the invention having an additional rotor with cutting line fixedly disposed on the mower housing; and Fig. 2 is a side elevation view of a further embodiment of a lawn-mower in accordance with the invention, having an additional rotor the position of which relative to the housing is adjustable.

Referring to the drawings, the motor-driven lawn-mower illustrated in Fig. 1 comprises a housing 10 having a motor (not shown) mounted on top thereof. A cutter disc 11 having two blades 12 is disposed on the motor shaft and is located centrally in the housing 10. Four wheels 13 are mounted laterally on the housing 10 and are fixed or, according to the type of construction, are vertically adjustable. A pushing and steering handle 14 is articulated to the rear of the housing 10. An ejection opening 19, out of which the cut grass is ejected, is located on the left hand side of the housing as seen in Fig. 1. An additional rotor 17 having a cutting line 18 is provided with a shaft 16 which is rotatablyjournalled in a circular extension 15 on the front right hand side of the housing 10, the extension is being open towards the housing and towards the outside.

The shaft 16 is driven from above. By way of example, the top end of the motor shaft and the top end of the rotor shaft 16 can be provided with a V-belt pulley and the drive can be effected by means of a V-belt. This renders it possible to operate the rotor 17 at a higher rotational speed than that ofthe motor.

In Fig. 1 the effective cutting regions of the cutter disc 11 and ofthe cutting line 18 are indicated by dash-dot circles M and F, respectively. The paths mown by the cutter disc 11 and the cutting line 18 during forwards travelling operation of the lawnmower are designated Bm and Bf respectively. It will be seen that although the circles M and F do not overlap the paths Bm and Bf do overlap with one another.

The lawn-mower shown in side elevation in Fig. 2 resembles in certain respects the embodiment of Fig. 1, and like parts are designated by like reference numerals. However, the Fig. 2 embodiment differs from the lawn-mower described with reference to Fig. 1 in that, in the lawn-mower shown in Fig. 2, the rotor 17 with its cutting line 18 is driven by the cutter disc motor 21 by means of a flexible shaft 20.

This arrangement renders it possible to adjust the overhang of the rotor 17 as well as its height and slope relative to the housing 10, thereby enabling adaptation to various cutting conditions. By way of example, when cutting raised edges of lawns to size or at the transition of the lawn to paved paths or roads, etc., it is advantageous to adjust the plane of rotation of the cutting line 18 to perpendicular operation. Advantageously, horizontal operation is chosen when cutting along walls or around trees. Any intermediate stage can also provide the optimum result for special conditions.

The flexible shaft 20 is driven by means of two V-belt pulleys and a V-belt which are disposed in a housing 22. The housing 22 is mounted on top ofthe cover of the motor 21. One V-belt pulley is directly connected to the motor shaft, and the other V-belt pulley is rotatably mounted at 23 in the housing 22 and its journal is connected to the top end ofthe flexible shaft 20. The bottom end of the flexible shaft is connected to the shaft 16 which is journalled in a bearing housing 24. The bearing housing 24 is connected to the protective housing 10 of the lawn mower by means of an adjustable arm 25. The arm 25 permits lateral adjustment as well as oblique adjustment of the rotor 17 with its cutting line 18. If the arm 25 is released from the housing 10, the device with the cutting line can be used independently as a result ofthe flexible shaft. The distance at which the device can be operated from the lawn mower depends, of course, upon the length of the flexible shaft 20.

Further arrangements are possible in addition to the embodiments described above particularly in cases where the rotor with the cutting line has an individual drive motor. If the rotor with the cutting line has its own electric drive motor, the distance from the lawn mower at which the device with the cutting line can still be operated can be greater and only depends upon the length of the electric power supply cable. An arrangement ofthis kind is suitable for a lawn mower which is operated by a storage battery or which is fed from the mains, as well as for a lawn mowerwhich is driven buy a petrol engine and which has a current generator driven by the engine.

Claims

1. A lawn-mower having a motor-driven, rotating cutter.disc, characterised in that it is provided with at least one additional rotor having at least one cutting line whose effective range lies outside of that ofthe cutter disc and extends beyond the periphery of the protective housing of the cutter disc.

2. A lawn-mower according to claim 1, comprising a motor which is adapted to drive both the cutter disc and the rotor(s).

3. A lawn-mower according to claim 1, wherein the or each rotor is provided with an individual drive motor.

4. A lawn-mower according to claim 3, wherein the drive motor for the or each rotor is an electric motor which is adapted to be fed by a current generator driven by a drive motor for the cutter disc.

5. A lawn-mower according to claim 3, which has a storage battery or is fed from the mains supply, wherein the drive motor for the cutter disc is an electric motor and the drive motor for the or each rotor is an electric motor.

6. A lawn-mower according to claim 2, wherein the rotor having the cutting line is driven by means of a flexible shaft.

7. A lawn-mower according to any one of the preceding claims, wherein the or each rotor is releasable from the lawn-mower housing and is independently operable.

8. A lawn-mower according to any one of the preceding claims, wherein the or each rotor is vertically adjustable relative to the lawn-mower housing.

9. A lawn-mower according to any one of the preceding claims, wherein the slope of the or each rotor is adjustable relative to the lawn-mower housing.

10. A lawn-mower according to any one ofthe preceding claims, comprising more than one rotor having a cutting line.

11. A lawn-mower having a motor-driven, rotating cutter disc, substantially as herein described with reference to, and as shown in, Fig. 1 of the accompanying drawings.

12. A lawn-mower having a motor-driven, rotating cutter disc, substantially as herein described with reference to, and as shown in, Fig. 2. of the accompanying drawings.